Can Surface Adhesion Drive Cell-rearrangement? Part I: Biological Cell-sorting

We explore the dynamical effects of surface adhesion on biological cell-sorting. We start with the simple idea that cell—cell adhesion is associated with an energy per unit area and define the total adhesion energy as a function of the cell configuration. We discuss whether deterministic cell motion, following the gradient of this position-dependent energy, can successfully explain cell-sorting in biology. We conclude: (i) Adhesion alone could be the source of cell movement. Internal cell activity is not necessary, although not excluded. (ii) For mixtures of two cell types, differential adhesion suffices to make clusters of the more cohesive cells coalesce and round. (iii) The presence of stable or metastable configurations, reached by relaxation of cell—cell adhesion energy, can explain why cell movement stops in biological experiments. (iv) Free boundaries, temperature and cell shapes affect cell-sorting. (v) Adhesion can also drive rearrangement in an homogeneous collection of cells.