Biodegradable and Excretable 2D W(1.33)C i‐MXene with Vacancy Ordering for Theory‐Oriented Cancer Nanotheranostics in Near‐Infrared Biowindow

MXenes, a new class of two‐dimensional (2D) nanomaterials, have shown enormous potential for biological applications. Notably, the development of 2D MXenes in nanomedicine is still in its infancy. Herein, a distinct W(1.33)C i‐MXene with multiple theranostic functionalities, fast biodegradation, and satisfactory biocompatibility is explored. By designing a parent bulk laminate in‐plane ordered (W(2/3)Y(1/3))(2)AlC ceramic and optionally etching aluminum (Al) and yttrium (Y) elements, 2D W(1.33)C i‐MXene nanosheets with ordered divacancies are efficiently fabricated. Especially, theoretical simulations reveal that W(1.33)C i‐MXene possesses a strong predominance of near‐infrared (NIR) absorbance. The constructed ultrathin W(1.33)C nanosheets feature excellent photothermal‐conversion effectiveness (32.5% at NIR I and 49.3% at NIR II) with desirable biocompatibility and fast degradation in normal tissue rather than in tumor tissue. Importantly, the multimodal‐imaging properties and photothermal‐ablation performance of W(1.33)C‐BSA nanosheets are systematically revealed and demonstrated both in vitro and in vivo. The underlying mechanism and regulation factors for the W(1.33)C‐BSA nanosheets‐induced hyperthermia ablation are also revealed by transcriptome and proteome sequencing. This work offers a paradigm that i‐MXenes achieve the tailoring biomedical applications through composition and structure design on the atomic scale.