College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China.
Anal Chem. 2010 Mar 15;82(6):2253-61. doi: 10.1021/ac9021055.
The photoelectrochemical detection method is a newly developed and promising analytical method for biosensing. In this work, photoactive TiO(2) nanotubes (TNs) immobilized with horseradish peroxidase (HRP) were prepared and used for visible-light-activated photoelectrochemical detection of H(2)O(2). TNs were fabricated by anodic oxidation of titanium substrate and possessed large surface areas, good uniformity and conformability, and high porosity, which were favorable for enzyme immobilization. Electrochemical and UV-vis spectroscopic measurements demonstrated that TNs provided excellent matrixes for the adsorption of HRP and the adsorbed HRP effectively retained its bioactivities. The photocurrent spectra of HRP/TNs showed an obvious photocurrent response under visible-light irradiation (lambda > or = 400 nm), suggesting the possibility of photoelectrochemical detection of H(2)O(2) upon visible-light irradiation. It was found that the generated photocurrent of HRP/TNs at 400 nm was significantly enhanced after the addition of H(2)O(2) in solution and the photocurrent intensity increased with the increase of the H(2)O(2) concentration. The HRP/TNs electrode displayed a linear range of 5.0 x 10(-7)-3.5 x 10(-5) M and a low detection limit of 1.8 x 10(-7) M for H(2)O(2) determination. Thus, the protein-immobilized TNs would be expected to be a novel photoactive material for photoelectrochemical biosensing. This proposed strategy may open a new avenue for the applications of nanotubular TiO(2) in visible-light-activated photoelectrochemical biosensing, which could largely reduce the destructive effect of UV light and the photoholes generated by illuminated TiO(2) to biomolecules.
光电化学检测方法是一种新开发的、有前途的生物传感分析方法。在这项工作中，制备了固定辣根过氧化物酶（HRP）的光活性 TiO2 纳米管（TNs），并将其用于可见光激活的 H2O2 光电化学检测。TNs 通过钛基底的阳极氧化制备，具有大的表面积、良好的均匀性和一致性以及高的孔隙率，这有利于酶的固定。电化学和 UV-vis 光谱测量表明，TNs 为 HRP 的吸附提供了极好的基质，并且吸附的 HRP 有效地保留了其生物活性。HRP/TNs 的光电流谱在可见光照射下（lambda > or = 400nm）显示出明显的光电流响应，表明在可见光照射下有可能进行 H2O2 的光电化学检测。结果发现，溶液中添加 H2O2 后，HRP/TNs 的光电流显著增强，并且光电流强度随 H2O2 浓度的增加而增加。HRP/TNs 电极对 H2O2 的测定显示出 5.0 x 10(-7)-3.5 x 10(-5) M 的线性范围和 1.8 x 10(-7) M 的低检测限。因此，固定蛋白质的 TNs 有望成为光电化学生物传感的新型光活性材料。这种策略可能为纳米管 TiO2 在可见光激活的光电化学生物传感中的应用开辟新的途径，可以大大减少 UV 光和被照射的 TiO2 产生的光穴对生物分子的破坏性影响。
