(23g) Substrate Surface Tension and Marangoni Effects Mediate Cell-Cell Coordination in Migration and Multicellular Assembly

Cell motion plays a critical role in many biological processes, including multicellular assembly and wound healing. It is still largely unclear through which mechanisms cells communicate with each other in coordinated motions during migration and assembly. We hypothesize that surface tension of the extracellular matrix conveys messages from cell to cell during collective processes. We find that cells can spread and migrate efficiently on viscous liquid silicone materials that have high surface tension. We observe that cells on these materials migrate through a highly collective, swarming-type motility with enhanced mutual spatiotemporal correlations compared to those on the substrates with lower ratios of surface tension to elastic modulus. Enhanced cell-cell correlation results from various mechanical interactions, including cell-matrix contractile forces and intermolecular attractive forces (surface tension) at the interface between extracellular materials and the aqueous cell culture solution. Marangoni flow is driven by surface tension gradients at the interface between two phases. In our case, extracellular materials and the aqueous cell culture solution have different surface tensions. Thus, we propose that the interface between these two phases undergoes convective shear motion driven by the gradient of surface tensions generated by cell contractility on the substrate surface. Together, our results suggest that cells on viscous substrates with relatively high surface tension coordinate their motions through the convective shear flow of the interface.