Synthesis and characterization of fluorescent, radio-opaque, and paramagnetic silica nanoparticles for multimodal bioimaging applications

Monodisperse, fluorescent, radio-opaque and paramagnetic Ru(bpy):Gd III/SiO2 nanoparticles were developed using a water-in-oil (W/O) microemulsion system. The nanoparticle optical core was designed to isolate and protect the Ru(bpy) dye molecules from the outside environment to prevent photobleaching. Ru(bpy) molecules were doped inside the silica core during the synthesis process. Fluoroscopic images demonstrated that the nanoparticles were radio-opaque. The results show that the nanoparticle-synthesis strategy will allow doping of a wide-variety of fluorescent dye molecules and paramagnetic materials.