Eddy current thermal effect based on magnesium microrods for combined tumor therapy

Magnetic hyperthermia therapy (MHT) is a minimally invasive cancer treatment to ablate tumors under an alternating magnetic field (AMF), possessing advantages including excellent tissue penetration, tumor-targeted selectivity, and negligible damage to the normal tissues. However, the low magnetothermal conversion efficiency (MTCE) of the magnetocaloric nanoagents limits its application. Herein, magnesium @ doxorubicin (Mg@DOX) microrods were prepared by electrospinning technology for the combined MHT and chemotherapy under AMF. The constructed Mg@DOX rods exhibited apparent magnetic field intensity-dependent temperature rise under AMF, stemming from the eddy thermal effect with good thermal stability, outstanding MTCE, and excellent penetration depth. Meanwhile, the DOX release increased with the prolonged magnetothermal time and the decreased pH value, thus realizing combined therapy. In vitro experiments showed that Mg@DOX microrods had an obviously cell-killing ability on account of the MHT and accelerated DOX release. In vivo experiments were further performed by implanting Mg@DOX microrods into 4T1 mouse breast tumors and the deep-seated rat liver tumors, showing excellent combined therapeutic effects. Moreover, Mg@DOX microrods showed excellent biocompatibility and displayed insignificant toxicity to the implanted animals. Our work highlighted the effective combined therapy of the unique eddy thermal effect of Mg@DOX microrods.