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1.
Macromol Rapid Commun ; 41(6): e1900586, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32022359

RESUMO

Orthogonal dynamic covalent self-assembly is used as a facile method for constructing polymer hollow nanocapsules (NCs) and thin films. The bifunctional precursor 4-formylphenylboronic acid is symmetrically installed with a boronic acid group for the boroxine linkage, and an aldehyde group for the Schiff base reaction which can react with twofold symmetry linkers ethylenediamine and para phenylenediamine to attain polymer NCs and nanosheets. Owing to the reversibility of the imine linkages, the mutual morphological transformation between polymer NCs and thin films via an amine-imine-exchange strategy is successfully achieved. Multiple reversible covalent bonds allow the control the release of the load in polymer NCs using different techniques. This may be useful for designing stimulus-responsive smart materials.


Assuntos
Benzaldeídos/química , Ácidos Borônicos/química , Etilenodiaminas/química , Iminas/química , Nanocápsulas/química , Fenilenodiaminas/química , Polímeros/química , Polímeros/síntese química , Aldeídos/química , Aminas/química , Nanocápsulas/ultraestrutura , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Bases de Schiff/química , Propriedades de Superfície
2.
Chem Commun (Camb) ; 56(20): 3047-3049, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32048688

RESUMO

A series of aminocarboxylic acid analogues of aspergillomarasmine A (AMA) and ethylenediamine-N,N'-disuccinic acid (EDDS) were chemoenzymatically synthesized via the addition of various mono- and diamine substrates to fumaric acid catalyzed by the enzyme EDDS lyase. Many of these novel AMA and EDDS analogues demonstrate potent inhibition of the bacterial metallo-ß-lactamase NDM-1. Isothermal titration calorimetry assays revealed a strong correlation between the inhibitory potency of the compounds and their ability to bind zinc. Compounds 1a (AMA), 1b (AMB), 5 (EDDS), followed by 1d and 8a, demonstrate the highest synergy with meropenem resensitizing an NDM-1 producing strain of E. coli to this important carbapenem of last resort.


Assuntos
Ácido Aspártico/análogos & derivados , Complexos de Coordenação/farmacologia , Proteínas de Escherichia coli/antagonistas & inibidores , Etilenodiaminas/farmacologia , Succinatos/farmacologia , Zinco/farmacologia , Inibidores de beta-Lactamases/farmacologia , Aminoácidos/química , Aminoácidos/farmacologia , Ácido Aspártico/química , Ácido Aspártico/farmacologia , Complexos de Coordenação/síntese química , Complexos de Coordenação/química , Relação Dose-Resposta a Droga , Proteínas de Escherichia coli/metabolismo , Etilenodiaminas/química , Estrutura Molecular , Relação Estrutura-Atividade , Succinatos/química , Zinco/química , Inibidores de beta-Lactamases/síntese química , Inibidores de beta-Lactamases/química , beta-Lactamases/metabolismo
3.
Molecules ; 25(2)2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31936104

RESUMO

Metallation of biomacromolecular species forms the basis for the anticancer activity of many metallodrugs. A major limitation of these compounds is that their reactivity is indiscriminate and can, in principle, occur in healthy tissue as well as cancerous tissue, potentially leading to side effects in vivo. Here we present pH-dependent intramolecular coordination of an arene-tethered sulfonamide functionality in organometallic ruthenium(II) ethylenediamine complexes as a route to controlling the coordination environment about the central metal atom. Through variation of the sulfonamide R group and the length of the tether linking it to the arene ligand the acidity of the sulfonamide NH group, and hence the pH-region over which regulation of metal coordination occurs, can be modulated. Intramolecular sulfonamide ligation controlled the reactivity of complex 4 within the physiologically relevant pH-region, rendering it more reactive towards 5'-GMP in mildly acidic pH-conditions typical of tumour tissue compared to the mildly alkaline pH-conditions typical of healthy tissue. However, the activation of 4 by ring-opening of the chelate was found to be a slow process relative to the timescale of typical cell culture assays and members of this series of complexes were found not to be cytotoxic towards the HT-29 cell line. These complexes provide the basis for the development of analogues of increased potency where intramolecular sulfonamide ligation regulates reactivity and therefore cytotoxicity in a pH-dependent, and potentially, tissue-dependent manner.


