Electron transfer reaction of poly(ethylene oxide)‐modified hemoglobin on the ITO electrode in solid polymer electrolytes

Abstract

AbstractHemoglobin (Hb) was chemically modified with poly(ethylene oxide) (PEO) to prepare PEO‐Hb. This PEO‐Hb was cast onto the ITO (Indium Tin Oxide) electrode, and the modified electrode was then soaked in PEO oligomer solution containing 0.2 m KCI. PEO‐Hb was electrochemically reduced by applying a negative potential (ranging from −0.5 to −1.2 V vs. Ag). Electron transfer between adjacent PEO‐Hbs in the cast layer was considered to be slow. Higher salt concentration and more negative potential gave an effective reduction of PEO‐Hb in PEO oligomers. Re‐oxidation of the reduced PEO‐Hb was also carried out by giving positive potential. This redox reaction was confirmed as reversible by potential polarity charge. A similar redox reaction was carried out in dry poly(oligo(oxyethylene) methacrylate) containing KCl. Polymer electrolytes were revealed to be effective polymer solvents for the redox reaction of PEO‐modified hemoglobin cast on the ITO electrode.