Abstract

Deformation of single cells in biological tissues plays a strategic role in key processes such as stress propagation, cardiac arrhytmias and wound healing. The size and shape of a cell depends on its internal cytoskeletal activity and nearest-neighbors interactions in a dense environment. Size synchronization and contraction waves emerge as collective behavior typical of non-equilibrium systems. We introduce pulsating active matter (PAM) as a physical framework to model these scenarios and provide the minimal ingredients to observe the non-equilibrium phases mentioned. Activity in PAM does not enter as a classical self-propulsion mechanism but rather as a non-equilibrium dynamics of the degrees of freedom controlling the cells’ shape. These assumptions lead to collective dynamics, which can be analysed through a coarse-grained hydrodynamic approach. We elucidate the role of density and size fluctuations and the general mechanisms yielding the transitions described. PAM provides then a framework to tackle emerging challenges in the collective behavior of deformable units. Co-Authors: Étienne Fodor, Yiwei Zhang, Luca Casagrande References: Y. Zhang and É. Fodor, Pulsating Active Matter, Phys. Rev. Lett. 131, 238302 ; A. Manacorda and É. Fodor, Pulsating with Discrete Symmetry, arXiv:2310.14370