Role of charges for the protein resistance of self-assembled monolayers

• Applicant: Dr. Peter Heinig
• Subject Area: Biological and Biomimetic Chemistry
• Term: Funded in 2004
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5430125

Materials resistant towards adsorption of proteins from biological media are of crucial importance in biotechnology and biomedical applications (e.g. implants resistant towards the adsorption of bacteria). Thin films exposing poly-(PEG) and oligo(ethylene glycol) (OEG) are materials with excellent protein repulsive properties and within the focus of research. While protein repulsion in the case of PEG can be accounted to dehydration effects and steric confinement, the mechanism of protein in the case of densely packed OEG-terminated self assembled monolayers (SAMs) is not understood. The present proposal will systematically investigate the role of salt ions (charges) as a possible mechanism of protein repulsion. The idea arises from recent experimental studies which led to the hypothesis that protein resistance is related to electrostatic effects in those systems. Protein resistance is expected to express it self by a protein-depletion zone close to the substrate and - related to that - by a typical concentration profile of salt ions. Within the present project the breakdown of the protein depletion zone and the charge profile will be measured in dependence of several parameters, as temperatur, pH, ion-type and salt concentration. Anomalous X-ray scattering techniques on modern synchrotron facilities and in addition - other techniques for molecular thin film research, as atomic force microscopy, spectroscopie ellipsometry and neutron reflectivity will be used.

• DFG Programme: Research Fellowships
• International Connection: France