tag:theconversation.com,2011:/us/topics/nanomaterials-13155/articlesNanomaterials – The Conversation2023-05-04T14:25:46Ztag:theconversation.com,2011:article/2049752023-05-04T14:25:46Z2023-05-04T14:25:46ZCloud seeding can increase rain and snow, and new techniques may make it a lot more effective – podcast<figure><img src="https://images.theconversation.com/files/524204/original/file-20230503-19-bx8o26.jpg?ixlib=rb-1.1.0&rect=418%2C594%2C6930%2C4308&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cloud seeding can increase rainfall and reduce hail damage to crops, but its use is limited.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/colorado-supercell-royalty-free-image/1303884216?phrase=Rain+storm&adppopup=true">John Finney Photography/Moment via Getty Images</a></span></figcaption></figure><p>When an unexpected rainstorm leaves you soaking wet, it is an annoyance. When a drought leads to fires, crop failures and water shortages, the significance of weather becomes vitally important.</p>
<p>If you could control the weather, would you?</p>
<p>Small amounts of rain can mean the difference between struggle and success. For <a href="https://climateviewer.com/2014/03/25/history-cloud-seeding-pluviculture-hurricane-hacking/">nearly 80 years</a>, an approach called cloud seeding has, in theory, given people the ability to get more rain and snow from storms and make hailstorms less severe. But only recently have scientists been able to peer into clouds and begin to understand how effective cloud seeding really is.</p>
<p>In this episode of “The Conversation Weekly,” we speak with three researchers about the simple yet murky science of cloud seeding, the economic effects it can have on agriculture, and research that may allow governments to use cloud seeding in more places.</p>
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<p><a href="https://scholar.google.com/citations?user=BSQl42wAAAAJ&hl=en&oi=ao">Katja Friedrich</a>, a professor of atmospheric and oceanic sciences at the University of Colorado, Boulder in the U.S., is a leading researcher on cloud seeding. “When we do cloud seeding, we are looking for clouds that have tiny super-cooled liquid droplets,” she explains. Silver iodide is very similar in structure to an ice crystal. When the droplets touch a particle of silver iodide, “they freeze, then they can start merging with other ice crystals, become snowflakes and fall out of the cloud.”</p>
<p>While the process is fairly straightforward, measuring how effective it is in the real world is not, according to Friedrich. “The problem is that once we modify a cloud, it’s really difficult to say what would’ve happened if you hadn’t cloud-seeded.” It’s hard enough to predict weather without messing with it artificially. </p>
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<a href="https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A plane wing with a cylindrical device attached." src="https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=370&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=370&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=370&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=465&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=465&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524222/original/file-20230503-1294-7b7p2j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=465&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Cloud seeding is usually done by planes equipped with devices – like the one attached to the wing of this plane – that spray silver iodide into the atmosphere.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Cloud_seeding#/media/File:Hagelflieger-EDTD.jpg">Zuckerle/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>In 2017, Friedrich’s research group had a breakthrough in measuring the effect of cloud seeding. “We flew some aircraft, released silver iodide and generated these clouds that were like these six exact lines that were downstream of where the aircraft were seeding,” she says. They then had a second aircraft fly through the clouds. “We could actually <a href="https://doi.org/10.1073/pnas.1716995115">quantify how much snow we could produce</a> by two hours of cloud seeding.” That effect, according to research on cloud seeding, is an increase in precipitation of somewhere around 5% to 20% or 30%, depending on conditions.</p>
<p>Measuring the effect on precipitation – whether rain or snow – directly may have taken complex science and a bit of luck, but in places that have been using cloud seeding for long periods of time, the economic benefits are shockingly clear. </p>
<p><a href="https://www.ndsu.edu/agriculture/ag-home/directory/dean-bangsund">Dean Bangsund</a> is a researcher at North Dakota State University who studies the economics of agriculture. “We have a high amount of hail damage in North Dakota,” said Bangsund. For decades, the state government has been using cloud seeding to reduce hail damage, as cloud seeding leads to the formation of more pieces of smaller hail compared to fewer pieces of larger hail. “It doesn’t 100% eliminate hail; it’s designed to soften the impact.”</p>
<p>Every 10 years, the state of North Dakota does an <a href="https://www.cabdirect.org/cabdirect/abstract/20193399635">analysis on the economic impacts of the cloud seeding</a> program, measuring both reduction in hail damage and benefits from increased rain. Bangsund led the last report and says that for every dollar spent on the cloud seeding program, “we are looking at something that is anywhere from $8 or $9 in benefit on the really lowest scale, up to probably $20 of impact per acre.” With millions of acres of agricultural fields in the cloud seeding area, that is a massive economic benefit.</p>
<p>Both Freidrich and Bangsund emphasized that cloud seeding, while effective in some cases, cannot be used everywhere. There is also a lot of uncertainty in how much of an effect it has. One way to improve the effectiveness and applicability of cloud seeding is by improving the seed. <a href="https://scholar.google.com/citations?view_op=list_works&hl=en&hl=en&user=OxrNpiEAAAAJ&sortby=pubdate">Linda Zou</a> is a professor of civil infrastructure and environmental engineering at Khalifa University in the United Arab Emirates. </p>
<p>Her work has focused on developing a replacement for silver iodide, and her lab has <a href="https://www.technologyreview.com/2022/03/28/1048275/scientists-advance-cloud-seeding-capabilities-with-nanotechnology/">developed what she calls a nanopowder</a>. “I start with table salt, which is sodium chloride,” says Zou. “This desirable-sized crystal is then coated with a thin nanomaterial layer of titanium dioxide.” When salt gets wet, it melts and forms a droplet that can efficiently merge with other droplets and fall from a cloud. Titanium dioxide attracts water. Put the two together and you get a very effective cloud-seeding material. </p>
<p>From indoor experiments, Zou found that “with the nanopowders, there are 2.9 times the formation of larger-size water droplets.” These nanopowders can also form ice crystals at warmer temperatures and less humidity than silver iodide. </p>
<p>As Zou says, “if the material you are releasing is more reactive and can work in a much wider range of conditions, that means no matter when you decide to use it, the chance of success will be greater.”</p>
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<p>This episode was written and produced by Katie Flood. Mend Mariwany is the executive producer of The Conversation Weekly. Eloise Stevens does our sound design, and our theme music is by Neeta Sarl.</p>
<p>You can find us on Twitter <a href="https://twitter.com/TC_Audio">@TC_Audio</a>, on Instagram at <a href="https://www.instagram.com/theconversationdotcom/">theconversationdotcom</a> or <a href="mailto:podcast@theconversation.com">via email</a>. You can also subscribe to The Conversation’s <a href="https://theconversation.com/newsletter">free daily email here</a>. </p>
<p>Listen to “The Conversation Weekly” via any of the apps listed above, download it directly via our <a href="https://feeds.acast.com/public/shows/60087127b9687759d637bade">RSS feed</a> or find out <a href="https://theconversation.com/how-to-listen-to-the-conversations-podcasts-154131">how else to listen here</a>.</p>
<hr><img src="https://counter.theconversation.com/content/204975/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>None of the interviewees work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p><p class="fine-print"><em><span> </span></em></p>Cloud seeding – spraying materials into clouds to increase precipitation – has been around for nearly 80 years. But only recently have scientists been able to measure how effective it really is.Daniel Merino, Associate Science Editor & Co-Host of The Conversation Weekly Podcast, The ConversationNehal El-Hadi, Science + Technology Editor & Co-Host of The Conversation Weekly Podcast, The ConversationLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1979972023-03-13T13:36:22Z2023-03-13T13:36:22ZFrom waste to clean water: tiny carbon particles can do the job<figure><img src="https://images.theconversation.com/files/512388/original/file-20230227-20-kep09i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Clean water is in short supply around the world. But it doesn't have to be.</span> <span class="attribution"><span class="source">borgogniels/Getty Images</span></span></figcaption></figure><p>Many futuristic novels and films have explored what the world might look like without water. But water scarcity isn’t a problem for the far-off future: it’s already here.</p>
<p>In its <a href="https://www.unwater.org/publications/summary-progress-update-2021-sdg-6-water-and-sanitation-all">2021 report</a> UN Water outlined the scale of the crisis: 2.3 billion people live in water-stressed countries and 733 million of those people are in “high and critically water-stressed countries”.</p>
<p>In 2018 Cape Town, where I live and conduct my research, residents found themselves staring down “<a href="https://www.theguardian.com/world/2018/may/04/back-from-the-brink-how-cape-town-cracked-its-water-crisis">day zero</a>”, when household water supplies would run dry. Good rains spared the South African city, but now other parts of the country face <a href="https://www.dailymaverick.co.za/article/2022-10-04-day-zero-comes-to-parts-of-joburg-as-water-cuts-roll-through-city-and-taps-run-dry/">similarly dire</a> predictions of empty taps. </p>
<p>This scenario is threatening to play out across Africa. In the <a href="https://climatechampions.unfccc.int/is-eastern-africas-drought-the-worst-in-recent-history-and-are-worse-yet-to-come/">Horn of Africa</a> region, for example, large areas of Ethiopia, Somalia and Kenya have seen four consecutive rainy seasons pass without decent rains. The rise of “<a href="https://www.afdb.org/en/news-and-events/particularly-exposed-climate-shocks-african-cities-are-turning-adaptation-and-resilience-56462">megacities</a>” in Africa – with millions moving into city areas – puts further pressures on already limited infrastructure.</p>
<p>And the crisis extends <a href="https://www.unwater.org/publications/summary-progress-update-2021-sdg-6-water-and-sanitation-all">far beyond the African continent</a>. </p>
<p>There is no one solution for this grim reality. A multi-pronged approach will be necessary, as Cape Town’s experience <a href="https://www.businessinsider.co.za/water-tips-2022-10">illustrated</a>.</p>
<p>Technology will be a key part of solving the global water scarcity crisis. Technological solutions can run the gamut from the most basic, like water leak detectors for households, to highly sophisticated, like ways to <a href="https://borgenproject.org/top-4-technologies-solving-water-scarcity/">pull moisture out of the air</a> to produce clean drinking water, or convert the planet’s abundant salt water into fresh water.</p>
<p>In a <a href="https://onlinelibrary.wiley.com/doi/epdf/10.1002/cben.202100003">recent paper</a> colleagues and I outlined another potentially powerful technology: carbon nanomaterials, which have <a href="https://www.sciencedirect.com/science/article/pii/S221478532100420X">been shown</a> to remove organic, inorganic and biological pollutants from water. </p>
<h2>Contamination threatens water sources</h2>
<p>Contamination is one of the factors putting strain on water sources. All water supplies contain some microbes and pathogens. But industrial waste is a huge problem: vehicles release heavy metal pollutants, for instance, and <a href="https://www.wits.ac.za/news/latest-news/research-news/2018/2018-05/the-heat-of-acid-mine-drainage.html#:%7E:text=The%20water%20becomes%20acidic%20and,the%20drinking%20water%20supply%20system">acid mine drainage</a> seeps into water sources. This results in contaminated ground and surface water that cannot be safely used for most human activities, much less for drinking or washing food.</p>
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Read more:
<a href="https://theconversation.com/marine-life-in-a-south-african-bay-is-full-of-chemical-pollutants-182791">Marine life in a South African bay is full of chemical pollutants</a>
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<p>Some current technologies make the treatment of water too expensive. Others are simply not up to the job and are unable to remove microorganisms. In removing organic pollutants like pharmaceutical waste, organic dyes, plastics and detergents from wastewater, for instance, some conventional techniques such as membrane filtration have been found wanting. </p>
<p>That’s where carbon nanomaterials come in. With others, I am exploring their use and finding that they are more efficient and economically viable than conventional materials.</p>
<h2>Nanomaterials</h2>
<p>Nanomaterials are broadly defined as materials that contain particles of between 1 and 100 nanometres (nm) in size. One nanometre equals one-billionth of a metre. Different nanomaterials are composed of different atoms – some, like those I research, are made up of carbon atoms.</p>
<p>Carbon is, by mass, the second most abundant <a href="https://www.thoughtco.com/most-abundant-element-in-the-universe-602186">element</a> in the human body after oxygen. It is also a common element of all known life. Carbon nanotechnologies are environmentally friendly because they hold less risk of secondary pollution than some adsorbents (solid substances used to remove contaminants from liquid or gas).</p>
<p>Engineered into nanomaterial form, carbon nanomaterials are being <a href="https://www.scientificamerican.com/article/nanomaterials-could-combat-climate-change-and-reduce-pollution/">hailed</a> by many scientists around the world for their superior physical and chemical properties. They are increasingly prized for their potential to remove heavy metals from water thanks to their large <a href="https://www.diffen.com/difference/Absorption_vs_Adsorption">surface area and adsorption</a> capabilities, their nano-scaled size and their chemical properties. </p>
<p>Carbon nanomaterials have all been <a href="https://iopscience.iop.org/article/10.1088/2053-1591/ac48b8#:%7E:text=Carbon%20nanomaterials%20are%20applied%20in,with%20the%20rise%20of%20nanotechnology.">shown</a> to be effective in the treatment of wastewater.</p>
<h2>Tackling water scarcity</h2>
<p>I work with carbon-coated magnetic nanomaterials. This blended composite plays a crucial role in decontaminating water. At the same time, it removes materials such as heavy metals. That makes it ideal for water treatment, as do its easy, fast recovery and recyclability, thanks to what’s known as magnetic filtration. In this process, the magnetic nanomaterials added to the contaminated water are recovered after treatment by an external strong magnet. The recovered materials can be regenerated and be reused again.</p>
<p>Carbon-based nanomaterials still have shortcomings. Nanomaterials tend to clump together into large particles, reducing their capacity to adsorb (attract and hold) pollutants. And nanoparticles are not always fully recovered from treated water, leading to secondary contamination. We’re still not sure how to separate exhausted – fully utilised – nanomaterials from treated water.</p>
<p>The work continues in our lab and others all over the world. Scientists dislike timelines, since breakthroughs rarely happen within set deadlines. But our hope is that more and more advances will be made with carbon-based nanonmaterials in the years to come, giving the world an important tool to tackle water scarcity.</p><img src="https://counter.theconversation.com/content/197997/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Salam Titinchi does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Technology will be a key part of solving the global water scarcity crisis.Salam Titinchi, Professor, University of the Western CapeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1942382022-11-29T13:34:50Z2022-11-29T13:34:50ZGraphene is a proven supermaterial, but manufacturing the versatile form of carbon at usable scales remains a challenge<figure><img src="https://images.theconversation.com/files/497098/original/file-20221123-22-6q2g12.jpg?ixlib=rb-1.1.0&rect=17%2C34%2C1260%2C770&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Graphene has many incredible physical properties that arise from its one-atom-thick carbon structure.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Graphen.jpg#/media/File:Graphen.jpg">AlexanderAlUS/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>“Future chips may be <a href="https://www.msn.com/en-us/news/technology/future-chips-may-be-10-times-faster-all-thanks-to-graphene/ar-AA14qqsu">10 times faster, all thanks to graphene</a>”; “Graphene may be <a href="https://www.newswise.com/coronavirus/wonder-material-can-be-used-to-detect-covid-19-quickly-accurately/?article_id=753042">used in COVID-19 detection</a>”; and “Graphene allows batteries to <a href="https://www.theverge.com/22771702/graphene-power-bank-review-price-speed">charge 5x faster</a>” – those are just a handful of recent dramatic headlines lauding the possibilities of graphene. Graphene is an incredibly light, strong and durable material made of a single layer of carbon atoms. With these properties, it is no wonder researchers have been studying ways that graphene could advance material science and technology for decades.</p>
<p>I never know what to expect when I tell people <a href="https://scholar.google.com/citations?user=yykU46oAAAAJ&hl=en&oi=ao">I study graphene</a> – some have never heard of it, while others have seen some version of these headlines and inevitably ask, “So what’s the holdup?” </p>
<p>Graphene is a fascinating material, just as the sensational headlines suggest, but it is only just starting be used in real-world applications. The problem lies not in graphene’s properties, but in the fact that it is still incredibly difficult and expensive to manufacture at commercial scales.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A black and white image of a crystalline layer on a surface." src="https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=554&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=554&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=554&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=697&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=697&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497095/original/file-20221123-20-ztyacw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=697&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pure graphene is a uniform, single-atom-thick crystal of carbon arranged in a hexagonal pattern, as seen in this electron microscope image.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Graphene-TEM.jpg#/media/File:Graphene-TEM.jpg">M.H. Gass/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>What is graphene?</h2>
<p>Graphene is most simply defined as a single layer of carbon atoms bonded together in a hexagonal, sheetlike structure. You can think of pure graphene as a one-layer-thick sheet of carbon tissue paper that happens to be the strongest material on Earth. </p>
<p>Graphene usually comes in the form of a powder made of small, individual sheets that are roughly the diameter of a grain of sand. An individual sheet of graphene is <a href="https://doi.org/10.1126/science.1235126">200 times stronger than an equally thin piece of steel</a>. Graphene is also <a href="https://doi.org/10.1038/nature26160">extremely conductive</a>, holds together at <a href="https://doi.org/10.3367/UFNe.0184.201410c.1045">up to 1,300 degrees Fahrenheit (700 C)</a>, can <a href="https://doi.org/10.1016/j.cej.2019.05.034">withstand acids</a> and is <a href="https://news.mit.edu/2017/3-d-graphene-strongest-lightest-materials-0106">flexible and very lightweight</a>.</p>
<p>Because of these properties, graphene could be extremely useful. The material can be used to <a href="https://www.azonano.com/article.aspx?ArticleID=5468#">create flexible electronics</a> and to <a href="https://www.azocleantech.com/article.aspx?ArticleID=936">purify or desalinate water</a>. And adding just 0.03 ounces (1 gram) of graphene to 11.5 pounds (5 kilograms) of cement <a href="https://firstgraphene.net/applications/concrete/#:%7E:text=The%20use%20of%20graphene%20concrete,new%20generation%20of%20concrete%20designs">increases the strength of the cement by 35%</a>. </p>
<p>As of late 2022, Ford Motor Co., with which I worked as part of my doctoral research, is one of the the only companies to use graphene at industrial scales. Starting in 2018, Ford began making plastic for its vehicles that was 0.5% graphene – <a href="https://media.ford.com/content/fordmedia/fna/us/en/news/2018/10/09/ford-innovates-with-miracle-material-powerful-graphene-for-vehicle-parts.html">increasing the plastic’s strength by 20%</a>.</p>
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<a href="https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A close-up photo of the tip of a pencil writing on paper." src="https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497097/original/file-20221123-26-1wxtw5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers made the first piece of graphene by peeling layers of carbon off of graphite – or pencil lead – with tape.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/macro-pencil-tip-resting-on-blank-white-paper-royalty-free-image/856908132?phrase=pencil%20lead&adppopup=true">Rapid Eye/E+ via Getty Images</a></span>
</figcaption>
</figure>
<h2>How to make a supermaterial</h2>
<p>Graphene is produced in two principal ways that can be described as either a top-down or bottom-up process.</p>
<p>The world’s <a href="https://www.graphene-info.com/graphene-history-controversy-and-nobel-prize">first sheet of graphene</a> was created in 2004 out of graphite. Graphite, commonly known as pencil lead, is composed of millions of graphene sheets stacked on top of one another. Top-down synthesis, also known as <a href="https://www.azonano.com/article.aspx?ArticleID=5471">graphene exfoliation</a>, works by peeling off the thinnest possible layers of carbon from graphite. Some of the earliest graphene sheets were made by using cellophane tape to <a href="https://science.wonderhowto.com/how-to/make-graphene-sheets-from-graphite-flakes-and-cellophane-tape-402113/">peel off layers of carbon from a larger piece of graphite</a>. </p>
<p>The problem is that the molecular forces holding graphene sheets together in graphite are very strong, and it’s hard to pull sheets apart. Because of this, graphene produced using top-down methods is often many layers thick, has holes or deformations, and <a href="https://doi.org/10.1002/adma.201803784">can contain impurities</a>. Factories can produce a few tons of mechanically or chemically exfoliated graphene per year, and for many applications – like mixing it into plastic – the <a href="https://www.compositesworld.com/articles/graphene-101-forms-properties-and-applications">lower-quality graphene works well</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A thin, folded, rough-edged piece of graphene." src="https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497094/original/file-20221123-16-meka9j.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Graphene flakes made from top-down methods are usually more than one atom thick and have impurities like folds and tears, as seen in this image.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Graphene_flakes.JPG#/media/File:Graphene_flakes.JPG">Дагесян Саркис Арменакович/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Top-down, exfoliated graphene is far from perfect, and some applications do need that pristine single sheet of carbon. </p>
<p>Bottom-up synthesis builds the carbon sheets one atom at a time over a few hours. This process – called <a href="https://www.graphenea.com/pages/cvd-graphene#.Y3vcF3bMI2w">vapor deposition</a> – allows researchers to produce high-quality graphene that is one atom thick and up to 30 inches across. This yields graphene with the best possible mechanical and electrical properties. The problem is that with a bottom-up synthesis, it can take <a href="https://doi.org/10.1021/acs.chemrev.8b00325">hours to make even 0.00001 gram</a> – not nearly fast enough for any large scale uses like in <a href="https://doi.org/10.1038/nnano.2010.132">flexible touch-screen electronics or solar panels</a>, for example.</p>
<h2>So what’s the holdup?</h2>
<p>Current production methods of graphene, both top-down and bottom-up, are expensive as well as energy and resource intensive, and simply produce too little product, too slowly. </p>
<p>Some companies do manufacture graphene and sell it for <a href="https://bigthink.com/the-present/flash-graphene/">US$60,000 to $200,000 per ton</a>. There are a limited number of uses that make sense at these high costs.</p>
<p>While small amounts of top-down or bottom-up graphene can satisfy the needs of researchers, for companies even just the process of prototyping a new material, application or manufacturing process requires many pounds of graphene powder or hundreds of graphene sheets and a lot of time and effort. It took significant investment and more than four years of study, development and optimization before graphene hit the production line at Ford. </p>
<p>Current production can barely cover experimentation, much less widespread use. </p>
<h2>Improving manufacturing</h2>
<p>For a material that has been around since only 2004, a lot of progress has been made in scaling up the production and implementation of graphene. </p>
<p>There are hints that graphene is starting to break through at a commercial level. There are a huge number of <a href="https://fortune.com/2020/12/13/what-is-graphene-entrepreneurs-headphones-smartphones-construction-eco-friendly-thinnest-material-on-earth/">graphene-related startups looking at a wide range of uses</a> ranging from <a href="https://nanotechenergy.com/">energy storage</a> to <a href="https://graphmatech.com/">composites</a> to <a href="https://www.inbrain-neuroelectronics.com/">nerve stimulation</a>. Major companies – such as <a href="https://electrek.co/2022/03/22/elon-musk-tesla-working-new-manganese-battery-cell/">Tesla</a>, <a href="https://www.thegraphenecouncil.org/blogpost/1501180/347505/LG-Electronics-Secures-Its-Position-in-CVD-Graphene-Production">LG</a> and <a href="https://www.thegraphenecouncil.org/blogpost/1501180/359799/BASF-Applies-Expertise-to-Graphene-Commercialization">chemical giant BASF</a> – are also investigating how graphene could be used, in rechargeable batteries, flexible or wearable electronics and next-generation materials.</p>
