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1.
Talanta ; 235: 122747, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517615

RESUMO

Microchip capillary electrophoresis (MCE) is a powerful technique for rapid separation; however, its acceptance in routine laboratories is still limited. Compromises caused by the efforts for solving different problems, such as reducing its cost of fabrication and ensuring high separation efficiency, undermine the competitiveness of this technology compared to other separation techniques. Contrary to the conventional pursuit of narrow microchannels, this study investigated the suitability of microchips with channels at the sub-millimeter level, targeting the simplification of the overall operation, cost reduction, and robustness improvement. To this effect, we considered the influence of pressurized flow and Joule heating on the separation. The suppression of pressurized flow with viscous solutions was confirmed through a combination of simulations and experimental results, indicating that the buffer viscosity was enough for successful separation. We fabricated channels of 200 µm × 230 µm using computer numerical controlled (CNC) machining and obtained theoretical plate numbers of 4.8 × 105 m-1 and 5.3 × 105 m-1 for fluorescein isothiocyanate (FITC) labeled small molecules and DNA fragments, respectively, with a buffer viscosity of 168 mPa s (0.5 % hydroxypropyl methylcellulose, HPMC). These values are comparable with that of narrow-bore microchips. Furthermore, we did not observe any deleterious effects with low-conductivity buffers. We investigated the rapid and highly sensitive detection of mycoplasma contamination and the real samples of circulating cell-free DNA (cfDNA), which gave a limit of detection (LOD) as low as 2.3 ng mL-1. Owing to the significant reduction in cost, ease of operation, and fast separation capabilities demonstrated in this work, MCE can be a viable alternative to the usual slab gel electrophoresis running in most biological laboratories.


Assuntos
Eletroforese em Microchip , DNA , Eletroforese Capilar , Derivados da Hipromelose , Limite de Detecção
2.
Analyst ; 146(19): 5973-5979, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34499067

RESUMO

Cell membrane permeability is one of the main indicators of cytotoxicity and related to many critical biological pathways. Here, we determined the Cd2+-induced membrane permeability of human MCF-7 cells using ferrocene methanol molecular probes based on scanning electrochemical microscopy (SECM). The cell height and topography were examined with an impermeable Ru(NH3)6Cl3 probe. The membrane permeability exhibited no significant changes when the Cd2+ incubation time was less than 2 h and its concentration was less than 40 µM. The permeability increased when the Cd2+ concentration was greater than 60 µM, or when the incubation time was longer than 3 h. From the combined 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and cytoskeleton imaging experiments, it was found that the changes occurred because the cells exhibited a defensive mode and their membranes contracted when treated with a low concentration of Cd2+ for a short time. However, the cell membranes were irreversibly damaged when the cytoskeleton structures were destroyed, and the cell activities decreased at high concentrations over long periods. Interestingly, through the comparison with an x-scan study, it was found that DPV technology shows a higher performance in the detection of changes in the membrane permeability. Using a combination of cytoskeleton fluorescence imaging and cell-viability tests, the effect of the cadmium metal on the cell membrane permeability can be explored deeper and more comprehensively. This study provides a new idea for exploring the changes in the cell membrane permeability and may be helpful for rapid evaluation of cytotoxicity.


Assuntos
Cádmio , Cádmio/toxicidade , Permeabilidade da Membrana Celular , Sobrevivência Celular , Humanos , Microscopia Eletroquímica de Varredura , Permeabilidade
3.
Int J Mol Sci ; 22(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34502213

