Utilization of Polyelectrolyte Complex (PEC) Microdroplets as Bioreactors

Polyelectrolyte complex coacervate dispersions are a versatile platform for the realization of aqueous colloidal encapsulants and bioreactors. The membraneless microdroplets comprising these dispersions form by liquid-liquid phase separation and introduce a distinct and unstable water-water interface with external aqueous environments, eventually leading to their coalescence and resulting in macro phase separation. We have previously shown that comb polyelectrolytes (cPE) stabilize the coacervate microdroplets against coalescence, enabling the formulation of stable coacervate microemulsions. In this talk, we will demonstrate that these stabilized microdroplets possess unique properties as compared to unstable dispersions, including higher salt resistance, an expanded two-phase region, stable compartmentalization over longer periods of time, higher stability under diverse conditions (temperature, pH, ionic strength), and tunable small molecule diffusion across the coacervate-water interface. These improvements will be shown to allow co-encapsulation of multiple enzymes while minimizing the transport of intermediate products, leading to enhancement in the reaction kinetics of enzymatic cascades. Overall, these findings will serve as a bridge between existing knowledge and tailoring the design of microdroplets to expand their utilization as lipid-free artificial protocells and bioreactors.