Direct Synthesis of Radioactive Gold Nanoparticles Using a Research Nuclear Reactor

We report the single-step synthesis of radioactive gold nanoparticles with an activity and size appropriate for potential use in cancer treatment and diagnosis. Methods: A solution of 2 mM gold chloride (HAuCl₄⋅3H₂O), 1 mM polyvinylpyrrolidone (molecular weight, 360,000), and 60 mM 2-propanol was prepared in deionized water. Seven different samples of the solution were irradiated in a neutron flux of 7.45 × 10¹² n/cm²⋅s in a research reactor for 0.5, 1, 3, 5, 10, 30, or 60 min. The resulting nanoparticles were characterized for morphology and chemical composition using a transmission electron microscope and ImageJ. Results: The obtained nanoparticles were 3-450 nm in size. The average size depended on the length of irradiation, with a longer irradiation producing smaller nanoparticles. Irradiation for 10 min produced nanoparticles with characteristics suitable for potential cancer treatment and diagnosis (average size, 50 nm; activity, 6.85 MBq/mL). Conclusion: Direct production of chemically stable radioactive gold nanoparticles was successfully accomplished using the Missouri University of Science and Technology reactor. The nanoparticles had physical and radioactive characteristics potentially useful for cancer treatment and diagnosis.