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1.
Molecules ; 29(9)2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38731466

RESUMO

Tripropyl phosphate (TnPP) is a commonly used organic phosphate flame retardant in the textiles, plastics, and coating industries. Residues are commonly detected in samples from the environment and food. The availability of certified reference materials (CRMs) is essential to ensure the accuracy and traceability of detection results. In this study, a comprehensive characterization of a CRM for TnPP was carried out, and its purity was evaluated using two distinct methodologies: mass balance (MB) and quantitative nuclear magnetic resonance spectroscopy (qNMR). In the MB method, the levels of structurally related organic impurities are 1.37 mg/g. The water content was determined to be 3.16 mg/g, while inorganic impurities were found to be 0.87 mg/g, and no residual organic solvents were detected. Benzoic acid and monocrotophos were chosen as internal standards for 1H-qNMR and 31P-qNMR, respectively. The purity of the TnPP CRM was assessed as 994.6 mg/g, 994.1 mg/g, and 993.5 mg/g using MB, 1H-qNMR, and 31P-qNMR techniques, respectively. The verified purity of the TnPP CRM was ultimately determined to be 994.1 mg/g, with an expanded uncertainty of 3.4 mg/g (k = 2), ensuring traceability to the International System of Units (SI). This CRM can be effectively utilized for preparing calibration solutions suitable for the routine monitoring of TnPP residues in plastics and food samples.

2.
Electrophoresis ; 43(16-17): 1710-1723, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35617708

RESUMO

We developed a novel, convenient and low-cost one-pot strategy for preparing a zeolitic imidazolate framework-8 (ZIF-8)-silica hybrid monolithic column by adding ZIF-8 directly to a polymer solution of the silica matrix. The simulated stationary phase and monolithic column prepared under optimal conditions were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis nitrogen physisorption and zeta potential. The results obtained confirmed the successful introduction of ZIF-8 into the silica monolithic column, and the prepared monolithic column exhibited good permeability and physicochemical stability. A capillary electrochromatography method was developed based on a ZIF-8-silica hybrid monolithic column through which 15 mixed amino acids, 4 neutral compounds, 4 nipagin esters and 2 chlorinated fungicides were separated in 14, 5, 7 and 6 min, respectively, under optimal conditions. The relative standard deviations retention times and column efficiencies in run-to-run, day-to-day and column-to-column varied in the ranges of 1.90%-2.21%, 2.13%-2.51% and 3.08%-6.65%, respectively, which demonstrated that ZIF-8-silica hybrid monolithic column exhibited satisfactory reproducibility and stability. The incorporation of ZIF-8 into a silica monolithic column is a promising method for preparing novel monolithic columns composed of a metal-organic framework.


Assuntos
Eletrocromatografia Capilar , Zeolitas , Aminoácidos , Eletrocromatografia Capilar/métodos , Imidazóis/química , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Dióxido de Silício/química , Esqueleto
3.
Electrophoresis ; 43(11): 1161-1173, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35312084

RESUMO

A novel chiral stationary phase (CSP) of Zr-based metal-organic framework, l-Cys-PCN-224, was prepared by one-pot method and applied for the enantioseparation by capillary electrochromatography. The CSP was characterized by X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier-transform infrared spectra, nitrogen adsorption/desorption, circular dichroism spectrum, zeta-potential, and so on. The results revealed that the CSP had good crystallinity, high specific surface area (2580 m2 /g), and good thermal stability. Meanwhile, the cross-section of l-Cys-PCN-224-bonded open-tubular (OT) column was observed by a scanning electron microscope, which proved the successful bonding of l-Cys-PCN-224 particles to the inner wall. Relative standard deviations of the column efficiencies were 3.87%-9.14%, and not obviously changed after 200 runs, which indicated that l-Cys-PCN-224-bonded OT column had the better stability and reproducibility. Excellent chiral separation performance was verified with nine kinds of natural amino acids including acidic, neutral, and basic as the analytes. All amino acids studied achieved good separation with the resolution of 1.38-13.9 and selector factor of 1.11-3.71. These results demonstrated that the CSP had an excellent potential in the chiral separation field.


