Preparation of monodisperse calcium alginate microcapsules via internal gelation in microfluidic-generated double emulsions

• Published in: Journal of colloid and interface science 2013-08, Vol.404, p.85-90
• Main Authors: Liu, Li, Wu, Fang, Ju, Xiao-Jie, Xie, Rui, Wang, Wei, Niu, Catherine Hui, Chu, Liang-Yin
• Format: Article
• Language: English
• Subjects: Alginates - chemistry; Animals; bovine serum albumin; calcium; Calcium alginate; Calcium carbonate; Calcium carbonate nanoparticles; Capsules; Carriers; Carriers, Drug; Cattle; Chemistry; Colloidal state and disperse state; crosslinking; Double emulsions; Drugs; emulsifying; Emulsions; Emulsions. Microemulsions. Foams; Exact sciences and technology; Gelation; General and physical chemistry; Generators; Glucuronic Acid - chemistry; Hexuronic Acids - chemistry; Immobilized Proteins - chemistry; Indexing in process; Internal gelation; ions; Microcapsules; Microfluidic Analytical Techniques; Microfluidic emulsification; nanoparticles; nutrients; Physical and chemical studies. Granulometry. Electrokinetic phenomena; polymers; Serum Albumin, Bovine - chemistry; sodium alginate
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2013.04.044

[Display omitted] •Monodisperse hollow and core–shell calcium alginate microcapsules are prepared.•Microfluidic-generated monodisperse O/W/O emulsions are used as templates.•Internal gelation of the aqueous layer of O/W/O emulsions is achieved.•Gelation is initiated by UV exposure on CaCO3 particles and photoacid generator.•Protein can be encapsulated into the microcapsules after the capsule preparation. Monodisperse hollow and core–shell calcium alginate microcapsules are successfully prepared via internal gelation in microfluidic-generated double emulsions. Microfluidic emulsification is introduced to generate monodisperse oil-in-water-in-oil (O/W/O) double emulsion templates, which contain Na-alginate, CaCO3 nanoparticles, and photoacid generator in the middle aqueous phase, for synthesizing Ca-alginate microcapsules. The internal gelation of the aqueous middle layer of O/W/O double emulsions is induced by crosslinking alginate polymers with Ca2+ ions that are released from CaCO3 nanoparticles upon UV exposure of the photoacid generator. The as-prepared hollow and core–shell calcium alginate microcapsules are highly monodisperse and spherical in water. Model proteins Bovine serum albumin (BSA) molecules can be encapsulated into the Ca-alginate microcapsules after the capsule preparation, which demonstrates an alternative route for loading active drugs or chemicals into carriers to avoid the inactivation during the carrier preparation. The proposed technique in this study provides an efficient approach for synthesis of monodisperse hollow or core–shell calcium alginate microcapsules with large cavity or encapsulated lipophilic drugs, chemicals, and nutrients.