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BP: Fachverband Biologische Physik

BP 27: Cell Mechanics II

BP 27.2: Vortrag

Donnerstag, 15. März 2018, 10:00–10:15, H 1028

Active prestress leads to an apparent linear stiffening of the cytoskeleton through geometrical coupling and shear-induced nematic alignment — •Elisabeth Fischer-Friedrich — Biotec, TU Dresden, Tatzberg 47-49, 01307 Dresden, Germany

Tuning of active prestress e.g. through activity of molecular motors constitutes a powerful cellular tool to adjust cellular stiffness through nonlinear material properties. Understanding this tool is an important prerequisite for our comprehension of cellular force response, cell shape dynamics and tissue organization. Experimental data obtained from cell-mechanical measurements often show a simple linear dependence between mechanical prestress and measured differential elastic moduli corresponding to a power law with exponent one. While these experimental findings could point to the theoretically predicted ``pull-out" of soft bending modes, we propose here a surprisingly simple alternative explanation. In a theoretical study, we show how active prestress in the cytoskeleton gives rise to a linear increase of measured cellular force response and resulting apparent stress-stiffening through geometrical-coupling and shear-induced nematic alignment. We argue that a new experimental paradigm is required to separate this apparent stress-stiffening from actual nonlinearities in prestressed biological materials.