Copper-64-Alloyed Gold Nanoparticles for Cancer Imaging: Improved Radiolabel Stability and Diagnostic Accuracy

Gold nanoparticles, especially positron-emitter- labeled gold nanostructures, have gained steadily increasing attention in biomedical applications. Of the radionuclides used for nanoparticle positron emission tomography imaging, radiometals such as Cu-64 have been widely employed. Currently, radiolabeling through macrocyclic chelators is the most commonly used strategy. However, the radiolabel stability may be a limiting factor for further translational research. We report the integration of Cu-64 into the structures of gold nanoparticles. With this approach, the specific radioactivity of the alloyed gold nanoparticles could be freely and precisely controlled by the addition of the precursor (CuCl2)-Cu-64 to afford sensitive detection. The direct incorporation of Cu-64 into the lattice of the gold nanoparticle structure ensured the radiolabel stability for accurate localization invivo. The superior pharmacokinetic and positron emission tomography imaging capabilities demonstrate high passive tumor targeting and contrast ratios in a mouse breast cancer model, as well as the great potential of this unique alloyed nanostructure for preclinical and translational imaging.