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1.
Biomed Res Int ; 2021: 5544196, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33834066

RESUMO

Objectives: The aim of this study was to evaluate the protective effect of using four different fluoride bioactive enamel sealers against an acidic erosion challenge. Materials and Methods: A sample of 50 freshly extracted sound upper premolars had their buccal surface bonded to 50 orthodontic brackets using Transbond PLUS color change adhesive; the first four groups had four compositions of fluoride bioactive glasses based on 37 mol% SiO2, 43.9-53.9 mol% CaO, 6.1 mol% P2O5 and CaF2, and 0-10 mol% of Na2O applied to their surfaces and the fifth group served as control (which was not treated by any bioactive sealer). All specimens were challenged by 1% citric acid for 18 minutes which was stirred by a magnetic stirrer. The enamel surfaces next to the orthodontic brackets were examined by SEM. The Wilcoxon signed-rank test was used to compare the area covered by the fluoride bioactive pastes before/after erosion (p < 0.05). Samples from the layer formed on top of the examined teeth were tested before/after erosion to be examined by the attenuated total reflectance Fourier-transform infrared spectroscopy (FTIR/ATR). Results: The FTIR/ATR test showed that fluoride bioactive pastes' applications resulted in the formation of a hydroxyapatite-rich layer; the SEM analysis showed that the aforementioned layer significantly resisted erosion challenge when compared to the control group (p < 0.05). Conclusions: Fluoride bioactive pastes can efficiently protect the enamel surfaces next to orthodontic brackets from acidic erosion challenges.


Assuntos
Esmalte Dentário/efeitos dos fármacos , Fluoretos/farmacologia , Vidro/química , Braquetes Ortodônticos , Substâncias Protetoras/farmacologia , Simulação por Computador , Cristalização , Esmalte Dentário/ultraestrutura , Selantes de Fossas e Fissuras , Resinas Sintéticas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
2.
Molecules ; 26(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668087

RESUMO

Stereolithography is a useful additive manufacturing technique for the production of scaffolds for tissue engineering. Here we present a tuneable, easy-to-manufacture, photocurable resin for use in stereolithography, based on the widely used biomaterial, poly(caprolactone) (PCL). PCL triol was methacrylated to varying degrees and mixed with photoinitiator to produce a photocurable prepolymer resin, which cured under UV light to produce a cytocompatible material. This study demonstrates that poly(caprolactone) methacrylate (PCLMA) can be produced with a range of mechanical properties and degradation rates. By increasing the degree of methacrylation (DM) of the prepolymer, the Young's modulus of the crosslinked PCLMA could be varied from 0.12-3.51 MPa. The accelerated degradation rate was also reduced from complete degradation in 17 days to non-significant degradation in 21 days. The additive manufacturing capabilities of the resin were demonstrated by the production of a variety of different 3D structures using micro-stereolithography. Here, ß-carotene was used as a novel, cytocompatible photoabsorber and enabled the production of complex geometries by giving control over cure depth. The PCLMA presented here offers an attractive, tuneable biomaterial for the production of tissue engineering scaffolds for a wide range of applications.


Assuntos
Materiais Biocompatíveis/química , Poliésteres/química , Resinas Sintéticas/química , Estereolitografia , Engenharia Tecidual , Tecidos Suporte/química , Materiais Biocompatíveis/síntese química , Estrutura Molecular , Processos Fotoquímicos , Poliésteres/síntese química , Resinas Sintéticas/síntese química , beta Caroteno/química
3.
Food Chem ; 352: 129367, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33684718

RESUMO

About 90% of grapefruit in Florida are affected by Huanglongbing (HLB). HLB negatively affects the organoleptic properties of grapefruit juice because affected trees overproduce bitter secondary-metabolites, mostly naringin. The objective of this research was to remove naringin from HLB-affected grapefruit juice using microporous-adsorbents and to investigate how debittering affected narirutin, limonoids, bergamottin, and consumer acceptability. The adsorption kinetics of naringin on seven adsorbent resins obeyed pseudo-second order. PAD550 and PAD600 showed better static adsorption/desorption. Adsorption-isotherms on these resins were better fitted on Temkin-Pyzhev-model. On a fixed-bed-column packed with PAD550 resin, a slower loading rate increased its breakthrough volume before naringin in effluent reached its taste-threshold. In addition to naringin being reduced to below its taste-threshold, debittering significantly decreased the content of limonin, nomilin, and bergamottin. A consumer taste panel rated debittered and half-debittered juices higher for overall acceptability than the untreated. The half-debittered juice was ranked the most preferred while untreated was the least preferred.


