Design of a novel carrier for Dy-166/Ho-166 in vivo generator

We prepared ¹⁶⁶Dy labelled gold nanoparticles via a seed-mediated growth method. First, ¹⁶⁶Dy was co-reduced with a gold precursor to form a Dy-Au nanoparticle seed. Then an extra gold layer was grown on top of the seed nanoparticles to form a core-shell structured nanoparticle, i.e. DyAu@Au nanoparticle. The final product had a diameter of 5 nm and a ¹⁶⁶Dy labelling efficiency of 60 %. The ¹⁶⁶Ho retention tests showed that more than 95 % of ¹⁶⁶Ho was retained for at least 72 hours at 37℃ in water. To the best of our knowledge, this is the first study to retain radionuclides freed due to internal conversion with gold nanoparticles. Overall, this study presents a simple, quick, and chelator-free radiolabelling method for ¹⁶⁶Dy with minimum loss of internally converted ¹⁶⁶Ho.