Monodisperse hybrid microcapsules with an ultrathin shell of submicron thickness for rapid enzyme reactions

In this study, we report a facile approach for the fabrication of monodisperse hybrid alginate/protamine/silica (APSi) microcapsules with an ultrathin shell of submicron thickness as enzyme encapsulation systems for rapid enzymatic reactions. Monodisperse water-in-oil (W/O) emulsions, which have been generated in microfluidics, are used as templates for preparing APSi microcapsules via internal/external gelation and biosilicification. The microcapsules allow highly-efficient encapsulation of model actives bovine serum albumin (∼99%) during the fabrication process. The hybrid shell with an ultrathin thickness of ∼420 nm provides fast mass transfer for the encapsulated model enzyme laccase to undergo rapid reaction. Moreover, this rigid hybrid shell also endows the encapsulated laccase with excellent reusability and storage stability. These ultrathin-shelled APSi microcapsules show great potential as efficient encapsulation systems for enzymes and biomolecules for their rapid reactions, and as delivery systems for actives in biomedical applications.