Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 130
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Inorg Chem ; 59(2): 1323-1331, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31920084

RESUMO

We first design and synthesize a dendritic aromatic 6-carboxyl linker (H6TDCPB), which is successfully assembled with Cd(II) ion to construct a porous metal-organic framework with a raw Cd6 cluster, {[Cd3(TDCPB)·2DMAc]·DMAc·4H2O}n (namely, complex 1). More interestingly, six adjacent linkers are packed together by π-π-stacking interactions to form an amazing six-molecule accumulation in the crystal structure. By virtue of high stability and luminescent properties, the as-synthesized sample not merely owns an excellent detectable ability but also possesses an outstanding selectivity for nitrofurans with remarkable recursitivity.


Assuntos
Antibacterianos/análise , Corantes Fluorescentes/química , Medições Luminescentes , Estruturas Metalorgânicas/química , Corantes Fluorescentes/síntese química , Estruturas Metalorgânicas/síntese química , Estrutura Molecular
2.
Chem Commun (Camb) ; 56(16): 2431-2434, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-31995041

RESUMO

A composite nanosensor based on Zr(iv)-MOFs and PNPP was developed, and was successfully applied for the in situ fluorescence imaging of phosphate and ALP levels in mice with parathyroid dysfunction. The current work provides new ideas for further development of the diagnosis of parathyroid diseases.


Assuntos
Fosfatase Alcalina/análise , Corantes Fluorescentes/química , Estruturas Metalorgânicas/química , Nanopartículas/química , Doenças das Paratireoides/diagnóstico por imagem , Fosfatos/análise , Zircônio/química , Fosfatase Alcalina/metabolismo , Animais , Modelos Animais de Doenças , Corantes Fluorescentes/síntese química , Estruturas Metalorgânicas/síntese química , Camundongos , Doenças das Paratireoides/metabolismo
3.
Chem Commun (Camb) ; 56(4): 519-522, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31825411

RESUMO

For the first time, a facile solvothermal method to synthesize covalent organic frameworks (COFs) with a nanosized structure and bright fluorescence was reported to monitor drug loading with the naked eye and realize responsive release.


Assuntos
Antibióticos Antineoplásicos/química , Doxorrubicina/química , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Corantes Fluorescentes/química , Estruturas Metalorgânicas/química , Corantes Fluorescentes/síntese química , Estruturas Metalorgânicas/síntese química , Estrutura Molecular , Tamanho da Partícula
5.
Talanta ; 206: 120194, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514904

RESUMO

Phthalate esters (PAEs), a category of widely used plasticizers, are tend to migrate from plastic packaging to drinks. In this paper, we develop a simple and rapid coprecipitation method for synthesis of a magnetic covalent organic framework (COF) adsorbent. The fabricated COF-(TpBD)/Fe3O4 was applied to magnetic solid phase extraction (MSPE) of 15 phthalate esters (PAEs) for subsequent GC-MS/MS determination in beverage samples. The as-synthesized magnetic adsorbent exhibited great potential in PAEs analysis with a limit of detection of 15 PAEs ranged from 0.005 to 2.748 µg L-1 (S/N = 3). The intra-day and inter-day relative standard deviations (RSD) value of the PAEs were less than 8.8% and 9.9%, respectively. The adsorbent can be reused after washing with methanol. The developed method was successfully applied for the determination of trace PAEs in eight beverages with recoveries ranging from 79.3% to 121.8% and RSDs were less than 11.9%. This work provides a simple magnetization process, which facilitates the application of COFs for enrichment and separation of PAEs in beverages with different matrices.


