Sustainable synthesis of bimetallic Cu–Ag nanoparticles using waste-derived chitosan and citrus extract: a green approach to combat antimicrobial resistance

) and a strain-corrected crystallite size of 51.7 nm, consistent with TEM. Antimicrobial assays against Escherichia coli O157:H7 and Staphylococcus aureus showed inhibition zones of 26.33 ± 0.58 mm and 22.50 ± 0.50 mm, with minimum inhibitory concentrations of 0.156-0.312 mg/mL. This work demonstrates the potential of integrated waste-to-nanomaterial strategies for antimicrobial applications, highlighting the need for mechanistic studies, biocompatibility assessment, and scale-up evaluation.