A mitochondria-targeted fluorescent probe for fast detecting hypochlorite in living cells

A fast-responsive fluorescent probe PI-Py was designed and synthesized for sensitive and selective detecting hypochlorite (ClO-). The probe PI-Py was intrinsically non-fluorescent due to the PET effect of the phenothiazine moiety. After reacting with ClO-, the PET effect was blocked, and a strong green emission of the BODIPY unit was recovered. The probe PI-Py showed an excellent selectivity towards ClO- in comparison of other ROS. The limit of detection for ClO- was calculated to be 1.7 nM, proving the probe's high sensitivity. Moreover, the probe PI-Py has been proved to be effective in visualizing the variations of exogenous ClO- in living HeLa cells. A colocalization study employing Mito Tracker red reveals that the PI-Py is specifically located in the mitochondria.