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There is a potential synergistic effect between nonsteroidal anti-inflammatory drugs and hydrogen sulfide (H 2 S), but direct evidence for the study is lacking. With a single fluorescence detection method, it is difficult to accurately confirm the effectiveness of the synergistic effect. In this study, the fluorescent probe and the nonsteroidal anti-inflammatory drug naproxen were combined via different self-immolative spacer groups to obtain a diagnostic and therapeutic integrated fluorescent probe Nap-NP-NSB , which can release H 2 S. The quantitative release of H 2 S by Nap-NP-NSB was evaluated in vitro and in cells, and the synergistic effect of H 2 S and naproxen was confirmed by monitoring the treatment process of cellular inflammation and oxidative damage of gastric mucosa cells. Finally, in vivo fluorescence imaging and mass spectrometry imaging of the liver and stomach tissues and their sections were performed in the mouse model of acute hepatitis. The dual-modal detection method not only confirmed that Nap-NP-NSB had better anti-inflammatory activity and less gastric mucosal damage, but also enabled a more accurate visualization of the drug synergistic effect of naproxen and H 2 S. This work provides a dual visualization imaging method combining fluorescence and mass spectrometry imaging and develops a new idea for studying drug synergies based on self-immolative structures.

Hydrogen sulfide (H 2 S) is a key factor in various biological processes such as plant grow and its response to environmental stress. Here, we develop a novel near-infrared (NIR) fluorescent probe for detecting hydrogen sulfide based on the regulatory NIR dye pKa values. After triggering the H 2 S substitution response, probe A with introducing the cyano moiety not only exhibits a significant near-infrared emission (Emax: 724 nm) response in physiological environments, but also shows a fast response, high selectivity, and sensitivity (LOD as 0.52 µM). In addition, probe A with low biological cytotoxicity is successfully used for imaging detection of cellular exogenous and endogenous hydrogen sulfide. More importantly, in situ imaging of probe A tracks the H 2 S fluctuations in the rice root system and its response to environmental stress. Hence, this work offers a new NIR fluorescence imaging monitoring tool for hydrogen sulfide in biological systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

H 2 S plays a crucial role in numerous physiological and pathological processes. In this project, a new fluorescent probe, SG-H 2 S, for the detection of H 2 S, was developed by introducing the recognition group 2,4-dinitrophenyl ether. The combination of rhodamine derivatives can produce both colorimetric reactions and fluorescence reactions. Compared with the current H 2 S probes, the main advantages of SG-H 2 S are its wide pH range (5-9), fast response (30 min), and high selectivity in competitive species (including biological mercaptan). The probe SG-H 2 S has low cytotoxicity and has been successfully applied to imaging in MCF-7 cells, HeLa cells, and BALB/c nude mice. We hope that SG-H 2 S will provide a vital method for the field of biology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen polysulfide (H 2 S n , n≥2), as a kind of active sulfur species (RSS), has become a hot topic in RSS. It can regulate the biological activity of many proteins through S-sulfhydrylation of cysteine residues (protein Cys-SSH), and has a protective effect on cells. Although there have been some studies on hydrogen polysulfide, its production, degradation pathway and regulation mechanism still need further be researched. In presented study, an original lysosome-localized fluorescent probe for determining H 2 S n was developed utilizing rhodamine as the fluorogen. The probe used morpholine as the locating unit of lysosomes and chose 2-fluoro-5-nitrobenzoate as the recognizing group. Before adding H 2 S n , the proposed probe displayed a spironolactone structure and emitted very weak fluorescence. After adding H 2 S n , a conjugated xanthene was formed and the probe demonstrated green fluorescence. When the H 2 S n concentration was varied from 6.0×10 -7 mol·L -1 to 10.0×10 -5 mol·L -1 , the fluorescence intensity of the probe was linearly dependent on the H 2 S n concentration. And the detection limit was 1.5×10 -7 mol·L -1 . The presented probe owned a fast response speed, good selectivity, excellent sensitivity and broad pH work scope. In addition, the probe had been well utilized to sense endogenic and exogenic H 2 S n in lysosomes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The colorimetric point-of-care test (POCT) offers a rapid and efficient method for detecting specific targets in real samples. However, traditional colorimetric methods often rely on complex signal amplification techniques or electronic devices to enhance detection sensitivity, which can inadvertently increase both cost and time, thus contradicting the fundamental goals of visual detection methods. Here, we presented a distance-based fluorescent immunosensor that utilized a gas-producing nanozyme for continuous gas production reaction as a signal. Specifically, the SOM-ZIF-8@Pt nanozyme catalyzed the production of O 2 from H 2 O 2 to cause an obvious increase in the pressure within a sealed chamber, thus driving the production of H 2 S to quench the fluorescence of CsPbBr 3 on the walls of the capillaries. Based on the competitive immunoassay, the fluorescence quenching lengths were relative with the concentration of aminopyrine in the range from 0.2 to 20 ng/L; thus, the fluorescent POCT-based homemade device was realized through the amplification of distance-based signals facilitated by the continuous gas production reaction. This strategy provides an effective way to realize POCT assays in resource-limited areas by transforming pressure variations into directly observable signals. Furthermore, distinguished by its high sensitivity, ease of operation, and portability, it also represents a significant advancement in biomedical diagnostics, particularly within home healthcare and clinical POCT.

Although composting has many advantages in treating organic waste, many problems and challenges are still associated with emissions, like NH 3 , CO and H 2 S, as well as greenhouse gases such as CO 2 . One promising approach to enhancing composting conditions is using novel analytical methods based on artificial intelligence. To predict and optimize the emissions (CO, CO 2 , H 2 S, NH 3 ) during the early-stage of composting process machine learning (ML) models were utilized. Data about emissions from laboratory composting with compost's biochar with different incubation (50, 60, 70 °C) and biochar doses (0, 3, 6, 9, 12, 15% dry mass) were used for ML models selections and training. ML models such as acritical neural network (ANN, Bayesian Regularized Neural Network; R 2 accuracy CO:0.71, CO 2 :0.81, NH 3 :0.95, H 2 S:0.72) and decision tree (DT, RPART; R 2 accuracy CO:0.69, CO 2 :0.80, NH 3 :0.93, H 2 S:0.65) have demonstrated satisfactory results. The ML models to predict CO and H 2 S during composting were demonstrated for the first time. Utilizing emission data to predict other noxious gases presents a cost-effective and expeditious alternative to the empirical analysis of compost properties., (© 2024. The Author(s).)

Reactive sulfur species (RSS) including persulfides (RSSHs), biothiols, and hydrogen sulfide (H 2 S) are key regulators in various physiological processes. To better understand the symbiotic relationship and interconversion of these RSS, it is highly desirable but challenging to develop analytical techniques that are capable of detecting and quantifying them. Herein, we report the rational design and synthesis of novel trityl-radical-based electron paramagnetic resonance (EPR) probes dubbed CT02-TNB and OX-TNB. CT02-TNB underwent fast sulfur exchange reactions with two reactive RSSHs (PS1 and PS2) which were released from their corresponding donors PSD1 and PSD2 to afford the specific conjugates. The resulting conjugates exhibit characteristic EPR spectra, thus enabling discriminative detection and quantitation of the two RSSHs. Moreover, CT02-TNB showed good response toward other RSS including glutathione (GSH), cysteine (Cys), H 2 S, and sulfite as well. Importantly, based on the updated EPR spectral simulation program, simultaneous quantitation of multiple RSS (e.g., PS1/GSH/Cys or PS1/GSH/H 2 S) by CT02-TNB was also achieved. Finally, the levels of released PS1 from PSD1 and endogenous GSH in isolated mouse livers were measured by the hydrophilic OX-TNB. This work represents the first study achieving discriminative and quantitative detection of different persulfides and other RSS by a spectroscopic method.

