Dresden 2006 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 9: Chemical Bonds and Adsorption

AKB 9.4: Vortrag

Dienstag, 28. März 2006, 11:45–12:00, ZEU 260

Kinetics of Protein Adsorption at liquid/solid interfaces: A Monte Carlo study — •Markus Bellion and Ludger Santen — Fachrichtung Theoretische Physik, Universität des Saarlandes, 66041 Saarbrücken

We investigate by means of extensive Monte Carlo simulations the protein adsorption at liquid/solid interfaces. Proteins are modelled as colloidal particles. The particle-particle and the particle-surface interactions are described in the framework of the DLVO theory, which considers steric repulsion, electrostatic and van der Waals interactions. In order to investigate the time evolution of the surface coverage in agreement with the experimental setup (see contribution of H. Mantz, A. Quinn, A. Nagel and K. Jacobs for comparison), we use a layered three dimensional simulation box. In the upper layer a grandcanonical ensemble is applied, which controls the concentration of proteins in the solution. In contrast, the particle number is conserved in proximity to the liquid/solid interface.

In agreement with the experimental results we find the aggregation of a protein monolayer. If we include the possibility of conformational changes, we are able to reproduce the experimentally observed three stepped kinetics: a fast linear increase of the adsorbed amount for low coverages is followed by a second linear regime before saturation of the surface coverage sets in. The second linear regime can be understood as a collective transition from a conformation which is stable on the single-particle level to a conformation that optimizes adsorbed amount at the surface.