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1.
J Chromatogr A ; 1626: 461349, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797829

RESUMO

In the present work, a very sensitive and fully automated direct immersion PAL SPME Arrow procedure, coupled with GC-MS, has been developed and validated for determination of nine phosphorus flame retardants in different types of water samples (river, drinking and rainwater). PDMS/DVB was selected among three commercially available SPME Arrows (PDMS/DVB, DVB/PDMS/CWR and PDMS/CWR), since it resulted in the best sensitivity. The important experimental parameters were optimized via a central composite design response surface methodology and as result, extraction time of 65 min, extraction temperature of 80 °C and added salt concentration of 19% (w/v), were selected as the optimum values. The optimized method showed linear response over the calibration range (2 - 500 ng L-1), with R2-values higher than 0.9937. The precision (RSD%) measured by replicate analyses (n = 7) was estimated at 2 and 100 ng L-1 and was less than 29% and 21%, respectively. The LOQ of PAL SPME Arrow, calculated as S/N = 10, was between 0.2 and 1.2 ng L-1 (for triphenyl phosphate and tris-(1­chloro­2-propyl) phosphate, respectively) with extraction efficiencies between 5.9 and 31% (for tris-(1,3-dichloro-2-propyl) phosphate and tri-n­butyl phosphate, respectively). To assess the performance of the developed technique for real samples, two river water samples, tap water from two regions and a rainwater sample were analyzed. Most of the target analytes were observed in the river samples with concentrations of 1.0 - 250 ng L-1 and the obtained recoveries at 50 ng L-1 ranged between 60 and 107%. Considering the figures of merit of the optimized method, PAL SPME Arrow-GC-MS showed to be the most sensitive analytical approach for determination of phosphorus flame retardants in water, with satisfying precision and accuracy, compared with conventional SPME-NPD, LLE-GC-MS and SPE-LC-MS/MS.


Assuntos
Retardadores de Chama/análise , Fósforo/análise , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Automação , Dimetilpolisiloxanos/química , Cromatografia Gasosa-Espectrometria de Massas , Polivinil/química , Soluções
2.
Food Chem ; 333: 127504, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32679416

RESUMO

The aim of this study is to extract zinc and manganese from foods and vegetables using an amphiphilic copolymer adsorbent, poly(styrene)-co-2-vinylpyridine which was synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization from styrene and 2-vinyl pyridine in the presence of a trithiocarbonate and 2,2'-azo-bis isobutyro nitrile (AIBN) in toluene solution under argon at 80 °C. Fourier Transform Infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy were used in the characterization of the obtained copolymer. Under the optimum conditions, several validation variables such as uncertainty measurement, selectivity, robustness, precisions, matrix effects and accuracy were investigated. Taking an adsorption time of 15 min, detection limits of 0.04 µg L -1 and 0.2 µg L-1and 7.9 µg L-1and enrichment factors of 145 and 110 were obtained for Mn(II) and Zn(II), respectively.The method was successfully applied to the analysis of Mn(II) and Zn(II) in foods and vegetables.


Assuntos
Manganês/isolamento & purificação , Poliestirenos/química , Polivinil/química , Extração em Fase Sólida/métodos , Verduras/química , Zinco/isolamento & purificação , Adsorção , Espectroscopia de Ressonância Magnética , Manganês/análise , Polimerização , Extração em Fase Sólida/instrumentação , Espectroscopia de Infravermelho com Transformada de Fourier , Zinco/análise
3.
Food Chem ; 331: 127277, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32544653

RESUMO

A novel nanocomposite poly(ethylene-co-vinyl acetate) (EVA) film with controlled in vitro release of iprodione (ID) was prepared. Chitosan (CS) was used as the reinforcement which enhances the water and oxygen permeability of films. ID loaded poly(ethylene glycol)-poly(ε-caprolactone) (PEG-PCL) (IPP) micelles were used as the drug carrier which endows the films with antifungal and controlled release ability. IPP micelles with spherical shape and uniform size were obtained, and the maximum encapsulation efficacy (EE) was 91.17 ± 5.03% by well controlling the feeding amount of ID. Incorporation CS could improve the oxygen and moisture permeability of films, and the maximum oxygen permeability (OP) and water vapor transmission rate (WVTR) were 477.84 ± 13.03 cc/(m2·d·0.1 MPa) and 8.60 ± 0.25 g m-2 d-1, respectively. After loading IPP micelles, the films showed an improved antifungal ability and temperature-sensitive drug release behavior, and were found to enhance the quality of grapes by pre-harvest spraying.


Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Hidantoínas/farmacocinética , Nanocompostos/química , Vitis/efeitos dos fármacos , Aminoimidazol Carboxamida/administração & dosagem , Aminoimidazol Carboxamida/farmacocinética , Quitosana/química , Preparações de Ação Retardada , Portadores de Fármacos , Microbiologia de Alimentos , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/farmacocinética , Hidantoínas/administração & dosagem , Lactonas/química , Micelas , Oxigênio , Permeabilidade , Polietilenoglicóis/química , Polivinil/química , Vapor
4.
Chemosphere ; 257: 127144, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32473409

RESUMO

Polyvinylidene fluoride (PVDF) membrane was coated with polyvinyl alcohol (PVA)/titanium dioxide (TiO2) solution using dip-coating method. The effect of PVA loading (0-12 wt%) at a fixed TiO2 concentration (1 wt%) was investigated through physical and morphological characterization of the membranes. The experimental results showed that increasing the PVA content from 0 to 12 wt% in the coating solution increased the hydrophilicity and tensile strength as well as the young's modulus of the coated membranes. It also increased the thickness of the thin film coating which enhanced the removal of dyes but affected the permeate flux adversely. Larger the molecular weight of the dye, higher the rejection and lower the permeate flux obtained. The antifouling performance of the membrane was studied using Bovine Serum Albumin (BSA) solution and the fouling was measured using the irreversible fouling factor. The results indicated that the PVA/TiO2 coated PVDF membrane had lower irreversible fouling factors compared to plain PVDF membrane. The PVDF membrane with a thin film coating containing 3 wt% of PVA and 1 wt% of TiO2 showed high photocatalytic degradation for the three dyes studied under UV irradiation due to uniform dispersion of TiO2 nanoparticles over the membrane surface. Further, smaller the molecular weight of the dye, larger the photodegradation that was observed.


Assuntos
Corantes/química , Álcool de Polivinil/química , Polivinil/química , Eliminação de Resíduos Líquidos/métodos , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Nanopartículas , Fotólise , Soroalbumina Bovina , Têxteis , Titânio , Raios Ultravioleta
5.
Food Chem ; 328: 127109, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32454261

RESUMO

Feijoa is a subtropical bush of the Myrtaceae family. It has unique fruit with organoleptic properties that make it an exotic fruit. Head space solid phase microextraction (HS-SPME) with a 65 µm divinylbenzene/polydimethylsiloxane (DVB/PDMS) fiber and gas chromatography coupled to mass spectrophotometry (GC-MS) was used to study the volatile fraction of feijoa fruit cultured in Caldas, Colombia. The profile analyzed included 134 volatile organic compounds (VOCs). 127 VOCs were classified based on the functional group using the spectral and structural networks correlation analysis. Methyl, ethyl and (Z)-3-hexenyl benzoate with 50% of the volatile composition, were the main compounds. Biosynthesis of the volatilome of feijoa fruit was associated with five main metabolic pathways. This study represents the first analysis of feijoa fruit commercialized in the region. This is an innovator view in elucidation of metabolic pathways that represent the biochemistry of the aroma of this fruit.


