A dual-site fluorescent probe for discriminately detecting low and high concentration of hypochlorite in living cells

Hypochlorite (ClO-) is an important bioactive molecule of living system which plays essential roles in many physiological and pathological processes. There is no doubt that the biological roles of ClO- depend highly on the concentration of ClO-. Unfortunately, the relationship between the concentration of ClO- and the biological process is unclear. Toward this purpose, in this work we addressed a core challenge for developing a powerful fluorescence tool for monitoring a wide concentration change (0-14 eq.) of ClO- via two distinct detection manners. The probe displayed fluorescence variation (red to green) upon addition of ClO- (0-4 eq.) and the color of test medium changed from red to colorless witnessed by the naked eyes. Surprisingly, in the presence of higher concentration of ClO- (4-14 eq.), the probe displayed another fluorescent signal change from green to blue. After demonstrating the excellent sensing properties of the probe with ClO- in vitro, it was successfully used to imaging different concentration of ClO- in living cells. We expected that the probe could act as an exciting chemistry tool for imaging of ClO- concentration-dependent oxidative stress event in biological system.