H2S In Aqueous Solutions Research Articles

Improving contaminant removal and inhibiting CH4 and H2S emissions from septic tanks: Nitrified human urine as a source of electron acceptor

Septic tanks are widely adopted in decentralized household wastewater treatment systems serving billions of people globally. Due to the lack of effective electron acceptors, insufficient nutrient removal and the emission of harmful gases, e. g. H2S, CH4, etc., are the common drawbacks. In the present work, we attempted to supplement nitrite into septic tanks as an electron acceptor, via nitrifying human urine source-separated from blackwater, to overcome these drawbacks. Partial or complete nitritation of source-separated urine was achieved in a sequencing batch reactor. The addition of nitrified urine into septic tanks improved organic and nitrogen removals in blackwater up to 90 % and 70 %, respectively. The emission of harmful gases from the septic tanks was stably diminished, with more than 75 % of CH4, CO2 and H2S reductions. Nitrite addition significantly reduced the abundance of hydrogenotrophic methanogens in septic tanks. Though the activity of sulfate-reducing bacteria recovered after the initial inhibition upon nitrite addition, the bio-generated H2S was retained in water since the increased wastewater pH after nitrite addition promoted the disassociation of H2S in aqueous solution.

Upconversion-based chiral nanoprobe for highly selective dual-mode sensing and bioimaging of hydrogen sulfide in vitro and in vivo

Chiral assemblies have become one of the most active research areas due to their versatility, playing an increasingly important role in bio-detection, imaging and therapy. In this work, chiral UCNPs/CuxOS@ZIF nanoprobes are prepared by encapsulating upconversion nanoparticles (UCNPs) and CuxOS nanoparticles (NPs) into zeolitic imidazolate framework-8 (ZIF-8). The novel excited-state energy distribution-modulated upconversion nanostructure (NaYbF4@NaYF4: Yb, Er) is selected as the fluorescence source and energy donor for highly efficient fluorescence resonance energy transfer (FRET). CuxOS NP is employed as chiral source and energy acceptor to quench upconversion luminescence (UCL) and provide circular dichroism (CD) signal. Utilizing the natural adsorption and sorting advantages of ZIF-8, the designed nanoprobe can isolate the influence of other common disruptors, thus achieve ultra-sensitive and highly selective UCL/CD dual-mode quantification of H2S in aqueous solution and in living cells. Notably, the nanoprobe is also capable of in vivo intra-tumoral H2S tracking. Our work highlights the multifunctional properties of chiral nanocomposites in sensing and opens a new vision and idea for the preparation and application of chiral nanomaterials in biomedical and biological analysis.

Development of a fluorescent sensor for dual visual detection of Cr3+ and H2S using a fluorescein framework and bio-imaging applications

A novel responsive fluorescent sensor derived from a fluorescein framework has been successfully fabricated for highly selective dual recognition of Cr3+ and H2S in aqueous solution. Bisanthraflu demonstrated excellent selectivity and great sensitivity towards Cr3+ with a non-fluorescent complex of bisanthraflu-Cr3+ formation via a 2:1 binding mode with minimum detectable amount of 1.7 μM. The fluorescent intensity of the bisanthraflu-Cr3+ complex was markedly restored in the presence of H2S via the displacement approach, potentially applicable as a highly responsive probe for H2S detection with a low detectable concentration of 1.95 μM. This dual functional fluorescent sensor with an On-Off-On approach demonstrated potential for detecting H2S in live HeLa cells with not significant cytotoxicity.

Construction of a mitochondria-targeted near-infrared fluorescence turn-on fluorescent probe for H2S detection and imaging in living cells and drug-induced mice inflammatory models

