Fabrication and application of glucose biosensor enhanced by ZnO nanoparticles

ZnO nanoparticle has good biocompatibility, and is suitable for enzyme immobilization. In this study, glucose oxidase (GOD) was immobilized in the multiple membrane matrix consisting of ZnO nanoparticles and polyvinyl butyl (PVB) by a sol-gel method on Pt wire substrate, and then linked by glutaradehyde. In this way a glucose biosensor was completed. The amperometric measurement of this biosensor was carried out with a double-electrode system, in which enzyme electrode served as working electrode and Ag/AgCl electrode as reference electrode. A background current in phosphate buffer soluiton, and a response current in glucose solution were obtained. So the difference between background current and response current was the current response of the enzyme electrode. The experiment results showed that GOD was firmly immobilized on the surface of electrode, and the current response was 100 times larger than that without nanoparticles. The current response maintained 70% of original response after the electrode was repeatedly used 46 times. The fabrication of electrode is simple and easily operated. Further, it was found that 35 degrees C and pH 6.8 are the set of optimal parameters for the fabrication of the electrode and the behavior of enzyme electrode appeared fine when mixed solvent of alcohol to isopropanol was 1:1.