Assuntos
Feijoa/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Colômbia , Dimetilpolisiloxanos/química , Feijoa/metabolismo , Análise de Alimentos/métodos , Frutas/química , Frutas/metabolismo , Odorantes/análise , Polivinil/química
6.
AAPS PharmSciTech ; 21(5): 145, 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32430787

RESUMO

The present study demonstrates the solubility and dissolution of flufenamic acid (FLF)/ß-cyclodextrin (ß-CD)/Soluplus® supramolecular ternary inclusion complex. The binary and ternary inclusion complexes were prepared using solvent evaporation and the microwave irradiation method. The prepared inclusion complexes were evaluated for physicochemical characterization and anti-inflammatory activity using a murine paw edema mol. The phase solubility studies demonstrated 4.59-fold and 17.54-fold enhancements in FLF solubility with ß-CD alone and ß-CD:Soluplus® combination compared with pure FLF, respectively. The in vitro drug release results revealed a significant improvement (P < 0.05) in the release pattern compared with pure FLF. Maximum release was found with flufenamic acid binary and ternary complexes prepared using the microwave irradiation method, i.e., 75.23 ± 3.12% and 95.36 ± 3.23% in 60 min, respectively. The physicochemical characterization results showed complex formation and conversion of the crystalline form of FLF to an amorphous form. The SEM study revealed the presence of a more agglomerated and amorphous structure of the solid particles, which confirmed the formation of complexes. The anti-inflammatory effect of the complex was higher than pure FLF. Therefore, the FLF:ß-CD:Soluplus® inclusion complex may be a very valuable formulation with improved solubility, dissolution, and anti-inflammatory effect.


Assuntos
Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Ácido Flufenâmico/química , Ácido Flufenâmico/farmacologia , Polietilenoglicóis/química , Polivinil/química , beta-Ciclodextrinas/química , Animais , Varredura Diferencial de Calorimetria , Carragenina , Cristalização , Composição de Medicamentos , Edema/induzido quimicamente , Edema/patologia , Excipientes , Masculino , Micro-Ondas , Ratos , Ratos Wistar , Solubilidade , beta-Ciclodextrinas/farmacologia
7.
Pharm Res ; 37(6): 93, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32394114

RESUMO

PURPOSE: Here, first experiences with a prototype tool for high throughput (passive) permeability profiling, a 96-well plate comprising the Permeapad® membrane, are reported. The permeabilities of a set of drugs were determined and compared to published measures of oral absorption, such as human fraction absorbed (Fa) and in vitro permeability values obtained using other tools. METHODS: The tool consists of a 96-well bottom and screen plate with the artificial, phospholipid-based barrier (Permeapad®) mounted between the plates' lower and upper compartments. The permeability of 14 model compounds including high- and low-absorption drugs, cationic, anionic, zwitterionic and neutral molecules, was determined by quantifying the compounds' transport over time, deriving the steady-state flux from the linear part of the cumulative curves and calculating the apparent permeability (Papp). The membrane structure was investigated in a high-resolution digital light microscope. RESULTS: The Permeapad® 96-well plate was found suited to distinguish high and low absorption drugs and yielded a hyperbolic correlation to Fa. The Papp values obtained were congruent with those determined with in-house prepared Permeapad® in the Franz cell set-up. Furthermore, good to excellent correlations were seen with Caco-2 permeability (R2 = 0.70) and PAMPA permeability (R2 = 0.89). Microscopic investigation of the Permeapad® barrier revealed the formation of phospholipid vesicles and myelin figures in aqueous environment. CONCLUSION: The Permeapad® 96-well plate permeation set-up is a promising new tool for rapid and reproducible passive permeability profiling.


Assuntos
Portadores de Fármacos/química , Ensaios de Triagem em Larga Escala/métodos , Preparações Farmacêuticas/metabolismo , Fosfolipídeos/química , Células CACO-2 , Humanos , Membranas Artificiais , Modelos Biológicos , Modelos Químicos , Estrutura Molecular , Permeabilidade , Polivinil/química , Soluções/química , Relação Estrutura-Atividade
8.
J Oleo Sci ; 69(6): 539-547, 2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32404546

