Chitosan aerogel loaded with biogenic palladium nanoparticles CH/Pd NPs exert antibacterial activity and wound addressing application in vitro and in vivo against bacterial skin infections

Bacterial skin infections that infect wounds and burns are considered one of the most serious medical problems that lead to delay wound healing, toxicity and even death. Therefore, there is an urgent need to develop an effective pharmaceutical material that promotes the treating of skin bacterial infections. Within this, we aimed in this study to synthesis and assess the effectiveness of novel chitosan/palladium nanoparticles (CH/Pd NPs) aerogel composites in treating bacterial skin infections and wound healing. Green method was employed for synthesis of Pd NPs using Allium sativum ( A. sativum ) extract, while crosslinking process and freeze-drying cycle were utilized for preparation of CH/Pd NPs aerogel composites. The prepared Pd NPs and CH/Pd NPs aerogel composite were thoroughly characterized using UV -vis, FTIR, XRD and SEM. The GC -MS analysis revealed that the main components in the A. sativum were diallyl disulfide (55.88 %) and diallyl trisulfide (24.34 %) which were among the four identified components. Additionally, the total phenols and flavonoids contents were 61.3 mg GAE/100 g and 18.8 mg QE/100 g, respectively. The swelling capacity of CH/Pd NPs aerogel microspheres reach 400 % with blood compatibility and slightly hemolysis ratio about 0.4 %. In vitro , the antibacterial studies demonstrated that loading Pd NPs with CH aerogel microspheres enhanced their effectiveness against MDR bacteria with complete inhibition for all bacterial strains growth. The CH/Pd NPs aerogel microspheres exhibited a significant inhibitory effect on biofilm formation. The biofilm inhibition percentage was found to be 87 % against the biofilm of S. aureus and 80 % against the biofilm of P. aeruginosa. In vivo infection model in rats, CH and CH/Pd NPs aerogel films stimulated skin tissue formation and healing wounds completely in 6 days with highly reduced in MDR and biofilm producing bacterial count. Finally, CH/Pd NPs aerogel composites represent a promising therapeutic strategy for the effective and enhanced healing of infected wounds.