The redox behaviour of randomly dispersed single walled carbon nanotubes both in the absence and in the presence of adsorbed glucose oxidase

The electrochemical behaviour of SWCNTs randomly dispersed on gold and glassy carbon electrode surfaces was characterised via cyclic voltammetry and complex impedance spectroscopy, using the ferri/ferrocyanide couple as a redox active test probe. In subsequent investigations glucose oxidase (GOx) was adsorbed onto the SWCNT ensemble without apparent denaturation of the enzyme. Cyclic voltammetry and potential step chronoamperometry were used to quantify and understand the process of electron transfer between the immobilised protein redox site and the working electrode. The effect of pH on the system was also investigated. In particular, we have shown that, for the calculation of electron transfer rate constants for surface-immobilised redox systems, chronoamperometry is preferable to voltammetry, which has been the technique of choice until now.