On demand release of ionic silver from gold-silver alloy nanoparticles: fundamental antibacterial mechanisms study

Abstract Synthesis and biomedical research of bimetallic gold-silver nanoparticles (Au–Ag NPs) have gained much attention due to their unique properties. Antibacterial mechanism of gold-silver nanoparticles is a current topic of interest in nanomedicine engineering. We used three routes in the synthesis of Au–Ag NPs alloy: i) Co-reduction of [HOOC-4-C6H4N N]AuCl4/AgNO3, ii) Seeding of AuNPs-COOH/AgNO3 and iii) immobilization of AgNPs over the parent AuNPs-COOH. Two mild reducing agents, NaBH4 and 9-BBN (9-borabicyclo(3.3.1)nonane), were used. Colloidal alloy nanoparticles structure was confirmed using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The particles reduced using NaBH4 were larger (~20 nm) than those synthesized using 9-BBN (