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Hydrogen sulfide (H 2 S) is a vital gas signaling molecule that performs crucial physiological functions in biological systems, and it can also cause food safety problems. In this study, we developed a cyanine derivative-based mitochondrial-targeted near-infrared fluorescent probe PC-H 2 S for detecting H 2 S. When PC-H 2 S reacted with H 2 S, it reached maximum fluorescence intensity at 656 nm and detection limit as low as 34 nM, and exhibited strong chromogenic response from green to red for H 2 S. Moreover, PC-H 2 S could be utilized to identify H 2 S generated during food spoilage and thus monitored the process of food spoilage. More significantly, PC-H 2 S showed excellent mitochondrial targeting capabilities and endogenous/exogenous H 2 S imaging of living cells and zebrafish could be performed. As a result, this research provides an attractive method for detecting H 2 S in food and biological systems and has potential value in physiopathological research. [Display omitted] • A cyanine derivative-based mitochondrial-targeted NIR fluorescent probe PC-H 2 S for detecting H 2 S was developed. • PC-H 2 S had a low detection limit and exhibited strong chromogenic response from green to red for H 2 S in naked eyes and UV light. • PC-H 2 S test strips was capable of monitoring H 2 S produced by food spoilage. • PC-H 2 S could be used for living cells and zebrafish imaging. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) is an important endogenous gasotransmitter and has been implicated with a variety of biological processes. The development of an efficient method for monitor H 2 S fluctuations in biological systems is of great significance to understand its roles in physiological and pathological conditions. In this work, two red-emitting fluorescent probes SNARF-SSPy and SNARF-SeSPy for H 2 S detection with turn-on fluorescence signals were reported. Interestingly, SNARF-SeSPy exhibited excellent anti-interference via dual selenium-sulfur exchange reaction even in the presence of high concentrations of thiols, whereas SNARF-SSPy did not sense H 2 S in the same condition. Additionally, in the present of H 2 S, SNARF-SeSPy showed a rapid response and excellent sensitivity with a detection limit of 34 nM. Most importantly, SNARF-SeSPy featured low cytotoxicity and could be employed to detect and image exogenous/endogenous H 2 S in living cells and zebrafish. Image 1 • Two red-emitting fluorescent probes SNARF-SSPy and SNARF-SeSPy have been designed for efficient detection of H 2 S. • By comparing the two probes, only SNARF-SeSPy exhibited excellent anti-interference even in the presence of high concentration of thiols. • Results of imaging H 2 S in living cells and zebrafish demonstrated that SNARF-SeSPy could be employed to track exogenous and endogenous H 2 S in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Abstract Recently, the fluorescence detection of H 2 S in biological systems has attracted the attention of many analytical chemists. However, most of H 2 S probes showed shorter fluorescence emission (<600 nm) with fluorescence intensity change induced by H 2 S, which has some disadvantages of shallower tissue penetration and bigger autofluorescence interference. Herein, we have rationally designed a near-infrared and ratiometric fluorescent probe (YC−1) for the detection of H 2 S based on isophorone. The detection process can be monitored by naked-eye. Addition of H 2 S, YC−1 showed that the emission ratios of fluorescence intensity at 540 and 660 nm (I540/I660) with an obvious enhancement from 0.05 to 13.3. Besides, the color of YC−1 changes from pink to yellow. As a probe for H 2 S, YC−1 exhibited better selectivity, better sensitivity and lower detection limits (0.17 μM). Moreover, YC−1 showed lower toxicity to HepG−2 cells and can be used for cell imaging. Graphical abstract Image 1 Highlights • 1. A novel ratiometric and near-infrared fluorescent probe for detecting H2S was developed. • 2. The probe showed higher selectivity and lower detection limit (0.17 μM) for H2S monitored by naked-eye. • 3. The probe can be used for monitoring exogenous and endogenous H2S in HepG-2 cells. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) is widely considered to be an endogenous signaling molecule that plays a crucial role in metabolic processes. Effective chemical tools that can modulate H 2 S levels in vivo contribute to understanding of H 2 S related biology as well as its potential therapeutic effects. As a consequence, we designed and synthesized a series of scavengers based on the 7-nitro-1,2,3-benzoxadiazole-piperazine conjugates from NBD-P1 to NBD-P5 were investigated to determine the down regulation of H 2 S levels. Among them, scavenger NBD-P5 permits a superior kinetic reaction ratio (55.43 M−1s−1), rapid response time (3 min), and a broad linear concentration range of H 2 S (200−600 μM). Notably, NBD-P5 displayed excellent selectivity of H 2 S and avoided interference from other competing physiological nucleophiles (Cys, GSH, and Hcy), reactive oxygen species (SO 3 2-, ·OH, and ClO-), and biologically related ions (NO3-, NO2-, and PO 4 3-). Furthermore, it is able to efficiently scavenge exogenous and endogenous H 2 S in living cells and zebrafish, which will provide the necessary improvements for design of diverse specific scavengers in complex biological systems. [Display omitted] • NBD derivatives show efficient H 2 S scavenging in living cells and zebrafish. • NBD derivatives exhibit high selectivity and rapid responsiveness. • A general platform provides some reference to regulate H 2 S levels in vivo. [ABSTRACT FROM AUTHOR]

We designed and synthesized a novel BODIPY-based fluorescent probe for sequential detection of Cu2+ and H 2 S based on displacement approach. Furthermore, the probe BC-DPA was successfully applied to detect Cu2+ in living cells on the basis of its noticeable permeability and low cytotoxicity. • A novel Cu2+ fluorescent probe employing BODIPY as fluorophore and DPA as Cu2+ chelator, named BC-DPA , was synthesized. • BC-DPA-Cu2+ can be used to detect H 2 S based on the Cu2+ displacement approach. • BC-DPA successfully detected the fluctuating concentration of Cu2+ in living cells. A new BODIPY-based fluorescent probe (BC-DPA) was prepared by a simple method for Cu2+ detection in aqueous media and living cells. BC-DPA displayed excellent selectivity toward Cu2+ via fluorescence "turn-off" mode when a mononuclear Cu(Ⅱ) complex is formed. The corresponding BC-DPA-Cu(Ⅱ) complex, whose structure was characterized by X-ray crystallography, has Cu(Ⅱ) in a distorted octahedral geometry. On the basis of the displacement approach, the fluorescence of BC-DPA-Cu2+ was recovered in the presence of S2-, which allowed the system to act as a sensitive "turn-on" sensor for hydrogen sulfide. Furthermore, BC-DPA exhibited noticeable permeability and low cytotoxicity, making it a useful tool to detect Cu2+ in biosystems. [ABSTRACT FROM AUTHOR]

• Naphthalimide-based a lysosome-targeting fluorescent probe LyNP-H 2 S for H 2 S sensing. • LyNP-H 2 S displays a significant 262-fold fluorescence intensity enhancement in the presence of H 2 S at 540 nm. • Moreover, LyNP-H 2 S can rapid image H 2 S in lysosome and inflamed tissues. Since the fluctuation of cellular hydrogen sulfide (H 2 S) is a very important third endogenously generated gaseous signaling molecule and plays a key role in the development of numerous human disorders, the real-time fluorescence detection of H 2 S in living systems has attracted plenty of interest during past decade. Although a lot of H 2 S fluorescent probes have been reported, the relationship between the physiology and pathology of H 2 S in organelles remains unclear, especially for inflammatory tissue. In this work, by adopting a weakly basic morpholine group as the lysosome-targeting site, a naphthalimide derivative as the signal reporter group and a 4-dinitrobenzene-ether (DNB) as fluorescence signal quencher and H 2 S-selective recognition moiety, we reported a new lysosome-targeting TP fluorescent probe LyNP-H 2 S for H 2 S detection and imaging in living cells and inflamed tissues. The probe LyNP-H 2 S exhibits very low fluorescence signal in the absence of H 2 S, and displays a significant 262-fold fluorescence intensity enhancement in the presence of H 2 S at 540 nm. Moreover, LyNP-H 2 S has the capability of quantitative detection of H 2 S at concentrations ranging from 0 to 12.0 μM (limit of detection = 9.8 nM), rapid response, as well as high sensitivity and selectivity toward H 2 S. Impressively, the results of living cell and inflamed tissues imaging test demonstrate that LyNP-H 2 S has the potentiality of being an ideal probe for real-time H 2 S detection in biosystems. [ABSTRACT FROM AUTHOR]

