Development of a (PQQ)-GDH-anode based on MWCNT-modified gold and its application in a glucose/O2-biofuel cell

In this study a biofuel cell anode is developed on the basis of multi-walled carbon nanotubes (MWCNTs). Recombinant pyrroloquinoline quinone (PQQ) dependent glucose dehydrogenase (GDH) is covalently coupled to a PQQ-layer which is adsorbed onto thiol-modified MWCNTs at a gold electrode. In the presence of glucose a catalytic current starts at a potential of -80 mV vs. Ag/AgCl, 1 M KCl. Under substrate saturation current densities of 170-200 mu A/cm(2) can be achieved. The operation is based on mediated electron transfer of the enzyme. This (PQQ)-GDH-MWCNT-electrode is combined with a MWCNT-modified electrode to which bilirubin oxidase (BUD) is covalently coupled. The resulting membrane-free biofuel cell has an open cell potential of 600 mV and can achieve a power density in the range of 23 mu W/cm(2). (C) 2010 Elsevier B.V. All rights reserved.