Effect of intercellular friction in active vertex and Voronoi models of cellular monolayers

While the role of intercellular adhesion through the energy functional has been previously examined in active vertex and Voronoi models, intercellular adhesion also gives rise to intercellular friction, whose effect has not yet been systematically explored. We add intercellular friction to the traditional vertex and Voronoi models and measure the glassy dynamics, such as alpha-relaxation time, with varying parameters, including the traditional parameters like dimensionless preferred perimeter and persistence time, as well as the new parameter controlling strength of intercellular friction. We find that the dependence of the alpha-relaxation time on the dimensionless preferred perimeter can be fitted to a Vogel–Fulcher–Tammann equation. The critical dimensionless preferred perimeter and prefactor increase when persistence time is decreased, promoting glassiness. However, the fragility index decreases. Introducing intercellular friction produces similar effects as decreasing persistence time. Additionally, the increase of the prefactor upon introducing friction is larger when persistence time is decreased, indicating that the effect of friction is stronger when persistence time is shorter.