Nanocrystalline TiO2 films containing sulfur and gold: Synthesis,characterization and application to immobilize and directelectrochemistry of cytochrome c

چکیده مقاله

In this paper, nanoporous titanium dioxide (TiO2) film was used for cytochrome c (cyt c) immobilizationas an electrode substrate for electrochemical redox activity of the adsorbed cyt c. The result of cyclicvoltammetry exhibited a pair of well-defined and quasi-reversible peaks for direct electron transferof cyt c (formal potential [E0= (Epa+ Epc)/2] of 53 mV versus Ag/AgCl). In addition the effect of metaland nonmetal ions (Au, S) co-doping on the efficiency of TiO2nanoparticles (prepared by combiningsol–gel and photo-deposition methods) on the cyt c immobilization process was investigated. The resultsexhibited that the Au, S-co-doped TiO2(Au/S-TiO2) with a spheroidal shape demonstrates a smaller grainsize than the pure TiO2. Meanwhile, the UV–vis DRS of Au/S-TiO2showed a considerable red shift to thevisible region. As a result, it was found that 4% Au/0.1% S-TiO2had the highest efficiency for cytochromec immobilization. The results showed that the peak currents were higher after the annealing of the TiO2film. This observation suggests that the use of TiO2films may be advantageous for the development ofnanoporous biosensors employing reductive electrochemistry.