Novel far-visible and near-infrared pH probes based on styrylcyanine for imaging intracellular pH in live cells

Abstract

Two novel vis-NIR pH probes based on styrylcyanine with acidic pH response are easily synthesized, which display large Stokes shift and high sensitivity. The significant colocalizations of two probes with LysoTracker Green DND-26 are achieved in C6 cells, suggesting potential application for imaging acidic organelles in live cells.

Design Strategies for Water-Soluble Small Molecular Chromogenic and Fluorogenic Probes

“…Compound 23, a styrylcyanine-based NIR pH probe with a pK a of 4.40 68 is fluorescent in acidic media but nonfluorescent in neutral environments. Results from confocal fluorescence microscopy showed that the probe has the potential for imaging acidic organelles in live cells.…”

A water-soluble pH fluorescence probe based on quaternary ammonium salt for bioanalytical applications

“…Currently, lots of novel fluorescence probes were reported based on the philosophy that the combination between the proton and the lone pair electrons within nitrogen, which could change the optical properties of fluorescent probes [33][34][35][36][37][38], besides that, pH-induced ring-opening reaction of the rhodamine is broadly used by varying the conjugated system [39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. Even though lots of rhodamine-based fluorescence probes have been widely applied in both solution and biosensing systems to discriminate the analytes from other biological abundant species so far, poor solubility of these probes in biological environments might result in decreased detection sensitivity, or even lose the response signal, which is a research bottleneck as regards progress in some areas of cell biology or medicine [55][56][57][58].…”

An indole-carbazole-based ratiometric emission pH fluorescent probe for imaging extreme acidity

“…So far, a number of excellent pH probes working for weak acidic organelles (such as lysosomes, pH 4.5-5.0) [7][8][9][10][11][12][13][14][15][16][17] or near neutral cytosol (pH 6. 8-7.4) [7,[18][19][20][21][22][23] have been exploited, and some are commercially available [7].…”