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1.
J Chem Phys ; 151(14): 144706, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615228

RESUMO

Quantum dot (QD) biological imaging and sensing applications often require surface modification with single-stranded deoxyribonucleic acid (ssDNA) oligonucleotides. Furthermore, ssDNA conjugation can be leveraged for precision QD templating via higher-order DNA nanostructures to exploit emergent behaviors in photonic applications. Use of ssDNA-QDs across these platforms requires compact, controlled conjugation that engenders QD stability over a wide pH range and in solutions of high ionic strength. However, current ssDNA-QD conjugation approaches suffer from limitations, such as the requirement for thick coatings, low control over ssDNA labeling density, requirement of large amounts of ssDNA, or low colloidal or photostability, restraining implementation in many applications. Here, we combine thin, multidentate, phytochelatin-3 (PC3) QD passivation techniques with strain-promoted copper-free alkyne-azide click chemistry to yield functional ssDNA-QDs with high stability. This process was broadly applicable across QD sizes (i.e., λem = 540, 560, 600 nm), ssDNA lengths (i.e., 10-16 base pairs, bps), and sequences (poly thymine, mixed bps). The resulting compact ssDNA-QDs displayed a fluorescence quenching efficiency of up to 89% by hybridization with complementary ssDNA-AuNPs. Furthermore, ssDNA-QDs were successfully incorporated with higher-order DNA origami nanostructure templates. Thus, this approach, combining PC3 passivation with click chemistry, generates ssDNA-PC3-QDs that enable emergent QD properties in DNA-based devices and applications.


Assuntos
DNA de Cadeia Simples/química , Nanocompostos/química , Pontos Quânticos/química , Alquinos/química , Azidas/química , Compostos de Cádmio/química , Química Click , Fluorescência , Ouro/química , Nanopartículas Metálicas/química , Hibridização de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Fitoquelatinas/química , Poli T/química , Compostos de Selênio/química , Sulfetos/química , Propriedades de Superfície , Compostos de Zinco/química
2.
Int J Nanomedicine ; 14: 7065-7078, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31507320

RESUMO

Background:  Metal-free, water-soluble and highly stable meso-tetra-(4-sulfonatophenyl) porphyrin (TPPS4) has been studied for their singlet oxygen quantum yield. However, TPPS4 suffers from inherent shortcomings. To address these, TPPS4 was conjugated to ternary copper indium sulphide/ zinc sulphide (CuInS2/ZnS) quantum dots (QDs). Purpose:  We herein report for the first time the synthesis of TPPS4-CuInS/ZnS QDs conjugate as an improved photosensitizer. Methods:  Water-soluble TPPS4 was synthesized from tetraphenylporphyrin (TPPH2) after silica-gel purification. The CuInS/ZnS QDs were synthesized by hydrothermal method at a Cu:In ratio of 1:4. The porphyrin-QDs conjugate was formed via the daggling sulfonyl bond of the porphyrin and amine bond of the QDs. The effect of pH on the optical properties of TPPS4 was evaluated. The effect of Zn:Cu + In ratio on the ZnS shell passivation was examined to reduce structural defects on the as-synthesized QDs. Results : Various spectroscopic techniques were used to confirm the successful conversion of the organic TPPH2 to water-soluble TPPS4. The singlet oxygen generation evaluation shows an improved singlet oxygen quantum yield from 0.19 for the porphyrin (TPPS4) alone to 0.69 after conjugation (CuInS/ZnS-TPPS4) with an increase in the reaction rate constant (k (s-1)).


Assuntos
Cobre/química , Índio/química , Porfirinas/síntese química , Porfirinas/farmacologia , Pontos Quânticos/química , Sulfetos/síntese química , Compostos de Zinco/síntese química , Concentração de Íons de Hidrogênio , Fenômenos Ópticos , Fármacos Fotossensibilizantes , Porfirinas/química , Pontos Quânticos/ultraestrutura , Oxigênio Singlete/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos/química , Temperatura Ambiente , Compostos de Zinco/química
3.
Anal Bioanal Chem ; 411(21): 5437-5444, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31300858

