Electrospun polyasparthydrazide nanofibrous hydrogel loading with in-situ synthesized silver nanoparticles for full-thickness skin wound healing application

The long-term exposure of skin wounds, especially for those chronic wounds, is commonly accompanied with the bacterial infection, which further holds back the wound healing process. Therefore, it's urgently required to develop the innovative wound dressings with both antibacterial property and healing-promoting function. In this study, a series of novel hydrogel dressings constructed with polyasparthydrazide (PAHy) nanofibers and different concentrations of in-situ synthesized silver nanoparticles (AgNPs) were designed and prepared. It was found that all the PAHy nanofiber hydrogel mats without or with AgNPs exhibited uniform and bead-free nanofibrous structure, and the AgNPs-contained PAHy nanofiber hydrogel mats showed obviously decreased fiber diameters compared with pure PAHy nanofiber hydrogel mat. The mechanical properties of all as-prepared PAHy/AgNPs nanofiber hydrogel mats in the dry condition were significantly larger than those in the wet condition, and appropriate addition of AgNPs could improve the mechanical properties to some extent. The water swelling ratio of different PAHy/AgNPs hydrogel mats were found to be decreased with the increasing of AgNPs content. The nanofiber hydrogel mat prepared with polysuccinimide (PSI) with 0.5 wt% silver nitrate (AgNO3), named as PAHy/AgNPs-0.5 hydrogel mat, displayed a higher cumulative silver release rate (9.4 ± 1.1 %) after 72 h, and it was demonstrated to possess excellent antibacterial rates against E. coli (99.99 %) and S. aureus (99.99 %), and clear inhibition zones with the diameter of 1.0 ± 0.1 mm for E. coli and 5.8 ± 0.3 mm for S. aureus. Importantly, the animal studies showed that the PAHy/AgNPs-0.5 nanofiber hydrogel mat could significantly accelerate the wound healing process by promoting the re-epithelialization and collagen deposition of wound site, which possessed huge potential for serving as advanced dressing materials for the infected wound treatment.