Folic acid functionalized reduction-responsive magnetic chitosan nanocapsules for targeted delivery and triggered release of drugs.

A versatile folic acid (FA)-functionalized reduction-responsive magnetic chitosan (CS) nanocapsules (FA-RMCNCs) were designed and fabricated successfully from FA-functionalized thiolated chitosan with a simple sonochemical method. The targeting molecule (FA), red fluorescent probes (Rhodamine B isothiocyanate, RITC) and thiolated Fe3O4 magnetic nanoparticles (Fe3O4-SH MNPs) were immobilized in and onto the shells of nanocapsules. The as-synthesized FA-RMCNCs had a well-defined spherical morphology with the size of 200-350nm. As the carriers, FA-RMCNCs showed an excellent magnetic responsive property. The CLSM analysis revealed that the proposed FA-RMCNCs with core-shell constructure could be internalized selectively by the HeLa cells through the folate-mediated endocytosis. Moreover, the reductant-triggered release of coumarin 6 suggested that the FA-RMCNCs possessed superior reduction-responsivity of drug release. This study reveals the potential of FA-RMCNCs as magnetic/reduction dual-responsive, folate-receptor-mediated targeting nanocarriers in targeted delivery and controlled release of hydrophobic drugs.