Incorporating mobile nanospheres in the lumen of hybrid microcapsules for enhanced enzymatic activity.

Physical encapsulation of enzymes in microcapsules, as a mild, controllable method, has been widely utilized for enzyme immobilization. However, this method often suffers from the big mass transfer resistance from the capsule lumen. In this study, a novel biocatalysis system with enhanced catalytic activity is constructed through coencapsulating enzymes and nanospheres in the lumen of protamine/silica hybrid microcapsules, which are synthesized through the synergy of biomimetic silicification and layer-by-layer (LbL) assembly. When utilized as the host for catalase (CAT) encapsulation, the hybrid microcapsules maintain high mechanical stability, high enzyme loading, and low enzyme leaching. Particularly, because of the existence of mobile nanospheres, the mass transfer resistance in the microcapsules is significantly reduced because of the vigorous agitation, thus acquiring an enhanced catalytic activity. Our strategy may also find applications in drug delivery and biosensor fields.