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Mesoporous Fe3O4-loaded silver nanocomposites (Fe3O4@Ag) were simply fabricated as bi-functional nanozymes for the catalysis-based detection and removal of Hg2+ ions. It was found that the as-prepared magnetic Fe3O4@Ag could display peroxidase-like catalysis activity that could be rationally enhanced in the presence of Hg2+ ions. To our surprise, the shell of the Ag element may decrease the catalysis of the Fe3O4 to some degree. However, the Ag particles could serve as the probes for specifically recognizing Hg2+ ions and trigger increased catalysis through the formation of Ag-Hg alloys, with a decreased signal background. A high-throughput colorimetric analytical method was thereby developed based on the Fe3O4@Ag catalysis for probing Hg2+ ions in the muscles of fish by using 96-well plates, at linear Hg2+ concentrations ranging from 0.010 to 2.5 mg kg-1. Moreover, the developed colorimetric analytical method was applied to evaluate Hg2+ levels in muscle samples of different kinds of fish. Unexpectedly, an obvious difference of Hg2+ levels in muscles of four kinds of fish was discovered, with the order of snakehead (Ophicephalus argus) > largemouth bass (Micropterus salmoides) > crucian carp (Carassius auratus) > silver carp (Hypophthalmichthys molitrix), where the carnivorous fish showed higher Hg2+ levels than the omnivorous or plant-based ones. Moreover, the as-fabricated Fe3O4@Ag adsorbents with their large specific surface area and high environmental robustness could exhibit efficient Hg2+ adsorption with capacities of up to 397.60 mg g-1. A removal efficiency of 99.40% can also be expected for Hg2+ ions from wastewater, with the magnet-aided recycling of Fe3O4@Ag adsorbents. Such an Fe3O4@Ag-based colorimetric analysis and removal strategy for Hg2+ ions should find wide applications in the fields of aquatic food safety, environmental monitoring, and clinical diagnostics of Hg-poisoning diseases.
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Carpas , Mercúrio , Nanocompostos , Animais , Mercúrio/análise , Colorimetria/métodos , ÍonsRESUMO
AIMS: Esketamine upregulates Zn2+-dependent matrix metalloproteinase 9 (MMP9) and increases the neuronal apoptosis in retinal ganglion cell layer during the early development. We aimed to test whether albumin can alleviate esketamine-induced apoptosis through downregulating Zn2+-dependent MMP9. METHODS: We investigate the role of Zn2+ in esketamine-induced neuronal apoptosis by immunofluorescence. MMP9 protein expression and enzyme activity were investigated by zymography in situ., western blot and immunofluorescence. Whole-mount retinas from P7 Sprague-Dawley rats were used. RESULTS: We demonstrated that esketamine exposure increased Zn2+ in the retinal GCL during the early development. Zn2+-dependent MMP9 expression and enzyme activity up-regulated, which eventually aggravated apoptosis. Albumin effectively down-regulated MMP9 expression and activity via binding of free zinc, ultimately protected neurons from apoptosis. Meanwhile albumin treatment promoted activated microglia into multi-nucleated macrophagocytes and decreased the inflammation. CONCLUSION: Albumin alleviates esketamine-induced neuronal apoptosis through decreasing Zn2+ accumulation in GCL and downregulating Zn2+-dependent MMP9.
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Metaloproteinase 9 da Matriz , Retina , Ratos , Animais , Metaloproteinase 9 da Matriz/metabolismo , Regulação para Baixo , Ratos Sprague-Dawley , Retina/metabolismo , Apoptose , Albuminas/metabolismo , Albuminas/farmacologia , Zinco/farmacologiaRESUMO
Classical swine fever virus (CSFV) is a single-stranded RNA flavivirus that can cause serious diseases in porcine species, including symptoms of infarction, systemic hemorrhage, high fever, or depression. Viperin is an important interferon-inducible antiviral gene that has been shown to inhibit CSFV, but the exact mechanisms by which it is able to do so remain poorly characterized. In the present study, we determined that CSFV infection led to viperin upregulation in PK-15 cells (porcine kidney cell). When viperin was overexpressed in these cells, this markedly attenuated CSFV replication, with clear reductions in viral copy number after 12 to 48 hours postinfection. Immunofluorescence microscopy revealed that the viral NS5A protein colocalized with viperin in infected cells, and this was confirmed via confocal laser scanning microscopy using labeled versions of these proteins, and by co-immunoprecipitation which confirmed that NS5A directly interacts with viperin. When NS5A was overexpressed, this inhibited the replication of CSFV, and we determined that the radical SAM domain and N-terminal domain of viperin was critical for its ability to bind to NS5A, with the latter being most important for this interaction. Together, our in vitro results highlight a potential mechanism whereby viperin is able to inhibit CSFV replication. These results have the potential to assist future efforts to prevent or treat systemic CSFV-induced disease, and may also offer more general insights into the antiviral role of viperin in innate immunity.
