Direct Electrochemistry of Cytochrome c at Nanocrystalline Boron-Doped Diamond

Abstract

Direct electron transfer of horse heart cytochrome c is measured at a nanocrystalline boron-doped diamond thin-film electrode. A quasi-reversible, diffusion-controlled cyclic voltammetric response is observed for untreated diamond. The peak currents change linearly with the concentration, and importantly, there is no electrode fouling. The results, observed for a hydrogen-terminated and uncharged surface, (i.e., no ionizable carbon-oxygen functional groups), raise interesting questions about the necessary surface interactions of cytochrome c for relatively rapid electrode kinetics.

Ordered Mesoporous Niobium Oxide Film: A Novel Matrix for Assembling Functional Proteins for Bioelectrochemical Applications

“…Cyt-c, a structurally and electrochemically well-characterized heme protein, [18] served as a simple model. In aqueous Cyt-c solutions, the MNO-derived electrode gave a couple of redox peaks at E pc = ±74 mV and E pa = 101 mV due to adsorbed Cyt-c molecules, in comparison with the cyclic voltammograms of the bare MNO electrode in a blank buffer solution.…”

Remarkably High Heterogeneous Electron Transfer Activity of Carbon-Nanotube-Supported Reduced Graphene Oxide

“…Both electrodes exhibited well-defined voltammetric responses towards Cyt c with peak currents located around 0.04 to -0.06 V versus Ag/AgCl, consistent with the DET-type electrocatalysis of this enzyme. [30][31][32][33] We observed the electrocatalytic currents immediately upon adding Cyt c into the background electrolyte solution, and little deviation from the initial voltammetric response after multiple subsequent scans. The linear relation between the voltammetric peak current and (scan rate) 1/2 ( Figure 9b) suggested a diffusion-controlled charge transfer behavior of this enzyme on both rGO-ctrl and rGO/CNT.…”

“…[28][29] Furthermore, we find that, compared to rGO-ctrl, rGO/CNT exhibited significantly higher direct electron transfer (DET) efficiencies with two enzymes of great interest in biotechnology, cytochrome c and horse radish peroxidase. [30][31][32][33] Development of electrodes having high DET efficiencies with redox enzymes is of great interest in various potential applications such as biosensors, 33 bioelectronics, 34 enzyme catalysts 35 and biofuel cells. 36 Our study is the first investigation of the HET activities of rGO/CNT, a novel graphene system, and indicates its potential application in various electrochemical technologies.…”

“…DET Efficiencies with Enzymes. Cyt c is a DET-type enzyme studied extensively, [30][31][32][33] and it has been shown that conventional carbon electrodes, such as glassy carbon, graphitized carbon fiber, and carbon paste electrodes, show very low DET efficiencies with this enzyme. [15][16]33 Figure 9a shows representative backgroundsubtracted voltammograms of 100 µM Cyt c in 100 mM phosphate buffer solution (pH = 7.0) at different scan rates on rGO-ctrl and rGO/CNT with identical ESAs of 0.37 cm 2 each.…”

Electrochemical Biosensors for Medical and Food Applications

“…The most successful example of such sensors is the glucose sensors [124]. There are reports of such sensing systems for a-synuclein, insulin [125 -127], myoglobin [125,128], bombesin, neurotensin [129], hemoglobin [130 -132], Cytochrome c [133,134], etc. Human serum albumin (HSA) was analyzed by potentiometric stripping analysis through adsorbed anti-HSA IgG onto thick-film carbon working electrode [33].…”