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Updated: Apr 30, 2026

Measuring Phagosome pH by Ratiometric Fluorescence Microscopy
Published on: December 7, 2015
Fluorescent push-pull pH-responsive probes for ratiometric detection of intracellular pH
Martin Ipuy1, Cyrielle Billon, Guillaume Micouin
1Laboratoire de Chimie de l'ENS de Lyon, CNRS UMR 5182, Ecole Normale Supérieure de Lyon, Université Lyon I, 46 allée d'Italie, 69364 Lyon cedex 07, France. yann.bretonniere@ens-lyon.fr.
Abstract:
A family of fluorescent push-pull pH-responsive probes based on 2-dicyanomethylidene-3-cyano-4,5,5-trimethyl-2,5-dihydrofuran as a strong electron acceptor group is described. Small structural variations allow obtaining pK(a) ranging from 4.8 to 8.6, underlining the role of the substituent in modulating the acidic properties. Remarkable changes in the optical properties (in particular the fluorescence intensity ratios) were observed as a function of pH. The most interesting probes with pK(a) close to neutrality were used for ratiometric imaging of intracellular pH.
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