and a silica core has been developed. The approach utilizes positively charged amino-
modified SiO2 particles as templates for the assembly of negatively charged 15 nm
superparamagnetic water-soluble Fe3O4 nanoparticles. The SiO2− Fe3O4 particles
electrostatically attract 1− 3 nm Au nanoparticle seeds that act in a subsequent step as
nucleation sites for the formation of a continuous gold shell around the SiO2− Fe3O4 …