Assuntos
Eletrocromatografia Capilar , Estruturas Metalorgânicas , Aminoácidos , Eletrocromatografia Capilar/métodos , Estruturas Metalorgânicas/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo
4.
Chirality ; 34(3): 537-549, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34997664

RESUMO

Covalent organic frameworks (COFs) have been recognized as promising solid phases in capillary electrochromatography (CEC). Imine-based COF-coated open-tubular CEC column (COF TpBD-coated OT column) was prepared and characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectra, thermogravimetric analysis (TGA), nitrogen adsorption/desorption (Brunauer-Emmett-Teller [BET]), and scanning electron microscopy (SEM). The results showed that the column efficiency was up to 26,776 plate/m, and the thickness of stationary phase was about 6.00 µm for the column prepared under the optimal conditions. Enantioseparation of 15 kinds of the single chiral compounds (histidine, arginine, lysine, leucine, threonine, methionine, valine, aspartic acid and glutamic acid, fipronil, diclofop, imazamox, quizalofop-p, imazethapyr, and acephate) and 3 kinds of mixed amino acids racemaces (valine, methionine, and glutamic acid) were performed with three methods: capillary electrochromatography with COF TpBD-coated OT column (Method 1), CEC with COF TpBD-coated OT column as the separation channels, and capillary electrophoresis (CE) with HP-ß-CD as the chiral mobile phase additive (Method 2) and CE with HP-ß-CD as the chiral mobile phase additive (Method 3). Separation efficiency and chiral selectivity of Method 2 was best among the three methods. Under the optimal separation conditions of Method 2, all the enantiomers reached the baseline separation regardless of the single chiral compounds or the mixed amino acids. Relative standard deviation (RSDs) of the mean column efficiency for reproducibility and stability was in the range of 0.46-1.49%. This combination of CEC and CE has great potential for use in chiral separation.


Assuntos
Eletrocromatografia Capilar , Ciclodextrinas , Estruturas Metalorgânicas , Eletrocromatografia Capilar/métodos , Estruturas Metalorgânicas/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo
5.
Sensors (Basel) ; 21(21)2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34770661

RESUMO

Luminescent Ln-MOFs (Eu0.075Tb0.925-MOF) were successfully synthesised through the solvothermal reaction of Tb(NO3)3·6H2O, Eu(NO3)3·6H2O, and the ligand pyromellitic acid. The product was characterised by X-ray diffraction (XRD), TG analysis, EM, X-ray photoelectron spectroscopy (XPS), and luminescence properties, and results show that the synthesised material Eu0.075Tb0.925-MOF has a selective ratio-based fluorescence response to Fe3+ or Cr2O72-. On the basis of the internal filtering effect, the fluorescence detection experiment shows that as the concentration of Fe3+ or Cr2O72- increases, the intensity of the characteristic emission peak at 544 nm of Tb3+ decreases, and the intensity of the characteristic emission peak at 653 nm of Eu3+ increases in Eu0.075Tb0.925-MOF. The fluorescence intensity ratio (I653/I544) has a good linear relationship with the target concentration. The detection linear range for Fe3+ or Cr2O72- is 10-100 µM/L, and the detection limits are 2.71 × 10-7 and 8.72 × 10-7 M, respectively. Compared with the sensor material with a single fluorescence emission, the synthesised material has a higher anti-interference ability. The synthesised Eu0.075Tb0.925-MOF can be used as a highly selective and recyclable sensing material for Fe3+ or Cr2O72-. This material should be an excellent candidate for multifunctional sensors.


Assuntos
Estruturas Metalorgânicas , Corantes Fluorescentes , Ligantes , Luminescência , Difração de Raios X
6.
Biochem Biophys Res Commun ; 525(3): 581-588, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32115147

RESUMO

Long non-coding RNAs (lncRNAs) have obtained growing attention due to their potential effects as novel regulators in various tumors. This study aimed to investigate the expression and roles of lncRNA LINC01139 (LINC01139) in the progression of hepatocellular carcinoma (HCC). We found that LINC01139 was over-expressed in HCC specimens and cell lines, and its upregulation was observed to be associated with advanced TNM stage, lymph node metastasis and poor clinical prognosis of HCC patients. Multivariate analyses confirmed that LINC01139 expression was an independent poor prognostic factor for HCC patients. Functionally, the knockdown of LINC01139 suppressed cell proliferation, clone formation and metastasis of HCC cells. Moreover, luciferase assays and rescue experiments revealed that LINC01139/miR-30/MYBL2 established the ceRNA network involved in the modulation of cell proliferation and metastasis of HCC cells. Overall, LINC01139 may exhibit an oncogenic function in HCC via acting as a sponge for miR-30 to upregulate MYBL2, and may serve as a potential therapeutic target and a prognostic biomarker for HCC patients.


