| Mark Rodgers and Paul Millner at the University of Leeds explore the role of biosensors in everything from pharmaceuticals to proteins
Blood glucose sensors are the best known biosensors, since the majority of the current commercial market is aimed at diabetics. Novel biosensors are being developed that have applications in fields as diverse as pesticide monitoring, detection of toxic agents and point-of-care medical analysis. Over the past 50 years, biosensors have evolved from electrodes with membranes holding an enzyme in place into highly accurate, compact devices for rapidly quantifying a wide range of analytes. Very few of these have yet become commercially viable, due to difficulties in producing sensors in volume with sufficient reproducibility and stability. Although there are now many types of biosensor, this article will mainly consider electrochemical biosensors. Each type of electrochemical biosensor has its own strengths and weaknesses, making them more useful for particular groups of analytes. There are also several common methods of constructing the sensing surface that confer different properties on the sensor. Careful consideration of sensor construction allows fine tuning of a biosensor’s electrical and physical properties to its analyte. The current generation of biosensors are likely to undergo continued evolution before the devices become truly widespread.
Many people come into contact with biosensors on a day-to-day basis without realising the wide range of analyses now performed by these devices. The market for biosensors has been estimated at around $5 billion globally, with approximately 85 per cent of this being for sensors to monitor glucose in diabetes (1,2). High blood glucose levels account for over two million deaths each year, including 21 per cent of ischemic heart disease and 13 per cent of ischemic stroke deaths. When added to those directly attributed to diabetes itself, the number is raised to 3.16 million globally, placing it in the top five worldwide causes of death. If this figure continues to rise steadily, 300 million people are estimated to be suffering from diabetes by 2045, and the global market for glucose biosensors is likely to increase consistently for decades.
However, biosensors are more than just glucose monitors and recently, more complex biosensors have been developed to provide an alternative to traditional testing for various medical and environmental analytes, ranging from infectious diseases to organophosphate pesticides and toxins (3). They have found uses in bacterial contamination monitoring and brewing, and are being examined as tools for military use. However, the number of commercially available biosensors is still low as the refinement of such devices is a complex and slow process (4). |
