Direct electron transfer between cytochrome c and TiO۲/Ag nanocomposite electrode

چکیده مقاله

The direct electron transfer of redox proteins and enzymes is very difficult on many baresolid electrodes. Many methods and materials are used to immobilize the proteins andenzymes in order to enhance the direct electron-transfer rate and provide a suitable microenvironmentfor them [1]. Cytochrome c (Cyt c) is a very basic redox heme protein,but it is usually difficult for Cytc to transfer electron to a conventional electrode. To remedythis problem, various promoters have been employed to promotethe direct electron transfer between Cyt c and the electrode [2]. In the present study, direct electrochemistry of Cyt c, which was adsorbed on the surface of silver-doped titanium dioxide (TiO2/Ag), was investigated. The results from cyclic voltammetry (CV) suggestedthat Cyt c could be tightly adsorbed on the surface of TiO2/Ag and TiO2/Ag shows an obvious promotion for the direct electro-transfer between Cyt c and electrode. We fabricated a hybrid bio interface consisting of silver-doped titanium dioxide (TiO2/Ag) film and cytochrome c (Cyt c) on indium tin oxide (ITO) electrodes.A couple of well-defined and quasi-reversible CV peaks of Cyt c (Epa at 0.09 V and Epc at 0.02 V) can be observed in aphosphate buffer solution (pH 7.0). The TiO2/Ag film provided a good microenvironment for the immobilization of biomolecules, enhanced the surface coverage of protein, had large surface-to-volume ratio, and high stability. The results showed that TiO2/Agpromoted the direct electron transfer between Cyt c and the bare electrode.