Assuntos
Carcinoma Hepatocelular/genética , Proteínas de Ciclo Celular/genética , Progressão da Doença , Neoplasias Hepáticas/genética , MicroRNAs/metabolismo , RNA Longo não Codificante/metabolismo , Transativadores/genética , Regulação para Cima/genética , Sequência de Bases , Ligação Competitiva , Carcinoma Hepatocelular/patologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Hepáticas/patologia , MicroRNAs/genética , Invasividade Neoplásica , Metástase Neoplásica , Prognóstico , RNA Longo não Codificante/genética , Transativadores/metabolismo
7.
Med Sci Monit ; 21: 1131-7, 2015 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-25893318

RESUMO

BACKGROUND: Whether prasugrel can take the place of clopidogrel for patients with acute coronary syndrome (ACS) is not clear. The aim of this study was to perform a meta-analysis for systematically reviewing the evidence on prasugrel in comparison to clopidogrel in patients with ACS. MATERIAL/METHODS: Relevant prospective and retrospective studies were searched in databases. Six studies were finally included. Pooled risk ratios (RRs) and 95% confidence intervals (CIs) were calculated to assess all causes of death, myocardial infarction (MI), stroke, major bleeding, major/minor bleeding, and stent thrombosis (for PCI performed). RESULTS: Compared with clopidogrel, prasugrel had similar risks of all cause of death (Pooled RR: 0.83; 95% CI: 0.64-1.06, p=0.14, I2=55%), MI (Pooled RR: 0.86; 95% CI: 0.71-1.04, p=0.12) and stroke (pooled RR: 0.88; 95% CI: 0.70-1.10, p=0.25). However, prasugrel was associated with significantly higher risk of both major bleeding (Pooled RR: 1.19; 95% CI: 0.99-1.44, p=0.06, I2=0%) and the risk of total major and minor bleeding (Pooled RR: 1.30; 95% CI: 1.15-1.48, p<0.0001, I2=0%). For the patients who underwent percutaneous coronary intervention (PCI), prasugrel was associated with significantly lower risk of stent thrombosis (Pooled RR: 0.47; 95% CI: 0.34-0.61, p<0.00001, I2=0%). CONCLUSIONS: Prasugrel has similar effects as clopidogrel in terms of all causes of death, MI, and stroke in ACS patients. For the patients who underwent PCI, prasugrel contributes to lower risk of stent thrombosis. However, prasugrel is associated with significantly higher risk of bleeding. For the patients with active pathological bleeding or a history of stroke and/or TIA, prasugrel should not be recommended.


Assuntos
Síndrome Coronariana Aguda/tratamento farmacológico , Cloridrato de Prasugrel/uso terapêutico , Antagonistas do Receptor Purinérgico P2Y/uso terapêutico , Ticlopidina/análogos & derivados , Síndrome Coronariana Aguda/complicações , Síndrome Coronariana Aguda/mortalidade , Administração Oral , Clopidogrel , Medicina Baseada em Evidências , Hemorragia/etiologia , Humanos , Infarto do Miocárdio/etiologia , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/uso terapêutico , Cloridrato de Prasugrel/administração & dosagem , Cloridrato de Prasugrel/efeitos adversos , Estudos Prospectivos , Antagonistas do Receptor Purinérgico P2Y/administração & dosagem , Antagonistas do Receptor Purinérgico P2Y/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Acidente Vascular Cerebral/etiologia , Trombose/etiologia , Ticlopidina/efeitos adversos , Ticlopidina/uso terapêutico
8.
Food Chem ; 452: 139537, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-38728891

RESUMO

The chlortetracycline (CTC) residue in food poses a threat to human health. Therefore, developing sensitive, convenient and selective analytical methods for CTC detection is crucial. This study innovatively uses tin disulfide/bimetallic organic framework (SnS2/ZnCo-MOF) nanocomposites in conjunction with gold nanoparticles (AuNPs) to co-modify a glassy carbon electrode (GCE). Further, a molecularly imprinted polymer (MIP)-based electrochemical sensing platform Au-MIP/SnS2/ZnCo-MOF/Au/GCE (AZG) was fabricated for selective CTC detection. SnS2/ZnCo-MOF enhanced the stability and surface area of the AZG sensor. The presence of AuNPs facilitated electron transport between the probe and the electrode across the insulating MIP layer. The fixation of AuNPs and MIP via electropolymerization enhanced the selective recognition of this sensor and amplified its output signal. The AZG sensor demonstrated a wide linear detection range (0.1-100 µM), low detection limit (0.072 nM), and high sensitivity (0.830 µA µM-1). It has been used for detecting CTC in animal-origin food with good recovery (96.08%-104.60%).


