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Biothiols and SO 2 derivatives, as essential reactive sulfur species (RSS), play vital roles in various physiological processes and have a close network of generation and metabolic pathways among them. To clarify their complex correlations, fluorescent probes to simultaneously detect GSH, Cys, and SO 2 derivatives are highly desirable. Herein, we develop the first fluorescent probe ( BO-HEM ) to simultaneously discriminate GSH, Cys, and SO 2 derivatives. The fluorescent probe is designed by integration of hemicyanine and BODIPY fluorophores through an ether bond. The ether bond of the probe is rapidly replaced by thiolates through nucleophilic aromatic substitution (S N Ar) to generate hemicyanine with NIR fluorescence and sulfur-BODIPY . The amino groups of Cys but not GSH then further replace the thiolate to form amino-BODIPY . As for SO 3 2- , nucleophilic addition to the double bond of BO-HEM generates adduct O-BODIPY with green fluorescence. To further improve the sensing performance, the nanoprobe with increased reactivity and biocompatibility is constructed by encapsulation of BO-HEM into the polymeric micelle. More importantly, by taking advantage of the hydrophilicity of the reaction products, the spectral discrimination was further enhanced to avoid signal interference. The nanoprobe is applied to discriminate biothiols and SO 2 derivatives in living cells through three-color fluorescence imaging.

Nitric oxide (NO) and glutathione (GSH) have interplaying roles in oxidant-antioxidant balance. In this work, we developed the first example of a single fluorescent probe that displayed a turn-on fluorescence response toward NO and GSH from dual emission channels. The probe was synthesized by introducing 4-amino-3-(methylamino)-phenol to a BODIPY scaffold. Specifically, the NO-mediated transformation of diamine into a triazole triggered the fluorescence in the green channel, and the GSH-induced S N Ar substitution reaction led to the red-shifted emission in the red channel. The probe was successfully applied to detect the exogenous and endogenous NO and GSH in macrophage cells. More importantly, the probe revealed that NO induced by interferon-γ (IFN-γ), lipopolysaccharide (LPS), and l-arginine (l-Arg) could also elicit the augmentation of intracellular GSH. We anticipate the probe would hold great potential for investigating the redox balance in biological processes.

Glutathione (GSH) and cysteine (Cys) play different roles in biological systems, thus the discrimination between them is of great importance. Herein we report a multi-emissive fluorescent probe for the selective detection of GSH and Cys. The probe was composed of covalently linked BODIPY and coumarin fluorophores. The BODIPY fluorophore was designed to react with GSH and Cys and generate different products with distinct photophysical properties, and the coumarin fluorophore acted as an internal standard. The probe exhibited green emission in aqueous solution. Upon addition of Cys, it yielded nitrogen-substituted BODIPY with weak fluorescence and free coumarin with blue emission. In the presence of glutathione, it generated mono- and di-sulfur substituted BODIPY and coumarin, resulting in various emission colors at different concentrations of GSH. Interestingly, the solution exhibited white fluorescence at GSH concentration of 0.4mM. The probe was capable of detecting and imaging GSH and Cys in living HeLa cells, indicating its significant potential in biological applications., (Copyright © 2016 Elsevier B.V. All rights reserved.)

We report a fluorescent probe for the selective detection of mitochondrial glutathione (GSH). The probe, containing triphenylphosphine as a mitochondrial targeting group, exhibited ratiometric and selective detection of GSH over Cys/Hcy. The probe was used for imaging mitochondrial GSH in living HeLa cells.

Cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) are interconnected and play essential roles for regulating the redox balance of biological processes. However, finding a simple and effective method for the simultaneous determination for these three biothiols in biological systems is always a challenge. In this work, we report a method for the simultaneous quantitative determination of three biothiols in a mixture using a monochlorinated boron dipyrromethene (BODIPY)-based fluorometric sensor. At a specified period of time, after reacting with excess sensor, Hcy and GSH form predominantly sulfur-substituted BODIPY, while Cys generates sulfur-amino-diBODIPY due to a fast substitution-rearrangement-substitution reaction. A significant difference in polarities of these respective major products simplifies their separation by TLC, thus leading to the simultaneous determination of Cys, Hcy, and GSH readily. The sensor was successfully applied for the simultaneous quantitative detection of three biothiols in human serum, and the results were in good agreement with those obtained via high performance liquid chromatography (HPLC).

