Superparamagnetic Gadolinium Ferrite Nanoparticles with Controllable Curie Temperature ¡V 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 T 1 ¡VT 2 dual-model magnetic resonance (MR) imaging (where T 1 and T 2 are the longitudinal and transverse relaxation times, respectively) is reported. A small amount of Gd doping decreases the T C of 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 ¡V1 ), 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 T 1 ¡VT 2 dual-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. ? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim