Sensitive and selective off-on rhodamine hydrazide fluorescent chemosensor for hypochlorous acid detection and bioimaging.

A rhodamine 6G hydrazide fluorescent chemosensor was prepared for the rapid HOCl detection in aqueous media. The system makes good use of the irreversible HOCl-mediated selective oxidation reaction to generate fluorescent response proportional to the amount of HOCl in neutral buffer. This probe exhibits great photostability, high sensitivity, and good selectivity for HOCl over other reactive species and most of the common metal ions. Furthermore, the probe is cell membrane permeable, and its applicability has been successfully demonstrated for fluorescence imaging of both exogenous and endogenous HOCl within living cells. Cytotoxicity assays prove that this probe is almost nontoxic to the cultured cell lines under the experimental conditions.