Effect of surface charges of nanoparticles on response current of enzyme electrode for single use

The response current of glucose oxidase (GOD) electrode has been enhanced by the nanoparticles (NPs), but the mechanism of enhancement remains unclear. The effect of surface charges of NPs on the response current of GOD-electrode enhanced by NPs was studied by using the electrophoresis and the determination of zeta potential. The results indicate that, besides the inherent surface effect of NPs, the surface charges are essential for the enhancement of response current of enzyme electrode. More GOD molecules can be adsorbed on the surface of SiO2 NPs, because GOD molecules hold surface charge whose property was opposite to that of SiO2 NPs, but the same as that of Au NPs. When Au NPs and SiO2 NPs are mixed with the ratio of 1:1 in mol, the combined particles can carry out both functions of the two kinds of NPs, and enhance response performance of GOD-electrode greatly.