<p>Graphene is ripe for a breakthrough that will bring down the cost and increase the scale of production, and this is an <a href="https://www.phdassistance.com/blog/graphenes-for-research-and-the-growing-number-of-publications-per-year/">area of intense academic research</a>. One new technique discovered in 2020, called <a href="https://doi.org/10.1038/s41586-020-1938-0">flash joule heating</a>, is especially promising. Researchers have shown that passing large amounts of electricity through any carbon source reorganizes the carbon-carbon bonds into a graphene structure. Using this process, it is possible to make many pounds of high-quality graphene for a relatively low cost out of any carbon-containing material like coal or even trash. A <a href="https://www.universalmatter.com/">company called Universal Matter Inc.</a> is already commercializing the process.</p>
<p>Once the cost of graphene comes down, the commercial applications will follow. The <a href="https://www.fortunebusinessinsights.com/graphene-market-102930">appetite for graphene is huge</a>, but it is going to take some time before this material lives up to its potential.</p><img src="https://counter.theconversation.com/content/194238/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kevin Wyss receives funding through the NSF Graduate Research Fellowship, as well as the Rice University Stauffer-Rothrock Fellowship. He has worked in collaboration with Ford Motor Company and Universal Matter, but is not an employee.</span></em></p>Graphene is superstrong and superconductive, and it has applications in everything from construction to electronics. But to date there have been almost no commercial uses of the material.Kevin Wyss, PhD Student in Chemistry, Rice UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1826862022-06-08T13:57:17Z2022-06-08T13:57:17ZHow nanotechnology can revive Nigeria’s textile industry<figure><img src="https://images.theconversation.com/files/463265/original/file-20220516-12-9rfjk1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Yannick Folly/AFP via Getty Images </span> </figcaption></figure><p>Nigeria’s cotton production has fallen steeply in recent years. It once supported the <a href="https://allianceforscience.cornell.edu/blog/2019/04/nigeria-moves-revive-textile-industry/">largest</a> textile industry in Africa. The fall is due to weak demand for cotton and to poor yields resulting from planting <a href="https://www.sunnewsonline.com/how-nigerias-losing-6-5bn-cotton-export-revenue/#:%7E:text=Lack%20of%20improved%20seeds%2C%20access,export%20opportunities%20in%20cotton%20annually.">low-quality cottonseeds</a>. For these reasons, farmers switched from cotton to other crops.</p>
<p>Nigeria’s cotton <a href="https://msmestoday.com/agribusiness/production/nigerias-cotton-production-to-account-for-20-29-of-africas-production-by-2029/">output</a> fell from 602,400 tonnes in 2010 to 51,000 tonnes in 2020. In the 1970s and early 1980s, the country’s <a href="https://allianceforscience.cornell.edu/blog/2019/04/nigeria-moves-revive-textile-industry/">textile industry</a> had 180 textile mills employing over 450,000 people, supported by about 600,000 cotton farmers. <a href="https://oxfordbusinessgroup.com/analysis/fabric-society-textiles-look-make-comeback-thanks-abundance-raw-materials">By 2019</a>, there were 25 textile mills and 25,000 workers. </p>
<p>The industry competes in a global textile market that was <a href="https://www.grandviewresearch.com/industry-analysis/textile-market">valued</a> at US$ 993.6 billion in 2021 and is expected to grow at a rate of 4.0% from 2022 to 2030. Once the continent’s leader, Nigeria <a href="https://www.vanguardngr.com/2019/12/nigeria-spends-4-billion-to-import-textiles-yearly/">spends</a> on average US$4 billion a year to import textiles that it could produce itself. Imports put pressure on foreign exchange reserves, jobs and local demand for cotton.</p>
<p>Technical innovation could make the textile sector more competitive – not only by <a href="https://jcottonres.biomedcentral.com/articles/10.1186/s42397-021-00092-6">improving cotton</a> production but also by improving textile quality. This can be achieved in Nigeria. </p>
<p>Nowadays, textiles’ properties can be greatly improved through nanotechnology – the use of extremely small materials with special properties. Nanomaterials like graphene and silver nanoparticles <a href="https://www.azonano.com/article.aspx?ArticleID=5501">make</a> textiles stronger, durable, and resistant to germs, radiation, water and fire.</p>
<p>Adding nanomaterials to textiles <a href="https://www.sciencedirect.com/science/article/abs/pii/S1387700322002350">produces</a> nanotextiles. These are often “smart” because they respond to the external environment in different ways when combined with electronics. They can be <a href="https://aip.scitation.org/doi/10.1063/1.5123575">used</a> to harvest and store energy, to release drugs, and as sensors in different applications. </p>
<p>Nanotextiles are increasingly used in defence and healthcare. For hospitals, they are used to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3688167/">produce</a> bandages, curtains, uniforms and bedsheets with the ability to kill pathogens. The <a href="https://www.statista.com/statistics/1038209/global-nanotextiles-market-value/">market value</a> of nanotextiles was US$5.1 billion in 2019 and could reach US$14.8 billion in 2024. </p>
<p>At the moment, Nigeria is not benefiting from nanotextiles’ economic potential as it produces none. With over <a href="https://www.unfpa.org/data/world-population/NG">216 million people</a>, the country should be able to support its textile industry. It could also explore <a href="https://www.cbn.gov.ng/MonetaryPolicy/afcfta.asp">trading opportunities</a> in the African Continental Free Trade Agreement to market innovative nanotextiles. </p>
<h2>Nanotextiles in Nigeria</h2>
<p>Our nanotechnology research group has made the first attempt to produce nanotextiles using cotton and silk in Nigeria. We used <a href="https://www.sciencedirect.com/science/article/pii/S2352186421007252">silver</a> and <a href="https://www.sciencedirect.com/science/article/abs/pii/S1387700322002350">silver-titanium oxide</a> nanoparticles produced by locust beans’ wastewater. <a href="https://www.feedipedia.org/node/268">Locust bean</a> is a multipurpose tree legume found in Nigeria and some other parts of Africa. The seeds, the fruit pulp and the leaves are used to prepare foods and drinks. </p>
<p>The seeds are used to <a href="https://iopscience.iop.org/article/10.1088/1755-1315/655/1/012012/meta">produce</a> a local condiment called “iru” in southwest Nigeria. The processing of iru generates a large quantity of wastewater that is not useful. We used the wastewater to reduce some compounds to produce silver and silver-titanium nanoparticles in the laboratory.</p>
<p>Fabrics were dipped into nanoparticle solutions to make nanotextiles. Thereafter, the nanotextiles were exposed to known bacteria and fungi. The growth of the organisms was monitored to determine the ability of the nanotextiles to kill them.</p>
<p>The nanotextiles prevented growth of several pathogenic bacteria and black mould, making them useful as antimicrobial materials. They were active against germs even after being washed five times with detergent. Textiles without nanoparticles did not prevent the growth of microorganisms.</p>
<p>These studies showed that nanotextiles can kill harmful microorganisms including those that are resistant to drugs. Materials such as air filters, sportswear, nose masks, and healthcare fabrics produced from nanotextiles possess excellent antimicrobial attributes. Nanotextiles can also promote wound healing and offer resistance to radiation, water and fire. </p>
<p>Our studies established the value that nanotechnology can add to textiles through hygiene and disease prevention. Using nanotextiles will promote good health and well-being for sustainable development. They will assist to reduce infections that are caused by germs.</p>
<p>Despite these benefits, nanomaterials in textiles can have some unwanted effects on the environment, health and safety. Some nanomaterials can harm human health causing irritation when they come in contact with skin or inhaled. Also, their release to the environment in large quantities can harm lower organisms and reduce growth of plants. We recommend that the impacts of nanotextiles should be evaluated case by case before use.</p>
<h2>Reviving Nigeria’s textile sector</h2>
<p>In addition to <a href="https://www.thisdaylive.com/index.php/2021/06/02/emefiele-revival-of-cotton-textile-industries-critical-for-economic-recovery/">government’s efforts</a> to revive Nigeria’s textile sector, opportunities in nanotechnology should be explored. Smart nanotextiles that can compete favourably with foreign textiles could be produced locally. </p>
<p>Agriculture can <a href="https://www.frontiersin.org/articles/10.3389/fnano.2020.579954/full">benefit</a> from nanopesticides, nanofungicides and nanofertilizers boosting crop yield. This has been <a href="https://jcottonres.biomedcentral.com/articles/10.1186/s42397-021-00092-6">applied</a> to cotton farming. Nanotechnology is also useful to <a href="https://www.sciencedirect.com/science/article/pii/S2214785320326341">treat effluents</a> of the textile industry in an eco-friendly manner. </p>
<p>Together with higher cotton production, nanotextile products can return Nigeria’s textile industry to glory. This is a unique way to improve Nigeria’s economy by nanotechnology.</p>
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Read more:
<a href="https://theconversation.com/nanotechnology-has-much-to-offer-nigeria-but-research-needs-support-180918">Nanotechnology has much to offer Nigeria but research needs support</a>
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<img src="https://counter.theconversation.com/content/182686/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Agbaje Lateef receives funding from TETFund. </span></em></p>Together with higher cotton production, nanotextile products can boost Nigeria’s textile industry and the economy.Agbaje Lateef, Professor of Microbiology, Ladoke Akintola University of Technology, Ogbomoso Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1800092022-05-04T18:02:21Z2022-05-04T18:02:21ZNanoparticles are the future of medicine – researchers are experimenting with new ways to design tiny particle treatments for cancer<figure><img src="https://images.theconversation.com/files/461078/original/file-20220503-38813-i2h2zm.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2121%2C1412&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nanoparticles can help cancer drugs home in on tumors and avoid damaging healthy cells.
</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/destruction-of-a-cancer-cell-illustration-royalty-free-illustration/713780459">Kateryna Kon/Science Photo Library via Getty Images</a></span></figcaption></figure><p>When you hear the word “nanomedicine,” it might call to mind scenarios like those in the 1966 movie “<a href="https://www.youtube.com/watch?v=dO5E4wkg0hA">Fantastic Voyage</a>.” The film portrays a medical team shrunken down to ride a microscopic robotic ship through a man’s body to clear a blood clot in his brain. </p>
<p>Nanomedicine has not reached that level of sophistication yet. Although scientists can generate nanomaterials smaller then several nanometers – the “nano” indicating one-billionth of a meter – today’s nanotechnology has not been able to generate functional electronic robotics tiny enough to inject safely into the bloodstream. But since the <a href="https://doi.org/10.1038/nnano.2006.115">concept of nanotechnology</a> was first introduced in the 1970s, it has made its mark in many everyday products, including electronics, fabrics, food, water and air treatment processes, cosmetics and drugs. Given these successes across different fields, many medical researchers were eager to use nanotechnology to diagnose and treat disease.</p>
<p>I am a <a href="https://scholar.google.com/citations?user=Ufab1aYAAAAJ&hl=en">pharmaceutical scientist</a> who was inspired by the promise of nanomedicine. <a href="https://pharmacy.umich.edu/sun-lab">My lab</a> has worked on developing cancer treatments using nanomaterials over the past 20 years. While nanomedicine has seen many successes, some researchers like me have been disappointed by its <a href="https://doi.org/10.1016/j.jconrel.2019.05.044">underwhelming overall performance</a> in cancer. To better translate success in the lab to treatments in the clinic, we proposed a <a href="https://doi.org/10.1021/acsnano.9b09713">new way to design</a> cancer drugs using nanomaterials. Using this strategy, we <a href="https://www.science.org/doi/10.1126/scitranslmed.abl3649">developed a treatment</a> that was able to achieve full remission in mice with metastatic breast cancer. </p>
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<figcaption><span class="caption">While nanomedicine isn’t “Fantastic Voyage,” it shares the film’s treatment goal of delivering a drug exactly where it needs to go.</span></figcaption>
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<h2>What is nanomedicine?</h2>
<p><a href="https://doi.org/10.1021/acsnano.9b09713">Nanomedicine</a> refers to the use of materials at the nanoscale to diagnose and treat disease. Some researchers define nanomedicine as encompassing any medical products using nanomaterials smaller than 1,000 nanometers. Others more narrowly use the term to refer to injectable drugs using nanoparticles smaller than 200 nanometers. Anything larger may not be safe to inject into the bloodstream.</p>
<p>Several nanomaterials have been successfully used in vaccines. The most well-known examples today are the <a href="https://doi.org/10.1016/j.ijpharm.2021.120586">Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines</a>. These vaccines used a nanoparticle made of of lipids, or fatty acids, that helps carry the mRNA to where it needs to go in the body to trigger an immune response.</p>
<p>Researchers have also successfully used nanomaterials in diagnostics and medical imaging. <a href="https://www.fda.gov/media/145080/download">Rapid COVID-19 tests</a> and <a href="https://doi.org/10.1016/s1028-4559(08)60127-8">pregnancy tests</a> use gold nanoparticles to form the colored band that designates a positive result. <a href="https://doi.org/10.1186/s13244-019-0771-1">Magnetic resonance imaging, or MRI</a>, often uses nanoparticles as contrast agents that help make an image more visible.</p>
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<figcaption><span class="caption">Gold is one type of nanoparticle whose uses researchers are testing in a range of contexts.</span></figcaption>
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<p>Several nanoparticle-based drugs have been approved for cancer treatment. <a href="https://doi.org/10.1016/j.jconrel.2012.03.020">Doxil (doxorubicin)</a> and <a href="https://dx.doi.org/10.4172%2F2157-7439.1000164">Abraxane (paclitaxel)</a> are chemotherapy drugs that use nanomaterials as a delivery mechanism to improve treatment efficacy and reduce side effects.</p>
<h2>Cancer and nanomedicine</h2>
<p>The potential of nanomedicine to improve a drug’s effectiveness and reduce its toxicity is attractive for cancer researchers working with anti-cancer drugs that often have strong side effects. Indeed, <a href="https://doi.org/10.1016/j.jconrel.2020.07.007">65% of clinical trials using nanoparticles</a> are focused on cancer.</p>
<p>The idea is that nanoparticle cancer drugs could <a href="https://doi.org/10.1021/acsnano.9b09713">act like biological missiles</a> that destroy tumors while minimizing damage to healthy organs. Because tumors have leaky blood vessels, researchers believe this would allow nanoparticles to <a href="https://dx.doi.org/10.1021%2Facs.bioconjchem.6b00437">accumulate in tumors</a>. Conversely, because nanoparticles can circulate in the bloodstream longer than traditional cancer treatments, they could accumulate less in healthy organs and reduce toxicity. </p>
<p>Although these design strategies have been successful in mouse models, most nanoparticle cancer drugs have <a href="https://doi.org/10.1021/acsnano.9b09713">not been shown</a> to be more effective than other cancer drugs. Furthermore, while some nanoparticle-based drugs can reduce toxicity to certain organs, they may increase toxicity in others. For example, while the nanoparticle-based <a href="https://doi.org/10.1007/s13577-012-0057-0">Doxil</a> decreases damage to the heart compared with other chemotherapy options, it can increase the risk of developing <a href="https://www.cancer.net/coping-with-cancer/physical-emotional-and-social-effects-cancer/managing-physical-side-effects/hand-foot-syndrome-or-palmar-plantar-erythrodysesthesia">hand-foot syndrome</a>.</p>
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<figcaption><span class="caption">The COVID-19 mRNA vaccines spurred excitement about nanoedicine’s potential applications to other diseases.</span></figcaption>
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<h2>Improving nanoparticle-based cancer drugs</h2>
<p>To investigate ways to improve how nanoparticle-based cancer drugs are designed, my research team and I <a href="https://doi.org/10.1016/j.biomaterials.2021.120910">examined how well</a> five approved nanoparticle-based cancer drugs accumulate in tumors and avoid healthy cells compared with the same cancer drugs without nanoparticles. Based on the findings of our lab study, we proposed that designing nanoparticles to be <a href="https://doi.org/10.1021/acsnano.9b09713">more specific</a> to their intended target could improve their translation from animal models to people. This includes creating nanoparticles that address the shortcomings of a particular drug – such as common side effects – and home in on the types of cells they should be targeting in each particular cancer type.</p>
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<p>Using these criteria, we designed a <a href="https://www.science.org/doi/10.1126/scitranslmed.abl3649">nanoparticle-based immunotherapy</a> for metastatic breast cancer. We first identified that breast cancer has a type of immune cell that suppresses immune response, helping the cancer become resistant to treatments that stimulate the immune system to attack tumors. We hypothesized that while drugs could overcome this resistance, they are unable to sufficiently accumulate in these cells to succeed. So we designed nanoparticles made of a common protein called albumin that could deliver cancer drugs directly to where these immune-suppressing cells are located.</p>
<p>When we tested our nanoparticle-based treatment on mice genetically modified to have breast cancer, we were able to eliminate the tumor and achieve complete remission. All of the mice were still alive 200 days after birth. We’re hopeful it will eventually translate from animal models to cancer patients.</p>
<h2>Nanomedicine’s bright but realistic future</h2>
<p>The success of some drugs that use nanoparticles, such as the <a href="https://doi.org/10.1038/d41586-021-02483-w">COVID-19 mRNA vaccines</a>, has prompted excitement among researchers and the public about their potential use in treating various other diseases, including talks about a future <a href="https://doi.org/10.1038/d41573-021-00110-x">cancer vaccine</a>. However, a vaccine for an infectious disease is <a href="https://doi.org/10.1186/s12943-021-01335-5">not the same</a> as a vaccine for cancer. Cancer vaccines may require different strategies to overcome treatment resistance. Injecting a nanoparticle-based vaccine into the bloodstream also has different design challenges than injecting into muscle.</p>
<p>While the field of nanomedicine has made good progress in getting drugs or diagnostics out of the lab and into the clinic, it still has a long road ahead. Learning from past successes and failures can help researchers develop breakthroughs that allow nanomedicine to live up to its promise.</p><img src="https://counter.theconversation.com/content/180009/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Duxin Sun receives funding from NIH, FDA and Pharmaceutical Industries for his lab research at The University of Michigan. </span></em></p>The COVID-19 mRNA vaccines put nanomedicine in the spotlight as a potential way to treat diseases like cancer and HIV. While the field isn’t there yet, better design could help fulfill its promise.Duxin Sun, Professor of Pharmaceutical Sciences, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1368312020-04-22T18:45:02Z2020-04-22T18:45:02ZA smart second skin gets all the power it needs from sweat<p><em>The Research Brief is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>Skin is the largest organ of the human body. It conveys a lot of information, including temperature, pressure, pleasure and pain. Electronic skin (e-skin) mimics the properties of biological skin. Recently developed e-skins are capable of wirelessly monitoring physiological signals. They could play a crucial role in the next generation of robotics and medical devices. </p>
<p><a href="http://www.gao.caltech.edu/">My lab at Caltech</a> is interested in studying human biology and monitoring human health by using advanced bioelectronic devices. The e-skin we have developed not only analyzes the chemical and molecular composition of human sweat, it’s <a href="http://robotics.sciencemag.org/lookup/doi/10.1126/scirobotics.aaz7946">fully powered by chemicals in sweat</a>.</p>
<h2>Why it matters</h2>
<p>Existing e-skins and wearable devices primarily focus on monitoring physiological parameters like heart rate and can’t assess health information at the molecular level. Moreover, they typically require batteries to power them, and the batteries need to be recharged frequently.</p>
<p>Despite recent efforts to harvest energy from the human body, there are no reports of self-powered e-skins that are able to perform biosensing and transmit the information via standard Bluetooth wireless communications. This comes down to the lack of power efficiency. There is a need for a self-powered device that can continuously collect molecular as well as physical information and wirelessly transmit the information to other devices.</p>
<h2>How we do this work</h2>
<p>The approach we take to harvesting energy from the human body is based on biofuel cells. Fuel cells convert chemical energy to electricity. The biofuel cells we developed for our e-skin convert the lactic acid in human sweat to electricity. In addition to the biofuel cells, the e-skin contains biosensors that can analyze metabolic information like glucose, urea and pH levels, to monitor for diabetes, ischaemia another health conditions, as well as physical information like skin temperature. The e-skin, made of soft materials and attached to a person’s skin, performs real-time biosensing, powered solely by sweat.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=403&fit=crop&dpr=1 600w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=403&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=403&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=506&fit=crop&dpr=1 754w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=506&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/329621/original/file-20200422-82699-uzmg0b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=506&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The sweat-powered biofuel cells in this electronic skin provide enough electricity to power biological sensors and transmit the information wirelessly to other devices.</span>
<span class="attribution"><span class="source">Yu et al., Sci. Robot. 5, eaaz7946 (2020)</span></span>
</figcaption>
</figure>
<p>Previously developed wearable biofuel cells <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/elan.201600019">don’t produce a lot of power</a> and aren’t very stable. We greatly improved the power output and stability of the biofuel cells by using novel nanomaterials for the cell’s two electrodes. The cathode of our biofuel cell is composed of a mesh of carbon nanotubes decorated with nanoparticles containing platinum and cobalt. The anode is a nanocomposite material that contains an enzyme that breaks down lactic acid. </p>
<p>The biofuel cells can generate a continuous, stable output as high as several milliwatts per square centimeter over multiple days in human sweat. That’s enough to power the biosensors as well as wireless communication. We demonstrated our e-skin by monitoring glucose, pH, ammonium ions and urea levels in studies using human subjects. We also used our e-skin as a human-machine interface to control the motion of a robotic arm and a prosthetic leg.</p>
<h2>What’s next</h2>
<p>We plan to further improve the power output of the biofuel cells and integrate different biosensors. The development of fully self-powered e-skin opens the door to numerous robotic and wearable health care possibilities. Wearable sensor arrays could be used for health monitoring, early disease diagnosis and potentially nutritional intervention. In addition, self-powered e-skin could be used to design and optimize next generation prosthetics.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/136831/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Wei Gao receives funding from the National Institute of Health. </span></em></p>Lightweight, flexible materials can be used to make health-monitoring wearable devices, but powering the devices is a challenge. Using fuel cells instead of batteries could make the difference.Wei Gao, Assistant Professor of Medical Engineering, California Institute of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1311472020-02-11T19:08:45Z2020-02-11T19:08:45ZSmall world: atom-scale materials are the next tech frontier<figure><img src="https://images.theconversation.com/files/314662/original/file-20200211-146686-19pb781.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C7976%2C4500&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Could graphene - shown here as an illustration of its molecular structure - come to define the next phase of the information revolution?</span> <span class="attribution"><span class="source">Rost9/Shutterstock</span></span></figcaption></figure><p>Every age in the history of human civilisation has a signature material, from the Stone Age, to the Bronze and Iron Ages. We might even call today’s information-driven society the Silicon Age. </p>
