Characterization of hydrophilic and hydrophobic core-shell microcapsules prepared using a range of antisolvent approaches

This study describes three straightforward approaches to leveraging gel network-restricted antisolvent precipitation techniques as a means of preparing hydrophilic hydrophobic core-shell microparticles. Briefly, hydrophilic polysaccharides (sodium alginate (ALG), κ-carrageenan (CAR), and agar (AG)) were utilized to prepare microgel beads that were then immersed in zein solutions (70% ethanol aqueous solution, 70% urea aqueous solution, and zein in 70% acetic acid, respectively), thereby facilitating the controlled, slow antisolvent precipitation of the protein layer on the microbead surfaces and inducing hydrophilic hydrophobic core-shell structure formation. This technique can be readily applied to a range of gelling systems and can be tailored to target particle sizes and shell thicknesses. The resultant core-shell particles offer great promise for controlled delivery of fragrances, drugs, or other bioactive compounds in an application-specific fashion, and can be individually tailored based upon the selected input concentrations and preparation methods. Importantly, this technique is generalizable and can be extended to prepare diverse particles with a range of core-shell structures produced from a wide assortment of hydrophobic materials.