Active transport on random filament networks

Condensed Matter lunchtime seminar

Active transport on random filament networks

  • Event time: 1:00pm
  • Event date: 15th November 2010
  • Speaker: Philip Greulich (Formerly School of Physics & Astronomy, University of Edinburgh)
  • Location: Room 2511,

Event details

I present a model for active transport of particles on disordered random networks of polarized filaments evolving by stochastic dynamics. The model captures the basic features of directed vesicle transport on dynamically evolving microtubules and actin filaments. Interactions of filaments are neglected and dynamics are homogeneous and isotropic. Due to mutual obstruction, the formation of particle clusters at filament (quasi-)intersections is observed. We show that, in contrast to regular networks, the cluster size distribution appears to be scale free. This is due to a preferential attachment principle.

Since dynamics are completely homogeneous in space, there is no net bias of filament orientations for periodic boundary conditions. However, confining boundary conditions induce a self-organization towards a polarized structure despite unbiased dynamics and the absence of gradients. This leads to a separation and accumulation of vesicle species following the geometry of the cell volume. The phenomenon can be understood by an analogy to electrostatics. For realistic geometries the model reproduces vesicle agglomerations as can be experimentally observed.

This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..

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