<p>Since the 1960s, silicon <a href="https://www.sciencedirect.com/topics/engineering/silicon-nanoparticles">nanostructures</a>, the building-blocks of microchips, have supercharged the development of electronics, communications, manufacturing, medicine, and more.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-nanotechnology-is-more-than-just-a-buzzword-97376">Why nanotechnology is more than just a buzzword</a>
</strong>
</em>
</p>
<hr>
<p>How small are these nanostructures? Very, very small – you could fit <a href="https://www.extremetech.com/extreme/191996-zoom-into-a-computer-chip-watch-this-video-to-fully-appreciate-just-how-magical-modern-microchips-are">at least 3,000 silicon transistors onto the tip of a human hair</a>. But there is a limit: below about 5 nanometres (5 millionths of a millimetre), it is hard to improve the performance of silicon devices any further.</p>
<p>So if we are about to exhaust the potential of silicon nanomaterials, what will be our next signature material? That’s where “atomaterials” come in. </p>
<h2>What are atomaterials?</h2>
<p>“Atomaterials” is short for “atomic materials”, so called because their properties depend on the precise configuration of their atoms. It is a new but <a href="https://lniconference.com.au/">rapidly developing</a> field.</p>
<p>One example is <a href="https://theconversation.com/graphene-and-the-atomic-crystals-that-could-see-next-big-breakthrough-in-tech-99156">graphene</a>, which is made of carbon atoms. Unlike diamond, in which the carbon atoms form a rigid three-dimensional structure, graphene is made of single layer of carbon atoms, bonded together in a two-dimensional honeycomb lattice.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/harder-than-diamond-stronger-than-steel-super-conductor-graphenes-unreal-5123">Harder than diamond, stronger than steel, super conductor ... graphene's unreal </a>
</strong>
</em>
</p>
<hr>
<p>Diamond’s rigid structure is the reason for its celebrated hardness and longevity, making it the perfect material for high-end drill bits and expensive jewellery. In contrast, the two-dimensional form of carbon atoms in graphene allows electron travelling frictionless at a high speed giving ultrahigh conductivity and the outstanding in plane mechanical strength. Thus, graphene has broad applications in medicines, electronics, energy storage, light processing, and water filtration. </p>
<p>Using lasers, we can fashion these atomic structures into miniaturised devices with exceptional performance.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/JtmQi-eJQfg?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>Using atomaterials, <a href="https://www.swinburne.edu.au/research/translational-atomaterials/">our lab</a> has been working on a range of innovations, at various stages of development. They include:</p>
<ul>
<li><strong>A magic cooling film</strong>. This film can cool the environment by up to 10°C without using any electricity. By integrating such a film into a building, the electricity used for air conditioning can be reduced by 35%, and summer electricity blackouts effectively stopped. This will not only save electricity bills but also reduce greenhouse emissions.</li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/314664/original/file-20200211-146700-cz8xg2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Baohua Jia and Han Lin with the graphene cooling film.</span>
<span class="attribution"><span class="source">CTAM Global OpenLab</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<ul>
<li><strong>Heat-absorbing film</strong>. Some 97% of Earth’s water is in the oceans, and is salty and unusable without expensive processing. Efficiently removing salt from seawater could be a long-term solution to the growing global freshwater scarcity. With a solar-powered graphene film, this process can be made very efficient.</li>
</ul>
<p>The film absorbs almost all the sunlight shining on it and converts it into heat. The temperature can be <a href="https://www.sustainabilitymatters.net.au/content/energy/case-study/ultrathin-graphene-film-offers-new-concept-for-solar-energy-738586419">increased to 160°C within 30 seconds</a>. This heat can then distil seawater with an efficiency greater than 95%, and the distilled water is cleaner than tapwater. This low-cost technology can be suitable for domestic and industry applications.</p>
<ul>
<li><p><strong>Smart sensing film</strong>. These flexible atomaterial films can incorporate a wide range of functions including environmental sensing, communication, and energy storage. They have a broad range of applications in healthcare, sports, advanced manufacturing, farming, and others. For example, smart films could monitor soil humidity near plants’ roots, thus helping to make agriculture more water-efficient.</p></li>
<li><p><strong>Ultrathin, ultra-lightweight lenses</strong>. The bulkiest part of a mobile phone camera is the lens, because it needs to be made of thick glass with particular optical properties. But lenses made with graphene can be mere <a href="https://newatlas.com/optical-lens-one-billionth-meter-thick/41588/">millionths of a millimetre thick</a>, and still deliver superb image quality. Such lenses could greatly reduce the weight and cost of everything from phones to space satellites. </p></li>
<li><p><strong>Near-instant power supply</strong>. We have developed an environmentally friendly supercapacitor from graphene that <a href="https://freshscience.org.au/2016/fast-charging-everlasting-battery-power-from-graphene">charges devices in seconds</a>, and has a lifetime of millions of charge cycles. By attaching it to the back of a solar cell, it can store and deliver solar-generated energy whenever and wherever required. You will be free and truly mobile.</p></li>
</ul>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/314665/original/file-20200211-146678-1lakcot.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The graphene supercapacitor could help mobile power truly live up to its name.</span>
<span class="attribution"><span class="source">CTAM Global OpenLab</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Where to next?</h2>
<p>It can take years for some of these laboratory technologies to reach fruition. To try and speed up the process, we established the <a href="https://ctam.org.au/about-ctam/">CTAM Global OpenLab</a> to engage with industry, academia, government and the wider community and to promote sharing and collaboration. The lab was launched earlier this month at the <a href="https://lniconference.com.au/">International Conference on Nanomaterial and Atomaterial Sciences and Applications (ICNASA2020)</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/finding-an-affordable-way-to-use-graphene-is-the-key-to-its-success-32154">Finding an affordable way to use graphene is the key to its success</a>
</strong>
</em>
</p>
<hr>
<p>The world is facing pressing challenges, from climate change, to energy and resource scarcity, to our health and well-being.</p>
<p>Material innovation is more vital than ever and needs to be more efficient, design-driven and environmentally friendly. But these challenges can only be solved by joint effort from worldwide researchers, enterprise, industry and government with a sharing and open mindset.</p><img src="https://counter.theconversation.com/content/131147/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Baohua Jia receives funding from Australian Research Council, Cooperative Research Centres Projects. She is affiliated with Centre for Translational Atomaterials (CTAM), Faculty of Science, Engineering and Technology, Swinburne University of Technology. </span></em></p>Since the 1960s, silicon ‘nanomaterials’ have driven the information revolution. But as their potential is exhausted, is it time for ‘atomaterials’ such as graphene to drive innovation still further?Baohua Jia, Professor, Swinburne University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1088632019-01-22T21:27:40Z2019-01-22T21:27:40ZFreshwater wildlife face an uncertain future<figure><img src="https://images.theconversation.com/files/254429/original/file-20190117-32828-180ls8v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spawning sockeye salmon make their way up the Adams River near Chase, B.C.</span> <span class="attribution"><span class="source">THE CANADIAN PRESS/Jonathan Hayward</span></span></figcaption></figure><p>Pacific salmon are one of Canada’s iconic creatures. Each summer, they complete their, on average, four- to five-year-long life cycle by returning from their rich ocean feeding grounds to the creeks and streams where they were born. Here, following in the “footsteps” of their parents, they will lay eggs, die and give rise to the next generation of salmon.</p>
<p>This transit from freshwater to the sea and back again is sometimes thousands of kilometres long. It can also be treacherous — the fish must navigate steep river rapids and avoid voracious predators. </p>
<p>But the trek is only being made harder by unnatural challenges. Humans continue to dam and pollute rivers, overfish and introduce invasive plants and animals. And this is just the tip of the iceberg in terms of how humans are profoundly reshaping fresh waters in Canada and around the world.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/254424/original/file-20190117-32813-n3zgre.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Salmon eggs lie among the rocks in the Adams River, B.C.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>For <a href="http://www.fecpl.ca/">our research on</a> the migration and conservation of Pacific salmon, we have looked at how freshwater ecosystems — lakes, rivers, streams and wetlands — are changing around the globe. Society has <a href="https://theconversation.com/global/topics/marine-conservation-3200">its finger on the pulse of the oceans</a>, but what about our too often forgotten fresh waters?</p>
<h2>Lakes and rivers in crisis</h2>
<p>While fresh waters make up just a fraction (<a href="https://www.sciencedirect.com/science/article/pii/S0022169404001404">0.01 per cent</a>) of all the water on the planet, they are home to nearly <a href="https://link.springer.com/chapter/10.1007%2F978-1-4020-8259-7_61">10 per cent of the Earth’s known animal species</a>, including one third of all vertebrates (anything with a backbone). There are even <a href="https://royalsocietypublishing.org/doi/full/10.1098/rspb.2012.0075">more species of fish</a> in freshwater ecosystems than there are in the ocean.</p>
<p>This picture is, sadly, changing quickly. The World Wide Fund for Nature (WWF) recently published the “<a href="https://wwf.panda.org/knowledge_hub/all_publications/living_planet_report_2018/">Living Planet Report 2018</a>,” showing that freshwater species loss is more severe than species declines on land or in the ocean.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=383&fit=crop&dpr=1 600w, https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=383&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=383&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=481&fit=crop&dpr=1 754w, https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=481&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/254041/original/file-20190116-152995-foq1md.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=481&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The WWF Living Planet Report reveals remarkable decreases for freshwater species.</span>
<span class="attribution"><span class="source">Modified from Reid et al. 2018</span></span>
</figcaption>
</figure>
<p>Alarmingly, populations of freshwater species on average have declined by more than 80 per cent in 50 years, while populations of land-dwellers and ocean creatures have fallen by less than half that.</p>
<p>Clearly, fresh waters are in crisis with worsening trends over the past decade. But why?</p>
<h2>Threats: The dirty dozen</h2>
<p>Scientists know that damming, polluting, overfishing and introducing new species are changing “waterscapes” around the world, and impeding the survival of animals like Pacific salmon. We have known about these threats to freshwater biodiversity <a href="https://doi.org/10.1017/S1464793105006950">for at least a dozen years</a>.</p>
<p>But a lot can change in 12 years — and it has. With an international team of some of the world’s leading freshwater scientists, <a href="https://doi.org/10.1111/brv.12480">our new study</a> documents a dozen threats — some new, some growing — to freshwater species:</p>
<ol>
<li> A rapidly changing climate</li>
<li> Online wildlife trade and invasive species </li>
<li> Infectious disease</li>
<li> Toxic algae blooms </li>
<li> Hydropower damming and fragmenting of half the world’s rivers</li>
<li> Emerging contaminants, such as hormones </li>
<li> Engineered nanomaterials </li>
<li> Microplastic pollution </li>
<li> Light and noise interference</li>
<li>Saltier coastal freshwaters due to sea level rise</li>
<li>Calcium concentrations falling below the needs of some freshwater organisms</li>
<li>The additive — and possibly synergistic — effects of these threats</li>
</ol>
<p>Our team fears that fresh waters continue to be overlooked. These mounting threats and rapid species losses are taking place below the water’s surface — out of sight and out of mind.</p>
<p>“This is a silent, invisible tragedy that attracts far too little interest,” said <a href="https://www.cardiff.ac.uk/people/view/81244-ormerod-steve">Steve Ormerod</a>, a freshwater ecologist from Cardiff University, in Wales, U.K., and one of our team members. </p>
<p>We hope to change this narrative by drawing attention to these 12 critical threats.</p>
<p>We need action on these threats — now. </p>
<h2>Hope on the horizon?</h2>
<p>This is a lot to take in. It may feel like there are no solutions that will change the trajectory for freshwater species. Fortunately, that is not the case and we highlight opportunities for conservation gains.</p>
<p>New scientific tools are changing the way we monitor freshwater populations. <a href="https://theconversation.com/we-need-a-bank-of-dna-from-dirt-and-water-to-protect-australias-environment-98633">Environmental DNA</a>, for example, may soon allow us to use a single water sample to identify all the fish in a watershed — without ever seeing the species.</p>
<p>Other approaches, including the use of “environmental flows” (e-flows) to manage the flow of water below a dam, dam removal as well as fishways let fish like Pacific salmon circumnavigate some of the barriers we have created.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/254031/original/file-20190116-152992-hjgmkd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Chum salmon spawned out in Fish Creek, Alaska.</span>
<span class="attribution"><span class="source">Andrea Reid</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>But the solution does not rest solely with technological advancements to reverse past errors. We need to meet the freshwater needs of both people and nature by changing the way we treat fresh waters, for example, through our <a href="https://www.nationalgeographic.com/environment/freshwater/top-ten/">day-to-day actions</a>, by joining or supporting the <a href="https://allianceforfreshwaterlife.org/">Alliance for Freshwater Life</a> and pressing our governments to join the <a href="https://www.cbd.int/sp/targets/">global effort</a> to preserve freshwater.</p><img src="https://counter.theconversation.com/content/108863/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrea Jane Reid receives funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) and other funders including the National Geographic Society and the Royal Canadian Geographical Society. As a member of the Nisga'a Nation, she also receives support from the Nisga'a Lisims Government. She is affiliated with InFish and is a Fellow of The Explorer's Club.</span></em></p><p class="fine-print"><em><span>Steven J Cooke receives funding from the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs Program, and other various funders (such as Fisheries and Oceans Canada). He is affiliated with InFish and is a Member of the College of the Royal Society of Canada.</span></em></p>Populations of freshwater species are in a state of deep decline. But we know why and we can reverse the trend.Andrea Reid, PhD Candidate, Carleton UniversitySteven J Cooke, Canada Research Chair & Professor, Carleton UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1017482019-01-10T10:48:12Z2019-01-10T10:48:12ZNanomaterials are changing the world – but we still don’t have adequate safety tests for them<figure><img src="https://images.theconversation.com/files/253083/original/file-20190109-32133-j3c91k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/scientists-certain-activities-on-experimental-science-506591185?src=OziWc7SFEXplQ2IRwvKOvA-1-1">joker1991/Shutterstock</a></span></figcaption></figure><p>Nanotechnology may well be one of the most talked about industries of the last few years. Predicted <a href="https://www.prnewswire.com/news-releases/global-nanotechnology-market-analysis--trends---industry-forecast-to-2025-300340182.html">to value US$173.95 billion</a> globally by 2025, this fast-moving sector is <a href="https://theconversation.com/five-ways-nanotechnology-is-securing-your-future-55254">already delivering</a> major sustainability, health and well-being benefits to society. </p>
<p>Nanomaterials, as the name suggests, are very small, less than a millionth of a metre in size. They have unique physical and chemical features which give them improved properties such as greater reactivity, strength, electrical characteristics and functionality. These benefits have resulted in nanomaterials being incorporated into <a href="http://www.nanotechproject.org/cpi/">a wide range of consumer products</a>. The automotive, computing, electronic, cosmetics, sports and healthcare industries all benefit from nanotechnology innovations. New fields have also emerged, such as nanomedicine, which aims to dramatically improve our future ability to treat disease. </p>
<p>But exciting as this may sound, as with any innovation, we must ensure that human health and environmental impacts are considered. And this is not a simple task. Although standard hazard assessments are available for a wide range of things – such as chemical compounds – nanomaterials have unique properties so cannot be evaluated in exactly the same way.</p>
<h2>Environmental health and humans</h2>
<p>Nanomaterials are already entering our environment, albeit at low levels. They are being found in <a href="https://link.springer.com/article/10.1007/s11270-017-3656-2#Sec23">waste water</a> from products like <a href="https://www.theguardian.com/what-is-nano/small-world/nanotechnology-in-your-toothpaste">toothpaste</a>, <a href="https://www.independent.co.uk/environment/sunscreen-pollution-beaches-toxic-marine-life-fish-france-titanium-dioxide-tio2-a8496426.html">sun lotion</a>, and when items such as <a href="https://theconversation.com/silver-nanoparticles-in-clothing-wash-out-and-may-threaten-human-health-and-the-environment-90309">nano-silver socks</a> (which prevent smelly feet) are washed. Short-term environmental safety studies have also found that <a href="https://setac.onlinelibrary.wiley.com/doi/10.1002/etc.3385">many nanomaterials adsorb</a> (form a thin film) on the surface of organisms’ – such as algae and water fleas – epidermis. The materials are also distributed in both gut systems and throughout small creatures’ bodies. </p>
<p>It is vitally important we get to grips with the potential adverse impacts of nanomaterials before widespread environmental dispersion occurs. At present, the long-term effects of nanomaterial exposure on ecosystems is poorly understood. Nor do we know the impact of nanomaterial exposure on the food chain. They could affect feeding rates as well as the behaviour and survival of different species, for example. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/MkpcUpattE8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>We also don’t know enough about how nanomaterials can affect humans when exposed in small doses and over long periods. The most important routes of exposure for humans are the lungs, gut and skin. Nanomaterials are being incorporated into <a href="https://theconversation.com/nanotechnology-could-make-our-food-tastier-and-healthier-but-can-we-stomach-it-60349">food products</a> and <a href="https://link.springer.com/article/10.1007/s13197-018-3266-z">packaging</a>, and they may be inhaled or swallowed by workers during manufacturing, too. Tests have shown that once nanomaterials enter the body they become <a href="https://www.tandfonline.com/doi/full/10.1080/17435390.2017.1306894">trapped in the liver</a>, but we don’t know what risk they pose long term.</p>
<p>The current standard non-animal safety tests for human lung, gut and skin exposure are very simplistic. For example, to determine the biological impact of inhaling nanomaterials, scientists grow a single lung cell system in the lab and expose it to nanomaterials suspended in liquid. But there are over 40 different cell types within the human lung. These kinds of tests cannot accurately predict the potential harm associated with nanomaterial exposure. Nor accurately mimic the complexity of the human body or the manner in which we encounter nanomaterials. </p>
<h2>The next generation</h2>
<p>The world has already experienced the problems that can come with new innovations. Given the world’s experiences with <a href="http://jtd.amegroups.com/article/view/17002/html">asbestos</a> (which, though having been used for thousands of years, was only discovered as a source of diseases in the 1900s), the controversial development of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4576180/">genetically modified foods</a>, and the highly topical <a href="https://www.nationalgeographic.com/magazine/2018/06/plastic-planet-waste-pollution-trash-crisis/">microplastics crisis</a>, it is imperative that advances in nanotechnology do not result in similar health crises. </p>
<p>Our research team is now working to improve nanotechnology tests, through the Horizon 2020-funded project <a href="https://www.patrols-h2020.eu">PATROLS</a>. Bringing together leading international nanosafety, ecotoxicology, tissue engineering and computational modelling experts from all over the world, our aim is to build on international best practice and address the current testing limitations.</p>
<p>We are already adopting cutting-edge science to develop advanced tissue models of the lung, gut and liver for nanomaterial safety assessment. We’re working on new safety assessment methods for environmentally relevant test systems and organisms (including algae, water fleas and zebrafish), which have been selected according to their position in the food chain. These next generation, non-animal tests are aimed at reducing the reliance on animal testing, too, while promoting the responsible development of the nanotechnology industry. </p>
<p>In addition, we are working to create a way of predicting human and environmental nanomaterial safety based on computational models. This will allow screening of new nanomaterials using a computer database as an initial safety check before further testing is carried out.</p>
<p>By improving non-animal tests for nanotechnology, we can help protect consumers, workers and the environment from any health or safety risks that they would potentially cause. Nanotechnology has already shown that it can enhance our lives, and with an improved understanding of their safety, we can more confidently enjoy the benefits this new technology offers.</p><img src="https://counter.theconversation.com/content/101748/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shareen Doak receives funding from the European Commission, Unilever and NC3Rs. This article was written with input from PATROLS project manager Kevin Fernquest.</span></em></p><p class="fine-print"><em><span>Martina G. Vijver receives funding from EU Horzon2020 PATROLS. </span></em></p><p class="fine-print"><em><span>Martin Clift receives funding from Welsh Government and Unilever. </span></em></p>Nanotechnology and materials are the source of countless innovations, but we don’t accurately know how they are affecting humans and the environment.Shareen Doak, Professor of Genotoxicology and Cancer, Swansea UniversityMartina G. Vijver, Professor of Ecotoxicology, Leiden UniversityMartin Clift, Senior Lecturer, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1036372018-09-21T18:07:15Z2018-09-21T18:07:15ZSpray-on antennas unlock communication of the future<figure><img src="https://images.theconversation.com/files/237496/original/file-20180921-129856-hkb2qo.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Spraying an antenna onto a flat surface.</span> <span class="attribution"><span class="source">Drexel University Nanomaterials Lab</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Hear the word “antenna” and you might think about rabbit ears on the top of an old TV or the wire that picks up radio signals for a car. But an antenna can be much smaller – even invisible. No matter its shape or size, an antenna is crucial for communication, transmitting and receiving radio signals between devices. As portable electronics become increasingly common, antennas must, too.</p>
<p>Wearable monitors, flexible smart clothes, industrial sensors and medical sensors will be much more effective if their antennas are lightweight and flexible – and possibly even transparent. We and our collaborators have developed a type of material that offers many more options for connecting antennas to devices – including <a href="http://doi.org/10.1126/sciadv.aau0920">spray-painting them on walls or clothes</a>.</p>
<p>Our <a href="http://nano.materials.drexel.edu/">materials science lab</a> focuses on nanomaterials, which are more <a href="https://www.niehs.nih.gov/health/topics/agents/sya-nano/index.cfm">than 100,000 times thinner</a> than a human hair. In 2011, researchers in the Drexel University Materials Science and Engineering Department developed a way to combine metals with carbon or nitrogen atoms to create a material that’s a few atoms thick, very strong and good at conducting electricity. We call <a href="https://doi.org/10.1002/adma.201102306">these materials MXenes</a> (pronounced “maksens”), and we can make them with different metals – including titanium, molybdenum, vanadium and niobium.</p>
<p><a href="https://scholar.google.com/citations?user=Tobmw7EAAAAJ&hl=en">Our</a> <a href="https://scholar.google.com/citations?user=M6wPYpAAAAAJ&hl=en">most</a> <a href="https://scholar.google.com/citations?user=JNCaAWkAAAAJ&hl=en">recent</a> work has identified that mixing MXenes with water lets us spray antennas on any surface, including a brick wall or a glass window – and even use an inkjet to <a href="https://doi.org/10.1002/admt.201800256">print an antenna on paper</a>. This creates new opportunities for smaller, lighter, more flexible antennas to accompany devices that are also being made from <a href="https://theconversation.com/paper-based-electronics-could-fold-biodegrade-and-be-the-basis-for-the-next-generation-of-devices-102759">more varied and versatile materials</a>.</p>
