A colorimetric and ratiometric fluorescent probe for ClO targeting in mitochondria and its application in vivo.

A colorimetric and ratiometric fluorescent probe PMN-TPP for imaging mitochondrial ClO was prepared. The selectivity of PMN-TPP was excellent and the detection would not be influenced by other ROS. The limit of detection (LOD = 3σ/slope) for ClO was evaluated to be 0.43 μM, suggesting the probe's high sensitivity to ClO. For the biological applications, PMN-TPP performed well in detecting endogenous HClO in living RAW264.7 macrophage cells. A co-localization study employing Mito Tracker green revealed that PMN-TPP was specifically located in the mitochondria of living RAW264.7 macrophage cells. In the in vivo experiment, a nude mouse with acute inflammation stimulated by lipopolysaccharide (LPS) was employed. After injection of PMN-TPP, the fluorescence signal changed gradually in 30 min and then remained unchanged in the injection region, demonstrating that PMN-TPP could detect the endogenous HClO in living animals.