基于细胞色素C/氧化锌的过氧化氢生物传感器

Hydrogen Peroxide Biosensor Based on Cytochrome c/Nano-ZnO

在铟锡氧化物(ITO)导电玻璃上,通过物理气相沉积纳米氧化锌制备了Nano-ZnO/ITO,并采用浸渍法将细胞色素C(Cyt.c)直接修饰于Nano-ZnO膜上,制得了Cyt.c修饰电极(Cyt.c/Nano-ZnO/ITO/CME),构建了基于直接电子传递的过氧化氢(H2O2)生物传感器。Nano-ZnO的X射线衍射光谱表明Nano-ZnO膜为多晶六边形纤维锌矿结构;扫描电子显微镜(SEM)表明Nano-ZnO膜为多孔纳米材料,微粒直径在50～100nm,且堆积形成多孔Nano-ZnO结构;紫外可见吸收光谱的最大吸收峰为360nm,室温禁带宽度3.37eV。交流阻抗、紫外可见光谱以及循环伏安法证明了吸附在Nano-ZnO上的Cyt.c保持了生物催化活性,并实现了在Nano-ZnO上的直接电子传递。H2O2生物传感器(Cyt.c/Nano-ZnO/ITO/CME)的线性范围5×10-5～5×10-3mol/L;灵敏度7.2×10-3A.cm-2.mol/L,检出限4×10-5mol/L;响应时间约3s。

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 HEO2biosensor（ 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 UVVis spectrum. The cyclic vohammetry 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 5×10^-5～5×10^-3mol/L, and its sensitivity, detection limit, response time are 7.2×10^-3A·cm^-2·mol/L, 4×10^-5mol/L and 3 s respectively.