<h2>Antennas aren’t quite everywhere – yet</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=803&fit=crop&dpr=1 600w, https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=803&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=803&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1009&fit=crop&dpr=1 754w, https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1009&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/237492/original/file-20180921-129856-1nfqwy0.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1009&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researcher Asia Sarycheva holds up an MXene antenna.</span>
<span class="attribution"><span class="source">Drexel University Nanomaterials Group</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Smart watches and electronic car key fobs might seem advanced, but researchers are working on many more options, including hospital gowns that can sense patients’ heart and breathing rates, and <a href="https://theconversation.com/the-next-frontier-in-medical-sensing-threads-coated-in-nanomaterials-60597">stitches that monitor healing after surgery</a>. They’ll need antennas too – which are sterile, <a href="https://theconversation.com/embroidering-electronics-into-the-next-generation-of-smart-fabrics-91791">flexible</a>, strong and even machine-washable.</p>
<p>Another type of antenna is making its way into the world, too. Many <a href="https://www.npr.org/sections/alltechconsidered/2017/07/04/535518514/there-are-plenty-of-rfid-blocking-products-but-do-you-need-them">credit and debit cards</a>, as well as <a href="https://travel.state.gov/content/travel/en/passports/apply-renew-passport/faqs.html">U.S. passports</a>, contain what are called RFID tags, tiny electronic chips that carry identifying information and transmit them to sensors that validate transactions or certify the identity of the document’s carrier. </p>
<p>RFID tags are even more commonly used in industry, <a href="https://www.marketwatch.com/press-release/rfid-technology-market-worth-405-billion-by-2025-cagr-147-grand-view-research-inc-2017-05-16-72033111">tracking components in manufacturing processes</a>, individual boxes and containers in large shipments and even <a href="https://www.marketwatch.com/press-release/airport-radio-frequency-identification-rfid-system-market-2018-highlights-by-competitive-scenario-with-impact-of-new-innovations-drivers-and-challenges-to-2023-2018-09-20">controlling workers’ access</a> to specific areas of an office or factory.</p>
<h2>A wide range of uses</h2>
<p>Since Drexel’s 2011 <a href="http://max.materials.drexel.edu/research-areas/mxene/">discovery of MXenes</a>, researchers around the world have been testing out how they work in a variety of tasks. Some early successes have included <a href="http://drexel.edu/now/archive/2017/July/MXene-electrode/">energy storage devices</a>, <a href="https://www.youtube.com/watch?v=q41ajeI5qQw">electromagnetic interference shielding</a>, <a href="http://doi.org/10.1021/acs.jpclett.5b01895">water filtration</a>, <a href="http://drexel.edu/now/archive/2018/February/MXene-gas-sensor/">chemical sensing</a>, <a href="http://drexel.edu/now/archive/2018/June/mxene-ceramic-cold-sintering/">structural reinforcement</a>, <a href="https://doi.org/10.1021/acs.nanolett.6b04339">cancer treatment</a> and <a href="http://drexel.edu/now/archive/2018/January/MXene-material-gas-separation/">gas separation</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/q41ajeI5qQw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">How MXenes can shield electromagnetic radiation.</span></figcaption>
</figure>
<p>All of these approaches take advantage of the physical and electrical properties of MXenes: They’re transparent to light, electronically conductive, chemically stable and strong.</p>
<h2>Simple spraying</h2>
<p>We have been exploring how to use another physical attribute MXenes have: They love water. When we mix sheets of two-dimensional titanium carbide MXene with water, we get a stable water-based ink. We can spray or print that ink on any surface, and when the water evaporates, what’s left behind is layers of MXene – an MXene antenna. </p>
<p>When we do this with a titanium carbide MXene, the resulting antenna is very good at transmitting and directing radio waves, even when it’s applied in a very thin layer. Our initial testing suggests it can perform as well as more commonly used antennas made of gold, silver, copper or aluminum. And because it’s so much thinner, an MXene antenna can be effective in spaces too small for other antenna materials – even as small as one-thousandth the thickness of a sheet of paper. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/-sAyDJeuVBE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Spraying MXene antennas on surfaces.</span></figcaption>
</figure>
<h2>Comparing to other antennas</h2>
<p>When we made MXene antennas slightly thicker – more like one-tenth the thickness of a piece of paper – it could still outperform antennas made of other high-tech nanomaterial-based antennas, including <a href="https://doi.org/10.1038/nnano.2009.355">carbon nanotubes</a>, <a href="https://doi.org/10.1088/2053-1583/3/2/025021">graphene</a> and <a href="http://dx.doi.org/10.1049/iet-map.2013.0076">nano-silver ink</a>.</p>
<p>In addition, the MXene antennas were far easier to make. Other nanomaterials fabrication processes require mixing the electronically capable ingredients with other materials to help them stick to each other, and heating them all together to strengthen their interconnections. Our MXene antennas are made in two steps: Mix the MXenes with water, and spray it on with an airbrush.</p>
<p>This means antennas could be airbrush-sprayed almost anywhere, by almost anyone, for nearly any purpose. This new material type opens a wide range of new possibilities for electronic devices that can be anywhere and still communicate effectively.</p><img src="https://counter.theconversation.com/content/103637/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yury Gogotsi is affiliated with the Materials Research Society (Board of Directors) and Jilin University (Distinguished Foreign Professor)</span></em></p><p class="fine-print"><em><span>Asia Sarycheva and Babak Anasori do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new type of material can make it easy to put antennas almost anywhere – no matter how thin the space, or even on surfaces people need to be able to see through.Yury Gogotsi, Professor of Materials Science and Engineering, Drexel UniversityAsia Sarycheva, Ph.D. Student in Materials Science and Engineering, Drexel UniversityBabak Anasori, Research Assistant Professor of Materials Science and Engineering, Drexel UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/897262018-04-23T10:40:48Z2018-04-23T10:40:48ZDelivering VR in perfect focus with nanostructure meta-lenses<figure><img src="https://images.theconversation.com/files/213474/original/file-20180405-189824-cn6r37.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Could there be a future with smaller, less bulky VR headsets?</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Innovation-Day-USA-2018/34b2f157d4c241879634f9abf5309858/1/0">Jean-Marc Giboux/AP Images for Siemens</a></span></figcaption></figure><p>If wearing a virtual reality or augmented reality headset is ever to become commonplace, hardware manufacturers will need to figure out how to make the devices small and lightweight while ensuring their images are sharp and clear. Unfortunately, this task faces a key limitation in optics: Conventional lenses are curved glass objects that focus different wavelengths of light in different locations, which would show viewers blurry images. As a result, pretty much anything with a lens – from tiny smartphone cameras to large-scale projectors – uses multiple lenses, which add weight, thickness and complexity, increasing cost.</p>
<p>We’ve figured out a <a href="http://doi.org/10.1038/s41565-017-0034-6">new way to manufacture fully transparent, ultracompact lenses</a> capable of properly focusing every color in the spectrum to the same point. Because our lens comprises specially designed nanostructures, which do not exist in nature, to focus light, we call it a “meta-lens.” It has the advantages of being ultracompact while capable of delivering higher-quality imaging across a wider spectrum of light than most traditional lenses, without requiring multiple lenses.</p>
<h2>Bending light</h2>
<p>For centuries, most lenses for telescopes, glasses and <a href="https://www.nikoninstruments.com/Learn-Explore/Nikon-Craftsmanship/Lens-Polishing-Hand-polishing-spherical-front-lenses-for-microscopes">other optical equipment have been manufactured</a> by grinding glass into a rough curved shape and then polishing it to cleanly and clearly bend light. However, these lenses can’t focus light of every color on the same point.</p>
<p>It is a basic property of light that different colors – or frequencies – travel at different speeds in a lens. They cannot reach the same point at the same time, resulting in blurred images.</p>
<figure>
<img src="https://cdn.theconversation.com/static_files/files/72/Light_dispersion_conceptual_waves.gif?1522955022">
<figcaption><span class="caption">Different frequencies of light bend and travel differently in a lens. <a href="https://commons.wikimedia.org/wiki/File:Light_dispersion_conceptual_waves.gif">Lucas V. Barbosa</a></span></figcaption>
</figure>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=334&fit=crop&dpr=1 600w, https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=334&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=334&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=419&fit=crop&dpr=1 754w, https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=419&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/213469/original/file-20180405-189804-14rz8tv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=419&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Even a smartphone camera has many intricate components layered together.</span>
<span class="attribution"><a class="source" href="http://laptopmedia.com/smartphone-review/apple-iphone-6-review-the-phone-weve-been-expecting-for-years/#camera">Laptop Media</a></span>
</figcaption>
</figure>
<p>To reduce this effect, commercial lens manufacturers construct complicated optical devices with many separate lenses, each precisely ground into curves and aligned to focus its range of wavelengths in just the right place. However, they end up with large, heavy and complex lenses – nothing that would be easy to wear comfortably as part of a VR experience.</p>
<h2>The power of nanostructures</h2>
<p>To replace these enormous and expensive precision-engineered products, we start with a millimeter-thick sheet of regular flat glass. On it, we place a layer of carefully designed rectangular nanostructures, a million times thinner than the glass layer, made of titanium dioxide, which is totally transparent to visible light.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/215280/original/file-20180417-163971-zzlzp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The nanonstructures as viewed by a scanning electron microscope.</span>
<span class="attribution"><a class="source" href="https://www.seas.harvard.edu/capasso/">Capasso Group, Harvard University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The nanostructures are designed to bend incoming light rays by increasingly greater angles the farther they hit the meta-lens from its center so that all rays are focused in the same spot. To secure the nanostructures onto the glass substrate, we use <a href="https://www.bloomberg.com/news/articles/2016-06-09/how-intel-makes-a-chip">lithography</a>, a technique widely used to mass-produce computer chips.</p>
<p>In 2016, we showed that using flat glass with nanostructures could <a href="https://doi.org/10.1126/science.aaf6644">focus light of one specific color</a> just as well as a traditional curved lens. But in that research, what we made suffered from the same age-old problem as curved glass: Each color focused on a different location. To have our flat lenses form high-quality images, all the light – regardless of its color – must focus on the same point.</p>
<h2>Including all colors</h2>
<p>In our latest work, we design a more sophisticated set of nanostructures, which even on a flat surface can do much more than a traditional curved lens. The nanostructures still bend the light at higher angles the farther from the center they are, but with an important modification inspired by a key insight. After leaving the meta-lens, the light has to travel to the focus point, which is farther from the edges than it is from the center of the lens. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=789&fit=crop&dpr=1 600w, https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=789&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=789&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=992&fit=crop&dpr=1 754w, https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=992&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/215281/original/file-20180417-163978-tf7nzk.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=992&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A diagram of how a meta-lens can focus all colors of light on a single point.</span>
<span class="attribution"><a class="source" href="https://www.seas.harvard.edu/capasso/">Capasso Group, Harvard University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>To travel a longer distance in the same period of time, that light has to travel faster. So we built some nanostructures that transmit the light more quickly, and others that do so more slowly. We put the faster-transmitting nanostructures at the edges of the lens, so <a href="http://doi.org/10.1038/s41565-017-0034-6">light travels through them faster</a> than in those in the middle. This effectively helps the light from the meta-lens edges catch up with light at the center, so that all the rays focus together.</p>
<p>This approach can be modified for any number of specialized situations, allowing construction of meta-lenses that have a wide range of properties, such as the ability to affect certain colors but not others: A custom-designed nanostructure can make that adjustment relatively simply, without the constraints or complexities of polishing curved glass lenses to highly precise specifications.</p>
<p>Once designed, meta-lenses can be created as part of a wider mass production process: for instance, of VR headsets or augmented reality glasses. They can also be used in place of more expensive ground-glass camera lenses on smartphones and laptops, reducing weight, thickness and cost of portable devices.</p>
<p>It may seem surprising that the centuries-old challenge of multi-color focusing can be solved by a thin piece of glass underneath nanostructures barely visible to the human eye. But indeed, the meta-lens approach can provide what all those bulky traditional lenses cannot: a clear image across a broad range of colors.</p><img src="https://counter.theconversation.com/content/89726/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Federico Capasso owns shares in and is a board member of a startup, METALENZ, which he co-founded in 2015. The research described in this article is funded in part by the Air Force Office of Scientific Research and DARPA.</span></em></p><p class="fine-print"><em><span>Alexander Yutong Zhu and Wei-Ting Chen do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Using nanostructures on a flat piece of glass can make lenses smaller, lighter and much cheaper – while providing better image quality.Federico Capasso, Professor of Applied Physics, Senior Research Fellow in Electrical Engineering, Harvard UniversityAlexander Yutong Zhu, Ph.D. Candidate in Applied Physics, Harvard UniversityWei-Ting Chen, Postdoctoral Fellow in Applied Physics, Harvard UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/935232018-03-20T10:42:01Z2018-03-20T10:42:01ZEager to dye your hair with ‘nontoxic’ graphene nanoparticles? Not so fast!<figure><img src="https://images.theconversation.com/files/211082/original/file-20180319-31624-18d3y07.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Subbing new risks for the current dyes’ dangers?</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/hairdresser-salon-woman-during-hair-wash-1044886945">Evgeny Savchenko/Shutterstock.com</a></span></figcaption></figure><p>Graphene is something of a celebrity in the world of nanoscale materials. Isolated in 2004 by Nobel Prize winners <a href="https://www.nobelprize.org/nobel_prizes/physics/laureates/2010/">Andre Geim and Konstantin Novoselov</a>, these ultrathin sheets of carbon atoms are already finding novel uses in areas like <a href="https://www.nist.gov/programs-projects/graphene-electronics">electronics</a>, <a href="https://spectrum.ieee.org/nanoclast/green-tech/conservation/graphene-heating-system-dramatically-reduces-home-energy-costs">high-efficiency heating systems</a>, <a href="https://www.ft.com/content/d768030e-d8ec-11e7-9504-59efdb70e12f">water purification technologies</a> and <a href="http://cmp.callawaygolf.com/2018/01/23/chrome-soft-golf-balls-need-know/">even golf balls</a>. According to recent research published in the journal Chem, <a href="https://doi.org/10.1016/j.chempr.2018.02.021">hair dyes can now be added to this list</a>. </p>
<p>But how safe and responsible is this new use of the carbon-based wonder-material?</p>
<p>Northwestern University’s <a href="https://www.eurekalert.org/pub_releases/2018-03/nu-gfn031218.php">press release</a> proudly announced, “Graphene finds new application as nontoxic, anti-static hair dye.” The announcement spawned headlines like “<a href="http://www.sciencemag.org/news/2018/03/enough-toxic-hair-dyes-we-could-use-graphene-instead">Enough with the toxic hair dyes. We could use graphene instead</a>,” and “<a href="http://en.brinkwire.com/215369/miracle-material-graphene-used-to-create-the-ultimate-hair-dye/">’Miracle material’ graphene used to create the ultimate hair dye</a>.” </p>
<p>From these headlines, you might be forgiven for getting the idea that the safety of graphene-based hair dyes is a done deal. Yet <a href="https://scholar.google.com/citations?user=b8NhWc4AAAAJ&hl=en&oi=ao">having studied the potential health and environmental impacts</a> of engineered nanomaterials for <a href="http://dx.doi.org/10.1038/nnano.2016.270">more years than I care to remember</a>, I find such overly optimistic pronouncements worrying – especially when they’re not backed up by clear evidence.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/211008/original/file-20180319-31602-zpomir.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">As the dye wears off, where do the nanoparticles go?</span>
<span class="attribution"><span class="source">Jiaxing Huang, Northwestern University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Tiny materials, potentially bigger problems</h2>
<p>Engineered nanomaterials like graphene and graphene oxide (the particular form used in the dye experiments) aren’t necessarily harmful. But nanomaterials can behave in unusual ways that depend on particle size, shape, chemistry and application. Because of this, researchers have long been cautious about giving them a clean bill of health without first testing them extensively. And while a <a href="http://dx.doi.org/10.1021/acsnano.7b04120">large body of research to date</a> doesn’t indicate graphene is particularly dangerous, neither does it suggest it’s completely safe.</p>
<p>A quick search of scientific papers over the past few years shows that, since 2004, over 2,000 studies have been published that mention graphene toxicity; nearly 500 were published in 2017 alone.</p>
<p>This growing body of research suggests that if graphene gets into your body or the environment in sufficient quantities, it could cause harm. A 2016 review, for instance, indicated that graphene oxide particles could <a href="http://dx.doi.org/10.1016/j.addr.2016.04.028">result in lung damage at high doses</a> (equivalent to around 0.7 grams of inhaled material). Another review published in 2017 suggested that these <a href="http://dx.doi.org/10.1088/2053-1583/aa5476">materials could affect the biology</a> of some plants and algae, as well as invertebrates and vertebrates toward the lower end of the ecological pyramid. The authors of the 2017 study concluded that research “unequivocally confirms that graphene in any of its numerous forms and derivatives must be approached as a potentially hazardous material.” </p>
<p>These studies need to be approached with care, as the precise risks of graphene exposure will depend on how the material is used, how exposure occurs and how much of it is encountered. Yet there’s sufficient evidence to suggest that this substance should be used with caution – especially where there’s a high chance of exposure or that it could be released into the environment.</p>
<p>Unfortunately, graphene-based hair dyes tick both of these boxes. Used in this way, the substance is potentially inhalable (especially with spray-on products) and ingestible through careless use. It’s also almost guaranteed that excess graphene-containing dye will wash down the drain and into the environment. </p>
<p>Here, due diligence is needed to ensure that the material is acceptably safe. This is something that goes beyond the seeming authority of a press release headline. In fact, such misleading headlines could end up being counterproductive, as they undermine efforts to demonstrate trustworthiness with consumers and investors.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=317&fit=crop&dpr=1 600w, https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=317&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=317&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=398&fit=crop&dpr=1 754w, https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=398&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/211020/original/file-20180319-31627-1nv890z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=398&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Simulation of a graphene oxide framework, pictured in black, to remove contaminants from water.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/oakridgelab/14006201292">Adrien Nicolaï/RPI</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Undermining other efforts?</h2>
<p>I was alerted to just how counterproductive such headlines can be by my colleague Tim Harper, founder of <a href="http://g2o.co/">G2O Water Technologies</a> – a company that uses graphene oxide-coated membranes to treat wastewater. Like many companies in this area, G2O has been working to use graphene responsibly by minimizing the amount of graphene that ends up released to the environment.</p>
<p>Yet as Tim pointed out to me, if people are led to believe “that bunging a few grams of graphene down the drain every time you dye your hair is OK, this invalidates all the work we are doing making sure the few nanograms of graphene on our membranes stay put.” Many companies that use nanomaterials are trying to do the right thing, but it’s hard to justify the time and expense of being responsible when someone else’s more cavalier actions undercut your efforts.</p>
<p>Here, naïve claims of safety and gung-ho approaches to promoting graphene-containing products could very easily threaten the responsible development and use of this material. And if companies pull back from acting responsibly, there’s a danger that consumers, investors and even regulators, will lose trust in their ability to ensure the safety of products of all kinds. </p>
<p>If this happens, consumers will be the ultimate losers. Used responsibly, graphene could lead to more sustainable and environmentally benign products. Yet having watched the public backlash against technologies like genetic engineering over the past couple of decades, I’m acutely aware that failing to earn the trust of stakeholders and consumers can stymie technologies, regardless of how safe and beneficial they are.</p>
<h2>Overpromising results and overlooking risk</h2>
<p>This is where researchers and their institutions need to move beyond an “<a href="https://doi.org/10.1038/nnano.2008.14">economy of promises</a>” that spurs on hyperbole and discourages caution, and think more critically about how their statements may ultimately undermine responsible and beneficial development of a technology. They may even want to consider using guidelines, such as the <a href="http://societyinside.com/sites/default/files/Principles%20for%20Responsible%20Innovation%20Short%20February%202018_0.pdf">Principles for Responsible Innovation</a> developed by the organization <a href="http://societyinside.com/">Society Inside</a>, for instance, to guide what they do and say.</p>
<p>To their credit, the authors of the dye study did give a passing mention to research on graphene safety, mostly focusing on an assumed level of safety compared to current dye products. Yet even this perfunctory level of caution failed to make it into the <a href="https://www.eurekalert.org/pub_releases/2018-03/nu-gfn031218.php">press release</a>, which touted a “new hair dye that is nontoxic, nondamaging and lasts through many washes without fading.”</p>
<p>It may turn out that graphene-based hair dyes can be developed safely. To be fair, the reported application isn’t even close to commercial R&D yet, never mind the salon shelf. And certainly, there’s a case to be made for substituting some of the <a href="https://www.nytimes.com/2018/03/16/science/hair-dye-graphene.html">harsh chemicals currently used in some products</a> with more benign ones. But this won’t happen while researchers and their institutions gloss over legitimate concerns and cautions with blind optimism. </p>
<p>Rather, by taking more care in how nanomaterial research is framed and promoted, researchers and their academic institutions could do a lot to ensure future nano-enabled consumer products are safe, beneficial and, above all, responsible.</p><img src="https://counter.theconversation.com/content/93523/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Maynard receives support from the National Science Foundation as part of the Nanotechnology-Enabled Water Treatment (NEWT) Engineering Research Center. </span></em></p>Less-toxic hair dye would be a great invention. But discounting the risks that come with nanoparticles could undermine other efforts to protect human health and environmental from their effects.Andrew Maynard, Director, Risk Innovation Lab, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/863782017-10-26T21:22:44Z2017-10-26T21:22:44ZHow quantum materials may soon make Star Trek technology reality<figure><img src="https://images.theconversation.com/files/192105/original/file-20171026-13298-9jyeex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Strange new materials that propel the fictional Star Trek universe are being developed by scientists in reality today. Above, the USS Discovery accelerates to warp speed in an artist's rendition for the TV series Star Trek Discovery.
