Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 23: Biopolymers

BP 23.8: Vortrag

Donnerstag, 25. März 2010, 12:15–12:30, H43

Tube Width Fluctuations in F-Actin Solutions — •Jens Glaser1, Dipanjan Chakraborty1, Klaus Kroy1, Inka Lauter2, Masashi Degawa2, Norbert Kirchgeßner2, Bernd Hoffmann2, Rudolf Merkel2, and Margret Giesen21Institut für Theoretische Physik, PF 100920, 04009 Leipzig — 2Insititut für Bio- und Nanosysteme, Biomechanik (IBN-4), Forschungszentrum Jülich, 52425 Jülich

Edwards’ tube model provides a simple phenomenological description of the complicated topological constraints in entangled solutions of flexible polymers. Using scaling arguments, the idea was generalized to stiff polymers with a persistence length larger than the characteristic arclength between mutual collisions, which plays the role of the entanglement length in this context. Their large contour and persistence lengths have opened the possibility of direct microscopic visualizations of the tube by superimposing snapshots of a fluorescent test filament. We determine the statistics of the tube width in F-actin solutions, beyond the usually reported mean value [1]. The experimental observations are explained by a segment fluid description based on the binary collision approximation (BCA) [2]. In this systematic generalization of the standard mean-field approach, effective polymer segments (“entanglons”) interact via a potential representing the topological constraints. The theory is complemented by Brownian dynamics and Monte Carlo simulations.
[1] J. Glaser et al., arXiv:0910.5864
[2] D.C. Morse, PRE 63:031502 (2001)

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