Direct electron transfer and electrocatalysis of hemoglobin immobilized on graphene–Pt nanocomposite

A novel hemoglobin (Hb) electrode has been presented through adsorbing Hb onto graphene–Pt nanocomposite. The graphene–Pt with uniform sheet-like structure was obtained by microwave-assisted method. Positions of Soret absorption band showed Hb retained its natural configuration after adsorption onto graphene–Pt. The electrochemical behavior of the immobilized Hb was studied by cyclic voltammetry. The immobilized Hb showed a pair of stable and well-defined peaks at the formal potential of −0.26 V. As a model, a kind of novel third generation biosensor for H2O2 was developed. The resultant heme-protein electrode exhibited electrocatalytical responses to the reduction of H2O2, excellent stability, interference and good reproducibility. The presence of graphene enhanced the protein loadings, accelerates interfacial electron transfer and improves thermal stability of the adsorbed protein.

► Graphene–Pt nanocomposite with uniform sheet-like structure was obtained by microwave-assisted method. ► Kind of novel third generation biosensor for H2O2 was developed through adsorbing Hb onto graphene–Pt nanocomposite. ► The biosensor exhibited electrocatalytical responses to the reduction of H2O2, excellent stability, interference and good reproducibility.