The active sulfur small molecules such as biothiols, hydrogen sulfide, hydrogen polysulfides and sulfur dioxide are closely related to various diseases in the biological system and have important physiological and pathological functions. Small-molecule fluorescent probes enable to detect and image active sulfur small molecules by virtue of their non-invasiveness, fast response times, and real-time in situ detection capability. Based on the inherent characteristics of active sulfur small molecules, many fluorescent probes have been reported to detect and image them. In this review, we classify the fluorescent probes according to the different type reaction of each small molecule, and summarize the reaction mechanism in detail. Moreover, we also emphasize the challenges of active sulfur small molecules-responsive fluorescent probes, hoping to provide a general implication for future research. • Summarised the latest developments in fluorescent probes for detecting small active sulfur molecules. • Classification was based on different reaction mechanism, and discussed the sensing mechanism of probes in detail. • Summarised a list of the involved probes, and compared the related sensing performance of the reported probes. • 147 references were contained and 104 probes were discussed. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H 2 S) plays a vital role in biological systems, so it is important to develop new methods for monitoring H 2 S with high selectively and sensitivity. In this study, we report the efficient solid phase synthesis of a new peptide-based bioprobe L that mimics the Cu(II) binding sites of ceruloplasmin. L exhibits highly sensitive colorimetric and fluorescent "turn off" responses to Cu2+ with high selectively among various metal ions over a broad pH range in 100% aqueous solutions. Interestingly, as a new promising analytical bioprobe, the L -Cu ensemble can monitor H 2 S by both colorimetric and fluorescent changes, and the limit of detection (LOD) is found to be as low as 14.7 nM. The reversibility experiment indicated that L could be recycled many times as reversible bioprobe. It is worth noting that L could be used to detect Cu2+ and H 2 S specifically in two real samples. Moreover, L exhibited excellent water-solubility and low biotoxicity even at high concentrations based on MTT study, and cell imaging results indicated that it can be applied to detecting Cu(II) and H 2 S in living RKO cells monitored by confocal fluorescence microscopy imaging. • A novel fluorescent bioprobe L was synthesized by mimic the binding sites of the ceruloplasmin for Cu(II) ions. • The L -Cu ensemble for highly selective and sensitive detection of H 2 S and detection limits of 14.7 nM. • The reversibility and cyclicity being imparted to the L during the detection of Cu2+ and H 2 S. • L exhibited low biotoxicity, and showed its potential application for detection of Cu(II) and H 2 S in living cells. [ABSTRACT FROM AUTHOR]

In this article, a novel fluorescent probe (NRBE) for detecting H 2 O 2 was developed using benzyl boronic ester as the H 2 O 2 -recognized group and Nile red as the matrix. The probe has several advantages, such as good selectivity, high sensitivity (LOD = 75 nM), good water solubility and emission in the near-infrared region (ex/em:585/670 nm). With the NRBE probe, the endogenous H 2 O 2 in human hepatocellular carcinoma cells BEL-7402, was detected, and the H 2 O 2 generated during the ischemia-reperfusion of the cells was imaged. These results show that NRBE can be applied for real-time detection of H 2 O 2 in biological systems. Unlabelled Image • A novel Nile red-based fluorescent probe NRBE was designed and synthesized for H 2 O 2 detection. • The probe has good selectivity, high sensitivity, good water solubility and emission in the near-infrared region. • The probe can be applied for real-time detection of H 2 O 2 in biological systems. [ABSTRACT FROM AUTHOR]