Jeffery Zink, Ph.D., led a research team at the University of California, Los Angeles, that created the new nanoparticles, which contain an iron oxide nanoparticle core and a porous silica shell. The investigators coated the resulting nanoparticles with folic acid, a tumor targeting agent, and a fluorescent dye to enable optical imaging. Soaking the nanoparticles in a solvent containing either paclitaxel or camptothecin, both of which are poorly soluble in water and difficult to deliver to tumors as a result, resulted in significant drug loading through the pores in the silica shell. Tests showed that the drug-loaded nanoparticles were stable for at least 2 months.
Experiments with pancreatic cancer cells demonstrated that the targeted nanoparticles were taken up rapidly by cancer cells, whereas untargeted control nanoparticles were not. The researchers were able to quantify nanoparticle uptake using both MRI and optical spectroscopy thanks to the iron oxide nanoparticle core and fluorescent dyes, respectively. The targeted nanoparticles were also more toxic to the tumor cells than were untargeted nanoparticles.