Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 21: Intracellular Transport

AKB 21.7: Talk

Thursday, March 30, 2006, 12:15–12:30, ZEU 260

Anomalous diffusion and viscoelasticity in living cells due to crowding — •Matthias Weiss and Gernot Guigas — Cellular Biophysics Group (BIOMS), Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 580, 69120 Heidelberg

Using fluorescence correlation spectroscopy (FCS) we show that (inert) macromolecules and gold beads exhibit anomalous diffusion in the cytoplasm and nucleoplasm of living cells. By accompanying these observations with model simulations and in vitro experiments it is demonstrated that this behavior is a generic consequence of ’molecular crowding’ [1]. In other words, the anomality of the diffusion yields a quantifiable measure for the ’crowdedness’ of a fluid on the molecular scale. Based on the observation of anomalous diffusion, we determine experimentally the ’nanorheology’ of the cell’s interior, i.e. we find that the cytoplasm and the nucleoplasm are strongly viscoelastic for frequencies above 1 kHZ with a typical elasticity of about 100 Pa.

[1] Weiss, Elsner, Kartberg, Nilsson, Biophys. J. 87, 3518 (2004).