Gadolinium vanadate nanocrystals as carriers of α-emitters (225Ac, 227Th) and contrast agents

Abstract

Gadolinium vanadate (GdVO4) core and core + 2 shell nanocrystals (NCs) were evaluated for in vitro retention of 225Ac, 227Th, and their first decay daughters, 221Fr and 223Ra, respectively. GdVO4 NCs with a tetragonal crystal system (zircon-type) and spherical morphology were obtained by precipitation of GdCl3 and Na3VO4 using sodium citrate as a complexing agent. The growth of two nonradioactive GdVO4 shells on both Gd(225Ac)VO4 and Gd(227Th)VO4 core NCs was demonstrated by an increase of 0.7 nm and 2 nm in the crystallite size, respectively. The maximum leakage of 225Ac was 15% and 2.4% from core and core + 2 shells, whereas the leakage of 227Th was 3% and 1.5%, respectively. The presence of two nonradioactive GdVO4 shells increased the retention of 221Fr and 223Ra by 20% and 15% with respect to core NCs. Furthermore, a longitudinal proton relaxivity, r1 = 0.9289 s−1 mM−1, confirmed their potential application as contrast agents for magnetic resonance imaging. In summary, GdVO4 NCs show promising capabilities as radionuclide carriers with partial retention of decay daughters and as contrast agents for theranostic applications.

Trastuzumab Conjugated Superparamagnetic Iron Oxide Nanoparticles Labeled with 225Ac as a Perspective Tool for Combined α-Radioimmunotherapy and Magnetic Hyperthermia of HER2-Positive Breast Cancer

“…Various methods of attaching 225 Ac to biomolecules have been proposed. In addition to cyclic and linear ligands like DOTA, HEHA or DTPA, they were various types of nanoparticles like gadolinium vanadate nanocrystals [16], polymersomes [17], indium and lanthanum phosphates [18,19]. In our work as a carrier for 225 Ac, we proposed to use Superparamagnetic Iron Oxide-based Nanoparticles (SPIONs) where actinium similarly to lanthanides should be incorporated into their magnetic core [20].…”

Trastuzumab Modified Barium Ferrite Magnetic Nanoparticles Labeled with Radium-223: A New Potential Radiobioconjugate for Alpha Radioimmunotherapy

“…After developing the method for immobilization of 225 Ac inside lanthanides phosphate and vanadate nanoparticles [ 26 , 27 , 28 , 29 , 30 ], a team from the University of Missouri performed studies on the application of LnPO 4 nanoparticles to incorporate 223 Ra and 225 Ra [ 31 ]. The 223 Ra labeled LaPO 4 retained ~88% of the 223 Ra for 35 days, while, after covering of the core by two LaPO 4 layers, it decreased the release of 223 Ra and its decay products, 211 Pb, to 0.1%.…”

Nanoparticles in Targeted Alpha Therapy

“…Considering the intrinsic properties like luminescence and magnetic functionalities, the radionuclide retention capabilities, the small particle size (below 10 nm) and short time required for the synthesis (<1 h), Gd0.8Eu0.2VO4 core nanoparticles show great potential for medical applications, including α therapy. The same group proposed gadolinium vanadate nanocrystals (NCs) as carriers of 225 Ac and 227 Th radionuclides and contrast agents [91]. The synthesis of GdVO4 core and core +2 shell NCs with a tetragonal structure was performed using the same method as previously described [92].…”

“…The same group proposed gadolinium vanadate nanocrystals (NCs) as carriers of 225 Ac and 227 Th radionuclides and contrast agents [91]. The synthesis of GdVO 4 core and core +2 shell NCs with a tetragonal structure was performed using the same method as previously described [92].…”