Glucose ENFET doped with MnO2 powder

In this study, a glucose-sensitive enzyme field-effect transistor (ENFET) coimmobilized with glucose oxidase (GOD) and manganese dioxide (MnO2) have been investigated. The biomembrane of the ENFET was immobilized on the amorphous tin oxide/indium tin oxide glass structure extended sensitive gate, which used as a disposable transducer of a glucose biosensor. MnO2 was used as a catalyst which can catalyze the hydrogen peroxide and produced H2O and O-2. Coimmobilizaion of glucose oxidase and manganese dioxide was found to be useful for extending the dynamic measured range of glucose concentration to 360 mg/dl (eg. 20 mM). The result shows that the dynamic range of the output signal is strongly dependent on pH value of measuring environments, and the measurement in the alkali buffer solutions shows a higher response and wider dynamic range. Additionally, the different immobilized layers of MnO2 have been studied. The MnO2, which be immobilized in outer cross-linking layer of bovine serum albumin, shows better results than immobilized in GOD layer or gultaraldehyde covalent layer. (C) 2001 Elsevier Science B.V. All rights reserved.