Biodegradable and Excretable 2D W_1.33C <i>i</i>‐MXene with Vacancy Ordering for Theory‐Oriented Cancer Nanotheranostics in Near‐Infrared Biowindow

Abstract

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.