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

Glucose-sensitive enzyme conductometric biosensors based on interdigitated gold electrodes were prepared by cross-linking glucose oxidase with bovine serum albumin in a saturated glutaraldehyde vapour on the sensor chips. Nafion membranes were deposited on top of the glucose sensor by a spin-coating procedure. The effects of buffer concentration and ionic strength were examined for the glucose sensors with and without Nafion membranes. Additional Nafion membranes resulted in a substantial reduction of the effect of buffer concentration on the sensor response and in an extension of the dynamic range of the sensor up to a glucose concentration of more than 10 mM Moreover the comparison of the properties of the developed conductometric glucose biosensors (operational and storage stability, reproducibility of measurements) demonstrates better performance of the sensor with an additional Nafion membrane.