Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 25: Membranes

BP 25.4: Talk

Friday, March 27, 2009, 11:15–11:30, HÜL 186

A solvent-free coarse-grained model for amphiphilic bilayers — •Martin Hömberg and Marcus Müller — Institut für Theoretische Physik, Georg-August-Universität, 37077 Göttingen, Germany

In recent years collective phenomena like membrane fusion or self-assembly of bilayers have attracted tremendous interest. However, atomistic simulations still cannot reach the corresponding time and length scales. Frequently coarse-grained models are employed to save computation time, among them are the solvent-free models, which reduce the amount of interactions to be computed considerably.

Here we present a flexible and computationally efficient bead-spring-model for simulating coarse-grained membranes without explicit solvent. We use a third-order expansion of a free energy functional in the density to describe non-bonded soft interactions, which include the interactions with the solvent implicitly. The expansion coefficients can be related to material properties, such as the molecular density, the compressibility or the incompatibility between the amphiphilic units.

We use DPD simulations with density-dependent forces to investigate the mechanical properties of amphiphilic bilayers, such as the bending rigidity, the area per lipid and diffusion coefficients. These results are compared to experimental data.