Direct Electrochemistry of Glucose Oxidase at a Gold Electrode Modified with Single-Wall Carbon Nanotubes

Abstract

The direct electrochemistry of glucose oxidase (GOD) was accomplished at a gold electrode modified with single-wall carbon nanotubes (SWNTs). A pair of welldefined redox peaks was obtained for GOD with the reduction peak potential at –0.465 V and a peak potential separation of 23 mV at pH 7.0. Both FT-IR spectra and the dependence of the reduction peak current on the scan rate revealed that GOD adsorbed onto the SWNT surfaces. The redox wave corresponds to the redox center of the flavin adenine dinucleotide(FAD) of the GOD adsorbate. The electron transfer rate of GOD redox reaction was greatly enhanced at the SWNT-modified electrode. The peak potential was shown to be pH dependent. Verified by spectral methods, the specific enzyme activity of GOD adsorbates at the SWNTs appears to be retained

The Redox Behaviour of Randomly Dispersed Single Walled Carbon Nanotubes both in the Absence and in the Presence of Adsorbed Glucose Oxidase

“…Within the pH range studied, the reduction peak potential was observed to shift cathodically with increasing pH value, with a slope of 56 mV per decade change of H + ion concentration , as shown in Figure 15. This result is in good agreement with the theoretical value of 59 mV per decade change of [H + ] for a reversible, two-proton/ two-electron process at 22 °C [16], calculated using the Nernst equation, and also with previous data published by Liang and Zhuobin [27] for adsorbed glucose oxidase on a SWCNT-modified gold electrode (48 mV/decade). Hence the pH studies confirm the stoichiometry of the FAD/FADH 2 surface redox reaction as presented in scheme 1 .…”

“…These results may be compared with data previously reported in the literature [27,28]. In this work the apparent heterogeneous electron transfer rate constants for redox proteins and enzymes such as hemoglobin (Hb), horseradish peroxidase (HRP) and Glucose Oxidase (GOx) were determined using linear potential sweep voltammetry at SWCNT modified glassy carbon electrodes to be in the range 1-2 s -1 .…”

Complete Oxidation of Glycerol in an Enzymatic Biofuel Cell

“…Current biocathode performance is such that the biocathode will likely be the limiting factor in the performance of a glycerol bioanode/oxygen biocathode fuel cell. In recent years, bioelectrochemists have shown that electrode performance can be enhanced by the use of high surface area materials such as carbon nanotubes [20,25,26]. High surface area cascaded glycerol bioanodes that contained multiwalled carbon nanotubes and single walled carbon nanotubes were tested and compared to the controls which were low surface area bioanodes that contained no high surface area support matrix.…”

Diamond nano-wires, a new approach towards next generation electrochemical gene sensor platforms

“…The attractive world of low dimensional systems, together with the fabrication of functional nanostructured arrays will play a major role in the new trend of chemical and biochemical nanotechnology. [3][4][5] Nano-wires can be used for tunable transport of electrons with electronic properties strongly influenced by little perturbations on the surface, for giant surface-to-volume ratio enhancements which are important for chemical/bio-chemical applications, and for generation of well defined molecular patterns on bio-sensor surfaces.…”