A density-independent glass transition in biological tissues

TL;DR

This paper reveals a new rigidity transition in confluent biological tissues, governed by cellular properties rather than density, explaining liquid-to-solid transitions in tissue monolayers.

Contribution

It introduces a novel density-independent glass transition in confluent tissues using the vertex model, linking cellular parameters to tissue rigidity.

Findings

Rigidity onset depends on cell adhesion and tension parameters.

Transition occurs at constant density, unlike traditional density-driven glass transitions.

Provides testable predictions for tissue mechanics based on cell properties.

Abstract

Cell migration is important in many biological processes, including embryonic development, cancer metastasis, and wound healing. In these tissues, a cell's motion is often strongly constrained by its neighbors, leading to glassy dynamics. While self-propelled particle models exhibit a density-driven glass transition, this does not explain liquid-to-solid transitions in confluent tissues, where there are no gaps between cells and therefore the density is constant. Here we demonstrate the existence of a new type of rigidity transition that occurs in the well-studied vertex model for confluent tissue monolayers at constant density. We find the onset of rigidity is governed by a model parameter that encodes single-cell properties such as cell-cell adhesion and cortical tension, providing an explanation for a liquid-to-solid transitions in confluent tissues and making testable predictions about how these transitions differ from those in particulate matter.