Electrochemical characterization of the effect of gold nanoparticles on the electron transfer of cytochrome c

Abstract In this work cytochrome c (cyt c), a heme‐containing redox protein, was used as a model system for studying general aspects of wiring proteins into conceptual metal–biomolecule–metal nanoparticle junctions. Electron transfer kinetics of cyt c immobilized on Au(111) via MUA spacer has been investigated in the absence and presence of surface‐bound gold nanoparticles. The combined effect of size and immobilization time of AuNPs as well as their binding site to cyt c on the tunnelling rate of the protein has been explored. It has been observed that electrostatic binding of 5 nm‐in‐diameter gold nanoparticles obviously accelerates the electron transfer rate of cyt c. Potential applications of gold nanoparticles as electric contacts in nanodevices as well as their beneficial or adverse health effects have been suggested. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)