Biosensors at the service of medical diagnostic

Conventional methods of diagnosing disease are based on laboratory analysis of blood and urine samples. Such tests are far from ideal: they have to be carried out in analysis laboratories by highly qualified personnel, take several hours and are very expensive. It would be less intimidating for patients to have access to a simpler technique, which would enable easier and cheaper diagnosis in a more easily accessible location, such as a doctor's surgery, or even at home. This breakthrough would also be cost-effective for hospitals and health services.

Biosensor technology can meet all these requirements. The first biosensor was developed in 1962 by Clark and Lyons. Glucose oxidase (GOD) was then trapped on the surface of a platinum electrode by a dialysis membrane allowing diffusion of substrates and reaction products. This device made it possible to measure different glucose concentrations by detecting the O ₂ consumed during substrate oxidation by the enzyme. Since the pioneering work of Clark and Lyons, biosensor technology has evolved formidably. These devices have been continually refined to efficiently detect not only glucose, but also numerous biomolecules enabling the diagnosis of various pathologies. Advances in biosensor technology now allow implantable devices to be used, albeit for limited periods, in patients. This makes it possible to monitor the concentration of a molecule at a given point in the body in real time. Implantable glucose biosensors will considerably improve the quality of life of diabetic patients, who will be able to continuously monitor their blood glucose levels in the very near future.

Following an explanation of the operating principle of biosensors, this article will present the potential of these detection systems for medical diagnostics. The first part will focus on systems currently on the market, while the second will present biosensors currently under study for the diagnosis of various pathologies such as infectious diseases and cancer.