Luminescent Turn-On Upconversion Nanoprobes for Monitoring NADH In Vivo

Mitochondrial damage is implicated with a variety of pathological processes and is featured by the dramatically raised NADH level. To date, the detection and in situ imaging of NADH in living animals is still a challenge. Herein, we designed an upconversion luminescent nanoprobe for the in vivo imaging of NADH. The Nile blue (NB) with a strong absorption band at 500–700 nm can quench the red luminescence of the upconversion nanoparticle at 654 nm by the fluorescence resonance energy transfer effect. Under the presence of NADH, the NB was bleached, so that the fluorescence of the probe was "turned on". The nanoprobe achieved highly selective detection of NADH, and the in vivo monitoring of NADH was also demonstrated on living mice.