Sonochemical fabrication of magnetic reduction-responsive alginate-based microcapsules for drug delivery

The magnetic reduction-responsive alginate-based microcapsules (MRAMCs) have been developed successfully with thiolated alginate and oleic acid (OA) modified Fe₃O₄ nanoparticles (OA-Fe₃O₄ NPs) via a facile sonochemical method. The obtained MRAMCs could be used as multifunctional carriers for hydrophobic drugs targeted delivery and triggered release due to their merits, such as biocompatibility, non-immunogenicity, magnetic targeting drug delivery and reduction-responsive drug release. The MRAMCs were endowed with magnetic targeting function owing to the encapsulation of the superparamagnetic OA-Fe₃O₄ NPs, which was confirmed by transmission electron microscope and vibrating sample magnetometer. In addition, the MRAMCs presented excellent reduction-responsive release ability for hydrophobic drugs on account of the disulfide bonds in the wall of microcapsules, which were formed by the cross-linking of sulfhydryl groups on thiolated alginate under ulstrasonication. Meanwhile, confocal laser scanning microscopy measurement indicated that coumarin 6 acted as a hydrophobic model drug could be loaded into MRAMCs easily by dissolving in soybean oil before ultrasonication. Overall, these results demonstrated that MRAMCs would be a promising platform to build controllable drug delivery systems for targeted delivery and triggered release of hydrophobic drugs in biomedical application.