Nonlinear and Nonlocal Elasticity in Coarse-Grained Differential-Tension Models of Epithelia

TL;DR

This paper develops a continuum mechanics model for epithelial tissues based on differential tension, revealing nonlinear and nonlocal elastic behaviors that explain tissue deformation and buckling under compression.

Contribution

It introduces a continuum theory derived from cell-level differential tension models, elucidating nonlinear and nonlocal elastic effects in epithelial tissues.

Findings

Reveals nonlinear elastic behavior in epithelial models.

Shows nonlocal effects influence tissue buckling.

Connects cell-level tension differences to macroscopic mechanics.

Abstract

The shapes of epithelial tissues result from a complex interplay of contractile forces in the cytoskeleta of the cells in the tissue, and adhesion forces between them. A host of discrete, cell-based models describe these forces by assigning different surface tensions to the apical, basal, and lateral sides of the cells. These differential-tension models have been used to describe the deformations of epithelia in different living systems, but the underlying continuum mechanics at the scale of the epithelium are still unclear. Here, we derive a continuum theory for a simple differential-tension model of a two-dimensional epithelium and study the buckling of this epithelium under imposed compression. The analysis reveals how the cell-level properties encoded in the differential-tension model lead to linear, nonlinear as well as nonlocal elastic behavior at the continuum level.