Synthesis of radioactive and nonradioactive nanostructures through radiolytic and wet chemistry

by Jessika Viviana Rojas Marin

Institution: Missouri University of Science and Technology
Year: 2014
Keywords: Metallic Nanoparticles; Radiation Induced Chemistry; Targeted Alpha Therapy
Record ID: 2026655
Full text PDF: http://hdl.handle.net/10355/43419


"In this work the synthesis of non radioactive and radioactive nanoparticles (NPs) through radiolytic and wet chemistry was studied. Non radioactive NPs of rhenium, iridium, and rhodium were synthesized from aqueous solutions containing the metal salt precursors by gamma irradiation. The solutions were irradiated to generate reducing species that led to the nucleation and growth of the nanoparticles. Amorphous rhenium oxide nanoparticles with average sizes ranging from 10 nm to 55 nm were obtained. Metallic iridium and rhodium nanoparticles were produced in polyvinyl-pyrrolidone (PVP) having narrow particle size distributions and average particle sizes from 2 nm to 6 nm. The stability of the NPs in PVP was explained based on the interaction of the metal with both of the functional groups, C-N and C=O, of the PVP. Iridium NPs supported on carbon nanotubes were also synthesized by gamma irradiation. The NPs were finely distributed on the surface of the nanotubes. The nanoparticle yield was found to increase with the radiation dose and the precursor concentration. The synthesis of radioactive NPs, specifically lanthanum phosphate containing ²²³Ra and ²²⁵Ra isotopes, was carried out in aqueous media using a precipitation method. The NPs crystallized in rhabdophane structure with a mean particle size of 3.4 nm and 6.3 nm for core and core-2 shells respectively. The ability of LaPO₄ NPs to retain the isotopes within their structure was investigated. It was found that core NPs retained up to 88% of the activity over a period of 35 days. It was also found that the addition of two LaPO₄ shells to the core NPs increases the retention ability up to 99.99%. This fact suggests that LaPO₄ NPs are potential carriers of radium isotopes for targeted alpha therapy." – Abstract, page iv.