Direct electrochemistry and electrocatalysis of hemoglobin immobilized by methacrylic acid

The direct electrochemistry of hemoglobin (Hb) incorporated in methacrylic acid (MAA) film on a paraffin-impregnated graphite electrode (PIGE) was described. A pair of well-defined and quasi-reversible cyclic voltametric peaks are obtained. The formal potentials E-0 linearly depend on the pH of solution, indicating that the electron transfer was proton-coupled. Ultraviolet-visible (UV-Vis) spectra showed that the secondary structure of Hb in the MAA film was similar to individual Hb. The immobilized Hb retained its biological activity well and exhibited a nice response to the reduction of both NO2-, and H2O2, on the basis of which a new biosensor has been developed.