The mechanism of the interaction between the signaling molecule hydrogen sulfide (H2S) and mitochondria and its related diseases is difficult to elusive. Thus it is urgent to develop effective methods and tools to visualize H2S in mitochondria and in vivo. In this work, a robust mitochondrial-targeting NIR fluorescence “turn-on” fluorescent probe, NIR1, was reported, by adopting a Changsha-OH near-infrared (NIR) dye as the NIR fluorophore, a 2,4-dinitrophenyl (DNB) moiety as both the responsive site of the H2S and the fluorescence quenching group of the NIR fluorophore, and an oxygen onium ion site as the mitochondria-targeting group, for the detection and analysis of H2S in living Raw 264.7 cells and drug-induced inflammatory mice models. NIR1 exhibited a much smaller background fluorescence signal in lack of H2S, whereas strong enhanced NIR fluorescence “turn-on” was detected in the presence of H2S, these results showed a low detection limit (30.2 nM) for quantitative detection of H2S in aqueous solutions with concentrations ranging from 0 to 1 μM H2S. These characteristics were beneficial to direct detection and imaging analysis of H2S in complicated biosystems. Therefore, first, NIR1 was applied for the NIR detection of mitochondrial H2S in living inflammatory cells with satisfactory results. Finally, NIR1 was applied to detect H2S in drug-induced inflammatory mice models with agreeable results, demonstrating that NIR1 as a molecular tool has an excellent practical application in the study of the interaction between inflammatory and H2S.

A turn-on fluorescent nanosensor for H2S detection and imaging in inflammatory cells and mice

Hydrogen sulfide (H2S) is an endogenously generated gaseous signaling molecule and is known to be involved in the occurrence and development of inflammation. To better understand its physiological and pathological process of inflammation, reliable tools for H2S detection in living inflammatory models are desired. Although a number of fluorescent sensors have been reported for H2S detection and imaging, water-soluble and biocompatibility nanosensors are more useful for imaging in vivo. Herein, we developed a novel biological imaging nanosensor, XNP1, for inflammation-targeted imaging of H2S. XNP1 was obtained by self-assembly of amphiphilic XNP1, which was constructed by the condensation reaction of the hydrophobic, H2S response and deep red-emitting fluorophore with hydrophilic biopolymer glycol chitosan (GC). Without H2S, XNP1 showed very low background fluorescence, while a significant enhancement in the fluorescence intensity of XNP1 was observed in the presence of H2S, resulting in a high sensitivity toward H2S in aqueous solution with a practical detection limit as low as 32.3 nM, which could be meet the detection of H2S in vivo. XNP1 also has a good linear response concentration range (0–1 μM) toward H2S with high selectivity over other competing species. These characteristics facilitate direct H2S detection of the complex living inflammatory cells and drug-induced inflammatory mice, demonstrating its practical application in biosystems.

Growth of AgI semiconductors on tailored 3D porous Ti3C2 MXene/graphene oxide aerogel to develop sensitive and selective “signal-on” photoelectrochemical sensor for H2S determination

Long term exposure to hydrogen sulfide (H2S) even in low concentration poses a serious threat to human health and the ecosystem, pointing to the significance for its effective supervision. In this study, we report a sensitive and selective “signal-on” photoelectrochemical (PEC) sensor for the determination of toxic H2S in aqueous solution by in situ growth of AgI semiconductors on tailored three-dimensional (3D) porous Ti3C2 MXene/graphene oxide aerogel (MGA). Our research demonstrated that the resultant MGA with the starting feeding mass ratio of MXene and graphene oxide (GO) of 1:8 (MGA1:8) possessed the most excellent PEC performance after the growth of AgI semiconductors than their monomers (Ti3C2 MXene and GO) and the MGAs with other starting feeding mass ratio. Such designed PEC sensor based on MGA1:8/AgI heterojunction showed dramatically strengthened PEC responses with increasing concentrations of S2−. Correspondingly, a wide linear range of 5 nM–200 μM, a low limit of detection of 1.54 nM (S/N = 3), and exclusively unique selectivity have been achieved. Our research illustrates that the PEC sensor designed with tailored MGA constitutes is an effective pathway to enhance the overall sensing performance, which will envision to boost more efforts for advanced 3D porous aerogel using in PEC sensors.

