Hyperbranched Polymer-Cross-Linked Enzyme Aggregates for the Compartmentalized Coimmobilization of Enzymes and Metal Nanoparticles

The coimmobilization of enzymes and metal nanoparticles (MNPs) is an effective strategy for improving the efficiency of chemoenzymatic cascades. Cross-linked enzyme aggregates (CLEAs), as catalytic scaffolds, have been utilized as scaffolds for coimmobilization, leading to relatively high volumetric and space-time yields. However, it is still a challenge to achieve compartmentalization of enzymes and MNPs in CLEAs, likely due to the poor affinity between cross-linkers and MNPs. To overcome this shortcoming, here we have developed a void-adaptive cross-linking strategy for the preparation of hyperbranched polymer-cross-linked enzyme aggregates (HPCLEAs) that could be used as scaffolds for the immobilization of MNPs. Hyperbranched polymers were in situ-synthesized and could void-adaptively cross-link enzyme aggregates. They could also complex with metal precursors and then template the formation of MNPs via the in situ reduction of metal precursors, leading to the compartmentalization of several combinations of lipase and glucose oxidase (GOx) with MNPs, including Pd, Pt, Au, PdPt, AuPd, and AuPt. The physicochemical and catalytic properties of these chemoenzymatic catalysts were systematically studied to gain a deeper insight into structure-activity relationships. This strategy is promising for the development of more efficient chemoenzymatic cascades and can be extended for the compartmentalized coimmobilization of other enzymes and MNPs.