Gold nanoparticles as efficient antimicrobial agents for Escherichia coli and Salmonella typhi

Gold nanoparticles were supported onto clinoptilolite, mordenite and faujasite zeolites. Content of gold in materials varied between 2.3 and 2.8 wt%. The size, dispersion and roughness of gold nanoparticles were highly dependent of the zeolite support. The faujasite support was the support where the 5 nm nanoparticles were highly dispersed. The efficiency of gold-zeolites as bactericides of Escherichia coli and Salmonella typhi was determined by the zeolite support.Gold nanoparticles dispersed on zeolites eliminate Escherichia coli and Salmonella typhi at short times. The biocidal properties of gold nanoparticles are influenced by the type of support which, indeed, drives key parameters as the size and roughness of nanoparticles. The more actives materials were pointed out Au-faujasite. These materials contained particles sized 5 nm at surface and eliminate 90–95% of Escherichia coli and Salmonella typhi colonies.There is an increasing interest in materials holding antimicrobial properties because in several fields the use of these materials is mandatory, e.g. in medicine [1-3]. The most common antimicrobial compounds are benzalkonium chloride, triclosan and silver [4-6] although other heavy metals are also used. Some antimicrobials incorporated to other materials have been applied as adhesives [7], window cleaners [8], textiles, and wallpaper gloves [9], among others.The silver as antimicrobial has been used mainly as ion Ag + and also different delivery systems that release silver ions in a variety of concentrations have been explored [10,11]. Furthermore, the efficiency of metallic Ag particles to inhibit the growth of bacteria has been also reported. These particles are proposed as an alternative to materials with a silver ion release system because of the large variables that determine the release of ions and also because ions are reactive in several media, for instance they are solvated or coordinated to other ions easily. Thus, metallic silver has been incorp