Multifunctional Silver Nanoparticles: Synthesis and Applications

Multifunctional silver nanoparticles have attracted widely due to their potential applications. Based on the properties of individual silver nanoparticles, such as plasmonic and antibacterial properties, silver nanoparticles can become multifunctional by surface modifications with various surfactants or they can be combined in core-shell and composite structures with the magnetic nanoparticles to form bifunctional nanoparticles. After reviewing the methods of synthesis and applications of silver nanoparticles, the chapter describes the synthesis and the properties of the new types of multifunctional silver nanomaterials based on the plasmonic behaviors of silver nanoparticles and the iron oxide Fe3O4 superparamagnetic nanoparticles. One type is a simple combination of silver nanoparticles and iron oxide nanoparticles in a silica matrix Fe3O4/Ag-4ATP@SiO2. Other types are the core-shell structured nanoparticles, where Fe3O4 nanoparticles play as the core and silver nanoparticles are the outer shell, so-called Fe3O4@SiO2-Ag and Fe3O4-Ag. In the Fe3O4@SiO2-Ag, silver nanoparticles are reduced on the surface of silica-coated magnetic core, while in Fe3O4-Ag, silver nanoparticles are directly reduced on the amino groups functionalized on the surface of magnetic nanoparticles without coating with silica. Both of types of the multifunctional silver nanoparticles show the plasmonic and magnetic properties similar as the individual silver and iron oxide nanoparticles. Finally, some applications of those multifunctional silver nanoparticles will be discussed.