Berlin 2005 – wissenschaftliches Programm

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AKB: Biologische Physik

AKB 100: Poster Session I

AKB 100.45: Poster

Samstag, 5. März 2005, 16:45–18:45, Poster TU D

Optical rheology of fibroblasts overexpressing different constituents of the actin cytoskeleton — •Karla Müller, Frank Sauer, Stefan Schinkinger, Jens Gerdelmann, and Josef Käs — Universität Leipzig, Fakultät für Physik und Geowissenschaften, Abteilung Physik der weichen Materie, Linnéstr. 5, 04103 Leipzig

The Optical Stretcher is a laser trap formed by two counter propagating divergent IR laser beams with tunable output power designed to determine the optical deformability of soft biological objects such as eukaryotic cells. Our initial results lead to the hypothesis that overexpression of actin filaments only in conjunction with the overexpression of an actin cross linking protein lead to significant cell stiffening. The rheological properties of cells can be determined by directly imposing a time, i.e. frequency, dependent stress on cells and monitoring the corresponding deformation, i.e. strain. From the measured data the complex shear modulus can be directly determined. The cell’s elasticity and viscosity can be traced back to its molecular roots being a highly dynamic network of cytoskeletal polymers. In the talk, the rheological data presented will be compared to stress relaxation experiments performed with the optical stretcher and to other methods such as bead rheology or SFM techniques.