RESUMO

Bone marrow stromal cell antigen 2 (BST-2), also known as CD317 or tetherin, has been identified as a host restriction factor that suppresses the release of enveloped viruses from host cells by physically tethering viral particles to the cell surface; however, this host defense can be subverted by multiple viruses. For example, human immunodeficiency virus (HIV)-1 encodes a specific accessory protein, viral protein U (Vpu), to counteract BST-2 by binding to it and directing its lysosomal degradation. Thus, blocking the interaction between Vpu and BST-2 will provide a promising strategy for anti-HIV therapy. Here, we report a NanoLuc Binary Technology (NanoBiT)-based high-throughput screening assay to detect inhibitors that disrupt the Vpu-BST-2 interaction. Out of more than 1000 compounds screened, four inhibitors were identified with strong activity at nontoxic concentrations. In subsequent cell-based BST-2 degradation assays, inhibitor Y-39983 HCl restored the cell-surface and total cellular level of BST-2 in the presence of Vpu. Furthermore, the Vpu-mediated enhancement of pesudotyped viral particle production was inhibited by Y-39983 HCl. Our findings indicate that our newly developed assay can be used for the discovery of potential antiviral molecules with novel mechanisms of action.


Assuntos
Fármacos Anti-HIV/farmacologia , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Ensaios de Triagem em Larga Escala/métodos , Proteínas do Vírus da Imunodeficiência Humana/antagonistas & inibidores , Domínios e Motivos de Interação entre Proteínas/efeitos dos fármacos , Proteínas Virais Reguladoras e Acessórias/antagonistas & inibidores , Antígenos CD/metabolismo , Proteínas Ligadas por GPI/antagonistas & inibidores , Proteínas Ligadas por GPI/metabolismo , Infecções por HIV/metabolismo , Infecções por HIV/virologia , Células HeLa , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , Humanos , Nanotecnologia/métodos , Proteínas Virais Reguladoras e Acessórias/metabolismo , Replicação Viral
4.
Talanta ; 234: 122626, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364435

RESUMO

Mass spectrometry (MS)-based strategies and related software tools using glycan mass lists have greatly facilitated the analysis of intact glycopeptides. Most glycan mass lists are derived from normal glycans of mammals and contain limited monosaccharides, which has significantly hindered high throughput studies of unusual glycosylation events observed in other species. In this work, an integrated strategy was developed for the construction of a species-specific glycan mass list from glycan structure databases and published papers. We developed a computational tool called LibGlycan, which could process the different formats of glycans. Then, the software tool generated a glycan library that contained the monoisotope mass, average mass, isotope distribution, and glycan mass list for input into Byonic software. This strategy was applied to analyze the N-glycosylation of rice roots and O-glycosylation of Acinetobacter baumannii ATCC17978, leading to the identification of 296 and 145 intact glycopeptides respectively. Combined, these results show that this strategy is a robust computational approach for the determination of glycan diversity within different complex biological systems.


Assuntos
Glicopeptídeos , Espectrometria de Massas em Tandem , Animais , Glicopeptídeos/metabolismo , Glicosilação , Polissacarídeos , Software
5.
Talanta ; 234: 122670, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364471

RESUMO

Binding of a target by a probe for selective detection depends on the state of the probes on the sensing interface. Here, the hanging strand length of triple-helix DNA was used to form tripod probes immobilized via π-π interactions on a reduced graphene-oxide substrate. The spacing between the probes was adjusted by controlling the lengths of the tripod "feet" on the substrate; that is, increased probe spacing occurred when foot size increased over the range of 6-12 bases. The surface coverages and electron-transfer rates mediated the tripod DNA probes were characterized by electrochemical methods and atomic force microscopy. The electron-transfer mediated by the tripod DNA probes was higher than that mediated by doubled-stranded DNA. Then different sizes tripod DNA probes were developed for protein-CEA detection. The DNA probes with 10 bases feet showed the best detection limit of detection of 10-6 ng/mL in the detection linear range (10-6 - 25 ng/mL). The result demonstrated the tripod DNA probes with different sizes could obtain excellent sensitivity when it applied to the target with appropriate size. This interspace-controlled biosensing interface of tripod DNA probes with enhanced charge transfer should find widespread applications in clinical, medical, biological, and environmental areas for precise detection of differently sized targets.


