Dresden 2011 – scientific programme

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BP: Fachverband Biologische Physik

BP 26: Biophysics II: Mechanics and Flow in Biological Systems (joint AG jDPG, BP)

BP 26.1: Invited Talk

Thursday, March 17, 2011, 10:30–11:00, HSZ 201

The Hydrodynamics of Microswimmers — •Gerhard Gompper — Institut für Festkörperforschung and Institute of Advanced Simulations, Forschungszentrum Jülich, Jülich, Germany

Both in soft matter and in biology, there are numerous examples of swimmers and self-propelled particles. With a typical size in the range of a several micro-meters, both low-Reynolds-number hydrodynamics and thermal fluctuations are essential to determine their dynamics [1,2]. Prominent examples are sperm cells which are propelled by a snake-like motion of their tail, bacteria like E. coli which move forward by a rotational motion of their spiral-shaped flagella, and synthetic bimetallic nanorods.

We have studied the behavior of sperm cell and self-propelled rods by performing multi-particle collision dynamics (MPC) simulations, a particle-based mesoscale hydrodynamics technique which captures the hydrodynamic behavior of a wide range of complex fluids very well [3,4]. We focus here on the cooperative behavior of swimming sperm [5], and on the dynamic properties of individual sperm cells and nanorods near surfaces [6,7]. Both sperm cells and self-propelled rods display a strong surface excess in confined geometries. For rods, scaling laws for the dependence of the surface excess on the rod length and the propulsive force are derived [6].

[1] E.M. Purcell, Am. J. Phys. 45, 3 (1977).

[2] E. Lauga and T.R. Powers, Rep. Prog. Phys. 72, 096601 (2009).

[3] R. Kapral, Adv. Chem. Phys. 140, 89 (2008).

[4] G. Gompper, T. Ihle, D.M. Kroll, and R.G. Winkler, Adv. Polymer Sci. 221, 1 (2009).

[5] Y. Yang, J. Elgeti, and G. Gompper, Phys. Rev. E 78, 061903 (2008).

[6] J. Elgeti and G. Gompper, EPL 85, 38002 (2009).

[7] J. Elgeti, U.B. Kaupp, and G. Gompper, Biophys. J. 99, 1018 (2010).