Two-dimensional MXene-based materials for photothermal therapy

MXenes, a new family of two-dimensional materials, are also known as transition metal carbides and nitride, with a general formula of M_n+1X_nT_x (n = 1–3). Their inherent metallic conductivity and hydrophilic nature endow MXenes with fascinating physicochemical properties (optical, electronic, magnetic, light-to-heat conversion. etc.). The ultrathin layer structure and photothermal property attract many interests in biomedical applications, especially as phototherapeutic agents for cancer treatment. In this review, we summarize the recent progress of MXenes in the field of photothermal therapy and highlight the crucial biotic index for their preparation and evaluation. First, we introduce the main strategies for the preparation and surface modifications of biologically applied MXenes. Then, representative cases in the field of MXene-based photothermal application, such as photothermal therapy, synergistic therapy, and targeting treatments, are reviewed. Finally, the cytotoxicity and in vivo long-term biosafety are introduced. We also propose the underlying challenges and perspectives for MXene applications in terms of photothermal therapy.