Attenuation of Mouse Melanoma by A/C Magnetic Field after Delivery of Bi-Magnetic Nanoparticles by Neural Progenitor Cells

Localized magnetic hyperthermia as a treatment modality for cancer has generated renewed interest, particularly if it can be targeted to the tumor site. We examined whether tumor-tropic neural progenitor cells (NPCs) could be utilized as cell delivery vehicles for achieving preferential accumulation of core/shell iron/iron oxide magnetic nanoparticles (MNPs) within a mouse model of melanoma. We developed aminosiloxane−porphyrin functionalized MNPs, evaluated cell viability and loading efficiency, and transplanted neural progenitor cells loaded with this cargo into mice with melanoma. NPCs were efficiently loaded with core/shell Fe/Fe<sub>3</sub>O<sub>4</sub> MNPs with minimal cytotoxicity; the MNPs accumulated as aggregates in the cytosol. The NPCs loaded with MNPs could travel to subcutaneous melanomas, and after A/C (alternating current) magnetic field (AMF) exposure, the targeted delivery of MNPs by the cells resulted in a measurable regression of the tumors. The tumor attenuation was significant (<i>p</i> < 0.05) a short time (24 h) after the last of three AMF exposures.