RESUMO

Highly efficient nanocomposite electrolytes were prepared by mixing the montmorillonite (MMT) clay nanofillers and iodide poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) gel electrolytes for the purpose of measuring the performance of quasi-solid-state dye-sensitized solar cells (QS-DSSCs). The impacts of different amounts of MMT nanofillers on the ion diffusivity, conductivity of the polymer gel electrolytes (PGEs), and the photovoltaic performance of the cells using the PGEs were evaluated. The results indicated that the use of 5 wt.% MMT markedly increase the ion diffusivity and conductivity of the PVDF-HFP PGE. The introduction of 5 wt.% nanofillers considerably reduced the Warburg diffusion resistance, which made to the high performance of the QS-DSSCs. Cells utilizing 5 wt.% MMT nanofillers were shown to obtain a power conversion efficiency (PCE) (6.77%) higher than that obtained for cells using pure PGEs and identical to that obtained using liquid electrolytes (LEs) (6.77%). The high PCE was a result of an enhance in the current density in the presence of the 5 wt.% MMT nanofillers. The DSSC efficiency was found to maintain 99.9% of its initial value after 194 h of testing at 60℃ under dark environments. The stability of the DSSC using PGEs with the optimal amount of MMT nanofillers was higher than that for the cells using liquid electrolyte and pure PGE.


Assuntos
Bentonita/química , Corantes , Eletrólitos/química , Iodetos/química , Nanocompostos/química , Polivinil/química , Energia Solar , Géis , Polímeros
9.
Chemosphere ; 253: 126649, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32268250

RESUMO

The novel highly hydrophilic composite additive, graphene oxide-polyethylene glycol (GO-PEG, further abbreviated as P-GO), was synthesized from GO and PEG by the esterification reaction. Then, P-GO was blended into a polyvinylidene fluoride (PVDF) casting solution as an additive, and the effects of P-GO on the performance of the PVDF ultrafiltration (UF) membrane were researched. When amount of added P-GO was 0.5 wt%, the flux of the resultant modified membrane (denoted as P/0.5P-GO) reached as high as 93 L m-2·h-1, that is twice than that of the pure PVDF membrane (45 L m-2·h-1). Furthermore, water contact angle results confirmed significantly improved hydrophilicity of the P/0.5P-GO membrane. Results of antifouling tests revealed that the P/0.5P-GO membrane showed the lowest total resistance and irreversible resistance among all the membranes prepared in this study, and after physical cleaning, its flux recovery ratio was the highest-78%. These results demonstrated improved antifouling performance of the P/0.5P-GO membrane. Therefore, it can be concluded that P-GO as an additive material for the PVDF membrane has satisfactory performance in improving the membrane hydrophilicity, permeability, and antifouling performance in practical applications.


Assuntos
Nanocompostos/química , Polietilenoglicóis/química , Polivinil/química , Purificação da Água/métodos , Grafite , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Permeabilidade , Ultrafiltração/métodos
10.
Chemistry ; 26(20): 4489-4495, 2020 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-32073730

RESUMO

It is challenging to design metal catalysts for in situ transformation of endogenous biomolecules with good performance inside living cells. Herein, we report a multifunctional metal catalyst, ruthenium-coordinated oligo(p-phenylenevinylene) (OPV-Ru), for intracellular catalysis of transfer hydrogenation of nicotinamide adenine dinucleotide (NAD+ ) to its reduced format (NADH). Owing to its amphiphilic characteristic, OPV-Ru possesses good self-assembly capability in water to form nanoparticles through hydrophobic interaction and π-π stacking, and numerous positive charges on the surface of nanoparticles displayed a strong electrostatic interaction with negatively charged substrate molecules, creating a local microenvironment for enhancing the catalysis efficiency in comparison to dispersed catalytic center molecule (TOF value was enhanced by about 15 fold). OPV-Ru could selectively accumulate in the mitochondria of living cells. Benefiting from its inherent fluorescence, the dynamic distribution in cells and uptake behavior of OPV-Ru could be visualized under fluorescence microscopy. This work represents the first demonstration of a multifunctional organometallic complex catalyzing natural hydrogenation transformation in specific subcellular compartments of living cells with excellent performance, fluorescent imaging ability, specific mitochondria targeting and good chemoselectivity with high catalysis efficiency.