Hydrogen sulfide (H 2 S) is a critical bioregulator implicated in numerous physiological and pathological processes, including cancer and neurodegenerative diseases. Compared with traditional instrument analysis, fluorescence detection technology based on small molecules in real-time and in situ sensing H 2 S has attracted attention. In this investigation, we developed a system of coumarin-based fluorophores linked with aminopyridine via a dipolar imino-double bond. Their aggregation-induced emission (AIE) behaviors were further regulated via structural isomerism engineering. Owing to restricting intramolecular motions and high molecular dipole moment, 2-amino-pyridyl-substituted coumarin (CMR- o -Py) forms stable AIE nanoaggregates with brighter fluorescence than the others. The CMR- o -Py nanoaggregates serve as probes for sensing H 2 S with a detection limit of 18.1 μM in a hydrophilic environment via Michael addition between imino-bond and sulfide ions. The 1 : 1 stoichiometric binding energy constant between the probe and H 2 S is 5.68 × 10 8 M -1 , and its half-time of the first-order binding reaction was estimated to be 4.85 min. Moreover, CMR- o -Py, with excellent biocompatibility, holds promise as an ideal sens o r for endogenous H 2 S in living cells and onion tissues, further highlighting its potential application in biological fields.

Hydrogen sulfide (H 2 S) is a pungent gas that is one of the key mediators of signal transduction in biological systems, and its presence is related to the freshness of some protein foods. Using phenothiazine derivatives as fluorophores and 2, 4-dinitrobenzene sulfonate (DNBS) fragments as reaction groups, a near-infrared (NIR) probe WX-HS for H 2 S identification was designed. With the addition of H 2 S, WX-HS appeared a strong fluorescence signal at 660 nm with short reaction time (90 s) and high sensitivity, and fluorescence state change from non-fluorescent to orange-red. In addition, WX-HS could effectively detect H 2 S produced during food oxidation. Based on its low cytotoxicity, the WX-HS probe further enabled the detection and imaging of H 2 S in A549 cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The combination of bio-imaging with photodynamic therapy (PDT) to accomplish theranostics is promising in cancer treatment. Three chitosan-naphthalimide probes were studied in this work. 4-(5-Bromothiophen-2-yl)-1,8-naphthalic anhydride was first synthesized, and then reacted with chitosan to obtain the macromolecules (CS-N-Br). The recognition group thiomorpholine or its derivatives were introduced into CS-N-Br to obtain nano-probes (CS-N-ML, CS-N-BSZ, CS-N-FSQ) eventually. The studies revealed that CS-N-ML and CS-N-FSQ exhibit high selectivity and can specifically recognize HClO and H 2 S. CS-N-ML and CS-N-FSQ can perform exogenous and endogenous confocal imaging of HClO and H 2 S in cells also. CS-N-ML's ability to target lysosomes positions indicated it could act as a lysosome-specific probe. It was discovered that the probes generate superoxide anions (O 2 •- ) via a Type I mechanism. This discovery endows the probes with high photosensitizing activity even under hypoxic conditions. There is a positive correlation between the extent of the conjugated system and the photosensitivity of the probes, indicating that an enhanced conjugation leads to increased photosensitivity. Upon light irradiation, the probes generate ROS within HeLa cells. These results suggested that these probes can achieve theranostics for diseases associated with abnormal levels of HClO and H 2 S., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Xinjian cheng, phd reports financial support was provided by National Natural Science Foundation of China. No reports a relationship with no that includes:. No has patent no pending to no. The authors, Bo Zhao, Jun Liu, Caiqiong Zhu, and Xinjian Cheng, declare there is no any competing financial interest. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

As a representative gas of food spoilage, the development of rapid hydrogen sulfide (H 2 S) analysis strategies for food safety control is in great demand. Despite traditional methods for H 2 S detection possessing great achievements, they are still incapable of meeting the requirement of portability and quantitative detection at the same time. Herein, a nanozyme catalysis pressure-powered sensing platform that enables visual quantification with the naked eye is proposed. In this methodology, Pt nanozyme inherits the catalase-like activity to facilitate the decomposition of H 2 O 2 to O 2 , which can significantly improve the pressure in the closed container, further pushing the movement of indicator dye. Furthermore, H 2 S was found to effectively inhibit the catalytic activity of Pt nanozyme, indicating that the catalase-like activity of PtNPs may be regulated by varying concentrations of H 2 S. Therefore, by utilizing a self-designed pressure-powered microchannel device, the concentration of H 2 S was successfully converted into a distinct signal variation in distance. The effectiveness of the as-designed sensor in assessing the spoilage of red wine by H 2 S determination has been demonstrated. It exhibits a strong correlation between the change in dye distance and H 2 S concentration within the range of 1-250 μM, with a detection limit of 0.17 μM. This method is advantageous as it enhances the quantitative detection of H 2 S with the naked eye based on the portable pressure-powered sensing platform, as compared to traditional H 2 S biosensors. Such a pressure-powered distance variation platform would greatly broaden the application of H 2 S-based detection in food spoilage management., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

A simple, selective, and affordable dual fluorescence-colorimetric indicator for hydrogen sulfide was developed based on a complex of copper nanoparticles and N-doped carbon quantum dots (CuNPs/NCQDs). Real-time and visual freshness tracking of fish was done using a colorimetric indicator by incorporating CuNPs/NCQDs into agar hydrogel (AH-CuNPs/NCQDs). The fluorescence response of the CuNPs/NCQDs solution is quenched upon exposure to H 2 S. The field-emission scanning electron microscopy image of the AH-CuNPs/NCQDs film revealed a unified structure. The prepared indicator exhibited a good and irreversible response to H 2 S, with a LOD of 91.36 and a LOQ of 276.86 μM, based on the localized surface plasmon resonance (LSPR) mechanism. The X-ray photoelectron spectrometer and Fourier transform infrared spectrometer results confirmed the formation of a CuS bond in the colorimetric indicator exposed to fish spoilage. The prepared indicator demonstrated good stability and remained unaffected by pH or other volatile compounds. Notably, there was a strong correlation between ΔΕ and fish freshness parameters (pH, TV-BN, and TVC). Light green, pale yellow, and dark yellow colors, respectively, indicated freshness, semi-freshness, and spoilage of fish during storage in the refrigerator. Overall, the prepared indicator can be effectively used for detecting spoilage in meat products as a highly sensitive freshness indicator., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest related to this research. We certify that we have no financial or personal relationships with individuals or organizations that could inappropriately influence or bias our work., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

To address the serious waste of meat resources and food safety problems caused by the decrease in meat freshness due to the action of microorganisms and enzymes, a low-cost, time-saving and high-efficiency freshness monitoring method is urgently needed. Fluorescence sensing could act as a "magnifier" for meat freshness monitoring due to its ability to sense characteristic signal produced by meat spoilage. Here, the magnification mechanism of meat freshness via sensing the water activity, adenosine triphosphate, hydrogen ion, total volatile basic nitrogen, hydrogen sulfide, bioamines was comprehensively analyzed. The existing "magnifier" forms including paper chips, films, labels, arrays, probes, and hydrogels as well as the application in livestock, poultry and aquatic meat freshness monitoring were reviewed. Future research directions involving innovation of principles, visualization and quantification capabilities for various meats freshness were provided. By critically evaluating the potential and limitations, efficient and reliable meat freshness monitoring strategies wish to be developed for the post-epidemic era.

