Oxidation of glucose at nanostructured composite bioelectrocatalytic systems
|Marta Gierwatowska , Barbara Kowalewska , Paweł J. Kulesza|
University of Warsaw, Faculty of Chemistry, Pasteura1, Warsaw 02-093, Poland
We propose new bioelectrocatalytic system containing carbon nanotubes stabilized with 4-(pyrrole-1-yl) benzoic acid (PyBA) active towards glucose oxidation.
The presence of 4-(pyrrole-1-yl) benzoic acid in such integrated systems improves their stability and introduces new functional (carboxyl) groups which play an important role in the enzyme immobilization on surfaces of such layers. Systems with controlled composition and physicochemical properties act as good carriers and mediators for enzymes and other catalytic redox centres.
As a redox mediator, tetrathiafulvalene (TTF) has been used. The presence of TTF facilitates the effective flow of electrons from redox centres of the enzyme (glucose oxidase) to the glassy carbon electrode. Carbon nanotubes in such systems plays an important role, forming a three-dimensional "nanowire” network around the enzyme molecule, as well as they improve electronic conductivity of the bioelectrocatalytic layer. Combination of glucose oxidase, carbon nanotubes and the appropriate redox mediator has produced a system capable of effective oxidation of glucose in 0.1M phosphate buffer (pH = 7.0).
The problem of hydrogen peroxide (which is a product of glucose oxidation) has also been addressed. The use of horseradish peroxidase (HRP) and catalase (CAT), i.e. enzymes capable of H2O2 decomposition has led to increase of the overall catalytic activity during electrooxidation of glucose and shifted the oxidation potentials towards more negative values.
The proposed integrated electro-active systems towards glucose oxidation in neutral environment seem to be of great importance to the development of biofuel cells.
Presentation: Poster at SMCBS'2009 International Workshop, by Marta Gierwatowska
See On-line Journal of SMCBS'2009 International Workshop
Submitted: 2009-09-07 19:53 Revised: 2009-09-07 19:59