Berlin 2008 – scientific programme

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BP: Fachverband Biologische Physik

BP 10: Self Propulsion

BP 10.1: Talk

Tuesday, February 26, 2008, 14:00–14:15, C 243

Cilia Dynamics — •Jens Elgeti and Gerhard Gompper — Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany

Cilia are hair-like extensions of some cells that propel fluid over its surface by performing a whip-like motion. Cilia appear in many places in nature, e.g. to remove mucus from the human respiratory system, or on the surface of Paramecium.

We present simulation results for a two-dimensional array of autonomously beating cilia, solely coupled by hydrodynamic interactions. These hydrodynamic interactions are sufficient to lead to synchronization of cilia motion in the form of a “metachronal wave”. We show that the metachronal wave enhances velocity and efficiency of solute transport compared to synchronously beating cilia. The transport velocity increases up to a factor of 3, when the cilia are packed more densely, while transport efficiency increases almost an order of magnitude.

Furthermore, we characterize transport and wave properties as functions of the viscosity, effective stroke direction and cilia spacing. For example, we show that the main correlation direction roughly coincides with the effective stroke direction, and that the beat frequency decreases through metachronal coordination while the energy consumption per beat is largely independent of cilia spacing, effective stroke direction, and metachronal coordination.

We believe, that for the fitness of the cell, both the efficiency and especially the transport velocity are essential. The metachronal wave pattern is thus of great functional significance for ciliated cells.