In vivo anti-cancer efficacy of magnetite nanocrystal--based system using locoregional hyperthermia combined with 5-fluorouracil chemotherapy.

We present an approach for synchronizing hyperthermia and thermal-responsive local drug release. The targeting probe has a magnetite nanocrystal (Fe₃O₄@PSMA) core and a polynucleotide shell that carries 5-fluorouracil (5-FU) and anti-human epidermal growth factor receptor 2 (anti-HER2) antibody for cancer cell-specific targeting. The targeting nanocrystals play as an important role to relay the externally delivered radiofrequency energy for tumor hyperthermia. Locoregional heat then triggers a drug release from the oligonucleotide carrier as it directly damages tumor cells. Cell viability assays and pathological examinations show that this synchronization is significantly more efficacious in both in vitro and in vivo models than hyperthermia or chemotherapy alone. Prominent tumor remission in vivo was achieved through radiofrequency synchronization of hyperthermia and chemotherapy after the nanoparticle had been intravenously injected.