The emerging of two-dimensional (2D) MXenes significantly broadens the family members and versatile applications of 2D materials, but the rational design of MXene-based composites and their specific applications in theranostic biomedicine are still challenging. In this work, we report, for the first time, on the elaborate design of the Ti₃C₂-based composite MXene (MnO_x/Ti₃C₂) for highly efficient theranostic applications against cancer. These MnO_x/Ti₃C₂ composite MXenes have been constructed by triggering a simple redox reaction to in situ grow small MnO_x nanosheets on the surface of Ti₃C₂. These MnO_x/Ti₃C₂ composite MXenes have been developed as multifunctional theranostic agents for efficient magnetic resonance (MR) and photoacoustic (PA) dual-modality imaging-guided photothermal therapy (PTT) against cancer. Especially, the decoration of the MnO_x component onto MnO_x/Ti₃C₂ realizes the unique tumor microenvironment-responsive T₁-weighted MR imaging of tumors, and the high photothermal-conversion performance not only endows the MnO_x/Ti₃C₂ with desirable contrast-enhanced PA-imaging property but also realizes the highly efficient tumor ablation and tumor-growth suppression. The in vivo biocompatibility of these MnO_x/Ti₃C₂–SP composite nanosheets has also been systematically evaluated and revealed. This work not only paves a new way for the multifunctionalization of 2D MXenes simply by integrating other functional components but also broadens their versatile applications in theranostic nanomedicine.

中文翻译：

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用于pH响应MRI指导的肿瘤热疗的生物相容性2D碳化钛（MXenes）复合纳米片

二维（2D）MXene的出现极大地拓宽了2D材料的家族成员和用途，但是基于MXene的复合材料的合理设计及其在治疗性生物医学中的特殊应用仍然具有挑战性。在这项工作中，我们首次报告了基于Ti ₃ C ₂的复合MXene（MnO _x / Ti ₃ C ₂）的精心设计，该设计可用于高效的肿瘤治疗应用。这些MnO _x / Ti ₃ C ₂复合MXene是通过触发简单的氧化还原反应以原位生长小MnO _x来构建的Ti ₃ C ₂表面上的纳米片。这些MnO _x / Ti ₃ C ₂复合MXene已开发为多功能治疗剂，可用于有效的磁共振（MR）和光声（PA）双模态成像引导光热疗法（PTT）来治疗癌症。特别是，在MnO _x / Ti ₃ C ₂上装饰MnO _x成分，实现了独特的肿瘤微环境响应性T ₁加权MR成像，并且高的光热转换性能不仅赋予了MnO _x / Ti ₃ C _2个具有理想的对比度增强的PA成像性能，还实现了高效的肿瘤消融和肿瘤生长抑制。在体内这些的MnO生物相容性_X / Ti的₃ c ^ ₂ -SP复合纳米薄片也被系统的评价和揭示。这项工作不仅简单地通过集成其他功能组件为2D MXene的多功能化铺平了道路，而且拓宽了它们在治疗法纳米医学中的通用性应用。