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AKB: Biologische Physik

AKB 40: Poster Session II

AKB 40.5: Poster

Mittwoch, 29. März 2006, 16:30–19:30, P3

Traction Force Microscopy on Elastic Layers of Finite Thickness — •Rudolf Merkel, Claudia Cesa, Bernd Hoffmann, and Norbert Kirchgessner — Institute of Thin Films and Interfaces 4, Research Centre Jülich, Germany

Most living cells adhere to solid substrates and apply sizeable mechanical forces to them. Such forces are applied predominantly at focal adhesion sites which are micron sized protein complexes in the adhesion zone. In recent years traction force microscopy was introduced as a technique to discern the force contributions of different focal adhesion sites of one cell [1,2]. Here cells are cultivated on very soft films that are deformed by cell forces. The resulting deformation fields are measured by tracking microstructures on the film surface. Data evaluation relies on the fact that forces and displacements are connected by the mechanical Greens’ tensor. Here we present expressions for the Greens’ tensor of an elastic film of finite thickness bonded to a rigid substrate. These results show distinct deviations from the Greens’ tensor of an elastic half space that has been exclusively used in this technique up to now. Moreover, we validated these results experimentally.

[1] Dembo and Wang, Biophys. J. 76 (1999) 2307.

[2] Balaban et al., Nature Cell Biol. 3 (2001) 466.