Assuntos
Citrus paradisi/química , Citrus paradisi/microbiologia , Sucos de Frutas e Vegetais/análise , Furocumarinas/análise , Doenças das Plantas/microbiologia , Resinas Sintéticas/química , Paladar , Porosidade
4.
J Chromatogr A ; 1642: 462037, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33714768

RESUMO

Two solid phase extraction resins (SPER) were prepared by impregnating solutions of two diglycolamide-functionalized calix[4]arenes in 10% isodecanol in n-dodecane into Chromosorb W, as the stationary phase. While SPER-I contained n-propyl functionalized calix[4]arene, SPER-II contained the calix[4]arene with isopentyl groups at the carboxamide nitrogen atoms. The SPERs were characterized by SEM, TGA, FTIR, etc. and were used for the batch uptake of neptunium(IV) from nitric acid feed solutions. While the uptake of Np(IV) was extremely high with SPER-I (Kd: 47,544 at 3 M nitric acid, ca. 8% extractant loading), SPER-II displayed a significantly lower extraction efficiency (Kd: 13,724 under identical conditions) as indicated by the batch uptake studies. Sorption isotherm studies were carried out which indicated good fitting to the Langmuir model suggesting uptake conforming to monolayer sorption. Fitting to the D-R isotherm model conformed to a chemisorption model. Column studies were also carried out and the elution profiles, obtained with solutions of oxalic acid and nitric acid indicated very sharp peaks suggesting that the column can be used for the separation of Np(IV) from acidic radioactive feeds.


Assuntos
Calixarenos/química , Glicolatos/química , Netúnio/análise , Ácido Nítrico/química , Fenóis/química , Resinas Sintéticas/química , Extração em Fase Sólida/métodos , Adsorção , Íons , Cinética , Ligantes , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Fatores de Tempo
5.
J Vis Exp ; (167)2021 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-33554959

RESUMO

The morphology, size and quantity of cells, starch granules and protein bodies in seed determine the weight and quality of seed. They are significantly different among different regions of seed. In order to view the morphologies of cells, starch granules and protein bodies clearly, and quantitatively analyze their morphology parameters accurately, the whole-seed-sized section is needed. Though the whole-seed-sized paraffin section can investigate the accumulation of storage materials in seeds, it is very difficult to quantitatively analyze the morphology parameters of cells and storage materials due to the low resolution of the thick section. The thin resin section has high resolution, but the routine resin sectioning method is not suitable to prepare the whole-seed-sized section of mature seeds with a large volume and high starch content. In this study, we present a simple dry sectioning method for preparing the whole-seed-sized resin section. The technique can prepare the cross and longitudinal whole-seed-sized sections of developing, mature, germinated, and cooked seeds embedded in LR White resin, even for large seeds with high starch content. The whole-seed-sized section can be stained with fluorescent brightener 28, iodine, and Coomassie brilliant blue R250 to specifically exhibit the morphology of cells, starch granules, and protein bodies clearly, respectively. The image obtained can also be analyzed quantitatively to show the morphology parameters of cells, starch granules, and protein bodies in different regions of seed.