Assuntos
Antineoplásicos/química , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Diaminas/química , Compostos Organometálicos/farmacologia , Rutênio/química , Sulfonamidas/química , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Quelantes/química , Complexos de Coordenação/síntese química , Complexos de Coordenação/toxicidade , Cristalografia por Raios X , Diaminas/farmacologia , Etilenodiaminas/química , Etilenodiaminas/farmacologia , Guanosina Monofosfato/metabolismo , Células HT29 , Humanos , Concentração de Íons de Hidrogênio , Cinética , Ligantes , Modelos Moleculares , Compostos Organometálicos/química , Rutênio/farmacologia , Sulfonamidas/farmacologia
4.
Artigo em Inglês | MEDLINE | ID: mdl-31941097

RESUMO

Adding chelating agents is a critical technique of heavy metal activation for enhancing phytoextraction through the formation of soluble metal complexes which will be more readily available for extraction. The preliminary, dynamic, equilibrium activation experiments and speciation analysis of Pb, Cd and Tl in contaminated red soils were used to select six chelates with relatively good activation performance from nine chelates, and the effects of dosage and pH on the heavy metals activation were studied systematically. Results showed that the activation of Pb, Cd and Tl by chelates reached equilibrium within 2 h, and the activation process showed three stages. Under neutral conditions, chelates had better activation performance on Pb- and Cd-contaminated soils. Except for S,S-ethylenediamine disuccinic acid (S,S-EDDS) and citric acid (CA), the maximum equilibrium activation effect (MEAE) of ethylenediaminetetraacetic acid (EDTA), N,N-bis (carboxymethyl) glutamic acid (GLDA), diethylenetriaminepentaacetic acid (DTPA) and aminotriacetic acid (NTA) was over 81%. The MEAE of Tl-contaminated soil was less than 15%. The decreasing order of the dosage of chelating agents corresponding to MEAE for three types of contaminated soils was Pb-, Cd- and Tl-contaminated soil, relating to the forms of heavy metals, the stability constants of metal-chelates and the activation of non-target elements Fe in red soil. Under acidic conditions, the activation efficiencies of chelates decreased to differing degrees in Pb- and Cd-contaminated soils, whereas the activation efficiencies of chelating agents in Tl-contaminated soils were slightly enhanced.


Assuntos
Cádmio/química , Quelantes/química , Chumbo/química , Poluentes do Solo/química , Tálio/química , Biodegradação Ambiental , Ácido Cítrico/química , Ácido Edético/química , Etilenodiaminas/química , Glutamatos/química , Glicina/análogos & derivados , Glicina/química , Ácido Pentético/química , Solo/química , Succinatos/química
5.
Mater Sci Eng C Mater Biol Appl ; 106: 110245, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753357

RESUMO

The recent discovery of small interfering RNAs (siRNAs) has opened new avenues for designing personalized treatment options for various diseases. However, the therapeutic application of siRNAs has been confronted with many challenges because of short half-life in circulation, poor membrane penetration, difficulty in escaping from endosomes, and insufficient release into the cytosol. To overcome these challenges, we designed a diethylenetriamine (DETA)- and tetraethylenepentamine (TEPA)-modified polyamidoamine dendrimer generation 4.5 (PDG4.5), and characterized it using 1H nuclear magnetic resonance (NMR), 13C NMR, correlation spectroscopy (COSY), heteronuclear single-quantum correlation spectroscopy (HSQC), and Fourier transform infrared (FTIR) spectroscopy followed by conjugation with siRNA. The PDG4.5-DETA and PDG4.5-TEPA polyplexes exhibited spherical nanosize, ideal zeta potential, and effective siRNA binding ability, protected the siRNA from nuclease attack, and revealed less cytotoxicity of PDG4.5-DETA and PDG4.5-TEPA in HeLa cells. More importantly, the polyplexes also revealed good cellular internalization and facilitated translocation of the siRNA into the cytosol. Thus, PDG4.5-DETA and PDG4.5-TEPA can act as potential siRNA carriers in future medical and pharmaceutical applications.


