Institution

Abstract:

We will perform mechanical simulations to mimick the contraction of cell-populated collagen gels. Eukaryotic cells embedded in gels spontaneously contract it by two orders of magnitude, a phenomenon which we have shown to result from a purely mechanical, collective boundary effect. Crucial aspects of the phenomenology are the three-dimensional geometry and the nonlinear viscoelastic response of the gel, which call for finite-element modeling. We plan to simulate cells as active "holes" applying a constant normal stress. This ansatz embodies our conception of "dumb cells in a smart matrix" and lends itself readily to theoretical work. Whereas the active behaviour of a cell is scarcely understood, the (passive) mechanical response of the surrounding collagen gel is well known. In a first stage we will use simply constitutive equations such as Neo-Hookean materials; eventually we plan to introduce exponential energy functions in order to explore the importance of physical nonlinearities.