Assuntos
Técnicas Biossensoriais , Grafite , DNA , Sondas de DNA , Técnicas Eletroquímicas , Limite de Detecção
6.
Anal Chem ; 93(32): 11284-11290, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34342436

RESUMO

An effective and precise electrochemiluminescence resonance energy transfer (ECL-RET), including the efficient regulation over the proximity of a donor and an acceptor and the reliable stimuli responsive as well as the avoidance of undesirable probes leakage, etc., is significant for the development of an accurate and sensitive ECL detection method; yet, the current literature in documentation involves only a limited range of such ECL-RET systems. Herein, we propose an ECL-RET strategy with dually quenched ultralow background signals and a dual-stimuli responsive, accurate signal output for the ultrasensitive and reliable detection of anatoxin-a (ATX-a). The dual quenching is accomplished by an integrated ECL-RET probe of metal organic frameworks (MOFs) encapsulated into Ru(bpy)32+ (Ru-MOF) (donor) coated with silver nanoparticles (AgNPs) shell (acceptor 1) and close proximity with DNA-ferrocene (Fc) (acceptor 2). Multistimuli responsive DNAzyme facilitated the accurate signal switch by both target ATX-a and hydrogen peroxide (H2O2). Because of the specific recognition of the aptamer toward ATX-a, an intricate design of the DNA sequence enabled the exposure of the Ag+-dependent DNAzyme sequence and H2O2 in situ generated Ag+ triggering a catalytic cleavage reaction to freely release the two ECL-RET energy acceptors, thus switching the ECL signal significantly and achieving ultrasensitive detection. It is noteworthy that AgNPs are key in this ECL-RET strategy, serving both as the gate-keepers for avoiding ECL probes leakage and also the ECL energy acceptors, and mostly importantly serving as the redox substrate for the subsequent DNAzyme catalytic signal switch. The proposed ECL-RET aptasensor for ATX-a detection displayed splendid monitoring performance with a quite low detection limit of 0.00034 mg mL-1. This sensor not only led to the development of a dual-quenching ECL-RET system but also provided meaningful multistimuli responsive ECL biosensing platform construction, which shows a promising application prospect in complicated sample analysis.


Assuntos
DNA Catalítico , Nanopartículas Metálicas , Técnicas Eletroquímicas , Transferência de Energia , Peróxido de Hidrogênio , Medições Luminescentes , Prata , Tropanos
7.
ACS Sens ; 6(6): 2290-2298, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34042418

RESUMO

N-cadherin serves as an important oncobiomarker of epithelial-to-mesenchymal transition (EMT) progression, which identifies invasion and metastasis of malignant tumor cells. Although many efforts have been devoted to quantitative detection of N-cadherin, efforts to analyzing the protein of interest at intact cellular levels are scarce. Herein, a metal cluster-based electrochemical biosensing system is developed to determine the expressing levels of N-cadherin during the EMT process of tumor cells. To be specific, a peptide with a unique sequence and function is designed as a reductant and an anchor to synthesize metal clusters in a precise manner. Consequently, peptide-modified metal clusters possess N-cadherin-targeting, photoluminescence, and electrocatalytic properties. Especially, the redox-active metal clusters function as both an electron-transfer mediator and an electronic conductor for enhanced electrochemical sensing. These favorable features enable them as a rapid, sensitive, and reliable whole-cell biosensor, which integrates the fluorescence and electrochemical signals. This cytosensor can accurately quantify the expression levels of N-cadherin on at least 5000 tumor cells. Further, the current signals of model cancer cells gradually increase with EMT progression, indicating tumor cell-type evolution. Our study represents the advanced bioprobe and analytical methods for accurate quantitation of a biomarker to identify tumor progression.


