Dresden 2006 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 30: Poster Session I

AKB 30.30: Poster

Montag, 27. März 2006, 15:30–18:00, P1

Nonlinear Viscoelasticity of Single Fibroblasts — •Pablo Fernandez, Pramod Pullarkat, and Albrecht Ott — Experimentalphysik 1, Universität Bayreuth, Universitätsstraße 30, D-95440 Bayreuth

We perform single-cell uniaxial stretching experiments on 3T3 fibroblasts. By superimposing small amplitude oscillations on a cell under stress, we find a relation between the viscoelastic moduli and the average force. Data from different cells over several stress decades can be uniquely scaled to obtain a transition from stress-independent moduli to power law stress hardening. Remarkably, this master-relation holds independently of deformation history, adhesion biochemistry, and intensity of active contraction. We propose that it reflects the statics of the force bearing actin cytoskeleton, and show that it can be explained as strain hardening arising from actin filament bending. We also show preliminary results from frequency and amplitude sweeps. At large amplitudes, a roughly linear relation between force and length is observed, in marked contrast with the stress hardening behavior given by the master-relation. This holds irrespective of frequency in the range 0.1 – 1 Hz.