Chemically Active Liquid Bridges Generate Repulsive Forces

Droplets help organize cells by compartmentalizing biomolecules and by mediating mechanical interactions. When bridging two structures, such droplets generate capillary forces, which depend on surface properties and distance. While the forces exerted by passive liquid bridges are well understood, the role of active chemical reactions, which are often present in biological droplets, remains unclear. To elucidate this case, we study a single liquid bridge with continuous chemical turnover. These reactions control the bridge radius and lead to purely repulsive forces-contrasting with the typically attractive forces in passive systems. Our results reveal how chemical activity can fundamentally alter forces generated by liquid bridges, which could be exploited by cells.