Biosensors for Environmental and Clinical Monitoring

Biosensors are analytical devices composed of a recognition element of biological origin and a physico-chemical transducer. Immobilization plays a major role in developing the biosensor by integrating both the above components. In this article, studies carried out at BARC on immobilization of biological elements and their association with transducers for the development of biosensors for environmental and clinical monitoring, are reviewed. Biosensors for methyl parathion pesticide, catechol, glucose, urea, cholesterol and dopamine are being studied Concept of Biosensor A biosensor is a compact analytical device, incorporating a biological or biologically derived sensing element, either closely connected to, or integrated within a transducer system. The principle of detection is the specific binding of the analyte of interest to the complementary biorecognition element immobilized on a suitable support matrix (Fig. 1). The specific interaction results in a change in one or more physico-chemical properties (viz. pH change, electron transfer, mass changes, heat transfer, uptake or release of gases or specific ions) which can be detected and measured by the transducer. The usual aim is to produce an electronic signal, which is proportional to the concentration of a specific analyte or group of analytes, to which the biosensing element binds 1. Fig.1: Principle of biosensors