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BP: Fachverband Biologische Physik

BP 16: Biological Membranes I

BP 16.6: Talk

Tuesday, March 15, 2011, 12:00–12:15, ZEU 260

Atomistic Simulations of Hydration Forces between Biological Surfaces — •Emanuel Schneck, Felix Sedlmeier, and Roland Netz — Technical University of Munich

Biological surfaces interact via a complex interplay of various forces, some of which still elude a quantitative theoretical description. For instance, the experimentally observed repulsion between hydrophilic surfaces at short distances, known as hydration repulsion, is not yet fully understood, despite its crucial role in controlling the equilibrium distance between biomembranes. In this study we use atomistic molecular dynamics simulations to quantify the water-mediated repulsion between extended hydrophilic surfaces as a function of their distance. By using a novel method, based on the determination of the pressure-dependent chemical potential of water between the surfaces, we obtain pressure-distance relationships with very high accuracy. For rigid surfaces we find oscillations in the repulsion strength, originating from the discrete nature of water molecules. For soft surfaces we find a monotonic increase in the repulsion strength with decreasing water layer thickness. The latter case resembles the interaction of soft, hydrophilic biomembrane surfaces. Here, our results show quantitative agreement with experiments over the whole data range.