Regensburg 2007 – scientific programme
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BP: Fachverband Biologische Physik
BP 15: Biopolymer Solutions and Networks
BP 15.5: Talk
Tuesday, March 27, 2007, 16:15–16:30, H44
Mechanics of bundled semiflexible polymer networks — •Oliver Lieleg1, Mireille Claessens1, Claus Heussinger2, Erwin Frey2, and Andreas Bausch1 — 1Lehrstuhl für Biophysik E22, Physik-Department, Technische Universität München, D-85747 Garching, Deutschland — 2Arnold Sommerfeld Zentrum für Theoretische Physik und CeNS, Physik-Department, Ludwig-Maximilians-Universität München, D-80333 München, Deutschland
Cell shape, mechanics and motility are mainly determined by cross-linked and bundled actin networks. Despite their importance, the mechanical function of cross-linking molecules is not well understood. As in living cells many different actin binding molecules are used simultaneously, it is necessary to study their effect in in vitro systems. As we present here, above a critical concentration of the actin binding protein fascin, a solution of actin filaments organizes into a network of bundles. This structural transition is characterized by the competition between confinement energy and binding enthalpy. The mechanical response of the bundled network can be fully understood in terms of cross-linked bundles that consist of loosely coupled filaments and undergo non-affine bending undulations. Moreover, the mechanical properties of actin/fascin bundle networks can be described by a single pair of master curves over almost eight orders of magnitude in rescaled frequency. This remarkable finding can be attributed to the coarsening, self-similar network-structure.