Assuntos
Técnicas Biossensoriais , Transição Epitelial-Mesenquimal , Neoplasias , Caderinas , Humanos , Células Tumorais Cultivadas
8.
J Hazard Mater ; 417: 125986, 2021 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-33990038

RESUMO

Sensitive, convenient and rapid detection devices for toxic Cr(VI) suitable for filed use are required. Smartphone can be used as the detector, but the quality of images taken with a smartphone may depend on the ambient light and the operator. In this work, two types of low-cost and portable smartphone-based devices used for fluorescence spots brightness and size dual-mode detection of Cr(VI) were constructed with the aid of the 3D printing, which avoids the effect of ambient light and maintains a fixed position of the phone camera relative to the samples. Based on the brightness reflected by the blue channel of RGB values of the images of carbon nanodots, a linear relationship between quenching efficiency and concentration of Cr(VI) in a range of 0.2-150 µM with a limit of detection of 0.058 µM was attained, which is comparable to or better than that from fluorescence spectrometers. With the size variation of fluorescence spots, a linear range of 10-350 µM was acquired and it is more intuitive for direct naked-eye estimation of the concentration of Cr(VI). The applicability of the proposed devices for the detection of Cr(VI) was verified with water and soil samples with recoveries ranging in 95.0-108.2%.


Assuntos
Pontos Quânticos , Carbono , Cromo , Smartphone
9.
Talanta ; 230: 122320, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33934784

RESUMO

The complex natural organic matter of the Suwannee River fulvic acid (SRFA) standard was analyzed by online reversed-phase chromatography with Orbitrap MS/MS using collision-induced dissociation (CID). The number of isobars per nominal mass could be reduced to a single dominantly abundant species in a chromatographic run, sharing some ions with signals having the identical molecular formula in adjacent chromatographic segments and later serving as a precursor ion for fragmentation. A very large proportion of the same fragment ions existed in adjacent chromatographic fractions. The difference in the fragment ions in adjacent chromatographic fractions could be attributed to a gradual change in the formula composition of precursor ions in a chromatographic run. It could be concluded that dissolved organic matter (DOM) molecules with the same elemental composition in different chromatographic fractions may have very similar molecular structures. In addition, we propose a possible DOM model that might greatly deepen our understanding of the behavior of DOM in aquatic matrices.

10.
Anal Methods ; 13(14): 1672-1680, 2021 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-33861233

RESUMO

Based on the strategy of increasing the number of oxygen vacancies to improve the catalytic performance, we have developed a novel electrochemical sensor based on the multivalent metal oxides cerium dioxide and manganous oxide (Mn3O4/CeO2) for reliable determination of extracellular hydrogen peroxide (H2O2) released from living cells. The Mn3O4/CeO2 nanocomposite was characterized by high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical performance of the Mn3O4/CeO2 nanocomposite modified glassy carbon electrode (Mn3O4/CeO2/GCE) was investigated. Owing to the abundant oxygen vacancies and strong synergistic effect between the multivalent Ce and Mn, the sensor exhibited excellent catalytic activity and selectivity for the electrochemical detection of H2O2 with a low quantitation limit of 2 nM. Moreover, Mn3O4/CeO2/GCE exhibited excellent reproducibility, repeatability, and long-term storage stability. Because of these remarkable analytical advantages, the constructed sensor was able to determine H2O2 released from living cells with satisfactory results. The results showed that the Mn3O4/CeO2 sensor is a promising candidate for a nanoenzymatic H2O2 sensor with the possibility of applications in physiology and diagnosis.


Assuntos
Peróxido de Hidrogênio , Nanocompostos , Técnicas Eletroquímicas , Limite de Detecção , Oxigênio , Reprodutibilidade dos Testes
11.
Talanta ; 228: 122224, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33773729

RESUMO

Carbon nanodots (CNDs) have been widely applied in variety of fields, while some evidences indicate their components may be complicated. In this work, capillary electrophoresis (CE) was used to evaluate the effect of synthetic conditions of fluorescent CNDs prepared through the hydrothermal method using citric acid (CA) and Triaminoguanidinium chloride (TGCl) as the starting materials. The results indicated that the fluorescent components of the products were affected by the ratio of the starting materials, the reaction temperature and reaction time. Under selected conditions, a ratio of TGCl to CA of 1:6, the reaction at 180 °C for 3 h, the product contains more than 4 fluorescent components with similar optical properties. CNDs were used for the determination of Cr(VI) in environmental samples with recoveries ranging in 95.3-107%, and the mechanism was also confirmed.

