Biological & Soft Matter Seminar: Dynamics and transport in active biomolecular condensates

Abstract:

Biomolecular condensates play key roles in living cells by enabling membrane-free compartmentalization. Cells routinely utilize energy-consuming processes to regulate biocondensates. In this talk, I will discuss how active chemical reactions, interconverting molecules between phase-separating and inert forms, can give rise to nontrivial biocondensate dynamics. 

First, I will present a theory pinpointing how activity can accelerate condensate coarsening. Despite activity, we find that mass conservation limits droplet volume growth to being linear in time, as in the passive Lifshitz-Slyozov theory. However, if reactions are restricted to occur only outside droplets, the rate of Ostwald ripening can be increased by an arbitrarily large factor. 

Second, I will show that active droplets can generate transport. Motivated by self-propelled matter, we ask what minimal ingredients are required for a passive colloid suspended in an otherwise isotropic fluid to move? I will demonstrate that coupling to nonequilibrium phase separation is sufficient to produce spontaneous symmetry breaking and sustained propulsion.

A joint work with Ned Wingreen (Princeton).