Assuntos
Complexos de Coordenação/química , Mitocôndrias/química , Polivinil/química , Rutênio/química , Catálise , Hidrogenação , Interações Hidrofóbicas e Hidrofílicas , Mitocôndrias/metabolismo , Nanopartículas , Água
11.
Carbohydr Polym ; 230: 115606, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887878

RESUMO

In this research, biocomposite films containing chitosan (CS), polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), with different ratios, have been provided. The effects of adding hexamethylene 1, 6-di(aminocarboxysulfonate) (HMDACS) as cross-linking agent and the formation of urethane linkage on mechanical properties such as tensile strength, elongation and dynamic-mechanical properties such as storage modulus and tan δ were studied. Also, the antibacterial properties of the composites were investigated by viable bacterial cell counting and compared in reducing the bacterial growth. The final results showed the composite containing CS (50 wt%), PVA (30 wt%), PVP (20 wt%) and HMDACS (2 wt%) had the highest mechanical properties. Scanning electron microscopy (SEM) micrographs confirmed uniform distribution of components in the polymer matrix. In general, low contact angle values revealed the hydrophilicity of the prepared films. It was found that the composites made by combining CS, PVA and PVP at concentration of 50, 25, 25 wt% (A3) and 60, 20, 20 wt% (B4), cross-linked with 2 wt% HMDACS, had the best antibacterial activity against Escherichia coli and Staphylococcus aureus, hence they can be used as promising materials for the preparation of wound dressings.


Assuntos
Curativos Hidrocoloides , Quitosana/análogos & derivados , Nanocompostos/química , Uretana/química , Antibacterianos/química , Antibacterianos/farmacologia , Reagentes para Ligações Cruzadas/química , Escherichia coli/efeitos dos fármacos , Interações Hidrofóbicas e Hidrofílicas , Polivinil/química , Staphylococcus aureus/efeitos dos fármacos
12.
Pharm Res ; 37(2): 28, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31912250

RESUMO

PURPOSE: This study aims to conduct an impact investigation in the hydrophobic-hydrophilic balance as an important factor for dissolution improvement of a hydrophilic carrier-based solid dispersion system. METHODS: Polymeric carriers with different hydrophobic to hydrophilic ratios were used to prepare several electrospun solid dispersion formulations. Physicochemical properties and surface morphology of the samples were assessed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), polarized light microscopy, Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRPD) and Scanning Electron Microscopy (SEM). Dissolution study was conducted in a non-sink condition to assess the drug release. RESULTS: Incorporation of a higher amount of hydrophilic component showed an improvement in formulating a fully amorphous system based on XRPD, yet the dissolution rate increment showed no significant difference from the lower. Hence, the degree of crystallinity is proven not to be the crucial factor contributing to dissolution rate improvement. The presence of a concomitant hydrophobic component, however, showed ability in resisting precipitation and sustaining supersaturation. CONCLUSION: Hydrophobicity in a binary carrier system plays an important role in achieving and maintaining the supersaturated state particularly for an amorphous solid dispersion. Graphical Abstract.


Assuntos
Antimaláricos/química , Atovaquona/química , Portadores de Fármacos/química , Polivinil/química , Povidona/química , Cristalização , Composição de Medicamentos , Liberação Controlada de Fármacos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Cinética , Solubilidade , Solventes/química
13.
Macromol Rapid Commun ; 41(4): e1900613, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31958201

RESUMO

In the present work, poly(methyl methacrylate) (PMMA) is successfully grafted onto poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) side chains via directly activated CF bonds using Cu(0)/2,2'-bipyridine as catalyst. The reaction mechanism and the initiating sites can be confirmed by the structure of the graft copolymer. The graft copolymerization exhibits first-order kinetics, and reaction conditions can affect the chemical composition of the graft copolymer, including reaction time, reaction temperature, solvents, the amount of catalyst, and monomer. The introduction of rigid PMMA side chains onto P(VDF-TrFE) can effectively tune the displacement-electric field hysteresis behaviors of P(VDF-TrFE) from normal ferroelectric to anti-ferroelectric, even linear-like dielectric, under high electric field, resulting in dramatically reduced energy loss while maintaining the discharged energy density. This work may provide an effective strategy to introduce functional groups into P(VDF-TrFE) copolymer via activation of CF bonds.


