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Updated: May 3, 2026

Simultaneous Measurement of Superoxide/Hydrogen Peroxide and NADH Production by Flavin-containing Mitochondrial Dehydrogenases
Published on: February 24, 2018
Wired pyrroloquinoline quinone soluble glucose dehydrogenase enzyme electrodes operating at unprecedented low redox
Victoria Flexer1, Nicolas Mano
1Centre de Recherche Paul Pascal, UPR 8641, CNRS, F-33600 Pessac, France.
Abstract:
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.
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