Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 5: Posters: Biopolymers and Biomaterials

BP 5.21: Poster

Montag, 22. März 2010, 17:15–20:00, Poster B1

Microrheology: On the comparison of the pancreatic carcinoma cytoskeleton and the in vitro assembled keratin network — •Tobias Paust¹, Anke Leitner¹, Ulla Nolte¹, Michael Beil², and Othmar Marti¹ — ¹Institute of Experimental Physics, Ulm University — ²Institute of Internal Medicine I, Ulm University

The intermediate filament cytoskeleton of pancreatic carcinoma cells is responsible for elasticity and stiffness of the cell and furthermore for shielding its nucleus. Therefore the mechanical properties of the cytoskeleton have to be determined. After polymerization the in vitro assembled keratin 8/18 networks should show similar mechanical properties depending on the ratio of components. By using microrheology methods both the intermediate and the assembled networks were analyzed and then the mechanical properties, the structure and the behaviour under stress were compared.
For this purpose Microrheology with embedded tracer beads is a suitable tool, because the size of the beads compared to the mesh size of the network allows to treat the network as a continuum and to use an analytical model. Observing the beads motion with a CCD-High-Speed-Camera with a time resolution better than 0.25ms leads to the dynamic shear modulus of the networks.
The measurements show storage moduli and the dissipative loss in the extracted cytoskeleton compared to the in vitro assembled network. This is related to differences in the structure of the network and the polymerization process. The results of this experiments will be discussed.