# Dense active matter model of motion patterns in confluent cell monolayers

## TL;DR

This paper demonstrates that dense active matter physics can explain the complex motion patterns in confluent cell monolayers, combining analytical models, simulations, and experiments to match observed velocity correlations.

## Contribution

It introduces a unified active matter framework to describe cell sheet dynamics, integrating continuum elasticity, normal modes, and agent-based models with experimental validation.

## Key findings

- Analytical model accurately predicts velocity correlations.
- Simulations match experimental data over long timescales.
- Persistent uncoordinated motility drives swirl-like correlations.

## Abstract

Epithelial cell monolayers show remarkable displacement and velocity correlations over distances of ten or more cell sizes that are reminiscent of supercooled liquids and active nematics. We show that many observed features can be described within the framework of dense active matter, and argue that persistent uncoordinated cell motility coupled to the collective elastic modes of the cell sheet is sufficient to produce swirl-like correlations. We obtain this result using both continuum active linear elasticity and a normal modes formalism, and validate analytical predictions with numerical simulations of two agent-based cell models, soft elastic particles and the self-propelled Voronoi model together with in-vitro experiments of confluent corneal epithelial cell sheets. Simulations and normal mode analysis perfectly match when tissue-level reorganisation occurs on times longer than the persistence time of cell motility. Our analytical model quantitatively matches measured velocity correlation functions over more than a decade with a single fitting parameter.