Direct electron transfer and electrocatalysis of hemoglobin adsorbed onto electrodeposited mesoporous tungsten oxide

A novel hemoglobin (Hb) electrode has been presented through adsorbed Hb onto mesoporous tungsten oxide via one-step electrodeposition. Positions of Soret absorption band showed Hb retained its natural configuration on the resulting films. Electrochemical impedance spectroscopy and cyclic voltammetry were employed to study the electrochemical behavior of adsorbed Hb. The immobilized Hb showed a pair of stable and well-defined peaks at about −284 and −174 mV at 100 mV s−1 in pH 6.0 buffers and displayed excellent electrocatalytical responses to the reduction of H2O2, NO2- and trichloroacetic acid. The presence of meso-WO3 film greatly enhances the protein loadings, accelerates interfacial electron transfer and improves thermal stability of the adsorbed protein.