Development of biosensor for glucose estimation by ion sensitive field effect technique.

In order to provide a better understanding of the Ion Sensitive Field Effect Devices (ISFED) as a biosensor, the C-V characteristics and the change in the flat band voltage of Electrolyte-Insulator-Semiconductor (Electrolyte-SiO2-Si) in response to pH are examined. The response of silicon oxynitride as an insulator to pH in EIS has better response compared to that of SiO2. The application of C-V characteristics of EIS as a biosensor for glucose estimation, is investigated. For this purpose glucose oxidase is immobilized on the surface. The change in the capacitance of this system (biased at constant voltage) to different concentrations of glucose is measured. The output response of differential capacitance shows a linear response to the variation of glucose concentration, thus providing a technique which could be used as a biosensor.