Hydrogen Peroxide Biosensor Based on Cytochrome c/Nano-ZnO
A nanoporous ZnO film(Nano-ZnO) was prepared by physical vapor deposited on the indium tin oxide(ITO)-coated glass plate and a new type of H2O2biosensor(cytochrome C(Cyt.c)/Nano-ZnO/ITO/CME) based on the direct electron transfer was constructed by modifying Cytochrome C on the Nano-ZnO/ITO. The XRD spectrum indicates that the Nano-ZnO has a polycrystalline hexagonal wurtzite structure; The SEM imagines shows the Nano-ZnO particles with the diameter ranging from 50 to 100 nm are mostly aggregated into larger porous form. The UV-Vis spectrum shows the absorption peak of the Nano-ZnO is at 368 nm which corresponds to the bulk value of the band gap(3.37 eV). Cyt.c was firmly absorbed on the Nano-ZnO surface and kept its activity which was confirmed by electrochemical impedance spectroscopy(EIS) and UV-Vis spectrum. The cyclic voltammetry of the Cyt.c/Nano-ZnO/ITO/CME shows the direct electron transfer between the Cyt.c and the electrod. The H2O2 biosensor shows a specific response to H2O2 in the range of 3×10-5-5×10-3 mol/L,and its sensitivity,detection limit,response time are 7.2×10-3 A·cm-2·mol/L,4×10-5 mol/L and 3 s respectively.