Assuntos
Dendrímeros/química , Etilenodiaminas/química , Nylons/química , Poliaminas/química , RNA Interferente Pequeno/química , Portadores de Fármacos/química , Células HeLa , Humanos , Espectroscopia de Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Anal Chim Acta ; 1096: 34-43, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31883589

RESUMO

A novel 3D paper-based microfluidic screen-printed electrode (SPE) composed of two layers was constructed by photolithography and screen-printing technology. Aldehyde functionalized hydrophilic zone of the counter and reference electrodes layer was prepared for glucose oxidase immobilization. Highly conductive prussian blue deposited reduced graphene oxide-tetraethylene pentamine (rGO-TEPA/PB) modified paper working electrode layer can be used as an electrochemical sensitive membrane for quantitative detection of hydrogen peroxide (H2O2), which was the enzyme-catalyzed reaction product. Therefore, this 3D paper-based microfluidic electrochemical biosensor can be used for quantitative detection of glucose. Under optimum conditions, the proposed biosensor can be used for quantitative determination of glucose over a wide linear range of 0.1 mM-25 mM with detection limit of 25 µM. Finally, the 3D paper-based microfluidic electrochemical biosensor was applied to determine glucose in human sweat and blood, and the obtained results were in good consistency with values measured by Roche's blood glucose meter. In addition, the proposed 3D paper-based electrochemical device showed good repeatability, stability, and anti-interference, which would be of great potential to monitor glucose in complex biological fluids.


Assuntos
Técnicas Biossensoriais/instrumentação , Glicemia/análise , Glucose/análise , Grafite/química , Técnicas Analíticas Microfluídicas/instrumentação , Suor/química , Técnicas Eletroquímicas/instrumentação , Enzimas Imobilizadas/química , Desenho de Equipamento , Etilenodiaminas/química , Glucose Oxidase/química , Humanos , Peróxido de Hidrogênio/análise , Limite de Detecção , Oxirredução , Papel , Impressão Tridimensional
7.
Ecotoxicol Environ Saf ; 187: 109821, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31677572

RESUMO

In this study, a porous framework MOF-74(Zn) (Zn2 (DHBDC)(DMF)(H2O)2, H4dondc = 1, 5-dioxido-2, 6-naphthalenedicarboxylic acid) with open metal sites was successful synthesized. MOF-74(Zn) as a template was grafted on the open metal sites with ethylenediamine (en) named MOF-74(Zn)-en to develop a highly selective and sensitive fluorescence detector for rapid determination of tetrabromobisphenol A (TBBPA). The obtained MOF-74(Zn)-en was well characterized by Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM) and showed ideal properties of photoluminescence. The fluorescence enhancement showed a good linear relationship with the concentrations of TBBPA in the range of 50-400 µg/L, and its limit of detection could reach to 0.75 µg/L. Furthermore, the possible sensing mechanism of the fluorescence enhancement could be attributed to Förster resonance energy transfer (FRET). The results will provide a convenient and quick method for detection of TBBPA. To the best of my knowledge, this is the first case to detect TBBPA by fluorescence enhancement with MOF derivatives.


