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.