title: Direct electrochemistry and electrocatalytic activity of cytochrome c covalently immobilized on a boron-doped nanocrystalline diamond electrode.
abstract: Cytochrome c (Cyt c) was covalently immobilized on a boron-doped nanocrystalline diamond (BDND) electrode via surface functionalization with undecylenic acid methyl ester and subsequent removal of the protecting ester groups to produce a carboxyl-terminated surface. Cyt c-modified BDND electrode exhibited a pair of quasi-reversible and well-defined redox peaks with a formal potential (E(0)) of 0.061 V (vs Ag/AgCl) in 0.1 M phosphate buffer solution (pH 7.0) and a surface-controlled process with a high electron transfer constant (ks) of 5.2 +/- 0.6 s(-1). The electrochemical properties of as-deposited and Cyt c-modified boron-doped microcrystalline diamond (BDMD) electrodes were also studied for comparison. Investigation of the electrocatalytic activity of the Cyt c-modified BDND electrode toward hydrogen peroxide (H2O2) revealed a rapid amperometric response (5 s). The linear range of response to H2O2 concentration was from 1 to 450 microM, and the detection limit was 0.7 microM at a signal-to-noise ratio of 3. The stability of the Cyt c-modified BDND electrode, in comparison with that of the BDMD and glassy carbon counterpart electrodes, was also evaluated.
authors.affiliation: Laboratory of Organic Optoelectric Functional Materials and Molecular Engineering, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhou
authors.forename: Jinfang
authors.initials: J
authors.lastname: Zhi
authors.forename: Yousheng
authors.initials: Y
authors.lastname: Zou
authors.forename: Wenjun
authors.initials: W
authors.lastname: Zhang
authors.forename: Shuit-Tong
authors.initials: ST
authors.lastname: Lee
mesh_terms: D001895:Boron / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism*; D018130:Diamond / Q000737:chemistry*; D017097:Electric Impedance; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism*; D004952:Esters / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D013499:Surface Properties
chemical_list: D002264:Carboxylic Acids; D004800:Enzymes, Immobilized; D004952:Esters; D018130:Diamond; D006859:Hydrogen; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D001895:Boron