A Bi₂S₃-embedded gellan gum hydrogel for localized tumor photothermal/antiangiogenic therapy

An injectable gellan gum-based nanocomposite hydrogel (Bi₂S₃@GG) was designed for X-ray computed tomography (CT) imaging and photothermal/antiangiogenic therapy. The linear anionic polysaccharide gellan gum (GG) was used as a stabilizer, embedded with ultra-small bismuth sulfide (Bi₂S₃) nanodots (∼2 nm) through a one-pot synthesis method. The as-prepared Bi₂S₃@GG hydrogel displays excellent capability for both photothermal therapy (PTT) (with a photothermal conversion efficiency of 44.3%) and X-ray computed tomography (with an X-ray absorption coefficient of 51.5 HU L g^-1), integrated with real-time monitoring drug retention and tunable therapeutic functions. After the incorporation of sorafenib (SF), the hydrogel shows a sustained release of SF over 15 days. A tumor suppression rate of 98.2% is shown at day 22 postinjection in the mice received the combined treatments of photothermal/antiangiogenic therapy. In contrast, tumor growth and recurrence are observed in the single treatment. Our work presents a new strategy to construct a multifunctional hydrogel platform for a safe and precise antitumor therapy.