The organelle-specific pH is crucial for cell homeostasis. Aberrant pH of lysosomes has been manifested in myriad diseases. To probe lysosome responses to cell stress, we herein report the detection of lysosomal pH changes with a dual colored probe (CM-ROX), featuring a coumarin domain with "always-on" blue fluorescence and a rhodamine-lactam domain activatable to lysosomal acidity to give red fluorescence. With sensitive ratiometric signals upon subtle pH changes, CM-ROX enables discernment of lysosomal pH changes in cells undergoing autophagy, cell death, and viral infection.

A visual and fluorogenic detection method for a nerve agent simulant was developed based on a Lossen rearrangement of rhodamine-hydroxamate, in the presence of diethyl chlorophosphate, under alkaline conditions.

A hetero-organelle partition and lysosome activable sensor was developed for fluorogenic detection of mitochondrial depolarization in autophagy and cell death.

Determination of nitrite levels is of substantial interest in many applications from monitoring drinking water quality to clinical diagnosis, etc. N-(Rhodamine B)-lactam-o-phenylenediamine (RB-PDA) was identified from a panel of rhodamine-lactams for fluorogenic and visual detection of nitrite in aqueous media via analyte triggered formation of highly fluorescent and deep colored species.NSFC [21072162]; Natural Science Foundation of Fujian Province of China [2011J06004]; Fundamental Research Funds for the Central Universities [2011121020]; NEFTBS [J1030415

A chromogenic and fluorogenic detection of aldehydes was achieved via analyte triggered opening of the deoxylactam of N-(rhodamine B)-deoxylactam-ethylenediamine (dRB-EDA). The utility of the sensor was demonstrated by fluorescent labeling of aldehyde-displaying sialoproteins on cell surfaces.