Regensburg 2010 – scientific programme
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BP: Fachverband Biologische Physik
BP 23: Biopolymers
BP 23.8: Talk
Thursday, March 25, 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 Giesen2 — 1Institut 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)