Direct electrochemistry of cytochrome c on TiO۲/Au nanocomposite modified electrode

چکیده مقاله

Direct electrochemistry between redox proteins and electrode surface has been extensively studied because of its potential application in the investigation of biomolecules [1]. Cytochrome c (Cyt. c) is an excellent model for studying the electron transfer of typical metalloproteins from a structure point of view. Due to the difficulty of direct electron transfer between Cyt c and a bare electrode, some modified electrodes were used as a tool to investigate the direct electrochemical property. The modifiers of these modified electrodes are organic [2], or inorganic [3] compounds.In the present study, we explored the ability of TiO2/Au nanocompositeto act as modifier to realize the direct electron transfer (DET) of Cyt c. The investigation on titanium dioxide (TiO2), a kind of inorganic porous material with unique construction, high surface area and high chemical stability, had shown that it could be used as an electrode material to promote electron-transfer reactions of protein. We investigated the formation of a hybrid biointerface consisting of gold-doped titanium dioxide (TiO2/Au) film and cytochrome c (Cyt c) on indium tin oxide (ITO) electrodes. The TiO2/Au 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. Cyclic voltammetry (CV) was performed to evaluate electrochemical properties of the as prepared interface. The ITO/TiO2/Au /Cyt c electrode display a pair of well-defined redox peak ( 0.06 V and 0.02 V) at pH 7.0 in phosphate buffer solution. These nanoparticles inhibit the adsorption of Cyt c onto bare electrode and act as a bridge of electron transfer between protein and electrode.