Development and optimization of functionalized gold-198 nanoparticles for use in cancer therapy

Gold nanoparticles (AuNPs) have multifaceted applications in imaging, diagnostics, and as drug delivery agents. Coating AuNPs in natural products such as nutraceuticals increases the biomedical applications by imparting anti-inflammatory, anti-oxidant, and anti-cancer properties; moreover, the inclusion of the radioisotope gold-198 (t½ = 2.7 d, E_βmax = 0.96 MeV, Eγ = 411 keV) can convert functionalized AuNPs into radiotherapeutic agents. However, synthetic routes to AuNPs are not amenable to radiochemical synthesis because they require excess gold, long synthesis times, and large waste volumes. The objective of this study was to develop and optimize a route to ¹⁹⁸AuNPs functionalized with various organic coatings. A procedure was developed that enabled the synthesis to be completed in less than 3 h, with a radiochemical yield of >99%. The method validation will be presented, along with stability studies of the ¹⁹⁸AuNPs at physiological appropriate pH, and next steps toward translating these nanoparticles into a cancer therapeutic. (author)