Surface Adsorption of the Alpha-Emitter Astatine-211 to Gold Nanoparticles Is Stable In Vivo and Potentially Useful in Radionuclide Therapy

Emanuel Sporer, Christian B. M. Poulie, Sture Lindegren, Emma Aneheim, Holger Jensen, Tom Bäck, Paul J. Kempen, Andreas Kjaer, Matthias M. Herth, Andreas I. Jensen*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Targeted α-therapy (TAT) can eradicate tumor metastases while limiting overall toxicity. One of the most promising α-particle emitters is astatine-211 (211At). However, 211At-carbon bonds are notoriously unstable in vivo and no chelators are available. This hampers its adoption in TAT. In this study, the stability of 211At on the surface of gold nanoparticles (AuNPs) was investigated. The employed AuNPs had sizes in the 25–50 nm range. Radiolabeling by non-specific surface-adsorption in >99% radiochemical yield was achieved by mixing 211At and AuNPs both before and after polyethylene glycol (PEG) coating. The resulting 211At-AuNPs were first challenged by harsh oxidation with sodium hypochlorite, removing roughly 50% of the attached 211At. Second, incubation in mouse serum followed by a customized stability test, showed a stability of >95% after 4 h in serum. This high stability was further confirmed in an in vivo study, with comparison to a control group of free 211At. The AuNP-associated 211At showed low uptake in stomach and thyroid, which are hallmark organs of uptake of free 211At, combined with long circulation and high liver and spleen uptake, consistent with nanoparticle biodistribution. These results support that gold surface-adsorbed 211At has high biological stability and is a potentially useful delivery system in TAT.
Original languageEnglish
JournalJournal of Nanotheranostics
Volume2
Issue number4
Pages (from-to)196-207
ISSN2624-845x
DOIs
Publication statusPublished - 2021

Keywords

  • Astatine-211
  • Targeted alpha-therapy
  • Gold nanoparticles
  • Radionuclides

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