Assuntos
Microtomia/métodos , Resinas Sintéticas/química , Sementes/química , Zea mays/química , Proteínas de Plantas/metabolismo , Sementes/citologia , Coloração e Rotulagem , Amido/metabolismo , Zea mays/citologia , Zea mays/embriologia
6.
J Chromatogr A ; 1640: 461948, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33561708

RESUMO

Fast-throughput and cost reduction of current purification platforms are becoming increasing requests during antibody manufacture. The macroporous-matrix absorbents have presented extensive potentiality in improving operational throughput during purification of macromolecule. And meanwhile the peptide ligand has become a promising alternative to recombinant protein ligands for cost reduction of chromatographic purification. Therefore, here we designed a functionalized microspheres resin with both macroporous matrix of polymerized glycidyl methacrylate and ethylene glycol dimethacrylate (PGMA-EDMA) and peptide ligand of hexapeptide (FYEILH). In order to circumvent the steric effect of peptides and amplify the binding sites on macroporous matrix, the peptide ligand was coupled on a liner PGMA polymer brushes grafted on microspheres. Comparing to the conventional agarose-matrix resin and the general peptide-grafted microspheres, the functionalized microspheres presented excellent permeability and high capacity to rapid loading hIgG by maintaining a stable level of dynamic binding capacity at fast flow rate above 110 column volume per hour (cv/h) and very short residence time below 0.5 min. Such functionalized microspheres provide a facile and broadly applicable strategy to develop the attractive candidate for rapid and cost-reduced purification of antibody.


Assuntos
Anticorpos Monoclonais/isolamento & purificação , Imunoglobulina G/isolamento & purificação , Microesferas , Peptídeos/química , Polímeros/química , Adsorção , Animais , Células CHO , Cromatografia , Cricetulus , Difusão , Humanos , Ligantes , Permeabilidade , Polimerização , Porosidade , Domínios Proteicos , Proteínas Recombinantes/química , Resinas Sintéticas/química , Sefarose/química , Soroalbumina Bovina/química , Proteína Estafilocócica A/química , Propriedades de Superfície
7.
J Chromatogr A ; 1641: 461999, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33611122

RESUMO

Low molecular weight diglycolamide (DGA) extractants were tested for the extraction of europium(III) and americium(III) from nitric acid solutions in n-dodecane, a molecular diluent and 1-butyl-3-methylimidazolium bis(trifluoromethanesulphonyl) imide (C4mim⋅NTf2), a room temperature ionic liquid, as the diluents. N,N,N',N'-tetra-n-butyl diglycolamide (TBDGA) was selected for extraction chromatography (XC) studies involving Eu(III) and Am(III). While the TBDGA resin containing n-dodecane gave reasonably high Kd values, that containing the ionic liquid showed higher Eu(III) uptake values. Compared to Eu(III), Am(III) was extracted by the resins to a lower extent. The loaded Eu(III) was back extracted from the resin using 0.05 M EDTA solutions in a buffered medium containing 1 M guanidine carbonate. Reusability studies indicated that, while the ionic liquid-based resin can be conveniently recycled five times with very marginal decrease in the percentage extraction values, there was a sharp decrease in the percent extraction after three cycles with the n-dodecane-based resin. The uptake data was fitted into different isotherm models and the results conformed to the Langmuir model. Based on the batch uptake studies, columns were prepared and the breakthrough as well as elution profiles were obtained. The elution profiles were found to be sharp without any significant tailing.


Assuntos
Cromatografia/métodos , Glicolatos/química , Líquidos Iônicos/química , Ácido Nítrico/química , Resinas Sintéticas/química , Amerício/química , Cátions , Európio/química , Imidazóis/química , Ligantes , Solventes/química , Temperatura , Termogravimetria , Fatores de Tempo
8.
Nat Protoc ; 16(2): 561-578, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33473197

