Linear Viscoelastic Properties of the Vertex Model for Epithelial Tissues

TL;DR

This study systematically analyzes the viscoelastic properties of the vertex model for epithelial tissues across the full dynamic range, revealing how mechanical responses can be tuned between solid-like and fluid-like states.

Contribution

It provides a comprehensive analysis of the vertex model's rheological behavior under various conditions, including the effects of pre-deformation on phase transition.

Findings

Fluid and solid phases follow standard viscoelastic models

Mechanical response can be tuned by pre-deformation

Full dynamic range behavior characterized

Abstract

Epithelial tissues act as barriers and, therefore, must repair themselves, respond to environmental changes and grow without compromising their integrity. Consequently, they exhibit complex viscoelastic rheological behavior where constituent cells actively tune their mechanical properties to change the overall response of the tissue, e.g., from solid-like to fluid-like. Mesoscopic mechanical properties of epithelia are commonly modeled with the vertex model. While previous studies have predominantly focused on the rheological properties of the vertex model at long time scales, we systematically studied the full dynamic range by applying small oscillatory shear and bulk deformations in both solid-like and fluid-like phases for regular hexagonal and disordered cell configurations. We found that the shear and bulk responses in the fluid and solid phases can be described by standard spring-dashpot viscoelastic models. Furthermore, the solid-fluid transition can be tuned by applying pre-deformation to the system. Our study provides insights into the mechanisms by which epithelia can regulate their rich rheological behavior.