CrB MBene-infused sprayable hydrogel for NIR-I/II photothermal cancer treatment

The unique two-dimensional (2D) architecture and superior photothermal efficacy of 2D materials position them as promising candidates for cancer photothermal therapy (PTT), offering precise energy conversion and targeted tissue penetration. This study innovatively explores the photothermal properties and biological applications of chromium boride (CrB) nanosheets, a novel 2D transition metal borides (MBenes), for postsurgical cancer treatment. Ultrathin CrB nanosheets exhibit superior near-infrared (NIR) absorption with 36.5% and 27.8% photothermal conversion efficiencies in NIR-I/II biowindows, respectively, enabling rapid hyperthermia (ΔT​>20 °C within 30 s) for residual tumor ablation and antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli). When incorporated into a sprayable thermosensitive hydrogel, the CrB@H composite provides conformal coverage and healing-promoting ability for surgical wounds. In murine postoperative tumor models, CrB@H mediated-PTT achieved remarkable tumor recurrence suppression (100% within 16 days) and extended survival (60 days). It also reduced the pro-inflammatory cytokine IL-6 and enhanced collagen deposition, promoting epidermal regeneration in a surgical site infection model induced by MRSA. Comprehensive biosafety evaluation via histological and hematological analyses confirmed negligible systemic toxicity or biochemical abnormalities. By integrating 2D MBene innovation with clinical practicality, this sprayable platform establishes a paradigm for precision PTT, effectively addressing tumor recurrence and postoperative infection.