Berlin 2005 – scientific programme
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AKB: Biologische Physik
AKB 100: Poster Session I
AKB 100.43: Poster
Saturday, March 5, 2005, 16:45–18:45, Poster TU D
Entropic forces act as crosslinkers in entangled actin networks — •Rainer Tharmann1, Sven van Teeffelen2, A.R Bausch1, and K. Kroy2 — 1Technische Universität München, Lehrstuhl für Biophysik, James-Franck-Strasse 1, 85747 Garching, Germany — 2Hahn-Meitner-Institut, Abteilung Theorie, Glienicker Strasse 100, 14109 Berlin, Germany
Here we analyze in a rheological study that entropic forces act as effective No-dqpseudo cross linkersNo-dq (PCL) to in vitro actin networks. The addition of low concentrations of poly ethylene glycol (PEG) in entangled actin networks results in a significant increase of the moduli. Two regimes can be distinguished: at low volume fractions of PEG the increase of the moduli is small, while for concentrations of PEG higher than a critical concentration c⋆ an drastic linear increase of the moduli can be observed. This increase of the moduli is similar to the scaling with ∼ R2 (R = ccrosslinker/cactin) as it is observed with biochemical crosslinkers. In sharp contrast to specific crosslinkers the entropically pseudo crosslinked networks show a not so pronounced shear hardening behavior. This can be explained by the possibility for the filaments to slip along the contour length.