Defective Black Nano-Titania Thermogels for Cutaneous Tumor-Induced Therapy and Healing

Current challenges in cutaneous tumor therapy are healing the skin wounds resulting from surgical resection and eliminating possible residual tumor cells to prevent recurrence. To address this issue, bifunctional biomaterials equipped with effective tumor therapeutic capacity for skin cancers and simultaneous tissue regenerative ability for wound closure are highly recommended. Herein, we report an injectable thermosensitive hydrogel (named BT-CTS thermogel) with the integration of nanosized black titania (B-TiO_{2- x}, ∼50 nm) nanoparticles into a chitosan (CTS) matrix. The B-TiO_{2- x} nanocrystal exhibits a crystalline/amorphous core-shell structure with abundant oxygen vacancies, which endows the BT-CTS thermogels with simultaneous photothermal therapy (PTT) and photodynamic therapy (PDT) effects under single-wavelength near-infrared laser irradiation, leading to an excellent therapeutic effect on skin tumors in vitro and in vivo. Moreover, the BT-CTS thermogel not only supports the adhesion, proliferation, and migration of normal skin cells but also facilitates skin tissue regeneration in a murine chronic wound model. Therefore, such BT-CTS thermogels with easy injectability, excellent thermostability, and simultaneous PTT and PDT efficacy as well as tissue regenerative activity offers a promising pathway for the healing of cutaneous tumor-induced wounds.