Multifunctional GdVO4:Eu core-shell nanoparticles containing Ac-225 for targeted alpha therapy and molecular imaging

Gadolinium vanadate nanoparticles (NPs) doped with europium, in concentrations between 5-40%, were synthesized via an aqueous route to prove their multimodal imaging functionalities and their performance as radionuclide carriers for targeted alpha therapy. Core-shell Gd0.8Eu0.2VO4 NPs were doped with the alpha-emitting actinium-225 to assess the in vitro retention of Ac-225 and its decay daughters; francium-221 and bismuth-213. Gd0.8Eu0.2VO4 core-shell NPs were obtained using a precipitation synthesis route having a tetragonal system, a spherical morphology, and a uniform particle size distribution. Gd0.8Eu0.2VO4 core-shell NPs displayed the characteristic intense emission at 618 nm (red) and paramagnetic behavior of Eu and Gd cations, respectively. Partial retention of radionuclides was obtained with Gd0.8Eu0.2VO4 core NPs, while deposition of two nonradioactive Gd0.8Eu0.2VO4 shells significantly decreased the leakage of both Ac-225 and Fr-221. The luminescence and magnetic functionalities as well as radionuclide retention capabilities of Gd0.8Eu0.2VO4 core-shell NPs demonstrate their potential for biomedical applications.