Assuntos
Fluorescência , Estruturas Metalorgânicas/química , Bifenil Polibromatos/análise , Poluentes Químicos da Água/análise , Zinco/química , Etilenodiaminas/química , Limite de Detecção , Bifenil Polibromatos/química , Espectrometria de Fluorescência/instrumentação , Poluentes Químicos da Água/química
8.
Analyst ; 144(23): 7017-7023, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31647064

RESUMO

The rapid identification of human body fluids is meaningful for forensic casework. However, current methods suffer from several limitations such as poor sensitivity, time consumption and big sample consumption. Herein, we developed a mass spectrometry method to distinguish human body fluids (blood, semen, urine, sweat, and saliva) based on small molecular regions with no pretreatment, microliter sample consumption and high throughput. A highly sensitive and high salt-tolerance matrix N-(1-naphthyl)ethylenediamine dihydrochloride (NEDC) was used to efficiently detect metabolites in complex humoral environment. Some characteristic small metabolic molecules such as heme, hemin, creatinine, phosphate acid, uric acid, citric acid and lactic acid were identified and served as potential biomarkers to differentiate different body fluid types. Further principal component analysis (PCA) was performed to cluster the body fluid samples and three principal components allowed 75% clustering of all body fluid types. Blind testing revealed that nine out of ten unknown body fluid samples could be correctly classified into their corresponding group. This novel method can efficiently differentiate five body fluids with minimal interferences due to the storage time (less than 12 months) and carrier materials (cotton, fabric and tissue). The whole process from sampling to recording of mass spectra of body fluids can be finished in less than 10 minutes. We believe that this developed strategy has significant implications for rapid and effective human body fluid screening in forensic casework.


Assuntos
Análise Química do Sangue/métodos , Saliva/química , Sêmen/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Suor/química , Urina/química , Adolescente , Adulto , Biomarcadores/análise , Etilenodiaminas/química , Feminino , Ciências Forenses/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Adulto Jovem
9.
Mater Sci Eng C Mater Biol Appl ; 104: 110006, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499941

RESUMO

The present work shows the development and evaluation of the veterinary antibiotic cloxacillin benzathine (CLOXB) loaded into poly-ε-caprolactone (PCL) nanocapsules (NC), as a potential new treatment strategy to manage bovine intramammary infections, such as mastitis. Staphylococcus aureus-induced mastitis is often a recurrent disease due to the persistence of bacteria within infected cells. CLOXB-PCL NC were prepared by interfacial deposition of preformed biodegradable polymer followed by solvent displacement method. The mean diameter of NC varied from 241 to 428 nm and from 326 to 375 nm, when determined by dynamic light scattering and by atomic force microscopy, respectively. The zeta potential of NC was negative and varied from -28 to -51 mV. In vitro release studies from the NC were performed in two media under sink conditions: PBS with 1% polyethylene glycol or milk. A reversed-phase HPLC method was developed to determine the NC entrapment efficiency and kinetics of CLOXB release from the NC. Free CLOXB dissolution occurred very fast in both media, while drug release from the NC was slower and incomplete (below 50%) after 9 h. CLOXB release kinetics from polymeric NC was fitted with the Korsmeyer-Peppas model indicating that CLOXB release is governed by diffusion following Fick's law. The fluorescence confocal microscopy images of macrophage-like J774A.1 cells reveal NC uptake and internalization in vitro. In addition, antimicrobial effect of the intramammary administration of CLOXB-PCL NC in cows with mastitis resulted in no clinical signs of toxicity and allowed complete pathogen elimination after treatment. The in vivo results obtained in this work suggest that CLOXB-PCL NC could be a promising formulation for the treatment of intramammary infections in cattle, considering their physicochemical properties, release profiles and effects on bovine mastitis control.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Cloxacilina/análogos & derivados , Cloxacilina/química , Etilenodiaminas/química , Nanocápsulas/química , Polímeros/química , Animais , Caproatos/química , Bovinos , Linhagem Celular , Difusão , Feminino , Lactonas/química , Mastite Bovina , Camundongos , Leite/microbiologia , Polietilenoglicóis/química , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos
10.
Environ Sci Pollut Res Int ; 26(27): 28319-28327, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31372951

