Active phase separation in bacteria-polymer mixtures

Membraneless liquid condensates formed via liquid-liquid phase separation (LLPS) play a pivotal role in cell biology and are of great potential in biomedical engineering. While liquid condensates are often studied in the context of interactions between passive components, it is increasingly recognized that active matter inclusions, such as molecular motors and catalytic enzymes in cells and synthetic self-propelled particles, play important roles in the dynamics of liquid condensate formation, transport, and interaction. Here we developed a unique active phase separation system to study the nonequilibrium effect of active matter inclusions on LLPS dynamics. We found that the presence of bacterial active matter modifies the LLPS process via active transport. Besides, the system spontaneously develops membraneless active droplets displaying an array of intriguing non-equilibrium phenomena. The active phase separation system with active droplet formation offers a platform for investigating non-equilibrium LLPS in living cells or biomedical engineering applications.