Assuntos
Polimetil Metacrilato/química , Polivinil/química , Catálise , Cinética , Polimerização
14.
Carbohydr Polym ; 231: 115730, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31888809

RESUMO

Low-cost and highly sensitive piezoelectric sensors were fabricated from bacterial cellulose (BC)/MnFe2O4 nanocomposite films via a co-precipitation method, followed by hot-pressing. MnFe2O4 nanoparticles were homogeneously distributed in the BC structure. The piezoelectric sensitivity measurements in the normal mode showed that the pristine BC film exhibited a sensitivity of ∼5 pC/N, whereas this value was increased to 23 pC/N for the composite film, which is comparable to the PVDF reference film. In the bending mode, the piezoelectric response increased to 25 pC/N and 57 pC/N for the BC film and the composite film, respectively. Moreover, the piezoelectric sensitivity was significantly enhanced using carbon tape electrodes attached directly to the films instead of sandwiched electrodes. This produced a sensitivity of greater than 50 pC/N for the MBC nanocomposite film in the normal mode measurement. Our work demonstrates the potential of using MBC composite films as inexpensive and highly sensitive flexible piezoelectric sensors.


Assuntos
Celulose/química , Nanocompostos/química , Nanopartículas/química , Bactérias/química , Carbono/química , Eletrodos , Compostos Férricos/química , Compostos de Manganês/química , Polivinil/química
15.
Talanta ; 209: 120581, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31892020

RESUMO

Conjugated polyelectrolytes (CPEs) have been widely used as reporters in colorimetric assays targeting nucleic acids. CPEs provide naked eye detection possibility by their superior optical properties however, as concentration of target analytes decrease, trace amounts of nucleic acid typically yield colorimetric responses that are not readily perceivable by naked eye. Herein, we report a pixelated analysis approach for correlating colorimetric responses of CPE with nucleic acid concentrations down to 1 nM, in plasma samples, utilizing a smart phone with an algorithm that can perform analytical testing and data processing. The detection strategy employed relies on conformational transitions between single stranded nucleic acid-cationic CPE duplexes and double stranded nucleic acid-CPE triplexes that yield distinct colorimetric responses for enabling naked eye detection of nucleic acids. Cationic poly[N,N,N-triethyl-3-((4-methylthiophen-3-yl)oxy)propan-1-aminium bromide] is utilized as the CPE reporter deposited on a polyvinylidene fluoride (PVDF) membrane for nucleic acid assay. A smart phone application is developed to capture and digitize the colorimetric response of the individual pixels of the digital images of CPE on the PVDF membrane, followed by an analysis using the algorithm. The proposed pixelated approach enables precise quantification of nucleic acid assay concentrations, thereby eliminating the margin of error involved in conventional methodologies adopted for interpretation of colorimetric responses, for instance, RGB analysis. The obtained results illustrate that a ubiquitous smart phone could be utilized for point of care colorimetric nucleic acids assays in complex matrices without requiring sophisticated software or instrumentation.


Assuntos
Colorimetria/métodos , Ácidos Nucleicos/sangue , Polieletrólitos/química , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Cátions/química , Colorimetria/instrumentação , Desenho de Equipamento , Humanos , Ácidos Nucleicos/análise , Papel , Sistemas Automatizados de Assistência Junto ao Leito , Polímeros/química , Polivinil/química , Smartphone , Tiofenos/química
16.
Sensors (Basel) ; 20(3)2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31979190

