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BP: Fachverband Biologische Physik
BP 7: Posters: Cell adhesion, mechanics and migration
BP 7.28: Poster
Monday, March 31, 2014, 17:30–19:30, P3
Migration, Force Generation and Mechanocsensing of Cells in Collagen Gels — •Julian Steinwachs1, Claus Metzner1, Stefan Münster1, Katarina Aifantis2, Kai Skodzek1, and Ben Fabry1 — 1Lehrstuhl für Physikalisch Medizinische Technik - Friedrich Alexander Universität Erlangen-Nürnberg — 2Department of Civil Engineering and Engineering Mechanics - University of Arizona
Collagen gels are frequently used to study cell migration in a 3-D environment. Mechanical properties of collagen gels are governed by non-affine deformation of the fibrils, such as buckling and tautening, resulting at the macroscopic scale in strain stiffening under shear and a strong lateral contraction under stretch. It is currently unknown how these macroscopic properties play out at the scale of a migrating cell, and how this depends on cell geometry. We develop a non-linear elastic material model for collagen gels based on observations from confocal microscopy that fibrils can evade mechanical stress using their internal degrees of freedom. The tautening of fibrils results in a strong material stiffening against expanding forces. By this mechanism, even a soft collagen gel can sterically constrain a migrating cell. We compute cell traction forces from collagen fiber displacements during the migration of carcinoma cells through dilute and dense collagen gels. We find that cells exert highly localized forces that lead to long-ranging collagen displacements and little material stiffening. At the same time, the average traction force magnitude increases for denser collagen gels. This observation may explain why cells can migrate more efficiently in stiffer gels, despite their narrower pore diameter.