Assuntos
Bebidas/análise , Ésteres/análise , Óxido Ferroso-Férrico/química , Contaminação de Alimentos/análise , Estruturas Metalorgânicas/química , Ácidos Ftálicos/análise , Adsorção , Óxido Ferroso-Férrico/síntese química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Limite de Detecção , Fenômenos Magnéticos , Estruturas Metalorgânicas/síntese química , Plastificantes/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
6.
Mini Rev Med Chem ; 19(20): 1644-1665, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31880236

RESUMO

Metal-Organic Frameworks (MOFs) have aroused great interest in the field of nanoscience and nanotechnology particularly in biomedical domains, such as Drug Delivery System (DDS), Biomedical Imaging (BI) and Photodynamic Therapy (PDT). As an emerging material, MOFs possess extraordinarily high surface area, controllable particle size and good biocompatibility. With extraordinary flexibility in the selection of organic and inorganic components, MOFs can rationally be tuned to obtain the materials having versatile structures and porosities. MOFs can serve as ideal vehicles for DDS, BI and PDT through modification and function. In this review, we summarized the design and synthetic strategies for preparing MOFs and introduced their recent advanced usage in DDS, BI and PDT. Finally, the prospect and future challenges of these nanomaterials are also documented.


Assuntos
Sistemas de Liberação de Medicamentos , Desenho de Drogas , Estruturas Metalorgânicas/síntese química , Animais , Tecnologia Biomédica , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Humanos , Concentração de Íons de Hidrogênio , Estruturas Metalorgânicas/química , Fotoquimioterapia
7.
Chem Commun (Camb) ; 55(93): 13967-13970, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31690896

RESUMO

A rational strategy was introduced for the synthesis of a novel dual functionalized metal-organic framework nanocomposite (AuGC/ZIF-8) with ultra-hydrophilicity to enhance glycopeptide enrichment. The advantages of ingenious synergy, low-cost, facile and large-scale synthesis, and excellent enrichment performance will enable it to have a bright future in nanomaterial synthesis, glycoproteomics analysis, and related biochemistry.


Assuntos
Glicopeptídeos/química , Estruturas Metalorgânicas/síntese química , Nanocompostos/química , Interações Hidrofóbicas e Hidrofílicas , Estruturas Metalorgânicas/química , Tamanho da Partícula , Propriedades de Superfície
8.
Top Curr Chem (Cham) ; 377(6): 32, 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31654264

RESUMO

Metal-organic frameworks (MOFs) are an emerging class of porous crystalline materials attracting attention for their vast array of topologies as well as potential applications in gas storage, heterogeneous catalysis, and molecular sensing. In most cases, organocarboxylates (or corresponding carboxylic acids) are the most common building block, achieving well-defined metal-carboxylate coordination motifs in MOF structures. However, organosulfonates (or corresponding sulfonic acids) have been less well studied in MOF chemistry, probably owing to the weak coordination tendency of the sulfonate oxygens toward metal centers. This review summarizes the research on organosulfonate-based porous crystalline MOFs in recent years. The construction of most porous organosulfonate MOFs relies on using either a second N-donor ligand or carboxylate-sulfonate bifunctional ligands. Despite occupying more confined porosity than the carboxylate counterpart, the permanent porosity in organosulfonate MOFs is often highly polar and hydrophilic. Thus, organosulfonate MOFs often exhibit improved proton/Li+ conductivity as well as CO2 affinity compared with their carboxylate-based counterparts. In addition, the application of organosulfonate MOFs in molecular sensing, molecular sieving, catalysis, and anion exchange are discussed in this review as well.


Assuntos
Estruturas Metalorgânicas/química , Ácidos Sulfônicos/química , Dióxido de Carbono/química , Ácidos Carboxílicos/química , Catálise , Estruturas Metalorgânicas/síntese química , Porosidade
9.
Anal Chim Acta ; 1089: 66-77, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31627820

RESUMO

The dehydration reaction of tetraamino porphyrin and 4,4'-biphenyldicarboxaldehyde was performed for the synthesis of a novel covalent organic framework (COF), which was decorated on magnetic Fe3O4 to obtain core-shell structured Fe3O4@COFs nanospheres for the first time, for effective extraction and enrichment of sulfonamides (SAs). The morphology and structure of the synthesized nanospheres were characterized through various methods. The extraction conditions for six SAs including sulfadiazine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, sulfadimethoxine were systematically optimized. Fe3O4@COFs nanospheres were evaluated for magnetic solid-phase extraction. By coupling with high-performance liquid chromatography, a facile and sensitive method was established for the quantitation analysis of six SAs. The method showed good linearity ranging from 1 to 500 ng mL-1 with R2 > 0.99, high sensitivity with LODs in the range of 0.2-1 ng mL-1, and high precision with RSDs≤6.3%. This method was further applied into determination of SAs in environmental water and food samples, with recoveries in the range of 65.3%-107.3% and RSDs≤6.7%. These successful applications suggest that the core-shell structured Fe3O4@COFs nanospheres could be used as a potential adsorbent for efficient extraction and analysis of trace SAs.