RESUMO

To meet the need for high-throughput immunoassays, many multiplex fluorescent immunoassays have been proposed. Most of them need different kinds of fluorescent label indicators during the test. In this work, a novel indirect ELISA-inspired dual-channel fluorescent immunoassay based on 3-mercaptopropionic acid capped CdTe/ZnS quantum dots (QDs) was constructed. The ELISA wells were coated with two kinds of antigen-QD complex. When the primary antibodies were present in a sample, they mediated the binding of a secondary antibody-DNA-gold nanoparticle complex to the antigen-QD complex. Then the gold nanoparticles quenched the fluorescence of the QDs and a decrease in fluorescence intensity was observed. Thus, the amount of primary antibody could be estimated from the decrease of fluorescence intensity. Owing to the wide absorption range and the relatively narrow emission band of the QDs, the dual-channel fluorescent immunoassay system could work at the same excitation wavelength and the emission wavelengths of each channel had no interference. As a result, two different kinds of primary antibody could be detected at the same time in one ELISA well, which simplified the operation and greatly improved the efficiency. Besides, only one type of secondary antibody needs to be added to the prepared microtiter plates, which further simplified the operation during the detection procedure. This dual-channel fluorescent immunoassay system will provide new insights into high-throughput immunodetection. Graphical abstract.


Assuntos
Compostos de Cádmio/química , Ensaio de Imunoadsorção Enzimática/métodos , Imunofluorescência/métodos , Pontos Quânticos , Sulfetos/química , Telúrio/química , Compostos de Zinco/química , Nanopartículas Metálicas/química , Microscopia Eletrônica de Transmissão
4.
J Agric Food Chem ; 67(25): 6970-6977, 2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31150237

RESUMO

Huanglongbing (HLB), also known as citrus greening, is a bacterial disease that poses a devastating threat to the citrus industry worldwide. To manage this disease efficiently, we developed and characterized a ternary aqueous solution (TSOL) that contains zinc nitrate, urea, and hydrogen peroxide. We report that TSOL exhibits better antimicrobial activity than commercial bactericides for growers. X-ray fluorescence analysis demonstrates that zinc is delivered to citrus leaves, where the bacteria reside. FTIR and Raman spectroscopy, molecular dynamics simulations, and density functional theory calculations elucidate the solution structure of TSOL and reveal a water-mediated interaction between Zn2+ and H2O2, which may facilitate the generation of highly reactive hydroxyl radicals contributing to superior antimicrobial activity of TSOL. Our results not only suggest TSOL as a potent antimicrobial agent to suppress bacterial growth in HLB-infected trees, but also provide a structure-property relationship that explains the superior performance of TSOL.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Citrus/microbiologia , Nitratos/química , Nitratos/farmacologia , Doenças das Plantas/prevenção & controle , Rhizobiaceae/fisiologia , Compostos de Zinco/química , Compostos de Zinco/farmacologia , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/farmacologia , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Rhizobiaceae/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Relação Estrutura-Atividade , Ureia/química , Ureia/farmacologia
5.
Anal Bioanal Chem ; 411(20): 5277-5285, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31161325

RESUMO

Rapid, highly sensitive detection of tau protein and other neurodegenerative biomarkers remains a significant hurdle for diagnostic tests for Alzheimer's disease. In this work, we developed a novel tyrosinase (TYR)-induced tau aptamer-tau-tau antibody (anti-tau) sandwich fluorescence immunoassay to detect tau protein that used dopamine (DA)-functionalized CuInS2/ZnS quantum dots as the fluorophore. CuInS2/ZnS core/shell quantum dots with high luminescence, low toxicity, and excellent biocompatibility were successfully fabricated and decorated with DA through amide conjugation. Meanwhile, TYR was conjugated with anti-tau by a click reaction. When DA-functionalized CuInS2/ZnS quantum dots were added to the sandwich system, TYR catalyzed the transformation of DA to dopamine quinone, which acted as an effective electron acceptor and triggered fluorescence quenching. The fluorescence intensity of the immunoassay based on DA-functionalized CuInS2/ZnS quantum dots shows good performance in terms of linearity with the logarithm of tau protein concentration, with a linear concentration range from 10 pM to 200 nM. This work is the first to use a TYR-induced fluorescence immunoassay for the rapid detection of tau protein, paving a new way for the detection of disease biomarkers. Graphical abstract.


