Biocompatible 2D Titanium Carbide (MXenes) Composite Nanosheets for pH-Responsive MRI-Guided Tumor Hyperthermia

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 (MnOx/Ti3C2) for highly efficient theranostic applications against cancer. These MnOx/Ti3C2 composite MXenes have been constructed by triggering a simple redox reaction to in situ grow small MnOx nanosheets on the surface of Ti3C2. These MnOx/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 MnOx component onto MnOx/Ti3C2 realizes the unique tumor microenvironment-responsive T-1-weighted MR imaging of tumors, and the high photothermal-conversion performance not only endows the MnOx/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 MnOx/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.