title: Superoxide radical sensing using a cytochrome c3 immobilized conducting polymer electrode.
abstract: A biosensor based on cytochrome c3 (cyt c3) has been introduced to detect and quantify superoxide radical (O2*-). Cyt c3, isolated from the sulfate-reducing bacterium (Desulfovibrio vulgaris Miyazaki F. strain), and its mutant were immobilized onto a conducting polymer coated electrodes by the covalent bonding with carbodiimide chemistry. The immobilization of cyt c3 was investigated with quartz crystal microbalance, electrochemical impedance spectroscopy, and cyclic voltammetric studies. The CVs recorded for cyt c3 and a mutant modified-electrodes showed a quasi-reversible behavior having the formal potential of about -471 and -476 mV (versus Ag/AgCl), respectively, in a 0.1M phosphate buffer solution (pH 7.0). The modified electrodes showed the surface controlled process and the electron transfer rate constants (ks) were evaluated to be 0.47 and 0.51 s(-1) for cyt c3 and mutant modified electrodes, respectively. A potential application of the cyt c3 modified electrode was evaluated by monitoring the bioelectrocatalytic response towards the O2*-. The hydrodynamic range of 0.2-2.7 micromole L(-1) and the detection limit of 0.05 micromole L(-1) were obtained.
authors.affiliation: Department of Chemistry and Center for Innovative Bio-physio Sensor Technology, Pusan National University, Busan 609-735, South Korea.
authors.forename: Farzana
authors.initials: F
authors.lastname: Darain
authors.forename: Jang-Su
authors.initials: JS
authors.lastname: Park
authors.forename: Hideo
authors.initials: H
authors.lastname: Akutsu
authors.forename: Yoon-Bo
authors.initials: YB
authors.lastname: Shim
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003574:Cytochrome c Group / Q000737:chemistry*; D004553:Electric Conductivity; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008839:Microelectrodes; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013481:Superoxides / Q000032:analysis*
chemical_list: D003574:Cytochrome c Group; D004800:Enzymes, Immobilized; D011108:Polymers; D013481:Superoxides; C017165:cytochrome c(3)