The significance of hydrogen sulfide (H 2 S) as a crucial gasotransmitter has been shown extensively in plants, and endogenous H 2 S is often modulated to activate H 2 S signaling when plants respond to numerous developmental and environmental cues. Consequently, elucidating the H 2 S physiological concentrations and the H 2 S generation intensity of plants is key to understanding the activation mechanism of H 2 S signaling, which has attracted increasing attention. Currently, a variety of reaction-based methods have been reported for monitoring H 2 S concentration in vivo and in vitro. In this review, we summarize and describe in detail several methods for quantifying and bioimaging endogenous H 2 S in plants systems, mainly the spectrophotometer-dependent methylene blue (MB) method and fluorescence probes, including the reaction mechanisms, design strategies, response principles, and application details. Moreover, we also summarize the advantages and disadvantages of these methods as well as the research scenarios in which they are applicable. We expect that this review will provide some guidelines on the selection of methods for H 2 S sensing and the comprehensive investigations into H 2 S signaling in plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Detecting hydrogen sulfide (H 2 S) odor gas in the environment at parts-per-billion-level concentrations is crucial. However, a significant challenge is the rapid deactivation caused by SO 4 2- deposition. To address this issue, we developed a sensing material comprising Fe 2 O 3 -decorated WO 3 nanowires (FWO) with strong interfacial interaction. During the H 2 S sensing process, important oxygen vacancies (OVs) are generated in situ and are recyclable on the surface of the Fe 2 O 3 cluster. This sensor achieves a response of 140 (Ra/Rg) toward 50 ppm of H 2 S at 250 °C, with an experimentally measured detection limit of 1 ppb. It also exhibits remarkable stability, with no significant change observed over a long period of 150 days. Based on a combination of in situ DRIFT and DFT calculations, we have identified that the overactivation of O 2 is the key step in the formation of SO 4 2- . This overactivation can be partially modulated by the synergistic effect of Fe 2 O 3 decoration and the in situ generated OVs, regulating the oxidation product to SO 2 rather than the toxic SO 4 2- . Furthermore, the continuous generation of OVs compensates for the loss of active sites pertaining to SO 4 2- deposition, thereby contributing to the excellent stability of the sensor. This study underscores the beneficial impact of in situ OV generation in FWO for H 2 S sensing, offering a dynamic strategy to enhance sensor performance, particularly in terms of stability.

Loading a sensitizer and constructing a rational nanostructure have been reported to be effective approaches for enhancing the catalytic/sensing performance. However, the impact of the precise loading position on the catalytic/sensing performance is always overlooked. Here, we discovered that precisely changing the location of Pt clusters from the outside of Al 2 O 3 -ZnO nanocoils (O-PtAlZnNCs) to the inner side of the nanocoils (I-PtAlZnNCs) could change the sensing performance of the sensor from H 2 S to acetone. Furthermore, precisely loading Pt inside of the confined space led to a high sensing performance and reduced the limit of detection (LOD) of acetone by a factor of 50 times (from 100 to 2 ppb). Combining X-ray photoelectron spectroscopy (XPS), NH 3 -diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), in situ X-ray absorption spectroscopy (XAS), and density functional theory (DFT) simulations, the enhancement of sensitivity and regulation of sensing selectivity are attributed to the coupling effects from enrichment of confined space and Al 2 O 3 acid-base active sites as well as the regulation of electronic structure by location-dominated strain effects. This work not only provides a novel sight to precisely regulate the selectivity and obtain ultrasensitive materials but also serves as a useful instruction for further understanding and precisely designing specific sensors and catalysts with high performance.

Carbon nanotubes (CNTs) had room temperature response, large surface area, and excellent mechanical properties, making them favorable for the design of flexible, wearable, and portable gas sensors. However, CNTs were lacking in response and selective response to different gases, such as H 2 S. Here, we demonstrated a flexible H 2 S ppb-level gas sensor based on a carbon nanotube/amorphous Fe 2 O 3 (CNT/Fe 2 O 3 ) film at room temperature, which was fabricated via a simple one-step solvent-thermal method. The CNT/Fe 2 O 3 film gas sensor exhibited a high selective response to H 2 S (with a response of 55.1% to 100 ppb H 2 S), rapid reversible response at room temperature (with a response time of ∼127 s to 100 ppb H 2 S), and low limit of detection to about 2 ppb. Additionally, the CNT/Fe 2 O 3 film maintained good sensing performance under various bending conditions and could be further fabricated into the fiber gas sensor device via wet stretching, retaining response at the ppb level (with a response of 18.6% to 100 ppb H 2 S). This research on a flexible gas sensor device based on the CNT film/fiber opened up new possibilities for wearable portable electronic device applications.

Detecting H 2 S in oxygen-deficient conditions is vital for identifying leaks in SF 6 -insulated electrical equipment. Current infrared-based detection methods are expensive and sensitive to environmental conditions, highlighting the necessity for cost-effective and stable gas sensors. Existing gas sensors based on semiconducting metal oxides (SMOXs) are limited by redox reactions with oxygen and require high operating temperatures. Here, we introduce a room-temperature (RT) H 2 S sensor for oxygen-deficient environments using the intrinsic conducting two-dimensional (2D) metal-organic framework (MOF), Co 1.8 Ni 1.2 (hexaiminotriphenylene) 2 [Co 1.8 Ni 1.2 (HITP) 2 ], overcoming the limitations of SMOX gas sensors. Remarkably, Co 1.8 Ni 1.2 (HITP) 2 sensors exhibit exceptional selectivity for H 2 S with negligible cross-responses and a sensitivity drift of less than 4.13% in an SF 6 atmosphere over 60 days. The Co 1.8 Ni 1.2 (HITP) 2 gas sensor shows significant promise for real-time and stable monitoring of H 2 S gas in oxygen-deficient environments.

