Antibacterial Activity of Gold and Silver Nanoparticles against Pathogen Species, E. coli and S. aureus

Abstract

Gold and silver nanoparticles (NPs) have been prepared by pulsed laser ablation in liquid (PLAL) operated at 532 nm wavelength with energy density about 17 J/cm2 and 10 J/cm2 for gold (Au) and silver (Ag), respectively, immersed in aqueous solvent with addition 5 mM sodium dodecyl sulfate (SDS) as surfactant. Transmission electron microscopy (TEM) revealed the spherical shape morphology of Ag nanoparticles and Au nanoparticles in the presence of surfactant and grain size of the Ag nanoparticles and Au nanoparticles was found to vary between 20 and 100 nm. Absorption spectra of Au and Ag colloidal confirmed the formation of nanoparticles and improve the addition of (SDS) as surfactant during PLAL method. Finally, the antibacterial activity of Au and Ag nanoparticles against bacterial species E. coli and S. aureus demonstrates that these nanoparticles were more active against Gram negative bacteria than Gram positive bacteria and this was attributed to change in the bacterial cell membranes composition.