Hydrogen Sulfide Promotes Postnatal Cardiomyocyte Proliferation by Upregulating SIRT1 Signaling Pathway.

Hydrogen sulfide (H2S) has been identified as a novel gasotransmitter and a substantial antioxidant that can activate various cellular targets to regulate physiological and pathological processes in mammals. However, under physiological conditions, it remains unclear whether it is involved in regulating cardiomyocyte (CM) proliferation during postnatal development in mice. This study mainly aimed to evaluate the role of H2S in postnatal CM proliferation and its regulating molecular mechanisms. We found that sodium hydrosulfide (NaHS, the most widely used H2S donor, 50-200 µM) increased neonatal mouse primary CM proliferation in a dose-dependent manner in vitro. Consistently, exogenous administration of H2S also promoted CM proliferation and increased the total number of CMs at postnatal 7 and 14 days in vivo. Moreover, we observed that the protein expression of SIRT1 was significantly upregulated after NaHS treatment. Inhibition of SIRT1 with EX-527 or si-SIRT1 decreased CM proliferation, while enhancement of the activation of SIRT1 with SRT1720 promoted CM proliferation. Meanwhile, pharmacological and genetic blocking of SIRT1 repressed the effect of NaHS on CM proliferation. Taken together, these results reveal that H2S plays a promotional role in proliferation of CMs in vivo and in vitro and SIRT1 is required for H2S-mediated CM proliferation, which indicates that H2S may be a potential modulator for heart development in postnatal time window.

Copper-based grape pest management has impacted wine aroma.

Despite the high energetic cost of the reduction of sulfate to H2S, required for the synthesis of sulfur-containing amino acids, some wine Saccharomyces cerevisiae strains have been reported to produce excessive amounts of H2S during alcoholic fermentation, which is detrimental to wine quality. Surprisingly, in the presence of sulfite, used as a preservative, wine strains produce more H2S than wild (oak) or wine velum (flor) isolates during fermentation. Since copper resistance caused by the amplification of the sulfur rich protein Cup1p is a specific adaptation trait of wine strains, we analyzed the link between copper resistance mechanism, sulfur metabolism and H2S production. We show that a higher content of copper in the must increases the production of H2S, and that SO2 increases the resistance to copper. Using a set of 51 strains we observed a positive and then negative relation between the number of copies of CUP1 and H2S production during fermentation. This complex pattern could be mimicked using a multicopy plasmid carrying CUP1, confirming the relation between copper resistance and H2S production. The massive use of copper for vine sanitary management has led to the selection of resistant strains at the cost of a metabolic tradeoff: the overproduction of H2S, resulting in a decrease in wine quality.

Recent advances in the application of gasotransmitters in spinal cord injury.

Spinal Cord Injury (SCI) is a condition characterized by complete or incomplete motor and sensory impairment, as well as dysfunction of the autonomic nervous system, caused by factors such as trauma, tumors, or inflammation. Current treatment methods primarily include traditional approaches like spinal canal decompression and internal fixation surgery, steroid pulse therapy, as well as newer techniques such as stem cell transplantation and brain-spinal cord interfaces. However, the above methods have limited efficacy in promoting axonal and neuronal regeneration. The challenge in medical research today lies in promoting spinal cord neuron regeneration and regulating the disrupted microenvironment of the spinal cord. Studies have shown that gas molecular therapy is increasingly used in medical research, with gasotransmitters such as hydrogen sulfide, nitric oxide, carbon monoxide, oxygen, and hydrogen exhibiting neuroprotective effects in central nervous system diseases. The gas molecular protect against neuronal death and reshape the microenvironment of spinal cord injuries by regulating oxidative, inflammatory and apoptotic processes. At present, gas therapy mainly relies on inhalation for systemic administration, which cannot effectively enrich and release gas in the spinal cord injury area, making it difficult to achieve the expected effects. With the rapid development of nanotechnology, the use of nanocarriers to achieve targeted enrichment and precise control release of gas at Sites of injury has become one of the emerging research directions in SCI. It has shown promising therapeutic effects in preclinical studies and is expected to bring new hope and opportunities for the treatment of SCI. In this review, we will briefly outline the therapeutic effects and research progress of gasotransmitters and nanogas in the treatment of SCI.

