Hollow iron oxide nanoparticles as multidrug resistant drug delivery and imaging vehicles

Magnetic nanoparticles have been used as drug delivery vehicles against a number of cancer cells. Most of these theranostic formulations have used solid iron oxide nanoparticles (SIONPs) loaded with chemotherapeutics as nano-carrier formulation for both magnetic resonance imaging (MRI) and cancer therapy. In this study, we applied the dopamine-plus-human serum albumin (HSA) method to modify hollow iron oxide nanoparticles (HIONPs) and encapsuated doxorubicin (DOX) within the hollow porous structure of the nano-carrier. The new delivery system can load more drug than solid iron oxide nanoparticles of the same core size using the same coating strategy. The HIONPs–DOX formulation also has a pH-dependent drug release behaviour. Compared with free DOX, the HIONPs–DOX were more effectively uptaken by the multidrug resistant OVCAR8-ADR cells and consequently more potent in killing drug resistant cancer cells. MRI phantom and cell studies also showed that the HIONPs–DOX can decrease the T₂ MRI signal intensity and can be used as a MRI contrast agent while acting as a drug delivery vehicle. For the first time, the dual application of chemo drug transport and MR imaging using the HIONPs–DOX formulation was achieved against both DOX-sensitive and DOX-resistant cancer cells.