α-Generator radionuclides are isotopes which undergo a radioactive decay, thus generating α particles and radioactive daughter products. Since α particles are highly cytotoxic, these isotopes have important applications for cancer treatment. However, a safe and efficient use of α-generator radionuclides necessitates a system able to deliver them to the target organ. Moreover, daughter products should be specifically retained in the pathological tissues.

To meet these requirements, Mark McLaughlin, University of Missouri, USA, and colleagues developed nanoparticles consisting of three concentric layers (pictured) The first one is an inner core containing the α-generator radionuclide ²²⁵Ac encapsulated into {La_0.5Gd_0.5}PO₄ nanoparticles. This layer is enclosed by a GdPO₄ shell which increases daughter products’ retention within the target tissues. Additionally, a gold shell guarantees the particles’ functionalization.

When injected into mice, the multi-shell nanoparticles delivered ²²⁵Ac and its daughter products to the target organ, with only minimal damage to non target tissues.

• Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy,
  M. F. McLaughlin, J. Woodward, R. A. Boll, J. S. Wall, A. J. Rondinone, S. J. Kennel, S. Mirzadeh, J. D. Robertson,
  PLoS ONE 2013, 8 (1), e54531.
  DOI: 10.1371/journal.pone.0054531