Competition between activity and shear in biological tissues: yielding, shear thinning and discontinuous shear thickening.

Biological tissues demonstrate mechanical integrity and solid-like behaviour on short time scales, while exhibiting cellular rearrangements and liquid-like flow over longer time scales. Such complex jamming/unjamming behaviour underpins many important processes, including wound healing, cancer development and morphogenesis. In this work, we study numerically the yielding behaviour of biological tissues using a minimal vertex-based model, in which a 2D layer of confluent cells is represented by a tiling of polygons, defined by the positions of the vertices [1]. When a tissue is in the vicinity of the solid-fluid transition, we find that internal active forces compete with an externally applied shear to produce a host of distinct rheological behaviours, including yielding, shear thinning, continuous shear thickening, and discontinuous shear thickening



[1] Mitchel, Jennifer A., et al. In primary airway epithelial cells, the unjamming transition is distinct from the epithelial-to-mesenchymal transition. Nature communications 11.1 (2020): 1-14.