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Molecular Bioelectronics

Charge transport in proteins is of fundamental importance for respiration, photosynthesis, apoptosis, and many other biological processes involving redox processes. One aspect of molecular bioelectronics is the development of bio-inorganic devices that facilitate the investigation of charge transport phenomena in and across biomolecules. Furthermore, promising biological and bio-inorganic hetero-structures shall provide the basis for the development of conceptual electronic and sensing device. For this purpose, we are using crossbars for the electrically addressing of scalable protein ensembles and nanocontacts for individual molecule investigations. By this means we systematically study the charge transport in biomolecular assemblies of scalable size to elucidate the complex nature of biological charge transport with molecular accuracy.

Break junctionsEnvironmental MCBJ (left), Electrochemical MCBJ (middle), and Cryogenic MCBJ (right)

Individual Biomolecule Contacts

Break junctionWorking principle of mechanical break junction

How can the current flowing through a protein be measured? One answer to this question are nanoelectrodes with tunable gap size generated break breaking ultrathin metallic wires. The two opposing nanoelctrodes can be used as source and drain electrode and to contact individual biomolecules. Our group uses different break junction approaches to investigate charge transport in peptides and metal containing redox molecules. Break junctions have the advantage that one can tune the distance between the nanoelectrodes to the size of a single molecule with sub Ångstrom accuracy. We are attaching peptides of defined sequence with and without metal center as model protein units to the nanoelectrodes and study the electron transport through them. Our goal is to identify charge transport pathways in biomolecules and to determine the dominating charge transport mechanism.

Scalable Crossbar Junctions

Does the current flowing through parallel aligned molecules linearly scale with the molecule number? To address this question, we develop novel ensemble contacts that can measure the current transport through self-assembled mono- and multilayers of (bio)-molecules. These metal – molecule – metal junctions are fabricated by the means of Soft Lithography. The gentle printing process facilitates the fabrication of short free crossbar interconnects. The crossbar arrays are assembled from top and bottom metal electrodes with widths ranging from 10 µm down to 50 nm. The crossbars can be considered as scalable device with capabilities of addressing less than 1000 proteins in one junction. This allows narrowing the gap between single molecule and large ensemble contacts. The electrical properties of crossbar junctions can be studied by conventional IV measurements. Our goal is to scale the number of electrically addressed molecules and to compare the IV characteristics of single and multi molecule junctions. Furthermore, crossbar arrays possess great potential not only for fundamental research but also applications due to their redundant architecture and the low junction resistance in comparison to single molecule contacts.

Scalable Crossbar JunctionsWorking principle of Scalable Crossbar Junctions

Additional Information


Dr. Dirk Mayer

Tel.:  +49-2461-61-4023

More Information


D. Xiang, V. A. Sydoruk, S. A. Vitusevich, M. V. Petrychuk, A. Offenhäusser, V. A. Kochelap, A. E. Belyaev, D. Mayer, Noise characterization of metal-single molecule contacts, Applied physics letters, 106, (2015) 063702, DOI: 10.1063/1.4908252


D. Xiang, H. Jeong, T. Lee, D. Mayer, Mechanically Controllable Break Junctions for Molecular Electronics, Advanced materials 25, (2013) 4845, DOI: 10.1002/adma.201301589


D. Xiang, H. Jeong, D. Kim, T. Lee, Y. Cheng, Q. Wang, D. Mayer, Three-Terminal Single-Molecule Junctions Formed by Mechanically Controllable Break Junctions with Side Gating, Nano letters 13, (2013) 2809, DOI: 10.1021/nl401067x


N. Sanetra, Z. Karipidou, R. Wirtz, N. Knorr, S. Rosselli, G. Nelles, A. Offenhaeusser D. Mayer, Printing of highly integrated crossbar junctions, Advanced Functional Materials, 22 (2012) 1129–1135.  DOI: 10.1002/adfm.201101925, coverstory


V. A. Sydoruk, D. Xiang, S. A. Vitusevich, M. V. Petrychuk, A. Vladyka, Y. Zhang, A. Offenhäusser, V. A. Kochelap, A. E. Belyaev, D. Mayer, Noise and transport characterization of single molecular break junctions with individual molecule, Journal of applied physics 112, (2012) 014908, doi: 10.1063/1.4736558


D. Xiang, F. Pyatkov, Y. Zhang, A. Offenhäusser, D. Mayer, Gap size dependent transition from direct tunneling to field emission in single molecule junctions, Chem. Commun., 47 (2011), 4760 DOI:10.1039/C1CC10144G


D. Xiang, F. Pyatkov, F. Schröper, Y. Zhang, A. Offenhäusser, D. Mayer, Molecular Junctions Bridged by Metal Ion Complexes, Chemistry - A European Journal, 17, (2011)  13166  doi: 10.1002/chem.201102915


Z. Yi, M. Banzet, A. Offenhäusser, D. Mayer, Fabrication of nanogaps with modified morphology by potential-controlled gold deposition, Physica Status Solidi (RRL), 4 (2010) 73, DOI: 10.1002/pssr.200903417


Z. Yi, S. Trellenkamp, A. Offenhäusser, D. Mayer, Molecular junctions based on intermolecular electrostatic coupling, Chem. Commun., 46 (2010) 8014, DOI: 10.1039/c0cc02201b


Y. Liu, A. Offenhäusser, D. Mayer, Rectified tunneling current response of bio-functionalized metal–bridge–metal junctions, Biosens. Bioelectron. 25 (2010) 1173, doi:10.1016/j.bios.2009.10.001


G. Meszaros, S. Kronholz, S. Karthäuser, D. Mayer, Th. Wandlowski, Electrochemical fabrication and characterization of nanocontacts and nm-sized gaps, Appl. Phys. A 87, (2007) 569, DOI: 10.1007/s00339-007-3903-2