Electron Transfer from Diamond Electrodes to Heme Peptide and Peroxidase

摘要

Direct electron transfer from boron-doped diamond elec-trodes to heme undecapeplide and horseredish peroxi-dase (HEP) was examined and evaluated for the applica-lion to 11202 biosensors. As-grown and oxygen plasma-treated diamond electrodes on which heme peplide is adsorbed exhibited cathodic current responses to 11202 on the basis of the direct electron transfer. In a compara-live study of carbon electrodes on which heme peplide was adsorbed, an oxygen plasma-treated diamond elec-trode exhibited responses comparable with those of an edge-oriented pyrolytic graphite (EOPG) electrode, de-spite much smaller roughness. However, electron transfer to compounds I and II of HRP from the diamond elec-trodes was much slower than that from EOPG or glassy carbon, su~esling that the ~r electrons of an sp2 carbon may play an important role in the direct electron transfer to the heme moiety of HIRP. To examine the applicability of heme peplide-modified diamond electrodes to oxidase-based biosensors, anodic current responses o(the oxygen plasma-treated diamond electrode to possible inta*rhig agents, ascorbic acid and uric acid, u~re exanined ~ compared with those of EOPG. Since the dimmd dee-trode exhibited much less sensitivity to those intusfrimg agents, the heme peplide-modified diamond dechode should be a promising 11202 biosensor for the qiplicodon to oxidase-based biosensors.