12.
Nanoscale ; 13(3): 1863-1868, 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33438714

RESUMO

Three dimensional (3D) DNA walkers hold great potential in serving as an ideal candidate for signal transduction and amplification in bio-assays. However, the autonomous operation of 3D DNA walkers inside living cells is still few and far between, which could be attributed to the lack of suitable driving forces and moderate efficiency in terms of the cellular uptake of such complex 3D DNA components. Herein, a newly updated autonomously operated and highly integrated 3D DNA walker on Au nanoparticles (Au NPs)/zeolitic imidazolate framework-8 (ZIF-8) was activated in a tumor microenviroment and its signal amplified assay capability in living cells was demonstrated using miRNA as a sensing model biomolecule. Specifically, we assembled a 3D DNA motor, including Zn2+-dependent DNAzyme and substrates on the AuNPs grafted on ZIF-8. After being delivered into a living cell, ZIF-8 was efficiently degraded in the tumor microenvironment (low pH value), locally releasing the Zn2+ and DNA motor. Then, a self-sufficient DNA motor autonomously performed the bio-analytical task of imaging miRNA-10b, with a low detection limit of 34 pM. Also, such self-sufficient 3D walkers allowed real-time imaging of MDA-MB-231 cells by intracellular operation. This method demonstrates the self-sufficient 3D DNA motor's bioanalytical application in living cells which may inspire various other biological applications including gene delivery, therapy, etc.


Assuntos
Nanopartículas Metálicas , MicroRNAs , DNA , Ouro , Humanos , MicroRNAs/genética , Andadores
13.
Artigo em Inglês | MEDLINE | ID: mdl-33471365

RESUMO

A photocatalyst system is generally comprises a catalyst and cocatalyst to achieve light absorption, electron-hole separation, and surface reaction. It is a challenge to develop a single photocatalyst having all functions so as to lower the efficiency loss. Herein, the active GaN4 site is integrated into a polymeric carbon nitride (CN) photocatalyst (GCN), which displays an excellent H2 production rate of 9904 µmol h-1 g-1 . It is 162 and 3.3 times higher than that of CN with the absence (61 µmol h-1 g-1 ) and presence (2981 µmol h-1 g-1 ), respectively, of 1.0 wt % Pt. Under light irradiation the electron is injected and stored at the GaN4 site, where the LUMO locates. The HOMO distributes on the aromatic ring resulting in spatial charge separation. Transient photovoltage discloses the electron-storage capability of GCN. The negative GaN4 promotes proton adsorption in the excited state. The positive adsorption energy drives H2 desorption from GaN4 after passing the electron to the proton. This work opens up opportunities for exploring a novel catalyst for H2 production.

14.
Biosens Bioelectron ; 175: 112915, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33383431

RESUMO

Dopamine participates in many physiological and pathological processes. Dynamic monitoring of dopamine levels in the cytoplasm of a single living cell reflects not only the functional state of dopamine synthesis factors but also the processes of related neurodegenerative diseases. Due to the low content of cytoplasmic dopamine and the difficulty to keep cells alive during the operating process, the detection of cytoplasmic dopamine is still challenging. Herein, a solid-phase microextraction (SPME) technique integrated nanobiosensor was employed to trace and quantify dopamine concentration fluctuations in the cytoplasm of a single living cell. We designed a polypyrrole modified carbon fiber nanoprobe as a bifunctional nanoprobe that can extract cytoplasmic dopamine and then perform electrochemical detection. This bifunctional nanoprobe can detect 10 pmol/L extracted dopamine and detected a 60% decrease of the cytoplasmic dopamine concentration in a single living cell by K+ stimulation. This study allowed for the first time serially detecting cytoplasmic dopamine while keeping the target cell alive, which might yield a new method for research on dopamine neurotoxicity and the related drug action mechanisms for neurodegenerative disease.


