Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 26: Poster: New Perspectives of Scattering at Soft Matter
CPP 26.4: Poster
Mittwoch, 28. März 2012, 11:00–13:00, Poster A
Subsurface influence on the structure of protein adsorbates revealed by in situ X-ray reflectivity — •Hendrik Hähl1, Florian Evers2, Samuel Grandthyll1, Peter Loskill1, and Karin Jacobs1 — 1Saarland University, Experimental Physics, D-66041 Saarbrücken — 2Condensed Matter Physics Laboratory, Heinrich Heine University Düsseldorf, D-40225 Düsseldorf
The adsorption process of proteins to surfaces is governed by the mutual interactions between proteins, solution and substrate. Interactions arising from the substrate are usually attributed to the uppermost atomic layer. This “actual surface” defines the surface chemistry and hence steric and electrostatic interactions. For a comprehensive understanding, however, also the interactions arising from the bulk material have to be considered.
High energy X-ray reflectivity measurements enable the in situ determination of the density profile of the formed protein film. The results of these experiments clearly reveal the influence of the subsurface material on the adsorbing proteins via van der Waals forces. Thereby, the used set of functionalized silicon wafers enables a distinction between effects of the surface chemistry and the subsurface composition of the substrate: Whereas the surface chemistry controls whether or not the individual proteins are denatured, the strength of the van der Waals forces affects the final layer density and hence the adsorbed amount of proteins. The results imply that van der Waals forces mainly influence surface processes, which govern the structure formation of the protein adsorbates, such as surface diffusion or spreading.