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AKB: Biologische Physik

AKB 25: Cell Mechanics I

AKB 25.7: Vortrag

Donnerstag, 30. März 2006, 16:30–16:45, ZEU 260

Cytoskeletal mechanics and dynamics in living cells — •Carina Raupach, Philip Kollmannsberger, Johannes Pauli, Claudia Mierke, and Ben Fabry — Zentrum für Medizinische Physik und Technik, Henkestr. 91, 91054 Erlangen

Cytoskeletal (CSK) mechanics and dynamics are important for essential processes in living cells including crawling, division, and mechanochemical signal transduction. Here we measured the creep-response (passive mechanics) of subconfluent human vascular endothelial cells (HUVEC) and different human cancer cell lines. Step forces of ∼1 nN were generated with magnetic tweezers acting on superparamagnetic, fibronectin-coated beads bound to the cytoskeleton via cell adhesion receptors (integrins). We also measured the spontaneous motion of these beads (dynamics) and computed their autocorrelation function (AC). The AC displayed diffusive behaviour at short time scales (< 1 s) and superdiffusive behaviour at longer time scales that was well described by a power law: AC(t) = α · (t/t₀)^β. The creep response γ also followed a power law: γ(t) = a · (t/t₀)^b. We found a significant (p < 0.01) correlation between α and a, but not between the power-law exponents β and b. These data suggest that different mechanisms give rise to power-law rheology and power-law superdiffusivity.