An injectable hydrogel based on Bi₂Se₃ nanosheets and hyaluronic acid for chemo-photothermal synergistic therapy

To resolve poor accumulation caused by systemic administration, injectable and responsive hydrogels are the prospective drug delivery systems for localized tumor treatment, owning to negligible invasiveness and accurate administration. Herein, an injectable hydrogel, based on dopamine (DA) crosslinked hyaluronic acid and Bi₂Se₃ nanosheets (NSs) loading with doxorubicin (DOX) coated with polydopamine (Bi₂Se₃-DOX@PDA), was developed for synergistic chem-photothermal cancer therapy. The ultrathin functional Bi₂Se₃-DOX@PDA NSs could be responsive to the weak acidic condition and photothermal effect under NIR laser irradiation, achieving controlled release of DOX. Moreover, nanocomposite hydrogel based on hyaluronic acid matrix could be precisely administrated through intratumoral injection since its injectability and self-healing capacity, remaining at injected sites for at least 12 days. Furthermore, the excellent therapeutics effect of Bi₂Se₃-DOX@PDA nanocomposite hydrogel was demonstrated on 4 T1 xenograft tumor with outstanding injectability and negligible systemic side-effect. In short, the construction of Bi₂Se₃-DOX@PDA nanocomposite hydrogel paves a prospective path for local treatment of cancers.