Wired pyrroloquinoline quinone soluble glucose dehydrogenase enzyme electrodes operating at unprecedented low redox potential.
We report unprecedented high current densities for the enzymatic oxidation of glucose already at 0 V versus Ag/AgCl. The modified electrodes were made by assembling pyrroloquinoline quinone (PQQ)-soluble glucose dehydrogenase (PQQ-sGDH) from Acinetobacter calcoaceticus with osmium-based redox polymers and a cross-linker. Both redox mediators are made of a poly(4-vinylpyridine) (PVP) polymer with Os complexes tethered to the polymer backbone via long C chains, giving the Os complexes flexibility and mobility inside the redox hydrogels. Current densities larger than 1 mA cm(-2) were measured already below 0 V with a plateau value of 4.4 mA cm(-2). Similar hydrogel electrodes comprising the same redox polymers and glucose oxidase (GOx) showed less than half the current densities of the PQQ-sGDH electrodes. The current versus potential curve dependence showed a sigmoidal shape characteristic of mediated enzyme catalysis but with a current increase versus potential less sharp than expected. Surprisingly, the midwave redox potential was positively shifted with respect to the potential of the redox mediator.
Centre de Recherche Paul Pascal, UPR 8641, CNRS, F-33600 Pessac, France.
Victoria
V
Flexer
Nicolas
N
Mano
D004566:Electrodes; D042843:Glucose 1-Dehydrogenase / Q000737:chemistry*; D010084:Oxidation-Reduction; D045542:PQQ Cofactor / Q000737:chemistry*; D012995:Solubility
D045542:PQQ Cofactor; D042843:Glucose 1-Dehydrogenase