A nanosized, thermo-sensitive drug carrier: self-assembled Fe3O4-OA-g-P(OA-co-NIPAAm) magnetomicelles

Novel thermo-sensitive magnetomicelles that consist of a magnetic core, Fe3O4-oleic acid (Fe3O4-OA), and an amphiphilic surface layer of thermo-sensitive poly(oleic acid-co-N-isopropylacrylamide) P(OA-co-NIPAAm) co-polymer were prepared. Fe3O4 magnetic cores functionalized with double bonds of oleic acid were prepared by suspension-oxidation reaction. Subsequently, by the co-polymerization of hydrophilic NIPAAm, hydrophobic OA and the Fe3O4-OA magnetic core, the thermo-sensitive amphiphilic polymers (P(OA-co-NIPAAm)) were grafted to obtain Fe3O4-OA-g-P(OA-co-NIPAAm) nanoparticles. The surface polymeric layer of Fe3O4-OA-g-P( OA-co-NIPAAm) nanoparticles would self-assemble in aqueous media to form a micellar structure attributed to the amphiphilic P(OA-co-NIPAAm) polymers. The model drug, prednisone acetate, was loaded in the magnetomicelles and in vitro release behavior of loaded drug in magnetomicelles was further investigated, which showed a thermo-sensitive release behavior due to the thermo-sensitive structural changes of the micellar surface layer.