D'Souza Francis, Rogers Lisa M, O'Dell Erin S, Kochman Agnieszka, Kutner Włodzimierz
Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0051, USA.
Bioelectrochemistry. 2005 Apr;66(1-2):35-40. doi: 10.1016/j.bioelechem.2004.03.013.
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.
制备了两种不同的富勒烯薄膜修饰电极，并将其用于马心细胞色素c（cyt c）的表面固定化及电化学性质研究。使用了原始富勒烯薄膜以及富勒烯 - 钯（C(60)-Pd）聚合物薄膜修饰的铂电极、玻碳电极和氧化铟锡（ITO）电极。通过石英晶体微天平（QCM）上的压电微重力分析、紫外 - 可见吸收光谱、X射线光电子能谱（XPS）以及循环伏安法（CV）技术对固定化的cyt c进行了表征。紫外 - 可见光谱研究表明，与溶液中cyt c的谱带相比，固定在C(60)-Pd聚合物薄膜修饰ITO电极上的cyt c血红素部分的Soret带和Q带均出现了小的蓝移，这表明cyt c分子紧密堆积在修饰电极表面。CV研究表明血红素部分呈现准可逆电极行为，这表明发生了动力学受阻的电子转移。通过压电微重力分析和循环伏安法测定的cyt c电极表面覆盖度值之间具有良好的一致性。对于压电微重力分析，这些值范围为0.5×10(-10)至2.5×10(-10) mol cm(-2)，这取决于溶液中cyt c的含量以及固定化所允许的时间，与之相比，通过CV测定的值为3.6±0.4×10(-10) mol cm(-2)。还讨论了cyt c在C(60)薄膜和C(60)-Pd薄膜修饰电极上固定化的可能机制。