Assuntos
Técnicas Biossensoriais , Doenças Neurodegenerativas , Citoplasma , Dopamina , Humanos , Polímeros , Pirróis , Microextração em Fase Sólida
15.
Nat Commun ; 11(1): 4973, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009376

RESUMO

Li-rich layered oxide cathode materials show high capacities in lithium-ion batteries owing to the contribution of the oxygen redox reaction. However, structural accommodation of this reaction usually results in O-O dimerization, leading to oxygen release and poor electrochemical performance. In this study, we propose a new structural response mechanism inhibiting O-O dimerization for the oxygen redox reaction by tuning the local symmetry around the oxygen ions. Compared with regular Li2RuO3, the structural response of the as-prepared local-symmetry-tuned Li2RuO3 to the oxygen redox reaction involves the telescopic O-Ru-O configuration rather than O-O dimerization, which inhibits oxygen release, enabling significantly enhanced cycling stability and negligible voltage decay. This discovery of the new structural response mechanism for the oxygen redox reaction will provide a new scope for the strategy of enhancing the anionic redox stability, paving unexplored pathways toward further development of high capacity Li-rich layered oxides.

16.
Sci Adv ; 6(29): eabb1421, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32832637

RESUMO

Metalloenzymes are promising anticancer candidates to overcome chemoresistance by involving unique mechanisms. To date, it is still a great challenge to obtain synthetic metalloenzymes with persistent catalytic performance for cancer-specific DNA cleavage and operando imaging. Here, an artificial metalloenzyme, copper cluster firmly anchored in bovine serum albumin conjugated with tumor-targeting peptide, is exquisitely constructed. It is capable of persistently transforming hydrogen peroxide in tumor microenvironment to hydroxyl radical and oxygen in a catalytic manner. The stable catalysis recycling stems from the electron transfer between copper cluster and substrate with well-matched energy levels. Notably, their high biocompatibility, tumor-specific recognition, and persistent catalytic performance ensure the substantial anticancer efficacy by triggering DNA damage. Meanwhile, by coupling with enzyme-like reactions, the operando therapy effect is expediently traced by chemiluminescence signal with high sensitivity and sustainability. It provides new insights into synthesizing biocompatible metalloenzymes on demand to visually monitor and efficiently combat specific cancers.

17.
Talanta ; 218: 121096, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32797866

RESUMO

We propose a hydraulically assisted eddy-current etching method for the controllable fabrication of pico/femtoliter sampling probes with equal inner diameters along the length of the probe. The relative standard deviations of the outer and inner diameters (O.D. and I.D., respectively) of several 1.07-µm-I.D. sampling probe tips fabricated in a single batch using this method were 2.2% and 2.8%, respectively, and the average O.D./I.D. ratio of these probes was 1.17. The probe fabrication method has high reproducibility, and sharp tips are produced, which is advantageous for the transfer of ultra-small sample volumes. Further, the narrow, equal diameter, cylindrical inner bore allows the online, visual determination of the pipetted sample volume by utilizing a microscopic imaging system to measure the liquid length. This value is converted linearly to the pipetted volume, whose measurement error is on a sub-pixel level. Image-based sampling using the fabricated probes was achieved by connecting the probe to an electroosmotic pump, which allowed the controlled pipetting of pico/femtoliter samples. Because the pipette allows samples of the same volume to be measured accurately, the pipette was applied for the semiquantitative mass spectrometry analysis of the metabolites in individual epidermal cells sampled from different parts of Portulaca oleracea plants. The results show that different types of cells have distinct metabolite profiles. Further, the experiments showed that, in dopamine-rich leaves, the content of dopamine in the petioles is higher than that in the foliage. The probe fabrication strategy opens new avenues for the controllable pipetting of ultra-small volume samples and the realization of the visual pipetting of pico/femtoliter samples.

