Elasticity of supported epithelia based on interfacial surface tensions

The shape and function of epithelial tissues in animal organisms are closely interconnected and it remains somewhat a mystery how a simple structure like an early embryo, can evolve into a complex adult organism where all parts work coherently to carry out the essential functions needed to sustain life. We address this mystery from the perspective of mechanics and study epithelia using computational and analytical methods, which describe the mechanics at the whole-tissue scale with a single-cell resolution. I will present an elasticity theory of epithelial monolayers, supported by the basement membrane and the stroma. This theory is derived from a description of the mechanics at a single-cell level, following a century-old analogy between cells and liquid droplets. We find that epithelia made of droplet-like cells may become contractile and either wrinkle or buckle out of plane. The specific droplet-like cell mechanics lead to unusual scaling of some key physical parameters with layer's thickness and–in contrast to "ordinary" elastic layers–our wrinkled epithelia may undergo phase inversion of the groove-to-crest thickness modulation.