Transition of Polyelectrolyte Complexes from Solid-Liquid to Liquid-Liquid Systems through Enzymatic Degradation

We investigated the use of cellulase to convert precipitates from polyelectrolyte complexes into complex coacervates. We used two systems (carboxymethyl cellulose with poly(L-lysine) (pLK) and carboxymethyl cellulose with poly(diallyldimethylammonium chloride) (PDADMAC)) as our models to explore the use of enzymes to weaken the interactions between the oppositely charged polymers to move from solid precipitates to liquid coacervate droplets. Initially, both systems begin with liquid-solid phase separation with no change in morphology over time. With the addition of cellulase, we observe a shift from these precipitates through a transition to liquid droplets via brightfield microscopy. We mediate this transition through enzyme concentration, polymer concentration, and time. Through turbidity and microscopy, we see changes in the morphology and level of complexation, indirectly detailing the kinetics of each system. We further described these systems by employing the Lineweaver-Burke plot to estimate the characteristic concentration, K_M. We observed a more rapid transition from solid-liquid to liquid-liquid phase separation with our PADMAC system than with pLK. These systems and results begin the basis for a novel method of transitioning precipitate materials into liquid-liquid phase separated materials with the potential for molecule stabilization and release.