A Golgi Apparatus‐Targetable Probe Based on Lanthanide Complexes for Ratiometric Time‐Gated Luminescence Detection of Hydrogen Sulfide

AbstractDevelopment of bioanalytical methods for selective and accurate detection of H2S in living samples is essential for understanding the pathological and physiological functions of this gasotransmitter in biological systems. Here we report a Golgi apparatus‐targetable lanthanide complex‐based luminescent probe, Golgi‐ABTTA‐Eu3+/Tb3+, that can be used for accurately determining H2S in aqueous solution and living cells via the ratiometric time‐gated luminescence (RM‐TGL) technique. This probe is composed of 2,2′:6′,2′′‐terpyridine‐Eu3+/Tb3+ mixed complexes as the luminophore, 4‐azidobenzyl‐ether as the responsive moiety, and sulfanilamide as the Golgi apparatus‐targeting moiety. Upon reaction with H2S, accompanied by the cleavage of 4‐azidobenzyl group from the probe molecule, the long‐lived emission of Tb3+ complex at 540 nm is significantly enhanced, while that of Eu3+ complex at 610 nm is obviously reduced. It was noted that the I540/I610 ratio increased by 8.8 times after the probe was exposed to H2S, which enabled H2S to be detected with RM‐TGL method. After being incubated with living cells, the probe molecules were selectively accumulated in the Golgi apparatus, which allowed H2S in the Golgi apparatus to be successfully imaged in RM‐TGL mode.

A highly sensitive and selective fluorescence turn-on probe for the sensing of H2S in vitro and in vivo

A fluorescence turn-on probe, 2-butyl-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-6-yl 2,4-dinitrobenzenesulfonate (NT-SH), has been constructed for sensing of hydrogen sulfide (H2S). NT-SH exhibited excellent detection performance including favorable water solubility, low fluorescence background, high enhancement (45-fold), large linear response range (0–50 μM) and low detection limit (80.01 nM) for H2S in aqueous. In addition, the response mechanism of NT-SH for H2S was confirmed by the theoretical calculation and mass spectral analysis. More importantly, the imaging experiments of H2S in vitro and in vivo confirmed that NT-SH had low cytotoxicity, and favorable biocompatibility. In addition, it illustrated that NT-SH was able to detected exogenous H2S in living cells and zebrafish. These results suggested that NT-SH can be act as a potential molecular tool for detecting of H2S in aqueous solution, in vitro and in vivo.

A minimalist ratiometric fluorescent sensor based on non-covalent ternary platform for sensing H2S in aqueous solution and serum

Great efforts have been made to detect hydrogen sulfide (H2S) due to its involvements in various physiological processes and disease diagnosis. In the present work, a novel dansyl-based derivative (DBr) was synthesized and used as a FRET donor, and pyronine Y (PyY) was used as a FRET acceptor for constructing a ratiometric fluorescent sensor with assisstance of surfactant. The non-covalent ternary sensor platform could interact with H2S, causing an orange to blue-green fluorescence change as the acceptor emission decreased and the donor emission increased. The remarkable ratiometric response empowers the present system a high sensitivity to H2S with a detection limit of 110 nM. Moreover, the detection of H2S in serum could also be realized, providing the possibility for practical applications.

Naphthalimide-based a highly selective two-photon fluorescent probe for imaging of hydrogen sulfide in living cells and inflamed tissue of mouse model.

Hydrogen sulfide (H2S) is a very important third endogenously generated gaseous signaling molecule and plays a key role in physiological and pathological regulation processes of living biosystems. Although a lot of H2S fluorescent probes have been reported, the relationship between the physiology and pathology of H2S in inflamed tissues remains unclear. Herein, by adopting a donor-π-acceptor (D-π-A)-structured naphthalimide derivative as the two-photon (TP) fluorophore and a 4-dinitrobenzene-ether (DNB) with a strong intramolecular charge transfer (ICT) effect as the recognition moiety, we reported a novel TP bioimaging probe NP-H2S for H2S with improved sensitivity. The NP-H2S exhibits very low background fluorescence in the absence of H2S, and a significant 258-fold fluorescence intensity enhancement was observed in the presence of H2S, resulting in a high sensitivity and selectivity to H2S in aqueous solutions with a detection limit of 18.8nM observed. The probe also shows a wide linear response concentration range (0-10.0μM) to H2S with high selectivity. All these features are favorable for direct monitoring of H2S in complex biological samples. It was then applied for direct TP imaging of H2S in tissues of inflammation model with satisfactory sensitivity, indicating it has the latent capability in further biological applications for investigation of the interaction H2S with inflammation.

Unveiling the role of bisulfide in the photocatalytic splitting of H2S in aqueous solutions

Anaerobic photocatalytic conversion of aqueous H2S to H2 was tested on Pt-decorated N-doped TiO2 grown on graphene. The hydrogen production increased linearly (rate: 32.3 μmol/h/g, quantum yield: 1.4 × 10–4) with HS− concentration, until the critical value of 0.029 mol/dm3, after which it declined to negligible values. The latter was attributed to photon-blockage caused by sulfur-containing species formed on catalyst surface, which could be removed by simple washing of the catalyst leading to its regeneration, as highlighted by the characterization of fresh and used catalyst. Similar tests performed at constant HS− concentration and variable pH did not yield a correlation, thus suggesting HS− as the major source of H2, and not H+. A new kinetic model assessing the competitive adsorption mechanism reiterated the important role of sulfide ionic species in hydrogen production. A strong correlation between the latter and HS− concentration was established based on the reactivity results and proposed mechanism.

Responsive nanosensor for ratiometric luminescence detection of hydrogen sulfide in inflammatory cancer cells

Gasotransmitter hydrogen sulfide (H2S), produced enzymatically in body, has important functions in biological signaling and metabolic processes. An abnormal level of H2S expression is associated with different diseases, therefore, development of novel bioanalytical methods for rapid and effective detection of H2S in biological conditions is of great importance. In this work, we report the development of a new responsive nanosensor for ratiometric luminescence detection of H2S in aqueous solution and live cells. The nanosensor (Ru@FITC-MSN) was prepared by immobilizing a luminescent ruthenium(II) (Ru(II)) complex into a fluorescein isothiocyanate (FITC) conjugated water-dispersible mesoporous silica nanoparticle (MSN), showing dual emission bands at 520 nm (FITC) and 600 nm (Ru complex). The red luminescence of the formed Ru@FITC-MSN was quenched in the presence of Cu2+. The in-situ generated Ru–Cu@FITC-MSN responded to H2S rapidly and selectively, showing a linear ratiometric luminescence change in FITC and Ru(II) channels with the H2S concentration (0.5–4 μM). Limit of detection (LoD) and limit of quantification (LoQ) were determined to be 0.36 and 1.21 μM. Followed by investigation of cellular uptake processes, the utility of the nanosensor for ratiometric imaging of H2S in live cells and its capability to monitor H2S levels in inflammatory breast cancer cells were then demonstrated. This study provides a powerful approach for detection of highly reactive and unstable H2S biomolecules in live systems.

Surface functionalization of mesoporous silica nanoparticles with pyronine derivative for selective detection of hydrogen sulfide in aqueous solution

The selective detection of hydrogen sulfide (H2S) in aqueous solution has drawn increasing attention over the past decade. Although many fluorescent chemosensors in homogeneous solutions have been developed, the creation of rapid, highly sensitive and selective fluorescent nanoparticle sensors for detection of H2S are still less reported. In the present work, a novel organic-inorganic composite fluorescent sensor, M-SiO2@PYR, was synthesized by covalent coupling pyronine (PYR) on the solid surface of mesoporous silica nanoparticles. The obtained mesoporous nanoparticles were characterized by TEM and BET measurements. The chemical immobilization of organic fluorophores on the silica nanoparticles were analyzed by FT-IR, XPS, TGA, and solid state NMR methods. The fluorescent mesoporous nanoparticle sensor, M-SiO2@PYR, was found to show sensitive and selective quenching responses toward H2S in aqueous solution compared to a series of competitive analytes. The nanoparticle sensor also displayed a low detection limit of 103.6 nM to H2S, illustrating a high sensitivity. Moreover, the detection of H2S could be also realized in biological fluids like serum or urine. The present work provides a novel way to prepare fluorescent sensor for detecting biothiols in aqueous solution, which may be further used to develop discriminative sensor for multiple biothiols by modulating surface modification.

A new pyrene-based tert-butylnitroxide radical “off-on” fluorescent probe for H2S detection in living cells

A new pyrene-based tert-butylnitroxide radical 1-tert-butyl(pyrenyl)nitroxide (TBPNO) has been designed and synthesized with medium yield by two steps using 1-bromopyrene as the starting material, which has been fully characterized by the means of mass spectrum, single X-ray diffraction analysis, elemental analysis and electron spin resonance. In addition, the magnetic property of the title compound has been measured, which also confirms the single electron nature of radical. The photochemical properties of compound TBPNO have been investigated in detail under different pH environments and various biologically-related species. The results show that compound TBPNO displays excellent selectivity, sensitivity and quick response time for the detection of H2S in aqueous solution, as well as living cells by showing a significant ‘‘off–on’’ fluorescence change with the detection limit of 17.9 nM. The study on the recognition mechanism indicates that the detection of compound TBPNO for H2S can be attributed to the transformation of compound TBPNO to N-tert-butyl-1-pyrenylamine (Py-NH). This is the first H2S probe based on the nitroxide radical recognition site.

