Biodegradable Hollow MoSe₂/Fe₃O₄ Nanospheres as the Photodynamic Therapy-Enhanced Agent for Multimode CT/MR/IR Imaging and Synergistic Antitumor Therapy

Photodynamic therapy (PDT) is considered as one of the most effective cancer treatment strategies because of its minimally invasive and high efficiency. On account of the correlation between PDT and photocatalytic oxidation, the hollow MoSe₂/Fe₃O₄ (MF-2) nanoheterostructure was constructed to enhance PDT as shown in this paper. The size and the hollow structure can be well controlled by the addition of F-127. MoSe₂/Fe₃O₄ reveals the twofold reactive oxygen species (ROS) generation in contrast to the pure MoSe₂, which is ascribed to the effective separation of photogenic charges. The novel hollow structure also supplies a lot of cavities for perfluorocarbon (PFC) and O₂ loading, and O₂@PFC@MF-2 can effectively overcome the hypoxic microenvironment to further cause more than 3 times ROS production. Moreover, the narrow band gap and hollow structure also make sure that the strong near-infrared (NIR) light absorption and high photothermal conversion efficiency is as high as 66.2%. Furthermore, the combination of Fe₃O₄ can further accelerate the effective biodegradation capacity of MF-2 because of the repeated endogenous redox reaction to form water-soluble Mo^VI-oxide species. Meanwhile, doxorubicin (Dox, anticancer drug) was assembled onto the MF-2@PEG nanomaterials through π–π staking and electrostatic interaction for chemotherapy. O₂@PFC@MF-2@PEG/Dox possesses the potential application in triple-model computed tomography, magnetic resonance, and infrared (CT/MR/IR) imaging-guided photothermal/photodynamic/chemotherapy (PTT/PDT/chemotherapy) nanodiagnosis platforms.