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Vírus da Febre Suína Clássica/fisiologia , Peste Suína Clássica/imunologia , Proteínas/imunologia , Proteínas não Estruturais Virais/metabolismo , Replicação Viral , Animais , Células Cultivadas , Peste Suína Clássica/genética , Vírus da Febre Suína Clássica/genética , Regulação da Expressão Gênica , Células HEK293 , Humanos , Imunoprecipitação , Interferons/fisiologia , Domínios e Motivos de Interação entre Proteínas , Proteínas/genética , Transdução de Sinais , Suínos , Proteínas não Estruturais Virais/genéticaRESUMO
Correction for 'A capillary-based fluorimetric platform for the evaluation of glucose in blood using gold nanoclusters and glucose oxidase in the ZIF-8 matrix' by Luping Feng et al., Analyst, 2020, 145, 5273-5279, DOI: 10.1039/D0AN01090A.
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A capillary-based fluorimetric analysis method was developed for probing glucose (Glu) in blood using Glu oxidase-anchored gold nanoclusters (GOD-AuNCs) and the ZIF-8 matrix. AuNCs were attached with GOD to be further encapsulated into the ZIF-8 matrix through the protein-mediated formation route. The resulting GOD-AuNCs@ZIF-8 nanocomposites could present the AuNC-improved catalysis of GOD and ZIF-8-improved environmental stability. The ZIF-8-enhanced fluorescence intensity of AuNCs could also be expected. Moreover, a capillary-based fluorometric platform was constructed for sensing Glu by coating the capillaries first with GOD-AuNCs and then the ZIF-8 matrix. Herein, Glu was introduced through the self-driven sampling to trigger the GOD-catalyzed production of hydrogen peroxide, which could induce the fluorescence quenching rationally depending on the Glu concentrations. The developed fluorimetric method could allow for the rapid and simple detection of Glu with the concentrations linearly ranging from 5.0 µM to 2.5 mM. Besides, the feasibility of practical applications was demonstrated by the evaluation of Glu in blood showing the recoveries of 96.2%-103.4%. Importantly, the proposed design of the capillary-based fluorimetric platform by the synergetic combination of catalysis-specific recognition and fluorescence signaling may open a new door toward extensive applications in the biological sensing, catalysis, and imaging fields.
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Glucose Oxidase , Nanopartículas Metálicas , Capilares , Glucose , Ouro , VeiasRESUMO
OBJECTIVES: Hydrogen sulfide (H2S) is involved in regulating cell apoptosis and proliferation. However, The effects and mechanism of H2S on the apoptosis of mammary epithelial cells that suffer from an inflammatory response remain unknown. RESULTS: An inflammatory cell model was used to explore whether exogenous H2S regulates lipopolysaccharides (LPS)-induced cell proliferation and apoptosis. We found that H2S affected cell viability, the inflammatory response and apoptosis in LPS-treated cells in a concentration-dependent manner. Moreover, exogenous H2S rescued LPS-induced cystathionine γ-lyase (CSE) inhibition and cystathionine ß-synthase (CBS) synthesis. Interestingly, in cells undergoing inflammation-induced apoptosis, H2S activated the PI3K/Akt and NFκB signal pathways both tested concentrations. Akt appeared to be a key crosstalk molecule that played a "bridge" role. CONCLUSIONS: H2S regulates LPS-induced inflammation and apoptosis by activating the PI3K/Akt/NFκB signaling pathway. Hence, NaHS may be clinically useful for preventing or treating mastitis.
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Apoptose/efeitos dos fármacos , Células Epiteliais/metabolismo , Sulfeto de Hidrogênio/farmacologia , Glândulas Mamárias Animais/metabolismo , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Bovinos , Linhagem Celular , Células Epiteliais/patologia , Feminino , Inflamação/metabolismo , Inflamação/patologia , Glândulas Mamárias Animais/patologiaRESUMO
Polyhydric poly (vinyl alcohol) was covalently loaded with a 1-pyrenecarboxyaldehyde fluorophore. The yielded PVA-Pyr composites can serve as powerful adsorbents and strong fluorescent probes for the highly efficient adsorption and sensitive fluorimetric detection with test strips of curcumin in samples of urine and plant extracts.
