Softness, anomalous dynamics, and fractal-like energy landscape in model cell tissues

TL;DR

This paper investigates the unique slow and anomalous relaxation dynamics of epithelial cell tissues, revealing that a fractal-like energy landscape and cell stiffness influence their glassy behavior and diffusion properties.

Contribution

It demonstrates that the anomalous dynamics in epithelial tissues arise from a fractal-like energy landscape and shows how cell stiffness modulates this behavior.

Findings

Epithelial tissues exhibit a fractal-like energy landscape affecting their dynamics.

Stiffer cells lead to conventional glassy relaxation, unlike softer cells.

Anomalous diffusion is linked to particles diffusing along specific phase space directions.

Abstract

Epithelial cell tissues have a slow relaxation dynamics resembling that of supercooled liquids. Yet, they also have distinguishing features. These include an extended short-time sub-diffusive transient, as observed in some experiments and recent studies of model systems, and a sub-Arrhenius dependence of the relaxation time on temperature, as reported in numerical studies. Here we demonstrate that the anomalous glassy dynamics of epithelial tissues originates from the emergence of a fractal-like energy landscape, particles becoming virtually free to diffuse in specific phase space directions up to a small distance. Furthermore, we clarify that the stiffness of the cells tunes this anomalous behaviour, tissues of stiff cells having conventional glassy relaxation dynamics.