RESUMO

Solid-phase synthesis represents the methodological showcase for technological advances such as split-and-pool combinatorial chemistry and the automated synthesis of peptides, nucleic acids and polysaccharides. These strategies involve iterative coupling cycles that do not generate functional diversity besides that incorporated by the amino acids, nucleosides and monosaccharide building blocks. In sharp contrast, multicomponent reactions (MCRs) are traditionally used to generate both skeletal and appendage diversity in short, batchwise procedures. On-resin MCRs have traditionally been employed for the construction of heterocycle and peptidomimetic libraries, but that scenario has changed recently, and today the focus is more on the solid-phase derivatization of peptides and oligonucleotides. This review presents relevant experimental details and addresses the synthetic scope of such on-resin multicomponent protocols employed to accomplish specific biopolymer covalent modifications that are practically inviable by traditional solution-phase methodologies. Recommendations are provided to facilitate the implementation of solid-supported protocols and avoid possible pitfalls associated with the selection of the polymeric resin, the solvent and the order and amount of the reagents employed. We describe procedures comprising the multicomponent lipidation, biotinylation and labeling of both termini and the side chains, as well as the use of MCRs in the traceless on-resin synthesis of ligated and cyclic peptides. Solid-phase protocols for the assembly of α-helical and parallel ß-sheet peptides as well as hybrid peptide-peptoid and peptide-peptide nucleic acid architectures are described. Finally, the solid-supported multicomponent derivatization of DNA oligonucleotides is illustrated as part of the DNA-encoded library technology relying on MCR-derived heterocyclic compounds.


Assuntos
Biopolímeros/química , Técnicas de Química Combinatória/métodos , Técnicas de Síntese em Fase Sólida/métodos , Aminas , Aminoácidos , Biopolímeros/biossíntese , Biotinilação , DNA , Compostos Heterocíclicos , Oligonucleotídeos , Peptídeos/síntese química , Peptídeos Cíclicos , Resinas Sintéticas/química
9.
J Chromatogr A ; 1637: 461843, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-33412291

RESUMO

The manufacturability of therapeutic monoclonal antibodies is limited by the harsh conditions that antibodies are subjected to during the purification procedure, which in turn restricts the development of novel acid-sensitive antibodies. The gold standard for antibody purification, Protein A affinity chromatography, offers the selective capture of antibodies with great yields, but also poses a threat to the quality of the antibodies. Antibodies and Fc-fusion proteins risk forming aggregates as a consequence of the acidic elution from the Protein A ligands, compromising the potency and safety of the drug. Here, we present a novel, mild purification strategy based on a calcium-dependent ligand derived from Protein A, called ZCa. Antibodies captured on a high-capacity tetrameric ZCa resin in the presence of calcium can be eluted by removing the calcium ions through the addition of a chelator, and we describe the strive to find a sustainable alternative to the previously applied chelator EDTA. The naturally occurring chelator citrate is shown to seamlessly replace EDTA. Further buffer optimization reveals that the elution can be considerably improved by increasing the conductivity through the addition of 300 mM sodium chloride, leading to a very concentrated eluate. Remarkably, merely sodium chloride at a concentration of 50 mM is proven to be sufficient for calcium-dependent antibody release in a cost-efficient manner. Antibodies of subclasses IgG2 and IgG4 are eluted with sodium chloride at neutral pH and IgG1 at pH 6, due to varying affinities for the tetrameric ZCa, ranging between 90-780 nM. The mild elution of an IgG4 antibody eliminated the formation of aggregates, which constituted as much as 34% of all eluted antibody from MabSelect SuRe at pH 3. This novel purification strategy thus combines the valuable qualities of a Protein A resin, by providing high selectivity and a recovery of 88-99%, with an exceptionally mild elution step similar to ion-exchange chromatography, rendering considerably more functional antibody.


Assuntos
Anticorpos Monoclonais/isolamento & purificação , Resinas Sintéticas/química , Cloreto de Sódio/química , Proteína Estafilocócica A/química , Animais , Células CHO , Cálcio/química , Cromatografia por Troca Iônica , Citratos/química , Cricetinae , Cricetulus , Cristalografia por Raios X , Ácido Edético/química , Humanos , Concentração de Íons de Hidrogênio , Imunoglobulina G/química , Ligantes , Peso Molecular
10.
Food Chem ; 338: 128150, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33092007

RESUMO

This study aimed to develop efficient adsorption and desorption processes to purify phenolic compounds from Ecklonia cava. We compared the adsorption and desorption properties of five resins. HP2MG showed the highest adsorption and desorption capacities and adsorption rate; hence, it was selected for phenolic compound purification. Adsorption isotherm parameters indicated favorable adsorption between HP2MG and phenolic compounds. Thermodynamic parameters showed that the absorption process physically proceeded. In the dynamic adsorption process, adsorption property was assessed based on bed length (4-10 cm) and flow rate (1.64-3.27 mL/min). The breakthrough point increased with increased bed length and decreased adsorption flow rate. However, the high desorption flow rate shortened the processing time. The phenolic contents, anti-glycation activity and antioxidant activity of the extract were measured before and after purification. The dieckol and phlorofucofuroeckol-A increased three times after purification. The purified extract showed higher anti-glycation and antioxidant activities than the extract.