Assuntos
Cobre/química , Imunofluorescência/métodos , Índio/química , Monofenol Mono-Oxigenase/química , Pontos Quânticos/química , Selênio/química , Sulfetos/química , Compostos de Zinco/química , Proteínas tau/análise , Cristalografia por Raios X , Dopamina/análogos & derivados , Dopamina/química , Microscopia Eletrônica de Transmissão , Análise Espectral/métodos
6.
Environ Sci Pollut Res Int ; 26(24): 24850-24862, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31240644

RESUMO

Bisphenol-A is widely used chemical in industry and unfortunately often detected in natural waters. Considered as an emerging pollutant, bisphenol-A represents an environmental problem due to its endocrine-disrupting behavior. The production of activated carbon from alternative precursors has shown to be attractive in the removal of emerging pollutants from the water. Activated carbon was produced from waste coffee by physical and chemical activation and applied in the removal of bisphenol-A. The samples were characterized by elemental analysis, scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and analysis of textural properties. Bisphenol-A adsorption experiments showed that the chemically activated carbon was more efficient due to its high specific surface area (1039 m2/g) compared to the physically activated carbon (4.0 m2/g). The bisphenol-A adsorption data followed the pseudo-second-order model and Langmuir isotherm, which indicated a maximum adsorption capacity of 123.22 mg/g for chemically activated carbon. The results demonstrated a potential use of the coffee grounds as a sustainable raw material for the production of chemically activated carbon that could be used in water treatment.


Assuntos
Compostos Benzidrílicos/isolamento & purificação , Carvão Vegetal/química , Café , Fenóis/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Compostos Benzidrílicos/química , Cloretos/química , Cinética , Microscopia Eletrônica de Varredura , Fenóis/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resíduos , Poluentes Químicos da Água/química , Purificação da Água/métodos , Difração de Raios X , Compostos de Zinco/química
7.
Analyst ; 144(13): 4086-4092, 2019 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-31169832

RESUMO

Given that Helicobacter pylori (H. pylori) generally infects people in early childhood and that such persons when not treated with antibiotics remain infected for the rest of their lives, it is quite important to detect H. pylori in children, and convenient to do so using non-invasive methods. Stool antigen tests constitute such an effective non-invasive method. In the current work, a novel fecal test was developed to detect H. pylori based on immunomagnetic beads (IMBs) with monoclonal antibodies sensitively recognizing and capturing the H. pylori, coupled with a polyclonal antibody-conjugating quantum dot probe, and ultrasensitive detection was achieved by using a fluorescence spectrometer. The detection method took 120 min to perform, and showed a limit of detection of 102 CFU mL-1 and a linear range of 10 to 106 CFU mL-1 (R2 = 0.9962). Most importantly, this method can be effectively applied to real samples. This study provided a novel method for the non-invasive detection of the fecal antigen H. pylori.


Assuntos
Fezes/microbiologia , Helicobacter pylori/isolamento & purificação , Pontos Quânticos/química , Espectrometria de Fluorescência/métodos , Animais , Anticorpos Monoclonais Murinos/imunologia , Cádmio/química , Helicobacter pylori/imunologia , Humanos , Separação Imunomagnética/métodos , Limite de Detecção , Camundongos , Coelhos , Selênio/química , Sulfetos/química , Compostos de Zinco/química
8.
Chem Commun (Camb) ; 55(54): 7852-7855, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31215553
9.
Environ Sci Pollut Res Int ; 26(24): 24630-24644, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31240649

RESUMO

Trace metal element contamination in mining areas is always a huge environmental challenge for the global mining industry. In this study, an abandoned sphalerite mine near the Yanshan Mountains was selected as subject to evaluate the soil and water contamination caused by small-scale mining. The results show that (1) Pearson correlation matrix and principal component analysis (PCA) results reveal that Zn, Cu, Cd, and Pb were greatly affected by the operation of mines, especially mineral tailings. The contents of trace metal elements decrease with the increase of the distance from the mining area. Zinc, Pb, and Cd were discovered in almost all soil samples, and Zn accounted for about 80% of pollution of the topsoil. (2) The trace element pollution levels in the topsoil of the three villages were ranked as follows: Cd > Cu > Pb~Zn. The potential ecological risk of farmland around the mine ranges from lower to higher, with Cd being the most harmful. (3) Human health risk assessment results show that trace elements in the mining area pose obvious non-carcinogenic health risks to children while the risks to adults are not equally obvious. The carcinogenic risk of Cd and Cr is within a safe range and does not pose an obvious cancer risk to the population.


