Polymeric Janus Colloids Enable a New Paradigm of Spatially Confined Enzymes in Pickering Interfacial Catalysis

Precise spatial confinement of enzymes at oil-water interfaces offers an elegant strategy to enhance biphasic catalysis yet achieving robust and recyclable interfacial assemblies remains challenging. Here, we introduce an amphiphilic polymeric Janus particle platform that enables lipases to preferentially localize at interfaces, thereby achieving efficient Pickering interfacial catalysis (PIC). Crosslinked poly(hydroxypropyl methacrylate) colloids bearing surface carboxylic acid groups were synthesized via RAFT-mediated heterogeneous copolymerization and further transformed into snowman-shaped Janus particles through seeded emulsion polymerization. The resulting amphiphilic Janus colloids possess distinct hydrophilic-hydrophobic domains that facilitate both enzyme anchoring and emulsion stabilization. Candida rugosa lipase (CRL) immobilized on these particles exhibited strong interfacial activity, achieving enhanced catalytic efficiency, thermal stability, and recyclability compared to free CRL. The present work suggests that enzyme immobilization on Janus colloids is a promising approach to advance next-generation PIC.