To test how well it worked, they turned to tiny zebrafish embryos, which are transparent for the first month of life and allow scientists to observe closely organ damage produced by cancer treatments. Zebrafish have most of their organs formed by the third day after fertilization.
They gave the embryos different doses of ionizing radiation as well as treatment by either Amifostine, which acted as a control agent, or CD60_DF1. First, they found that CD60_DF1 had almost no toxicity. Then, they saw that CD60_DF1 given before and even immediately after--up to 30 minutes--exposure to X-rays reduced organ damage by one-half to two-thirds, which was as good as the level of protection given by Amifostine.
"We also showed that the fullerene provided organ-specific protection," Dr. Dicker notes. "It protected the kidney from radiation-induced damage, for example, as well as certain parts of the nervous system."
He explains that one way that radiation frequently damages cells and tissues is by producing "reactive oxygen species"--oxygen radicals, peroxides and hydroxyls. The scientists showed that zebrafish embryos exposed to ionizing radiation had more than 50 percent reduction in the production of reactive oxygen species compared to untreated embryos.
Dr. Dicker says that the company has technology enabling certain molecules to be attached to the nanoparticles, which will allow for targeting to specific tissue and organs, further enhancing use of the nanoparticles.
Dr. Dicker and his team plan follow-up studies using mouse models that will allow them to find out whether fullerene protects the entire animal from radiation, and how it works to protect specific organs. They also are interested in exploring its ability to prevent long-term side effects of radiation, such as fibrosis.