Assuntos
Poluentes do Solo/análise , Sulfetos/química , Oligoelementos/análise , Compostos de Zinco/química , Zinco/análise , Adulto , Criança , China , Ecologia , Poluição Ambiental/análise , Humanos , Mineração , Medição de Risco , Solo , Poluentes do Solo/química , Oligoelementos/química , Recursos Hídricos , Zinco/química
10.
Talanta ; 202: 230-236, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171175

RESUMO

Rapid and non-destructive detection of circulating tumor cells (CTCs) with no disruption of their functions is of great significance for clinical tumor therapy. However, many existing methods for CTC detection commonly rely on conventional three-color immunofluorescence identification, which damages CTCs and easily causes loss of cells. Here, we employed a method to simultaneously capture and authenticate CTCs based on immunonanocomposites (ZnS:Mn2+ QDs and Fe3O4/SiO2) equipped with permanent fluorescent and magnetic properties. A multifunctional nanocomposite was synthesized by encapsulating ZnS:Mn2+ quantum dots (QDs) and Fe3O4 nanoparticles into SiO2 nanospheres and bio-conjugating tumor-specific anti-EpCAM antibodies onto the surface. The resulting nanocomposite had a high tumor cell binding ability, and the Fe3O4 nanoparticles had a rapid magnetic response that enabled capture of circulating tumor cells from patients' blood within minutes. In addition, the cell-immunonanocomposites complexes could be directly recognized by the yellow-orange light emitted by the ZnS:Mn2+ quantum dots, thus labeling cells without utilizing the complicated and destructive procedures involved in traditional CTCs identification. We successfully achieved a high capture efficiency of up to 90.8%, and the specific fluorescence labeling of CTCs was realized in 9 clinical breast cancer patients' samples. Furthermore, this simple, convenient and cell-friendly approach is significant for solving the problems of cell viability and enables non-destructive CTC detection, which marks an advance in cancer treatment and clinical applications.


Assuntos
Nanopartículas de Magnetita/química , Manganês/química , Células Neoplásicas Circulantes/patologia , Pontos Quânticos/química , Sulfetos/química , Compostos de Zinco/química , Linhagem Celular , Humanos , Tamanho da Partícula , Propriedades de Superfície
11.
Chemosphere ; 230: 406-415, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31112863

RESUMO

Norfloxacin (NOR) is an emerging antibiotics contaminant due to its high resistance to microbial degradation and natural weathering. In this study, Fe-doped ZnS photocatalyst (Zn0.9Fe0.1S) was deposited on nickel foam (Ni-foam) to improve photocatalytic activity under visible light irradiation. The mass ratio of Zn0.9Fe0.1S and Ni-foam was optimized to be 0.03 g catalyst versus per g Ni-foam (0.03 Zn0.9Fe0.1S/Ni-foam), which led to the highest removal rate of 95%. The optimal degradation condition for NOR over 0.03 Zn0.9Fe0.1S/Ni-foam was pH at 7.0, initial NOR concentration of 5 mg L-1, and initial photocatalyst concentration of 11.7 g L-1, with the highest first-order reaction rate constant of 0.025 min-1 and mineralization rate of 63.1%. The NOR removal rate on 0.03 Zn0.9Fe0.1S/Ni-foam photocatalyst (95%) was approximately four times of that obtained on Zn0.9Fe0.1S photocatalyst (25%). The increased photocatalytic performance could be attributed to the function of Ni-foam as excellent electron collectors that provided efficient photoinduced charge separation from Zn0.9Fe0.1S. The reactive species responsible for the degradation of NOR were photo-generated holes, hydroxyl radical, and superoxide radicals. Nearly 90% of the photocatalytic efficiency was retained over seven cycles and the released metal ion concentrations were <0.3% of the total mass of photocatalyst, suggesting high stability of the photocatalyst during the photocatalytic reactions. The aqueous/solid mass transfer and intraparticle mass transfer for Zn0.9Fe0.1S/Ni-foam were not limiting factors for the degradation of NOR. Therefore the Zn0.9Fe0.1S/Ni-foam photocatalyst could be applied in the degradation of hazardous pollutants.