</span> <span class="attribution"><span class="source">(Handout)</span></span></figcaption></figure><p>If you think technologies from Star Trek seem far-fetched, think again. Many of the <a href="https://tricorder.xprize.org/">devices</a> from the acclaimed television series are slowly becoming a <a href="https://www.theguardian.com/technology/gallery/2009/may/15/star-trek-technology">reality</a>. While we may not be <a href="http://www.bbc.com/news/science-environment-40594387">teleporting</a> people from starships to a planet’s surface anytime soon, we are getting closer to developing other tools essential for future space travel endeavours.</p>
<p>I am a lifelong Star Trek fan, but I am also a researcher that specializes in creating new magnetic materials. The field of <a href="https://www.physics.utoronto.ca/research/condensed-matter-physics">condensed-matter physics</a> encompasses all new solid and liquid phases of matter, and its study has led to nearly every technological advance of the last century, from computers to cellphones to solar cells.</p>
<p>My approach to looking for new phenomena in materials comes from a chemistry perspective: How can we create materials that have new properties that can change our world, and eventually be used to explore “strange, new worlds”? I believe an understanding of so-called “quantum materials” in particular is essential to make science-fiction science fact. </p>
<h2>Quantum materials</h2>
<p>What makes a substance a quantum material? Quantum materials have unusual and fantastic properties that arise from enormous numbers of particles acting in a concerted way.</p>
<p>Think of a conductor directing a symphony: without some order brought to the music, all you have is noise. The more musicians you have performing out of step, the more noise you will have.</p>
<p>A quantum material has all of the constituent musicians — in this case, the electrons or atoms in a material, which amounts to billions upon billions of particles — acting in a certain way according to quantum rules, or the “sheet music,” if you will.</p>
<p>Instead of noise from random electronic and atomic motions, with a conductor you get music — or in the case of new materials, a new property that emerges. The use of these new properties for devices is what is driving the technological revolutions that we are seeing today.</p>
<h2>Magnetic fields and shields</h2>
<p>So, how can these new materials be used in the spacecraft of tomorrow? One example might be the force-shields that protect ships in Star Trek. High magnetic fields could be used to protect bodies from incoming projectiles, especially if the projectiles have an electric charge.</p>
<p>How do you create large magnetic fields? One way is to use a superconducting magnet. Superconductors have electrons that conduct electricity with no resistance to flow. One of the consequences of this is that large magnetic fields can be generated — the current supported by a superconductor that generates the magnetic field can be huge without destroying the superconductivity itself.</p>
<p>These superconductors are used every day to create large magnetic fields in places such as hospitals for MRI (magnetic resonance imaging) devices to see inside the body.</p>
<p>Advanced superconductors might have new applications as magnetic shields for spacecraft. Imagine your spaceship coated in a superconductor that can generate a large magnetic field with a flick of a switch to get the current flowing, creating a magnetic force shield. </p>
<p>This is exactly what scientists at the European Organization for Nuclear Research, <a href="http://home.cern/about/updates/2015/08/superconducting-shield-astronauts">CERN, are investigating</a>: a new <a href="http://www.popularmechanics.com/space/moon-mars/a16757/cern-spaceship-shields/">magnetic shield for spacecraft</a> — superconducting magnesium diboride, or MgB₂.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/y-0z6_yVSAw?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Physicist and science writer Ian O'Neill discusses CERN’s plan to create a superconducting cosmic radiation shield for astronauts.</span></figcaption>
</figure>
<h2>Superconductors on spaceships</h2>
<p>A spaceship coated in superconducting magnets would generate a “magnetosphere” around the craft which could be used to deflect harmful projectiles. While we don’t have to worry about <a href="http://www.startrek.com/database_article/klingons">Klingon</a> torpedoes just yet, we do have to worry about harmful cosmic rays in outer space for future space travel.</p>
<p><a href="https://home.cern/about/physics/cosmic-rays-particles-outer-space">Cosmic rays</a>) are typically charged particles that can interfere with the electronics of a spacecraft, and more importantly, give astronauts a lethal dose of radiation during long space flights.</p>
<p>Protecting future spacecraft from these rays is crucially important for the future of any space program, including trips to Mars in the next few decades. And who knows, with the superconducting magnet shields you might be able to escape a <a href="http://www.startrek.com/database_article/romulans">Romulan</a> attack on the way.</p>
<h2>Technical hurdles</h2>
<p>There is a catch, however. Superconductors do not work at high temperatures and there is no room-temperature superconductor. Above a certain temperature called the “critical temperature,” the superconductor becomes “normal” and the electrons experience a resistance to flow again. For magnesium diboride, this occurs at a very cold temperature — around -248°C. This is actually fine for interstellar space where the background temperature is a much colder -270°C or so but it is not conducive to spacecraft visiting other warmer planets.</p>
<p>Scientists like me are searching for “room temperature” superconductors that would enable these shields to work at much higher temperatures. This would also enable new advances to society such as cheaper health care, for example, since one wouldn’t need low temperatures for MRI instruments to work.</p>
<p>However, high temperature superconductivity has been a mystery for decades, and progress is in slow increments. As someone who works on the border between physics and chemistry, I believe that the answer will be found in the discovery of new materials. Historically, this is where progress has been made to raise the critical temperature to one above the liquid nitrogen boiling point of -196°C.</p>
<p>These superconductors would be great to use as magnetic shield devices if you were exploring many areas of the galaxy. But they wouldn’t work on warmer planets such as Mars without significant amounts of cryogens to keep the magnets cold.</p>
<h2>Quantum computers and societal revolution</h2>
<p>Superconducting technology would also have a variety of other uses aboard starships. <a href="https://uwaterloo.ca/institute-for-quantum-computing/quantum-computing-101">Quantum computers</a> can perform operations orders of magnitude faster than conventional computers, and would undoubtedly be used on a modern starship. Need to send an encrypted message to Starfleet? If the Klingons have a quantum computer, they might be able to intercept and hack your message, so you had better make sure that you understand the technology.</p>
<p>And superconducting electrical systems would naturally be used for the most efficient devices, from starship engines down to tricorders used in away missions. The emergence of room temperature superconductors would spark a transformation of our society that would rival the silicon age of modern electronics. Their discovery is an essential hurdle to cross for the next part of our evolution as a species to a new technological age.</p>
<p>It would be highly logical to continue our search for a room temperature superconductor. If only we could make it so. Quantum materials offer strange new worlds of discovery and perhaps most exciting are the technologies we haven’t discovered yet — that will exploit quantum effects on scale that humans can easily see.</p><img src="https://counter.theconversation.com/content/86378/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christopher Wiebe receives funding from the Natural Science and Engineering Research Council of Canada (NSERC), the Canadian Foundation for Innovation (CFI), the Canada Research Chairs Program (CRC), and the Canadian Institute for Advanced Research (CIFAR).</span></em></p>Advanced materials that seem like they come from Star Trek are becoming reality today.Christopher Wiebe, Professor and Canada Research Chair in Quantum Materials Discovery, University of WinnipegLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/858692017-10-18T17:25:27Z2017-10-18T17:25:27ZFlowers’ secret signal to bees and other amazing nanotechnologies hidden in plants<figure><img src="https://images.theconversation.com/files/190682/original/file-20171017-30422-7wqfti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Flowers have a secret signal that’s specially tailored <a href="https://www.ncbi.nlm.nih.gov/pubmed/19119235">for bees</a> so they know where to collect nectar. And new research has just given us a greater insight into how this signal works. Nanoscale patterns on the petals reflect light in a way that effectively creates a “blue halo” around the flower that helps attract the bees and encourages pollination.</p>
<p>This fascinating phenomenon shouldn’t come as too much of a surprise to scientists. Plants are actually full of this kind of “nanotechnology”, that enables them to do all kinds of amazing things, from cleaning themselves to generating energy. And, what’s more, by studying these systems we might be able to put them to use in our own technologies.</p>
<p>Most flowers appear colourful because they contain light-absorbing pigments that reflect only certain wavelengths of light. But some flowers also use iridescence, a different type of colour produced when light reflects from microscopically spaced structures or surfaces.</p>
<p>The shifting rainbow colours you can see on a CD are an example of iridescence. It’s caused by <a href="http://www.yalescientific.org/2013/05/qa-what-causes-iridescence/">interactions between light waves</a> bouncing off the closely spaced microscopic indentations in its surface, which means some colours become more intense at the expense of others. As your viewing angle shifts, the amplified colours change to give the shimmering, morphing colour effect that you see.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/190685/original/file-20171017-30410-j3jncf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Bees can see a blue halo around the purple region.</span>
<span class="attribution"><span class="source">Edwige Moyroud</span></span>
</figcaption>
</figure>
<p>Many flowers use grooves between one and two thousandths of a millimetre apart in the wax coating on their surface to produce iridescence in a similar way. But researchers investigating the way that some flowers use iridescence to attract bees to pollinate have <a href="http://nature.com/articles/doi:10.1038/nature24285">noticed something odd</a>. The spacing and alignment of the grooves weren’t quite as perfect as expected. And they weren’t quite perfect in very similar ways in all of the types of flowers that they looked at.</p>
<p>These imperfections meant that instead of giving a rainbow as a CD does, the patterns worked much better for blue and ultra-violet light than other colours, creating what the researchers called a “blue halo”. There was good reason to suspect that this wasn’t a coincidence.</p>
<p>The <a href="http://www.beeculture.com/bees-see-matters/">colour perception of bees</a> is shifted towards the blue end of the spectrum compared to ours. The question was whether the flaws in the wax patterns were “designed” to generate the intense blues, violets and ultra-violets that bees see most strongly. Humans can occasionally see these patterns but they are usually invisible to us against red or yellow pigmented backgrounds that look much darker to bees.</p>
<p>The researchers tested this by training bees to associate sugar with two types of artificial flower. One had petals made using perfectly aligned gratings that gave normal iridescence. The other had flawed arrangements replicating the blue halos from different real flowers.</p>
<p>They found that although the bees learned to associate the iridescent fake flowers with sugar, they learnt better and quicker with the blue halos. Fascinatingly, it seems that many different types of flowering plant may have evolved this structure separately, each using nanostructures that give slightly off-kilter iridescence to strengthen their signals to bees.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/190683/original/file-20171017-30410-wps2h3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Wait a minute! This isn’t a flower.</span>
<span class="attribution"><span class="source">Edwige Moyroud</span></span>
</figcaption>
</figure>
<h2>The lotus effect</h2>
<p>Plants have evolved many ways to use these kind of structures, effectively making them nature’s first nanotechnologists. For example, the waxes that protect the petals and leaves of all plants repel water, a property known as “hydrophobicity”. But in some plants, such as the lotus, this property is enhanced by the shape of the wax coating in a way that effectively makes it self-cleaning.</p>
<p>The wax is arranged in an array of cone-like structures about five thousandths of a millimetre in height. These are in turn coated with fractal patterns of wax at even smaller scales. When water lands on this surface, it can’t stick to it at all and so it forms spherical drops that roll across the leaf picking up dirt along the way until they fall off the edge. This is called “<a href="https://www.teachengineering.org/lessons/view/duk_surfacetensionunit_less4">superhydrophobicity</a>” or the “lotus effect”.</p>
<h2>Smart plants</h2>
<p>Inside plants there is another type of nanostructure. As plants take up water from their roots into their cells, the pressure builds inside the cells until it is like being between 50 metres and 100 metres under the sea. In order to contain these pressures, the cells are surrounded by a wall based on bundles of cellulose chains between five and 50 millionths of a millimetre across called <a href="http://www.plantphysiol.org/content/161/1/465">microfibrils</a>.</p>
<p>The individual chains are not that strong but once they are formed into microfibrils they become as strong as steel. The microfibrils are then embedded in a matrix of other sugars to form a natural “smart polymer”, a special substance that can alter its properties in order to make the plant to grow.</p>
<p>Humans have always used cellulose as a natural polymer, for example in paper or cotton, but scientists are now developing ways to release individual microfibrils to create new technologies. Because of its strength and lightness, this “nanocellulose” could have a huge range of applications. These include <a href="https://www.acs.org/content/acs/en/pressroom/newsreleases/2011/march/green-cars-could-be-made-from-pineapples-and-bananas.html">lighter car parts</a>, <a href="http://bluegoosebiorefineries.com/food-additive/">low calorie food additives</a>, <a href="https://www.sciencedirect.com/science/article/pii/S0958166916000045#bib1295">scaffolds for tissue engineering</a>, and perhaps even <a href="http://pubs.rsc.org/en/content/articlehtml/2016/nr/c6nr03054h">electronic devices that could be as thin as a sheet of paper</a>.</p>
<p>Perhaps the most astonishing plant nanostructures are the light-harvesting systems that capture light energy for photosynthesis and transfer it to the sites where it can be used. Plants are able to move this energy with an incredible 90% efficiency.</p>
<p>We now have evidence that this is because the exact arrangement of the components of the light-harvesting systems allow them to use quantum physics to test many different ways to move the energy simultaneously and <a href="https://www.scientificamerican.com/article/when-it-comes-to-photosynthesis-plants-perform-quantum-computation/">find the most effective</a>. This adds weight to the idea that quantum technology could help provide <a href="http://spie.org/newsroom/6386-quantum-techniques-to-enhance-solar-cell-efficiency?SSO=1">more efficient solar cells</a>. So when it comes to developing new nanotechnology, it’s worth remembering that plants may have got there first.</p><img src="https://counter.theconversation.com/content/85869/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Stuart Thompson has received funding from MAFF and the Nuffield Foundation. He consults to the University of Copenhagen. </span></em></p>New research shows bees see a blue halo around flowers thanks to nanostructures on its petals.Stuart Thompson, Senior Lecturer in Plant Biochemistry, University of WestminsterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/747282017-03-22T18:33:37Z2017-03-22T18:33:37Z3-D printing turns nanomachines into life-size workers<figure><img src="https://images.theconversation.com/files/162085/original/image-20170322-12437-jb8bq0.jpg?ixlib=rb-1.1.0&rect=125%2C107%2C3628%2C2005&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Molecular machines are ready to join forces and take on real-world work.</span> <span class="attribution"><span class="source">Chenfeng Ke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Nanomachines are tiny molecules – more than 10,000 lined up side by side would be narrower than the diameter of a human hair – that can move when they receive an external stimulus. They can already <a href="http://www.pnas.org/content/102/29/10029">deliver medication</a> within a body and serve as <a href="http://www.nature.com/nature/journal/v445/n7126/full/nature05462.html">computer memories</a> at the microscopic level. But as machines go, they haven’t been able to do much physical work – until now. </p>
<p><a href="http://www.keresearchgroup.com">My lab</a> has used nano-sized building blocks to <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201612440/full">design a smart material</a> that can perform work at a macroscopic scale, visible to the eye. A 3-D-printed lattice cube made out of polymer can lift 15 times its own weight – the equivalent of a human being lifting a car.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/Au9ruZ6Kfh0?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Our polymer is able to lift an aluminum plate when chemical energy is added in the form of a solvent.</span></figcaption>
</figure>
<h2>Nobel-winning roots are rotaxanes</h2>
<p>The design of our new material is based on <a href="https://www.nobelprize.org/nobel_prizes/chemistry/laureates/2016/">Nobel Prize-winning research</a> that turned mechanically interlocked molecules into work-performing machines at nanoscale – things like <a href="http://doi.org/10.1126/science.1094791">molecular elevators</a> and <a href="http://doi.org/10.1038/nature10587">nanocars</a>.</p>
<p>Rotaxanes are one of the most widely investigated of these molecules. These dumbbell-shaped molecules are capable of converting input energy – in the forms of light, heat or altered pH – into molecular movements. That’s how these kinds of molecular structures got the nickname “<a href="https://www.nobelprize.org/nobel_prizes/chemistry/laureates/2016/popular-chemistryprize2016.pdf">nanomachines</a>.”</p>
<p>For example, in a molecule called [2]rotaxane, composed of one ring on an axle, the ring can move along the axle to perform shuttling motions. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=196&fit=crop&dpr=1 600w, https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=196&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=196&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=246&fit=crop&dpr=1 754w, https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=246&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/161663/original/image-20170320-9129-oe7dbi.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=246&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Left, a [2]rotaxane. The ring can shuttle along the axle. Right, representation of billions of [2]rotaxanes in solution. The motions of nano-rings counteract macroscopically.</span>
<span class="attribution"><span class="source">Chenfeng Ke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>So far, harnessing the mechanical work of rotaxanes has been very challenging. When billions of these tiny machines are randomly oriented, the ring motions will cancel each other out, producing no useful work at a macroscale. In order to harness these molecular motions, scientists have to think about controlling their three-dimensional arrangement as well as synchronizing their motions. </p>
<h2>Molecular beads on a string</h2>
<p>Our design is based on a well-investigated family of molecules called polyrotaxanes. These have multiple rings on a molecular axle. In our new material, the ring is a cyclic sugar and the axle is a polymer. </p>
<p>If we provide an external stimulus – like adding water – these rings randomly shuttling back and forth can instead stick to each other and form a tubular array. When that happens, it changes the stiffness of the molecule. It’s like when beads are threaded onto a string; many beads slid together make the string much stronger, like a rod.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=123&fit=crop&dpr=1 600w, https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=123&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=123&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=154&fit=crop&dpr=1 754w, https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=154&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/161664/original/image-20170320-9114-1ugcsh3.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=154&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cartoon presentation of a polyrotaxane. The rings are changed from the shuttling state, left, to the stationary state, right.</span>
<span class="attribution"><span class="source">Chenfeng Ke</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Our approach is to build a polymer system where billions of these molecules become stronger with added water. The strength of the whole architecture is increased and the structure can perform useful work.</p>
<p>In this way, we were able to get around the original problem of the random orientation of many nanomachines together. The addition of water locks them into a stationary state, therefore strengthening the whole 3-D architecture and allowing the united molecules to perform work together. </p>
<h2>3-D printing the material</h2>
<p>Our research is the first to add 3-D printability to mechanically interlocked molecules. It was integrating the 3-D printing technique that allowed us to transform the random shuttling motions of nano-sized rings into smart materials that perform work at macroscopic scale.</p>
<p>Getting the molecules all lined up in the right orientation is a way to amplify their motions. When we add water, the rings of the polyrotaxanes stick together via hydrogen bonds. The tubular arrays then stack together in a more ordered manner.</p>
<p>It’s much easier to get the molecules coordinated while they’re in this configuration as opposed to when the rings are all freely moving along the axle. We were able to successfully print lattice-like 3-D structures with the rings locked into position in this way. Now the molecules aren’t just randomly positioned within the material.</p>
<p>After 3-D-printing out the polymer, we used a photo-curing process – similar to the UV lamp that hardens nail polish at a salon – to cure it. We were left with a material that had good 3-D structural integrity and mechanical stability. Now it was ready to do some work.</p>
<h2>Shape changing back and forth</h2>
<p>The three-dimensional geometry of the polymer is crucial for its shape changing. A hollow structure is easier to deform than a solid one. So we designed a lattice cube structure to maximize its shape-deformation ability and, in turn, its ability to do work as it switched back and forth from one state to the other.</p>
<p>The next important step was being able to control the work our polymer could do.</p>
<p>It turns out the complex 3-D architecture of these structures can be reversibly deformed and reformed. We were able to use a solvent to switch the threaded ring structure between random shuttling and stationary states at the molecular level. Exchanging the solvent let us easily repeat this shape-changing and recovery behavior many times.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5h6CzJb9BqM?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Squirting in solvent adds chemical energy to our polymer. As the solvent evaporated over time, the polyrotaxane returned to its original form.</span></figcaption>
</figure>
<p>This is how we converted chemical energy into mechanical work.</p>
<p>Just like moving beads to strengthen or weaken a string, this shape-changing is critical because it allows the amplification of molecular motion into macroscopic motion.</p>
<p>A 3-D printed lattice cube made of this smart material lifted a small coin 1.6 millimeters. The numbers may sound small for our day-to-day world, but this is a big step forward in the effort to get nanomachines doing macro work.</p>
<p>We hope <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201612440/full">this advance</a> will enable scientists to further develop smart materials and devices. For example, by adding contraction and twisting to the rising motion, molecular machines could be used as soft robots performing complicated tasks similar to what a human hand can do.</p><img src="https://counter.theconversation.com/content/74728/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chenfeng Ke does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Research on molecular machines won last year’s Nobel Prize in chemistry. Now scientists have figured out a way to get these tiny molecules to join forces and collaborate on real work on a macro scale.Chenfeng Ke, Assistant Professor of Chemistry, Dartmouth CollegeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/711222017-02-15T15:01:29Z2017-02-15T15:01:29ZFive ways nanoscience is making science fiction into fact<figure><img src="https://images.theconversation.com/files/156965/original/image-20170215-27421-kxpydc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/nanotechnology-science-medicine-126734096?src=uxpKWm6hcwfLGg2BCHVkJg-1-44">www.shutterstock.com</a></span></figcaption></figure><p>Russian author Boris Zhitkov wrote the 1931 short story <a href="https://ru.wikisource.org/wiki/%D0%9C%D0%B8%D0%BA%D1%80%D0%BE%D1%80%D1%83%D0%BA%D0%B8_(%D0%96%D0%B8%D1%82%D0%BA%D0%BE%D0%B2)">Microhands</a>, in which the narrator creates miniature hands to carry out intricate surgeries. And while that was nearly 100 years ago, the tale illustrates the real fundamentals of the <a href="http://tmi.utexas.edu/resources/what-is-nanoscience/">nanoscience</a> researchers are working on today. </p>
<p>Nanoscience is the study of molecules that are one billionth of a metre in size. To put this into perspective, a human hair is between 50,000 and 100,000 nanometres thick. At this tiny size, materials possess properties that lie somewhere between a lump of metal and that of a single atom. This unique environment means they can become very reactive and be used as catalysts.</p>
<p>The ideas behind nanoscience are often easier to understand when considered simply in terms of how a single material’s properties change. But the field is not limited to just that: we are now moving into the realm of healthcare therapies, and vehicles smaller than a speck of dust. What were once regarded as science fictions are rapidly becoming fact.</p>
<h2>1. Medi-gels</h2>
<p>In video games like Bioware’s Mass Effect, players are able to heal characters’ injuries with the seemingly miraculous <a href="http://masseffect.wikia.com/wiki/Medi-gel">medi-gel</a>. Though it may not give you the unlimited life or epic adventure that a video game can, there is a real-life gel that can similarly stop an arterial bleed in seconds.</p>
<p>“<a href="https://cresilon.com/index.php/vetigel/">Veti-gel</a>” is made of <a href="http://www.newworldencyclopedia.org/entry/Polysaccharide">polysaccharide polymers</a> found in the cell walls of plants which, when applied to wounds, can mimic the structure of the extracellular matrix – the complex web in which cells sit. The gel essentially acts as scaffolding for the matrix to reform, pulling it back together and stopping bleeding without any pressure. </p>
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<h2>2. Healing molecules</h2>
<p>Indeed, wound healing is a key feature of many an action-packed science fiction plot line. Handheld tools have <a href="https://theconversation.com/our-star-trek-style-skin-healing-technology-could-be-the-end-of-chronic-wounds-44608">already been created</a>, similar to Star Trek’s dermal regenerator, to heal injuries.</p>
<p>On the nano-level, a team has developed gel nanoparticles which target a specific enzyme (FL2) which <a href="https://www.ncbi.nlm.nih.gov/pubmed/25756798">slows the migration of skin cells to wounds</a>. They hypothesised that reducing the levels of this enzyme would increase rates of wound healing. </p>
