The preparation of hemoglobin based electrode on the basis of MOF-graphene oxide nano-complex and the investigation on its electro-catalytic effect on the reduction of H2O2

The co-mixture of graphene oxide and metal organic framework material is proposed to act as bio-macromolecule supporter. Hemoglobin based electrode is prepared via the conventional drip-casting method and heme protein molecules are incorporated into nano-complex. The role of oxygen-containing groups onto graphene oxide in the mutual interactions between elements within nano-composite as well as the integrated hemoglobin and its impact on the enzyme-involved electro-catalysis are the primary objective in the current manuscript. The analysis in the experimental results manifests that the existence of oxygen-containing groups onto GO would contribute to the improvement in the orderliness of nano-complex with hemoglobin molecule and the formation of amphiphilic micelle-like structure with hydrophobic outer surface and hydrophilic core. The mutual interaction between graphene oxide and metal organic framework would alleviate the binding strength of hemoglobin with metal organic framework to distort the aboriginal configuration of heme site within protein molecule. The synergistic effect of multiple interactions between metal organic framework and graphene oxide with oxygen-containing groups leads to the disappearance in the electro-chemical signal for the electro-active sites in graphene oxide. The interaction between elements of nano-complex would depress the electro-activity of redox sites in nano-composite and the integrated heme protein could play the role of the primary electro-active species in nano-complex with protein accommodation. The existence of oxygen-containing groups onto graphene oxide could slow down the charge transportation process via the mutual interaction between heme protein and graphene oxide to restrain the electro-catalytic efficiency. The mutual interactions between oxygen-containing groups onto GO and hetero-atoms in ZIF-67 including π-π stacking effect and hydrogen bond contribute to the maintenance in the original configuration of heme protein with the moderate electro-catalytic activity (i.e. the kinetics of charge transportation of cofactors within integrated Hb is comparable to that of the mass transferring for electro-active species in nano-complex with Hb anchoring).