21st Century Diagnostics

By 2030, 23.5 percent of Europe’s population will have had their 65th birthday (1,2). And aging is not just a European problem; the World Health Organization (WHO) estimates that the proportion of deaths worldwide caused by chronic diseases will rise from 59 percent in 2002 to 69 percent in 2030 (3). Some infectious diseases too are increasing in frequency, and the combined burden of chronic and infectious disease is predicted to be an increasingly significant issue, both for public healthcare systems and – through their negative effect on gross domestic product – for the broader economy.

All chronic diseases need a long-term response from a range of health professionals, but most healthcare systems are structured around reference hospitals, which may not always be the most efficient way of dealing with such conditions. However, engineers now are working with doctors to develop new diagnostic tools, and medically-focused application of nanotechnology and microelectronics is enabling new strategies and interventions for chronic disease. In particular, investigators are developing point-of-care (POC) devices that allow home-based monitoring of patients’ conditions. These tools may lead to disease management programs that will empower the patient and help to establish cost-effective, integrated care models.

But, how can micro/nanotechnology help? The first step in most diagnostic procedures is plasma extraction from whole blood; traditionally, this is done in a clinical laboratory, which will use a centrifuge to process several milliliters of blood per patient. Micro/nanotechnology, however, employs microfluidic circuits – “lab-on-a-chip” microchips – that can separate plasma from a single droplet of blood and subsequently process microliter-scale samples of fluid. This paves the way for performing multiple tests from a single droplet of blood in a 1×1cm2 chip. Initially, researchers focused on applying the lab-on-a-chip to plasma-based diagnostic procedures, because of its ability to minimize the amount of sample required and provide rapid results. But there are other diagnostic procedures involving complex biological fluids (for example, sputum in tuberculosis diagnosis, or biopsies in cancer diagnosis) that can benefit from small samples and/or low sample dilution and greater cell concentration.

At present, diagnosing cancer and assessing treatment response can be slow and painful, and it is often inaccurate. After physical examination by an oncologist, it requires lengthy analysis including laboratory screening of a multitude of potential treatments, which is costly. Furthermore, these techniques typically are available only in special clinics. Initiating the treatment – as well as obtaining the results – can often take a long time and patients need to make multiple visits to the clinic before a treatment is considered effective. Similar problems occur with tuberculosis diagnosis. Doctors and patients really need accurate, rapid diagnostic tools that are affordable, simple and able to generate same-day results at the POC. When a return visit is required to access test results, time to treatment is prolonged, and default rates are significant. As with cancer, tuberculosis diagnosis is dependent on obtaining an adequate biological sample. For both cancer and tuberculosis, therefore, microfluidic chips may be of benefit through their ability to concentrate the samples efficiently, and separate the fluids for diagnosis; they can even test several treatments on the same chip to check their likely efficacy against a single sample.

Overall, POC devices based on micro/nanotechnology strive to optimize diagnostic and treatment routes. They shorten the clinical decision path, offering a quick and accurate means of selecting the best treatment for a particular disease. And the benefits are substantial, and include minimization of resource usage, waiting times, patient pain and healthcare costs. In my view, these miniaturized, microfluidics-based monitoring devices can really help ease the healthcare burden that we face globally, while improving patient quality of life.