Abstract

Cells in tissues consume fuel to sustain periodic mechanical deformation [1]. The combination of individual deformation and local interactions yields contraction waves, propagating throughout tissues with only negligible cell displacement [2]. We consider a model of dense repulsive particles whose activity drives periodic change in size of each individual [3]. It reveals that, in dense environments, pulsation of synchronised particles is a generic route to contraction waves. The competition between repulsion and synchronisation triggers an instability which promotes a wealth of dynamical patterns, ranging from spiral waves to defect turbulence. We identify the mechanisms underlying the emergence of patterns, and characterize the corresponding transitions. We derive the hydrodynamics of our model, and propose an analogy with that of reaction-diffusion systems. References: [1] S. Zehnder, M. Suaris, M. Bellaire, and T. Angelini. (2015) Cell volume fluctuations in MDCK monolayers, Biophys. J. [2] X. Serra-Picamal, V. Conte, R. Vincent, E. Anon, D. T. Tambe, E. Bazellieres, J. P. Butler, J. J. Fredberg, and X. Trepat. (2012) Mechanical waves during tissue expansion, Nat. Phys. [3] Y. Zhang and É. Fodor. (2022) Pulsating active matter, arXiv:2208.06831.