Wastewater treatment plants (WWTPs) are major sources of volatile gaseous compounds, especially in mixed-source systems such as domestic wastewater and landfill leachate. This study aimed to investigate the emission behavior and environmental impact of gaseous substances, such as hydrogen sulfide (H 2 S), ammonia (NH 3 ), carbon sulfide (CS 2 ), and phosphine (PH 3 ), at a WWTP in Northwest China. Odorants were detected in the air surrounding the grid room (XGS), biochemical treatment tank (SHC), secondary sedimentation tank (ECC), and sludge dewatering room (NTS). For comparison, the upwind boundary (O-SF) and downwind boundaries (O-XF) monitoring points were used, with odor concentrations ranging from 3.95 to 725.27 odor units. The concentration ranges of the odorant substances were 5.27-88.69, 5.61-71.96, 5.70-32.63, and 0.12-5.87 mg/m 3 for H 2 S, NH 3 , CS 2 , and PH 3 , respectively. Meteorological factors such as temperature, relative humidity, and wind speed and direction substantially influence odorant emissions. The concentrations of various odorants and volatile organic compounds (VOCs) detected at the O-XF monitoring point were higher than those detected at the O-SF monitoring point, indicating that the wind intensified their diffusion toward the downwind plant boundary. The average odor intensities of odorant substances emitted from wastewater or sludge treatment equipment were 3.37, 5.09, 4.42, 2.00, and 3.82 for total VOCs, H 2 S, NH 3 , CS 2 , and PH 3 , respectively. Among them four, with downwind diffusion, only H 2 S presented olfactory and chronic toxicity risks based on Gaussian plume model calculations. The hazard index ranking across monitoring sites was XGS > NTS > SHC > ECC > O-XF > O-SF. These findings emphasize the urgent need for effective measures to control and mitigate gaseous pollutants emitted by collaborative WWTPS, thereby protecting environmental quality and public health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this study, we present an innovative "click-to-release" strategy for the design of highly specific H 2 S n bioorthogonal probes that undergo a specific click reaction with H 2 S n and release fluorophores by a following rearrangement. A library of cyclooctyne derivatives was established and successfully demonstrated the availability of the release strategy. Then, a model probe CM-CT was synthesized, which can achieve effective fluorophore release (>80%) in the presence of a H 2 S n donor. To further validate the application of this class of probes, a new probe QN-RHO-CT based on Rhodamine 110 was developed. This probe showed good water solubility (>160 μM) and fast release kinetics and can achieve selective H 2 S n detection in living cells. We used this probe to study the process of H 2 S-mediated protein S-persulfidation and demonstrated that excess H 2 S would directly react with protein persulfides to generate H 2 S 2 and reduce the persulfides to thiols. Additionally, we elucidated the click-to-release mechanism in our design through a detailed mechanistic study, confirming the generation of the key intermediate α, β-unsaturated cyclooctanethione. This bioorthogonal click-to-release reaction provides a useful tool for investigating the function of H 2 S n and paves the way for biological studies on H 2 S n .

Although semiconductor metal oxide-based sensors are promising for gas sensing, low-power and room temperature operation (24 ± 1 °C) remains desirable for practical applications particularly considering the request of energy saving or net zero emission. In this study, we demonstrate a Au/SnO 2 -based ultrasensitive H 2 S gas sensor with a limit of detection (LOD) of 2 ppb, operating at very low voltages (0.05 to 0.5 V) at room temperature. The Au/SnO 2 -based sensor showed approximately 7 times higher response (the ratio of change in the current to initial current) of ∼270% and 4 times faster recovery (126 s) compared to the pure SnO 2 -based sensor when exposed to 500 ppb H 2 S gas concentration at 0.5 V operating voltage at relative humidity (RH) 17.5 ± 2.5%. The enhancement can be attributed to the catalytic characteristics of AuNPs, increasing the number of adsorbed oxygen species on sensing material surfaces. Additionally, AuNPs aid in forming flower-petal-like Au/SnO 2 nanostructures, offering a larger surface area and more active sites for H 2 S sensing. Moreover, at low voltage (<1 V), the localized dipoles at the Au/SnO 2 interface may further enhance the absorption of polar oxygen molecules and hence promote the reaction between H 2 S and oxygen species. This low-power, ultrasensitive H 2 S sensor outperforms high-powered alternatives, making it ideal for environmental, food safety, and healthcare applications.

Hydrogen sulfide (H 2 S) has emerged as a significant biomolecule with diverse activities, akin to other gaseous signaling molecules such as nitric oxide (NO) and carbon monoxide (CO). In the present study, we report on the development of esterase-activated donors that track their direct cellular donation of H 2 S by enlisting a cyclization reaction onto a thioamide that forms a fluorogenic byproduct. This simple donor design provides a noninvasive method for monitoring the biological delivery and activity of H 2 S, along with access to a library of compounds with highly variable rates of H 2 S delivery. These studies culminated with the identification of a slow-release, yet highly efficient, donor ( ZL-DMA-Ph ) that was shown to self-report its gradual and continuous cellular donation of H 2 S for up to 24 h which, in addition to better mimicking the natural biosynthesis of H 2 S, provided impressive cytoprotection in a cellular cardiotoxicity model, even at submicromolar concentrations. In total, these findings indicate that the esterase-triggered fluorogenic donors identified in this study will offer new opportunities for exploring the chemical biology and therapeutic potential of exogenous H 2 S supplementation.

Metformin (MET) is currently the first-line treatment for type 2 diabetes mellitus (T2DM). However, overdose and long-term use of MET may induce a serious liver injury. What's worse, diagnosis of MET-induced liver injury remains challenging in clinic. Although several probes have been reported for imaging MET-induced liver injury utilizing upregulated hepatic H 2 S as a biomarker, they are still at risk of nonspecific activation in complex physiological environments and rely on light excitation with limited imaging depth. Herein, we rationally designed and developed a dual-locked probe, DPA-H 2 S, for precise imaging of MET-induced liver injury by H 2 S-activated sonoafterglow luminescence. DPA-H 2 S is a small molecule consisting of a sonosensitizer protoporphyrin IX (PpIX) and an afterglow substrate that is dual-locked with a H 2 S-responsive 2,4-dinitrobenzene group and a 1 O 2 -responsive electron-rich double bond. When employing DPA-H 2 S for imaging of MET-induced liver injury in vivo , since the PpIX moiety can produce 1 O 2 in situ at the liver site under focused ultrasound (US) irradiation, the two locks of DPA-H 2 S can be specifically activated by the highly upregulated H 2 S at the liver injury sites and the in situ generated 1 O 2 , respectively. Thus, the sonoafterglow signal of DPA-H 2 S is significantly turned on, enabling precise imaging of the MET-induced liver injury. In vitro results showed that, through H 2 S-activated sonoafterglow luminescence, DPA-H 2 S was capable of imaging H 2 S with good sensitivity and high selectivity and realized deep tissue imaging (∼20 mm, signal-to-background ratio (SBR) = 3.4). Furthermore, we successfully applied DPA-H 2 S for precise in vivo imaging of MET-induced liver injury. We anticipate that our dual-locked probe, DPA-H 2 S, may serve as a promising tool in assisting the diagnosis of MET-induced liver injury in clinics and informing the clinical utilization of MET in the near future.