Assuntos
Feófitas/química , Fenóis/química , Resinas Sintéticas/química , Adsorção , Fenóis/isolamento & purificação , Porosidade , Termodinâmica
11.
Niger J Clin Pract ; 23(9): 1312-1317, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32913173

RESUMO

Objective: The present study compared the ability of bleaching, resin infiltration and microabrasion to restore the appearance of existing white spot lesions (WSL) on tooth surfaces as close as possible to that of the original healthy enamel. Materials and Methods: Sixty extracted human teeth with WSL were randomly assigned to three treatment groups (20/group). Prior to treatment, the colour of the surrounding healthy enamel and the WSL were measured as the baseline and pre-treatment (PreRX) colours respectively using spectrophotometer based on CIE L*A*B. The L-value was used for the statistical comparison. WSLs in each group were treated respectively by bleaching, infiltration or microabrasion following the manufacturer's instructions. Colour measurement was repeated after treatment. Both intragroup and intergroup comparisons were performed using ANOVA followed by Tukey's multiple comparison test (α=0.05). Result: In all groups the mean L-values were significantly higher in PreRX WSL (P < 0.01; Tukey) compared to baseline (sound enamel). After treatment the difference in mean L-value between baseline and WSL increased significantly (P < 0.01, Tukey) in Bleaching and Microabrasion groups by 1.4% and 1% respectively, but decreased in Infiltration group by 3.4%. Thus resin infiltration decreased the L-value of the WSL, bringing it closer to the L-value of the sound enamel while bleaching and microabrasion increased the L-value. Conclusions: Among the three treatment modalities investigated in this study, resin infiltration was the most effective in masking the WSLs.


Assuntos
Cárie Dentária/terapia , Microabrasão do Esmalte , Estética Dentária , Resinas Sintéticas/uso terapêutico , Clareamento Dental/métodos , Biometria , Cárie Dentária/patologia , Humanos , Resinas Sintéticas/química , Espectrofotometria , Descoloração de Dente , Resultado do Tratamento
12.
Chemosphere ; 260: 127589, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32682135

RESUMO

Although recycled plastics provide a low-cost and environmentally friendly alternative for many applications, their desirability is significantly limited by the presence of unpleasant odors from volatile organic compounds (VOCs). In this work, a headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) method was optimized to analyze volatile compounds from an odorous recycled plastic resin which was roughly composed of 85-90% polypropylene (PP) and 15-10% high-density polyethylene (HDPE). A large variety of aliphatic hydrocarbons and 13 additive residues were detected. Statistical tools were employed to screen the VOCs and successfully identified three components, i.e., 2,4-dimethyl-heptane, 4-methyl-octane and octamethylcyclotetrasiloxane (D4), which were significantly related to the odor intensity of the recycled plastic resin (p-values < 0.05). 2,4-Dimethyl-heptane has a strong, pungent plastic smell, which is very similar to the odor of the recycled resin. It is identified as a major source of the odor. Past relevant research has not been able to establish a direct link between an odorous compound and the undesirable odor of recycled plastic until now. 4-Methyl-octane was highly corelated to 2,4-dimethyl-heptane and somewhat contributed to the odor. D4 does not have an odor, but it may serve as an indicator of some odorous residues from personal care products.