RESUMO

Biodegradable chelator-assisted phytoextraction is an effective method to enhance remediation efficiency of heavy metals. A greenhouse experiment was conducted to investigate the effects of S,S-ethylenediamine disuccinic acid (EDDS), citric acid (CA), and oxalic acid (OA) application before planting on the biomass and physiological characteristics of hyperaccumulator Sedum alfredii Hance, and its cadmium (Cd), lead (Pb), and zinc (Zn) uptake. The results showed that EDDS and CA slightly inhibited the plant growth, while the 1.0 mmol kg-1 (OA-1) and 2.5 mmol kg-1 OA (OA-2.5) addition produced 55.3% and 35.2% greater shoot biomass compared with the control, which may be related to that OA can produce higher leaf chlorophyll and soluble protein contents, as well as lower concentrations of malondialdehyde. At the same time, the concentrations of Pb and Zn in leaf after OA-2.5 treatment significantly increased by 127% and 28.4%, and the Cd, Pb, and Zn uptake by shoot was obviously enhanced by 21.5%, 117%, and 44.9% for OA-1 addition and by 39.1%, 80.0%, and 58.3% for OA-2.5 addition, respectively, in comparison with the control (P < 0.05). The reductions in available contents of Cd, Pb, and Zn in soil were observed after phytoextraction by Sedum alfredii Hance when OA was treated. These findings imply that OA was suitable for facilitating Sedum alfredii Hance to remove Cd, Pb, and Zn in co-contaminated soil.


Assuntos
Cádmio/metabolismo , Ácido Cítrico/metabolismo , Etilenodiaminas/química , Chumbo/metabolismo , Metais Pesados/análise , Sedum/metabolismo , Zinco/metabolismo , Biomassa , Cádmio/análise , Quelantes/metabolismo , Ácido Cítrico/química , Chumbo/análise , Metais Pesados/química , Solo , Zinco/análise
11.
Pharmacol Res Perspect ; 7(5): e00511, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31463067

RESUMO

Opioids are powerful analgesics acting via the human µ-opiate receptor (hMOR). Opioid use is associated with adverse effects such as tolerance, addiction, respiratory depression, and constipation. Two synthetic opioids, AH-7921 and U-47700 that were developed in the 1970s but never marketed, have recently appeared on the illegal drug market and in forensic toxicology reports. These agents were initially characterized for their analgesic activity in rodents; however, their pharmacology at hMOR has not been delineated. Thus, we synthesized over 50 chemical analogs based on core AH-7921 and U-47700 structures to assess for their ability to couple to Gαi signaling and induce hMOR internalization. For both the AH-7921 and U-47700 analogs, the 3,4-dichlorobenzoyl substituents were the most potent with comparable EC50 values for inhibition of cAMP accumulation; 26.49 ± 11.2 nmol L-1 and 8.8 ± 4.9 nmol L-1, respectively. Despite similar potencies for Gαi coupling, these two compounds had strikingly different hMOR internalization efficacies: U-47700 (10 µmol L-1) induced ~25% hMOR internalization similar to DAMGO while AH-7921 (10 µmol L-1) induced ~5% hMOR internalization similar to morphine. In addition, the R, R enantiomer of U-47700 is significantly more potent than the S, S enantiomer at hMOR. In conclusion, these data suggest that U-47700 and AH-7921 analogs have high analgesic potential in humans, but with divergent receptor internalization profiles, suggesting that they may exhibit differences in clinical utility or abuse potential.


Assuntos
Analgésicos Opioides/síntese química , Etilenodiaminas/síntese química , Receptores Opioides mu/metabolismo , Analgésicos Opioides/química , Analgésicos Opioides/farmacologia , Linhagem Celular , AMP Cíclico/metabolismo , Etilenodiaminas/química , Etilenodiaminas/farmacologia , Humanos , Estrutura Molecular , Receptores Opioides mu/química
12.
Molecules ; 24(13)2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31324053

