In addition to cell crawling, cell pulsation is also prevalent in the morphogenesis and pattern formation of epithelial tissues. Exploring the structure and dynamics of pulsating cell tissue can help revealing the formation mechanism of these life processes. Recently, a theoretical work appearing in Proc. Natl. Acad. Sci. U.S.A reports how pulsating activity induces fluidization, hidden topological defects and anomalous density fluctuations in 2D cell tissues. More explicitly, the work finds that random cell pulsation fluidizes solid epithelial tissue into a hyperuniform fluid state, while pulsation synchronization inhibits the fluidity and causes a reverse solidification. This solidification is dominated by hidden topological defects of cell pulsation and is characterized by strong density fluctuations and dynamic heterogeneity. In addition, the magnitude and length scale of density fluctuations diverge with the pulsating period, resulting in a giant density fluctuation state during pulsation synchronous. Finally, the authors show that the hyperuniform fluid state and the giant fluctuation state of cell tissue can be unified into a fluctuating hydrodynamic theory. This work reveals the key role of hidden topological defects in the structure and dynamics of pulsating cell tissues, and helps guide experiments to discover the hyperuniform fluid state of cell tissues. This work is from Prof. Yu-Qiang Ma group in school of physics in NJU.

Publication link: https://www.pnas.org/doi/10.1073/pnas.2421518122