18.
J Chem Phys ; 152(24): 244703, 2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32610958

RESUMO

Mixed phase TiO2 (Degussa P25) exhibits superior photocatalytic performance and stability due to the formation of the hetero-phase junction between anatase and rutile. However, the large bandgap limits its visible light activity. CdS is a photocatalyst with a broad light absorption band up to 550 nm. Constructing a hetero-phase junction will greatly promote the photocatalytic activity of CdS. In this work, the one-step solvothermal method was used to synthesize CdS hetero-phase junction with both hexagonal wurtzite (WZ) and cubic zinc blende (ZB) phases. The ratio of WZ and ZB phases can be tuned by adjusting the solvent ratio and reaction time to construct type I junction and effectively separate the photogenerated electron-hole pair. Under visible-light illumination, the optimal photocatalytic activity of the prepared material reaches 7.96 mmol h-1 g-1, and the quantum efficiency is 36.7% at 420 nm, which is three times higher than that of any single-phase sample (cubic or hexagonal phase) and maintains high photocatalytic stability as well. It is expected that this work will provide a feasible prospect for the practical application of high-efficiency homogeneous junction photocatalysts.

19.
Nanoscale ; 12(23): 12647-12654, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32515460

RESUMO

Microfluidic synthesis has attracted extensive attention due to the ability for the multistep precise control of the synthesis parameters, continuous and reproducible preparation, and its ease of integration. However, its commercial application is still affected by its low production efficiency. In this case, we report a high-throughput continuous flow synthesis of highly dispersed PtFeCu/C nanocatalysts using a metal microchip setup with four parallel channels. The high flow rate and integrated channels enabled improving the throughput, whereby 1.33 g h-1 of catalysts could be achieved with the flow rate of 1200 mL h-1 under the experimental conditions. The as-prepared PtFeCu/C exhibited excellent performance, 1.94 times higher than Pt/C for methanol oxidation. More importantly, the yield of the PtFeCu/C nanocatalysts could be further increased through designing numerous parallel channels, which might provide a promising approach for large-scale commercialization of the catalysts. Such a high-throughput fabrication pathway is significant for the large-scale industrial production of nanomaterials.

20.
Anal Chem ; 92(14): 9613-9619, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32458676

RESUMO

Aggregation-induced electrochemiluminescence (AIECL) of the dichlorobis(1,10-phenanthroline)ruthenium(II) (Ru(phen)2Cl2)/tri-n-propylamine (TPrA) system was systematically investigated in H2O-MeCN media. Up to a 120-fold increase in the ECL intensity was observed when the H2O fraction (v%) was changed from 30% to 70%, whereas only an approximately 5.7-fold increase in the corresponding aggregation-induced fluorescence emission was demonstrated. The gradual formation of clusters of Ru(phen)2Cl2 nanoaggregates along with the increase in the H2O fraction to MeCN, which was verified by dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), was believed to be responsible for the remarkable ECL enhancement. Significantly, the above-mentioned AIECL behavior was found to be very sensitive to the types and sequences of nucleic acids present in solution, which provided an effective and novel strategy for distinguishing RNA from DNA and for differentiating different miRNAs. The present study could have a substantial impact in various research areas, such as molecular sensors, bioimaging probes, organelle-specific imaging, and tumor diagnosis.


Assuntos
Acetonitrilas , Técnicas Eletroquímicas/métodos , Medições Luminescentes/métodos , Ácidos Nucleicos/química , Propilaminas/química , Compostos de Rutênio/química , Água
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