Electrochemical biosensors and nanobiosensors

Electrochemical techniques have great promise for low-cost, miniaturised, easy-to-use, portable devices for a wide range of applications – in particular medical diagnosis and environmental monitoring. Different techniques can be used for biosensing, with amperometric devices taking the central role due to their widespread application in glucose monitoring. In fact, glucose biosensing takes a share of around 70% of the biosensor market due to the need for diabetic patients to monitor their sugar levels several times a day, making it an appealing commercial market.
In this chapter we present the basic principles of electrochemical biosensor devices. A description of the different generations of glucose sensors is used to describe in some detail the operation of amperometric sensors and how the introduction of mediators can enhance the performance of the sensors. Electrochemical impedance spectroscopy is a technique being increasingly used in devices due to its ability to detect variations in resistance and capacitance upon binding events. Novel advances in electrochemical sensors due to the use of nanomaterials such as carbon nanotubes and graphene are presented as well as well as future directions that the field is taking.