Tissue folding driven by contractility, adhesion and viscoelastic relaxation

Embryogenesis, the process by which an embryo acquires a shape and an organisation, is a fascinating stage of the life of multicellular organisms in which the genetic programme harnesses mechanical forces to achieve controlled large-scale deformations of the tissues. One key step on this way is the gastrulation, which corresponds to the geometric separation of tissues with different genetic fate.

In the Drosophila embryo, this process starts by a single layer of cells (an epithelium) forming of a longitudinal fold which deepens and closes before it seals at the outer surface. Through mechanical modelling, we have shown that one of the mechanisms by which this fold forms is the buckling of the epithelium under the action of anisotropic internal stress. We now want to give a mechanical understanding of the process by which this fold deepens.

Through mechanical perturbations of the embryo, we show that the outer surface of the embryo engages in an adhesive interaction across the fold. The objective of this Master's project is to perform numerical simulations of the dynamics of folding and self-adhesion. The simulations will be based on an existing python environment allowing to simulate the mechanical behaviour of viscoelastic structures and the dynamics of adhesion.