Combining Hard Shell with Soft Core to Enhance Enzyme Activity and Resist External Disturbances.

Immobilizing enzymes onto solid supports having enhanced catalytic activity and resistance to harsh external conditions is considered as a promising and critical method of broadening enzymatic applications in biosensing, biocatalysis, and biomedical devices; however, it is considerably hampered by limited strategies. Here, a core-shell strategy involving a soft-core hexahistidine metal assembly (HmA) is innovatively developed and characterized with encapsulated enzymes (catalase (CAT), horseradish peroxidase, glucose oxidase (GOx), and cascade enzymes (CAT+GOx)) and hard porous shells (zeolitic imidazolate framework (ZIF), ZIF-8, ZIF-67, ZIF-90, calcium carbonate, and hydroxyapatite). The enzyme-friendly environment provided by the embedded HmA proves beneficial for enhanced catalytic activity, which is particularly effective in preserving fragile enzymes that will have been deactivated without the HmA core during the mineralization of porous shells. The enzyme encapsulated within a core-shell particle exhibits noteworthy resilience against harsh external conditions, including heat, organic solvents, and proteinase K. Additionally, no significant alteration in the catalytic behavior of the enzyme is observed after multiple cycles of usage. This study offers a novel approach for immobilizing enzymes and rendering them resistant to harsh external conditions, with potential applications in diverse fields, including biocatalysis, bioremediation, and biomedical engineering.