Assuntos
Ferro/química , Luz , Níquel/química , Norfloxacino/análise , Oxidantes Fotoquímicos/química , Sulfetos/química , Poluentes Químicos da Água/análise , Compostos de Zinco/química , Catálise , Norfloxacino/efeitos da radiação , Oxirredução , Poluentes Químicos da Água/efeitos da radiação
12.
Anal Bioanal Chem ; 411(20): 5223-5231, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31111180

RESUMO

The visualization of subcellular structures is critical for understanding their intracellular function. We prepared two triarylboron-based multinuclear Zn2+ complexes, TAB-1-3Zn2+ and TAB-2-2Zn2+, which can be used as fluorescent probes for nucleoside polyphosphate (NPP) and RNA because their multi Zn2+ center can selectively combine with the phosphate side chain of NPP or RNA, accompanied by a corresponding fluorescence change. Among them, TAB-2-2Zn2+ is more suitable than TAB-1-3Zn2+ for live cell imaging because of its excellent cell membrane permeability resulting from amphiphilicity. Since the various membrane structures in cells are also composed of phosphoric acid bilayers, TAB-2-2Zn2+ may also be used to image various membrane structures. Various colocalization experiments further confirmed that TAB-2-2Zn2+ can achieve clear simultaneous imaging of the cell membrane, the endoplasmic reticulum, and the nucleolus. Graphical abstract.


Assuntos
Compostos de Boro/química , Membrana Celular/metabolismo , Nucléolo Celular/metabolismo , Complexos de Coordenação/química , Retículo Endoplasmático/metabolismo , Corantes Fluorescentes/química , Compostos de Zinco/química , Células 3T3 , Animais , Células HeLa , Células Hep G2 , Humanos , Camundongos , Fótons , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Frações Subcelulares/metabolismo
13.
Carbohydr Polym ; 217: 190-198, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31079676

RESUMO

In this study, an improved facile cellulose dissolution with low chemical concentration process was used for preparing corn stalk pith regenerated cellulose (RC) films. The conventional method usually requires 68% zinc chloride solution for cellulose dissolution. The objective of this study is produced corn stalk pith RC films by using a low-concentration zinc chloride solution with improved thermal stability. The major weight loss peak temperature of RC films was increased from 231 °C to 307 °C as the crystallinity indexes increased from 48.30% to 53.19% by decreased the concentration of zinc chloride solution from 65% to 45%, respectively. The increased thermal stability can create new opportunities for the development of RC films dissolving by zinc chloride solution.


Assuntos
Celulose/química , Cloretos/química , Zea mays/química , Compostos de Zinco/química , Química Verde/métodos , Membranas Artificiais , Permeabilidade , Porosidade , Solubilidade , Vapor , Temperatura Ambiente , Resistência à Tração , Água/química
14.
Int J Mol Sci ; 20(10)2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31091667

RESUMO

Olive mill wastewater (OMW) is the aqueous waste derived from the production of virgin olive oil. OMW typically contains a wide range of phenol-type molecules, which are natural antioxidants and/or antibacterials. In order to exploit the bioactive molecules and simultaneously decrease the environmental impact of such a food waste stream, OMW has been intercalated into the host structure of ZnAl layered double hydroxide (LDH) and employed as an integrative filler for the preparation of poly(butylene succinate) (PBS) composites by in situ polymerization. From the view point of the polymer continuous phase as well as from the side of the hybrid filler, an investigation was performed in terms of molecular and morphological characteristics by gel permeation chromatography (GPC) and X-ray diffraction (XRD); also, the thermal and mechanical properties were evaluated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic thermomechanical analysis (DMTA). Antibacterial properties have been assessed against a Gram-positive and a Gram-negative bacterium, Staphylococcus aureus and Escherichia coli, respectively, as representatives of potential agents of foodborne illnesses.