RESUMO

The zinc(II) ion forms stable complexes with a wide variety of ligands, but those related to Schiff-bases are among the most largely investigated. This review deals with the peculiar aggregation characteristics of Zn(II) Schiff-base complexes from tetradentate N2O2 salen-type ligands, L, derivatives from salicylaldehydes and 1,2-diamines, and is mostly focused on their spectroscopic properties in solution. Thanks to their Lewis acidic character, ZnL complexes show interesting structural, nanostructural, and aggregation/deaggregation properties in relation to the absence/presence of a Lewis base. Deaggregation of these complexes is accompanied by relevant changes of their spectroscopic properties that can appropriately be exploited for sensing Lewis bases. Thus, ZnL complexes have been investigated as chromogenic and fluorogenic chemosensors of charged and neutral Lewis bases, including cell imaging, and have shown to be selective and sensitive to the Lewis basicity of the involved species. From these studies emerges that these popular, Lewis acidic bis(salicylaldiminato)Zn(II) Schiff-base complexes represent classical coordination compounds for modern applications.


Assuntos
Complexos de Coordenação/química , Etilenodiaminas/química , Bases de Schiff/química , Zinco/química , Ácidos de Lewis , Ligantes , Modelos Moleculares , Soluções , Análise Espectral , Relação Estrutura-Atividade
13.
Talanta ; 204: 592-601, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357339

RESUMO

Development of conjugated polymers with fluorescence sensing characteristics has received close attention from researchers in fields of environmental protection, biosensing and toxins detection on food. In this paper, novel polyaniline derivatives of poly(9-methyl-9H-carbazol-3-amine) and poly(9,9-dihexyl-9H-fluoren-2-amine) are prepared by facile chemical polymerization. Then they are characterized with NMR (Nuclear Magnetic Resonance), GPC (Gel Permeation Chromatography), XRD (X-Ray Diffraction), FT-IR (Fourier Transform Infrared spectroscopy), FL (Fluorescence spectrometry) and UV-vis (Ultraviolet-visible spectroscopy) characterizations and further applied to the fluorescence detection of different acids and amines. Moreover, the obtained poly(9-methyl-9H-carbazol-3-amine) displays excellent fluorescence properties in the detection for both acids and amines. Besides, this poly(9-methyl-9H-carbazol-3-amine) can not only be used for fluorescence detection in solution, but also can be prepared into solid state and applied in the gas phase fluorescence detection. This work has greatly expanded the scope of application to these polyaniline derivatives materials, opening a new path for the researches on multi-functional chemosensor.


Assuntos
Compostos de Anilina/química , Carbazóis/química , Fluorenos/química , Corantes Fluorescentes/química , Compostos de Anilina/síntese química , Carbazóis/síntese química , Etilenodiaminas/análise , Etilenodiaminas/química , Fluorenos/síntese química , Fluorescência , Corantes Fluorescentes/síntese química , Ácido Clorídrico/análise , Ácido Clorídrico/química , Ligação de Hidrogênio , Limite de Detecção , Metilaminas/análise , Metilaminas/química , Ácido Nítrico/análise , Ácido Nítrico/química , Reprodutibilidade dos Testes , Espectrometria de Fluorescência/métodos
14.
Chem Commun (Camb) ; 55(65): 9681-9684, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31347618

RESUMO

Here, we report a convenient, fast labeling strategy for the imaging of cell surface sialic acids (SAs, nine-carbon monosaccharides located at the terminals of cell surface sugar chains). This strategy is based on the synthesis of sticky, furry and fluorescent "wool-balls", which are wound into nanoclusters from p-benzoquinone/ethylenediamine polymer "wires". With abundant amino groups at the surface, the wool-balls can easily stick to the C-7 aldehyde group generated at the ends of periodate treated SAs in less than 30 min.


Assuntos
Benzoquinonas/química , Etilenodiaminas/química , Corantes Fluorescentes/química , Nanopartículas/química , Polímeros/química , Ácidos Siálicos/análise , Animais , Benzoquinonas/síntese química , Linhagem Celular Tumoral , Etilenodiaminas/síntese química , Fluorescência , Humanos , Camundongos , Microscopia de Fluorescência/métodos , Neuraminidase/química , Tamanho da Partícula , Polímeros/síntese química , Células RAW 264.7 , Bases de Schiff/síntese química , Bases de Schiff/química , Ácidos Siálicos/química
15.
Int J Biol Macromol ; 136: 1209-1218, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31252016

