Rheology and active dynamics of epithelial tissues

Epithelial tissues play a crucial role during embryonic development and in adult organisms, forming essential physiological barriers within the body. These tissues frequently undergo and even instigate significant deformations while maintaining mechanical integrity. This presentation explores the dynamics of epithelial tissues under a range of strains and strain rates with an emphasis on modelling strategies. Experimental investigations of in-vitro epithelial monolayers of MDCK cells reveal that these materials exhibit contractile behaviours, leading to active tensioning and spontaneous curling at free edges. We will analyse how the initiation of rupture results from the interaction between the material's non-linear rheology and the collective dynamics of linker populations at junctions. Epithelial tissues also evolve through cell rearrangements, particularly in embryonic tissues, which experience dramatic and permanent shape changes during development. The rate of these processes is influenced by the tissues' ability to remodel and dissipate stress in response to extrinsic (passive) and intrinsic (active) force generation. Through a modelling approach, we will investigate the interplay between tissue rheology, intrinsic force generation at the cellular level, boundary conditions, and the rates of the resulting morphogenetic processes.