Multifunctional antimicrobial wound dressing with photothermal promotion based on Bletilla striata polysaccharides...

Wound healing is often hindered by bacterial infection, oxidative stress, and bleeding. Traditional dressings cannot simultaneously regulate multiple microenvironments. To address the shortcomings of traditional dressings, this study constructed a dual-network photothermal responsive multifunctional hydrogel OBCTCu based on four natural ingredients, including Bletilla striata polysaccharide (BSP), chitosan (CS), tannic acid (TA), and Cu²⁺. Firstly, we systematically characterized the structural integrity of OBCTCu hydrogels, with an Oxidized Bletilla striata polysaccharide (OBSP) oxidation degree of 31.93 %. The hydrogel can rapidly absorb exudate (absorbing 6 times its own weight within 1 h) and maintain a moist wound environment. It also possesses multifunctional properties such as self-healing, self-adaptation, injectability, near-infrared (NIR) responsiveness, and adhesiveness. The OBCTCu hydrogel exhibits broad-spectrum antibacterial activity against Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans). Among these, the antibacterial effect against C. albicans is the most significant (minimum inhibitory concentration (MIC) 0.1 g/mL, minimum bactericidal concentration (MBC) 0.2 g/mL), achieving 100 % antibacterial activity after near-infrared treatment. Additionally, OBCTCu hydrogel can efficiently remove various reactive oxygen species and achieve rapid hemostasis. In the vivo wound healing experiment shows that the OBCTCu hydrogel can significantly promote wound healing. The excellent biocompatibility of this hydrogel makes it safe for clinical application (cell viability >80 % in all groups, hemolysis rate < 3 %). This study innovatively combines natural active ingredients with green synthesis strategies to provide a novel non-antibiotic dressing solution for drug-resistant bacterial infections. The solution features mechanical adaptability, smart response, and multifunctional integration.