RESUMO

Development of stretchable electronics has been driven by key applications such as electronics skin for robotic or prosthetic. Mimicking skin functionalities imposes at a minimal level: stretchability, pressure, and temperature sensing capabilities. While the research on pressure sensors for artificial skin is extensive, stretchable temperature sensors remain less explored. In this work, a stretchable temperature and infrared sensor has been developed on a polydimethylsiloxane substrate. The sensor is based on poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) as a pyroelectric material. This material is sandwiched between two electrodes. The first one consists of aluminium serpentines, covered by gold in order to get electrical contact and maximum stretchability. The second one is based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) that has shown good electrical compatibility with PVDF-TrFE and provides the stretchability of the top electrode. Without poling the PVDF-TrFE, sensor has shown a sensitivity of around 7 pF.°C-1 up to 35% strain without any change in its behaviour. Then, taking advantage on infrared absorption of PEDOT:PSS, a poled device has shown a pyroelectric peak of 13 mV to an infrared illumination of 5 mW at 830 nm. This stretchable device valuably allows an electronic skin (e-skin) use for contact and more importantly non-contact thermal sensing.


Assuntos
Técnicas Biossensoriais/métodos , Dispositivos Eletrônicos Vestíveis , Polivinil/química , Temperatura
17.
Int J Biol Macromol ; 148: 737-749, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31978468

RESUMO

Electrospun nanofibrous Guar gum/PVA based scaffold matrix incorporated with standardized extracts of four traditional medicinal plants of wound healing repute namely - Acalypha indica (A.i), Aristolochia bracteolata (A.b), Lawsonia inermis (L.i) and Thespesia populnea (T.p) was developed. Combinatorial ratio optimization of the extracts subject to their impact on nanofibre morphology, thermal and swelling stability resulted in a 4:4:1:1 blend of A.i, A.b, T.p and L.i at 20% of the total weight of the polymer mix. Dermal toxicity studies on female wistar rats established the nontoxicity of the generated Scaffold/Dressing. Cutaneous wound healing ability of Mesenchymal Stem Cells (MSC's) is well characterized to amplify their delivery and efficacy at the wound site. Apart from ease of accessibility, increased immune modulation of Gingival MSC's is their clear merit relative to those conventionally sourced from adipose tissues and bone marrow. A population of cells were isolated from discarded sample of human gingiva, following standard procedures and characterized as per minimal criteria as described by International Society for Cellular Therapy's (ISCT). The Cytocompatibility and proliferation of GMSC's were evaluated by MTT and Calcein AM assay demonstrating the viability of the seeded GMSC's up to 6 days. In vivo efficacy of the scaffold with and without GMSC's showed complete restoration of the tissue with minimal scarring. This investigation thus generated an herb drug enriched nanofibrous mat as a dressing and also a skin like scaffold with GMSC's, integrating the biological and technological benefits of herbal medicine and stem cell therapy respectively for skin regenerative applications.


Assuntos
Materiais Biocompatíveis/química , Cyamopsis/química , Medicamentos de Ervas Chinesas/química , Galactanos/química , Mananas/administração & dosagem , Mananas/química , Mananas/isolamento & purificação , Nanofibras/química , Gomas Vegetais/química , Tecidos Suporte/química , Animais , Bandagens , Fosfatos de Cálcio/química , Adesão Celular , Proliferação de Células , Dextranos/química , Feminino , Humanos , Células-Tronco Mesenquimais/metabolismo , Nanocompostos/química , Polivinil/química , Ratos Wistar , Sementes/química , Propriedades de Superfície , Fatores de Tempo , Engenharia Tecidual
18.
Prep Biochem Biotechnol ; 50(1): 18-27, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31453751

RESUMO

We report on the development of a functionalized membrane-based technology for selective enrichment of milk fat globules from raw bovine milk. Functionalization was conducted by in situ polymerization of acrylic acid within a polyvinylidene fluoride membrane, followed by the electrostatic attachment of a cationic polymer to impart a net positive charge. The functionalized membrane-based technology enabled a one-step method of selective separation of globules directly from milk-based on size and charge. The presence of globules in the eluate was confirmed by fluorescence microscopy. Quantification of the extracted phospholipids from globules in the eluant revealed a significantly higher amount of polar lipids than the permeate. Our study describes a comprehensive analysis of selective enrichment of fat globules using a functionalized membrane and demonstrates the beneficial effect of extracted phospholipids from enriched fat globules.