Assuntos
Contaminação de Alimentos/análise , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Porfirinas/química , Sulfonamidas/análise , Poluentes Químicos da Água/análise , Adsorção , Animais , Galinhas , Lagos/análise , Limite de Detecção , Estruturas Metalorgânicas/síntese química , Leite/química , Penaeidae , Porfirinas/síntese química , Frutos do Mar/análise , Extração em Fase Sólida/métodos
10.
ACS Appl Mater Interfaces ; 11(40): 36782-36788, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31532179

RESUMO

Combining biocatalytic and chemocatalytic reactions in a one-pot reaction not only avoids the tedious isolation of intermediates during the reactions but also provides a desirable alternative to extend the range of catalytic reactions. Here, we report a facile strategy to immobilize an enzyme, glucose oxidase (GOx), on PCN-222(Fe) induced by electrostatic interaction in which PCN-222(Fe) serves as both a support and chemocatalyst. The immobilization was confirmed through ζ potential measurement, confocal laser scanning microscopy, Fourier transform infrared spectrometry, and UV-vis spectroscopy. This chemo-biocatalyst was applied to a cascade reaction to catalyze glucose oxidation and ABTS (ABTS = 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (or pyrogallol) oxidation. The catalytic kinetics studies show that these chemo-biocatalytic cascade reactions obey the Michaelis-Menten equation, which indicates that the cascade reactions follow the typical enzymatic dynamic regulation process. Interestingly, GOx/PCN-222(Fe) exhibits an exceptional acid-stable catalytic performance as evidenced by circular dichroism spectroscopy where no significant structure change was observed toward acidic solutions with different pH values. GOx/PCN-222(Fe) also displays desirable recyclability since no significant loss of conversion rates was found after six repeated reactions. This work presents a convenient strategy to construct metal-organic framework based chemo-biocatalysts, which may find potential applications in sensing and nanomachines.


Assuntos
Biocatálise , Glucose Oxidase/metabolismo , Estruturas Metalorgânicas/química , Eletricidade Estática , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo , Glucose/metabolismo , Glucose Oxidase/ultraestrutura , Estruturas Metalorgânicas/síntese química , Oxirredução
11.
Analyst ; 144(21): 6254-6261, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31560359

RESUMO

As VEGF mRNA is an endothelial cell-specific mitogen and a key regulator of angiogenesis in a variety of physiological and pathological processes, high expression levels of VEGF messenger RNA (mRNA) contribute to VEGF-driven angiogenesis in the hypoxic areas of solid tumors and then disrupt the vascular barrier, which may potentiate tumor cell extravasation. Thus, monitoring the changes in VEGF mRNA is necessary to understand the genetic programme under hypoxic conditions and thus facilitate risk assessment and risk reduction in hypoxic environments. Herein, a new fluorescent nanoprobe based on azoreductase-responsive functional metal-organic frameworks (AMOFs) was developed to realize the imaging of VEGF mRNA under hypoxic conditions. Since the azobenzene units in the AMOFs can be reduced to amines by the highly expressed azoreductase in an oxygen-deficient environment, the VEGF mRNA-targeted molecular beacon (MB), which is adsorbed on the surface of AMOFs via electrostatic interactions, can be released due to the structural damage of AMOFs. Moreover, TAMRA (carboxytetramethylrhodamine, donor) and Cy5 (acceptor) were close to each other due to the stem-loop conformation of MB, thus inducing high fluorescence energy resonance transfer (FRET) efficiency. Upon the addition of VEGF mRNA, the hybridization of VEGF mRNA destroyed the stem-loop conformation of MB, and then, the two fluorophores labeled on MB were separated with low FRET efficiency. This constructed fluorescent nanoprobe enables the quantitative analysis and in situ imaging of the VEGF mRNA level in living cells under hypoxic conditions. We expect that it will offer a potentially rich opportunity to understand the physiological processes of genetic programme.