Assuntos
Odorantes/análise , Resinas Sintéticas/química , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Plásticos/química , Polietileno/química , Polipropilenos/química , Reciclagem
13.
Food Chem ; 331: 127312, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32619907

RESUMO

Growing interest in the health benefits of soy isoflavones has led to research in the isolation of individual isoflavone species for further application. Herein, we develop a new strategy to isolate daidzein, genistein, daidzin and genistin in soybean. We investigated the impact of solvents used and the extraction time on the extracted isoflavone contents from soybean. A 30-min extraction with 65% aqueous methanol gave a total isoflavone yield of 345 mg/100 g soybean, the highest value among tested conditions. Further, we proposed a two-stage adsorption/desorption chromatography comprising macroporous resin and aluminium oxide to isolate isoflavone. First, HP-20 resin was used to separate the glucosidic and aglyconic forms of isoflavone, then individual species of isoflavone could be isolated using aluminium oxide by specific retention of 5-hydroxy isoflavone. This process achieved overall high recovery (82-97%) and purity (92-95%) of the four isoflavones, which confirms a high separating efficiency for isoflavones from soybean.


Assuntos
Óxido de Alumínio/química , Isoflavonas/isolamento & purificação , Resinas Sintéticas/química , Solventes/química , Soja/química , Isoflavonas/análise , Isoflavonas/química , Porosidade , Resinas Vegetais
14.
Chemosphere ; 260: 127590, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32679376

RESUMO

A new treatment method using a deep eutectic solvent embedded melamine sponge (DES-MS) was studied for the removal of organic pollutants from water and soil samples. Five organophosphorus pesticides (OPPs) consisting of azinphos-methyl (AZP), parathion-methyl (PRT), fenitrothion (FNT), diazinon (DIZ) and chlorpyrifos (CPF), and two dyes including acid blue 29 (AB29) and malachite green (MG) were used as the model pollutants. DESs were easily prepared from tetrabutylammonium bromide (TBABr) and various fatty acids. The synthesised DESs were loaded into the sponge before being utilized for the removal of the studied pollutants. After the removal, the residual OPPs or dyes in the supernatant was quantified by high performance liquid chromatography or derivative spectrophotometry, respectively. The proposed method was simple, rapid, environmentally friendly and effective with the removal efficiency higher than 70% for various samples. Moreover, the removal of various dyes was successfully achieved with the efficiency greater than 65% under the optimum condition.


Assuntos
Corantes/análise , Praguicidas/análise , Resinas Sintéticas/química , Poluentes do Solo/análise , Solventes/química , Triazinas/química , Poluentes Químicos da Água/análise , Recuperação e Remediação Ambiental/métodos , Limite de Detecção , Solo/química , Águas Residuárias/química , Purificação da Água/métodos
15.
J Chromatogr A ; 1625: 461300, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709343

RESUMO

Multi-column continuous chromatography has advantages of high resin capacity utilization and productivity, low buffer consumption and small footprint. Experimental optimization is often time-consuming and inefficient due to the complexity of continuous processes. In this study, a model-based approach was investigated to improve process development of twin-column continuous capture with Protein A affinity resin MabSelect PrismA. Breakthrough curves under various conditions, productivity and capacity utilization (CU) of the continuous processes under varying operating conditions were predicted. Effects of three key operating parameters (feed concentration (c0), interconnected feed residence time (RT) and breakthrough percentage control of the first column during interconnected feeding (s)) on the productivity and CU were evaluated. A recommended working window can be determined directly from contour maps to balance the trade-off between productivity and CU. The model-optimized operating conditions at varying feed concentrations were verified by experiments, which indicated that the model-based approach was feasible and reliable. The results showed that the suitable RT was 1~2 min and suitable s was 0.6~0.75 for the continuous IgG capture with MabSelect PrismA. The maximum productivity varied from 14 to 47 g/L/h with the feed IgG concentrations at the range of 1 to 10 mg/mL. The results indicated that model-based approach could assist process development efficiently and promote target-orientated process design for continuous processes.


