Improving the realism of the cellular Potts model in simulations of biological cells

Because the extended or cellular large-Q Potts model (CPM) captures effectively the global features of tissue rearrangement experiments, including cell sorting and tissue engulfment, it has become a common technique for cell level simulation of tissues. However, it omits three key elements of real cells, their fixed membrane area, their attractive binding and the dissipation of making and breaking membrane contacts. In this paper, we modify the Hamiltonian to use negative surface energies, constrained surface area and a spin flip energy threshold to improve the correspondence to reality. We find that the new model correctly predicts several dynamical behaviors of cells which the original CPM does not, including the hierarchy of diffusion constants.