Graphene nanoplatelets and horseradish peroxidase based biosensor

Horseradish peroxidase (HRP) was immobilized on the graphene nanoplatelets-(GNPs) coated glassy carbon electrode surface to realize its electron transfer. Chitosan acted as the binder. Such an interface was characterized using scanning electron microscope, voltammetry, and impedance techniques. Immobilized HRP shows a reduction peak at -0.33V vs. saturated calomel electrode (SCE), which retains high activity towards the electrocatalytic reduction of H2O2. The H2O2 sensing is workable in the range from 2.0 to 28 mu M with the detection limit of 0.6 mu M. The Michaelis-Menten model was applied to investigate HRP kinetics at such an interface. The Michaelis constant was calculated to be 0.29 mM. Such an interface is thus promising to be used as a H2O2 biosensor for different applications. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim