Magnetic field-induced synergistic therapy of cancer using magnetoplasmonic nanoplatform

Combining photothermal and chemotherapy using single nanoplatform is an emerging direction in cancer nanomedicine. Herein, a magnetic field (MF) induced combination of chemo/photothermal therapy is demonstrated using Fe₃O₄@mSiO₂@Au core@shell@satellites nanoparticles (NPs) loaded with chemotherapeutic drug doxorubicin (DOX), both <i>in vitro</i> and <i>in vivo.</i> An application of an external MF to the NPs dispersion causes magnetophoretic movement and aggregation of the NPs. While the synthesized NPs only slightly absorb light at ∼800 nm, their aggregation results in a significant near infrared (NIR) absorption associated with plasmon resonance coupling between the Au satellites in the NPs aggregates. As a result, the aggregates revealed an enhanced photothermal conversion efficiency (∼67 % versus ∼19 % for NPs in absence of MF) and an enhanced NIR photothermal effect was observed under 808 nm laser irradiation. A combination of the MF induced NIR photothermal therapy (PTT) with DOX chemotherapeutic action resulted in an efficient killing of NPs treated cancer cells <i>in vitro</i> and tumor growth restriction in 4T1-tumor-bearing mice <i>in vivo</i>. Histological studies showed striking differences in development and malignancy between tumors treated with the combination of NPs, MF and an 808 nm laser, and the control treatments, revealing a synergy of the MF-induced NIR PTT and chemotherapy and suggesting a promising strategy for cancer therapy.