Microgel-engineered temperature-responsive microcapsules at liquid interfaces for sequential biocatalytic reactions

Abstract

Microgels, with their adjustable deformability and responsiveness, offer a promising alternative to prepare microcompartments via template-directed assembly onto emulsion droplets. Herein, we introduce a robust and reproducible strategy to synthesize responsive microgel poly(N-isopropylacrylamide-co-serine) (PNSER)-stabilized Pickering emulsions (both water-in-oil (W/O) and oil-in-water (O/W)) to design tunable vesicles (called microgelsomes) that could encapsulate hydrophobic and hydrophilic molecules. Unlike previous approaches that typically support only one emulsion type, our system uniquely accommodates both, offering a versatile platform for encapsulating a broad spectrum of active biomolecules within a single framework. The system was validated by applying it to two catalytic systems: antioxidation activity of lipophilic vitamin E and a bienzymatic cascade reaction involving laccase and transaminase to catalyze the stereoselective amination of racemic alcohols, yielding chiral amines, important for the synthesis of pharmaceutical drugs. We addressed the challenge of using two different pH requirements for the enzymes by conducting the cascade in a one-pot reaction at a single pH, thereby enhancing the efficiency and simplicity of the process. Impressively, the one-pot bienzymatic cascade produced 95–98% conversion, 2-fold higher than that of their free counterpart (43–50%) and comparable to that of the two-step sequential reaction performed at their respective optimal pH values.