(137a) Complex Coacervate Microemulsions

This presentation will discuss our progress in creating stable membraneless water-water emulsions comprising complex coacervate microdroplets. Complex coacervation is a liquid-liquid phase separation phenomenon driven by the electrostatic association of oppositely charged multivalent macromolecules in water, creating coacervate microdroplets enriched with charged moieties. These aqueous membraneless microdroplets possess numerous attributes desired in colloidal reactors and protocell models. However, the membraneless coacervate-water interface that facilitates many of the bio(techno)logical functions of the coacervate microdroplets also promotes their coalescence, resulting in rapid coarsening and sedimentation. We will discuss our recently discovered strategy to stabilize complex coacervate microdroplets without introducing membranous sheaths around the droplets by utilizing the assembly of anionic comb polyelectrolytes at the water(coacervate)-water interface. We will demonstrate the tunability of microdroplet size, its months-long stability, and its ability to withstand high ionic strength environments. Selective sequestration of charged (bio)molecules (proteins and enzymes) into the crowded environments of stabilized coacervate microdroplets will be argued to affect a significant (up to 10-fold) and sustained acceleration of enzyme-mediated bioreactions. Aided by the low cost of the constituent polymers and the simplicity of the formulations, we will argue that the stabilized coacervate emulsions serve as efficient enzyme-encapsulants in economical, large-scale flow bioreactors.