Berlin 2005 – wissenschaftliches Programm
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AKB: Biologische Physik
AKB 100: Poster Session I
AKB 100.24: Poster
Samstag, 5. März 2005, 16:45–18:45, Poster TU D
Nonlinear Elasticity in Fibroblasts — •Pablo Fernandez, Pramod Pullarkat, and Albrecht Ott — Experimental Physik 1, Universität Bayreuth
Pulling 3T3 fibroblasts between two parallel surfaces and imposing small amplitude sinusoidal oscillations shows a crossover from a stress-independent elastic modulii regime to a stiffening one, where the elastic modulus E is approximately proportional to the average stress σ. Scaling the crossover stress σc by the zero stress elastic modulus E0 leads to a universal "crossover strain" σc / E0 ≃ 8 %. Experiments were done by sticking the cells either in a highly unspecific way (glutaraldehyde-aminosilane coating), or by means of fibronectin coating. In the first case, active responses are almost absent. The fibronectin coatings instead lead to rich active behaviour, and the stiffness and force scales are about one order of magnitude higher than with glutaraldehyde coatings. However, the stiffness-force relationship is qualitatively similar. Perturbing the cytoskeleton with specific drugs such as Latrunculin-A, ML-7 and Nocodazol strongly points towards the actomyosin system as responsible for the observed mechanical behaviour.