Molybdenum disulfide (MoS₂), a typical transition-metal dichalcogenide, has attracted increasing attention in the field of nanomedicine because of its preeminent properties. In this study, magnetic resonance imaging (MRI)-guided chemo-photothermal therapy of human breast cancer xenograft in nude mice was demonstrated using a novel core/shell structure of Fe₃O₄@MoS₂ nanocubes (IOMS NCs) via the integration of MoS₂ (MS) film onto iron oxide (IO) nanocubes through a facile hydrothermal method. After the necessary PEGylation modification of the NCs for long-circulation purposes, such PEGylated NCs were further capped by 2-deoxy-D-glucose (2-DG), a non-metabolizable glucose analogue to increase the accumulation of the as-prepared NCs at the tumor site, as 2-DG molecules could be particularly attractive to resource-hungry cancer cells. Such 2-DG-modified PEGylated NCs (IOMS-PEG-2DG NCs) acted as drug-carriers for doxorubicin (DOX), which could be easily loaded within the NCs. The obtained IOMS-PEG(DOX)-2DG NCs exhibited a T₂ relaxivity coefficient of 48.86 (mM)^-1·s^-1 and excellent photothermal performance. 24 h after intravenous injection of IOMS-PEG(DOX)-2DG NCs, the tumor site was clearly detected by enhanced T₂-weighted MRI signal. Upon exposure to an NIR 808-nm laser for 5 min at a low power density of 0.5 W·cm^-2, a marked temperature increase was noticed within the tumor site, and the tumor growth was efficiently inhibited by the chemo-photothermal effect. Therefore, our study highlights an excellent theranostic platform with great potential for targeted MRI-guided precise chemo-photothermal therapy of breast cancer.

Recently, increasing attention has been paid to magneto-conjugated polymer core–shell nanoparticles (NPs) as theranostic platforms. However, the utilization of surfactants and extra oxidizing agents with potential toxicity in synthesis, the lack of general methods for the controlled synthesis of various kinds of magnetic NP (MNP)@conjugated polymer NPs, and the difficulty of obtaining balanced magneto-optical properties have greatly limited the applications of magneto-conjugated polymers in theranostics. We developed an in situ surface polymerization method free of extra surfactants and oxidizing agents to synthesize MNP@polypyrrole (PPy) NPs with balanced, prominent magneto-optical properties. MNP@PPy NPs with an adjustable size, different shapes, and a controlled shell thickness were obtained using this method. The method was extended to synthesize other MNP-conjugated polymer core–shell NPs, such as MNP@polyaniline and MNP@poly(3, 4-ethylenedioxythiophene): poly(4- styrenesulfonate) (PEDOT: PSS). We discuss the formation mechanism of the proposed method according to our experimental results. Finally, using the optical and magnetic properties of the obtained MNP@PEDOT: PSS NPs, in vivo multimodal imaging-guided hyperthermia was induced in mice, achieving an excellent tumor-ablation therapeutic effect. Our work is beneficial for extending the application of MNP-conjugated polymer core–shell NPs in the biomedical field.