Assuntos
Clortetraciclina , Técnicas Eletroquímicas , Contaminação de Alimentos , Ouro , Nanopartículas Metálicas , Impressão Molecular , Ouro/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Nanopartículas Metálicas/química , Contaminação de Alimentos/análise , Animais , Clortetraciclina/análise , Estruturas Metalorgânicas/química , Compostos de Estanho/química , Limite de Detecção , Sulfetos/química , Antibacterianos/análise , Polímeros Molecularmente Impressos/química , Zinco/análise , Zinco/química
9.
Anal Methods ; 16(15): 2386-2399, 2024 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-38572640

RESUMO

A novel fluorescence sensor based on a porphyrinic zirconium-based metal-organic framework, L-cysteine-modified PCN-222 (L-Cys/PCN-222), was developed to selectively recognize histidine enantiomers and sensitively detect Hg2+. The dual-functional sensor was successfully prepared via the solvent-assisted ligand incorporation method and characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), 1H nuclear magnetic resonance (1H NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption analyses. L-Cys/PCN-222 not only showed a higher quenching response for L-histidine than that for D-histidine with a fast fluorescent response rate of <40 s but also exhibited low detection limits for L- and D-histidine (2.48 µmol L-1 and 3.85 µmol L-1, respectively). Moreover, L-Cys/PCN-222 was employed as a fluorescent and visual sensor for the highly sensitive detection of Hg2+ in the linear range of 10-500 µmol L-1, and the detection limit was calculated to be 2.79 µmol L-1 in surface water. The specific and selective recognition of chiral compounds and metal ions by our probe make it suitable for real field applications.


Assuntos
Mercúrio , Estruturas Metalorgânicas , Espectroscopia de Infravermelho com Transformada de Fourier , Histidina , Estruturas Metalorgânicas/química , Zircônio , Cisteína/análise , Cisteína/química , Corantes Fluorescentes/química , Mercúrio/análise
10.
RSC Adv ; 14(38): 28148-28159, 2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39228753

RESUMO

The excellent stability of covalent organic frameworks (COFs) and the diversity of metal organic frameworks (MOFs) make MOF/COF hybrid materials promising candidates for chromatographic stationary phases. In this paper, a TpBD/UiO-66-NH2 hybrid material was synthesized through a Schiff-base reaction between TpBD COFs and UiO-66-NH2 MOFs; characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy; and bonded to a capillary to prepare a TpBD/UiO-66-NH2-bonded open tubular capillary electrochromatography (OT-CEC) column. Results suggested that the hybrid material had the crystal morphology of a single COF and MOF, a micro-mesoporous structure, and good thermal stability. The inner surface of the OT-CEC column was tightly and uniformly distributed with the stationary phase (∼1.5 µm). The baseline separation of 13 amino acids and three families (4 acidic antibiotics, 4 preservatives and 6 sulfonamides) of emerging pollutant mixtures was achieved due to the synergistic effect of TpBD and UiO-66-NH2 in the stationary phase. The OT-CEC column showed good reproducibility and stability with relative standard deviations of migration time and resolutions in the range of 1.17-3.93% and 1.79-4.31%, respectively.

11.
Food Chem ; 418: 136001, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36989645

RESUMO

Olaquindox (OLA) in food from its illegal use possesses great harmful effects on humans, making it important to develop sensitive, inexpensive, and convenient methods for OLA detection. This study innovatively presented a molecularly imprinted electrochemical sensor based on the synergistic effects of nitrogen-doped graphene quantum dots (N-GQDs) and a nickel-based metal-organic framework functionalized with silver nanoparticles (Ag/Ni-MOF) for OLA detection. N-GQDs and Ag/Ni-MOF with unique honeycomb structures were sequentially modified on the glassy carbon electrode (GCE) surface to accelerate the electron transfer rate and increase the available region of the electrode. Molecularly imprinted polymers were further grown on the Ag/Ni-MOF/N-GQDs/GCE by electropolymerization to significantly enhance the selective recognition of OLA. The constructed sensor showed excellent performance for selective OLA determination, with a wide linear range (5-600 nmol·L-1) and exceedingly low detection limit (2.2 nmol·L-1). The sensor was successfully applied to detect OLA in animal-origin food with satisfactory recoveries (96.22-101.02%).


