Injectable Thermogel-Loaded Bi2S3 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.