A novel pH probe based on a rhodamine–rhodamine platform

Abstract

A novel pH probe based on rhodamine–rhodanine platform.

A ratiometric lysosomal pH probe based on the coumarin–rhodamine FRET system

“…Inspired by the previous work, herein we present a coumarin-rhodamine FRET system as a ratiometric pH probe (RC1). Compared with other probes we reported, RC1 possesses ratiometric properties 16,26,29,30,57 and simpler structure 18 and the emission spectrums of coumarin and rhodamine are well separated. Furthermore, RC1 responds to pH fluctuations within a wider pH range (4.20-6.00), 17 so the probe has greater potential for biological application.…”

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

“…For one thing, the weakly basic substances can cause an increase of lysosomal pH by leaking protons out of lysosomes, for another, the concentration of chloroquine required to cause such effect is considerably lower than that of other weak bases [67]. In this study, the fluorescence intensities within the cells were gradually weakened accompanied with increased concentration of chloroquine from 0 to 20 lM, which exhibited the well performance of REI as an indicator in the monitoring pH changes of lysosomal in living cells with faster response and more significant results compared with other rhodamine-based pH fluorescence probes [39,65] (Fig. 5).…”

“…A good reversibility of the probe toward pH enabled us to propose a mechanism for the equilibrium of probe REI between pH = 4.2 and pH = 7.2 (Scheme 1). A possible interaction between probe REI and H + is also suitable for the similar phenomenon of other pH probes with the same functional fluorophore as probe REI [39,59,65,66].…”

“…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].…”

Two rhodamine lactam modulated lysosome-targetable fluorescence probes for sensitively and selectively monitoring subcellular organelle pH change

“…The investigation of the spatial-temporal distribution of pH and its fluctuations in lysosomes, especially those in cancer cells, provides a strategic approach to visualize the early development of tumor tissue [8]. It is obvious that exploring simple and convenient ways to study the lysosomal lumen of cancer cells is desirable for cancer research [9][10][11][12].…”