Title: Overview on the production of radioactive nanoparticles for bioscience applications at the JRC Cyclotron
Publication Year: 2009
JRC N°: JRC53215
ISSN: 0362-4803
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC53215
Type: Articles in periodicals and books
Abstract: Nanomaterials are already used in many applications of science, medicine, and industry. Radioactive nanoparticles have the advantage that they can be accurately and precisely traced during each of the steps of their applications, thanks to the sensitivity of nuclear measurement techniques. There are already several protocols using radioactive nanoparticles, either for diagnosis or for therapeutic applications, combining the radioactivity (gamma or particle emitters) with the nanostructure in a single substance. In this paper, we give an overview of the scientific and technical activities devoted to the activation of nanoparticles. We have selected and investigated TiO2, Au, CeO2, Co, Ag, Re, Ho and C based nanomaterials. Experiments and Methods: Radioactive nanoparticles can be produced either by direct irradiation of the nanoparticles themselves or by using radioactive species as raw materials in the synthesis process. In this paper, we focus on the former production route. Direct irradiation can be performed with neutrons (in general in nuclear reactors) or with ion beams in particle accelerators (cyclotrons or LINACs). Neutron Activation: It has been observed that irradiations in nuclear reactors can damage the target nanostructure, especially if coated with organic material, due to the high gamma-radiation background. At the JRC Cyclotron, we have developed two neutron activators as an alternative to nuclear reactors for activation of nanoparticles to acceptable yields for cell/intracell uptake studies. The first activator is based on the Adiabatic Resonance Crossing concept. The neutrons are generated by protons bombarding a beryllium target. They are then slowed down in graphite and finally captured in the nanomaterial target. The second neutron activation methods is based on the thermalisation of the high neutron flux which is emitted during the daily commercial FDG production. The nanoparticles to be neutron activated are put in an appropriate neutron moderator and positioned close to the 18F target where they can be left to increasingly activate over several days. Charged Particle Activation: The JRC cyclotron (K=40) accelerates protons, deuterons, alphas or 3He2+ at variable energies. Neutron capture occurring in a nuclear reactor is comparable to the stripping reaction (d,p) in a cyclotron. In charged particles activation, therefore, nanoparticles/nanomaterials may be radiolabelled with a radioisotope of one of the target elements, though non-intrinsic radiolabels via (p,n) or other reactions may also be suitable. Results: Table 1 gives an overview on the results of the production of a variety of radioactive nanoparticles for nanobioscience applications carried out to date using either charged particle or neutron activations. Conclusion: Manufactured nanoparticles can be successfully radiolabelled by charged particles or neutrons in dedicated facilities developed for the purpose at the JRC Cyclotron. Sufficient nanoparticle activation yields have been achieved in the case of Au, CeO2 and TiO2 for subsequent in vitro biokinetic studies with different cell lines, and activation yields will be increased for other nanoparticle types for similar studies.
JRC Directorate:Institute for Health and Consumer Protection Historical Collection

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