Synthesis and targeting of gold-coated 177Lu-containing lanthanide phosphate nanoparticles-A potential theranostic agent for pulmonary metastatic disease.

Targeted radiotherapies maximize cytotoxicity to cancer cells. In this work, we describe the synthesis, characterization, and biodistribution of antibody conjugated gold-coated lanthanide phosphate nanoparticles containing 177Lu. [177Lu]Lu0.5Gd0.5(PO4)@Au@PEG800@Ab nanoparticles combine the radiation resistance of crystalline lanthanide phosphate for stability, the magnetic properties of gadolinium for facile separations, and a gold coating that can be readily functionalized for the attachment of targeting moieties. In contrast to current targeted radiotherapeutic pharmaceuticals, the nanoparticle-antibody conjugate can target and deliver multiple beta radiations to a single biologically relevant receptor. Up to 95% of the injected dose was delivered to the lungs using the monoclonal antibody mAb-201b to target the nanoparticles to thrombomodulin receptors. The 208 keV gamma ray from 177Lu decay (11%) can be used for SPECT imaging of the radiotherapeutic agent, while the moderate energy beta emitted in the decay can be highly effective in treating metastatic disease.