Assuntos
Antibacterianos/química , Embalagem de Alimentos/métodos , Hidróxidos/química , Nanocompostos/química , Azeite de Oliva/química , Águas Residuárias/química , Compostos de Zinco/química , Antibacterianos/farmacologia , Butileno Glicóis/química , Polimerização , Polímeros/química , Staphylococcus aureus/efeitos dos fármacos
15.
Int J Mol Sci ; 20(10)2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31091724

RESUMO

Low-frequency electron paramagnetic resonance (EPR) spectra were obtained for the Co complex of ethylene diamine tetraacetic acid (CoEDTA). It was found that the cobalt hyperfine at geff-mid is better resolved at a low frequency, L-band (1.37 GHz), and not resolved at X-band (9.631 GHz), which is the conventional frequency used for most spectra for metal complexes. Resolved cobalt hyperfine lines lead to additional EPR parameters like A-mid for cobalt and a more-accurate determination of g-mid. Resolved hyperfine lines in the L-band, but not the S-band, spectra were obtained at a concentration of 1 mM. Knowing these additional EPR parameters provides a means to better determine the electron density in the ground state orbital for each cobalt complex, as well as to determine differences upon a change of ligation. If zinc sites can be replaced by cobalt, the cobalt spectra for these sites will enhance the characterization of the zinc sites.


Assuntos
Cobalto/química , Ácido Edético/química , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Compostos de Zinco/química
16.
Analyst ; 144(12): 3892-3897, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31120053

RESUMO

Mercury, as one of the most prevalent toxic metals released by various natural and anthropogenic processes, causes severe pollution of soil and groundwater. In this work, R-phycoerythrin (R-PE) proteins encapsulated into ZIF-8 composite thin films were prepared via a solid-confinement conversion process and applied as fluorescent sensors for mercury ion detection. The R-PE proteins encapsulated into ZIF-8 exhibit dual color emissions including green (518 nm) and red (602, 650 nm) fluorescence, while the original orange emission (578 nm) of pure R-PE is significantly suppressed. R-PE@ZIF-8 presents excellent selectivity and sensitivity for mercury detection in a large pH range without buffer solution. Under the optimal conditions, there is a good linear relationship between the fluorescence quenching efficiencies of R-PE@ZIF-8 and logarithmic concentrations of mercury ions in the range of 0.001-50 µM with the detection limit (LOD) of 6.7 nM much lower than the guideline value given by the World Health Organization. Furthermore, multi-peak detection of R-PE@ZIF-8 improves the detection accuracy of Hg2+ concentration.


Assuntos
Mercúrio/análise , Estruturas Metalorgânicas/química , Ficoeritrina/química , Fluorescência , Hidróxidos/química , Limite de Detecção , Membranas Artificiais , Porphyra/química , Espectrometria de Fluorescência/métodos , Compostos de Zinco/química
17.
Int J Mol Sci ; 20(9)2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31032813

RESUMO

We report here the reaction of in situ prepared PhSeZnCl with steroid derivatives having an epoxide as an electrophilic functionalization. The corresponding ring-opening reaction resulted to be regio- and stereoselective affording to novel phenylselenium-substituted steroids. Assessment of their antibacterial properties against multidrug-resistant bacteria, such as Pseudomonas aeruginosa Xen 5 strain, indicates an interesting bactericidal activity and their ability to prevent bacterial biofilm formation.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Cloretos/química , Compostos Organosselênicos/química , Compostos Organosselênicos/farmacologia , Esteroides/química , Compostos de Zinco/química , Antibacterianos/síntese química , Biofilmes/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Compostos Organosselênicos/síntese química , Pseudomonas aeruginosa/efeitos dos fármacos
18.
Molecules ; 24(7)2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30986969

RESUMO

Selective oxidation of α-hydroxy esters is one of the most important methods to prepare high value-added α-keto esters. An efficient catalytic system consisting of Zn(NO3)2/VOC2O4 is reported for catalytic oxidation of α-hydroxy esters with molecular oxygen. Up to 99% conversion of methyl DL-mandelate or methyl lactate could be facilely obtained with high selectivity for its corresponding α-keto ester under mild reaction conditions. Zn(NO3)2 exhibited higher catalytic activity in combination with VOC2O4 compared with Fe(NO3)3 and different nitric oxidative gases were detected by situ attenuated total reflection infrared (ATR-IR) spectroscopy. UV-vis and ATR-IR results indicated that coordination complex formed in Zn(NO3)2 in CH3CN solution was quite different from Fe(NO3)3; it is proposed that the charge-transfer from Zn2+ to coordinated nitrate groups might account for the generation of different nitric oxidative gases. The XPS result indicate that nitric oxidative gas derived from the interaction of Zn(NO3)2 with VOC2O4 could be in favor of oxidizing VOC2O4 to generate active vanadium (V) species. It might account for different catalytic activity of Zn(NO3)2 or Fe(NO3)3 combined with VOC2O4. This work contributes to further development of efficient aerobic oxidation under mild reaction conditions.