Therapeutic Potential of Hydrogen Sulfide in Reproductive System Disorders.

Hydrogen sulfide (H2S), previously regarded as a toxic exhaust and atmospheric pollutant, has emerged as the third gaseous signaling molecule following nitric oxide (NO) and carbon monoxide (CO). Recent research has revealed significant biological effects of H2S in a variety of systems, such as the nervous, cardiovascular, and digestive systems. Additionally, H2S has been found to impact reproductive system function and may have therapeutic implications for reproductive disorders. This paper explores the relationship between H2S and male reproductive disorders, specifically erectile dysfunction, prostate cancer, male infertility, and testicular damage. Additionally, it examines the impact of H2S regulation on the pathophysiology of the female reproductive system, including improvements in preterm birth, endometriosis, pre-eclampsia, fetal growth restriction, unexplained recurrent spontaneous abortion, placental oxidative damage, embryo implantation, recovery of myometrium post-delivery, and ovulation. The study delves into the regulatory functions of H2S within the reproductive systems of both genders, including its impact on the NO/cGMP pathway, the activation of K+ channels, and the relaxation mechanism of the spongy smooth muscle through the ROCK pathway, aiming to broaden the scope of potential therapeutic strategies for treating reproductive system disorders in clinical settings.

Supplementation of sperm cryopreservation media with H2S donors enhances sperm quality, reduces oxidative stress, and improves in vitro fertilization outcomes.

Cryopreservation of sperm can cause oxidative stress and damage, leading to decreased different functional parameters and fertilization potential. In this study, we evaluated two types of H2S donors: NaHS, a fast-releasing donor, and GYY4137, a slow-releasing donor during cryopreservation of goat sperm. Initially, we determined that 1.5 and 3 µM NaHS, and 15 and 30 µM GYY4137 are optimal concentrations that improved different sperm functional parameters including motility, viability, membrane integrity, lipid peroxidation, and ROS production during incubation at 38.5 °C for 90 min. We subsequently evaluated the impact of the optimal concentration of NaHS and GYY4137 supplementation on various functional parameters following thawing during cryopreservation. Our data revealed that supplementation of extender improved different parameters including post-thaw sperm motility, viability, membrane integrity, and reduced DNA damage compared to the frozen-thawed control group. The supplementation also restored the redox state, decreased lipid peroxidation, and improved mitochondrial membrane potential in the thawed sperm. Finally, we found that supplementation of the extender with NaHS and GYY4137 enhanced IVF outcomes in terms of blastocyst rate and quality of blastocysts. Our results suggest that both donors can be applied for cryopreservation as antioxidants to improve sperm quality and IVF outcomes of frozen-thawed goat sperm.

Microbial Detoxification of Sediments Underpins Persistence of Zostera marina Meadows.

Eelgrass meadows have attracted much attention not only for their ability to maintain marine ecosystems as feeding grounds for marine organisms but also for their potential to store atmospheric and dissolved CO2 as blue carbon. This study comprehensively evaluated the bacterial and chemical data obtained from eelgrass sediments of different scales along the Japanese coast to investigate the effect on the acclimatization of eelgrass. Regardless of the eelgrass habitat, approximately 1% Anaerolineales, Babeliales, Cytophagales, and Phycisphaerales was present in the bottom sediment. Sulfate-reducing bacteria (SRB) were present at 3.69% in eelgrass sediment compared to 1.70% in bare sediment. Sulfur-oxidizing bacteria (SOB) were present at 2.81% and 1.10% in the eelgrass and bare sediment, respectively. Bacterial composition analysis and linear discriminant analysis revealed that SOB detoxified H2S in the eelgrass meadows and that the larger-scale eelgrass meadows had a higher diversity of SOB. Our result indicated that there were regional differences in the system that detoxifies H2S in eelgrass meadows, either microbial oxidation mediated by SOB or O2 permeation via the physical diffusion of benthos. However, since bacterial flora and phylogenetic analyses cannot show bias and/or causality due to PCR, future kinetic studies on microbial metabolism are expected.

