The theranostic nanoagent Mo₂C for multi-modal imaging-guided cancer synergistic phototherapy

Multifunctional theranostic platforms, especially single component-based platforms, enable both cancer treatment and real-time imaging as well as enhance the efficiency of treatment. In this study, 50 nm Mo₂C nanospheres were explored as a "one-for-all" theranostic agent. The light-harvesting of Mo₂C covered the entire near infrared region, and NIR irradiation concurrently triggered hyperthermia and reactive oxygen species (ROS) production; thus, synergistic outcomes of photothermal and photodynamic therapy could be realized. Both in vitro and in vivo experiments have confirmed the superiority of the synergistic phototherapy in killing cancer cells and removing solid tumors; moreover, Mo₂C proposed herein has been proven to be applicable as a photoacoustic imaging and CT imaging contrast agent for in vivo tumor depiction; furthermore, Mo₂C demonstrates excellent biocompatibility, showing minimal hematotoxicity and tissue toxicity. A theoretical simulation performed by density functional theory revealed that the metallic character and the interband/intraband transition of Mo₂C accounted for its broad photoabsorption. The antitumor mechanism of Mo₂C was investigated on a solid tumor by B-mode ultrasonography (US) and magnetic resonance imaging (MRI), revealing a typical liquefactive necrosis process; hence, herein, the dual-imaging guided phototherapy was efficiently mediated by Mo₂C.