Studies on the interaction between hydrogen sulfide (H 2 S) and hydrogen peroxide (H 2 O 2 ) in redox signaling motivate the development of a sensitive sensing platform for their discriminatory and dynamic detection. Herein, we present a fully integrated microfluidic on-chip electrochemical sensor for the online and simultaneous monitoring of H 2 S and H 2 O 2 secreted by different biological samples. The sensor utilizes a cicada-wing-like RuCu bimetal-organic framework with uniform nanorods architecture that grows on a flexible carbon fiber microelectrode. Owing to the optimized electronic structural merits and satisfactory electrocatalytic properties, the resultant microelectrode shows remarkable electrochemical sensing performance for sensitive and selective detection of H 2 S and H 2 O 2 at the same time. The result exhibits low detection limits of 0.5 μM for H 2 S and 0.1 μM for H 2 O 2 , with high sensitivities of 61.93 μA cm -2 mM -1 for H 2 S, and 75.96 μA cm -2 mM -1 for H 2 O 2 . The integration of this biocompatible microelectrode into a custom wireless microfluidic chip enables the construction of a miniature intelligent system for in situ monitoring of H 2 S and H 2 O 2 released from different living cells to differentiate between cancerous and normal cells. When applied for real-time tracking of H 2 S and H 2 O 2 secreted by colorectal cancer tissues, it allows the evaluation of their chemotherapeutic efficacy. These findings hold paramount implications for disease diagnosis and therapy., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, services and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen sulfide (H 2 S) is a gaseous signaling molecule that regulates various physiological and pathological processes in the central nervous system. It is vital to develop an effective method to detect H 2 S in vivo to elucidate its critical role. However, current fluorescent probes for accurate quantification of H 2 S still face big challenges due to complicated fabrication, small Stokes shift, unsatisfactory selectivity, and especially delayed response time. Herein, based on simple postsynthetic modification, we present an innovative strategy by confining H 2 S-triggered thiolysis of dinitrophenyl (DNP) ether within a luminescent metal-organic framework (MOF) to address those issues. Due to the cleavage of the DNP moiety by H 2 S, the nanoprobe gives rise to a remarkable fluorescence turn-on signal with a large Stokes shift of 190 nm and also provides high selectivity to H 2 S against various interferents including competing biothiols. In particular, by virtue of the unique structural property of the MOF, it exhibits an ultrafast sensing ability for H 2 S (only 5 s). Moreover, the fluorescence enhancement efficiency displays a good linear correlation with H 2 S concentration in the range of 0-160 μM with a detection limit of 0.29 μM. Importantly, these superior sensing performances enable the nanoprobe to measure the basal value and monitor the change of H 2 S level in the rat brain.

In several biological processes, H 2 S is known to function as an endogenous gaseous agent. It is very necessary to monitor H 2 S and relevant physiological processes in vivo. Herein, a new type of fluorophore with a reliable leaving group allows for excited-state intramolecular transfer characteristics (ESIPT), inspired by mycophenolic acid. A morpholine ring was connected at the maleimide position of the probe to target the lysosome. Subsequently, the dinitrophenyl group known for a photoinduced electron transfer (PET) effect, was connected to allow for an effective "turn-on" probe Lyso-H 2 S. Lyso-H 2 S demonstrated strong selectivity towards H 2 S, a large Stokes shift (111 nm), and an incredibly low detection limit (41.8 nM). The imaging of endogenous and exogenous H 2 S in living cells (A549 cell line) was successfully achieved because of the specificity and ultra-low toxicity (100 % cell viability at 50 μM concentration of Lyso-H 2 S.) Additionally, Lyso-H 2 S was also employed to visualize the activity of H 2 S in the gallbladder and intestine in a living zebrafish model. This is the first report of a fluorescent probe to track H 2 S sensing in specific organ systems to our knowledge., (© 2024 Wiley-VCH GmbH.)

Hydrogen sulfide (H 2 S) is a poisonous pollutant that endangers the environment, and H 2 S is also produced during food spoilage. Herein, we constructed a dicyanoisophorone-based near-infrared (NIR) fluorescent probe (DCID) to detect H 2 S. DCID exhibited significant turn-on fluorescence at 700 nm with a low limit of detection (LOD = 74 nM), large Stokes shift (220 nm), prominent selectivity, and response time (100 s) toward H 2 S. Importantly, the DCID probe had powerful applications in the detection of H 2 S in environmental samples and food spoilage. In addition, based on DCID-loaded test strips and combined a smartphone sensing platform, which provided a portable and convenient approach for the detection of H 2 S., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A novel flavonol-based fluorescent probe, Fla-DNT, has been synthesized for the rapid and specific detection of H 2 S. Fla-DNT exhibits excellent selectivity and anti-interference properties, a short response time (4 min), large Stokes shift (138 nm), and low detection limit (1.357 µM). Upon exposure to H 2 S, Fla-DNT displays a remarkable increase in fluorescence intensity at 542 nm. Meanwhile, the recognizing site of H 2 S was predicted through Electrostatic potential and ADCH charges calculations, while the sensing mechanism of H 2 S was determined via HRMS analysis and DFT calculation. More importantly, the probe owes multiple applications, such as a recovery rate ranging from 92.00 to 102.10% for detecting H 2 S in water samples, and it can be fabricated into fluorescent strips to track H 2 S production during food spoilage by tracking color changes, thereby enabling real-time monitoring of food freshness. The bioimaging experiments demonstrate the capability of Fla-DNT to detect both endogenous and exogenous H 2 S in living cells. These results provide a reliable method and idea for H 2 S detection in complex environments., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Periodontitis, a chronic disease, can result in irreversible tooth loss and diminished quality of life, highlighting the significance of timely periodontitis monitoring and treatment. Meanwhile, hydrogen sulfide (H 2 S) in saliva, produced by pathogenic bacteria of periodontitis, is an important marker for periodontitis monitoring. However, the easy volatility and chemical instability of the molecule pose challenges to oral H 2 S sensing. Here, we report a wearable hydrogel-based radio frequency (RF) sensor capable of in situ H 2 S detection and antibacterial treatment. The RF sensor comprises an agarose hydrogel containing conjugated silver nanoparticles-chlorhexidine (AG-AgNPs-CHL hydrogel) integrated with split-ring resonators. Adhered to a tooth, the hydrogel-based RF sensor enables wireless transmission of sensing signals to a mobile terminal and a concurrent release of the broad-spectrum antibacterial agent chlorhexidine without complex circuits. With the selective binding of the AgNPs to the sulfidion, the RF sensor demonstrates good sensitivity, a wide detection range (2-30 μM), and a low limit of detection (1.2 μM). Compared with standard H 2 S measurement, the wireless H 2 S sensor can distinguish periodontitis patients from healthy individuals in saliva sample tests. The hydrogel-based wearable sensor will benefit patients with periodontitis by detecting disease-related biomarkers for practical oral health management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen sulfide is a vital signaling molecule which holds a pivotal position in numerous biological functions. In this research, two novel "OFF-ON" fluorescence probes named YNO and TNO were designed based on the nitroso recognition group to detect H 2 S. Both YNO and TNO performed outstanding response rate and linear relationship between the fluorescence intensity and the concentration of H 2 S. YNO possessed larger Stokes shift and longer emission wavelength. TNO had lower limit of detection. In addition, YNO was successful applied to sense endogenous and exogenous H 2 S and target endoplasmic reticulum (ER) in Hela cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Multifunctional type-I photosensitizers (PSs) for hydrogen sulfide (H 2 S) detection and photodynamic therapy (PDT) of hypoxia tumors exhibits attractive curative effect but remains a challenging task. Herein, a mitochondria targeted aggregation-induced emission (AIE) photosensitizer TSPy-SS-P was designed and synthesized, which could be used for H 2 S detection and simultaneously type I and type II PDT. TSPy-SS-P had excellent selectivity and anti-interference abilities for endogenous and exogenous H 2 S detection in tumor cells. TSPy-SS-P was able to distinguish tumor cells with high level of H 2 S from normal cells by fluorescence "turn off" response to H 2 S. In addition, TSPy-SS-P showed type Ⅰ and type Ⅱ reactive oxygen species (ROS) generation ability to effectively ablate hypoxic tumor cells. TSPy-SS-P showed mitochondria targeting capacity which could produce ROS in situ to disrupt mitochondria and promote cell apoptosis. In vivo PDT experiments showcased that TSPy-SS-P had excellent tumor retention capability, effective tumor ablation ability and good biocompatibility. This work provided a two-pronged strategy to design organelles targeted photosensitizers for H 2 S detection and effective PDT of tumors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Accurate modeling of methane (CH 4 ) and sulfide (H 2 S) production in sewer systems was constrained by insufficient consideration of microbial processes under dynamic environmental conditions. This study introduces a microbial-guided machine learning (ML) framework (Micro-ML), which integrates microbial process representations from mechanistic models (microbial information) with ML models. Results indicate that Micro-ML model enhanced predictions of CH 4 and H 2 S production, where microbial information provides more information for model optimization. The feature importance of microbial information performed comparable weightings for 58.12 % and 55.16 %, respectively, but their relative significance in influencing Micro-ML model performance varies considerably. The application of Micro-ML performed great potential in reducing CH 4 and H 2 S production (decreased ∼ 80 % and 90 %). The integrated model not only improves the accuracy of CH 4 and H 2 S predictions but also offers a valuable tool for effective management strategies for sewer systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this study, the N-Acetyl-l-Cysteine (NAC)-capped gold and silver bimetallic nanoclusters (NAC@Au-Ag NCs) was synthesized by reflux method. Due to the silver effect, the NAC@Au-Ag NCs exhibited strong photoluminescence at far-red/near-infrared regions and better catalytic performance than Au or Ag NCs. Upon addition of H 2 S, the Au-Ag NCs exhibited obvious fluorescence quench and color changes through the generation of metal sulfides and a static quenching process. The Au-Ag NCs displayed a wide linear luminescence response for H 2 S (18.5-217 μmol/L) with a detection limit of 0.269 μmol/L. Moreover, the visible color of Au-Ag NCs changed from white to brown-yellow along with increased H 2 S, the corresponding RGB values also displayed good linearity with the concentration of H 2 S (90.1-678 μmol/L). Notably, the fabrication of test strips provided a convenient and intuitive tool to screen the freshness of eggs by the color change of test strips. Au-Ag NCs could be used for living HeLa cells bioimaging and recognition of H 2 S abnormalities. Furthermore, it can be used as a catalyst to reduction of nitrophenols (NPhs), specific included 2NP, 3NP and 4NP. The reaction was regarded as a pseudo-first-order kinetic reaction due to the presence of excess NaBH 4 . At 298K, the catalytic rate constants(k) of 2NP, 3NP and 4NP were 0.1754 min -1 , 0.1734 min -1 and 0.2782 min -1 , respectively. The NAC@Au-Ag NCs catalyst still showed good catalytic activity and reusability after five cycles. Therefore, this study developed a H 2 S sensor for food samples and biological systems. And this nanocatalyst had great application potential for removed the nitrophenol pollutants in water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen sulfide (H 2 S) has emerged as a crucial signaling molecule in plant stress responses, playing a significant role in regulating various physiological and biochemical processes. In this study, we report an aggregation-induced emission (AIE)-based ratiometric fluorescent probe TPN-H 2 S for the highly selective detection of H 2 S in plant tissues. The probe exhibited excellent sensitivity and selectivity towards H 2 S over other analytes, enabling real-time monitoring of H 2 S dynamics in living cell. Furthermore, the AIE-based ratiometric probe TPN-H 2 S allowed for accurate quantification of H 2 S levels, providing valuable insights into the spatiotemporal distribution of Cys metabolism produces H 2 S. Importantly, the physiological pathways and signaling mechanisms of H 2 S production of was investigated in plant tissues under Cr and nano-plastics stress. Utilizing a high-throughput screening approach, we identified exogenous substances such as calcium chloride (CaCl 2 ) and abscisic acid (ABA) that could induce higher level of H 2 S production during the stress response in plants. Overall, those findings demonstrate the potential of the AIE-based ratiometric fluorescent probe TPN-H 2 S as a powerful tool for unraveling the role of H 2 S in plant stress responses and pave the way for further exploration of H 2 S-mediated signaling pathways in plants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen sulfide (H 2 S) is implicated in numerous physiological and pathological processes in living organisms. Abnormal levels of H 2 S can result in various physiological disorders, highlighting the crucial need for effective identification and detection of H 2 S at the organellar level. Although numerous H 2 S fluorescent probes targeting organelles have been reported, a comprehensive review of these probes is required. This review focuses on the strategic selection of organelle-targeting groups and recognition sites for H 2 S fluorescent probes. This review examines H 2 S fluorescent probes that can specifically target lysosomes, mitochondria, endoplasmic reticulum, Golgi apparatus, and lipid droplets. These fluorescent probes have been meticulously classified and summarized based on their distinct targets, emphasizing their chemical structure, reaction mechanisms, and biological applications. We carefully designed fluorescent probes to efficiently enhance their ability to recognize target substances and exhibit significant fluorescence variations. Furthermore, we discuss the challenges inherent in the development of fluorescent probes and outline potential future directions for this exciting field., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Quantitatively and selectively detecting the biomarker of hydrogen sulfide (H 2 S) in arthritis diseases is of great significance for the early diagnosis and treatment of arthritis. Modern medical studies show that H 2 S as a biomarker is involved in the development of inflammation. In this work, a new highly specific fluorescence "turn-on" probe JMD-H 2 S was tailored for H 2 S detection and imaging in drug-induced live cells, zebrafish and mice arthritis models, which utilized pyrazoline molecule as the fluorescence signal reporter group and 2,4-dinitrophenyl ether group (DNB) with strong intramolecular charge transfer (ICT) effect as the H 2 S recognition moiety and fluorescence quenching group. JMD-H 2 S showed a fast response time (<60 s), a large fluorescence response ratio (enhanced ∼20 folds) at I 453 /I 0 , excellent sensitivity toward H 2 S over other analytes, and an outstanding limit of detection (LOD) as low as 25.3 nM. In addition, JMD-H 2 S has been successfully applied for detecting and imaging H 2 S in drug-induced live cells, zebrafish, and mice arthritis models with satisfactory results, suggesting it can be used as a robust molecular tool for investigating the occurrence and development of H 2 S and arthritis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen sulfide (H 2 S) can act as a gaseous signaling mediator closely associated with inflammation development. In this work, we designed a fluorescence turn-on near-infrared (NIR) fluorescent probe CIT-H 2 S based on Intermolecular Charge Transfer (ICT) for the detection of H 2 S in living inflammatory cells and zebrafish. On this basis, a dicyanoisophorone fluorophore was chosen as the fluorescence signal reporting group of CIT-H 2 S, and an azide group was constructed as the recognition group of H 2 S. CIT-H 2 S is characterized by high selectivity and sensitivity for H 2 S over other interference species. The fluorescence intensity at 661 nm showed good linearity in the range of H 2 S concentration from 0 to 10 μM, with an excellent limit of detection (LOD) as low as 81.52 nM. Impressively, CIT-H 2 S has been visualized for detecting H 2 S in drug-induced inflammatory cell and zebrafish models, thus indicating that CIT-H 2 S is a robust tool with the ability to study the occurrence and development of hydrogen sulfide and inflammation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hydrogen sulfide (H 2 S) is a crucial endogenous gasotransmitter that plays a role in various physiological and pathological processes. Therefore, accurate and rapid monitoring of H 2 S in organisms is highly significant for understanding the underlying pathological mechanisms and facilitating early diagnosis of related diseases. In this study, we developed a novel fluorescent probe, B-CHO-NO 2 , based on a bodipy fluorophore, which exhibits excellent sensitivity and selectivity towards H 2 S. The design of the probe exploits the nucleophilicity of H 2 S by introducing a formyl group as the ortho-participating moiety, significantly enhancing the reaction rate with H 2 S. In cellular and zebrafish models, the probe B-CHO-NO 2 successfully achieved fluorescence imaging of endogenous and exogenous H 2 S. The development of probe B-CHO-NO 2 provides a powerful tool for biological studies of H 2 S and diagnosis of related diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

