Regensburg 2013 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 1: Cell migration

BP 1.2: Vortrag

Montag, 11. März 2013, 10:00–10:15, H43

Mechanics of Collagen Gels - What Cells Feel — •Julian Steinwachs, Claus Metzner, Stefan Münster, Nadine Lang, and Ben Fabry — University of Erlangen-Nürnberg, Germany

Collagen gels are frequently used to study cell migration in a three-dimensional environment. Their mechanical properties are governed by non-affine deformation of the collagen fibrils, such as buckling and tautening, resulting at the macroscopic scale in pronounced strain stiffening under shear and strong lateral contraction under stretch. It is currently unknown how these properties play out at the microscopic scale of a migrating cell. To explore this question, we develop a non-linear elastic material model for collagen gels based on observations from confocal microscopy that fibrils evade mechanical stress by deforming in a non-affine manner, resulting in a nonlinear force-length relationship. Our model replicates the macroscopic strain stiffening and lateral contraction of collagen and predicts that tautening of fibrils results in a strong stiffening against expanding forces that can arise, for example, when the diameter of a migrating cell is larger than the network pore diameter. Using the model, we compute cell induced stresses and local material properties during cell migration from collagen fiber displacements measured with confocal reflection microscopy. We find that mesenchymally migrating cells exert highly localized forces onto the matrix with an average magnitude of 65nN. As a result, the collagen matrix stiffens locally by approximately two-fold.