The direct electrochemistry behavior of Cyt c on the modified glassy carbon electrode by SBA-15 with a high-redox potential

It is discovered that SBA-15 (santa barbara amorphous) can provide the favorable microenvironments and optimal direct electron-transfer tunnels (DETT) of immobilizing cytochrome c (Cyt c) by the preferred orientation on it. A high-redox potential (254 mV vs. Ag/AgCl) was obtained on glassy carbon (GC) electrode modified by immobilizing Cyt c on rod-like SBA-15. With ultraviolet-visible (UV-vis), circular dichroism (CD), FTIR and cyclic voltammetry, it was demonstrated that immobilization made Cyt c exhibits stable and ideal electrochemical characteristics while the biological activity of immobilized Cyt c is retained as usual. The electrochemistry behavior at the modified GC electrode is surface-controlled quasi-reversible process with an enhanced electron-transfer rate constant of 2.20 s(-1) because of the optimal DETT between Cyt c and SBA-15. It was also found that the modified GC electrode exhibited a predominant electrocatalytic activity for the reduction of hydrogen peroxide, which may open up a possibility for designing and fabricating enzyme electrodes with application potentials in biosensor and biofuel cells. (c) 2008 Elsevier B.V. All rights reserved.