Phase transitions and collective motion in cellular assemblies are central to a wide range of biological processes, including morphogenesis and wound healing. In particular, the transition from a fluid-like to a solid-like state, often described as jamming, has been compared to a glass transition and traditionally associated with increasing cell density [1]. However, more recent evidence indicates that other factors, such as cell–cell and cell–substrate adhesion, may play a more dominant role [2].
In this study, we critically assess the universality of jamming behavior across monolayers formed by various epithelial and fibroblast cell lines. By combining real and reciprocal space analysis, we observe that although all systems display an initial ballistic-like motility, their dynamical evolution toward arrest differs markedly. Some monolayers gradually slow down while maintaining the same type of motion, whereas others undergo a clear transition from ballistic to diffusive behavior. Importantly, these differences are not limited to distinctions between epithelial and mesenchymal cell types but also occur among cell lines of the same type. This demonstrates that jamming is not a universal process governed by a single set of physical principles.
We further show that changes in motility often coincide with the emergence of spatial order within the tissue, as evidenced by variations in the static structure factor. Differential Dynamic Microscopy proves particularly effective in detecting these transitions, providing robust access to multiscale dynamics even under conditions of high cell density or low image contrast. Taken together, our findings challenge the concept of universality in the jamming of cellular monolayers and highlight the need for cell-type-specific frameworks to understand collective arrest in living tissues.
References
[1] T. Angelini, E. Hannezo, X. Trepat, M. Marquez, J. Fredberg, D. Weitz, Proc. Natl. Acad. Sci. U.S.A., 108, 4714-4719 (2011)
[2] S. Garcia, E. Hannezo, J. Elgeti, J. Joanny, P. Silberzan, N. Gov, Proc. Natl. Acad. Sci. U.S.A., 112, 15314-15319 (2015)