Development of polyethylene glycol-modified gold nanoparticles for the delivery of Lutetium-177-radiopharmaceuticals based on antibodies

Lutetium-177-labeled radiopharmaceuticals have been used clinically for the treatment of various malignancies in nuclear medicine. The main characteristics of lutetium-177 (177Lu), such as its concurrent emission of imageable gamma photons (208 key (11 %) and 113 key (6.4 %)) as well as therapeutic beta- emission [beta(max) = 497 key] make it one of the radionuclides of choice to treat various types of cancers. In general, for therapeutic purposes, the synthesis of [177Lu]Lu-labeled radiopharmaceuticals requires high specific activity of 177 Lu which can be produced by a nuclear reactor with high neutron flux. Unfortunately, only a few countries have benefited from this type of reactor. The use of low specific activity of 177 Lu will lead to a low loading of this radionuclide in cancer cells, and thus decrease its efficacy. Accordingly, recent efforts have been made to explore suitable drug delivery vehicles to improve the 177 Lu loading in targeted cancers. Due to their remarkable size and suitable surface properties, gold nanoparticles (AuNPs) have attracted attention among scientists as suitable vehicles to carry a high amount of drugs to targeted diseases. Hence, the presence of AuNP in a [177Lu]Lu-labeled radio- pharmaceutical complex increases the amount of 177 Lu. Overall, delivering sufficient radioactivity of 177 Lu to cancer cells is very critical, which can be realized by conjugating the [177Lu]Lu-complex with AuNPs. This review summarizes recent advances in the development of AuNPs and discusses their potential as a drug vehicle in delivering substantial therapeutic radionuclide 177 Lu into cancerous tissues.