It has been well established that Hydrogen sulfide (H 2 S) is involved in various pathophysiological processes. Therefore, accurate monitoring H 2 S levels in vitro or vivo is of great significance in biological systems. Herein, we firstly developed a thiomaleimide-based compound MAL-1 bearing aggregation-induced emission characteristic for selective response toward H 2 S due to its nucleophilicity. The proposed sensor presented prominent sensitivity and selectivity with low detection limit of 75 nM and pseudo-first-order reaction rate constant of 9.65 × 10 -2  s -1 , as well as low cytotoxicity which works well in recognizing H 2 S in real samples and visualizing H 2 S in living cells. Thus, it could be concluded that the novel thiomaleimide-based probe would be a promising tool for assessing intracellular H 2 S levels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The olfactory system is one of the six basic sensory nervous systems. Developing artificial olfactory systems is challenging due to the complexity of chemical information decoding and memory. Conventional chemical sensors can convert chemical signals into electric signals to decode gas information but they lack memory functions. Additional storage and processing units would significantly increase the complexity and power consumption of the devices, especially for portable and wearable devices. Here, an olfactory-inspired in-sensor organic electrochemical transistor (OI-OECT) is proposed, with the integrated functions of chemical information decoding, tunable memory level, and selectivity of vapor sensing. The ion-gel electrolyte endows the OI-OECT with the function of tunable memory levels and a low operating voltage. Typical synaptic behaviors, including inhibitory postsynaptic current and paired-pulse facilitations, are successfully achieved. Importantly, the gas memory level can be effectively modulated by the gate voltages (0 and -1 V), which realized the transformation of volatile and nonvolatile memory. Furthermore, benefiting from the recognition of multiple gases and ability to detect cumulative damage caused by gases, the OI-OECT is demonstrated for early warning system targeting leakage detection of two gases (NH 3 and H 2 S). This work achieves the integrated functions of chemical gas information decode, tunable gas memory level, and selectivity of gas in a single device, which provides a promising pathway for the development of future artificial olfactory systems.

Metal oxide gas sensors (MOGS), crucial components in monitoring air quality and detecting hazardous gases, are well known for their poisoning effects when exposed to certain gas molecules, such as hydrogen sulfide. Surprisingly, our research reveals that high-temperature H 2 S treatment leads to an enhancement effect rather than response decay. This study investigates the time-decaying response enhancement, being attributed to the formation of metal sulfide and metal sulfate on the metal oxide's surface, enhancing the electronic sensitization. Such an enhancement effect is demonstrated for various gases, including CO, CH 3 CH 2 OH, CH 4 , HCHO, and NH 3 . Additionally, the impacts of H 2 S treatment on the response and recovery time are also observed. Surface compositional analysis are conducted with X-ray photoelectron spectroscopy. A proposed mechanism for the enhancement effect is elaborated, highlighting the role of electronic sensitization and the sulfide-sulfate component. This research offers valuable insights into the potential applications of metal oxide sensors in sulfide-presented harsh environments in gas sensing, encouraging future exploration of optimized sensor materials, operation temperature, and the development of hydrogen sulfide poisoning-resistant and higher sensitivity MOGS.

This work primarily reviewed the response mechanism of fluorescent probes for H 2 S detection in foodstuffs in recent years, as well as the methodologies employed for detecting foodstuffs. Firstly, the significance of studying H 2 S gas as an important signaling molecule is introduced. Subsequently, a review of the response mechanism of the scientific community on how to detect H 2 S in foodstuffs samples by fluorescent probe technology is carried out. Secondly, the methods commonly used for detecting foodstuffs samples are discussed, including the test strip method and the spiking recovery methods. Nevertheless, despite the significant advancements in this field, there remain some research gaps. Finally, the article identifies the remaining issues that require further attention in current research and proposes avenues for future investigation. More importantly, this work identifies the current limitations of research in this field and proposes future applications of fluorescent probes for H 2 S in assessing food freshness and determining food spoilage. Therefore, this review will provide robust technical support for the protection of consumer health and the advancement of the sustainable development of the food industry and also put forward some new ideas and suggestions for future research.

Alzheimer's disease (AD) represents a devastating form of neurodegeneration, hallmarked by a relentless erosion of memory and cognitive faculties. One key player in this complex pathology is hydrogen sulfide (H 2 S), a gaseous neurotransmitter that is highly concentrated in the brain. Its fluctuating levels have been compellingly linked to the onset and progression of AD. Despite the availability of numerous fluorescent probes for detecting H 2 S, targeted imaging of this neurotransmitter within AD models remains underexplored. To bridge this gap, we have engineered an innovative near-infrared (NIR) "turn-on" fluorescent probe, designated as probe 1. Crafted around a dicyanoisophorone scaffold, the probe incorporates a strategic methoxy modification to facilitate a bathochromic spectral shift. Impressively, upon binding with H 2 S, probe 1 exhibited a robust 46-fold enhancement in fluorescence at a wavelength of 680 nm. We successfully deployed this probe to visualize both exogenous and endogenous H 2 S in living cells and zebrafish. Further, our pathogenic investigations have corroborated that diminished H 2 S levels are intricately linked to an escalation in amyloid plaque formation. Most crucially, we employed probe 1 to capture real-time images of H 2 S concentrations within the hippocampal tissue of AD mouse models. This revealed a significant depletion in H 2 S levels, thereby underscoring the probe's immense potential as an effective tool for the diagnosis and prevention of Alzheimer's disease.

The equilibrium state of hydrogen sulfide (H 2 S), a gaseous signaling molecule produced by lysosomal metabolites, in vivo is crucial for cellular function. Abnormal fluctuations in H 2 S concentration can interfere with the normal function of lysosomes, which has been closely linked to the pathogenesis of a variety of diseases. In view of this, a novel fluorescent probe Lyso-DPP based on 1,3,5-triarylpyrazolines was developed for the precise detection of H 2 S in lysosomes by using the hydrophilic morpholine moiety as a lysosomal targeting unit, and 2,4-dinitroanisole as a fluorescence-quenching and H 2 S-responsive unit. The probe cleverly combines the advantages of simple synthesis, sensitive blue fluorescence turn-on with a limit of detection, LOD, of 97.3 nM, good stability, and fast response time (10 min), which makes Lyso-DPP successful in portable monitoring of meat freshness in the form of test strips. Moreover, the excellent biocompatibility and precise targeting capability of the probe Lyso-DPP make it perform well in the monitoring of H 2 S in lysosomes, living cells, and zebrafish. This work not only provides new technical tools for food quality control but also paves up new ideas for early diagnosis and treatment of H 2 S-related diseases.

