An endoplasmic reticulum-selective ratiometric fluorescent probe for imaging a copper pool

Hydrazide-linked naphthalimides undergo copper ion-selective hydrolysis with concomitant ratiometric fluorescence change. In addition, probe 1 is biocompatible and mainly localized to the endoplasmic reticulum (ER) in live HeLa cells. It thus can be used for imaging copper accumulation in the ER of live cells, as implied in copper-overloaded situations.