Liquid-liquid phase separation and coarsening in an active fluid

Recent studies have revealed the existence of non-membrane bound organelles which form via liquid-liquid phase separation in cytoplasmic and nucleic cellular environments. These liquid-like bodies undergo a coalesce-based coarsening process which increases their average size over time. Nucleic organelle motion and coarsening rate have been well studied, however it is not clear how the out-of-equilibrium nature of the cell cytoplasm contributes to organelle coarsening. We investigate the impact of cytoplasmic flows on liquid-liquid phase separation by immersing phase separating DNA structures in microtubule-based active fluids. In my talk, I will show that active flows yield short-time superdiffusive motion and long-time diffusive motion, and that this motion accelerates droplet coarsening compared to a passive network. I will also show that the coarsening rate of actively mixed condensates monotonically increases with increasing activity. Together, these results could provide a better understanding how forces generated by the cytoskeleton impact the coarsening of membranless organelles.