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Curcumina/análise , Corantes Fluorescentes , Extratos Vegetais/análise , Pirenos , Urina/química , Adsorção , Humanos , Polímeros , Álcool de Polivinil , Urinálise/métodosRESUMO
Mesoporous silver-melamine (Ag-MA) nanocomposites were synthesized simply by the controlled supermolecular self-assembly process to be modified onto the electrodes for the electroanalysis of multiple sulfides in blood or wastewater. It was discovered that Ag-MA nanocomposites could be prepared with various morphological structures depending on the Ag-to-MA ratios. Furthermore, the electrodes modified with mesoporous Ag-MA nanowires could display stable and sharp electrochemical peaks of solid-state AgCl at a considerably low potential approaching zero, thus circumventing any interference from possibly coexisting electroactive substances in the background. More importantly, the yielded AgCl signals would decrease selectively induced by sulfides through the specific sulfide-chloride replacement reactions toward the transferring of AgCl into non-electroactive Ag2S. The developed electroanalysis strategy could facilitate the selective detection of multiple sulfides (i.e., S2- or H2S, Sx2-, cysteine, and S2O32-) in the complicated media with high-level salts such as blood and wastewater, showing a linear concentration range from 0.50 to 512 µM as exemplified for S2- ions in blood. Such an electroanalysis device equipped with the portable electrochemical transducer can be tailored for the field-deployable monitoring of a variety of sulfides in clinical and environmental analysis fields.
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Microplastics (MPs) as the formidable pollutants with high toxicity and difficult degradation may threaten the aquaculture industry and human health, making it highly necessary to develop the effective removal methods. In this article, Fe3O4 nanoparticles (NPs) were initially fabricated with mesoporous structure, but showing undesirable adsorption efficiencies for the adsorption of MPs (lower than 70%). Inspired by the reefs-rebuilding corals acting as the sinks for various marine pollutants like plastic, Fe3O4 NPs were coated further with adhesive polymerized dopamine (PDA) yielding Fe3O4@PDA absorbents. Unexpectedly, it was discovered that the corals-mimicking absorbents so formed could allow for the removal of MPs with dramatically enhanced efficiencies up to 98.5%, which is over about 30% higher than those of bare Fe3O4 NPs. Herein, the PDA shells might conduct the increased adhesion to MPs, presumably through the formation of hydrogen bonding, π-π stacking, and hydrophobic interactions. A fast (within 20 min) and stable adsorption of MPs can also be expected, in addition to the PDA-improved environmental storage of Fe3O4 NPs. Subsequently, the Fe3O4@PDA adsorbents were utilized to remove MPs from different water sources with high efficiencies, including pure water, suburban streams, village rivers, lake water, inner-city moats, and aquaculture water. Such a magnet-recyclable adsorbent may provide a new way for rapid, effective, and low-cost removal of MPs pollutants from various water systems.
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Tubular Co9S8/CdS heterostructures have been successfully synthesized by in-situ growing CdS onto Co9S8 nanotubes through a simultaneous immobilization and in-situ reduction strategy. It turned out that the so-obtained heterostructure with Co9S8/CdS molar ratio of 1/10 can display a broad light absorption edge and especially much enhanced capacity for photocatalytic reduction of Cr(VI) under visible light. The characterization analysis and experimental results suggested that an interfacial electrostatic field between Co9S8 and CdS elements in the heterostructure could be constructed due to their different Fermi levels, allowing for more quantities of highly reductive electrons to participate in the photocatalytic reaction. Therefore, the so-obtained Co9S8/CdS (1/10) heterostructures could achieve the photocatalytic reduction efficiency of 100% within 20 min, which was more than two and four times larger than that of pristine CdS and Co9S8, respectively. Moreover, the possible photocatalytic reaction mechanism for reducing Cr(VI) was investigated and found to follow the direct Z-scheme charge transfer pathway. This novel fabrication route for composite photocatalysts with tubular heterostructures could lead to the widespread implementations for the elimination of various harmful pollutants in the process of environmental governance.