Biological thiols, including cysteine (Cys), homocystein (Hcy) and glutathione (GSH), play crucial roles in maintaining the appropriate redox status of biological systems. An abnormal level of biothiols is associated with different diseases, therefore, the discrimination between them is of great importance. Herein, we present two fluorescent sensors for selective detection of biothiols based on our recently reported intramolecular displacement mechanism. We expanded this mechanism to commercially available chromophores, 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) and heptamethine cyanine dye IR-780. The sensors operate by undergoing displacement of chloride by thiolate. The amino groups of Cys/Hcy further replace the thiolate to form amino-substituted products, which exhibit dramatically different photophysical properties compared to sulfur-substituted products from the reaction with GSH. NBD-Cl is highly selective towards Cys/Hcy and exhibits significant fluorescence enhancement. IR-780 showed a variation in its fluorescence ratio towards Cys over other thiols. Both of the sensors can be used for live-cell imaging of Cys. The wide applicability of the mechanism may provide a powerful tool for developing novel fluorescent sensors for selective detection of biothiols.

We report a turn-on fluorescent sensor based on nitrothiophenolate boron dipyrromethene (BODIPY) derivatives for the discrimination of cystein (Cys) from homocystein (Hcy) and glutathione (GSH). The sensor was applied for detection of Cys in living cells.

We report a ratiometric fluorescent sensor based on monochlorinated BODIPY for highly selective detection of glutathione (GSH) over cysteine (Cys)/homocysteine (Hcy). The chlorine of the monochlorinated BODIPY can be rapidly replaced by thiolates of biothiols through thiol-halogen nucleophilic substitution. The amino groups of Cys/Hcy but not GSH further replace the thiolate to form amino-substituted BODIPY. The significantly different photophysical properties of sulfur- and amino-substituted BODIPY enable the discrimination of GSH over Cys and Hcy. The sensor was applied for detection of GSH in living cells.

We report a fluorescent nanoprobe based on the co-assembly of amphiphilic BODIPY and fluorescein for selective detection of GSH. The amphiphilic BODIPY derivative, consisting of hydrophobic BODIPY unit and hydrophilic PEG chains, co-assembled with fluorescein to give non-fluorescent nanoparticles due to the aggregation caused quenching. Upon addition of GSH, the thiol group of GSH reacted with BODIPY through nucleophilic substitution to afford highly polar GSH-substituted BODIPY with high solubility in water, resulting in the disassembly of the nanoparticles. The GSH-induced disassembly of the nanoparticles released the highly fluorescent BODIPY derivative and fluorescein, enabling the dual-emissive detection of GSH. This nanoprobe was applied for the dual-channel fluorescence imaging of GSH in living cells. [ABSTRACT FROM AUTHOR]

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) remains unclear, making the diagnosis and treatment challenging. Cardiac oxidative and nitrative stress are strongly implicated in the pathogenesis of HFpEF. Herein, we present a unique three-channel fluorescent probe for evaluating cardiac oxidative and nitrative stress in HFpEF by simultaneous detection of NO and GSH. The probe exhibits a native green fluorescence (probe channel), while the presence of GSH and NO can sensitively turn the native green fluorescence into red fluorescence (GSH channel) and near-infrared fluorescence (NO channel), respectively. The probe clearly reveals that both GSH and NO levels are upregulated in cardiomyocytes and heart tissue with HFpEF. Moreover, it uncovers that the enhancement in NO and GSH levels are closely associated with increased level of iNOS (inducible nitric oxide synthase) and activation of the Keap1 (Kelch-like ECH-associated protein 1)/Nrf2 (nuclear factor erythroid 2–related factor 2)/ARE (antioxidant response element) signaling pathway in cardiomyocytes, respectively. This work proposes a promising approach for distinguishing normal heart and HFpEF heart by in vivo noninvasive imaging of both GSH and NO, and greatly contributing to the improvement of the diagnosis and treatment of HFpEF. [ABSTRACT FROM AUTHOR]