Dresden 2011 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 21: Biopolymers and Biomaterials II (with CPP)
BP 21.4: Vortrag
Mittwoch, 16. März 2011, 11:15–11:30, ZEU 260
A constitutive law for cross-linked actin networks by homogenization techniques — Denis Caillerie1, •Karin John2, Chaouqi Misbah2, Philippe Peyla2, and Annie Raoult3 — 1L3S-R, BP 53 - 38041 Grenoble Cedex 9, France — 2LSP, UJF Grenoble & CNRS, BP 87 - 38402 Saint-Martin-d'Hères, France — 3LMAP5, Université Paris Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
Inspired by experiments on the actin driven propulsion of micrometer sized beads we develop and study a minimal mechanical model of a two-dimensional network of stiff elastic filaments grown from the surface of a solid circle. Starting out from a discrete model of the network structure and of its microscopic mechanical behavior we derive a macroscopic constitutive law by homogenization techniques. We calculate the axisymmetric equilibrium state and study its linear stability depending on the microscopic mechanical properties. We find that thin networks are linearly stable, whereas thick networks are unstable. The critical thickness for the change in stability depends on the microscopic elastic constants. The instability is induced by the increase in the compressive load on the inner network layers as the thickness of the network increases. The here employed homogenization approach combined with more elaborate microscopic models can serve as a basis to study the evolution of polymerizing actin networks and the mechanism of actin driven motion.