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Ammonia (NH3) is an irritating and harmful gas that affects cell apoptosis and autophagy. Sirtuin 5 (SIRT5) has multiple enzymatic activities and regulates NH3-induced autophagy in tumor cells. In order to determine whether SIRT5 regulates NH3-induced bovine mammary epithelial cell apoptosis and autophagy, cells with SIRT5 overexpression or knockdown were generated and in addition, bovine mammary epithelial cells were treated with SIRT5 inhibitors. The results showed that SIRT5 overexpression reduced the content of NH3 and glutamate in cells by inhibiting glutaminase activity in glutamine metabolism, and reduced the ratio of ADP/ATP. The results in the SIRT5 knockdown and inhibitor groups were comparable, including increased content of NH3 and glutamate in cells by activating glutaminase activity, and an elevated ratio of ADP/ATP. It was further confirmed that SIRT5 inhibited the apoptosis and autophagy of bovine mammary epithelial cells through reverse transcription-quantitative PCR, western blot, flow cytometry with Annexin V FITC/PI staining and transmission electron microscopy. In addition, it was also found that the addition of LY294002 or Rapamycin inhibited the PI3K/Akt or mTOR kinase signal, decreasing the apoptosis and autophagy activities of bovine mammary epithelial cells induced by SIRT5-inhibited NH3. In summary, the PI3K/Akt/mTOR signal involved in NH3-induced cell autophagy and apoptosis relies on the regulation of SIRT5. This study provides a new theory for the use of NH3 to regulate bovine mammary epithelial cell apoptosis and autophagy, and provides guidance for improving the health and production performance of dairy cows.
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A nanozyme with 2D/1D heterostructure has been fabricated by the in-situ growth of molybdenum disulfide nanosheets (MoS2 NSs) onto single-walled carbon nanotubes (SWCNTs). It was discovered that the so-obtained SWCNTs@MoS2 nanozyme could exhibit greatly improved peroxidase-like catalysis, due to that the formed 2D/1D interfacial coupling in the heterostructure might provide more active sites and exhibit enhanced charge transferring during the catalytic reactions, as confirmed by the X-ray photoelectron spectroscopy, photoluminescence, electrochemical impedance spectra and radical capturing experiments. Furthermore, the catalysis of the developed nanozyme could be selectively inhibited by glutathione (GSH) through the competitive consumption of hydroxyl radicals with enzyme substrate in the catalytic reaction system. A SWCNTs@MoS2 catalysis-based colorimetric strategy was further proposed for the quantitative analysis of GSH with the concentrations linearly ranging from 0.01 to 1000.0 µM. Besides, the feasibility of the developed colorimetric method was evaluated by monitoring GSH separately in the extractions from hela cells and human serum, promising the extensive applications for monitoring various biological species like GSH in the clinical laboratory. Importantly, such a fabrication route for nanozyme with 2D/1D heterostructure may pave the way towards the wide applications for designing various nanzymes with improved catalysis.
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Molibdênio , Nanotubos de Carbono , Catálise , Colorimetria/métodos , Glutationa/análise , Células HeLa , Humanos , Molibdênio/químicaRESUMO
Tubular In2O3 was fabricated by the annealing of In-MIL-68 and further treated by Ar plasma to yield oxygen vacancies (Ov) followed by the growth of In2S3 nanoflowers. Unexpectedly, the resulting porous In2S3@In2O3 composites were discovered to display a broad visible-light response and especially enhanced capacities for efficient photocatalytic production of H2O2 in pure water, with a rate of 4.59 µmol·g-1·min-1. An apparent quantum yield of 28.9% at 420 nm can also be expected without the use of noble metals or organic scavengers. Herein, the high light utilization might be profited from their porous tubular heterostructure for powerful "light captivity". Moreover, the Ar plasma-derived Ov sites on the composites might tune the H2O2 generation route from the single-electron reduction to the two-electron one toward the significantly enhanced photocatalysis, as validated by the Koutecky-Levich plots. This work demonstrates a new perspective of designing porous heterostructures with the advantages of high light harvest and plasma-derived Ov active sites. Importantly, it may provide a promising defect-induced strategy of two-electron reduction triggered by the plasma treatment for the efficient photocatalytic H2O2 production under visible light.