<p>However, delivering the molecules of Silencing RNA (SiRNA) needed to slow the enzyme down would normally be difficult, as unprotected chains of RNA quickly degrade within the body. So these SiRNA molecules were placed inside nano-sized gel shells to aid uptake and their transport into cells. Wounds treated this way healed twice as fast as those which were not, while maintaining normal tissue regeneration. </p>
<h2>3. Self-repairing tech</h2>
<p>The film Terminator 2 features an evil robot that <a href="https://www.youtube.com/watch?v=mTUGXB4i2wI">can repair itself, “healing” in a few seconds</a>. Thankfully, the reality is nowhere near as scary – though we are close to having technology that fixes itself.</p>
<p>Chemists have devised <a href="http://iopscience.iop.org/article/10.1088/0964-1726/23/11/115002">self-healing carbon fibre polymers</a> that break when stress is applied, allowing an epoxy resin to seep from the material and mix with a catalyst. When the resin and catalyst come into contact, a strong plastic with a healing efficiency of up to 108% is formed. The technology is comparable to the healing of a bruise, but instead of bursting a couple of blood vessels, the resin is released. </p>
<p>At a basic level, this may mean that we need never worry about a cracked phone screen again. But it could also <a href="http://www.bbc.co.uk/news/technology-33047859">repair the tiny cracks</a> that develop on planes while they are in flight, or even <a href="http://www.rawstory.com/2015/08/nasa-creates-self-healing-terminator-material-that-can-seal-up-a-bullet-hole-in-2-seconds/">seal bullet holes</a>.</p>
<h2>4. Racing micro-cars</h2>
<p>In 1966, cinema-goers were wowed as the crew of a submarine was shrunk down to microscopic size, and injected into the body of a scientist in the film Fantastic Voyage. Though we are certainly not anywhere near injecting tiny humans into other humans, scientists have created molecular-size vehicles that can be driven in particular directions.</p>
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<p>In 2011, <a href="https://theconversation.com/from-muscles-to-motors-2016-chemistry-nobel-goes-to-creators-of-the-worlds-tiniest-machines-66596">scientist Ben Feringa</a> constructed a <a href="http://www.nature.com/nature/journal/v479/n7372/full/nature10587.html">four-wheeled nanocar</a>, comprised of four molecular motors on a carbon chain chassis. With wheels only <a href="http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2016/popular-chemistryprize2016.pdf">60 atoms in size</a> and a width more than 666,666,666 times smaller than a Formula 1 car, it might be hard to <a href="http://www.dailymotion.com/video/x3cr6jv_move-in-atomline_tech">imagine driving</a>, let alone racing, these tiny vehicles. But this year the <a href="http://www.cemes.fr/Molecule-car-Race?lang=en">first two-day nanocar race</a> will take place. Teams will compete on a course made entirely of gold, painstakingly constructed atom by atom. Extra atoms will be placed on the surface to act as obstacles which competitors will have to navigate around.</p>
<h2>5. Fantasy foods</h2>
<p>Roald Dahl’s Charlie and the Chocolate Factory has made millions of mouths water over the years, thanks to the author’s vivid descriptions of quirky tastes and inventive sweets.</p>
<p>In reality, there aren’t chewing gums that taste like a three-course dinner – <a href="http://www.dailymail.co.uk/sciencetech/article-1317950/Willy-Wonka-3-course-meal-stick-chewing-gum-possibility.html">just yet</a> – or fizzy pop that makes you fly. But food manufacturers have been working on ways to change tastes and textures using molecular technology.</p>
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<p>Nanotech has been <a href="https://www.theguardian.com/what-is-nano/nanotechnology-small-food-for-thought">used in food for many years</a> – emulsifiers in mayonnaise, for example – but now scientists are looking at how it can be used to enhance nutrition and the aesthetics of common foods. </p>
<p>Australian bakery Tip-Top are using nanocapsules to <a href="http://www.azonano.com/article.aspx?ArticleID=3226#4">add omega-3 oil to bread</a>. The capsules only open in the correct environment – the stomach – and so can bring the benefits of Omega-3 without the unpleasant taste. Likewise, companies such as Nestle and Unilever are also researching nanocapsules to <a href="http://www.forbes.com/2005/08/09/nanotechnology-kraft-hershey-cz_jw_0810soapbox_inl.html">improve the texture of their food</a>.</p>
<p>Though nano-techology can’t do <a href="https://www.theguardian.com/what-is-nano/nanotechnology-small-food-for-thought">everything that science fiction</a> has promised just yet, it is changing the world as we know it. And the smaller we continue to go, the bigger the potential will be.</p><img src="https://counter.theconversation.com/content/71122/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Josh Davies-Jones does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Once the subject of fantastical stories, nanoscience is now changing the world as we know it.Josh Davies-Jones, PhD researcher, Cardiff UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/605972016-10-21T01:45:50Z2016-10-21T01:45:50ZThe next frontier in medical sensing: Threads coated in nanomaterials<figure><img src="https://images.theconversation.com/files/142056/original/image-20161017-12463-1t71g90.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A hydro-responsive thread can be used with sensors to monitor body functions.</span> <span class="attribution"><span class="source">Alonso Nichols, Tufts University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Doctors have various ways to assess your health. For example, they <a href="http://dx.doi.org/10.1016/j.amjmed.2015.11.039">measure your heart rate and blood pressure</a> to indirectly assess your heart function, or straightforwardly <a href="http://dx.doi.org/10.1111/j.1537-2995.2012.03784.x">test a blood sample for iron content</a> to diagnose anemia. But there are plenty of situations in which that sort of monitoring just isn’t possible. </p>
<p>To test the <a href="https://www.researchgate.net/profile/Viktor_Lindgren/publication/268787806_Deep_infection_after_total_hip_replacement_a_method_for_national_incidence_surveillance/links/5488b0540cf2ef344790a330.pdf">health of muscle and bone in contact with a hip replacement</a>, for example, requires a complicated – and expensive – procedure. And if problems are found, it’s often too late to truly fix them. The same is true when dealing with deep wounds or internal incisions from surgery.</p>
<p>In <a href="http://nanolab.ece.tufts.edu/">my engineering lab at Tufts University</a>, we asked ourselves whether we could make sensors that could be seamlessly embedded in body tissue or organs – and yet could communicate to monitors outside the body in real time. The first concern, of course, would be to make sure that the materials wouldn’t cause infection or an immune response from the body. The sensors would also need to match the mechanical properties of the body part they would be embedded in: soft for organs and stretchable for muscle. And, ideally, they would be relatively inexpensive to make in large quantities.</p>
<p>Our search for materials we might use led us to a surprising candidate – threads, just like what our clothes are made of. Thread has many advantages. It is abundant, easy to make and very inexpensive. Threads can be made flexible and stretchable – and even from materials that aren’t rejected by the body. In addition, doctors are very comfortable working with threads: They routinely use sutures to stitch up open wounds. What if we could <a href="http://dx.doi.org/10.1038/micronano.2016.39">embed sensor functions into threads</a>?</p>
<h2>Finding the right sensor</h2>
<p>Today’s medical sensors are typically rigid and flat – which limits them to monitoring surfaces such as the scalp or skin. But most organs and tissues are three-dimensional heterogeneous multilayered biological structures. To monitor them, we need something much more like a thread.</p>
<p>Nanomaterials can be organic or inorganic, inert or bioactive, and can be designed with physical and chemical properties that are useful for medical sensing. For example, carbon nanotubes are amazingly versatile – their <a href="http://dx.doi.org/10.1002/adfm.201302344">electrical conductivity can be customized</a>, which has led to them being the basis of the next generation of sensors and electronic transistors. They can even <a href="http://dx.doi.org/10.1021/ja4000917">detect single molecules</a> of DNA and proteins. The <a href="http://dx.doi.org/10.1039/C2EE24203F">organic nanomaterial polyaniline</a> has a similarly broad range of applications, notably its conductivity depends on the strength of the acid or base it is in contact with.</p>
<h2>Making the materials</h2>
<p>To make sensing threads, we start with cotton and other conventional threads, dip them in liquids containing different nanomaterials, and rapidly dry them. Depending on the properties of the nanomaterial we use, these can monitor mechanical or chemical activity. </p>
<p>For example, coating stretchable rubber fiber with carbon nanotubes and silicone can make threads that can sense and measure physical strain. As they stretch, the threads’ electrical properties change in ways we can monitor externally. This can be used to monitor wound healing or muscle strain experienced due to artificial implants. After an implant, abnormal strain could be a sign of slow healing, or even improper placement of the device. Threads monitoring strain levels can send a message to both patient and doctor so that treatment can be modified appropriately.</p>
<p>Monitoring the electricity flow between one cotton thread coated with carbon nanotubes and polyaniline nanofibers, and another coated with silver and silver chloride, allows us to measure acidity, which can be a sign of infection.</p>
<p>To help people who need to monitor their blood sugar levels, we can coat a thread with <a href="http://dx.doi.org/10.1016/j.bios.2012.06.045">glucose oxidase</a>, which reacts with glucose to generate an electrical signal indicating how much sugar is in the patient’s blood. Similarly, coating conductive threads with other nanomaterials sensitive to specific elements or chemicals can help doctors measure potassium and sodium levels or other metabolic markers in your blood.</p>
<h2>Multiple uses</h2>
<p>Beyond sensing abilities, many thread materials, such as cotton, have another useful property: wicking. They can move liquid along their length via capillary action without needing a pump, the way <a href="http://dx.doi.org/10.1007/BF02896314">melted wax flows up a candlewick</a> to feed the flame.</p>
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<span class="caption">Liquid flowing in threads sutured into skin.</span>
<span class="attribution"><span class="source">Nano Lab, Tufts University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>We used cotton threads to transport <a href="http://dx.doi.org/10.1152/physrev.00037.2011">interstitial fluid</a>, which fills in the gaps between cells, from the places it normally exists toward sensing threads located elsewhere. The sensing threads send their electronic signals to an external device housed in a flexible patch, along with a button battery and a small antenna. There, the signals are amplified, digitized and transmitted wirelessly to a smartphone or any Wi-Fi connected device.</p>
<p>These transport-sensing measuring-transmission systems are so small that they can be powered with a tiny battery sitting on top of the skin or could <a href="http://dx.doi.org/10.1016/j.cej.2014.11.011">get energy from glucose</a> in the patient’s blood. That could allow doctors to keep a continuous eye on patients’ health remotely and unobtrusively. </p>
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<span class="caption">Smart threads can monitor wounds using a suite of physical and chemical sensors made using threads and passing information to a skin-surface transmitter.</span>
<span class="attribution"><a class="source" href="https://now.tufts.edu/news-releases/researchers-invent-smart-thread-collects-diagnostic-data-when-sutured-tissue">Nano Lab, Tufts University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>This type of integrated, wireless monitoring has several advantages over current systems. First, the patient can move around freely, rather than being confined to a hospital bed. In addition, real-time data-gathering provides much more accurate information than periodic testing at a hospital or doctor’s office. And it reduces the cost of health care by moving treatment, monitoring and diagnosis out of the hospital.</p>
<p>So far our testing of nano-infused threads has been in sterile lab environments in rodents. The next step is to perform more tests in animals, particularly to monitor how well the threads do in living tissue over long periods of time. Then we’d move toward testing in humans. </p>
<p>Now that we’ve begun exploring the possibilities of threads, potential uses seem to be everywhere. Diabetic patients can have trouble with <a href="http://dx.doi.org/10.1242/dmm.012237">wounds resisting healing</a>, which can lead to infection, and even amputation. A few choice stitches using sensing threads could let doctors detect these problems at extremely early stages – much sooner than we can today – and take action to prevent them from worsening. Sensing threads can even be woven into bandages, wound dressings or hospital bed sheets to monitor patients’ progress, and raise alarms before problems get out of control.</p><img src="https://counter.theconversation.com/content/60597/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sameer Sonkusale currently receives funding from National Science Foundation and Department of Defense.</span></em></p>Flexible, easy to make, inexpensive, stretchable and simple to coat with nanomaterials, threads are also very commonly used by doctors already.Sameer Sonkusale, Professor of Electrical and Computer Engineering, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/605412016-06-08T01:31:20Z2016-06-08T01:31:20ZNo big deal: there is little to fear from nanoparticles in food<figure><img src="https://images.theconversation.com/files/125486/original/image-20160607-31937-1tz9ov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Some companies have used nano-titanium dioxide to make powdered sugar on donuts whiter.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><a href="https://theconversation.com/au/topics/nanomaterials">Nanomaterials</a>, and especially <a href="https://theconversation.com/au/topics/nanoparticles">nanoparticles</a>, have been on some people’s worry list for at least a decade. </p>
<p>The definition of a nanomaterial is rather loose, just specifying that it must have at least one dimension of 100 nanometres or less. This means that the material could be a sheet, fibre, wire or a particle. </p>
<p>For nanoparticles in particular, all three dimensions are likely to be tiny. This means they will often be about 100 times smaller than the particles in air pollution, which range in size from 10 micrometres (PM10) down to 2.5 micrometres (PM2.5).</p>
<p>The substances that make up the nanoparticles – most often the oxides of zinc, silicon and titanium – and are generally not regarded as toxic. But the particles are so small that their behaviour can be quite different from what we see on a large scale.</p>
<p>We know that nanoparticles in sunscreens and cosmetics can penetrate the skin, and this raises questions about what they can do in the body. Nanosilver is also used as a disinfectant, such as when it is included in clothing items like socks.</p>
<p>In terms of food, nanoparticles can be present at levels of a few percent, often mixed with larger particles. Some foods have silicon dioxide (silica) as an anti-clumping agent to keep mixtures free-flowing, while others have titanium dioxide to confer extra whiteness. </p>
<p>You may recall the news item from March last year about the use of <a href="https://theconversation.com/dunkin-donuts-ditches-titanium-dioxide-but-is-it-actually-harmful-38627">titanium dioxide in the frosting of donuts</a>. The application was withdrawn in the face of consumer resistance. </p>
<p>The use of nanosilver in food is restricted but there may be residues on fruit and vegetables that have been disinfected by washing with suspensions of nanosilver.</p>
<p>While there is no sign that nanomaterials are used in food packaging in Australia or New Zealand, they are being used overseas. Some applications are adding nanoparticles of clay to make packaging more robust, or adding nanosilver as a disinfectant. </p>
<p>Some future developments could involve nanoparticles that act as indicators, by changing colour for instance, if the contents deteriorate in quality over time.</p>
<h2>Small risks</h2>
<p>Keeping an eye on our food is the bi-national government agency Food Standards Australia and New Zealand (<a href="http://www.foodstandards.gov.au/Pages/default.aspx">FSANZ</a>), which has just released two long-awaited reports on the safety of nanoparticles in food, one on <a href="http://www.foodstandards.gov.au/publications/Documents/Safety%20of%20nanotechnology%20in%20food.pdf">additives</a> and one on <a href="http://www.foodstandards.gov.au/publications/Documents/Nanotech%20in%20food%20packaging.pdf">packaging</a>.</p>
<p>The reports were commissioned in 2015 and were written by one of Australia’s leading toxicologists, <a href="https://toxconsult.com.au/our-consultants/dr-roger-drew/">Dr Roger Drew</a>, and his colleague <a href="https://toxconsult.com.au/our-consultants/ms-tarah-hagen/">Tarah Hagen</a>. </p>
<p>Both reports were based on comprehensive surveys of the scientific literature and relevant patents.</p>
<p>The upshot of both reports is that the most common nanoscale materials likely to be present in food or food packaging – silicon dioxide, titanium dioxide and metallic silver – do not pose significant health risks. </p>
<p>In terms of food, many common foods already contain <a href="https://www.researchgate.net/publication/281208209_Naturally_Occurring_Nanoparticles_in_Food">natural nanoparticles</a>, but FSNAZ was specifically interested in “engineered” or manufactured nanoparticles and their effects.</p>
<p>In terms of packaging, studies where nanomaterials are used in packaging have shown that nanomaterials can migrate from the packaging into the food therein.</p>
<p>Ingested nanoparticles can, and do, get into the body in places where bulk materials cannot, but there is no evidence that mere size is responsible for the effects observed in laboratory studies. </p>
<p>Any impact is caused by soluble materials or colloids, such as gels, that are formed by interaction of the nanomaterials with aggressive components, such as food acids or body fluids. </p>
<p>Soluble materials bring the elements – silicon, titanium and silver – into contact with vital systems. The case of silver is especially interesting since silver is not bioactive until the metal is converted to silver ions, which is when it becomes harmful.</p>
<p>However, the authors noted that there have been few studies of the effects of nanoparticles on large populations of people. That said, nanomaterials have been used for many years, and there has been no evidence of harm. </p>
<p>Also, in order to make an accurate risk assessment, you need to look at both hazard (in this case, toxicity) and exposure. So a substance that is highly toxic might still be low risk if exposure is typically very low.</p>
<p>There have been few regulatory studies on nanoparticles in which hazard and exposure have been considered together, so it’s difficult to provide a comprehensive risk assessment.</p>
<h2>What it means for us</h2>
<p>It’s understandable that many people are wary of a new technology that has unknown effects on health.</p>
<p>However, these reports should reassure us that the scientific and empirical evidence to date suggests nanoparticles in food or food packaging pose low risk.</p>
<p>That doesn’t mean there isn’t more work to be done to learn more about nanoparticles and their biological effects. However, given the expense of mounting large-scale studies, and the likelihood that they will also find no significant health effects, the cost may not be justified.</p>
<p>Nonetheless, we should expect FSANZ to follow developments in the science and, most importantly, to learn more about just which nanomaterials are used in food and packaging applications in Australia. It would be good if this were also to lead to improved food labelling standards.</p><img src="https://counter.theconversation.com/content/60541/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Rae does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Two new studies from Food Standards Australia and New Zealand show there’s no evidence that nanoparticles in food present a health risk, but there’s more research to be done.Ian Rae, Honorary Professorial Fellow, School of Chemistry, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/592462016-05-17T10:04:47Z2016-05-17T10:04:47ZNanoparticles in baby formula: should parents be worried?<figure><img src="https://images.theconversation.com/files/122746/original/image-20160516-15906-1ymu3xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">What's in the bottle is good for me, right?</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/21524179@N08/3669555322">nerissa's ring</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>There’s a lot of stuff you’d expect to find in baby formula: proteins, carbs, vitamins, essential minerals. But parents probably wouldn’t anticipate finding extremely small, needle-like particles. Yet this is exactly what a team of scientists here at Arizona State University <a href="http://www.foe.org/projects/food-and-technology/nanotechnology/baby-formula">recently discovered</a>.</p>
<p>The research, commissioned and published by Friends of the Earth (<a href="http://www.foe.org/">FoE</a>) – an environmental advocacy group – analyzed six commonly available off-the-shelf baby formulas (liquid and powder) and found nanometer-scale needle-like particles in three of them. The particles were made of hydroxyapatite – a poorly soluble calcium-rich mineral. Manufacturers use it to regulate acidity in some foods, and it’s also available as a dietary supplement.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=596&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=596&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=596&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=748&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=748&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122339/original/image-20160512-5088-12g9emr.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=748&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Needle-like particles of hydroxyapatite found in infant formula by ASU researchers.</span>
<span class="attribution"><span class="source">Westerhoff and Schoepf/ASU</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Looking at these particles at super-high magnification, it’s hard not to feel a little anxious about feeding them to a baby. They appear sharp and dangerous – not the sort of thing that has any place around infants. And they are “nanoparticles” – a family of ultra-small particles that have been <a href="http://dx.doi.org/10.1038/444267a">raising safety concerns within the scientific community</a> and elsewhere for some years.</p>
<p>For all these reasons, questions like “should infants be ingesting them?” make a lot of sense. However, as is so often the case, the answers are not quite so straightforward.</p>
<h2>What are these tiny needles?</h2>
<p>Calcium is an essential part of a growing infant’s diet, and is a <a href="http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=107.100">legally required component</a> in formula. But not necessarily in the form of hydroxyapatite nanoparticles.</p>
<p>Hydroxyapatite is a tough, durable mineral. It’s naturally made in our bodies as an essential part of bones and teeth – <a href="https://en.wikipedia.org/wiki/Hydroxylapatite">it’s what makes them so strong</a>. So it’s tempting to assume the substance is safe to eat. But just because our bones and teeth are made of the mineral doesn’t automatically make it safe to ingest outright.</p>
<p>The issue here is what the hydroxyapatite in formula might do before it’s digested, dissolved and reconstituted inside babies’ bodies. The size and shape of the particles ingested has a lot to do with how they behave within a living system.</p>
<p>Size and shape can make a difference between <a href="http://www.webmd.com/news/breaking-news/food-additives/20150723/nanoparticles-food-additives">safe and unsafe</a> when it comes to particles in our food. Small particles aren’t necessarily bad. But they can potentially get to parts of our body that larger ones can’t reach. Think through the gut wall, into the bloodstream, and into organs and cells. Ingested nanoscale particles may be able to <a href="http://dx.doi.org/10.1080/02652030701744538">interfere with cells</a> – even beneficial gut microbes – in ways that larger particles don’t.</p>
<p>These possibilities don’t necessarily make nanoparticles harmful. Our bodies are pretty well adapted to handling naturally occurring nanoscale particles – you probably ate some last time you had burnt toast (carbon nanoparticles), or poorly washed vegetables (clay nanoparticles from the soil). And of course, how much of a material we’re exposed to is at least as important as how potentially hazardous it is. </p>
<p>Yet there’s a lot we still don’t know about the safety of intentionally engineered nanoparticles in food. Toxicologists have <a href="http://dx.doi.org/10.1289%2Fehp.7339">started paying close attention to such particles</a>, just in case their tiny size makes them more harmful than otherwise expected.</p>
<p>So where does this leave us with nanoscale hydroxyapatite needles in infant formula?</p>
<h2>What do regulators know about nano-safety?</h2>
<p>Putting particle size to one side for a moment, hydroxyapatite is classified by the US Food and Drug Administration (FDA) as “Generally Regarded As Safe.” That means it considers the material safe for use in food products – at least in a non-nano form. However, <a href="http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/ucm300661.htm">the agency has raised concerns</a> that nanoscale versions of food ingredients may not be as safe as their larger counterparts. </p>
<p>Some manufacturers may be interested in the potential benefits of “nanosizing” – such as increasing the uptake of vitamins and minerals, or altering the physical, textural and sensory properties of foods. But because decreasing particle size may also affect product safety, the FDA indicates that intentionally nanosizing already regulated food ingredients could require regulatory reevaluation.</p>
<p>In other words, even though non-nanoscale hydroxyapatite is “Generally Regarded As Safe,” according to the FDA, the safety of any nanoscale form of the substance would need to be reevaluated before being added to food products.</p>
<p>Despite this size-safety relationship, the FDA confirmed to me that the agency is unaware of <em>any</em> food substance intentionally engineered at the nanoscale that has enough generally available safety data to determine it should be “Generally Regarded As Safe.”</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=597&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=597&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=597&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=751&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=751&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122057/original/image-20160511-18165-nr0qig.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=751&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hydroxyapatite nanoparticles may have different health effects from larger versions of the mineral.</span>
<span class="attribution"><span class="source">Westerhoff and Schoepf/ASU</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Casting further uncertainty on the use of nanoscale hydroxyapatite in food, a 2015 report from the European Scientific Committee on Consumer Safety (SCCS) suggests there <a href="http://ec.europa.eu/health/scientific_committees/consumer_safety/docs/sccs_o_191.pdf">may be some cause for concern</a> when it comes to this particular nanomaterial. </p>
<p>Prompted by the use of nanoscale hydroxyapatite in dental products to strengthen teeth (which they consider “cosmetic products”), the SCCS reviewed published research on the material’s potential to cause harm. Their conclusion?</p>
<blockquote>
<p>The available information indicates that nano-hydroxyapatite in needle-shaped form is of concern in relation to potential toxicity. Therefore, needle-shaped nano-hydroxyapatite should not be used in cosmetic products.</p>
</blockquote>
