Fig. 2
Electrochemical characterization of the bioanode. Cyclic voltammetry (a, b) and chronoamperometry (c, d) of glassy carbon electrodes modified with the polymer multilayer system comprising an underlying P(N3MA-BA-GMA)-vio/hydrogenase layer (drop cast, a, c: [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F, DvMF-[NiFe], b, d: [NiFeSe] hydrogenase from Desulfovibrio vulgaris Hildenborough, DvH-[NiFeSe]) and an outer protection layer based on P(SS-GMA-BA)/GOx/CAT (drop cast). Working electrolyte: 0.1 M phosphate buffer (pH 7.4), a and b: scan rate: 10 mV s−1; black traces: 100% argon, red traces: 100% H2; c, d: applied potential: +160 mV vs. standard hydrogen electrode (SHE); black traces: 80% Ar and 20% H2; red traces: 75% Ar, 20% H2 and 5% O2 without glucose, blue traces: 75% Ar, 20% H2 and 5% O2 with glucose in solution (50 mM). Gray arrows in c and d indicate a change of the gas feed composition. P(N3MA-BA-GMA)-vio = poly(3-azido-propyl methacrylate-co-butyl acrylate-co-glycidyl methacrylate)-viologen; P(SS-GMA-BA) = poly(4-sytyrenesulfonate-co-glycidyl methacrylate-co-butyl acrylate); GOx; glucose oxidase, CAT; catalase
