Fig. 3: Physics of cell aggregation.

Simulations of cellular aggregation of macrophages (green / light) and proliferative cancer cells (purple or blue/dark) at the bottom of a well (orange surface). a Cells injected at the top of the well fall to the bottom with a rather weak Archimedean force just after the onset of the simulations and experiments¹⁰⁹. b After 60 h, aggregates have formed and coalesced into bigger aggregates. The process will ultimately lead to a single aggregate, with ejection of most of the macrophages. The simulations, realised with a particle-based model, incorporate cell-cell interactions, adhesion, friction with the liquid bath, cells, and substrate, cell proliferation, and nutrient diffusion. (Simulation images provided by Joseph Ackermann.)