<p>This recommendation was based on a handful of studies, none of which involved exposing people to the substance. Researchers injected hydroxyapatite needles directly into the bloodstream of rats. Others exposed cells outside the body to the material and observed the effects. In each case, there were tantalizing hints that the small particles interfered in some way with normal biological functions. But the results were insufficient to indicate whether the effects were meaningful in people.</p>
<p>Importantly, these studies didn’t consider what happens when particles like this end up in the digestive system, including the stomach.</p>
<h2>So what happens when a baby eats them?</h2>
<p>The good news is that, according to preliminary studies from ASU researchers, hydroxyapatite needles don’t last long in the digestive system.</p>
<p>This research is still being reviewed for publication. But early indications are that as soon as the needle-like nanoparticles hit the highly acidic fluid in the stomach, they begin to dissolve. So fast in fact, that by the time they leave the stomach – an exceedingly hostile environment – they are no longer the nanoparticles they started out as.</p>
<p>These findings make sense since we know hydroxyapatite dissolves in acids, and small particles typically dissolve faster than larger ones. So maybe nanoscale hydroxyapatite needles in food are safer than they sound.</p>
<p>This doesn’t mean that the nano-needles are completely off the hook, as some of them may get past the stomach intact and reach more vulnerable parts of the gut. But the findings do suggest these ultra-small needle-like particles could be an effective source of dietary calcium – possibly more so than larger or less needle-like particles that may not dissolve as quickly.</p>
<p>Intriguingly, recent research has indicated that calcium phosphate nanoparticles form naturally in our stomachs and go on to be <a href="http://doi.org/10.1038/nnano.2015.19">an important part of our immune system</a>. It’s possible that rapidly dissolving hydroxyapatite nano-needles are actually a boon, providing raw material for these natural and essential nanoparticles.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=374&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=374&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=374&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=470&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=470&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122747/original/image-20160516-15926-1q2xeo4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=470&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The formula’s safe, but begs other questions.</span>
<span class="attribution"><span class="source">Andrew Maynard</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Tempest in a baby bottle</h2>
<p>And yet, even if these needle-like hydroxyapatite nanoparticles in infant formula are ultimately a good thing, the FoE report raises a number of unresolved questions. Did the manufacturers knowingly add the nanoparticles to their products? How are they and the FDA ensuring the products’ safety? Do consumers have a right to know when they’re feeding their babies nanoparticles?</p>
<p>Whether the manufacturers knowingly added these particles to their formula is not clear. At this point, it’s not even clear why they might have been added, as hydroxyapatite does not appear to be a substantial source of calcium in most formula. (Calcium in formula can come from a number of sources, including milk solids, calcium carbonate and calcium chloride.) If the nanoparticles’ inclusion was intentional, though, current FDA guidelines suggest that the regulator wouldn’t consider the material safe by default, and should be subject to further evaluation.</p>
<p>Certainly, from the data presented, these particles – so uniform in size and shape – look like they were intentionally manufactured to be nanoscale and needle-like. It’s possible they were supplied to the various manufacturers without any indication of their “nano-ness.” This doesn’t absolve the manufacturers of responsibility. But it does suggest that greater scrutiny and accountability is needed in the supply chain for food ingredients.</p>
<p>And regardless of the benefits and risks of nanoparticles in infant formula, parents have a right to know what’s in the products they’re feeding their children. In Europe, food ingredients must be <a href="http://ec.europa.eu/food/safety/docs/labelling_legislation_infographic_food_labelling_rules_2014_en.pdf">legally labeled if they are nanoscale</a>. In the U.S., there is no such requirement, leaving American parents to feel somewhat left in the dark by producers, the FDA and policy makers.</p>
<p>Given the state of science on nanoscale hydroxyapatite in foods, this is as much an issue of trust as it is safety. The FoE report may exaggerate the possible risks, and raise concerns where few are justified. Yet it’s hard to avoid the reality that, if manufacturers are adding nanoparticles to what we feed our children, we need to know more about how to ensure their safety and benefits. How else can we enable informed decisions? </p>
<p>Luckily, current research suggests hydroxyapatite nanoparticles in formula are most likely safe, and arguably, even beneficial. But given how high the stakes are, safety here should not, and indeed cannot, be taken for granted.</p><img src="https://counter.theconversation.com/content/59246/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Andrew Maynard receives funding support from the Center for Research on Ingredients Risk (CRIS) at Michigan State University. He is also on the Board of Trustees of the International Life Sciences Association North America. He was an independent reviewer on the Friends of the Earth report on nanoparticles in infant formula</span></em></p>Microscopic needle-like particles don’t seem like something you’d want to feed a baby. Whether safe or not, the way we deal with nanoscale food additives leaves plenty of other questions.Andrew Maynard, Director, Risk Innovation Lab, Arizona State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/552542016-03-22T11:23:55Z2016-03-22T11:23:55ZFive ways nanotechnology is securing your future<figure><img src="https://images.theconversation.com/files/115999/original/image-20160322-32283-1f9sla3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hidden tools are making the world a safer place</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The past 70 years have seen the way we live and work transformed by two tiny inventions. The electronic transistor and the microchip are what make all modern electronics possible, and since their development in the 1940s they’ve been getting smaller. Today, one chip can contain as many as <a href="http://www.extremetech.com/extreme/187612-ibm-cracks-open-a-new-era-of-computing-with-brain-like-chip-4096-cores-1-million-neurons-5-4-billion-transistors">5 billion transistors</a>. If cars had followed the same development pathway, we would now be able to drive them at <a href="http://www.cyrrusanalytics.com/#!The-300000-MPH-Volkswagen/cudg/561206a00cf25fa7fe26bc95">300,000mph</a> and they would cost just £3 each. </p>
<p>But to keep this progress going we need to be able to create circuits on the extremely small, nanometre scale. A nanometre (nm) is one billionth of a metre and so this kind of engineering involves <a href="http://mashable.com/2013/05/01/ibm-atomic-movie/#mI9MdlKo9uq5">manipulating individual atoms</a>. We can do this, for example, by firing a <a href="http://www.sciencedirect.com/science/article/pii/S0169433200003524">beam of electrons</a> at a material, or by vaporising it and depositing the resulting gaseous atoms <a href="http://www.sciencedirect.com/science/article/pii/S1369702114001436">layer by layer</a> onto a base.</p>
<p>The real challenge is using such techniques reliably to manufacture working nanoscale devices. The physical properties of matter, such as its melting point, electrical conductivity and chemical reactivity, become very different at the nanoscale, so shrinking a device can <a href="http://www.nano.gov/nanotech-101/special">affect its performance</a>. If we can master this technology, however, then we have the opportunity to improve not just electronics but all sorts of areas of modern life.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=393&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=393&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=393&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=494&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=494&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115989/original/image-20160322-32309-1gvd1se.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=494&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Medical nanobots.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>1. Doctors inside your body</h2>
<p>Wearable fitness technology means we can monitor our health by strapping gadgets to ourselves. There are even prototype electronic tattoos that can <a href="http://www.wired.com/2013/03/sensor-tattoos/">sense our vital signs</a>. But by scaling down this technology, we could go further by implanting or injecting tiny sensors inside our bodies. This would capture much more detailed information with less hassle to the patient, enabling doctors to personalise their treatment.</p>
<p>The possibilities are endless, ranging from monitoring inflammation and post-surgery recovery to more exotic applications whereby electronic devices actually interfere with our body’s signals for controlling organ function. Although these technologies might sound like a thing of the far future, multi-billion healthcare firms <a href="http://www.cnbc.com/2015/03/11/glaxosmithklines-big-bet-on-electroceuticals.html">such as GlaxoSmithKline</a> are already working on ways to develop so-called “electroceuticals”.</p>
<h2>2. Sensors, sensors, everywhere</h2>
<p>These sensors rely on newly-invented <a href="http://www.azonano.com/article.aspx?ArticleID=4152">nanomaterials and manufacturing techniques</a> to make them smaller, more complex and more energy efficient. For example, sensors with very fine features can now be printed in large quantities on flexible rolls of plastic at low cost. This opens up the possibility of placing sensors at lots of points over <a href="http://www.rh.gatech.edu/news/206881/wireless-smart-skin-sensors-could-provide-remote-monitoring-infrastructure">critical infrastructure</a> to constantly check that everything is running correctly. Bridges, aircraft and even nuclear power plants could benefit.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115992/original/image-20160322-32323-xbcrq5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Worried about your hairline?</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>3. Self-healing structures</h2>
<p>If cracks do appear then nanotechnology could play a further role. Changing the structure of materials at the nanoscale can give them some amazing properties – by giving them a texture <a href="http://edition.cnn.com/2013/01/17/tech/mobile/p2i-liquid-repellent-nano-coating/">that repels water</a>, for example. In the future, nanotechnology coatings or additives will even have the potential to allow materials to “heal” when damaged or worn. For example, dispersing nanoparticles throughout a material means that they can migrate to fill in any cracks that appear. This could produce self-healing materials for everything from <a href="http://phys.org/news/2006-02-nano-world-self-healing-material.html">aircraft cockpits to microelectronics</a>, preventing small fractures from turning into large, more problematic cracks.</p>
<h2>4. Making big data possible</h2>
<p>All these sensors will produce more information than we’ve ever had to deal with before – so we’ll need the technology to process it and <a href="http://www.forbes.com/sites/ciocentral/2012/07/05/best-practices-for-managing-big-data/#275083feef02">spot the patterns</a> that will alert us to problems. The same will be true if we want to use the “<a href="https://theconversation.com/explainer-what-is-big-data-13780">big data</a>” from traffic sensors to help <a href="https://theconversation.com/how-big-data-and-the-sims-are-helping-us-to-build-the-cities-of-the-future-47292">manage congestion</a> and prevent accidents, or <a href="https://theconversation.com/the-promise-and-perils-of-predictive-policing-based-on-big-data-48366">prevent crime</a> by using statistics to more effectively allocate police resources.</p>
<p>Here, nanotechnology is helping to create <a href="https://www.theengineer.co.uk/nanostructured-glass-used-for-high-density-5d-data-storage/">ultra-dense memory</a> that will allow us to store this wealth of data. But it’s also providing the inspiration for ultra-efficient algorithms for processing, encrypting and communicating data without compromising its reliability. Nature has several examples of big-data processes efficiently being performed in real-time by tiny structures, such as the parts of <a href="https://www.technologyreview.com/s/522476/thinking-in-silicon/">the eye and ear</a> that turn external signals into information for the brain. </p>
<p>Computer architectures <a href="http://blogs.scientificamerican.com/observations/brain-inspired-computing-reaches-a-new-milestone/">inspired by the brain</a> could also use energy more efficiently and so would struggle less with excess heat – one of the key problems with shrinking electronic devices further.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/115995/original/image-20160322-32283-1x11t7u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">From nano tech to global warming.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>5. Tackling climate change</h2>
<p>The fight against climate change means we need new ways to generate and use electricity, and nanotechnology is already playing a role. It has helped create <a href="https://theconversation.com/lithium-air-a-battery-breakthrough-explained-50027">batteries that can store more energy</a> for electric cars and has enabled <a href="http://www.nanowerk.com/nanotechnology-news/newsid=37903.php">solar panels to convert more sunlight into electricity</a>. </p>
<p>The common trick in both applications is to <a href="http://www.telegraph.co.uk/news/science/science-news/12174733/Smart-wallpaper-which-absorbs-light-could-help-power-home.html">use nanotexturing</a> or nanomaterials (for example nanowires or carbon nanotubes) that turn a flat surface into a three-dimensional one with a much greater surface area. This means that there is more space for the reactions that enable energy storage or generation to take place, so the devices operate more efficiently</p>
<p>In the future, nanotechnology could also enable objects to harvest energy from their environment. New nano-materials and concepts are currently being developed that show potential for producing <a href="http://www.nanowerk.com/spotlight/spotid=33308.php">energy from movement</a>, light, variations in temperature, glucose and other sources with high conversion efficiency.</p><img src="https://counter.theconversation.com/content/55254/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Themis Prodromakis receives funding from the Lloyds Register Foundation, the EPSRC and the EU Commission. </span></em></p>From tiny robotic doctors repairing your body to the latest climate change-tackling tools, nanotechnology is fighting an invisible battle on our behalf.Themis Prodromakis, Reader in Nanoelectronics, University of SouthamptonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/486832015-12-16T19:29:43Z2015-12-16T19:29:43ZElectronics are getting small, and that is causing big problems<figure><img src="https://images.theconversation.com/files/103258/original/image-20151126-23847-m85z4v.jpg?ixlib=rb-1.1.0&rect=420%2C346%2C4101%2C2773&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The microprocessors on this wafer of silicon have transistors measuring in the nanometres.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Your television, computer, smartphone or any other electronic device wouldn’t work without being able to shuttle electric charges around their circuits.</p>
<p>Yet, as these devices gain in performance, with their individual components getting smaller and smaller – reaching the nanoscale – it becomes increasingly difficult to precisely channel these electric charges to where they’re needed. </p>
<p>In fact, at the nanoscale, some of these components behave in very strange ways, to the point where even a single atom can influence or disrupt the flow of electrons. A better understanding and control of these nanoscale dynamics is therefore crucial to improve their function.</p>
<h2>On the edge</h2>
<p>Transistors are the basic building blocks of microchips, and are found in everything from computers, to smartphones and amplifiers. Their function fundamentally depends on how electrons flow near or at the interfaces between their metallic, insulating and semiconductor materials.</p>
<p>Transistors today can be as small as 10 nanometres wide, and they’re getting smaller. If you have a smartphone in your pocket, it most probably has more than a billion transistors within. </p>
<p>As this miniaturisation trend continues, the performance of electronic components is more and more influenced by what happens to electrons at the boundaries of materials, since the likelihood of an electron being close to an interface increases as size decreases. </p>
<p>This is like if you find yourself in a room, then the smaller the room, the higher the probability that you will be standing next to a wall. </p>
<p>A similar phenomenon also affects solar cells, which generate electricity when positive and negative charges are separated within a few nanometers at the boundary between electron donating and electron accepting materials. </p>
<p>Light-emitting diodes can work the other way around: they can generate light when positive and negative charges recombine at these boundaries. </p>
<p>Organic molecules – similar to those responsible for photosynthesis in bio-organisms – with semiconducting properties are very promising materials for devices, such as transistors, solar cells and light-emitting diodes. </p>
<p>They are cost-effective, light, flexible and versatile. Their electronic properties are tuneable, and their production consumes less energy than that of silicon. </p>
<h2>Around the islands</h2>
<p>We <a href="http://www.nature.com/ncomms/2015/151006/ncomms9312/abs/ncomms9312.html">recently investigated</a> two-dimensional nano-clusters – or “nano-islands” – of different sizes and shapes, composed of organic semiconducting molecules on a thin insulator to see how electronic properties varied at different locations on them.</p>
<p>We used a scanning tunnelling microscope to determine the atomic-scale structure and electronic properties of the organic nano-islands. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/K64Tv2mK5h4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
</figure>
<p>The measurement of these currents allows us to create an image of the surface of the material to understand where atoms and electrons are located. These measurements were so sensitive that we had to perform them at a laboratory with extremely low vibrations at the University of British Columbia, in Canada. </p>
<p>Our experiments showed that the electrons of the molecules at the edge of the nano-islands behaved dramatically differently than those in the middle. Importantly, these differences in electronic behaviour depended strongly on subtle variations of position and orientation of the molecules nearby. </p>
<p>We found that when an electron is removed at a specific location in the centre of a nano-island, the electrons of the surrounding material react, moving towards the positive charge created by the electron removal. </p>
<p>Similarly, if an electron was added, the surrounding electrons moved away from the negative charge created by the electron addition. This collective motion of electrons polarises the surrounding environment and stabilises the created charge: the charge gets <em>screened</em>. </p>
<p>In contrast, when an electron is removed or added at the boundary of the nano-island – where transfer of electrons becomes important for technological applications – the created charge is screened a lot less efficiently. </p>
<p>Think of a crowded party where suddenly someone leaves the centre of the room, creating an empty space. The people dancing around will gradually occupy this spot a lot quicker than if the person had left the edge of the room. </p>
<p>This is not entirely surprising. What is surprising, though, is the magnitude of the effect. Our findings show that the energies involved in this are very large.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/97900/original/image-20151009-9146-bflng2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">3D representation of a scanning tunnelling microscopy image of a nano-island composed of twelve organic semiconducting molecules on a thin sodium chloride film. Electrons of boundary (red) and centre (purple) molecules behave dramatically differently.</span>
</figcaption>
</figure>
<h2>Tuning at the nanoscale</h2>
<p>Our work suggests a problem for the design of efficient nanoelectronic devices. Not only do subtle features of the nanoscale structure of components induce severe electronic effects at their interfaces, but also the influence of these effects becomes more important as the size of components shrink. </p>
<p>So it is crucial to control the arrangement of atoms and molecules at the interfaces between these components, and do this with incredible precision, in order to design new technologies with optimal efficiency and functionality. </p>
<p>Our findings open the door to new engineering approaches where the electronic properties of nano-devices can be tuned by small and precise variations of their atomic-scale structure. </p>
<p>This could be achieved by <a href="https://www.youtube.com/watch?v=oSCX78-8-q0">moving atoms and molecules</a> on a surface of a material in a controlled manner. Another possible way is to use supramolecular self-assembly, where atoms and molecules interact and automatically arrange themselves in desirable patterns at the nanoscale. </p>
<p>So while the effects we have discovered present a challenge for the future of nanoelectronic devices, they also present a terrific opportunity to develop faster and more efficient communication, information and electronic technologies.</p><img src="https://counter.theconversation.com/content/48683/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Agustin Schiffrin works for Monash University. </span></em></p><p class="fine-print"><em><span>Sarah A. Burke receives funding from the Natural Sciences and Engineering Research Council (Canada), Canada Research Chairs programme, Canadian Foundation for Innovation, and the University of British Columbia. </span></em></p><p class="fine-print"><em><span>Katherine Cochrane does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>As the components in electronic devices are shrinking to the nanoscale, even a single atom out of place can disrupt their function. But this also presents an opportunity to make them even better.Agustin Schiffrin, Lecturer in Physics, Monash UniversityKatherine Cochrane, PhD candidate in Atomic Imaging, University of British ColumbiaSarah A. Burke, Assistant Professor in Nanoscience, University of British ColumbiaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/464292015-08-25T13:04:05Z2015-08-25T13:04:05ZWe can turn CO in the air into new materials – but don’t expect that to stop climate change<figure><img src="https://images.theconversation.com/files/92813/original/image-20150824-17762-1iw3cgf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>What if there were a way to suck carbon dioxide right out of the air and turn it into useful products? It might seem fantastic but scientists have actually proved it’s possible. One of the challenges with making it a viable process, however, is manufacturing products that are valuable enough to cover the high costs of extracting the carbon dioxide.</p>
<p>Some excellent new research has raised the possibility of a breakthrough in this area by using CO<sub>2</sub> directly captured from the air to produce a type of graphene, the two-dimensional form of carbon often described as a “<a href="http://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2012-2013/graphene.html">wonder material</a>”. But reported claims that this amounts to producing “<a href="http://www.engadget.com/2015/08/20/carbon-from-the-air/">diamonds from the sky</a>” are somewhat misleading.</p>
<p>There is already a significant market for CO<sub>2</sub> and products made from it, most obviously fertiliser and fuels. This process of treating the gas as a feedstock rather than a waste product is known as carbon dioxide utilisation (CDU) and usually starts by capturing CO<sub>2</sub> from industrial flue gases – exhaust from furnaces or fuel-powered generators.</p>
<h2>Drop in the ocean</h2>
<p>In 2012, carbon dioxide utilisation accounted for <a href="http://www.sciencedirect.com/science/article/pii/S2212982013000322">180 megatonnes of CO<sub>2</sub></a> that would otherwise have gone into the atmosphere, and this has been forecast to rise to 256 megatonnes in 2016. But total global greenhouse gas emissions are around 35 gigatonnes and rising, meaning other emission-reduction strategies such as energy efficiency and renewable power currently play a <a href="http://journal.frontiersin.org/article/10.3389/fenrg.2015.00008/abstract">much larger role</a>.</p>
<p>Sucking CO<sub>2</sub> directly from the air can be a trickier process compared to more concentrated sources such as flue gases. As CO<sub>2</sub> represents just 0.04% of the atmosphere, you have to treat very large amounts of air just to produce even modest quantities of the gas. However, <a href="http://airfuelsynthesis.com">several companies</a> have managed to design chemical processes that are more efficient than those used in flue gas capture and produce enough <a href="http://www.climeworks.com/">industrial CO<sub>2</sub></a> to be economically viable.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=458&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=458&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=458&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=576&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=576&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92815/original/image-20150824-17765-ev7w68.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=576&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Carbon nanofibres: cylindrical layers of graphene.</span>
<span class="attribution"><a class="source" href="https://en.wikipedia.org/wiki/Timeline_of_carbon_nanotubes#/media/File:FlyingThroughNanotube.png">Wikimedia Commons/Magnus Manske</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>The <a href="http://pubs.acs.org/doi/abs/10.1021/acs.nanolett.5b02427">new research</a> from George Washington University in the US demonstrates a way to directly capture CO<sub>2</sub> from the air and turn it into carbon nanofibres, powered just by a few volts of solar electricity and solar heat. These smaller-than-microscopic structures are effectively irregular cylinders made from layers of graphene and can be used to strengthen materials for building aircraft, wind turbines and even sports equipment.</p>
<p>The researchers claim their new manufacturing method is much cheaper than existing techniques and so could open up new uses for the nanofibres. If they can scale the process up to the level of mass production and keep it cost-effective, this would really help grow the market. But a robust life-cycle analysis is needed to substantiate these claims.</p>
<p>If the technique does prove to be a cheap way of mass-producing carbon nanofibres, could it become so widely used that it significantly reduces atmospheric CO<sub>2</sub> levels, a claim <a href="http://www.technologyreview.com/news/540706/researcher-demonstrates-how-to-suck-carbon-from-the-air-make-stuff-from-it/">attributed to the authors</a> (but not in the peer-reviewed paper)? Current production of carbon nanofibres is around <a href="http://bit.ly/1JwBoXt">500 tonnes a year</a> and predicted to increase to around <a href="http://www.cnt-ltd.co.uk/services-events/market-reports/production-and-application-of-carbon-nanotubes-carbon-nanofibers-fullerenes-graphene-and-nanodiamonds-a-global-technology-survey-and-market-analysis/">10,000 tonnes a year</a>. But this is still far from the hundreds of millions of tonnes that would be needed to make a meaningful contribution to greenhouse gas levels.</p>
<h2>Starting point</h2>
<p>It is difficult to see at this time how a market for carbon nanofibres could develop to these levels. One exception might be if the price of nanofibres became so low we could start using it to cost-effectively strengthen building materials. This would also provide an interesting addition to current techniques that turn CO<sub>2</sub> and other chemicals and waste products <a href="http://www.theengineer.co.uk/in-depth/analysis/solid-as-a-rock-mineralising-carbon-dioxide/1008376.article">into stable solids</a>.</p>