Assessing the efficiency and microbial diversity of H2S-removing biotrickling filters at various pH conditions.

This study aimed to investigate the operation of three parallel biotrickling filters (BTFs) in removing H2S at different pH conditions (haloalkaliphilic, neutrophilic, and acidophilic) and their associated microbial population in the biodesulfurization process. BTF columns were inoculated with enriched inoculum and experiments were performed by gradually reducing Empty Bed Retention Time (EBRT) and increasing inlet concentration in which the maximum removal efficiency and maximum elimination capacity in EBRT 60 s reached their maximum level in haloalkaline condition (91% and 179.5 g S-H2S m-3 h-1). For visualizing the attached microbial biofilms on pall rings, Scanning Electron Microscopy (SEM) was used and microbial community structure analysis by NGS showed that the most abundant phyla in haBTF, nBTF, and aBTF belong to Gammaproteobacteria, Betaproteobacteria, and Acidithiobacillia, respectively. Shannon and Simpson indexes evaluation showed a lower diversity of bacteria in the aBTF reactor than that of nBTF and haBTF and beta analysis indicated a different composition of bacteria in haBTF compared to the other two filters. These results indicated that the proper performance of BTF under haloalkaliphilic conditions is the most effective way for H2S removal from air pollutants of different industries.

Comparison of Techniques for the Quantitation of Reductive Aroma Compounds in White Wine: Links to Sensory Analysis and Cu Fractions.

Multiple analytical methodologies allow quantitation of H2S and methanethiol (MeSH) in wine, but confirmation that the determined concentrations are related to perceived off-aromas, or "reductive" faults, is yet to be provided. Fifty white wines underwent sensory evaluation and measurement of free and salt-treated H2S and MeSH concentrations by gas chromatography with sulfur chemiluminescence detection and/or gas detection tubes. The determined concentrations were compared across techniques and different analysis laboratories. Sulfhydryl off-odors in the wines were best described by boiled and rotten egg and natural gas/sewerage/durian aroma attributes. The wines with the highest ratings for both aromas had high concentrations of free H2S, free MeSH, and/or salt-treated MeSH but were unrelated to salt-treated H2S. The free sulfhydryl concentrations and their associated aromas appeared to be suppressed by specific Cu fractions in the wines. This study provides evidence of the relevant measures of reductive aroma compounds and their relation to off-odors and Cu fractions.

Acid-Triggered Degradation of Three-In-One Ag2S Quantum Dots for In Situ Ratiometric NIR-II Fluorescence Imaging-Guided Ion/Gas Combination Therapy.

Smart theranostic nanoprobes with the integration of multiple therapeutic modalities are preferred for precise diagnosis and efficient therapy of tumors. However, it remains a big challenge to arrange the imaging and two or more kinds of therapeutic agents without weakening the intended performances. In addition, most existing fluorescence (FL) imaging agents suffer from low spatiotemporal resolution due to the short emission wavelength (<900 nm). Here, novel three-in-one Ag2S quantum dot (QD)-based smart theranostic nanoprobes were proposed for in situ ratiometric NIR-II FL imaging-guided ion/gas combination therapy of tumors. Under the acidic tumor microenvironment, three-in-one Ag2S QDs underwent destructive degradation, generating toxic Ag+ and H2S. Meanwhile, their FL emission at 1270 nm was weakened. Upon introduction of a downconversion nanoparticle (DCNP) as the delivery carrier and NIR-II FL reference signal unit, the formed Ag2S QD-based theranostic nanoprobes could achieve precise diagnosis of tumors through ratiometric NIR-II FL signals. Also, the generated Ag+ and H2S enabled specific ion/gas combination therapy toward tumors. By combining the imaging and therapeutic functions, three-in-one Ag2S QDs may open a simple yet reliable avenue to design theranostic nanoprobes.

