Benoit Simard, Ph.D., and his colleagues started their nanoscale platform development effort with standard iron oxide nanoparticles. They then coated these particles with a layer of silica, and added a second layer of silica that also contained a fluorescent dye.
The net effect of adding these layers was three-fold. First, doubly coating the iron oxide nanoparticles improved the magnetic properties of the standard uncoated particles. Second, trapping the fluorescent dye in the second silica layer increased the stability of the dye when irradiated with bright light. Finally, the second silica layer provided a surface to which targeting and drug molecules could be attached easily.