Hydrogen selenide (H 2 Se) is an emerging biomolecule of interest with similar properties to that of other gaseous signaling molecules (i.e., gasotransmitters that include nitric oxide, carbon monoxide, and hydrogen sulfide). H 2 Se is enzymatically generated in humans where it serves as a key metabolic intermediate in the production of selenoproteins and other selenium-containing biomolecules. However, beyond its participation in biosynthetic pathways, its involvement in cellular signaling or other biological mechanisms remains unclear. To uncover its true biological significance, H 2 Se-specific chemical tools capable of functioning under physiological conditions are required but lacking in comparison to those that exist for other gasotransmitters. Recently, researchers have begun to fill this unmet need by developing new H 2 Se-releasing compounds, along with pioneering methods for selenide detection and quantification. In combination, the chemical tools highlighted in this review have the potential to spark groundbreaking explorations into the chemical biology of H 2 Se, which may lead to its branding as the fourth official gasotransmitter.

This study evaluates the effectiveness of self-assessed exposure (SAE) data collection for characterization of hydrogen sulfide (H2S) risks in water and wastewater management, challenging the adequacy of traditional random or campaign sampling strategies. We compared 3 datasets derived from distinct strategies: expert data with activity metadata (A), SAE without metadata (B), and SAE with logbook metadata (C). The findings reveal that standard practices of random sampling (dataset A) fail to capture the sporadic nature of H2S exposure. Instead, SAE methods enhanced by logbook metadata and supported by reliable detection and calibration infrastructure (datasets B and C) are more effective. When assessing risk, particularly peak exposure risks, it is crucial to adopt measures that capture exposure variability, such as the range and standard deviations. This finer assessment is vital where high H2S peaks occur in confined spaces. Risk assessment should incorporate indices that account for peak exposure, utilizing variability measures like range and standard or geometric standard deviation to reflect the actual risk more accurately. For large datasets, a histogram is just as useful as statistical measures. This approach has revealed that not only wastewater workers but also water distribution network workers, can face unexpectedly high H2S levels when accessing confined underground spaces. Our research underscores the need for continuous monitoring with personal electrochemical gas detector alarm systems, particularly in environments with variable and potentially hazardous exposure levels., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.)

Hydrogen sulfide (H 2 S) is a common toxic gas that threatens the quality and safety of environmental water and food. Herein, a new near-infrared fluorescent probe DTCM was synthesized and characterized by single crystal X-ray diffraction for sensing H 2 S. It exhibited a remarkable "turn-on" near-infrared (NIR) emission response at 665 nm with a remarkably massive Stokes shift of 175 nm, super-rapid detection ability (within 30 s), excellent photostability, high selectivity and sensitivity (limit of detection, LOD = 58 nM). Additionally, the probe was successfully utilized for the detection of H 2 S in environmental water samples. The DTCM-loaded test papers enabled convenient and real-time monitoring of H 2 S produced by food spoilage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The ubiquity of diverse material entities in environmental matrices renders the deployment of unifunctional fluorescent indicators inadequate. Consequently, this study introduces a ratiometric dual-emission fluorescent sensor (Probe CP), synthesized by conjugating phenothiazine coumarin to hydroxycoumarin through a piperazine linker for concurrent detection of HClO and H 2 S. Upon interaction with HClO, the phenothiazine unit's sulfur atom undergoes oxidation to sulfoxide, facilitating a shift from red to green fluorescence in a ratiometric manner. Concurrently, at the opposite terminus of Probe CP, 2,4-dinitroanisole serves as the reactive moiety for H 2 S recognition; it restores the blue emission characteristic of 7-hydroxycoumarin while maintaining the red fluorescence emanating from phenothiazine coumarin as an internal standard for ratio-based assessment. Exhibiting elevated specificity and sensitivity coupled with minimal detection thresholds (0.0506 μM for HClO and 1.7292 μM for H 2 S) alongside rapid equilibration periods (3 min for HClO and half an hour for H 2 S), this sensor was efficaciously employed in cellular environments and within zebrafish models as well as imaging applications pertaining to alcohol-induced hepatic injury in murine subjects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Municipal solid waste (MSW) landfills are a significant source of methane (CH 4 ) emissions in the United States, contributing to global warming. Current landfill gas (LFG) management methods, like the landfill cover system and LFG collection system, do not entirely prevent LFG release. Biocovers have the potential to reduce CH 4 emissions through microbial oxidation. However, LFG also contains carbon dioxide (CO 2 ) and trace hydrogen sulfide (H 2 S) depending on waste composition, temperature, moisture content, and age of waste. An innovative biogeochemical cover (BGCC) was developed to tackle these concerns. This cover comprises a biochar-based biocover layer overlaid with a basic oxygen furnace (BOF) steel slag layer. The biochar-based biocover layer oxidizes CH 4 emissions, while the BOF slag layer reduces CO 2 and H 2 S through carbonation and sulfidation reaction mechanisms. The BGCC system's field performance remains unexamined. Therefore, a large-scale tank setup simulating near-field conditions was developed to evaluate the BGCC system's ability to mitigate CH 4 , CO 2 , and H 2 S from LFG simultaneously. Synthetic LFG was passed through the BGCC in five distinct phases, each designed to simulate the varying gas compositions and flux rates typical of MSW landfill. Gas profiles along the depth were monitored during each phase, and gas removal efficiency was measured. After testing, biocover and BOF slag samples were extracted to analyze physico-chemical properties. Batch tests were also conducted on samples extracted from the biocover and BOF slag layers to determine potential CH 4 oxidation rates and residual CO 2 sequestration capacity. The results showed that the BGCC system's CH 4 removal efficiency decreased with higher CH 4 flux rates, achieving its highest removal (74.7-79.7%) at moderate influx rates (23.9-25.5 g CH 4 /m 2 -day) and reducing to its lowest removal (27.4%) at the highest influx rate (57.5 g CH 4 /m 2 -day). Complete H 2 S removal occurred during Phase 3 in the biocover layer of BGCC system. CH 4 oxidation rates were highest near the upper (277.9 µg CH 4 /g-day) and lowest in the deeper region of the biocover layer. In the tank experiment, CO 2 breakthrough occurred after 156 days due to drying of the BOF slag layer, with an average residual carbonation capacity of 46 gCO 2 /kg slag after moisture adjustment. Overall, the BGCC system effectively mitigated LFG emissions, including CH 4 , CO 2 , and H 2 S, at moderate flux rates, showing promise as a comprehensive solution for LFG management., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this work, bacterial cellulose (BC) derived from Nata de Coco is a polysaccharide material, and it is further processed into bacterial cellulose nanocrystal (BCNC) via acid hydrolysis. Then BCNC is doped with transition metals to enhance its amine/hydrogen sulfide response. Therefore, the aim of this study is to investigate the use of transition metals as indicators to detect amine and hydrogen sulfide gas for efficiently monitoring food spoilage. BCNCs were treated with various concentrations of silver nitrate (AgNO 3 ) and copper sulfate pentahydrate (CuSO 4 ·5H 2 O). Then the dropwise addition of ascorbic acid was applied to reduce Ag + and Cu 2+ to Ag 0 (silver nanoparticle) and Cu 0 (copper nanoparticle), which refer to red brown and red wine colors, respectively. The results indicated that BCNC/Ag nanoparticles were spherical, while BCNC/Cu nanoparticles exhibited a rod-like structure. XRD results also presented the incorporation of Ag and Cu nanoparticles, as confirmed by both crystallography structures. Furthermore, UV-Vis spectra showed the adsorption bands at 422-430 nm and 626-629 nm, belonging to Ag and Cu nanoparticles. After H 2 S and ammonia gas exposure, BH/Ag and BH/Cu films turned black from brown and red. In conclusion, transition metal-doped BCNCs exhibit potential for innovative food spoilage gas sensors., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)