The effect of particle size on the direct electron transfer reactions of metalloproteins using au nanoparticle-modified electrodes

Abstract

The direct electron transfer (DET) reactions of proteins (cytochrome c [cyt c], D-fructose dehydrogenase [FDH], and bilirubin oxidase [BOD]) immobilized on electrodes coated with Au nanoparticles (AuNPs) of various sizes (particle sizes: 7nm [AuNP 7], 15 nm [AuNP 15], and 70 nm [AuNP 70]) were examined to elucidate the effect of the AuNP size. For cyt c, the reduction and oxidation currents for the AuNP 7-modified electrode were small compared to the other AuNP sizes (AuNP 15 and AuNP 70) with the same roughness factor (R f). For BOD and FDH, the AuNP 70-modified electrode had the best performance in terms of the catalytic current at the same R f. The results demonstrate that the size of spaces on the electrode surface is a very important factor governing the electron transfer reactions of proteins on an AuNP-modified electrode. © The Electrochemical Society of Japan All rights reserved.