Anear-infrared ratiometric fluorescent probe for cysteine detection overglutathione indicating mitochondrial oxidative stress in vivo

We establish anear-infrared (NIR) ratiometric fluorescent probe Cy-NB for the selectivedetection of cysteine (Cys) over glutathione (GSH) and homocysteine (Hcy) inmitochondria to indicate oxidative stress. Heptamethine cyanine dye is chosenas the fluorophore of Cy-NB whose emission locates in NIR region. Andp-nitrobenzoyl is employed as the fluorescent modulator due to its capabilityof selective-Cys response. Once triggered by Cys, the uncaged p-nitrobenzoylrearranges the polymethine π-electron system of the fluorophore, which leads toa remarkable spectrum shifts in absorption and emission profiles. Takingadvantage of these spectroscopic properties, we construct a ratiometricfluorescent signal for the detection of Cys with a detection limit of 0.2 µMwithin 5 min. Our probe Cy-NB can sensitively detect the mitochondrial Cyspool changes under different oxidative stress status in HepG2 cells. We alsosuccessfully employ Cy-NB to imaging Cys level changes in living mice. Itsuggests that mitochondrial Cys can be used as an oxidative stress biomarkerwith simple potential clinical applications. And our probe Cy-NB is of greatpotential for further utilizing in exploring the physiological function of Cysin biological systems.

A near-infrared ratiometricfluorescent probe for cysteine detection over glutathione indicatingmitochondrial oxidative stress in vivo

Kun Yin, Fabiao Yu,* Weiwei Zhang, LingxinChen*

Biosensors and Bioelectronics

Volume 74, 15 December 2015, Pages 156–164

http://www.sciencedirect.com/science/article/pii/S0956566315302074