Eudragit S100-based nanofiber membranes for pH-triggered co-release of iridium nanozymes and roxithromycin in antioxidant and antibacterial therapy

The vicious cycle of reactive oxygen species (ROS) overload and bacterial infection critically impedes diabetic wound healing. While nanozyme-antibiotic dressings offer therapeutic potential, their uncontrolled agent release remains a key challenge. In this study, a functional nanofiber membrane (EIPR) based on the pH-sensitive polymer Eudragit S100 was fabricated via coaxial electrospinning to load iridium nanozymes (Ir NPs-PVP) and roxithromycin (Rox), enabling on-demand release of therapeutic agents for combined antibacterial and antioxidant wound therapy. The obtained dressing displays highly precise and controllable therapeutic agent release characteristics. Rox shows approximately 90 % cumulative release at pH 7.4, while release is suppressed to <8 % at pH 6.0 and 4.5. Notably, the release trend of Ir NPs-PVP mirrors that of Rox, with significantly higher release under alkaline conditions. The results exhibit >97 % eradication of both Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ) coupled with >75 % ROS clearance at pH 7.4. This study presents a novel dual-function system, highlighting the simplicity and efficiency of electrospinning technology, which are key advantages enhancing its scalability for large-scale manufacturing and suitability for clinical wound care translation.