A BODIPY-derived fluorescent probe for cellular pH measurements

In this study, BODIPY-appended calix[4]arene was chosen as a fluorescent probe for intracellular pH. The compound with cell permeability can monitor the minor pH change near neutrality inside the cell and is the first BODIPY-derived probe reported for cytosolic pH. Owing to a high level of cell retention and minor cytotoxicity of the probe, stable fluorescence is provided in the cells for 24 h, facilitating the precise observation of intracellular pH. A model of cell apoptosis was designed by exposure of the cells to a low concentration of hydrogen peroxide. An increase in the fluorescence of the cells confirmed that BODIPY-appended calix[4]arene sensed the fluctuation of the cellular pH during early cell apoptosis. The developed fluorescent pH probe will be useful for the study of cell apoptosis. (c) 2013 Elsevier Inc. All rights reserved.