Assuntos
Hipóxia Celular/fisiologia , Corantes Fluorescentes/química , Estruturas Metalorgânicas/química , NADH NADPH Oxirredutases/química , RNA Mensageiro/análise , Fator A de Crescimento do Endotélio Vascular/genética , Carbocianinas/química , Peptídeos Penetradores de Células/síntese química , Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/toxicidade , DNA/química , DNA/genética , Sondas de DNA/química , Sondas de DNA/genética , Transferência Ressonante de Energia de Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Estruturas Metalorgânicas/síntese química , Estruturas Metalorgânicas/toxicidade , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Hibridização de Ácido Nucleico , RNA Mensageiro/genética , Rodaminas/química
12.
Mater Sci Eng C Mater Biol Appl ; 105: 110111, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546392

RESUMO

Multiple drug resistant (MDR) has become a major issue in developing countries. MDR bacterial infections lead to significant increase in morbidity, mortality and cost of prolonged treatments. Therefore, designing of strategies for improving the antimicrobial potential of the therapeutic agents are highly required. Metal organic frameworks (MOFs) are highly tunable hybrid material, consist of metal ions linked together by organic bridging ligands have been used as an efficient drug delivery carrier because of their biodegradability, low toxicity and structure integrity upon loading and functionalizing process. Current study was based on the synthesis of chitosan coated MOFs with enhanced contact with S. aureus cell surface. Chitosan is deacetylated derivative of chitin and capable for non-bonding interaction with negatively charged bacterial cell leading to enhanced contact of MOFs with S. aureus. Chitosan coated MOFs were characterized with various techniques such as atomic force microscopy, scanning electron microscopy, DLS, FT-IR, TGA, DSC and Powder X-ray diffraction. They were also studied for their efficacy on resistant S. aureus, results revealed that Vancomycin bactericidal activity significantly increased upon loading in chitosan coated MOFs and caused increased inhibition of resistant S. aureus. AFM analysis of S. aureus strains clearly revealed complete distortion of morphology by treating with chitosan modified drug loaded MOFs. Findings of the current study suggest the potential of chitosan coated MOFs for reversing bacterial resistance against Vancomycin and provide new perspectives for improved antibiotic therapy of infections associated with MDR.


Assuntos
Antibacterianos/farmacologia , Quitosana/síntese química , Materiais Revestidos Biocompatíveis/síntese química , Farmacorresistência Bacteriana/efeitos dos fármacos , Estruturas Metalorgânicas/síntese química , Staphylococcus aureus/efeitos dos fármacos , Vancomicina/farmacologia , Varredura Diferencial de Calorimetria , Concentração Inibidora 50 , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Propriedades de Superfície , Termogravimetria , Difração de Raios X
13.
Analyst ; 144(19): 5875-5881, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31486467

RESUMO

A unique metal-organic framework with the formula [Cd4(H2L)2(L)·H2O]·3H2O (H4L = 5,5'-(1H-1,2,4-triazole-3,5-diyl)diisophthalic acid) was successfully constructed under solvothermal conditions. The frameworks with multiple free Lewis base sites and Lewis acid sites exhibited easily sensitized properties. After the encapsulation of Tb3+ cations, the as-synthesized Tb3+@Cd-MOF demonstrated strong luminescence induced by the efficient energy transfer from the bridging ligands to the Tb3+ cations, with the potential to serve as a chemical sensor. Interestingly, Tb3+@Cd-MOF was proven to be a very promising and highly selective and sensitive luminescent platform for the quantitative detection of arginine, which is the biomarker of cystinuria. The fluorescent probe presented high selectivity to arginine in urine with strong luminescence quenching. Furthermore, a convenient fluorescence-based test paper for the visual detection of arginine in applications was prepared. For the first time, arginine was quantified and monitored in urine by a highly efficient recyclable fluorescent sensor based on Tb3+-functionalized MOF hybrids, which may be a potential candidate for the further development of clinical diagnostic tools.


