MICROFABRICATED GLUCOSE BIOSENSOR WITH GLUCOSE-OXIDASE ENTRAPPED IN SOL-GEL MATRIX

A microfabricated glucose biosensor based on an amperometeric hydrogen peroxide electrode has been developed. A sol-gel layer with 5 Angstro m pore size and 2 mu m thickness was used as the glucose oxidase entra pping matrix. The sol-gel matrix formed over the silicon-based sensor has good mechanical and chemical stability, and the ability to entrap a large amount of enzyme. The miniaturized electrode sensing system is composed of platinum as both working and counter electrodes and silve r as a reference electrode. Nafion(R) coating was applied as the inter ference limiting layer. A series of technologies, such as standard pho tolithography, electron beam evaporation and image reverse lift-off we re utilized for mass production allowing 143 electrodes to be produced at the same time. The effect of oxidable interferences was < 10% of t he background value of the sensor response. Calibration tests of a ser ies of individual sensors manufactured from the same silicon wafer and dip coated in the same conditions, showed a highly reproducible respo nse characteristics (linear range up to 500 mg dl(-1) and mean sensiti vity of 0.54 +/- 0.14 nA mg(-1) dl(-1) (n = 10)). (C) 1998 Elsevier Sc ience B.V. All rights reserved.