Abstract
Introduction. Targeted alpha therapy (TAT) has the potential for killing specific tumor cells with minimum collateral damage to surrounding healthy tissue. Radionuclides such as 223Ra, 225Ra, and 225Ac are of special interest for radiotherapeutic applications as they emit multiple α-particles during their decay. Utilizing appropriate carriers capable of retaining both the parent radioisotope as well as daughter products is important for the effective delivery of the radioisotope to the tumor site while mitigating global in vivo radiotoxicity.
Methods. In this work, core and core+2 shells (NPs with 2 additional layers of cold LaPO4 deposited on the core surfaces) LaPO4 nanoparticles (NPs) were synthesized containing either 223Ra or 225Ra/225Ac and the retention of the parents and daughters within the NPs in vitro was investigated.
Results. The NPs crystallized in rhabdophane phase with mean diameters of 3.4 and 6.3 nm for core and core+2 shells, respectively. The core LaPO¬4 NPs retained up to 88% of 223Ra over 35 days. However, in the core+2 shell NPs, the retention of 223Ra and its daughter, 211Pb, was improved to > 99.9% over 27 days. Additionally, the retention of 225Ra/225Ac parents was > 99.98% and ~80% for the 221Fr and 213Bi daughters over 35 days for the core+2 shell NPs.
Conclusions. These results suggest that LaPO4 NPs are potentially effective carriers of radium isotopes.
