Molecular wires probing and understanding their electronic and mechanical properties (R-2151)

This proposal aims at the study of the electronic and mechanical properties of wire-shaped molecules, all with special functionalities in a biological context: DNA-fragments as carriers of the genetic information, protein-based antibodies as essential parts of the immune system, and conjugated polymers, which are able to recognize and bind biomolecules in aqueous media. Biosensors usually employ large ensembles of these molecules, but in contrast to this, we are focussing now on the behaviour of individual molecular wires. The central experimental challenge is the handling of individual molecules and the attachment of electronic contacts, which also have to serve for the mechanical manipulation. The approach will be based on the combination of own expertise (covalent immobilisation of biomolecules on solid supports) and the C-AFM technique, i.e. atomic-force microscopy with an electrically conducting tip. This will allow to unravel the various external cues (temperature, pH, salt concentration, mechanical stress), which are decisive for the conduction- and hybridisation properties of DNA in a systematic fashion. In an analogous way, we will study the conductivity properties of polymer chains and analyze the influence of bonds, which are established by recognition reactions between these polymers and proteins. Finally, we will study the molecular mechanics of antibody-antigen interactions (two proteins as binding partners) and investigate whether the binding behaviour can be manipulated by local electric fields.

Keywords:BIOMOLECULS, BIOSENSORS, ELECTRO-OPTICAL MATERIAL SYSTEMS, ELECTRONIC MATERIAL SYSTEMS

Disciplines:Physical sciences, Electrical and electronic engineering, Mechanical and manufacturing engineering