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A selective photoelectrochemical (PEC) sensor has been designed for the signal-on detection of H2S using g-C3N4 nanosheets that were treated with N2 plasma for depositing Cd probes. It was discovered that the yielded Cd/N@g-C3N4 nanocomposites could present enhanced photocurrents of specific responses to H2S under visible light irradiation, in contrast to the ones without the pretreatment of N2 plasma showing no H2S response. Herein, the Cd probes deposited on g-C3N4 nanosheets might react with H2S to generate CdS on Cd/N@g-C3N4, forming the efficient heterojunctions. Especially, the plasma-derived N contents might act as the "bridge" to promote charge transfer between the generated CdS and g-C3N4, resulting in the "signal-on" PEC responses to H2S. A selective PEC sensor was thereby developed for sensing H2S of concentrations linearly ranging from 40.0 to 10,000 pM, with a detection limit of about 21 pM. Also, the feasibility of sensing H2S in industrial waste gas was demonstrated by recovery tests. More importantly, this N2 plasma treatment route for g-C3N4 nanosheets may open a new door toward the construction of a Cd probe-based heterojunction for the signal-on PEC sensing platform, which is promising for the wide application in the fields of environmental monitoring, food safety, and biomedical analysis.
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Ammonia is a harmful gas with a pungent odor, participates in the regulation of a variety of apoptosis and autophagy, which in turn affects the growth and differentiation of cells. To test the regulation of NH3 on the apoptosis and autophagy of mammary epithelial cells, we selected NH4Cl as NH3 donor in vitro model. MTT and CCK-8 assay kits were employed to detect cell activity. Real-time quantitative PCR and western blot methods were used to detect the abundance of inflammatory molecules, apoptosis markers, and autophagy genes. We selected TUNEL kit and the Annexin-FITC/PI method to detect apoptosis. TEM analysis was used to detect autophagic vesicles, and MDC stain evaluated the formation of autophagosome. The results indicated that NH4Cl reduced cell viability in a concentration-dependent manner and promoted cell inflammatory response, apoptosis, and autophagy. NH4Cl stimulation notable increased the autophagosomes number. Interestingly, we also detected that the addition of LY294002 and Rapamycin inhibited the PI3K/Akt pathway and the mTOR pathway, respectively, resulting in changes in both apoptosis and autophagy. Therefore, we draw a conclusion that NH3 may regulate the apoptosis and autophagic response of bovine mammary epithelial cells through the PI3K/Akt/mTOR signaling pathway. Further investigations on ammonia's function in other physiological respects, will be critical to provide theoretical help for the improvement of production performance. It will be also helpful for controlling the harmful gas ammonia concentration in the livestock house to protect the health of dairy cows.
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Células Epiteliais Alveolares/efeitos dos fármacos , Cloreto de Amônio/farmacologia , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Transdução de Sinais/efeitos dos fármacos , Animais , Bovinos , Linhagem Celular , Sobrevivência Celular , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismoRESUMO
A highly selective and sensitive photoelectrochemical (PEC) detection method has been developed for the analysis of copper (Cu2+) ions using nanoflower-like ZnO@CdS heterojunctions, of which ZnO was first in situ grown onto the indium tin oxide electrodes by a hydrothermal method and then coated with CdS through the chemical bath deposition route. It was discovered that the ZnO@CdS heterojunction so formed could serve as a photosensitive catalyst with improved charge separation for visible-light-driven PEC responses. Enhanced visible-light harvesting of nanocomposites could also be expected with CdS as the visible-light sensitizer. Furthermore, the introduction of Cu2+ ions could cause a rational decrease in the photocurrents of nanocomposites through the specific interaction between CdS and Cu2+ ions. A ZnO@CdS heterojunction-based PEC sensor was thereby developed for the detection of Cu2+ ions in blood in the linear concentrations ranging from 0.50 to 80 nM, with a limit of detection of 0.18 nM. Such a heterojunction-based PEC detection platform constructed using two photocatalytic materials with matched band structures are promising for a wide range of applications for sensing Cu2+ ions in clinical diagnostics, food monitoring, and environmental analysis.
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Compostos de Cádmio/química , Cobre/sangue , Nanocompostos/química , Sulfetos/química , Compostos de Estanho/química , Óxido de Zinco/química , Técnicas Biossensoriais , Técnicas Eletroquímicas , Eletrodos , Humanos , Íons/sangue , Processos FotoquímicosRESUMO
BACKGROUND: Drug repositioning refers to discovering new indications for the existing drugs, which can improve the efficiency of drug research and development. METHODS: In this work, a novel drug repositioning approach based on integrative multiple similarity measure, called DR_IMSM, is proposed. The process of integrative similarity measure contains three steps. First, a heterogeneous network can be constructed based on known drug-disease association, shared entities information for drug pairwise and diseases pairwise. Second, a deep learning method, DeepWalk, is used to capture the topology similarity for drug and disease. Third, a similarity integration and adjusting process is further conducted to obtain more comprehensive drug and disease similarity measure, respectively. RESULTS: On this basis, a Bi-random walk algorithm is implemented in the constructed heterogeneous network to rank diseases for each drug. Compared with other approaches, the proposed DR_IMSM can achieve superior performance in terms of AUC on the gold standard datasets. Case studies further confirm the practical significance of DR_IMSM.
