64Cu Radiopharmaceutical Chemistry

Copper-64, as a radionuclide, can be simultaneously used for both imaging and potential therapy, because of its specific nuclear characteristics, such as the half-life (12. 7 h) and decay properties (beta(+), 0. 653 MeV, 17. 8%; beta(-), 0. 579 MeV, 38. 4%). In the past two decades, with the well-established copper coordination chemistry, more and more novel ligands for copper-64 have been designed and synthesized, like DOTA, TETA, NOTA, CB-TE2A, C3B-DO2A, etc. Nowadays, copper-64 is able to bind not only with biologically relevant small molecules, but also with some antibodies, proteins, and nanoparticles. From another point of view, the stability of the copper-64-labeled radiopharmaceuticals has been significantly improved in both vitro and vivo tests. Thus, the exploration of novel ligands and receptors with new labeling strategies has become a hot issue in the copper radiopharmaceutical chemistry. Up to now, many new copper-64-labeled radiopharmaceuticals have been synthesized, some of which exhibit excellent biodistributions, as Cu-64-ATSM is an effective radiopharmaceutical in imaging of hypoxic tissues and Cu-64-PTSM is a good blood flow tracer, etc. This paper will selectively review some new labeling methods for copper-64-labeled radiopharmaceuticals, and some potential applications of these coordination compounds in both imaging and therapy. The perspectives of this field is addressed as well.