RESUMO

In the present research, a biopolymer Chitosan (C) grafted with ethylenediamine (EDA) and methyl acrylate (MA) were compared for the adsorption of Congo red dye from aqueous phase. The grafted chitosan product was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and point of zero charge to study the change in mechanical and thermal properties. The effects of process variables like adsorbent loading, initial dye concentration, initial solution pH, contact time and temperature on adsorption phenomena were investigated. The equilibrium isotherm data was analyzed using Langmuir and Freundlich isotherm models, and the adsorption followed the Langmuir isotherm model (R2 = 0.992 and 0.991 for EDAC and MAC, respectively). The maximum adsorption capacity of EDAC and MAC for Congo red uptake calculated from Langmuir isotherm model was 1607 mg/g and 1143 mg/g, respectively. The adsorption kinetics was studied using pseudo 1st and 2nd order models. Pseudo second order rate model provided the best fit for both grafted adsorbents with R2 ≥0.99. The values of Gibbs free energy (-9.628 and -8.878 kJ/mol), enthalpy (44.9 and 42.2 kJ/mol) and entropy (0.18 and 0.17 J/mol·K) revealed spontaneous and endothermic adsorption of Congo red onto EDAC and MAC surface. The pollutant adsorption test indicated that chitosan grafting with ethylenediamine is superior to Methyl acrylate grafting agent.


Assuntos
Quitosana/química , Corantes/química , Corantes/isolamento & purificação , Vermelho Congo/química , Vermelho Congo/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação , Acrilatos/química , Adsorção , Etilenodiaminas/química , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica , Água/química , Purificação da Água
16.
Food Chem ; 297: 124974, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253270

RESUMO

In this study, through in-situ polymerization process, a novel composite of attapulgite/hydrophilic molecularly imprinted monolithic resin (AT/HMIMR) were prepared in pipette tips for extraction trace plant growth regulators in cucumbers. In the preparation procedure, fibrillar attapulgite nanoparticles were embedded to increase extraction capacity, polyethyleneglycol-6000 was employed as a dual-function porogen, that acted as both the structure-directing agent of the HMIMR and the attapulgite dispersant. N-(1-naphthyl) ethylenediamine dihydrochloride was used as a dummy template to accurate quantification on extraction procedures. Experimental parameters of AT/HMIMR for extracting plant growth regulators from cucumbers were optimized, and the results showed that the recoveries of ranged from 92.4% to 101.1% with relative standard deviations ≤ 6.5% (n = 3). Considering its microporous monolithic column structure, multiple adsorption mechanism, and specific selectivity, AT/HMIMR shows promise for applications that require specific recognition for the analytes in real complex samples.


Assuntos
Cucumis sativus/metabolismo , Compostos de Magnésio/química , Impressão Molecular , Reguladores de Crescimento de Planta/isolamento & purificação , Resinas Sintéticas/síntese química , Compostos de Silício/química , Adsorção , Cromatografia Líquida de Alta Pressão , Etilenodiaminas/química , Interações Hidrofóbicas e Hidrofílicas , Polietilenoglicóis/química , Polimerização , Extração em Fase Sólida
17.
Molecules ; 24(11)2019 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-31181723

RESUMO

We report on new Zn-Salen oligomer receptors able to recognize a nerve agent simulant, namely dimethyl methylphosphonate (DMMP), by a supramolecular approach. In particular, three Zn-Salen oligomers (Zn-Oligo-A, -B, and -C), differing by the length distribution, were obtained and characterized by NMR, Gel Permeation Chromatography (GPC), UV-Vis, and fluorescence spectroscopy. Furthermore, we investigated their recognition properties towards DMMP by using fluorescence measurements. We found that the recognition ability depends on the length of the oligomeric chain, and the Zn-Oligo-C shows a binding constant value higher than those already reported in literature for the DMMP detection.


