Glassy Dynamics in a Simulated Cell Monolayer with Division and Death

Recent experiments have indicated that quasi two-dimensional epithelial tissues undergo a transition to a rigid state which shares many characteristics with traditional particulate glass. At the same time, numerical work has suggested that the presence of cell division and death in dense particle-based models for tissues will always destroy signatures of glassy dynamics such as caging. Can then glassy behavior be recovered in real tissues where cells commonly divide and die? We address this question with a vertex-type model of motile tissue modified to include a balanced rate of cell division and death. The division and death rate competes with the motility-driven rate of cell rearrangement to control the tissue dynamics. We show that glassy dynamics is recovered for slow division and death rates. Further quantifying the displacements coming from a single division or death event, we are able to accurately predict the crossover between motility-dominated and division/death-dominated rheology.