Design of novel bioadhesive chitosan film loaded with bimetallic gold-silver nanoparticles for antibiofilm and wound healing activity

Microbial infections and antibiotic resistance are among the leading causes of morbidity and mortality worldwide. The bimetallic chitosan (CS)-capped gold-silver nanoparticles (CS-AuAg-NPs) were prepared by the seeded growth synthesis technique. The nanoparticles were optimized for particle size (PS), zeta potential (ZP) and antibacterial activity by Box–Behnken design at three levels and three factors. The developed CS-AuAg-NPs were polydispersed with mean hydrodynamic PS in the range of 55 – 289 nm and ZP ranges from +8.53 mV to +38.6 mV. The optimized CS-AuAg-NPs found to have a minimum inhibitory concentration and minimal bactericidal concentration of 1.625 ± 0.68 and 3.25 ± 0.74 µg ml−1 towards multidrug resistant (MDR) Staphylococcus aureus ATCC 25923 (MDR AT) and 3.25 ± 0.93 and 3.25 ± 0.86 µg ml−1 towards MDR S. aureus clinical isolate MDR1695 (MDR CI) strain, respectively. The CS-AuAg-NPs were much more effective against MDR AT and MDR CI compared to clindamycin standard. The live/dead assay of clinical isolates strain demonstrated significant reduction of bacterial cells ∼67.52 folds compared to control group in 12 h. The hemolysis study suggested that CS-AuAg-NPs were non-hemolytic and safer for application in the wound. Furthermore, CS-AuAg-NPs were distributed in the CS film, which showed 87% wound recovery after 7 d in mice model. Hence, we concluded that CS-AuAg-NPs was safer and more effective against MDR bacteria and capable of skin regeneration in the infected wound.