Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 16: Poster Session I
BP 16.47: Poster
Dienstag, 27. März 2007, 17:00–19:30, Poster D
Nonlinear Elasticity of Entangled Actin Networks — •Christine Semmrich1, Klaus Kroy2,3, and Andreas Bausch1 — 1Lehrstuhl für Biophysik E22, TU München, Deutschland — 2Institut für Theoretische Physik, Universität Leipzig, Deutschland — 3Hahn-Meitner-Institut, Berlin, Deutschland
The strain hardening of crosslinked actin networks is currently attracting lots of attention as a paradigm for essential mechanical properties of living cells. The elasticity of such crosslinked networks can vary by more than one order of magnitude in dependence of the applied stress. This has been attributed to the nonlinear mechanical behaviour of single filaments. In contrast, the mechanical response of purely entangled actin is often reported to be shear thinning. By means of different rheological approaches we are able to investigate the nonlinear response of purely entangled actin networks. Interestingly, under standard conditions a strain hardening occurs below a critical temperature while above this critical temperature strain softening is reported. Moreover, this transition is highly dependent on the buffer salt concentration. We suggest a simple theoretical model based on the interaction potential between single actin filaments including temperature and salt dependent effects to rationalize this behaviour.