Incorporation of porous organic cages in the shell of organosilica network capsules for enzyme immobilization

Enzyme catalysis is widely used in industrial bioprocesses, but free enzymes often suffer from low stability, poor reusability, and limited mass transfer. Capsule encapsulation improves stability by providing a cell-mimetic confined microenvironment, while limited shell permeability often restricts mass transfer, reducing catalytic activity. In this work, the immobilized enzyme system (MDH@OSN-RCC2) was prepared by incorporating the porous organic cage RCC2 into an organosilica network (OSN) for the encapsulation of mannitol dehydrogenase (MDH). RCC2 integration adjusted the capsule’s pore structure. At 3 g L −1 RCC2, the specific surface area and total pore volume increased by 3.48-fold and 3.31-fold, the diffusion rate of fructose increased 6.84-fold, and the catalytic efficiency ( k cat / K m ) was 2.05-fold higher than MDH@OSN. The system retained 71.8 % of initial activity after 11 reuse cycles and performed stably over a broad temperature and pH range. This strategy was also applied for whole-cell immobilization that exhibited excellent operational stability and environmental tolerance. This study offers a design principle for durable biocatalysts in industrial and green biomanufacturing applications.