Dye-Assembled Upconversion Nanocomposite for Luminescence Ratiometric in Vivo Bioimaging of Copper Ions

Overdose of Cu²⁺ is associated with multiple diseases, such as Wilson disease, Parkinson disease, and Alzheimer disease. Therefore, detections of Cu²⁺ in vivo and in vitro are meaningful. Near-infrared fluorescent probes are commonly applied for the detection of Cu²⁺ in real time. With mono detection signal provided, these probes are not persuasive when applied to complicated biological environments, such as cells and animals. In this report, we conjugated the organic fluorescent probe CYDAC₁₆ with the UCNPs (lanthanide-doped upconversion nanoparticles) to develop a ratiometric luminescent probe for Cu²⁺. The composite material UCNPs-CYDAC₁₆ provides a ratiometric signal based on an upconversion luminescence 660 and 800 nm. With good sensitivity and selectivity for Cu²⁺, it works well in vivo and in vitro for the detection of Cu²⁺. We believe it is promising in further biological applications.