Graphene–polyamidoamine dendrimer–Pt nanoparticles hybrid nanomaterial for the preparation of mediatorless enzyme biosensor

A novel inorganic–organic hybrid nanomaterial was prepared by anchoring (3-glycidyloxypropyl)trimethoxysilane at the surface of graphene oxide, further cross-linking with polyamidoamine G-4 dendrimer, and final decoration with platinum nanoparticles. A glassy carbon electrode was coated with this hybrid nanomaterial and then used as support for the covalent immobilization of glucose oxidase. This enzyme electrode was employed to construct a mediatorless glucose amperometric biosensor. The resulting biosensor exhibited good electrocatalytical activity for the oxidation of the H2O2 produced by the enzyme catalyzed reaction, being able to detect glucose when poised at +400 mV. The biosensor showed a wide linear response to glucose ranging from 10 μM to 8.1 mM, high sensitivity of 24.6 mA/M cm2 and low detection limit of 0.8 μM. The biosensor was successfully tested for the quantification of glucose in samples of commercial soft drinks.