NIR-activated magnetic resonance nanoprobes for combined photothermal therapy and chemotherapy of cancer

Abstract

Multimodal cancer treatment regimens that combine diagnosis with therapy have received considerable attention in recent years. This study focused on the fabrication of near-infrared (NIR)-activated Fe₃O₄-DNA-DTPA-Gd NPs intended for imaging, thermotherapy, and chemotherapy of cancer. The successful synthesis of Fe₃O₄, oligonucleotide conjugates, and DTPA-Gd was verified by XRD, FTIR, ¹H NMR, and ICP-OES. The bare and citrate-coated Fe₃O₄ aggregated into cubic NPs of 100 nm in size and showed desirable photothermal conversion efficiency of 18.26 %. In addition, the DOX@Fe₃O₄-DNA-DTPA-Gd NPs could disassemble and release DOX when the temperature reached 42 °C due to the denaturation of oligonucleotide moiety upon 808 nm laser light irradiation (0.65 W/cm²). Moreover, the cellular trafficking study revealed the presence of intense red fluorescence in the cytosol of MCF-7/ADR cells due to the internalization of DOX@Fe₃O₄-DNA-DTPA-Gd NPs. Under NIR light illumination, both Fe₃O₄-DNA-DTPA-Gd and DOX@Fe₃O₄-DNA-DTPA-Gd NPs suppressed the proliferation of MCF-7/ADR cells, 38.31 % and 19.40 % cell viability at 20 μM DOX and 157 ppm Fe³⁺ concentration, respectively. Furthermore, the Fe₃O₄-DNA-DTPA-Gd NPs displayed T₂/T₁ switchable property, in the presence of applied magnetic field, suggesting the feasibility of the design for multimodal MRI, photothermic and chemotherapeutic treatment of cancer.