<p>Developing viable direct air capture techniques is a major research challenge that will hopefully one day have far-reaching impact. It could help make CO<sub>2</sub> a resource that is available anywhere in the world where a capture unit can be installed. Carbon nanofibres will play a part in the portfolio of technologies that make up carbon dioxide utilisation, again an area that is growing in application and promise.</p>
<p>Sadly it’s most unlikely this interesting breakthrough will be scaled up to limit climate change in the way that has been claimed. We believe that due to the size of the potential market, carbon nanofibres alone will not be able to make a significant impact on CO<sub>2</sub> mitigation. However, many transformative technologies and materials start with a niche area before moving into more mainstream uses. And perhaps this could be the case for direct air capture nanofibres. After all, change has to start somewhere.</p><img src="https://counter.theconversation.com/content/46429/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Styring receives funding from EPSRC, BBSRC, European Commission</span></em></p><p class="fine-print"><em><span>Grant Wilson is a researcher with the European Smart CO2 Transformation project. <a href="http://www.scotproject.org">www.scotproject.org</a></span></em></p><p class="fine-print"><em><span>Katy Armstrong receives funding from EPSRC and European Commission.</span></em></p><p class="fine-print"><em><span>George Dowson receives funding from EPSRC</span></em></p>A new method for creating a form of graphene with carbon dioxide sucked from the air has been announced with misleading claims.Peter Styring, Professor of Chemical Engineering & Chemistry, University of SheffieldGrant Wilson, Research Associate, Environmental and Energy Engineering Research Group, Chemical and Biological Engineering, University of SheffieldKaty Armstrong, CO2Chem Network Manager, University of SheffieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/386972015-06-22T10:17:09Z2015-06-22T10:17:09ZPlasmonics: revolutionizing light-based technologies via electron oscillations in metals<figure><img src="https://images.theconversation.com/files/85396/original/image-20150617-23263-svc9sk.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The beauty of stained glass – all down to electron oscillations.</span> <span class="attribution"><a class="source" href="https://pixabay.com/en/glass-colorful-glass-mosaic-color-61087/">LoggaWiggler</a></span></figcaption></figure><p>For centuries, artists mixed silver and gold powder with glass to fabricate colorful windows to decorate buildings. The results were impressive, but they didn’t have a scientific reason for how these ingredients together made stained glass. In the early 20th century, the physicist <a href="http://dx.doi.org/10.1016/j.jqsrt.2009.02.022">Gustav Mie</a> figured out that the color of a metal nanoparticle is related to its size and the optical properties of the metal and adjacent materials.</p>
<p>Researchers have only recently figured out the missing piece of this puzzle. Medieval glass workers would be surprised to find out they were harnessing what scientists today call <a href="http://www.nature.com/nphoton/focus/plasmonics/index.html">plasmonics</a>: a new field based on electron oscillations called plasmons.</p>
<h2>Concentrating light</h2>
<p>Plasmonics demonstrates how light can be guided along metal surfaces or within nanometer-thick metal films. It works like this: on an atomic level, metal crystals have a very organized lattice structure. The lattice contains free electrons, not closely associated with the metal atoms, that interact with the light that hits them.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=266&fit=crop&dpr=1 600w, https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=266&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=266&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=334&fit=crop&dpr=1 754w, https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=334&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/85390/original/image-20150617-23223-ed35es.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=334&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Simplified sketch of electron oscillations (plasmons) at the metal/air interface. Orange and yellow clouds indicate regions with lower and higher electron concentration, respectively. Arrows show electric field lines in and outside of the metal.</span>
<span class="attribution"><span class="source">Hans-Peter Wagner and Masoud Kaveh-Baghbadorani</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>These free electrons collectively start to oscillate with respect to the fixed position of positively charged nuclei in the metal lattice. Like the density of air molecules in a sound wave, the electron density fluctuates in the metal lattice as a plasmon wave. </p>
<p>Visible light, which has a wavelength of approximately half a micrometer, can thus be concentrated by a factor of nearly 100 to travel through metal films just a few nanometers (nm) thick. That’s 1,000 times smaller than a human hair. The new mixed light-electron-wave-state empowers intense light-matter interactions with unprecedented optical properties.</p>
<h2>What can plasmonics do?</h2>
<p>Plasmonics could revolutionize the way computers or smartphones transfer data within their electronic integrated circuits. Data transfer in current electronic integrated circuits happens via the flow of electrons in metal wires. In plasmonics, it’s due to oscillatory motion about the positive nuclei. Data transfer is therefore more time-consuming in the old technology. Since plasmonic data transfer happens with light-like waves and not with a flow of electrons (electrical current) as in conventional metal wires, the data transmission would be superfast (close to the speed of light) – similar to present glass fiber technologies. But plasmonic metal films are more than 100 times thinner than glass fibers. This could lead to faster, thinner and lighter information technologies.</p>
<p>Surface plasmons also are exceptionally sensitive to any material next to the metal film. A low concentration of atoms, molecules or bacteria bound to the metal surface can change the property of its plasmons. This feature can be used for biological and chemical sensing at extremely low concentrations – for instance, to examine polluted water.</p>
<p>If properly designed, multilayers of plasmonic metal/insulator nanostructures form artificial metamaterials, where the Greek word “meta” means “beyond.” Unlike any other material in nature, these metamaterials have a negative index of refraction. That’s a measure of how much light changes its direction when it enters a transparent insulator. Insulators, including glass, have a positive refractive index; they bend light that enters at a certain angle closer to perpendicular to the insulator surface. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=549&fit=crop&dpr=1 600w, https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=549&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=549&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=690&fit=crop&dpr=1 754w, https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=690&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/85392/original/image-20150617-23256-tgr10o.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=690&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Light changes its direction when it enters a transparent insulator with positive refractive index or a metamaterial with negative refractive index.</span>
<span class="attribution"><span class="source">Hans-Peter Wagner and Masoud Kaveh-Baghbadorani</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In contrast, multilayered metamaterials bend light to the “opposite” direction. This fascinating property can be used to cloak objects by covering them with a metamaterial wrap. The foil guides the light smoothly around the object instead of reflecting it. Almost unbelievably, the cloaked object becomes invisible.</p>
<p>Other applications include optical superlenses with significantly higher resolution compared to regular optical microscopes. They could allow scientists to see objects as small as about 100 nm in size. That’s about one-tenth as big as a typical germ.</p>
<p>A few proof-of-principle optical cloaks and superlenses do exist. But high resistivity losses in the metal layers which convert the light-electron-wave energy into heat currently limit the feasibility of many applications.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=350&fit=crop&dpr=1 754w, https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=350&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/80549/original/image-20150505-943-1wicqrh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=350&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Simplified sketch of a plasmonic metal/organic/semiconductor nanowire heterostructure. The emission from the nanowire generated by the exciting laser beam is used as an energy pump to compensate for resistivity losses in the metal shell. An organic spacer layer of few 10 nm thickness is inserted to control this energy transfer.</span>
<span class="attribution"><span class="source">Hans-Peter Wagner and Masoud Kaveh-Baghbadorani</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Manufacturing plasmonic nanowires</h2>
<p>High resistivity losses are the major issue with plasmonics. To overcome these limitations, we design and fabricate unique plasmonic metal/organic/semiconductor nanowire heterostructures. Our goal is to excite the semiconductor nanowires with an external light source, then use the internal radiation in the nanowires as an energy-pump source to compensate for metallic losses. This way, the nanowires couple light energy in concert with the light-electron-oscillations to the metal film, thus restoring the amplitude of the damped plasmon wave. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/80550/original/image-20150505-951-1386s7c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Dr. Hans-Peter Wagner, right, and his doctoral student Masoud Kaveh-Baghbadorani in the organic molecular beam deposition (OMBD) laboratory, Department of Physics, University of Cincinnati.</span>
<span class="attribution"><span class="source">Jay Yocis University of Cincinnati</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We use the organic molecular beam deposition (OMBD) method to coat the semiconductor nanowires with metal/organic multilayers. In the OMBD chamber, organic and metal materials reside in heatable cylindrical cells. We evaporate both organic molecules and metal atoms in heated cells at ultra-high vacuum (which is hundreds of billion times lower than atmosphere pressure). Then we direct the molecular and atom beams we have produced toward the semiconductor nanowire sample. The thickness of the resulting deposited film on the nanowire is controlled by mechanical shutters at the cell openings. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=448&fit=crop&dpr=1 600w, https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=448&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=448&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=563&fit=crop&dpr=1 754w, https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=563&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/85547/original/image-20150618-23232-1s8on1q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=563&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Transmission electron microscope (HRTEM) image of a GaAs-AlGaAs core-shell nanowire coated with nominally 10 nm aluminum quinoline and a 5 to 10 nm thick gold cluster film on top.</span>
<span class="attribution"><span class="source">Melodie Fickenscher (Advanced Materials Characterization Center College of Engineering and Applied Science) University of Cincinnati</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The energy-transfer processes from the optically excited semiconductor nanowire to the plasmon oscillations in the surrounding metal film are studied with <a href="http://dx.doi.org/10.1088/2053-1591/2/4/045001">ultrafast spectroscopic techniques</a>.</p>
<p>Results from our studies will provide a new understanding of light-electron-waves in the novel and unique metal-semiconductor environment. Hopefully, we will open new prospects for designing low-loss or loss-free plasmonic devices. Ideally we want to enable new and important applications in information technologies, biological sensing and national defense. We further envision our investigations having a strong impact in other research fields: for instance, by utilizing the biocompatibility of our hybrid organic/metal structures, by enhancing the light emission in light-emitting diodes and laser structures or by improving light harvesting in photovoltaic devices.</p><img src="https://counter.theconversation.com/content/38697/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Hans-Peter Wagner has received research funding from the National Science Foundation in the past.</span></em></p><p class="fine-print"><em><span>Masoud Kaveh-Baghbadorani receives funding from University of Cincinnati Graduate Scholarship, The Mary J. Hanna and Henry Laws Research Fellowships.</span></em></p>The field of plasmonics has implications for integrated circuits, biosensors, other light-based technologies – even invisibility cloaks.Hans-Peter Wagner, Associate Professor of Physics, University of Cincinnati Masoud Kaveh-Baghbadorani, PhD Candidate in Physics, University of Cincinnati Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/321542015-03-19T03:34:23Z2015-03-19T03:34:23ZFinding an affordable way to use graphene is the key to its success<figure><img src="https://images.theconversation.com/files/75163/original/image-20150318-2147-wyqnpp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Graphene powder can be manufactured.</span> <span class="attribution"><span class="source">Dr Mohammad Choucair</span>, <span class="license">Author provided</span></span></figcaption></figure><p><a href="https://theconversation.com/au/topics/graphene">Graphene</a> is a remarkably strong material given it’s only a single carbon-atom thick. But finding ways to do something with it – that’s also affordable too – have always been a challenge.</p>
<p>Scientists have long been excited about the potential for graphene to revolutionise technologies, and even consider it a technology itself. Graphene is the best known conductor of electricity and heat. It is also the thinnest surface and represents the next generation wonder material for everyday applications in electronics. </p>
<p>The 2010 Nobel Prize in Physics was awarded to <a href="http://www.nobelprize.org/nobel_prizes/physics/laureates/2010/">Konstantin Novoselov and Andre Geim</a> for their pioneering work on the electronic properties of graphene.</p>
<p>There followed much hype in the science world with concepts to revolutionise <a href="http://www.sciencedaily.com/releases/2015/02/150202114303.htm">electronic displays</a> and <a href="http://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/graphene-circuit-competes-headtohead-with-silcon-technology">circuitry</a>. These two areas form the basis of many technologies so the impact of graphene was extensive. </p>
<h2>How to make graphene</h2>
<p>For such applications, graphene had to be industrially produced as large thin films on a supporting material. This highlighted two avenues where graphene could be directed: as an electronic component; or as the chief technology. </p>
<p>But these directions were rather narrow, as they only focused on potential commercial exploits involving the <a href="https://theconversation.com/samsung-heats-up-wearable-tech-race-with-graphene-wafers-25399">electronics industries</a>. </p>
<p>Exaggerated demand for graphene to be commercialised quickly outpaced the overlapping challenges concerning the processing of nanomaterials. As such, despite all the excitement, graphene has not yet found widespread use because it is chemically difficult to process. </p>
<h2>Let chemistry find a use</h2>
<p>In 2009 I developed the first technique to <a href="http://www.nature.com/nnano/journal/v4/n1/full/nnano.2008.365.html">chemically produce graphene</a> in industrial scale quantities.</p>
<p>It was clear chemistry had a key role to play in the future use of the material. We could now create gram and kilogram quantities of the graphene sheets atom by atom using chemical reactions. </p>
<p>My work has led to many attempts by researchers world-wide to find more viable techniques to produce graphene. Each attempt reaching out to be inventive, quirky, or more innovative over the prior art.</p>
<p>We found an avenue where expensive apparatus was no longer required and graphene powder could be transported with an extended shelf life. This is now a common goal among researchers.</p>
<p>This development overcame a key tenant which was overlooked during the physics era: graphene is essentially a material which is all surface. The interface at a surface is where exciting things occur and where chemists operate. </p>
<p>To do something useful with a surface you need a lot of it, and we now had a lot of graphene. The options to obtain a lot of graphene material are simple. Either start by digging graphite out of the ground from natural deposits, or you make it chemically in the lab.</p>
<p>Chemically produced graphene offers a relatively large amount of surface to perform exciting chemical reactions. This is equivalent to having a nice smooth football field to move a football around on.</p>
<h2>Non-sticky stuff this graphene</h2>
<p>But changing the chemical structure of graphene while retaining its superb physical properties is incredibly difficult. This is due to a paradox that allows for the very existence of graphene: the remarkable stability of the graphene surface. </p>
<p>Molecules like metals and gases required for energy storage simply do not stick to graphene. Imagine if everything you placed on your table simply kept falling off – the table would not be of much use.</p>
<p>Attempts to change the chemical nature of graphene focused on attaching a small number of molecules. This has limited the utilisation of graphene in nanotechnologies, as the next generation of batteries, solar energy films and fuel cells involve more complex chemical reactions.</p>
<p>Applications that would see graphene used in these technologies would require molecules with versatile chemistry stuck to graphene. </p>
<h2>Get boron onboard</h2>
<p>Together with my colleagues, we have created a new <a href="http://pubs.rsc.org/en/content/articlelanding/2014/cc/c4cc04521a#!divAbstract">graphene hybrid material</a> by directly attaching boron clusters to the graphene surface.</p>
<p>The trick was to use the stable conjugated network in graphene to trap a highly reactive boron cluster. Attaching these kinds of chemicals unlocks entirely new and interesting material properties, such as improved functionality and hierarchically organised responsiveness.</p>
<p>For example, the material may now soon be used to interact with biological molecules, harvest sunlight for use in solar cells, and anchor metals for efficient hydrogen storage. </p>
<p>The work will provide an insight into how graphene materials retain their function after large scale processing. We can now perform exact chemical reactions on graphene that will ultimately translate into more reliable and affordable graphene-based technologies. </p>
<p>We have pushed the boundaries at the nanoscale and started to find new ways to create materials from the ground up with fascinating properties that can be commercialised.</p><img src="https://counter.theconversation.com/content/32154/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mohammad Choucair does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>There is much excitement about graphene, a material only a single carbon-atom thick, but finding ways to do something with it that’s affordable have always been a challenge.Mohammad Choucair, Research Fellow, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/333692014-10-29T06:00:25Z2014-10-29T06:00:25ZTo make gas-absorbing ‘sponges’, start with a whole lotta holes<figure><img src="https://images.theconversation.com/files/62854/original/ddmjvm2q-1414386527.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When a material is mostly nothing, you can do interesting things with it.</span> <span class="attribution"><span class="source">WildBear</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p><em>The Prime Minister’s Prizes for Science – awarded at Parliament House in Canberra tonight – recognise excellence in science and science teaching. This year, we asked four prizewinners to reflect on their work and factors that influenced their careers. The Malcolm McIntosh Prize for Physical Scientist of the Year, <a href="https://wiki.csiro.au/display/MOFS/Matthew+Hill">Dr Matthew Hill</a> from CSIRO, takes us through his work in metal organic frameworks.</em></p>
<hr>
<p>Looking back, a career in science was always on the cards. When I was about four, for behaving myself I wanted to be allowed to add lots of numbers up. Growing up in Western Sydney, we didn’t have much, and a long university degree didn’t really match the budget. </p>
<p>What made the difference was my mother deciding that my sister and I were going to university no matter what, even though no one in our family had gone before. </p>
<p>As I headed to university, I thought I’d be a mathematician, but it turned out I just wasn’t quite good enough. I also really enjoyed chemistry, so I got into a labcoat.</p>
<p>My PhD at UNSW with <a href="http://www.chemistry.unimelb.edu.au/professor-robert-lamb">Rob Lamb</a> got me fired up about linking fundamental chemistry to an applied problem – what I was working on could one day be useful outside the lab. </p>
<p>When I joined CSIRO, <a href="http://www.csiro.au/Portals/About-CSIRO/Who-we-are/Executive/Executive-Team/AnitaHill.aspx">Anita Hill</a> had a great thing going with porous materials – we were interested in anything with lots of holes in it. It made sense to work with what had the most holes – that was the best way to break new ground. </p>
<p>Metal organic frameworks, or MOFs, are metal atoms joined to each other by organic linkers. When the chemistry is right, they form a structure that looks like a building scaffold. From the outside, they look like a sugar or salt crystal, but inside, every atom in the structure is exposed to empty space, meaning that up to 80% of the crystal is empty – made up of nothing. </p>
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<a href="https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=438&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=438&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=438&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=550&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=550&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62634/original/r2nzbys7-1414065041.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=550&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The remarkable structure of metal organic frameworks (MOFs).</span>
</figcaption>
</figure>
<p>All of those atoms inside the structure exposed to empty space make for a huge amount of surface. Many MOFs have over 5,000 square metres of surface area per gram – like having a soccer field inside a teaspoon worth of powder. </p>
<p>First off I was inspired by chemists such as <a href="http://chemport.ipe.ac.cn/cgi-bin/chemport/getfiler.cgi?ID=UTkX3DoqcNeoEtwC5joNU1v1o3IiuaBhBYnQFvqYFzCiuNMlsoNbj9MnrrhLT8tW&VER=E">Richard Robson</a> and <a href="http://alchemy.cchem.berkeley.edu/about-the-boss.html">Jeff Long</a> who had shown you could use all this surface like a sponge. </p>
<p>For example, it is possible to soak up natural gas into a MOF. If you put this powder into a tank, it turns out you can store many times more gas in the same place as if you compressed it – the sponge effect is that strong. So, a car powered by natural gas, which could be cheaper and cleaner, could carry enough gas to drive as far as a petrol one. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62637/original/z4v6dyht-1414065692.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some of the brilliant young researchers at CSIRO.</span>
</figcaption>
</figure>
<p>My team and I designed MOFs to store huge amounts of <a href="http://pubs.acs.org/doi/abs/10.1021/ja9072707">hydrogen</a> and <a href="http://pubs.acs.org/doi/abs/10.1021/ja9036302">natural gas</a> fuel, and to capture <a href="http://onlinelibrary.wiley.com/doi/10.1002/ange.201201381/full">carbon dioxide</a> in massive quantities as well. </p>
<p>We even made a MOF sponge that could <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201206359/full">wring itself out</a> when exposed to the sun. Most of the energy used for capturing carbon dioxide goes to regenerating your capture material, so using sunlight is an attractive alternative. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/BpgeaC6f_Mo?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Gas storage in a MOF.</span></figcaption>
</figure>
<p>The other thing about MOFs is that the holes are all the same size. Like a flour sieve, the holes can separate big from small. I was interested but didn’t know much about this, so I was lucky that <a href="http://www.colorado.edu/chbe/richard-d-noble">Rich Noble</a> at University of Colorado Boulder let me visit for a while to learn. </p>
<p>We thought that adding these MOF powders to polymer membranes – thin plastic sheets – would help one gas to pass through faster than another. It’s the best way to get natural gas, oxygen or water ready for us to use. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=659&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=659&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=659&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=828&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=828&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62639/original/9gvtgwrf-1414066578.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=828&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Anti-ageing MOF membranes.</span>
</figcaption>
</figure>
<p>Sure enough, we saw an improvement, but we also stumbled upon an even more exciting effect. These plastic sheets don’t last very long, collapsing down on themselves – they age. After a few weeks the gases don’t go through very fast any more. </p>
<p>We found that one specific MOF seemed to form a special mixture, propping the sheets open, making them last for <a href="http://onlinelibrary.wiley.com/doi/10.1002/ange.201402234/full">years instead of weeks</a>. Today we are developing these anti-ageing membranes for a platform of applications, from defence to agriculture and energy. </p>
<p>When I first started, making a teaspoon of a MOF was a major undertaking. We knew that they would never be useful unless large amounts could be made efficiently. </p>
<p>With <a href="http://www.pubfacts.com/author/Anastasios+Polyzos">Tash Polyzos</a> we took reaction times from 72 hours to <a href="http://www.nature.com/srep/2014/140625/srep05443/full/srep05443.html">1.2 minutes</a> using continuous flow chemistry. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=298&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=298&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=298&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=374&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=374&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62638/original/txfmws2m-1414066052.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=374&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Flow chemistry delivers MOFs in minutes.</span>
</figcaption>
</figure>
<p>This is the future of chemical synthesis because reactions happen faster and cleaner, and it was a game changer for MOFs. </p>
<p>Now we can make MOFs for a myriad of uses, but also have enough of them to make it worthwhile. </p>
<hr>
<p><em><strong>Further reading:<br>
<a href="https://theconversation.com/genetics-of-epilepsy-33469">The genetics of epilepsy: bringing hope to families</a> <br>
<a href="https://theconversation.com/epigenetic-code-cracker-33527">Epigenetic code cracker: why skin cells are skin cells and not neurons</a></strong></em></p><img src="https://counter.theconversation.com/content/33369/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Hill receives funding from the Australian Research Council (ARC) and Science and Industry Endowment Fund (SIEF). </span></em></p>The Prime Minister’s Prizes for Science – awarded at Parliament House in Canberra tonight – recognise excellence in science and science teaching. This year, we asked four prizewinners to reflect on their…Matthew Hill, Australian Research Council Future Fellow and leader of the Integrated Nanoporous Materials team, CSIROLicensed as Creative Commons – attribution, no derivatives.