Zinc oxide nanoparticles/glucose oxidase photoelectrochemical system for the fabrication of biosensor.

Nanosized semiconductor crystals can increase efficiency of photochemical reactions and greatly improve the catalytic activity of enzymes to generate novel photoelectrochemical systems. In this work, glucose oxidase (GOx)/zinc oxide (ZnO) is selected as a model system to assess the photovoltaic effect of semiconductor nanoparticles on the enzyme electrode. UV-spectrum and circular dichroism (CD) results show that the structure of GOx is preserved after conjugation with ZnO nanoparticles. The current response of the enzyme electrode containing ZnO nanoparticles increases from 0.82 to 21 microA cm(-2) in the solution of 10 mM beta-D-glucose. Furthermore, after irradiating the enzyme electrode with UV light for 2 h, the current response can be increased nearly 30% and the detection limit can be lowered about two orders compared with the catalytic reactions in the dark, which indicate that a technique to fabricate a novel photocontrolled enzyme-based biosensor may be developed.