where he has worked since 1993. He received his Ph.D. in Solid State Physics in 1982 and his D.Sc. in Theoretical Physics in 1998. His research covers solid state physics, the physics of liquids, theory of adsorption, many-particle physics and the theory of electrochemical electron transfer. His present research is focused on the theory of electron tunneling in bridged electrochemical contacts. He is the author or co-author of more than 60 publications in scientific journals. Qijin Chi received his Ph.D. degree in analytical and physical chemistry in 1994 from the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. After having spent one year as a DFG postdoctoral fellow at Tübingen University, Germany, and two years as a JSPS postdoctoral fellow in Tokyo, Japan, he joined the Department of Chemistry at Technical University of Denmark in 1998. He is currently a lektor (associate professor) in chemistry. Qijin Chi also studied molecular biology and biochemistry (2000-2003) at the Johns Hopkins University School of Medicine. His research interests include biological nanomaterials, electrochemistry, surface self-assembled chemistry, and biophysics. He has authored four patents, over fifty research articles, and several book chapters. Tim Albrecht graduated in chemistry at the University of Essen in 2000. He received a Ph.D. with Prof. P. Hildebrandt at the Max-Planck Institute for Radiation Chemistry (now Bioinorganic Chemistry) in Muelheim/ Germany for studies on interfacial charge transfer processes of heme proteins using spectroelectrochemistry (SE(R)RS) and electrochemical STM. He held a Marie-Curie fellowship 2004-2006 whilst working in Prof. J. Ulstrup's group and became a lecturer in Physical Chemistry at Imperial College London in 2006. His research interests include (bio)electrochemistry, charge transport through individual molecules, and electrode/nanopore architectures in single-biomolecule sensing. He has published 14 research articles, 2 book chapters, and filed 2 patent applications. Palle Skovhus Jensen obtained his M.Sc. degree in 2006 at Technical University of Denmark and is presently a Ph.D. student in Prof. J. Ulstrup's group. His research includes interfacial electrochemistry, electrochemical STM and AFM of redox metalloproteins, extending to catalysis of bioelectrochemical processes by molecular scale metallic nanoparticles. He is the co-author of several research articles in these areas.

Interfacial electron transfer (ET) of biological macromolecules such as metalloproteins is the key process in bioelectrochemistry, enzymatic electrocatalysis, artificial ET chains, single-molecule electronic amplification and rectification, and other phenomena associated with the area of bioelectronics. A key challenge in molecular bioelectronics is to improve the efficiency of long-range charge transfer. The present work shows that this can be achieved by nanoparticle (NP) assisted assembly of cytochrome c (cyt c) on macroscopic single-crystalline electrode surfaces. We present the synthesis and characterization of water-soluble gold nanoparticles (AuNPs) with core diameter 3−4 nm and their application for the enhancement of long-range interfacial ET of a heme protein. Gold nanoparticles were electrostatically conjugated with cyt c to form nanoparticle−protein hybrid ET systems with well-defined stoichiometry. The systems were investigated in homogeneous solution and at liquid/solid interface. Conjugation of cyt c results in a small but consistent broadening of the nanoparticle plasmon band. This phenomenon can be explained in terms of long-range electronic interactions between the gold nanoparticle and the protein molecule. When the nanoparticle−protein conjugates are assembled on Au(111) surfaces, long-range interfacial ET across a physical distance of over 50 Å via the nanoparticle becomes feasible. Moreover, significant enhancement of the interfacial ET rate by more than an order of magnitude compared with that of cyt c in the absence of AuNPs is observed. AuNPs appear to serve as excellent ET relays, most likely by facilitating the electronic coupling between the protein redox center and the electrode surface.