Assuntos
Glicolipídeos/isolamento & purificação , Glicoproteínas/isolamento & purificação , Membranas Artificiais , Leite/química , Polivinil/química , Animais , Bovinos , Fracionamento Químico/métodos , Glicolipídeos/análise , Glicoproteínas/análise , Fosfolipídeos/análise
19.
J Photochem Photobiol B ; 202: 111722, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31785445

RESUMO

Nowadays, the study of well-known sensitizers for photodynamic therapy and search for new ones are intensively conducted. In the present work supramolecular organization of crown-ether and phosphoryl-containing phthalocyanines ({Mgcr8Pc, I, and М[R4Pc] (M = Zn2+, R = -OPhP(O)(OH)(OC5H11), II; M = 2H+, R = -OPhP(O)(OH)(OC5H11), III; M = 2H+, -OPhP(O)(OH)2), IIIa}, respectively) was studied in microheterogeneous media. The role of a metal ion of a macrocycle in monomerization of phosphoryl-containing Pc in the presence of water-soluble poly(N-vinylpyrrolidone) was revealed. Some photobiological properties of compound I as possible photosensitizer with respect to human adenocarcinoma cells, HeLa, were analyzed. So, the light and dark cytotoxicity of I (IC50 dose) was 1.83 µÐœ and higher than 25 µÐœ, respectively. The reactive oxygen species (ROS) formation studied with use of fluorescent ROS detector DCFH2 revealed the plateau on the curves of fluorescence intensity vs time after 30 min of irradiation and ROS are almost not produced after the end of irradiation. In HeLa cells, accumulation of compounds I and II as well as fluorescent DCF presence were shown by confocal microscopic images. At concentration of 5 µM, compound I easily penetrates into the cell localizing primarily in the perinuclear region, whereas compound II mainly remains in the periphery of the cells in the fluorescent-active state. The results obtained allow us to continue the study of these interesting compounds.


Assuntos
Éteres de Coroa/química , Indóis/química , Metais/química , Fármacos Fotossensibilizantes/química , Polivinil/química , Pirrolidinas/química , Espécies Reativas de Oxigênio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células HeLa , Humanos , Luz , Microscopia Confocal , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/farmacologia
20.
Chemosphere ; 241: 125068, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31629244

RESUMO

This paper reports a novel nanocomposite additive for a polyvinylidene fluoride (PVDF) membrane with high hydrophilicity through the association of graphene oxide (GO) and ZnO. The influence of the hydrophilicity of GO-ZnO on the PVDF membrane was examined on different GO-ZnO loadings. The porosity and wettability (or hydrophilicity) of the membrane were improved significantly by blending GO-ZnO nanocomposite. In addition, the water flux of the GO-ZnO/PVDF membrane was 48% higher than that of bare PVDF, and the anti-fouling properties of this modified membrane were also improved. The irreversible fouling ratio (Rir) of bovine serum albumin (BSA) was reduced substantially with increasing the loading of GO-ZnO nanocomposite. The lowest irreversible fouling ratio (7.21%) was obtained for the membrane containing 0.2 wt % GO-ZnO of the nanocomposite (M6). GO-ZnO modification PVDF membranes were assumed to reduce the affinity between membrane and BSA foulant, which improved the anti-fouling properties PVDF membrane. In the activated sludge flux test, the membrane containing GO-ZnO in the polymer matrix had a higher flux than that of the bare PVDF membrane. The effluent quality after the composite membrane (0.6 NTU) was stable, indicating that the composite membrane can be used for practical applications Overall, the properties of the PVDF membrane were improved after modification due to hydrogen bonding or the hydrophilicity of the GO-ZnO nanocomposite.


Assuntos
Grafite/química , Polivinil/química , Ultrafiltração , Eliminação de Resíduos Líquidos/métodos , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Nanocompostos , Nanopartículas/química , Polímeros , Porosidade , Soroalbumina Bovina , Óxido de Zinco/química
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