Contractile stresses in cohesive cell layers on finite-thickness substrates

TL;DR

This study models how substrate thickness and stiffness influence traction forces in cohesive cell layers, providing a unified framework that predicts stress distribution and force generation based on physical parameters.

Contribution

It introduces a minimal continuum active elastic model that captures the effects of substrate properties on cellular traction forces, bridging thin and thick substrate regimes.

Findings

Derived a simple expression for stress variation length scale.

Predicted how traction forces depend on substrate stiffness and thickness.

Provides experimentally testable predictions for cell-substrate interactions.

Abstract

Using a minimal model of cells or cohesive cell layers as continuum active elastic media, we examine the effect of substrate thickness and stiffness on traction forces exerted by strongly adhering cells. We obtain a simple expression for the length scale controlling the spatial variation of stresses in terms of cell and substrate parameters that describes the crossover between the thin and thick substrate limits. Our model is an important step towards a unified theoretical description of the dependence of traction forces on cell or colony size, acto-myosin contractility, substrate depth and stiffness, and strength of focal adhesions, and makes experimentally testable predictions.