Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 21: Focus: Stress Relaxation in Polymers - From single molecules to biological cells (with CPP)

BP 21.7: Talk

Thursday, March 29, 2012, 11:30–11:45, C 243

Stress relaxation through crosslink unbinding in biopolymer assemblies — •Claus Heussinger — Institute for theoretical physics, University Göttingen

The cytoskeleton is a complex meshwork of long elastic filaments coupled together with the help of numerous, rather compact crosslinking proteins. An important aspect of a cytoskeletal polymer network is its dynamic nature, which allows it to react to external stimuli and adapt its internal structure and mechanical properties according to the needs of the cell. The reversible nature of crosslink binding is an important mechanism that underlies these dynamical processes.

In this contribution we devise a simple model polymer network to study the effect of network deformation on the crosslink binding processes. We evidence a discontinuous and sudden rupture transition after which the network is no longer able to resist the external load. By combining MC simulation with a necklace-type model (M. Fisher, J. Stat. Phys. (1984)) we discuss the role of the mechanical stiffness of the crosslinks and the fluctuation properties of the filaments. This allows to address the interplay of strain stiffening inherent in the entropic response of individual polymers, and strain softening due to crosslink unbinding.