RT Journal Article SR Electronic T1 Encapsulation of α-Particle–Emitting 225Ac3+ Ions Within Carbon Nanotubes JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 897 OP 900 DO 10.2967/jnumed.115.158311 VO 56 IS 6 A1 Michael L. Matson A1 Carlos H. Villa A1 Jeyarama S. Ananta A1 Justin J. Law A1 David A. Scheinberg A1 Lon J. Wilson YR 2015 UL http://jnm.snmjournals.org/content/56/6/897.abstract AB 225Ac3+ is a generator of α-particle–emitting radionuclides with 4 net α-particle decays that can be used therapeutically. Targeting 225Ac3+ by use of ligands conjugated to traditional bifunctional chelates limits the amount of 225Ac3+ that can be delivered. Ultrashort, single-walled carbon nanotubes (US-tubes), previously demonstrated as sequestering agents of trivalent lanthanide ions and small molecules, also successfully incorporate 225Ac3+. Methods: Aqueous loading of both 225Ac3+ ions and Gd3+ ions via bath sonication was used to construct 225Ac@gadonanotubes (225Ac@GNTs). The 225Ac@GNTs were subsequently challenged with heat, time, and human serum. Results: US-tubes internally loaded with both 225Ac3+ ions and Gd3+ ions show 2 distinct populations of 225Ac3+ ions: one rapidly lost in human serum and one that remains bound to the US-tubes despite additional challenge with heat, time, and serum. The presence of the latter population depended on cosequestration of Gd3+ and 225Ac3+ ions. Conclusion: US-tubes successfully sequester 225Ac3+ ions in the presence of Gd3+ ions and retain them after a human serum challenge, rendering 225Ac@GNTs candidates for radioimmunotherapy for delivery of 225Ac3+ ions at higher concentrations than is currently possible for traditional ligand carriers.