Ratiometric fluorescence monitoring of cerebral Cu²⁺ based on coumarin-labeled DNA coupled with the Cu²⁺-induced oxidation of o-phenylenediamine

A novel and facile ratiometric fluorescence method for evaluating Cu²⁺ has been developed based on coumarin-labeled single-stranded DNA (C-ssDNA) coupled with the Cu²⁺-induced oxidation of o-phenylenediamine (OPD). By combining the microdialysis technique, the ratiometric fluorescence method has also been successfully exploited to monitor the cerebral Cu²⁺ in the rat brain, promising new opportunities for studying the cerebral Cu²⁺-associated physiological and pathological events.