摘要Encapsulation of water-soluble cargoes in millimeter-sized capsules has enabled major advances in various fields,including pharmaceuticals,food,cosmetics,packaging,and materials.However,because of the lack of fabrication precision,low cargo retention,suboptimal mechanical properties,and difficulty in preventing water evaporation,this technique is more challeng-ing than microencapsulation techniques.In this study,we developed a surfactant-free and organic solvent-free water-in-oil-in-air emulsification approach for synthesizing double-layered"milli-capsules"for the precise encapsulation,enhanced reten-tion,and force-triggered burst release of water-soluble bioactive cargoes.In particular,we synthesized milli-capsules with a first shell of poly(ethylene glycol dimethacrylate)for the efficient encapsulation of bioactive cargoes and a second shell of beeswax to prolong the retention of the entrapped bioactive compounds.Unlike traditional milli-capsules,which exhibit poor shape uniformity and mechanical stability,we introduced metallic ions to stabilize the interfacial tension and employed con-stant rotation to balance the gravity,buoyancy,inertial,and viscous forces imposed on the droplets,resulting in uniform and rigid milli-capsules with narrow rupture forces.Furthermore,additional hydrophobic beeswax coating prevented water vola-tilization and substantially prolonged the shelf life of the encapsulated compounds from a few days to a few months while maintaining their bioactivities.The proposed milli-capsule system addresses the challenge of precise fabrication of large car-riers for water-soluble cargoes,representing a significant step toward the long-term storage and controlled release of bioac-tive cargoes for various industrial applications.