Chitosan/silver nanoparticles confined within halloysite nanotube composite sponge for synergistic antibacterial and photothermal therapy of infected diabetic wounds

Diabetic wounds frequently develop infections and impaired healing due to the hyperglycemic microenvironment, creating a need for dressings with combined antibacterial and tissue-regenerative functions. Here, the lumens of halloysite nanotubes (HNTs) were employed for confined in-situ synthesis of silver nanoparticles (Ag@HNTs), which were then incorporated into a chitosan matrix by solution mixing and freeze-drying to produce porous Ag@HNTs-CS sponges. The lumen-confined synthesis generated uniformly distributed Ag nanoparticles in the HNT lumens, which reduced aggregation and direct cell contact, thereby lowering toxicity and enabling sustained Ag + release. The composite exhibited triple antibacterial functionality, combining bactericidal effects mediated by chitosan, Ag + sustained release, and enhanced photothermal activity under 808 nm irradiation, strongly inhibiting E. coli and S. aureus . In a diabetic rat model with infected full-thickness skin defects, these sponges significantly promoted wound healing. Mechanistically, the sponges reduced TNF- α , increased IL-10 and VEGF, mitigating inflammation while enhancing neovascularization and collagen deposition. The confined-synthesis of metal nanoparticles within the HNT lumens and incorporation into a biopolymer matrix ensures sustained metal ion release, high photothermal performance and bioactivity, which offer a promising strategy for infected wound management.