Assuntos
Arginina/urina , Corantes Fluorescentes/química , Estruturas Metalorgânicas/química , Térbio/química , Biomarcadores/urina , Cistinúria/diagnóstico , Fluorescência , Corantes Fluorescentes/síntese química , Humanos , Limite de Detecção , Estruturas Metalorgânicas/síntese química , Espectrometria de Fluorescência/métodos
14.
Anal Chim Acta ; 1079: 164-170, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31387707

RESUMO

Ultrathin two-dimensional (2D) metal-organic framework (MOF) nanosheets have attracted numerous attention due to their unparalleled advantages such as unique structures, large surface areas, good stability and high catalytic efficiency. In this paper, 2D Cu(bpy)2(OTf)2 nanosheets (Cu-MOF, bpy = 4,4-bipyridine, OTf = trifluoromethanesulfonate) are first utilized to achieve the fluorescent detection for H2O2 and glucose with their intrinsic peroxidase-like activity. The fluorescent biosensor Cu-MOF nanosheets were achieved by the efficient catalysis of non-fluorescent thiamine (TH) to strong fluorescent thiochrome in the presence of H2O2. With the combination of glucose oxidase, highly selective and sensitive fluorescent detection for glucose could be established with a detection limit of 0.41 µM and two separate linear ranges of 10-100 µM and 100-1000 µM, respectively. Furthermore, the developed method has been applied to human serum for the quantitative determination of glucose as a clinical diagnosis indicator of diabetes mellitus.


Assuntos
Materiais Biomiméticos/química , Glicemia/análise , Peróxido de Hidrogênio/análise , Estruturas Metalorgânicas/química , Aspergillus niger/enzimologia , Materiais Biomiméticos/síntese química , Técnicas Biossensoriais/métodos , Cobre/química , Fluorescência , Glucose Oxidase/química , Peroxidase do Rábano Silvestre/química , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , Estruturas Metalorgânicas/síntese química , Espectrometria de Fluorescência/métodos , Tiamina/análogos & derivados , Tiamina/química
15.
Dalton Trans ; 48(33): 12615-12621, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31378802

RESUMO

Here, we demonstrated the synthesis, characterization and application of a phthalimide-functionalized UiO-66 metal-organic framework, which showed an intrinsic detection capability for hydrazine. The MOF material (1) was solvothermally prepared by the reaction between ZrCl4 and 2-(1,3-dioxoisoindolin-2-yl)benzene-1,4-dioic acid (H2L) ligand in DMF solvent in the presence of benzoic acid for 48 h at 120 °C. The guest molecule free material (1') was used as a turn-on fluorescent sensor for the selective detection of hydrazine under biological conditions. The phthalimide group anchored in the structure of 1' is converted to the amine group by reaction with hydrazine and this free amine is accountable for the turn-on fluorescence behavior. The probe exhibited an extraordinary detection limit towards hydrazine (0.87 µM). The cellular imaging ability of the MOF probe for hydrazine was also demonstrated with MDAMB-231 breast cancer cells. The probe-loaded cells didn't show considerable cellular cytotoxicity and morphological deformities. They responded towards hydrazine solution by giving an intense blue fluorescent signal. Hence, 1' is capable of monitoring hydrazine in both the aqueous phase and living cells.


