Preparation and Electrochemical Behaviors of AA-PEGMA Copolymer Film Electrode

A new kind of comblike copolymer film composed of acrylic acid-polyethylene glycol monomethyl ether acrylate copolymer(AA-PEGMA copolymer) was successfully synthesized to immobilize hemoglobin(Hb). FTIR, UV-Vis and CD spectra suggest that Hb kept its original structure in the AA-PEGMA copolymer film without denaturation. A pair of well-defined, quasi-reversible cyclic voltammetric peaks at around -270 mV vs. saturated calomel electrode(SCE) for the Hb Fe(III)/Fe(II) redox couple was observed on the film-modified electrode in phos- phate buffer solution(PBS, pH=7.0). The formal potential of Hb/AA-PEGMA copolymer film-modified electrode is linearly dependent on solution pH with a slope of -46.3 mV/pH, illustrating that one-proton transfer was accompa- nied with each electron transfer. Furthermore, the modified electrode displayed electrocatalytic response to the reduc- tion of H2O2 with a linear range of 3.5―126 µmol/L and a detection limit of 1.17 µmol/L. In conclusion, the AA-PEGMA copolymer film was proved to be an excellent matrix for the immobilization and electrochemistry of proteins.