a nir-responsive metal-coordinated antibacterial hydrogel for treatment of cancer and promoting wound healing

Aim and background: photothermal therapy (ptt) based on nanoparticles (nps) has intrigued attention due to its clinical applications using natural hydrogels. herein, we reported a ptt-assisted antibacterial system utilizing hyaluronic acid coated bismuth sulfide (bih) nps and allantoin (alla) for high temperature assisted cancer therapy, followed by mild photothermal therapy of subsequent wounds and infections.methods: bih synthesis was carried out through bismuth nitrate pentahydrate and thioacetamide reaction in an acidic environment. the bih and alla incorporated hydrogel was prepared via metal-coordination and physicochemical characterizations of nps and hydrogels as well as the photothermal activity were evaluated. moreover, blood clotting tests, cancer cells removal, antibacterial effect, and in vivo wound healing ability of the prepared hydrogels were assessed.results and discussion: the rod-shape nps synthesized and successfully loaded in the hydrogel. the prepared hydrogel showed good injectability, self-healing capacity, and highly porous structure. the temperature of bih-loaded hydrogel increased after nir irradiation, which is sufficient for cancer ablation. the hydrogel-treated group under 808 nm laser irradiation showed the reduction of tumor volume and increased apoptotic cells in histological analysis in a 4t1 bearing cancer model. moreover, a desirable antibacterial activity was achieved due to the synergistic effect of inherent bactericidal effect of bih nps and ptt as well as improved skin regeneration in an in vivo wound model by mild photothermal therapy. conclusion: this novel multifunctional hydrogel demonstrated excellent hemostatic performance, photothermal-induced cancer cell apoptosis, desirable antibacterial activity, and skin regeneration, which can be used for malignancies and infected wound treatments.