Assuntos
Corantes Fluorescentes/análise , Hidrazinas/análise , Estruturas Metalorgânicas/química , Imagem Óptica , Ftalimidas/química , Linhagem Celular Tumoral , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Estruturas Metalorgânicas/síntese química , Conformação Molecular , Espectrometria de Fluorescência
16.
Analyst ; 144(18): 5455-5461, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31432811

RESUMO

Over the past few years, artificial enzymes have attracted enormous attention due to their high stabilities and cost-effective productions. In this work, metal-organic framework-derived SiW12@Co3O4 was synthesized in large quantities by stirring the mixture at ambient temperature and calcination. The obtained SiW12@Co3O4 exhibited a highly inherent peroxidase-like activity and excellent stability. Kinetic studies demonstrated that the synthesized SiW12@Co3O4 had a strong binding affinity to 3,3',5,5'-tetramethylbenzidine (TMB), stronger than HRP had. Specifically, the peroxidase-like activity of SiW12@Co3O4 in an aqueous solution was well maintained after incubation at an elevated temperature, at an extreme pH and for a long time. A SiW12@Co3O4-based method was further developed for H2O2 and one-pot glucose detection with good sensitivity and reliability. The facile synthesis approach is expected to facilitate the practical use of metal-organic frameworks and their derivatives as enzyme mimics in the future.


Assuntos
Glucose/análise , Peróxido de Hidrogênio/análise , Estruturas Metalorgânicas/química , Benzidinas/química , Colorimetria/métodos , Glucose/química , Glucose Oxidase/química , Peróxido de Hidrogênio/química , Limite de Detecção , Estruturas Metalorgânicas/síntese química , Oxirredução , Peroxidase/química
17.
Inorg Chem ; 58(17): 11382-11388, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31402664

RESUMO

Enzyme-like metal-organic frameworks (MOFs) are currently one type of starring material in the fields of artificial enzymes and analytical sensing. However, there has been little progress in making use of the MOF structures based on the catalytically active metal center with multiple valences. Herein, we report a mixed-valence Ce-MOF (Ce-BPyDC) that can exhibit both oxidase-like and peroxidase-like activities. Ce-BPyDC was synthesized by a facile hydrothermal method, which preserves the rare coexistence of Ce(III) and Ce(IV) in the MOF structure. The enzymatic studies demonstrated the enzyme-like activities of Ce-BPyDC follow the Michaelis-Menten kinetics and are strongly dependent on temperature, pH, and reaction time. Ce-BPyDC was also revealed to exert high catalytic activity that could transcend horseradish peroxidase and other MOF nanozymes, due to the redox-active Ce(III)/Ce(IV) cycles inside. Furthermore, the simple synthesis, high nanozyme activity, and great stability of Ce-BPyDC motivated us to establish a colorimetric biosensing platform using 3,3',5,5'-tetramethylbenzidine as a color reagent. Adopting this strategy, we established a visual, sensitive, and selective colorimetric method for ascorbic acid (AA) detection, for which the linear interval and limit of detection were 1-20 and 0.28 µM, respectively. The successful AA detection in real juice samples implies the promising use of such mixed-valence MOF nanozymes in food and biomedical samples.


Assuntos
Técnicas Biossensoriais , Cério/química , Colorimetria , Estruturas Metalorgânicas/química , Ácido Ascórbico/análise , Catálise , Concentração de Íons de Hidrogênio , Estruturas Metalorgânicas/síntese química , Temperatura Ambiente
18.
Inorg Chem ; 58(15): 9773-9784, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31318533

RESUMO

In recent years, transition metal complexes have been developed for catalytical degradation of a phosphate ester bond, particularly in RNA and DNA; however, less consideration has been given for development of complexes for the degradation of a phosphorothioate bond, as they are the foremost used pesticides in the environment and are toxic to human beings. In this context, we have developed copper complexes of benzimidazolium based ligands for catalytical degradation of a series of organophosphates (parathion, paraoxon, methyl-parathion) at ambient conditions. The copper complexes (assigned as N1-N3) were characterized using single X-ray crystallography which revealed that all three complexes are mononuclear and distorted square planner in geometry. Further, the solution state studies of the prepared complexes were carried out using UV-visible absorption, fluorescence spectroscopy, and cyclic voltametry. The complexes N1 and N2 have benzimidazolium ionic liquid as base attached with two 2-mercapto-benzimidazole pods, whereas complex N3 contains a nonionic ligand. The synthesized copper complexes were evaluated for their catalytic activity for degradation of organophosphates. It is interesting that the complex containing the ionic ligand efficiently degrades phosphorothioate pesticides, whereas complex N3 was not found to be appropriate for degradation due to a weaker conversion rate. The organophosphate degradation studies were monitored by recording absorbance spectra of parathion in the presence of catalyst, i.e., copper complexes with respect to time. The parathion was hydrolyzed into para-nitrophenol and diethyl thiophosphate. Moreover, to analyze the inhibition activity of the pesticides toward acetylcholine esterase enzyme in the presence of prepared metal complexes, Ellman's assay was performed and revealed that, within 20 min, the inhibition of acetylcholine esterase enzyme decreases by up to 13%.


