Gold-coated silver nanoplates, when subjected to pulsed laser irradiation, changed their shape from triangular to spherical, accompanied by a shift of their extinction spectra. The simple single crystal structure of the silver nanoplates changed to multiple small crystal domains. The ratio of silver to gold of the particles also changed from 22 : 1 to 4.5 : 1, enabling more silver to be released. As a result, the antibacterial activity of the gold-coated silver nanoplates was significantly increased after pulsed laser irradiation.

Silver nanoparticles are known to have strong antibacterial activity and constitute a novel material to treat infectious diseases caused by pathogenic bacteria. The antimicrobial activity of silver nanoparticles is influenced by two important factors, their high dispersion stability and their release of silver ions. In this study, silver nanoparticles were treated with gold ions. The resultant Ag/Au nanoparticles were a hollow-shaped alloy made of silver and gold atoms. The antibacterial activity of the Ag/Au nanoparticles against the pathogenic bacteria S. Typhimurium was stronger than the original silver nanoparticles. Additionally, the release of silver ions from the hollowed Ag/Au nanoparticles was higher than the original silver nanoparticles. The existence of gold atoms on the silver metal and chloride ions in the medium likely enhanced the release of silver ions from the nanoparticles. The gold treatment of silver nanoparticles is an effective method to improve their antimicrobial activity.

No abstract

No abstract