Construction of aerogels based on N-halamine and chitosan as wound dressing materials with excellent bactericidal and on-demand dissoluble properties.

To address the clinical challenge of wound infection and secondary injury caused by frequent dressing changes during wound healing, this study aims to develop a chitosan-based aerogel dressing with on-demand dissoluble and efficient antibacterial functionality. A low-temperature alkaline urea dissolution strategy enabled the fabrication of chitosan aerogels (CS) through thermally induced gelation, solvent exchange, and freeze-drying. Subsequent ultrasonic-assisted adsorption of N-halamine 1,3-dichloro-5,5-dimethylhydantoin (MC) yielded functionalized N-halamine-loaded chitosan aerogels (CS-MC). Systematic optimization established 2.0 % CS (based on apparent density, porosity, and ethanol adsorption) and 1.5 % MC loading (determined via swelling kinetics, chlorine release profiles, and antibacterial efficacy) as optimal parameters. 2.0 % CS-1.5 % MC had high effective antibacterial effect. The killing rates of E. coli and S. aureus were 78.57 % and 80.30 % at 1 min, respectively, and the killing rates of both bacterial reached 100 % within 5 min. CS-MC dressings were completely dissolved in a dilute acetic acid solution within 20 min. CS-MC aerogels maintain high fibroblast viability, above the 70 % defined by ISO 10993-5 cytotoxicity threshold, achieving an optimal balance between efficient bactericide and histocompatibility. In summary, CS-MC exhibit high antibacterial efficacy and on-demand dissoluble properties, making them suitable for medical dressings.