A critical review on characterization, human health risk assessment and mitigation of malodorous gaseous emission during the composting process.

Composting has emerged as a suitable method to convert or transform organic waste including manure, green waste, and food waste into valuable products with several advantages, such as high efficiency, cost feasibility, and being environmentally friendly. However, volatile organic compounds (VOCs), mainly malodorous gases, are the major concern and challenges to overcome in facilitating composting. Ammonia (NH3) and volatile sulfur compounds (VSCs), including hydrogen sulfide (H2S), and methyl mercaptan (CH4S), primarily contributed to the malodorous gases emission during the entire composting process due to their low olfactory threshold. These compounds are mainly emitted at the thermophilic phase, accounting for over 70% of total gas emissions during the whole process, whereas methane (CH4) and nitrous oxide (N2O) are commonly detected during the mesophilic and cooling phases. Therefore, the human health risk assessment of malodorous gases using various indexes such as ECi (maximum exposure concentration for an individual volatile compound EC), HR (non-carcinogenic risk), and CR (carcinogenic risk) has been evaluated and discussed. Also, several strategies such as maintaining optimal operating conditions, and adding bulking agents and additives (e.g., biochar and zeolite) to reduce malodorous emissions have been pointed out and highlighted. Biochar has specific adsorption properties such as high surface area and high porosity and contains various functional groups that can adsorb up to 60%-70% of malodorous gases emitted from composting. Notably, biofiltration emerged as a resilient and cost-effective technique, achieving up to 90% reduction in malodorous gases at the end-of-pipe. This study offers a comprehensive insight into the characterization of malodorous emissions during composting. Additionally, it emphasizes the need to address these issues on a larger scale and provides a promising outlook for future research.

Hydrogel-based radio frequency H2S sensor for in situ periodontitis monitoring and antibacterial treatment.

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 (H2S) 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 H2S sensing. Here, we report a wearable hydrogel-based radio frequency (RF) sensor capable of in situ H2S 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 H2S measurement, the wireless H2S 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.

Hydrogen Sulfide-Induced Activatable Photodynamic Therapy Adjunct to Disruption of Subcellular Glycolysis in Cancer Cells by a Fluorescence-SERS Bimodal Iridium Metal-Organic Hybrid.

The practical application of photodynamic therapy (PDT) demands targeted and activatable photosensitizers to mitigate off-target phototoxicity common in "always on" photosensitizers during light exposure. Herein, a cyclometalated iridium complex-based activatable photodynamic molecular hybrid, Cy-Ir-7-nitrobenzofurazan (NBD), is demonstrated as a biomedicine for molecular precision. This design integrates a hydrogen sulfide (H2S)-responsive NBD unit with a hydroxy-appended iridium complex, Cy-Ir-OH. In normal physiological conditions, the electron-rich Ir metal center exerts electron transfer to the NBD unit, quenches the excited state dynamics, and establishes a PDT-off state. Upon exposure to H2S, Cy-Ir-NBD activates into the potent photosensitizer Cy-Ir-OH through nucleophilic substitution. This mechanism ensures exceptional specificity, enabling targeted phototherapy in H2S-rich cancer cells. Additionally, we observed that Cy-Ir-NBD-induced H2S depletion disrupts S-sulfhydration of the glyceraldehyde-3-phosphate dehydrogenase enzyme, impairing glycolysis and ATP production in the cellular milieu. This sequential therapeutic process of Cy-Ir-NBD is governed by the positively charged central iridium ion that ensures mitochondria-mediated apoptosis in cancer cells. Dual-modality SERS and fluorescence imaging validate apoptotic events, highlighting Cy-Ir-NBD as an advanced theranostic molecular entity for activatable PDT. Finally, as a proof of concept, clinical assessment is evaluated with the blood samples of breast cancer patients and healthy volunteers, based on their H2S overexpression capability through SERS and fluorescence, revealing Cy-Ir-NBD to be a promising predictor for PDT activation in advanced cancer phototherapy.

