Biomimetic emulsions reveal the effect of homeostatic pressure on cell-cell adhesion

TL;DR

This study uses biomimetic emulsion droplets to investigate how homeostatic pressure influences cell-cell adhesion, revealing a threshold force for adhesion and pressure-dependent strengthening, independent of active cellular processes.

Contribution

It introduces a novel biomimetic emulsion system to isolate and analyze the mechanical effects of pressure on cell adhesion, providing new insights into physical adhesion mechanisms.

Findings

A threshold compression force is needed to establish adhesion.

Adhesion strength increases with applied pressure.

Theoretical model predicts binder concentrations similar to real cells.

Abstract

Cell-cell contacts in tissues are continuously subject to mechanical forces due to homeostatic pressure and active cytoskeleton dynamics. While much is known about the molecular pathways of adhesion, the role of mechanics is less well understood. To isolate the role of pressure we present a dense packing of functionalized emulsion droplets in which surface interactions are tuned to mimic those of real cells. By visualizing the microstructure in 3D we find that a threshold compression force is necessary to overcome electrostatic repulsion and surface elasticity and establish protein-mediated adhesion. Varying the droplet interaction potential maps out a phase diagram for adhesion as a function of force and salt concentration. Remarkably, fitting the data with our theoretical model predicts binder concentrations in the adhesion areas that are similar to those found in real cells. Moreover, we quantify the adhesion size dependence on the applied force and thus reveal adhesion strengthening with increasing homeostatic pressure even in the absence of active cellular processes. This biomimetic approach reveals the physical origin of pressure-sensitive adhesion and its strength across cell-cell junctions.