We have all grown up with the idea that if a woman suspects she is pregnant she simply can pop into a pharmacy and buy a pregnancy test to use at home. Conversely, if someone suspects they are suffering from heart disease, cancer, or an infection their first instinct is to contact a GP or call an ambulance. So the obvious question is why easy-to-use self-tests have not yet been developed for life-threatening diseases.
The answer is straightforward for a scientist: it is to do with the level of the biomarker – in this case, the proteins produced by the cells in the body that are specific to the particular condition – that must be measured. Not only that but one has to measure the complexity of the biological sample – the blood or serum in the case of biomarkers. The impact of those two aspects is huge, as revealed by the very limited technological alternatives to “dipstick” tests currently available to the global healthcare market.
The “pregnancy test” is actually a great example of a dipstick test capable of detecting the presence of a pregnancy hormone called human chronic gonadotrophin (hCG) in urine, which is produced by the body after conceiving. The test uses similar chemistry to the one involved in measuring many other protein biomarkers from blood – but the measurement of protein biomarkers remains limited to bulky clinical pathology labs and companies are still struggling to miniaturise this sophisticated lab equipment.
Clinical diagnostics influences about 70% of healthcare decisions, which means they are the foundation of a cost-effective healthcare system. Life expectancy has increased massively in recent years due to remarkable developments in clinical diagnostics, these have been extensively reported in scientific literature. Diagnostic tests provide critical physiological or biochemical information that physicians or patients need for the best healthcare decisions.
So in an era when most humans struggle to live without portable computers, tablets, smartphones and the rest – why has a “personal lab” not yet been invented? Mobile computers only became possible because of major breakthroughs in battery life, transistors, integrated circuits and software development, which allowed incredible levels of miniaturisation. Clinical lab equipment needs to undergo a similar revolution to the one that led to the development of modern computers.
Decentralised diagnostics is fundamental to modern sustainable healthcare systems – but miniaturising clinical tests is often regarded as an extremely challenging task.
Several health conditions – including cancer, cardiac problems and infectious diseases – rely on extremely sensitive quantitation, the ability to actually measure the quantity of a biomarker rather than just providing a yes or no answer to its presence in blood. Diagnosis through measuring these protein biomarkers requires incredible sensitivity – that is not presently available with existing point-of-care diagnostic tests.
Effective testing at the point of care requires miniaturised technologies capable of translating complex laboratory techniques into simple and rapid tests. A number of point-of-care tests have effectively made a difference in improving the health systems. This includes the glucose test for diabetes monitoring as well as pregnancy and HIV tests. But point-of-care tests for chronic diseases such as cardiovascular diseases and cancer – which according to the World Health Organisation (WHO) were responsible for 68% of deaths in 2012 worldwide – are generally not available, despite being of key importance to early treatment and survival of patients with these health conditions.
Currently, diagnostic tests require blood samples taken from patients at medical centres or hospitals and sent to laboratories with sophisticated equipment and professional operators. The process is expensive and can take up to three weeks.
Small is beautiful
But our research group has recently demonstrated a miniaturised concept for rapid and accurate diagnosis of certain health conditions, such as myocardial infarction, sepsis and different types of cancer. This uses a low-cost plastic test strip called a Microcapillary Film and a smartphone or flatbed scanner.
The unique optical transparency of this micro-engineered material allows us to overcome the traditional barriers to signal interception – one of the most difficult components to miniaturise in a clinical pathology system – by using off-the-shelf parts. Due to the simplicity of the technology, the tests can be performed in local medical centres – or even in patient’s houses – improving health treatments and reducing patient anxiety.
The MCF is an ultra low-cost flat transparent film with a number of embedded microcapillaries. Each capillary works as a miniature reaction chamber where the blood sample is inserted and tested. After a certain reaction time, which can be 15 minutes for prostate cancer or slightly longer for myocardial infarction and sepsis, the capillaries exhibit a signal that can be detected by a smartphone or a simple flatbed scanner.
This signal can be related to certain amounts of a protein biomarker that is directly correlated with a certain health condition allowing its early detection and treatment. MCF technology provides low-cost, rapid and accurate measurement of protein biomarkers for point-of-care diagnostics, improving the speed and quality of health care decisions and patient treatments.
So let’s get our scientific and engineering minds together and revolutionise clinical diagnostics with personal labs accessible to all.