Dresden 2011 – scientific programme

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BP: Fachverband Biologische Physik

BP 30: Posters: Physics of Cells

BP 30.25: Poster

Thursday, March 17, 2011, 17:15–20:00, P3

Nonlinear Cellular Deformation Response to Optical Forces — •Tina Händler, Tobias Kießling, Roland Stange, and Josef Käs — University of Leipzig, Germany

A number of diseases are caused by alterations in the cytoskeleton, a highly dynamic protein network that spans the whole cell. The mechanical properties of the cytoskeletal proteins determine the cellular mechanics. Therefore, changes in these proteins are reflected in the cells' response to an applied stress. With an Optical Stretcher, global deformation behavior of suspended cells can be investigated. Optically induced forces are employed to mechanically characterize cells over a wide range of stress, accounting for the proteins' distinct elastic properties depending on their concentration and the mechanical stress they are subject to. At very small stresses, most cells show a linear deformation behavior that is dominated by the actin cortex. Being subject to larger stresses, cells are deforming non-linearly even at relatively small stresses, resulting in a rupture-like, visible restructuring of the cytoskeleton. However, the cells do not completely lose their mechanical integrity, indicating that other cytoskeletal components might account for the cells' viability after the rupture event under physiological circumstances. Modifying the cytoskeletal proteins with chemical agents allows a differentiated investigation of the observed phenomena and helps to understand how cells regulate their mechanical properties.