Marino Arroyo (Polytechnic University of Catalonia, Barcelona, Espagne). Fracture mechanics of epithelial cell monolayers.

Epithelial monolayers are extremely simple tissues. They are sheets of cells attached to a matrix, which delimit boundaries in our body. Yet, they perform vital functions while being subject to extreme deformations. Thanks to a contractile machinery and to adhesions mediated by binder molecules, epithelia combine mechanical resilience with an ability to remodel into 3D shapes or to self-heal. In this talk, I will discuss the mechanical principles behind the fracture behavior and the resilience of these living materials. Based on recent experiments and on simple mechanical models, I will discuss the role of matrix poroelasticity, of the tension in the cell surface, and of the competition between breaking molecular bonds or dragging them to create new fracture surface. These principles governing the mechanics of epithelia may provide new ideas for artificial materials.