A dual-color ESIPT-based probe for simultaneous detection of hydrogen sulfide and hydrazine.

Hydrogen sulfide (H2S) and hydrazine (N2H4) are toxic compounds in environmental and living systems, and hydrogen sulfide is also an important signaling molecule. However, in the absence of dual-color probes capable of detecting both H2S and N2H4, the ability to monitor the crosstalk of these substances is restricted. Herein, we developed an ESIPT-based dual-response fluorescent probe (BDM-DNP) for H2S and N2H4 detection via dually responsive sites. The BDM-DNP possessed absorbing strength in the detection of H2S and N2H4, with a large Stokes shift (156 nm for H2S and 108 nm for N2H4), high selectivity and sensitivity, and good biocompatibility. Furthermore, BDM-DNP can be utilized for the detection of hydrogen sulfide and hydrazine in actual soil, and gaseous H2S and N2H4 in environmental systems. Notably, BDM-DNP can detect H2S and N2H4 in living cells for disease diagnosis and treatment evaluation.

Evolutionary Rate Shifts in Coding and Regulatory Regions Underpin Repeated Adaptation to Sulfidic Streams in Poeciliid Fishes.

Adaptation to extreme environments often involves the evolution of dramatic physiological changes. To better understand how organisms evolve these complex phenotypic changes, the repeatability and predictability of evolution, and possible constraints on adapting to an extreme environment, it is important to understand how adaptive variation has evolved. Poeciliid fishes represent a particularly fruitful study system for investigations of adaptation to extreme environments due to their repeated colonization of toxic hydrogen sulfide-rich springs across multiple species within the clade. Previous investigations have highlighted changes in the physiology and gene expression in specific species that are thought to facilitate adaptation to hydrogen sulfide-rich springs. However, the presence of adaptive nucleotide variation in coding and regulatory regions and the degree to which convergent evolution has shaped the genomic regions underpinning sulfide tolerance across taxa are unknown. By sampling across seven independent lineages in which nonsulfidic lineages have colonized and adapted to sulfide springs, we reveal signatures of shared evolutionary rate shifts across the genome. We found evidence of genes, promoters, and putative enhancer regions associated with both increased and decreased convergent evolutionary rate shifts in hydrogen sulfide-adapted lineages. Our analysis highlights convergent evolutionary rate shifts in sulfidic lineages associated with the modulation of endogenous hydrogen sulfide production and hydrogen sulfide detoxification. We also found that regions with shifted evolutionary rates in sulfide spring fishes more often exhibited convergent shifts in either the coding region or the regulatory sequence of a given gene, rather than both.

Impact of hydrogen sulfide on anammox and nitrate/nitrite-dependent anaerobic methane oxidation coupled technologies.

The coupling between anammox and nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) has been considered a sustainable technology for nitrogen removal from sidestream wastewater and can be implemented in both membrane biofilm reactor (MBfR) and granular bioreactor. However, the potential influence of the accompanying hydrogen sulfide (H2S) in the anaerobic digestion (AD)-related methane-containing mixture on anammox/n-DAMO remains unknown. To fill this gap, this work first constructed a model incorporating the C/N/S-related bioprocesses and evaluated/calibrated/validated the model using experimental data. The model was then used to explore the impact of H2S on the MBfR and granular bioreactor designed to perform anammox/n-DAMO at practical levels (i.e., 0∼5% (v/v) and 0∼40 g/S m3, respectively). The simulation results indicated that H2S in inflow gas did not significantly affect the total nitrogen (TN) removal of the MBfR under all operational conditions studied in this work, thus lifting the concern about applying AD-produced biogas to power up anammox/n-DAMO in the MBfR. However, the presence of H2S in the influent would either compromise the treatment performance of the granular bioreactor at a relatively high influent NH4+-N/NO2--N ratio (e.g., >1.0) or lead to increased energy demand associated with TN removal at a relatively low influent NH4+-N/NO2--N ratio (e.g., <0.7). Such a negative effect of the influent H2S could not be attenuated by regulating the hydraulic residence time and should therefore be avoided when applying the granular bioreactor to perform anammox/n-DAMO in practice.

H2S is involved in drought-mediated stomatal closure through PLDα1 in Arabidopsis.

MAIN CONCLUSION: PLDα1 promoted H2S production by positively regulating the expression of LCD. Stomatal closure promoted by PLDα1 required the accumulation of H2S under drought stress. Phospholipase Dα1 (PLDα1) acting as one of the signal enzymes can respond to drought stress. It is well known that hydrogen sulfide (H2S) plays an important role in plant responding to biotic or abiotic stress. In this study, the functions and relationship between PLDα1 and H2S in drought stress resistance in Arabidopsis were explored. Our results indicated that drought stress promotes PLDα1 and H2S production by inducing the expression of PLDα1 and LCD genes. PLDα1 and LCD enhanced plant tolerance to drought by regulating membrane lipid peroxidation, proline accumulation, H2O2 content and stomatal closure. Under drought stress, the H2O2 content of PLDα1-deficient mutant (pldα1), L-cysteine desulfhydrase (LCD)-deficient mutant (lcd) was higher than that of ecotype (WT), the stomatal aperture of pldα1 and lcd was larger than that of WT. The transcriptional and translational levels of LCD were lower in pldα1 than that in WT. Exogenous application of the H2S donor NaHS or GYY reduced the stomatal aperture of WT, pldα1, PLDα1-CO, and PLDα1-OE lines, while exogenous application of the H2S scavenger hypotaurine (HT) increased the stomatal aperture. qRT-PCR analysis of stomatal movement-related genes showed that the expression of CAX1, ABCG5, SCAB1, and SLAC1 genes in pldα1 and lcd were down-regulated, while ACA1 and OST1 gene expression was significantly up-regulated. Thus, PLDα1 and LCD are required for stomatal closure to improve drought stress tolerance.

An Aggregation-Induced Fluorescence Probe for Detection H2S and Its Application in Cell Imaging.

Monitoring hydrogen sulfide (H2S) in living organisms is very important because H2S acts as a regulator in many physiological and pathological processes. Upregulation of endogenous H2S concentration has been shown to be closely related to the occurrence and development of tumors, atherosclerosis, neurodegenerative diseases and diabetes. Herin, a novel fluorescent probe HND with aggregation-induced emission was designed. Impressively, HND exhibited a high selectivity, fast response (1 min) and low detection limit (0.61 µM) for H2S in PBS buffer (10 mM, pH = 7.42). Moreover, the reaction mechanism between HND and H2S was conducted by Job's plot, HR-MS, and DFT. In particular, HND was successfully employed to detect H2S in HeLa cells.

Isolation, identification, and tolerance analysis of yeast during the natural fermentation process of Sidamo coffee beans.

Yeast, which plays a pivotal role in the brewing, food, and medical industries, exhibits a close relationship with human beings. In this study, we isolated and purified 60 yeast strains from the natural fermentation broth of Sidamo coffee beans to screen for indigenous beneficial yeasts. Among them, 25 strains were obtained through morphological characterization on nutritional agar medium from Wallerstein Laboratory (WL), with molecular biology identifying Saccharomyces cerevisiae strain YBB-47 and the remaining 24 yeast strains identified as Pichia kudriavzevii. We investigated the fermentation performance, alcohol tolerance, SO2 tolerance, pH tolerance, sugar tolerance, temperature tolerance, ester production capacity, ethanol production capacity, H2S production capacity, and other brewing characteristics of YBB-33 and YBB-47. The results demonstrated that both strains could tolerate up to 3% alcohol by volume at a high sucrose mass concentration (400 g/L) under elevated temperature conditions (40 ℃), while also exhibiting a remarkable ability to withstand an SO2 mass concentration of 300 g/L at pH 3.2. Moreover, S. cerevisiae YBB-47 displayed a rapid gas production rate and strong ethanol productivity. whereas P. kudriavzevii YBB-33 exhibited excellent alcohol tolerance. Furthermore, this systematic classification and characterization of coffee bean yeast strains from the Sidamo region can potentially uncover additional yeasts that offer high-quality resources for industrial-scale coffee bean production.

