Three dimensional porous graphene–chitosan composites from ice-induced assembly for direct electron transfer and electrocatalysis of glucose oxidase
Three dimensional porous graphene–chitosan (GR–CS) composites via ice-induced assembly for glucose oxidase (GOD) immobilization were reported for the first time. By adjusting the GR amount, the porous GR–CS composites containing different GR content could be produced. It was found that the GR amount played an important role in their morphologies. Higher GR amount resulted in more pores appearing in the GR–CS composites. When the GR amount was 70 wt%, the GR–CS composites (GR70–CS) had good flexibility and interpenetrating porous structures. The GR70–CS composite showed good stability, and still kept a porous structure even after dispersing and coating on the substrates. Current response from the GR70–CS composite modified glassy carbon electrode (GR70–CS/GCE) was about two times that from the bare GCE with Fe(CN)63−/4− as a probe. The direct electrochemical behavior was observed when GOD was immobilized onto the GR70–CS/GCE. The GOD modified GCE also showed good electrocatalytic activity for glucose. Using ferrocenecarboxylic acid as a mediator, a linear relationship from 0.14 to 7.0 mM (R = 0.995) between currents and the glucose concentration with a detection limit of 17.5 μM was obtained.