A biosensor is a device which consists of a biological sensing element connected to a transducer. The transducer can be electronic, optical, electrical, etc. This emerging technology offers us a powerful tool which is radically altering our approach to analytical methods. It was realised that enzymes are natural sensors on account of their highly selective nature. Much of the impetus to the work has come from medical requirements. Instant analysis of clinical samples has an obvious appeal to physicians and patients alike. Of particular interest is the possibility of continuous 'in-vivo' monitoring of metabolites, drugs and proteins using miniature, portable systems. In recent years, there has been a growing demand for biosensors in the fields of veterinary science, animal husbandry, the food industry and environmental monitoring. However, the possibility of successful application rests upon future developments. Increasing attention will have to be paid to the engineering of both the basic components and the device on the whole. New biochemical reactions will either have to be discovered or engineered through genetic manipulation or chemical techniques. Optimization of response time, selectivity, stability and low costs should receive priority considerations.
