Injectable natural hydrogel loaded with Fe2B2 nanosheets-Salvianolic acid A nanocomposite for photothermal/photodynamic therapy of acute sinusitis

The treatment of acute sinusitis faces dual challenges of drug delivery and antibiotic resistance. Traditional Chinese medicine composite nanomaterials show tremendous potential for therapy. We combined the traditional Chinese medicine Salvianolic acid A (SAA) with Fe 2 B 2 nanosheets, then encapsulated the modified Fe 2 B 2 nanosheets within a hydrogel matrix containing alginate oligosaccharides (AOS) and chitosan (CS), resulting in an injectable AOS/CS@Fe 2 B 2 @SAA hydrogel. Characterization demonstrated excellent gelling properties and sustained-release characteristics. Cellular studies confirmed high biocompatibility. Bacterial culture, Live/Dead cell staining experiments, CT scans, and histological staining collectively demonstrated the anti-inflammatory and antibacterial effects of this hydrogel at the cellular, individual, and tissue levels. This hydrogel demonstrated remarkable synergistic effects in photothermal therapy and photodynamic therapy: the dual action effectively inhibited pathogen growth (with a photothermal conversion efficiency of 37.9%). Furthermore, the hydrogel can regulate macrophage polarization and associated cytokine secretion, exerting dual antioxidant and anti-inflammatory effects: post-treatment ROS levels in macrophages significantly decreased, while the proportion of M1 macrophages significantly dropped. Additionally, the secretion of key proinflammatory factors, IL-6 and TNF-α, was markedly decreased. These results fully confirm the efficacy of the hydrogel in mitigating cellular oxidative damage and suppressing inflammatory responses.