Pattern formation via cell–cell adhesion and contact inhibition of locomotion in active matter

Cell wetting and dewetting in soft substrates present a collection of non-cohesive and cohesive patterns. Prediction of this wide diversity is of critical importance in order to design experiments with polar active matter under confinement. Although in vivo, cells and the extracellular matrix (ECM) are enfolded by flexible substrates, at experimental realizations, hard boundaries are frequently employed. Here, the elastic forces exerted by the cells and the ECM—between a deformable layer and a solid substrate—allow to recast a continuum model that takes account of heterogeneous exchanges such as cell–substrate adhesion and averaged repolarization due to contact inhibition of locomotion (CIL). Theoretical results show that cell aggregation is enforced as increasing cell–cell adhesion and decreasing CIL strength and exhibit different phases from gaseous states to polar liquids and 3D clusters, in agreement with recent reports. Cell diffusion grows as cell rigidity increases, and reduction of ECM stiffness eases cell aggregation and cluster formation. The findings of this work provide the mechanisms that drive and resist active unstable states and can be used as a predictability tool in cell clustering and cell migration experiments.