Assuntos
Etilenodiaminas/química , Agentes Neurotóxicos/análise , Compostos Organofosforados/análise , Zinco/química , Adsorção , Fluorescência , Cinética , Ligantes , Compostos Organofosforados/química , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Fluorescência
18.
PLoS One ; 14(5): e0216230, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31150413

RESUMO

Organelle selective imaging can reveal structural and functional characters of cells undergoing external stimuli, and is considered critical in revealing biological fundamentals, designing targeted delivery system, and screening potential drugs and therapeutics. This paper describes the nucleoli targeting ability of nanoscale carbon dots (including nanodiamond) that are hydrothermally made with controlled surface charges. The surface charges of carbon dots are controlled in the range of -17.9 to -2.84 mV by changing the molar ratio of two precursors, citric acid (CA) and ethylenediamine (EDA). All carbon dots samples show strong fluorescence under wide excitation wavelength, and samples with both negative and positve charges show strong fluorescent contrast from stained nucleoli. The nucleoli selective imaging of live cell has been confirmed with Hoechst staining and nucleoli specific staining (SYTO RNA-select green), and is explained as surface charge heterogeneity on carbon dots. Carbon dots with both negative and positive charges have better ability to penetrate cell and nucleus membranes, and the charge heterogeneity helps carbon dots to bind preferentially to nucleoli, where the electrostatic environment is favored.


Assuntos
Carbono , Nucléolo Celular/metabolismo , Pontos Quânticos/química , Ácido Cítrico/química , Ácido Cítrico/metabolismo , Etilenodiaminas/química , Etilenodiaminas/metabolismo , Fluorescência , Imagem Óptica/métodos , Pontos Quânticos/metabolismo , Coloração e Rotulagem , Eletricidade Estática , Propriedades de Superfície
19.
Biomolecules ; 9(5)2019 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-31109093

RESUMO

The aminoethyl-chitooligosaccharide (AE-COS) was reported to inhibit human gastric cancer cell proliferation and human fibrosarcoma cell invasion. In this study, the role of AE-COS in down-regulation of proliferation of human lung A549 cancer cells was evaluated. It was found that AE-COS was able to reduce A549 cell proliferation to (32 ± 1.3)% at a concentration of 500 µg/ml. Moreover, AE-COS treatment caused suppression on COX-2 expression in a dose-dependent manner. Notably, the role of AE-COS in induction of cell apoptosis was observed via decreasing Bcl-2 expression and increasing caspase-3 and -9 activation. Accordingly, the antiproliferative effect of AE-COS was indicated due to suppression of cell proliferation and induction of cell apoptosis, suggesting AE-COS as a promising chemotherapy agent for treatment of lung cancer.


Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Quitina/análogos & derivados , Etilenodiaminas/química , Antineoplásicos/química , Apoptose , Linhagem Celular Tumoral , Quitina/química , Humanos
20.
Molecules ; 24(9)2019 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-31052604

RESUMO

Salen ligands are a class of Schiff bases simply obtained through condensation of two molecules of a hydroxyl-substituted aryl aldehyde with an achiral or chiral diamine. The prototype salen, or N,N'-bis(salicylidene)ethylenediamine has a long history, as it was first reported in 1889, and immediately, some of its metal complexes were also described. Now, the salen ligands are a class of N,N,O,O tetradentate Schiff bases capable of coordinating many metal ions. The geometry and the stereogenic group inserted in the diamine backbone or aryl aldehyde backbone have been utilized in the past to efficiently transmit chiral information in a variety of different reactions. In this review we will summarize the important and recent achievements obtained in stereocontrolled reactions in which Al(salen) metal complexes are employed. Several other reviews devoted to the general applications and synthesis of chromium and other metal salens have already been published.


Assuntos
Etilenodiaminas/química , Compostos Organometálicos/química , Catálise , Técnicas de Química Sintética , Reação de Cicloadição , Etilenodiaminas/síntese química , Estrutura Molecular , Compostos Organometálicos/síntese química , Polimerização , Estereoisomerismo , Uridina Difosfato N-Acetilglicosamina/análogos & derivados
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