Fabrication of antibacterial monodispersed Ag–SiO2 core–shell nanoparticles with high concentration

Abstract Monodispersed Ag–SiO 2 core–shell nanoparticles with a high concentration of 400 mg/L were successfully fabricated by using tetraethoxysilane as silica precursor and reducing silver nitrate with ascorbic acid in the presence of cetyltrimethylammonium bromide as stabilizing agent. The nanoparticles had a spherical silver core in a size range from 14–26 nm in diameter and an amorphous silica shell of 15–28 nm thickness, respectively. The antibacterial effects of Ag–SiO 2 core–shell particles against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) were tested by the usual twofold serial dilution method for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The results indicated that the core–shell nanoparticles owned excellent antibacterial effects.