Hybrid hydrogel reactor with metal–organic framework for biomimetic cascade catalysis

It has always been a goal for immobilized enzymes to work under their native conformational states while possessing robust stabilities in harsh environments. Hydrogel is a promising enzyme matrix because of its cell-like microenvironment and porous internal structure to preserve the conformations of enzymes, maximizing catalytic efficiency. However, the challenges in low chemical tolerance and poor mechanical strength remained. Herein, a unique organic/inorganic hybrid hydrogel system was fabricated through the interfacial mineralization of metal–organic frameworks (MOFs) on hydrogel microsphere for processing biomimetic cascade reaction. The combination of hydrogel and MOFs layer is synergistic. The porous hydrogel network offers a biocompatible space for encapsulated enzymes to eliminate their undesirable restriction and chemical interactions with hosts, allowing the enzymes to work under native states for benefiting high activity, while the inorganic MOFs layer protects the enzymes from harsh environments to endow the hybrid reactor with robust stabilities. Attractively, a high enzyme tolerance against polar organic solvents was approached in the hybrid reactor. In addition, by the spatial arrangement of different enzymes in inner hydrogel and outer MOFs layer, the hybrid reactor can also function as a multi-compartmental structure for performing incompatible enzyme reactions to give distinguished reaction fluxes and product outputs, as occurred in natural cells.