Injectable Thermogel‐Loaded Bi ₂ S ₃ Nanorods for Synergistic Photothermal Bacterial Elimination and Anti‑Inflammation to Remodel Periodontitis Microenvironment

Periodontitis is a prevalent chronic inflammatory disease driven by bacterial infection, whose treatment remains challenging due to persistent inflammation and limited tissue regeneration. Here, we developed an injectable and thermosensitive hydrogel (Bi₂S₃@Gel) composed of hyaluronic acid/Pluronic F127 and Bi₂S₃ nanorods (Bi₂S₃ NDs), which synergistically combines antibacterial and anti-inflammatory functions. Under near‑infrared (NIR) irradiation, Bi₂S₃@Gel exhibits excellent photothermal properties. It generates mild hyperthermia while simultaneously amplifying reactive oxygen species (ROS) and depleting glutathione (GSH), leading to effective bacterial eradication. Simultaneously, the hyaluronic acid matrix prolongs local retention, suppresses M1 macrophage polarization, and promotes tissue repair. In vitro studies confirm favorable biocompatibility, potent antibacterial activity, and effective immunomodulation. In vivo, Bi₂S₃@Gel accelerates diabetic wound healing and promotes periodontal regeneration comparable to minocycline treatment, as evidenced by reduced inflammation, enhanced collagen deposition, and significant alveolar bone restoration. Collectively, Bi₂S₃@Gel integrates antibacterial, anti‑inflammatory, and regenerative capabilities, offering a promising therapeutic platform for periodontitis and other chronic infectious diseases.