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AKB: Biologische Physik

AKB 10: Cytoskeleton and Polymer Networks

AKB 10.2: Hauptvortrag

Montag, 8. März 2004, 10:00–10:30, H40

Microrheology of Actin Networks — •Andreas Bausch — Lehrstuhl fuer Biophysik E22, TU Muenchen

The actin cytoskeleton is of outstanding importance for the proper functioning of cells. In order to study the underlying physical properties of the actin polymer networks it is important to determine the mechanical properties of these semiflexible polymer networks in vitro. Here, we measure the viscoelasticity of entangled F-actin over length scales between 1 and 100 µ m using one- and two-particle microrheology and directly identify two distinct microscopic contributions to the elasticity. Filament entanglements lead to a frequency-independent elastic modulus over an extended frequency range of 0.01 to 30 rad/sec; this is probed only with one-particle microrheology. Longitudinal fluctuations of the filaments increase the elastic modulus between 0.1 and 30 rad/sec at length scales larger than the filament persistence length; this is probed by two particle microrheology.