Ratio-tuned green-synthesized Ag–Fe bimetallic nanoparticles embedded in electrospun gelatin/chitosan nanofibrous scaffolds for antibacterial applications

Abstract

Wound and device-associated infections caused by drug-resistant microorganisms are a major global health problem, increasing morbidity, mortality and economic burden. Antimicrobial nanofibrous scaffolds have therefore gained attention as wound dressings capable of reducing infection risk. In this study, gelatin/chitosan (GEL/CTS) nanofibrous scaffolds incorporating silver–iron bimetallic nanoparticles (Ag–FeNPs) synthesized via a green route using Hypericum perforatum (H. perforatum) leaf extract were developed as potential antibacterial wound-dressing materials. Ag–FeNPs were produced at room temperature and characterized by different analytical techniques. Microstructural analysis confirmed that the biogenic nanoparticles were spherical, with an average size of 60.98 ± 18.09 nm, and were uniformly distributed throughout the GEL/CTS fibers. Ag–FeNPs with varying Ag : Fe ratios were subsequently embedded into the polymeric matrix to enhance scaffold wettability and antibacterial performance. FT-IR, XRD, FE-SEM, and water-contact-angle measurements demonstrated that incorporation of CTS and Ag–FeNPs reduced the fiber diameter (171.47 ± 55.96 nm) and improved hydrophilicity, with the GEL/CTS/Ag–Fe (2 : 1) formulation exhibiting the lowest WCA value (60.72°). Antibacterial assays conducted against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) revealed that the green-synthesized Ag–FeNPs were active against both strains, with stronger inhibition observed for E. coli. Among the nanofibrous scaffolds, the sample containing the highest Ag composition yielded the most pronounced reduction in bacterial colony formation. Overall, these findings indicate that GEL/CTS scaffolds reinforced with Ag–FeNPs possess favorable structural and biological properties, which highlighting their potential as effective antibacterial materials for applications such as wound dressings.