An injectable hydrogel dressing for controlled release of hydrogen sulfide pleiotropically mediates the wound microenvironment.

The healing of scalded wounds faces many challenges such as chronic inflammation, oxidative stress, wound infection, and difficulties in vascular and nerve regeneration. Treating a single problem cannot effectively coordinate the complex regenerative microenvironment of scalded wounds, limiting the healing and functional recovery of the skin. Therefore, there is a need to develop a multi-effect treatment plan that can adaptively address the issues at each stage of wound healing. In this study, we propose a scheme for on-demand release of hydrogen sulfide (H2S) based on the concentration of reactive oxygen species (ROS) in the wound microenvironment. This is achieved by encapsulating peroxythiocarbamate (PTCM) in the ROS-responsive polymer poly(ethylene glycol)-poly(L-methionine) (PMet) to form nanoparticles, which are loaded into a thermosensitive injectable hydrogel, F127-poly(L-aspartic acid-N-hydroxysuccinimide) (F127-P(Asp-NHS)), to create a scald dressing. The H2S released by the hydrogel dressing on demand regulates the wound microenvironment by alleviating infection, reducing oxidative stress, and remodeling inflammation, thereby accelerating the healing of full-thickness scalded wounds. This hydrogel dressing for the adaptive release of H2S has great potential in addressing complex scalded wounds associated with infection and chronic inflammation.

Dental restorative materials and halitosis: a preliminaryin-vitrostudy.

Despite the widespread use of dental restorative materials, little information exists in the literature regarding their potential impact on bad breath. This in vitro study aims to fill this gap by investigating the influence of different restorative materials on the release of hydrogen sulfide (H2S). Thirteen diverse dental restorative materials, including composites, flowable composites, glass ionomer restorative materials, high-copper amalgam, and CAD-CAM blocks, were examined. Cellulose Sponge models were used as negative and positive control. All samples were prepared with a diameter of 5 mm and a height of 2 mm. Except for the negative control group, all samples were embedded into Allium cepa L., and the emitted H2S was measured using the Wintact W8802 hydrogen sulfide monitor. Surface roughness's effect on emission was explored by roughening the surfaces of CAD-CAM material samples, and gas emission was measured again. The data were statistically analyzed using the Kruskal-Wallis test and DSCF pairwise comparison tests. Fiber-reinforced flowable composite (EverX Flow), amalgam (Nova 70-caps), and certain composite materials (IPS Empress Direct, Tetric Evoceram, Admira Fusion X-tra) released higher H2S concentrations compared to the negative control. The H2S release period lasted longer in the same materials mentioned above, along with G-aenial Universal Injectable. Indirectly used materials, such as GC Cerasmart, Vita Enamic, and Vita YZ HT, demonstrated significantly lower emissions compared to other direct restoratives. Importantly, the surface roughness of indirect materials did not significantly affect peak H2S concentrations or release times. The study reveals variations in H2S release among restorative materials, suggesting potential advantages of indirect restorative materials in reducing H2S-induced halitosis. This comprehensive understanding of the relationship between restorative materials and halitosis can empower both dental professionals and patients to make well-informed treatment choices. Notably, there is evidence supporting the enhanced performance of indirect restorative materials for individuals affected by halitosis.