Immobilization and electrochemical redox behavior of cytochrome c on fullerene film-modified electrodes.
Two different fullerene film-modified electrodes were prepared and used for surface immobilization and electrochemical property investigation of horse heart cytochrome c (cyt c). Both a pristine fullerene film and fullerene-palladium (C(60)-Pd) polymer film-modified platinum, glassy carbon and indium-tin-oxide (ITO) electrodes were used. The immobilized cyt c was characterized by piezoelectric microgravimetry at a quartz crystal microbalance (QCM), UV-visible absorption, and X-ray photoelectron spectroscopy (XPS), as well as cyclic voltammetry (CV) techniques. The UV-visible spectral studies revealed a small blue shift of both the Soret and Q band of the heme moiety of cyt c, immobilized on the C(60)-Pd polymer film-modified ITO electrode, as compared to the bands of cyt c in solution suggesting that molecules of cyt c are densely packed onto the surface of the modified electrode. The CV studies revealed a quasi-reversible electrode behavior of the heme moiety indicating the occurrence of kinetically hindered electron transfer. A good agreement was found between the values of cyt c electrode surface coverage determined by piezoelectric microgravimetry and cyclic voltammetry. For piezoelectric microgravimetry, these values ranged from 0.5 x 10(-10) to 2.5 x 10(-10) mol cm(-2), depending upon the amount of cyt c present in solution and the time allowed for immobilization, which compared with a value of 3.6+/-0.4 x 10(-10) mol cm(-2) determined by CV. The possible mechanisms of cyt c immobilization on the C(60) film and C(60)-Pd film-modified electrodes are also discussed.
D'Souza
Francis
F
Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA. Francis.DSouza@wichita.edu
Rogers
Lisa M
LM
O'Dell
Erin S
ES
Kochman
Agnieszka
A
Kutner
Włodzimierz
W
D000327:Adsorption; D045304:Cytochromes c / Q000737:chemistry*; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry*; D037741:Fullerenes / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
D004800:Enzymes, Immobilized; D037741:Fullerenes; D010165:Palladium; D045304:Cytochromes c; C069837:fullerene C60