Assuntos
Grafite , Nanopartículas Metálicas , Impressão Molecular , Pontos Quânticos , Animais , Humanos , Carbono/química , Técnicas Eletroquímicas/métodos , Eletrodos , Alimentos , Análise de Alimentos , Grafite/química , Limite de Detecção , Nanopartículas Metálicas/química , Impressão Molecular/métodos , Nitrogênio , Polímeros/química , Pontos Quânticos/química , Prata/química , Níquel/química
12.
Heliyon ; 9(5): e16081, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37223711

RESUMO

Light harvesting based on a microporous zeolite imidazole backbone (MOF) has attracted considerable interest as a fluorescent sensor for the detection of analytes. In this work, we have prepared a novel complex containing quantum dots of doped rare earth elements by a one-pot method. to be applied to the fluorescence detection of pollution hazards. Because of the solid framework, the prepared ZnS:Eu@ZIF-8 composite shows desirable fluorescence properties. The selectivity and sensitivity of ZnS:Eu@ZIF -8 to TNP, which has a detection limit of 0.19 µmol/L, is further investigated and its sensing mechanism is discussed by means of fluorescence lifetime measurements in combination with emission and UV spectra. It should also be noted that this is the first doped quantum dot to be encapsulated in a MOF to be used for the potential detection of phenolic compounds in the aqueous environment, while the framework remains in place and no structural changes have occurred.

13.
Spectrochim Acta A Mol Biomol Spectrosc ; 291: 122370, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36680831

RESUMO

We report a post-synthesis modification for the preparation of a novel chiral fluorescent covalent organic framework (COF) for selective recognization of imazamox enantiomers. In this study, chiral COF was firstly synthesized via a Schiff-base reaction between 2,5-dihydroxyterephthalaldehyde (Dha) and 1,3,5-tris(4-aminophenyl)benzene (Tab) followed by a nucleophilic substitution using (1S)-(+)-10-camphorsulfonyl chloride as chiral modifier. The resulting regular spherical chiral COF Dha Tab not only presented the high optical efficiency, strong covalent bond structure, good crystallinity, large specific surface area but also showed the specific enantioselectivity and quick identification for imazamox enantiomers among five pesticide enantiomers (S/R-imazamox, acephate, acetochlor, propisochlor and metalaxyl). The detection limits for S- and R-imazamox were 4.20 µmol/L and 3.03 µmol/L, respectively. Meanwhile, the enantiomeric excess value (5.30 %) manifested that the chiral COF Dha Tab had the strong adsorption ability to imazamox enantiomers and more higher affinity for R-imazamox. This chiral fluorescent COF opened up a new way for the recognition of enantiomers.

14.
Biophys Chem ; 281: 106728, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34864227

RESUMO

The fabrication of cell models containing artificial cytosol is challenging. Herein we constructed an artificial cytosol contained cell model by electroformation method. Agarose was selected as the main component of the artificial cytosol, and sucrose was added into the agarose to regulate the sol viscosity and the phase transition temperature. The viscosity of the sol with the mass ratio (agarose-sucrose) 1:9 was closest to the natural cytosol. DSPC/20 mol% cholesterol was used to form large unilamellar vesicles (LUVs) as cell model compartment. The rhodamine release experiment confirmed that the unique release profile of agarose-sucrose@LUVs is suitable as a drug carrier. Doxorubicin is loaded in the agarose-sucrose@LUVs, and their half maximum inhibition concentration on HeLa cells is 0.016 µmol L-1, which means 28.7 times increase in inhibition efficiency over free doxorubicin.


