Studying of Electron Transfer Rate Constant of Cytochrome c Immobilized on Nanoparticle Decorated Hybrid System by Cyclic Voltammetry Technique

A hybrid of cytochrome c (cyt c) and a 4-5 nm gold nanoparticle (AuNP) on Au electrode (AuE) wasprepared. In the hybrid system, AuNPs was attached to the AuE via 1,6 hexandithiol (1,6 HDT) monolayer and cappedwith captopril (capt) molecule then electrostatically conjugated with cyt c. The AuE/AuNP/cyt hybrid system wascharacterized by cyclic voltammetry (CV). CV shows a very closely ideal protein voltammetric response with low peakseparation in both low and very high scan rates. It is suggested that on curved AuNPs, the density of immobilized cyt csmaller than AuNP free monolayer and resultant low electrostatic repulsion between cyt c molecules during reductionor oxidation. Moreover, enhancement of the interfacial electron transfer (ET) rate of AuE/AuNP/cyt system comparedwith capt/cyt c was observed. This study gave fast rate constants, 1×109cm3mol-1s-1 for bimolecular and 69.6 s-1 fortunneling ET rate constants.

کلیدواژه ها:

Cytochrome c ، Gold nanoparticle ، Captopril ، Cyclic Voltammetry ، Electron transfer Rate Constant