Assuntos
Cromatografia de Afinidade/métodos , Modelos Teóricos , Resinas Sintéticas/química , Proteína Estafilocócica A/química , Humanos , Reprodutibilidade dos Testes , Fatores de Tempo
16.
ACS Nano ; 14(7): 8846-8854, 2020 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-32578981

RESUMO

The COVID-19 pandemic is endangering the world due to the spread of respiration droplets with viruses. Medical workers and frontline staff need to wear respirators to protect themselves from breathing in the virus-containing respiration droplets. The most frequently used state-of-the-art respirators are of N95 standard; however, they lack self-decontamination capabilities. In addition, the viruses and bacteria can accumulate on the respirator surfaces, possessing high risks to the wearers over long-term usage. Photothermal decontamination is a contactless, fast, low-cost, and widely available method, capable of decontaminating the respirators. Herein, we report a plasmonic photothermal and superhydrophobic coating on N95 respirators, possessing significantly better protection than existing personal protection equipment. The plasmonic heating can raise the surface temperature to over 80 °C for this type of respirator within 1 min of sunlight illumination. The superhydrophobic features prohibit respiration droplets from accumulating on the respirator surfaces. The presence of the silver nanoparticles can provide additional protection via the silver ion's disinfection toward microbes. These synergistic features of the composite coatings provide the N95 respirator with better protection and can inspire experts from interdisciplinary fields to develop better personal protection equipment to fight the COVID-19 pandemic.


Assuntos
Desinfecção/métodos , Desenho de Equipamento/métodos , Máscaras/normas , Equipamento de Proteção Individual/normas , Impressão Tridimensional , Dispositivos de Proteção Respiratória/normas , Infecções por Coronavirus/prevenção & controle , Desenho de Equipamento/instrumentação , Temperatura Alta , Humanos , Interações Hidrofóbicas e Hidrofílicas , Lasers , Máscaras/virologia , Nanopartículas Metálicas/química , Pandemias/prevenção & controle , Equipamento de Proteção Individual/virologia , Pneumonia Viral/prevenção & controle , Resinas Sintéticas/química , Dispositivos de Proteção Respiratória/virologia , Prata/química , Luz Solar
17.
J Chromatogr A ; 1623: 461197, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505286

RESUMO

Trifluoromethyl covalent organic framework (CF3-COF) is facilely synthesized at room temperature using for solid-phase microextraction (SPME). The CF3-COF coating displays an improved extraction performance for per- and polyfluorinated alkyl substances (PFASs) comparing to amorphous polymer coating, non-contained fluorine covalent organic framework coating and commercially available SPME coating. The fluorine affinity of trifluoromethyl in CF3-COF for PFASs is demonstrated using the density functional theory calculation. Following the microextraction with CF3-COF-coated fiber, the targeted PFASs are eluted with 1 mL acetonitrile and quantified by ultrahigh performance liquid chromatography tandem mass spectrometry. The low limits of detection are 0.1-0.7 pg g-1 for milk and 0.2-0.8 pg g-1 for milk powder, suggesting the outstanding sensitivity. The precision for the method ranges between 2.9 and 9.9%. The fiber-to-fiber repeatability is in the range of 4.2-9.5%. Under the optimum conditions, the relative recoveries are 91.0-110% with RSDs ≤ 10% for milk and 89.8-111% with RSDs ≤ 10% for milk powder.


Assuntos
Hidrocarbonetos Halogenados/isolamento & purificação , Estruturas Metalorgânicas/química , Leite/química , Microextração em Fase Sólida/métodos , Adsorção , Animais , Citrullus/química , Sucos de Frutas e Vegetais/análise , Glioxal/química , Concentração de Íons de Hidrogênio , Estruturas Metalorgânicas/síntese química , Fenóis/química , Reprodutibilidade dos Testes , Resinas Sintéticas/química , Ureia/química
18.
J Chromatogr A ; 1621: 461079, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32360061

