Collective effects in cellular structure formation mediated by compliant environments

Compliant environments can mediate interactions between mechanically active cells like fibroblasts. Starting with a phenomenological model for the behaviour of single cells, we use Monte Carlo simulations to predict non-trivial structure formation for cell communities on soft elastic substrates as a function of elastic moduli, cell density, noise and cell position geometry. We find that over a wide range of parameters, cells form short and uncorrelated strings, which screen the elastic interactions and thus allow for a macroscopically isotropic structure. At high cell density and small Poisson ratio, however, spontaneous polarization occurs, leading to strongly anisotropic macroscopic properties. At high cell density and Poisson ratio larger than 0.32, macroscopically isotropic order is reestablished, because local order changes from string-like to ring-like. Similar results are found in three dimensions. Our results suggest that in regard to elastic effects, healthy tissue usually is in a macroscopically disordered ∗Present address: Department of Bioengineering, Center for Synthetic Biology, University of California, Berkeley, CA 94720-3224, USA