(471e) Antibacterial Ag and Composite Ag-Fe3O4 Nanoparticles

There are many kinds of nano-sized antibacterial materials such as TiO2, ZnO, MgO, chitosan, copper and silver. Among them, nanocrystalline silver was proven to be the most effective antimicrobial agent, since silver and its compounds have powerful antimicrobial capability and broad inhibitory biocidal spectra for microbes including bacteria, viruses and eukaryotic microorganisms. Fe3O4 with strong magnetic properties and low toxicity can be heated to the elevated temperature in an external alternating magnetic field. The aim of the present work is synthesis of composite Ag-Fe3O4 nanoparticles stabilized in sodium citrate. Monodisperse silver-coated Fe3O4 nanoparticles were formed by reducing silver nitrate by the sodium citrate on the Fe3O4 nanoparticles surface. Thus bifunctional nanoparticles (average size 35 nm) having both superparamagnetic and antibacterial properties were synthesized. The evaluation of the combined effect of the antibacterial property of the silver and inductive heating property of the magnetite is presented. Several methods for antibacterial tests on gram-negative bacteria E.coli are well-tried and described their activity. The comparative study between single silver nanoparticles and composite silver-magnetite nanoparticles is described. Both particle size and shape were evaluated by means of transmission electron microscopy. It was found that the bactericidal effect of composite Ag-Fe3O4 particles was superior to pure Ag particles both absolutely and when related to the unit mass of silver.