Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 32: Physics of Cells III

BP 32.2: Vortrag

Freitag, 30. März 2012, 09:45–10:00, H 1028

Insights into equilibrium shape from in-silico modeling of red blood cells — •Ulf Schiller^1,2 and Anthony Ladd² — ¹Theoretical Soft Matter and Biophysics, Institute of Complex Systems, Forschungszentrum Jülich, 52425 Jülich, Germany — ²Department of Chemical Engineering, University of Florida, Gainesville FL 32611-6005, USA

We present a novel computational model for deformable particles such as red blood cells. It is based on a finite-element like model of an elastic membrane with director degrees of freedom. The model resembles a two-dimensional liquid crystal coupled to an elastic network. We outline the connection to Helfrich's curvature model, and demonstrate how a coarse-grained worm-like chain model can account for the spectrin network elasticity. One of the advantages of our model is that we have full control over the reference state of the elastic surface. This allows us to probe its influence on the equilibrium shape of RBCs, which in most other models is implicitly built in via the parametric shape function put forward by Evans and Fung. We show simulation results that indicate that the Evans-Fung shape is not a strain-free minimum if a spherical reference configuration is used. The remaining strains drive the RBC away from the discocyte shape and into the stomatocyte shape. The discocyte shape thus requires a-priori assumptions to be stabilized, which is to be contrasted with the relaxation of remaining strains due to dynamic reorganization of the spectrin network. We discuss the relevance of these findings with respect to possible extensions of computational RBC models.