Assuntos
Sistemas de Liberação de Medicamentos , Lipossomos , Citosol , Doxorrubicina/farmacologia , Células HeLa , Humanos , Sefarose , Sacarose , Lipossomas Unilamelares
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 270: 120829, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-34999355

RESUMO

In this paper, polyvinylpyrrolidone-templated copper nanoclusters (PVP-CuNCs) were synthesised using a hydrothermal method. Through the electrostatic interaction between PVP-CuNCs and rhodamine 6G, a dual-emission ratiometric fluorescent probe was constructed, and two well-separated emission peaks appeared at 420 nm and 570 nm. The selective detection of rutin and picric acid was achieved by fitting the relationship between the ratiometric fluorescence intensity (F420/F570) and the concentration of the target detection substance. The limits of detection of rutin and picric acid were 0.84 µM and 0.27 µM, respectively. The synthesised material has high stability and successfully allows the determination of rutin content in drugs and picric acid content in water samples with satisfactory recoveries.


Assuntos
Corantes Fluorescentes , Nanopartículas Metálicas , Cobre , Limite de Detecção , Picratos , Rutina , Espectrometria de Fluorescência
16.
Anal Methods ; 14(32): 3079-3086, 2022 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-35916293

RESUMO

p-Cresol is a harmful phenolic substance that can cause serious effects on human health even at a low concentration in water. Therefore, the detection of p-cresol in a water environment is particularly important. In this paper, a novel zeolite imidazolate framework-67 (ZIF-67) material with regular morphology was prepared on the surface of graphene oxide doped with silver nanoparticles. The composite was modified on the glassy carbon electrode surface to increase the specific surface area, accelerate the electron transfer rate, enhance the current response and improve the performance of electrochemical sensors. Furthermore, a layer of p-cresol-molecularly imprinted polymer was prepared on the surface of the modified electrode by electropolymerization for the selective, rapid and sensitive detection of p-cresol, which greatly improved the specific recognition of p-cresol. Under optimal conditions, the prepared sensor had a good linear range of 1.0 × 10-10 M to 1.0 × 10-5 M with a detection limit as low as 5.4 × 10-11 M, and it presented excellent reproducibility, stability and selectivity. Moreover, the sensor was successfully applied for the detection of trace p-cresol in a real water environment, providing a reliable assay for sensitive, rapid and selective detection of p-cresol in complex samples.


Assuntos
Nanopartículas Metálicas , Impressão Molecular , Zeolitas , Cresóis , Técnicas Eletroquímicas , Humanos , Limite de Detecção , Nanopartículas Metálicas/química , Reprodutibilidade dos Testes , Prata , Água
17.
ACS Omega ; 6(16): 10735-10744, 2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-34056227

RESUMO

Quantum dots (QDs) and carbon quantum dots (CDs) are classes of zero-dimensional materials whose sizes can be ≤10 nm. They exhibit excellent optical properties and are widely used to prepare fluorescent probes for qualitative and quantitative detection of test objects. In this article, we used cerium chloride as the cerium source and used the in situ doped cerium (rare-earth element) to develop cadmium telluride (CdTe) quantum dots following the aqueous phase method. CdTe: Ce quantum dots were successfully synthesized. The solution of CdTe:Ce QDs was mixed with the CD solution prepared following the green microwave method to form a ratio fluorescence sensor that can be potentially used for the selective detection of mercury ions (Hg2+). We used transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and other microscopy and spectral characterization techniques to validate that Ce had been successfully doped. The test results on the fluorescence performance revealed that Ce doping enhances the predoped fluorescence performance of the CdTe QDs. We have quantitatively detected Hg2+ using a ratiometric fluorescence sensor to show that in the range of 10-60 nM, the fluorescence quenching efficiency increases linearly with the increase in Hg2+ concentration. The linear correlation coefficient R 2 = 0.9978, and its detection limit was found to be 2.63 nM L-1. It was observed that other interfering ions do not significantly affect the fluorescence intensity of the probe. According to the results of the blank addition experiment, the developed proportional fluorescence probe can be used for the detection of Hg2+ in actual samples.

