Effective pressure in a dense cell monolayer and collective cell migration

A system of dividing and growing cells provides an intriguing example of active matter far from equilibrium. Living cells in a dense system are all in contact with each other. The common assumption is that such cells stop dividing due to a lack of space. Recent experimental observations have shown, however, that cells continue dividing for some time, even after a dense cell monolayer is formed. Effective pressure is introduced in order to model the experimentally observed phenomenon in which the average cell size dramatically decreases over time, and cell area distribution becomes narrower. For a non-uniform system, I will consider the cell shift due to the gradient of the effective pressure and examine its effect on the average cell area profiles. Then I will discuss collective cell migration where cells maintain contact with their neighbors. This migration can be described in terms of a novel front propagation phenomenon; the front speed and effective pressure profile are found both numerically and analytically.