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The selective detection of hydrogen sulfide in physiological and pathological processes has gained substantial attention in recent years. However, the real-time detection of hydrogen sulfide remains an elusive goal. In this work, a new type of hemicyanidin-based fluorescent "turn-on" probe NTR-HS (Ex = 680 nm, Em = 760 nm) was developed to detected H2S in a very short time (3 min). The fluorescence quantum yield is 0.15 and accompanied with a noticeable color change from violet to blue that can be used to detect H2S in the range 1.04 × 10−7–4 × 10−5 M with a limit of detection of 1.04 x 10-7 M. The NTR-HS probe was also used for imaging of endogenous hydrogen sulfide and mitochondrial localization in HCT116 and HeLa cells. The detection mechanism was studied through fluorescence, UV–Vis, NMR, and mass analysis. Notably, the probe was successfully used to imaging H2S in mice and locating hydrogen sulfide in the large intestine of mice. [ABSTRACT FROM AUTHOR]

Some biological small molecules such as hydrogen sulfide (H 2 S) and hypochlorous acid (HClO), play pivotal roles in numerous biological and pathological processes and are associated with various diseases. The detection and monitoring them is of continued research interest. Here we report a sequential detection mode fluorescence probes that allow for the sensing of HS– and ClO–. The mixture of P and HS– constructs a specific sensing system S for ClO–. The substitution product S is stable in air, which also could be used independently. Mechanism studies demonstrate that HS– substitutes the Cl atom in P. Furthermore, the addition of ClO– facilitates a ring-forming reaction, resulting in the formation of a thiofuran ring within the product (T). Interestingly, P has a highly ordered steric packing and could self-assemble into a rice-spike-like structure. Upon the addition of HS–, the assemblies decompose into free molecules. After interaction with ClO–, these molecules further transform to T with strong assembled capacity, featuring a larger number of nanosheets. This study provides a novel mechanism for sensing HS– and ClO–, cell and living animal imaging further indicating the good application prospects of these probes in biosensing and bioimaging. [Display omitted] • Three fluorescent probes for detection HS– and ClO– in sequence were developed. • The responsiveness to ClO– is based on the thiofuran ring-forming reaction. • The self-assembly may play positive roles in the detection of HS– and ClO–. • These probes were applied as HS− and ClO− imaging in living cells and mice. [ABSTRACT FROM AUTHOR]

We reported a novel near-infrared emitting fluorescent probe WFP-PC, which contained a positive charged hemicyanine-based WFP-OH as fluorophore and thiobenzoate unit as a specific reaction site. The probe exhibited excellent H 2 S sensing performance with significant fluorescence enhancement and response time within 4 min and detection limit as low as 0.47 μM. The probe was successfully applied to imaging H 2 S in cells, suggesting it could be a promising molecular tool for H 2 S detection in real samples. [Display omitted] • The novel hemicyanine-based NIR probe was developed. • The probe showed high selectivity and sensitivity for H 2 S detection, accompanying color changes from purple to blue. • The probe was successfully used as monitoring the variation of both exogenous and endogenous H 2 S in living cells and mice. Hydrogen sulfide (H 2 S) plays an important role in regulating varieties of important physiological and pathological processes. Thus the development of fluorescent probe for the detection of H 2 S is of great significance and has attracted much attention recently. Herein, we reported a novel near-infrared (NIR) emitting fluorescent probe WFP-PC, which contained a positive charged hemicyanine-based WFP-OH as fluorophore and thiobenzoate unit as a specific reaction site. After treated with H 2 S, the probe exhibited significant fluorescence enhancement and response time within 4 min and detection limit as low as 0.47 μM, accompanied by color changes from purple to blue. The probe was successfully applied to imaging the exogenous/endogenous H 2 S in cells and mice, suggesting it could be a promising molecular tool for H 2 S detection in living systems. [ABSTRACT FROM AUTHOR]

Herein, we reported a novel probe with near-infrared fluorescent emission (750 nm) and a large Stokes shift (118 nm) for the detection of H 2 S. The probe can specific and sensitive detection (LOD as low as 4.5×10–8 M) of H 2 S, accompanying an ideal color changes from purple to green natural light, which could rapid detect HS– over other analytes through the "naked eye". The probe was successfully be utility for H 2 S image in cells and mice. [Display omitted] • The novel NIR probe was developed based on the nucleophilic substitution mechanism. • The probe can specific and sensitive detection of H 2 S, accompanying color changes from purple to green. • The probe can be used as a useful tool for studying the physiological and pathological phenomena related to hydrogen sulfide. As a kind of gas signal molecules, H 2 S is related to in human health and disease. Herein, we developed a novel probe with near-infrared fluorescent emission (750 nm) and a large Stokes shift (118 nm) for the detection of H 2 S. The probe can specific and sensitive detection (LOD as low as 4.5 × 10–8 M) of H 2 S, accompanying an ideal color changes from purple to green natural light. Based on the advantages of excellent cell permeability and cytotoxicity data, the probe was be utility for H 2 S image in cells and mice. [ABSTRACT FROM AUTHOR]

