Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 25: Focus: Active Fluids

CPP 25.6: Hauptvortrag

Mittwoch, 24. März 2010, 11:45–12:15, H39

Active cytoskeletal polymer networks: from model systems to cells — •Christoph F. Schmidt — Drittes Physikalisches Institut, Georg-August-Universität Göttingen, Germany

Mechanical processes, such as cell division and growth or cell locomotion, are essential in cell life and are driven and controlled by the cytoskeleton. The polymeric components of the cytoskeleton are semiflexible polymers. Force-generating motor proteins are tightly integrated into these polymer networks which makes the cytoskeleton a prototypical "active gel".

We study mechanical properties and collective dynamics of cells and of in vitro model systems for active cytoskeletal networks with microrheology techniques. We use micron-sized probe particles, embedded in the medium to be studied, and laser optical traps to confine the particles, combined with laser interferometry to detect either their Brownian motion or the particles' response to a driving force with sub-nm accuracy and bandwidths up to 100 kHz. We have applied this technology to non-equilibrium systems and have measured, at the same time, the elastic properties and the fluctuations and forces generated by myosin motor proteins interacting with a cross-linked actin network. We have also applied the same type of approach to several types of cells, and have monitored cellular forces transmitted to externally attached probe particles.