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Reposicionamento de Medicamentos/métodos , Algoritmos , Biologia Computacional/métodos , Aprendizado Profundo , Humanos , Modelos LogísticosRESUMO
Heteroatom doping is one of the effective ways to improve the catalytic performances of nanozymes. In the present work, the plasma-assisted controllable doping of nitrogen (N) into MoS2 nanosheets has been initially proposed, resulting in efficient nanozymes. The so-obtained nanozymes were characterized separately by TEM, XRD, XPS, and FTIR. It was discovered that the resulting N-doped MoS2 nanosheets could present dramatically enhanced peroxidase-like catalytic activities depending on the plasma treatment time. Particularly, that with the 2-min treatment could display the highest catalytic activity, which is over 3-fold higher than that of pristine MoS2, that was also demonstrated by the kinetics studies. Herein, the N2 plasma treatment could facilitate the N elements to be doped covalently into MoS2 nanosheets to achieve the increased surface wettability and affinity of nanozymes for the improved access of the electrons and substrates of catalytic reactions. More importantly, the covalent doping of N elements into MoS2 nanosheets with a lower Fermi level, as evidenced by the DFT analysis, could facilitate the promoted electron transferring, resulting in the enhanced catalysis of N-doped MoS2 nanozymes, in addition to the high catalytic stability in water. Such a controllable plasma treatment strategy may open a new door toward the large-scale applications for doping heteroatoms into various nanozymes with improved catalysis performances.
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Dissulfetos/química , Molibdênio/química , Nanoestruturas/química , Nitrogênio/química , Gases em Plasma/química , Catálise , Teoria da Densidade Funcional , Peróxido de Hidrogênio/química , Cinética , Oxirredução , Peroxidases/química , Peroxidases/metabolismo , Propriedades de SuperfícieRESUMO
A visible-light-driven photoelectrochemical (PEC) sensor has been developed for the "signal-on" analysis of Hg2+ by the synergetic combination of low-bandgap Ag2S and wide-bandgap ZnS quantum dots (QDs). Ag2S QDs were synthesized with bead-chain-like structure by the self-assembly route and further covalently bound with ZnS QDs to be coated onto the indium tin oxide (ITO) electrodes. It was discovered that the ZnS@Ag2S-modified electrodes could display the visible-light-driven PEC behavior, of which Ag2S and ZnS QDs could act as the PEC sensitizer and Hg2+-recognition probe, respectively. More importantly, the photocurrent responses of the developed electrodes could be specifically turned on in the presence of Hg2+ under the visible-light irradiation, presumably due to that Hg2+ might conduct a Zn-to-Hg exchange on ZnS QDs to trigger the formation of HgS/ZnS@Ag2S heterojunction towards the enhanced electron-hole separation. The as-prepared PEC sensor could facilitate the detection of Hg2+ with concentrations ranging from 0.010-1000 nM, with a detection limit of about 1.0 pM. Besides, the feasibility of practical applications of the developed PEC analysis strategy was verified by probing Hg2+ in environmental water samples. Such a visible-light-driven PEC detection platform with the unique "turn-on" signal output may promise for the extensive applications for Hg2+ evaluation.
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Mesoporous silver-melamine (Ag-MA) nanocomposites were synthesized by controlled supramolecular self-assembly with various structural morphologies. It was discovered that the rod-like Ag-MA nanocomposites could present the larger Hg2+-enhanced catalysis by forming Ag-Hg alloys. Also, they could display large surface-to-volume area and high aqueous stability for the selective Hg2+ enrichment and absorption of Hg2+ ions by yielding the stable coordination complexes. A catalysis-based colorimetric method was thus developed using 96-wells plates to probe Hg2+ ions in blood and wastewater with the linear Hg2+ concentrations ranging from 1.0 nM to 600 nM and 0.50 nM to 700 nM, respectively. Besides, mesoporous Ag-MA absorbents could facilitate the removal of Hg2+ ions in wastewater with the removal efficiency up to 99.76 % and the absorption capacity of 598.99 mg g-1.