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 O2. 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 (eq. 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.