GLUCOSE-SENSITIVE FIELD-EFFECT TRANSISTOR WITH ADDITIONAL NAFION MEMBRANE - REDUCTION OF INFLUENCE OF BUFFER CAPACITY ON THE SENSOR RESPONSE AND EXTENSION OF ITS DYNAMIC-RANGE

Glucose-sensitive enzyme field-effect transistors (ENFETs) were prepared by cross-linking glucose oxidase with bovine serum albumin in saturated glutaraldehyde vapour on the gate area of the ISFETs. Nafion membranes were deposited on the top of the glucose ENFETs by a spin-coating procedure. Additional Nafion membranes resulted in a substantial reduction of the effect of the buffer concentration on the ENFET's response and in an extension of the dynamic range of the sensor up to concentrations of more than 10 mM glucose. The effects of pH, buffer concentration and ionic strength were examined for the glucose ENFETs with and without NAFION membranes.