Assuntos
Ésteres/química , Nitratos/química , Oxigênio/química , Vanadatos/química , Compostos de Zinco/química , Catálise , Estrutura Molecular , Oxirredução
19.
Talanta ; 199: 65-71, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30952310

RESUMO

Synthesized molecularly imprinted polymer (MIP) materials have been anchored on the surface of PEG-Mn-doped ZnS quantum dots (QDs) to develop a fluorescence probe for aflatoxins (AFs) recognition/determination in non-dairy beverages. MIP synthesis used 5,7-dimethoxycoumarin (DMC) as a dummy template molecule, and methacrylic acid (MAA) as a functional monomer. Under optimized conditions (1.25 mL of 5 mg L-1 MIP-PEG-ZnS QDs solution, pH 5.0, and 12 min delay time before scanning), the prepared MIP-QDs composite was found to offer high affinity and selectivity for AFs (AFB1, AFB2, AFG1 and AFG2). A fast fluorimetric screening method (total AFs assessment) was therefore feasible. The limits of detection (LOD) and quantification (LOQ) were 0.016 and 0.053 mg L-1, respectively. Analytical recoveries (inter- and intra-day assays) were from 99 ±â€¯4% to 107 ±â€¯5%, with RSD (intra-day assay) lower than 13, and RSD (inter-day) lower than 7%. The optimized method was applied for total AFs assessment in several non-dairy beverage samples.


Assuntos
Aflatoxinas/análise , Bebidas/análise , Corantes Fluorescentes/química , Impressão Molecular , Polímeros/química , Pontos Quânticos/química , Manganês/química , Sulfetos/química , Compostos de Zinco/química
20.
Chemosphere ; 227: 505-513, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31004817

RESUMO

The existence of Cr(VI) and antibiotics in the environment can form the joint contaminant which can be hazardous to the ecosystem. To deal with this, we have explored a plausible method to remove the Cr(VI) and tetracycline (TC) from water by visible light photocatalysis. In this study, a series of reduced graphene oxide@ZnAlTi layered double oxides (rGO@LDO) composites with different doping ratio of rGO were successfully synthesized, which were applied in photocatalytic reduction of Cr(VI) and oxidation of TC. Graphene acts as an electron donor and it can enhance the adsorption of Cr(VI) and TC on the surface of the composites. It's found that the obtained ZnAlTi-LDO composites doped with rGO have higher photo-responsiveness in the visible region. The best-performing rGO@LDO composite (i.e., CGL3) exhibited enhanced visible light-driven photocatalytic Cr(VI) reduction, which was about five times higher than those of ZnAlTi-LDO (without adding hole catcher). The rGO@LDO also showed a satisfactory performance for photocatalytic oxidation of TC with the total organic carbon removal of 80%. However, the doping of rGO did not significantly enhance the removal of TC. The experiment of pH effects demonstrated that acidic pH was favorable to photocatalytic reduction of Cr(VI), while neutral pH was favorable to photocatalytic oxidation of TC. The band structure of ZnAlTi-LDO was first identified, and the EVB and ECB of ZnAlTi-LDO are -2.32 and 0.72 V (vs. RHE). This research provides a feasible method to remove Cr(VI) and tetracycline from water by employing ZnAlTi-LDO doped with rGO as photocatalyst.


Assuntos
Cromo/isolamento & purificação , Grafite/química , Luz , Óxidos/síntese química , Tetraciclina/isolamento & purificação , Adsorção , Catálise , Concentração de Íons de Hidrogênio , Oxirredução , Óxidos/química , Poluentes Químicos da Água/química , Compostos de Zinco/química
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