Dynamics of cellular materials : from foams to biological tissues

par François GRANER, Matière et Systèmes Complexes, Université Paris Diderot – CNRS

Le MARDI 16 Décembre à 14h, salle des séminaires, bâtiment A4, 3e étage

Liquid foams are made of gas bubbles surrounded by water. They are model systems to understand complex cellular materials (made of cells tiling the space), which behave simultaneously as solids and liquids.

We have established tools to link the discrete description, at the bubble scale, with a continuous description, which encompasses the information useful at the global level. This enabled us to suggest a theoretical model able to predict how a foam flows in general geometries. It has been successfully tested against an experiment in a channel where a foam flows around various obstacles.

Such descriptive tools apply to a large class of disordered systems, irrespective of the underlying physics. They even apply to aggregates of living cells, despite their huge difference with bubbles. The approach has been used to investigate the development of living tissues in the fruit fly (drosophila). Movies of the fly back resolve all details of cell contours during the metamorphosis from fly larva to adult. Multi-scale analysis determines how individual cell changes (displacements, deformations, divisions) determine the tissue development.