An optical H2S biosensor based on the chemoselective Hb-I protein tethered to a transparent, high surface area nanocolumnar electrode

Sensitive and selective detection of analytes in complex biological fluids can be an extremely challenging issue. The constructive association of biomolecules and transparent mesoporous electrodes is of interest in this area, as it can lead to innovative biosensors combining optical and electrochemical detection modes. This concept, however, requires the development of appropriate surface functionalization methodologies that are robust enough for long-term operation in physiological environments. In the present work, the high-surface area of 3D transparent mesoporous indium-tin oxide (ITO) electrodes (prepared by glancing angle deposition or GLAD) has been chemically functionalized with recombinant hemoglobin I from Lucina pectinata according to a versatile 2-step process. First, 4-diazoniumbenzoic acid salt is covalently electrografted onto the ITO surface, followed by amide coupling of the protein. The resulting electrodes were quantitatively characterized by cyclic voltammetry and UV–vis absorption spectroscopy, demonstrating high surface coverages (up to 45% of a closed-packed monolayer for Hemoglobin-I) and homogeneous distribution across the entire thickness of the GLAD mesoporous structure. Good stability is also observed when the modified electrodes are immersed for prolonged times in a high ionic strength saline buffer. We also show that the hemoglobin I-modified electrode can be used as an optical biosensor for the selective, reversible, and fast detection of H2S in aqueous solutions over a ∼two-decade concentration range (i.e. up to 10 μM) and with a limit of detection of 0.35 μM. Good analytical performance was also achieved in human plasma without significant interference from the biological matrix.

Use of natural Stipa tenacissima fibers for the removal of H2S in an alkaline aqueous medium

The current research aims to use plants as substituent of chemical additives in the elimination of pollutants, therefore making polluting industries environmentally friendly. In the present work, the potential use of Stipa tenacissima (cultivated in the dry region of North Africa) in the removal of H2S in aqueous solution was investigated. The obtained experimental results showed successful elimination of H2S through reaction with Stipa tenacissima fibers in an alkaline aqueous medium. The effect of Stipa tenacissima’s mass, temperature ranging 20–60 °C, and aeration on sulfide removal efficiency was examined. The study clearly revealed that the aeration processes enhanced the removal reaction, and the increase in temperature gave a better removal rate with an optimal mass ratio of Stipa tenacissima of 0.1 g to eliminate 0.2 mg H2S.

Measuring and correlating solubility of hydrogen sulfide in aqueous solution of 2-((2 aminoethyl)amino)ethanol

The solubility of hydrogen sulfide (H2S) in aqueous solution of 2-((2-aminoethyl)amino)ethanol (AEEA) at low and medium pressures was determined for two different concentrations (i.e. 10 and 30 wt%). The experimental total pressure varied from (9.5 to 1594) kPa and the experimental temperature was set to (313.2, 328.2, 343.2 and 358.2) K. The experimental data are presented as the total pressure against acid gas loading (mole H2S per mole of AEEA). The Deshmukh-Mather model and Peng-Robinson equation of state were used for the liquid and vapour phase, respectively, to correlate the solubility of H2S in aqueous solutions of AEEA. The average absolute deviation percent (AAD%) in calculating the total pressure as a function of H2S loading obtained 5.0% for (AEEA– H2O–H2S) ternary system at the four values of temperature. The enthalpy change of the absorption of H2S in the 10 and 30 wt% aqueous solution of AEEA was also estimated with the tuned model.

PH-Controlled Hydrogen Sulfide Release for Myocardial Ischemia-Reperfusion Injury.