18.
ACS Omega ; 5(16): 9558-9565, 2020 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-32363308

RESUMO

Quantum dots (QDs) are a class of zero-dimensional nanocrystal materials, whose lengths are limited to 2-10 nm. Their unique advantages such as wide excitation spectra, narrow emission spectra, and high quantum yield make their application possible in fluorescence sensing, wherein QDs such as CdSe, CdTe, and CdS are used. Indeed, QDs have a wide range of applications in fluorescence sensing, and there have been many reports of applications based on QDs as ion probes. The emission spectra of QDs can be adjusted by changing the size of the QDs or doping them with other ions/elements. However, the high toxicity of Cd and the poor anti-interference ability of single-emission fluorescent probes greatly limit the applications of QDs in many fields. In this paper, ZnS QDs are doped with the rare-earth element Ce to form a low-toxicity double-emission ratiometric fluorescent sensor, ZnS:Ce, for Hg2+ detection. The results of transmission electron microscopy (TEM), X-ray diffractometry, X-ray photoelectron spectroscopy, and optical spectroscopy show that ZnS:Ce QDs were successfully synthesized. Under the optimal conditions, the concentration of Hg2+ was in the range of 10-100 µM, which had a linear relationship with the fluorescence intensity of the ZnS:Ce QDs: the linear correlation coefficient was 0.998, and the detection limit was 0.82 µM L-1. In addition, the fluorescent sensor had good selectivity for Hg2+, and it was successfully applied to the detection of Hg2+ in laboratory water samples.

19.
Int Immunopharmacol ; 86: 106687, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32570033

RESUMO

OBJECTIVE: KN motif and ankyrin repeat domains 2 (KANK2) may inhibit the activation of (NF-kappaB) p65, which plays a role in myocardial injury. Thus, our study aims to discover the effect of KANK2 on myocardial infarction (MI) induced by ligating the left anterior descending coronary artery (LAD) through regulating NF-κB p65 in vivo. METHODS: MI rats underwent LAD ligation were administered with intramyocardial injections of KANK2/Control activation plasmids. Six weeks after MI, pressure-volume (P/V) loops was used to investigate the cardiac function of rats, then the following detections were performed, including TTC staining, HE staining, immunofluorescence, Masson' s trichrome staining, ELISA assay, TUNEL staining, immunohistochemistry, qRT-PCR and Western blotting. RESULTS: MI rats decreased in maximum pressure (pmax), ejection fraction (EF%), peak rate of pressure rise (dpdtmax) and decline (-dpdtmax) with increased end diastolic pressure (EDP), which was partially reversed by KANK2 overexpression. Besides, KANK2 CRISPR activation plasmids reduced infarct size with less collagen fiber proliferation and neutrophil infiltration in infarct tissues, as well as suppressed pro-inflammatory factors expressions in MI rats. Moreover, injection of KANK2 activation plasmid decreased collagen deposition, aggravated cardiomyocyte apoptosis, enhanced the capillary density, and increased the expressions of VEGF and bFGF in the infarct and peri-infarct regions of MI rats. KANK2 lowered myocardial NF-κB p65 expression in MI rats. CONCLUSION: KANK2 may play its therapeutic role in MI through improving cardiac function, decreasing myocardial collagen deposition, reducing cardiomyocyte apoptosis, and increasing angiogenesis, which might be associated with the reduction of NF-κB p65 expression.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Infarto do Miocárdio/metabolismo , Fator de Transcrição RelA/antagonistas & inibidores , Animais , Apoptose/genética , Capilares/crescimento & desenvolvimento , Colágeno/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Fator 2 de Crescimento de Fibroblastos/metabolismo , Infarto do Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Ratos Sprague-Dawley , Fator de Transcrição RelA/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Função Ventricular Esquerda
20.
ACS Omega ; 5(13): 7369-7378, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32280878

RESUMO

In this work, coumarin derivatives (C) are used to enhance the fluorescence of graphene quantum dots (GQDs) by covalently linking the carboxyl groups on the edge of the GQD sheet. The as-synthesized coumarin-modified graphene quantum dots (C-GQDs) have a uniform particle size with an average diameter of 3.6 nm. Simultaneously, the C-GQDs have strong fluorescence emission, excellent photostability, and high fluorescence quantum yield. C-GQDs and CN- can form a C-GQDs+CN- system due to deprotonation and/or intermolecular interactions. The introduced hydroquinone (HQ) is oxidized to benzoquinone (BQ), and the interaction between BQ and the C-GQDs+CN- system could lead to fluorescence enhancement of C-GQDs. Meanwhile, the redox reaction between BQ and ascorbic acid (AA) can be used for quantitative detection of AA with CN- and HQ being used as substrates. Based on the above mechanism, C-GQDs are developed as a multicomponent detection and sensing platform, and the detection limits for CN-, HQ, and AA were 4.7, 2.2, and 2.2 nM, respectively. More importantly, satisfactory results were obtained when the platform was used to detect CN-, HQ, and AA in living cells and fresh fruits.

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