Assuntos
Acetilcolina/metabolismo , Esterases/metabolismo , Estruturas Metalorgânicas/química , Praguicidas/química , Praguicidas/toxicidade , Fosfatos/química , Acetilcolina/análise , Benzimidazóis/química , Catálise , Cobre/química , Cristalografia por Raios X , Esterases/análise , Estruturas Metalorgânicas/síntese química , Modelos Moleculares , Estrutura Molecular , Fosfatos/toxicidade
19.
Int J Biol Macromol ; 138: 1035-1043, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325508

RESUMO

Enzyme embedded metal-organic frameworks (MOFs) are blooming in the field of enzyme immobilization on account of their superior catalytic efficiency, thermal and chemical stability as compared to native enzyme. However, the separation and recovery of enzyme embedded MOF composite is quite challenging due to its nanometer size, high dispersity and low density which limits the reusability. In this work, α-amylase embedded zeolite imidazole framework (ZIF)-67 was fabricated onto melamine sponge using surfactant assisted dip coating technique. This was achieved in single pot making the method facile and rapid. α-Amylase MOF-sponge was analysed and characterized by FT-IR, XRD, SEM and TGA. We demonstrated that the encapsulation could maintain the active conformational structure of α-amylase after immobilization procedure with excellent bioactivity. Further, apart from merits of framework shielding, it offers mass transfer limitation for macromolecular substrate (like starch) which was determined and expressed as effectiveness factor (η) by using Michaelis-Menten enzyme kinetics. At the end, recycling studies were carried out for α-amylase MOF-sponge which showed 32% residual activity after six consecutive cycles. It is believed that this strategy has great potential in the field of continuous biotransformation (catalysis), biosensing and biomedicine application.


Assuntos
Técnicas de Química Sintética , Enzimas Imobilizadas , Estruturas Metalorgânicas/síntese química , alfa-Amilases/química , Ativação Enzimática , Estabilidade Enzimática , Cinética , Estruturas Metalorgânicas/química , Análise Espectral , Triazinas/química
20.
Inorg Chem ; 58(15): 9956-9963, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31290308

RESUMO

The research on luminescent lanthanide-functionalized covalent organic framework (COF)-based hybrid materials has not been reported so far. When a straightforward functionalized modification strategy is employed, a chemical stable Eu3+-modified COF hybrid material, Eu@TpPa-1, is first developed. The functional process does not affect the size and shape of TpPa-1, but after the introduction of Eu3+, Eu@TpPa-1 as a fluorescence sensor exhibits a turn-on response toward levofloxacin. Eu3+ plays a bridge role in the whole detection system, and TpPa-1 serves as a host matrix to provide protection for the introduced Eu3+. This reusable sensor shows strong pink-white and yellow emissions toward the high and low concentration ranges of levofloxacin, respectively. It displays excellent sensitivity and fast response to levofloxacin within 1 min, while refraining from the interference of other coexisting species in serum and urine. The good selectivity and high antidisturbance lead Eu@TpPa-1 to be successfully applied in serum and urine systems for sensing levofloxacin.


Assuntos
Európio/química , Fluorescência , Levofloxacino/sangue , Levofloxacino/urina , Estruturas Metalorgânicas/química , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Humanos , Medições Luminescentes , Estruturas Metalorgânicas/síntese química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA