Hydrodynamic manipulation of active transport along actin cortex models

• Applicant: Professor Dr. Joachim P. Spatz
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2004 to 2009
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5425288

We aim to understand how active transport along two-dimensional, semi-flexible polymer networks is mediated by flow. In particular, the investigations will focus on two-dimensional networks of actin filaments (F-actin) and F-actin bundles which mimic the actin cortex of cells. These actin cortex models are of extreme biological interest, can be easily visualized by fluorescent optical microscopy, and their stiffness can be tuned by bundling of the actin filaments to one another. Most importantly, actin filaments act as tracks for guiding active transport of cargo such as organelles or microspheres by molecular motors. In particular, we will focus on the problem of how two-dimensional actin networks at pillar interfaces are constructed in flow and how their conformations are manipulated after network assembly. Modification of transport of micro- and nanoscopic colloids as well as of F-actin bundles with and without motors along these actin cortex models under the drag of flow will then be studied. The transport problems suggested are biomimetic studies of the influence of order and randomness along two-dimensional networks of tracks and external driving force (motors, flow) on a statistical process isolate from the complicated and undetermined cellular environment. Ultimately we will use our actin cortex models to investigate a variety of interesting questions that touch issues in hydrodynamics, polymer physics (confinement of actin solutions in flow), biology (actin cortex and cellular transport mechanisms in flow) and statistical physics (polymer conformations in flow, statistics of transport on a partially disordered network).

• DFG Programme: Priority Programmes
• Subproject of: SPP 1164: Nano- and Microfluidics: Bridging the Gap between Molecular Motion and Continuum Flow
• Participating Person: Privatdozent Dr. Tamás Haraszti