Microfabricated glucose biosensor with glucose oxidase entrapped in sol–gel matrix

Abstract

A microfabricated glucose biosensor based on an amperometeric hydrogen peroxide electrode has been developed. A sol–gel layer with 5 Å pore size and 2 μm thickness was used as the glucose oxidase entrapping 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 silver as a reference electrode. Nafion® coating was applied as the interference limiting layer. A series of technologies, such as standard photolithography, electron beam evaporation and image reverse lift-off were utilized for mass production allowing 143 electrodes to be produced at the same time. The effect of oxidable interferences was <10% of the background value of the sensor response. Calibration tests of a series of individual sensors manufactured from the same silicon wafer and dip coated in the same conditions, showed a highly reproducible response characteristics (linear range up to 500 mg dl −1 and mean sensitivity of 0.54±0.14 nA mg −1 dl −1 ( n=10)).