Cu²⁺-labeled dansyl compounds as fluorescent and PET probes for imaging apoptosis

Compound DNSTT-Cu²⁺, a novel chelate of Cu²⁺ with DOTA conjugated to a fluorescent dansyl fragment, is developed for imaging cell apoptosis. Apoptotic U-87MG cells could be selectively visualized by the fluorescence of DNSTT-Cu²⁺ from cytoplasm of cells, confirmed by the fluorescence of apoptosis cells co-labeled with Alexa Fluor 568-labeled annexin V, a conventional probe for selectively labeling membranes of apoptosis cells. A radioactive ⁶⁴Cu²⁺ analog, DNSTT-⁶⁴Cu²⁺, was easily synthesized, providing a potential PET probe for imaging apoptosis in vivo.