A Two-Dimensional Biodegradable Niobium Carbide (MXene) for Photothermal Tumor Eradication in NIR-I and NIR-II Biowindows

TLDR

Ceramics-based materials are widely used as bone scaffolds, yet their potential for cancer phototherapy in NIR‑I and NIR‑II windows has been largely unexplored, despite Nb₂C MXene nanosheets offering enzyme‑responsive biodegradability, low phototoxicity, and high biocompatibility. The study aims to demonstrate that 2D Nb₂C MXene nanosheets can achieve highly efficient in vivo photothermal ablation of mouse tumor xenografts in both NIR‑I and NIR‑II windows, thereby expanding the therapeutic scope of MXenes. The Nb₂C nanosheets were produced via a scalable two‑step liquid exfoliation involving stepwise delamination and intercalation. The ultrathin Nb₂C nanosheets achieved photothermal conversion efficiencies of 36.4 % (NIR‑I) and 45.65 % (NIR‑II), displayed high stability, and enabled complete in vivo ablation and eradication of mouse tumor xenografts in both NIR‑I and NIR‑II windows.

Abstract

Conventionally, ceramics-based materials, fabricated by high-temperature solid-phase reaction and sintering, are preferred as bone scaffolds in hard-tissue engineering because of their tunable biocompatibility and mechanical properties. However, their possible biomedical applications have rarely been considered, especially the cancer phototherapeutic applications in both the first and second near-infrared light (NIR-I and NIR-II) biowindows. In this work, we explore, for the first time as far as we know, a novel kind of 2D niobium carbide (Nb2C), MXene, with highly efficient in vivo photothermal ablation of mouse tumor xenografts in both NIR-I and NIR-II windows. The 2D Nb2C nanosheets (NSs) were fabricated by a facile and scalable two-step liquid exfoliation method combining stepwise delamination and intercalation procedures. The ultrathin, lateral-nanosized Nb2C NSs exhibited extraordinarily high photothermal conversion efficiency (36.4% at NIR-I and 45.65% at NIR-II), as well as high photothermal stability. The Nb2C NSs intrinsically feature unique enzyme-responsive biodegradability to human myeloperoxidase, low phototoxicity, and high biocompatibility. Especially, these surface-engineered Nb2C NSs present highly efficient in vivo photothermal ablation and eradication of tumor in both NIR-I and NIR-II biowindows. This work significantly broadens the application prospects of 2D MXenes by rationally designing their compositions and exploring related physiochemical properties, especially on phototherapy of cancer.