Electrochemical Studies of Cytochrome c on Electrodes Modified by Single‐Wall Carbon Nanotubes

Abstract

AbstractSingle‐wall carbon nanotubes (SWNTs) modified gold electrodes were prepared by using two different methods. The electrochemical behavior of cytochrome c on the modified gold electrodes was investigated. The first kind of SWNT‐modified electrode (noted as SWNT/Au electrode) was prepared by the adsorption of carboxylterminated SWNTs from DMF dispersion on the gold electrode. The oxidatively processed SWNT tips were covalently modified by coupling with amines (AET) to form amide linkage. Via Au—S chemical bonding, the self‐assembled monolayer of thiol‐unctionalized nanotubes on gold surface was fabricated so as to prepare the others SWNT‐modified electrode (noted as SWNT/AET/Au electrode). It was shown from cyclic voltammetry experiments that cytochrome c exhibited direct electrochemical responses on the both electrodes, but only the current of controlled diffusion existed on the SWNT/Au electrode while both the currents of controlled diffusion and adsorption of cytochrome c occurred on the SWNT/AET/Au electrode. Photoelastic Modulation Infared Reflection Absorption Spectroscopy (PEM‐IRRAS) and Quartz Crystal Microbalance (QCM) were employed to verify the adsorption of SWNTs on the gold electrodes. The results proved that SWNTs could enhance the direct electron transfer process between the electrodes and redox proteins.