Self-Assembly MoS2@MnO2 Nanoflowers for the Fluorescence/Magnetic Resonance Dual-Modal Sensing of H2O2 and Photothermal Therapy

The functions of bioimaging and photothermal therapy integrated into a theranostic nanosystem to prove its diagnostic and therapeutic capabilities are desirable. The versatile molybdenum disulfide (MoS2) dots doped with manganese dioxide (MnO2) nanoflowers (MoS2@MnO2 NFs) were designed for the dual-modal fluorescence/magnetic resonance (MR) sensing/imaging of intracellular H2O2, as well as thermal/MR imaging-guided photothermal therapy in vivo. The MnO2 nanosheets in MoS2@MnO2 NFs acted as an H2O2-mediated initiator, exhibiting fluorescence recovery and Mn2+-related MR signal enhancement through specific H2O2-induced MnO2 sheet degradation. Under the optimal experimental conditions, a dual-modal fluorescence/MR sensor was used to quantitatively detect and image H2O2 and intracellular H2O2, with a limit of detection (LOD) of 0.09 μM. Simultaneously, thermal-responsive MoS2@MnO2 NFs showed robust photothermal cytotoxicity toward cancer cells upon near-infrared (NIR) irradiation, allowing it to serve as a therapeutic drug for thermal/MR imaging-guided photothermal therapy in vivo. This integrated theranostic nanosystem demonstrated its power for multimodal bioimaging and enhanced therapeutic therapy while reducing biotoxicity in mice.