RESUMO

Capto™ Core 700 is a core-shell chromatographic support with an adsorbing core contained within an inert shell layer designed to purify larger biomolecules and bioparticles in a flow-through mode. The present study aims to characterize the structure and functional properties of this resin using bovine serum albumin (BSA, Mr~65 kDa) and thyroglobulin (Tg, Mr~660 kDa) as model impurity proteins. The functionalized adsorbing core and the inert shell have the same fibrous structure typical of agarose-based beads. The resin average bead size is 90.7 µm with a range of 50-130 µm, the shell thickness is 4.18 µm with a range of 3-6 µm and a standard deviation of 0.55 µm, and the pore radius, obtained by inverse size exclusion chromatography, is 50.4 ± 1.3 nm. Both proteins present highly favorable binding isotherms with maximum binding capacities of 55 and 105 mg/mL of total bead volume for BSA and Tg, respectively. The addition of 500 mM NaCl reduces the binding capacity by less than 50%, showing the ability of the resin to operate at high salt conditions. For both proteins, the effective pore diffusivity in the core is smaller than in the shell due to additional hindrance by bound protein in the core area. Effective pore diffusivities values in the core are 1.6 × 10-7 and 0.16 × 10-7 cm2/s for BSA and Tg, respectively. The DBC10% at 2 min residence time are 24 and 2 mg/mL for BSA and Tg, respectively. This study provides qualitative and quantitative information about Capto™ Core 700 resin. This information could be used to predict and optimize the purification of large biomolecules and bioparticle in route to the establishment of more effective downstream processes.


Assuntos
Cromatografia em Gel/métodos , Tamanho da Partícula , Adsorção , Animais , Bovinos , Resinas Sintéticas/química , Soroalbumina Bovina/química , Temperatura , Tireoglobulina/química
19.
Chem Commun (Camb) ; 56(16): 2507-2510, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32003763

RESUMO

Radiolabeling of peptides with fluorine-18 is hurdled by their chemical sensitivity and complicated processes. Original triflyl-pyridine intermediates afforded ammonium precursors that were radiolabeled at low temperature. From that study, a generic tag has been designed to allow a simple one-step/late-stage radiolabelling of peptides. The strategy has been transposed to an automated "on-resin" radiolabelling.


Assuntos
Peptídeos/síntese química , Compostos Radiofarmacêuticos/síntese química , Resinas Sintéticas/síntese química , Radioisótopos de Flúor , Halogenação , Estrutura Molecular , Peptídeos/química , Compostos Radiofarmacêuticos/química , Resinas Sintéticas/química , Temperatura
20.
Anal Chim Acta ; 1104: 1-9, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32106938

RESUMO

Electromembrane extraction (EME) in small, stagnant and chip-like devices has the potential for future in-field operation. Literature briefly discuss such systems, but performance suffered from evaporative losses of sample and acceptor. To address this, the current paper reports electromembrane extraction (EME) of five basic drugs (model analytes) from aqueous buffer solutions and whole blood samples under stagnant conditions in a completely closed system. A laboratory-made polyoxymethylene (POM) well plate served as compartment for the sample solution, while a commercially available well filter plate was used to immobilize 2-nitrophenyl octyl ether (NPOE) as supported liquid membrane (SLM) and as closed compartment for the acceptor solution. Major design parameters (sample compartment and electrode geometry) and operational parameters (sample volume, voltage and extraction time) were investigated and optimized. Electrode geometry was not very critical, but extraction efficiency increased with decreasing sample volume. Extraction from 50 µL aqueous buffer solution for 60 min and with a voltage of 75 V was considered exhaustive (sample was depleted), with recoveries ranging between 75% and 87% for loperamide, haloperidol, methadone, nortriptyline, and pethidine (RSD: 2-12%). Extraction from whole blood samples under optimized conditions yielded slightly lower recoveries, ranging between 57 and 96% (RSD: 3-12%). Stagnant EME was evaluated in combination with liquid chromatography-mass spectrometry (LC-MS) as a highly specific instrumental method, and provided evaluation data on methadone from blood samples in accordance with regulatory requirements (LOD: 0.4 ng/mL, LOQ: 1.4 ng/mL, RSD: 6-20%). This work has improved upon the design of stagnant EME, moving it further towards a viable in-field operation device.


Assuntos
Técnicas Eletroquímicas/métodos , Membranas Artificiais , Preparações Farmacêuticas/análise , Tampões (Química) , Cromatografia Líquida , Técnicas Eletroquímicas/instrumentação , Eletrodos , Éteres/química , Voluntários Saudáveis , Humanos , Limite de Detecção , Espectrometria de Massas , Preparações Farmacêuticas/sangue , Resinas Sintéticas/química
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