Biosensors

Increasingly biological sciences are being built on a quantitative foundation, based upon our ability to accurately determine the temporal and spatial variations in the concentration of key molecules. It is this quantitative analytical data that provides the testable basis for building hypotheses about biological systems. Although many, diverse analytical techniques have been used to collect quantitative data these are often destructive of the system being analysed. Biosensors by contrast promise the ability to measure selected molecules continuously and in real-time with good spatial resolution. They use specific molecular recognition at the surface of a transducer such that an electrical signal is generated in proportion to the concentration of the target analyte. Many different molecular recognition reagents have been exploited in this respect and include enzymes, binding proteins and nucleic acids, whilst electrochemical, optical and mass sensitive signal transduction devices have been used to generate the electrical signal (typically a voltage or current).

Using biosensors in vivo presents additional challenges over and above simply relating signal to concentration. Biocompatibility is an ever-present issue and includes both the effect of the biological matrix on the sensor as well as sensor components on the biology. In this chapter a review of the different sensing modes is presented and their potential applicability to the monitoring of cells, tissue and tissue constructs is presented.