Hole closure in sheets of active deformable particles

Holes created in sheets of epithelial cells provide an in vitro experimental system to gain insight into wound healing in biological tissues. Experimental studies have found that holes close as a result of collective cell motion that is influenced by cell shape, motility, and adhesion. We propose the deformable particle (DP) model to study the mechanics of hole closure in epithelial sheets, where the cells are modeled as individual deformable polygons with N_v vertices whose positions are determined by a shape-energy function with terms that control the cell area, perimeter, and curvature. To model the dynamics of hole closure, we include adhesive protrusions and collective contractile tensions for cells along the perimeter of the hole.  An important advantage of the DP model for describing hole closure is the ability for individual cells to take on a wide range of complex shapes.  We vary the cell adhesion, shape parameter, rate of protrusion, and contractile tension to determine how they affect collective cell motion and the rate of hole closure.