Hydrogen sulfide (H2S) is a critical signaling molecule that regulates many physiological and/or pathological processes. Modulation of H2S levels could have potential therapeutic value. In this work, we report the rational design, synthesis, and biological evaluation of a class of phosphonamidothioate-based H2S-releasing agents (i.e., H2S donors). A novel pH-dependent intramolecular cyclization was employed to promote H2S release from the donors. These water-soluble compounds showed slow, controllable, and pH-sensitive production of H2S in aqueous solutions. The donors also showed significant cytoprotective effects in cellular models of oxidative damage. Most importantly, the donors were found to exhibit potent cardioprotective effects in an in vivo murine model of myocardial ischemia-reperfusion (MI/R) injury through a H2S-related mechanism.

Delayed Treatment with Sodium Hydrosulfide Improves Regional Blood Flow and Alleviates Cecal Ligation and Puncture (CLP)-Induced Septic Shock.

Cecal ligation and puncture (CLP)-induced sepsis is a serious medical condition, caused by a severe systemic infection resulting in a systemic inflammatory response. Recent studies have suggested the therapeutic potential of donors of hydrogen sulfide (H2S), a novel endogenous gasotransmitter and biological mediator in various diseases. The aim of the present study was to assess the effect of H2S supplementation in sepsis, with special reference to its effect on the modulation of regional blood flow. We infused sodium hydrosulfide (NaHS), a compound that produces H2S in aqueous solution (1, 3, or 10 mg/kg/h, for 1 h at each dose level) in control rats or rats 24 h after CLP, and measured blood flow using fluorescent microspheres. In normal control animals, NaHS induced a characteristic redistribution of blood flow, and reduced cardiac, hepatic, and renal blood flow in a dose-dependent fashion. In contrast, in rats subjected to CLP, cardiac, hepatic, and renal blood flow was significantly reduced; infusion of NaHS (1 mg/kg/h and 3 mg/kg/h) significantly increased organ blood flow. In other words, the effect of H2S on regional blood flow is dependent on the status of the animals (i.e., a decrease in blood flow in normal controls, but an increase in blood flow in CLP). We have also evaluated the effect of delayed treatment with NaHS on organ dysfunction and the inflammatory response by treating the animals with NaHS (3 mg/kg) intraperitoneally (i.p.) at 24 h after the start of the CLP procedure; plasma levels of various cytokines and tissue indicators of inflammatory cell infiltration and oxidative stress were measured 6 h later. After 24 h of CLP, glomerular function was significantly impaired, as evidenced by markedly increased (over 4-fold over baseline) blood urea nitrogen and creatinine levels; this increase was also significantly reduced by treatment with NaHS. NaHS also attenuated the CLP-induced increases in malondialdehyde levels (an index of oxidative stress) in heart as well as in liver and myeloperoxidase levels (an index of neutrophil infiltration) in heart and lung. Plasma levels of IL-1β, IL-5, IL-6, TNF-α, and HMGB1 were attenuated by NaHS. Treatment of NaHS at 3 mg/kg i.p. (but not 1 mg/kg or 6 mg/kg), starting 24 h post-CLP, with dosing repeated every 6 h, improved the survival rate in CLP animals. In summary, treatment with 3 mg/kg H2S-when started in a delayed manner, when CLP-induced organ injury, inflammation and blood flow redistribution have already ensued-improves blood flow to several organs, protects against multiple organ failure, and reduces the plasma levels of multiple pro-inflammatory mediators. These findings support the view that H2S donation may have therapeutic potential in sepsis.

A water soluble and fast response fluorescent turn-on copper complex probe for H2S detection in zebra fish

According to the displacement method, herein we reported a water soluble copper complex [Cu(MaT-cyclen)2] as a fluorescent probe for the detection of H2S. For this, 1-((1-((10-methylanthracen-9-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-1,4,7,10-tetraazacyclododecane (MaT-cyclen) was synthesized first. To improve its solubility in aqueous media, sodium acetate group was introduced into 8-hydroxy-2-quinoline successfully. MaT-cyclen was chelated with Cu(II) to form [Cu(MaT-cyclen)2] complex, which displayed high sensitivity and selectivity for H2S over the other possible competitive substances on the basis of forming CuS. Meanwhile, [Cu(MaT-cyclen)2] displayed rapid response (<1min), well reversibility, lowest detection limit (205nM), and high sensitivity for recognizing H2S in aqueous solution. Furthermore, its potential utility for biological applications was confirmed by fluorescence imaging of H2S in live cells as well as in zebra fish.