Gold Nanoparticles Doped with ¹⁹⁹Au Atoms and Their Use for Targeted Cancer Imaging by SPECT

Gold nanoparticles have been labeled with various radionuclides and extensively explored for single photon emission computed tomography (SPECT) in the context of cancer diagnosis. The stability of most radiolabels, however, still needs to be improved for accurate detection of cancer biomarkers and thereby monitoring of tumor progression and metastasis. Here, the first synthesis of Au nanoparticles doped with ¹⁹⁹Au atoms for targeted SPECT tumor imaging in a mouse triple negative breast cancer (TNBC) model is reported. By directly incorporating ¹⁹⁹Au atoms into the crystal lattice of each Au nanoparticle, the stability of the radiolabel can be ensured. The synthetic procedure also allows for a precise control over both the radiochemistry and particle size. When conjugated with D-Ala1-peptide T-amide, the Au nanoparticles doped with ¹⁹⁹Au atoms can serve as a C-C chemokine receptor 5 (CCR5)-targeted nanoprobe for the sensitive and specific detection of both TNBC and its metastasis in a mouse tumor model. Radioactive Au nanoparticles doped with ¹⁹⁹Au atoms are conjugated with D-Ala1-peptide T-amide to serve as a CCR5-targeted nanoprobe for the sensitive and specific detection of both triple negative breast cancer and its metastasis in a mouse model by single photon emission computed tomography (SPECT).