Doxorubicin-loaded Fe₃O₄@MoS₂-PEG-2DG nanocubes as a theranostic platform for magnetic resonance imaging-guided chemo-photothermal therapy of breast cancer

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.