Injectable Nanocomposite Hydrogels with the NIR-Triggered Low-Temperature Photothermal Effect and Low-Dose Antibiotic Release

Bacterial infection threatens tissue wound healing in clinical practice, so it is essential to construct a safe and efficient antibacterial dressing. In this work, an injectable efficient antibacterial hydrogel is designed to treat bacterial infection disease through the near-infrared (NIR)-triggered low-temperature photothermal effect (below 50 °C) and low-dose antibiotic synergistic therapy. A series of nanocomposite hydrogels (COTC) for antibacterial therapy are synthesized by Schiff base consisting of carboxymethyl chitosan (CMCS), oxidized sodium alginate (OSA), tobramycin (TOB), and cobalt sulfide nanoparticles. The released TOB is controlled in a low dosage through the degradation of Schiff base between TOB and OSA. The biocompatibility assays prove that the hydrogels have excellent biocompatibility. Under NIR irradiation for 10 min, the COTC hydrogels display efficient and controllable photothermal properties (48 °C) and excellent antibacterial efficiency of 99.92 and 99.73% against Escherichia coli and Staphylococcus aureus, respectively. Therefore, these injectable synergistic antibacterial COTC hydrogels exhibit excellent potential for infected wound healing as wound dressing.