Intracellular pH has been associated with multiple biological processes. However, fluorescent probes for pH are limited. Herein, a new pH fluorescent probe was developed based on reversible structural changes. This probe provided three reversible pH response modes within 2.00–12.00. Under the acidic conditions, there is no-fluorescence, under the neutral conditions, the emission is at 650 nm, under the alkaline conditions, the emissions at 650 nm decreases and at 460 nm appears and increases simultaneously. The probe solution presented distinct colors response to the pH values from 2.00 to 12.00. The fluorescent response from pH 2.00–12.00 makes the probe suitable for the monitoring pH in living cells. Moreover, the imaging results confirm that probe S can be applied in fluorescence imaging in living cells. • A new pH fluorescent probe was developed based on reversible structural changes. • The probe provided three reversible pH response modes accompanied by different color changes. • The probe can be applied to live cell pH monitoring and lysosome imaging. [ABSTRACT FROM AUTHOR]

We have successfully developed a bis-schiff base fluorescent probe L, linking hemicyanine aldehyde and salicylaldehyde through hydrazine hydrate, which continuously identify Fe3+ and F− in MeCN-Tris (v/v, 2:1, 10 mM, pH 7.3) solution. The probe L showed a highly selective and sensitive fluorescence "turn-on" for Fe3+ over other metal ions accompanying with the solution color change from yellow to red. Furthermore, the resulting L-Fe3+ complex detect only F− among the common various anions. The bonding mechanisms were detected by fluorescence and absorption titrations, 1H NMR titrations, HRMS and theoretical calculations. In addition, the probe has been used for liquid colorimetry and test paper colorimetric identification of Fe3+. Moreover, the probe L was used for sequentially off-on-off fluorescence imaging of Fe3+ and F− in HeLa cells. In this study, we have successfully developed a bis-schiff base fluorescent probe L, linking hemicyanine aldehyde and salicylaldehyde through hydrazine hydrate, which continuously identify Fe3+ and F− in MeCN-Tris (v/v, 2:1, 10 mM, pH 7.3) solution. The probe L showed a highly selective and sensitive fluorescence "turn-on" for Fe3+ over other metal ions accompanying with the solution color change from yellow to red. Furthermore, the resulting L-Fe3+ complex detect only F− among the common various anions. The bonding mechanisms were detected by fluorescence and absorption titrations, 1H NMR titrations, HRMS and theoretical calculations. In addition, the probe has been used for liquid colorimetry and test paper colorimetric identification of Fe3+. Moreover, the probe L was used for sequentially off-on-off fluorescence imaging of Fe3+ and F− in HeLa cells. [Display omitted] • A new hemicyanidine-based colorimetric-fluorescent probe L was synthesized. • The probe L can detect Fe3+ and F− ions in aqueous solutions. • The binding modes of probe L with Fe3+ have been well demonstrated by MS, 1H NMR and DFT calculation. • The probe L had the potential application value for monitoring Fe3+ and F− ions in environment and vivo. [ABSTRACT FROM AUTHOR]

In this study, a novel fluorescent probe, Doc-Ac, was prepared and displayed highly selectivity to Cys with a relatively large Stokes shift (165 nm) and fast fluorescence response (within 7 min.) in almost 100 % aqueous solution at a physiological pH. In addition, the probe displayed low toxicity and had been successfully used in fluorescence imaging of endogenous Cys and selectively discriminate the intracellular Cys from GSH and Hcy in living cells and mice. To the best of our knowledge, this is the first report on the real-time visualization and fast response of Cys in a living animal in almost 100 % aqueous solution. [Display omitted] • The probe is easy to be prepared. • The probe can rapidly, high sensitivity and selectivity detect Cys with a large Stokes shift in aqueous solution. • The probe successfully applied to detect endogenous Cys in living cells and mice. A novel fluorescent probe based on hydroxyquinoline conjugated with benzothiazolyl unit dye Doc-Ac was prepared. The results of fluorescent and absorption spectroscopic responses towards amino acids showed that the probe had a capability of rapidly and selectively detecting cysteine over other amino acids with a large stokes shift in aqueous solution. The sensing mechanism was proved by the proton NMR and high resolution mass spectrometry analysis. The fluorescence images indicated that this probe could discriminate the exogenous/endogenous cysteine in living cells and mice. [ABSTRACT FROM AUTHOR]