Collective migration of epithelial monolayers

Recent wound healing assays using monoloayers of epithelial cells have observed highly correlated, complex cell motions that persist well beyond the wound border. Here, I use the gross dynamical behavior of a single crawling cell with a simple model for cell-cell interactions to explain the migratory dynamics and long-range correlations that occurs in epithelial monolayers. Three reasonable physical processes are necessary to produce the complex patterns that are observed: (1) Cells exert a dipole stress on their environement and on surrounding cells; (2) cells are polarized and there is a preference for neighboring cells to be polarized in the same direction; and (3) cell-cell adhesion acts as a viscous shear. This model reproduces the experimentally observed velocity correlation length and suggests new experiments that can be done to test the model.