Rhodamine B thiohydrazide (RBS) was firstly employed as turn-on fluorescent probe for hypochlorite in aqueous solution and living cells. It exhibits a stable response to hypochlorite from 1.0×10-6to 1.0×10-5M with a detection limit of 3.3×10-7M. The response of this probe to hypochlorite is fast and highly selective compared with other reactive oxygen species (such as.OH,1O2, H2O2) and other common anions (such as X-, ClO2-, ClO4-, NO3-, NO2-, OH-, Ac-, CO32-, SO42-).
We reported here a turn-on fluorescent probe (1) for the detection of cysteine (Cys) by incorporating the recognition unit of 2,4-dinitrobenzenesulfonyl ester (DNBS) to a coumarin derivative. The structure of the obtained probe was confirmed by NMR and HRMS techniques. The probe shows a remarkable fluorescence off-on response (∼52-fold) by the reaction with Cys in 100% aqueous buffer. The sensing mechanism was verified by the HPLC test. Probe 1 also displays high selectivity towards Cys. The detection limit was calculated to be 23 nM. Moreover, cellular experiments demonstrated that the probe is highly biocompatible and can be used for monitoring intracellular Cys.
A ratiometric fluorescent probe CRSH based on a FRET platform for detecting HOCl. CRSH showed high selectivity, excellent sensitivity and a fast response toward HOCl.
A new benzimidazole-hemicyanine-based ratiometric fluorescent probe (ZBM-H) was developed, which showed high selectivity and sensitivity for detecting HClO.
A Schiff base fluorescent probe, namely naphthalic anhydride – (2-pyridine) hydrazone (NAH), has been synthesized and developed for the highly selective and sensitive monitoring of Fe3+ ions in an aqueous solution and living cells.
A highly selective OFF–ON fluorescent probe is developed for the sensing of Cu2+ based on the hydrolysis of a quinoline-2-carboxylate moiety. The probe is weakly fluorescent due to esterification of the phenolic group. Upon treatment with 1 equiv. of Cu2+, the probe exhibits strong fluorescence at 570 nm. The probe also exhibits high selectivity for Cu2+ over other cations with a low detection limit of 0.2 μM, which is sensitive enough to meet the standard of the World Health Organization for Cu2+ in drinking water (30 μM). Moreover, the probe shows a very low cell cytotoxicity, and imaging experiments demonstrate that the probe can be used for the sensing of Cu2+ in living cells.
A Turn-On Fluorescent Probe for Sensitive Detection of Cysteine in a Fully Aqueous Environment and in Living Cells