Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 40: Poster Session II

AKB 40.7: Poster

Wednesday, March 29, 2006, 16:30–19:30, P3

Two-Dimensional Dynamics of a Semiflexible Polymer in Flow — •Tobias Munk and Erwin Frey — Arnold-Sommerfeld-Center, LMU München

In this poster we address the question how a single stiff polymer moves in a viscous fluid environment. The model system we refer to is the bio-polymer F-actin. The polymer is represented by a continuous two-dimensional space curve with a fixed length and a curvature-dependent bending energy. Furthermore we account for the constraint of inextensibility by introducing a Lagrange multiplier into the hamiltonian. By invoking suitable eigenfunctions we obtain a system of coupled first order stochastic differential equations of Langevin type, which can be solved numerically.

We present results for the polymer’s motion in two simple flow fields: In a shear flow, the semiflexible filament periodically tumbles. Each of these tumbling events induces a transient buckled conformation, induced by the interplay of elastic, viscous and stochastic forces. In a toggled elongational flow, we observe the dynamics of the force extension and tension propagation.

Our numerical results nicely complement recent experiments with DNA in flow. Furthermore, they predict some behaviour specific to F-actin, which is considerably stiffer than DNA, to be observed in future experiments.