Mediated enzyme reactions: coupling biological electron transfer to electrodes with redox complexes

Donal Leech 

National University of Ireland, Galway, Department of Chemistry, University Road, Galway Galway, Ireland


Mediated enzyme reactions form the basis of many applications, ranging from biosensors, through biocatalytic fuel cells, to applications in industrial electrolysis. This presentation will review some of our efforts to date on redox mediation of enzyme reactions for such applications. Our initial research in this area focused on mediated reactions of laccases, a class of copper-based oxidase enzymes that catalyze the four-electron reduction of oxygen to water. Immobilization of the enzyme in a redox mediating hydrogel yields reagentless biosensors, as monitoring of mediated reduction currents for oxygen, present in solution, permits detection of any modulator of enzyme activity. Furthermore, co-immobilization of a redox mediator and an affinity recognition element, such as DNA or antibody, provides a generic platform for the amplified detection of complementary affinity partners (DNA or antigen) that are labelled with redox enzymes. Our studies on laccase biosensors demonstrated, also, that laccases co-immobilized in redox hydrogels can reduce oxygen at relatively high potentials and current densities, suggesting possible applications as cathodes in implantable biofuel cells when combined to oxidation of a fuel, such as glucose, at the anode.
Covalent coupling of enzymes and mediators on the electrode surface can appreciably improve the fuel cell stability. Also, improvements in the design of the redox complexes and polymers (in terms of structure and redox potential) help to increase biosensor and biofuel cell performance. Our approach to improving the stability and the performance of thse devices through tailored surface modification will be presented.

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: must be provided.


Related papers
  1. Electron transfer studies with different sugar oxidizing enzymes and osmium polymers to improve the current density
  2. Enzyme-amplified amperometric DNA hybridization assay based on bioelectrocatalysis using redox-polymer modified electrodes
  3. Modification of gold microelectrodes for detection of DNA hybridization
  4. Modification of electrode surfaces with redox complexes for biosensor and biofuel cell applications

Presentation: Keynote lecture at SMCBS'2007 International Workshop, by Donal Leech
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-08-31 12:34
Revised:   2009-06-07 00:44
© 1998-2022 pielaszek research, all rights reserved Powered by the Conference Engine