Copper Manganese Sulfide Nanoplates: A New Two-Dimensional Theranostic Nanoplatform for MRI/MSOT Dual-Modal Imaging-Guided Photothermal Therapy in the Second Near-Infrared Window

Multifunctional nanoplatforms with integrated diagnostic and therapeutic functions have attracted tremendous attention. Especially, the second near-infrared (NIR-II) light response-based nanoplatforms hold great potential in cancer theranostic applications, which is because the NIR-II window provides larger tissue penetration depth and higher maximum permissible exposure (MPE) than that of the well-studied first near-infrared (NIR-I) window. Herein, we for the first time present a two-dimensional (2D)-nanoplatform based on Cu(2)MnS(2) nanoplates (NPs) for magnetic resonance imaging (MRI)/multispectral optoacoustic tomography (MSOT) dual-modal imaging-guided photothermal therapy (PTT) of cancer in the NIR-II window. Methods: Cu(2)MnS(2) NPs were synthesized through a facile and environmentally friendly process. A series of experiments, including the characterization of Cu(2)MnS(2) NPs, the long-term toxicity of Cu(2)MnS(2) NPs in BALB/c nude mice, the applications of Cu(2)MnS(2) NPs for in vitro and in vivo MRI/MSOT dual-modal imaging and NIR-II PTT of cancer were carried out. Results: The as-synthesized Cu(2)MnS(2) NPs exhibit low cytotoxicity, excellent biocompatibility as well as high photothermal conversion efficiency (~49.38%) and outstanding photostability. Together with their good T(1)-shortening effect and strong absorbance in the NIR-I and NIR-II region, the Cu(2)MnS(2) NPs display high-contrast imaging performance both in MRI and MSOT (900 nm laser source). Moreover, the subsequent in vitro and in vivo results demonstrate that the Cu(2)MnS(2) NPs possess excellent PTT efficacy under 1064 nm laser irradiation with a low power density (0.6 W cm(-2)). In addition, the detailed long-term toxicity studies further confirming the safety of Cu(2)MnS(2) NPs in vivo. Conclusion: We have developed a new 2D Cu(2)MnS(2) NPs as multifunctional theranostic agents for MRI/MSOT dual-modal imaging-guided PTT of cancer in the NIR-II window. Such biocompatible Cu(2)MnS(2) NPs might provide a new perspective for exploring new 2D-based nanoplatforms with improved properties for clinical applications in the future.