Superparamagnetic Gadolinium Ferrite Nanoparticles with Controllable Curie Temperature – Cancer Theranostics for MR-Imaging-Guided Magneto-Chemotherapy

A facile polyol approach for preparing low-Curie-temperature (T_C) gadolinium-doped iron oxide nanoparticles (GdIO NPs) for targeted magnetic hyperthermia and chemotherapy coupled with T₁–T₂dual-model magnetic resonance (MR) imaging (where T₁and T₂are the longitudinal and transverse relaxation times, respectively) is reported. A small amount of Gd doping decreases the T_Cof iron oxide down to about 400 K. In the presence of ethanolamine, controlled polyol synthesis leads to the formation of low-T_C, highly magnetic (52.87 emu g^–1), and size-controlled (ca. 10 nm) GdIO NPs. A further conjugation with folate and a chemotherapeutic drug has been developed, and the whole system is used for in vitro magneto-chemotherapy (magnetic hyperthermia and chemotherapy) for cancer treatment. The synthesized GdIO NPs are stable colloids that are hemocompatible and cytocompatible over a wide concentration range and have a high affinity towards cancer cells. The release of a chemotherapeutic drug from the GdIO NPs significantly affects cancer cell viability, and the T₁–T₂dual-model magnetic resonance enhances bioimaging in a breast cancer cell model. We suggest that the chemotherapeutic-drug-conjugated GdIO NPs have great potential for cell targeting and magnetic resonance imaging in cancer magneto-chemotherapy.