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1.
Pharm Res ; 36(11): 152, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31463609

RESUMO

PURPOSE: To develop an analytical platform for the estimation as well as characterization of aggregates over the complete size spectrum (from invisible monomer to visible precipitates). METHODS: Two mAb samples were incubated at 30°C in different buffer systems of protein A chromatography for observing degradation due to aggregation. The aggregation in these samples was quantified by size exclusion chromatography (SEC), dynamic light scattering (DLS), and micro flow imaging (MFI). RESULTS: The results obtained from various characterization tools were analysed in various size ranges - size exclusion chromatography (SEC) (1 nm - 25 nm), dynamic light scattering (DLS) (10 nm - 5 µm), and micro flow imaging (MFI) (2 µm - 300 µm). Since each characterization tool covers a particular size range, data from multiple tools was collected in the "handover" regions to demonstrate accuracy of the platform. CONCLUSIONS: Based on the observations from the experiments, an analytical platform has been proposed covering the whole size spectrum that would be of utility to those engaged in formulation development as well as other aspects related to stability of biotherapeutic products.


Assuntos
Anticorpos Monoclonais/análise , Tampões (Química) , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Difusão Dinâmica da Luz , Nanopartículas/química , Tamanho da Partícula , Multimerização Proteica , Estabilidade Proteica
2.
Int J Nanomedicine ; 14: 4517-4528, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354271

RESUMO

Purpose: We developed a contrast agent for targeting E-selectin expression. We detected the agent using magnetic resonance imaging (MRI) in vivo in nude mice that had undergone nasopharyngeal carcinoma (NPC) metastasis. Methods: Sialyl Lewis X (sLeX) was conjugated with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles. Hydrodynamic size, polydispersity index, and ζ-potential of USPIO-polyethylene glycol (PEG) nanoparticles and USPIO-PEG-sLeX nanoparticles were measured. Component changes in nanoparticles of USPIO, USPIO-PEG, and USPIO-PEG-sLeX were analyzed by thermogravimetric analysis and Fourier-transform infrared spectroscopy. A model of NPC metastasis to inguinal lymph nodes in nude mice was used to investigate characteristics of the USPIO-PEG-sLeX nanoparticles in vivo. We investigated the ability of the T2* value, change in T2* value (ΔT2* value), and enhancement rate (ER) to assess accumulation of USPIO-PEG-sLeX nanoparticles quantitatively in mice of a metastasis group and control group. Four MRI scans were undertaken for each mouse. The first scan (t0) was done before administration of USPIO-PEG-sLeX nanoparticles (0.1 mL) via the tail vein. The other scans were carried out at 0 (t1), 1 (t2), and 2 hours (t3) postinjection. The mean optical density was used to reflect E-selectin expression. Results: sLeX was labeled onto USPIO successfully. In vivo, there were significant interactions between the groups and time for T2* values after administration of USPIO-PEG-sLeX nanoparticles. Six parameters (T2* at t2, ΔT2* at t1, ΔT2* at t2, ER at t1, ER at t2, and ER at t3) were correlated with the mean optical density. Conclusion: USPIO-PEG-sLeX nanoparticles can be used to assess E-selectin expression quantitatively. Use of such molecular probes could enable detection of early metastasis of NPC, more accurate staging, and treatment monitoring.


Assuntos
Dextranos/química , Selectina E/metabolismo , Nanopartículas de Magnetita/química , Animais , Linhagem Celular Tumoral , Dextranos/ultraestrutura , Difusão Dinâmica da Luz , Feminino , Metástase Linfática , Imagem por Ressonância Magnética , Nanopartículas de Magnetita/ultraestrutura , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias Nasofaríngeas/patologia , Metástase Neoplásica , Oligossacarídeos/metabolismo , Polietilenoglicóis/química , Eletricidade Estática , Termodinâmica
3.
J Agric Food Chem ; 67(32): 9104-9111, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31334655

RESUMO

Gold nanoflowers (GNFs) exhibit stronger light scattering ability than gold nanospheres (GNSs) with the same diameter, thereby contributing to enhancing the sensitivity of the scattering-based sensing method. However, the application of GNFs in biosensors based on dynamic light scattering (DLS) has not been yet reported. Herein, we describe for the first time an improved no-wash immunosensor based on dynamic light scattering for the detection of Escherichia coli O157:H7 (E. coli O157:H7) in milk using GNFs for sensitive signal transduction. To achieve this goal, a thiolated amphiphilic carboxyl ligand was introduced to modify the GNF surface and improve solution stability and antibody functionalization. Several key factors that affect the detection sensitivity of our developed GNF_DLS immunosensor were systematically investigated. Under the optimal conditions, our proposed GNF_DLS immunosensor provided an excellent linear detection for E. coli O157:H7 within the range from 6 × 100 to 6 × 104 colony-forming units (CFU)/mL, with a limit of detection of 2.7 CFU/mL. Combined with our previously reported two-step large-volume immunomagnetic separation (IMS) method, the designed GNF_DLS immunosensor can sensitively, selectively, and accurately detect the presence of E. coli O157:H7 in pasteurized milk. The potential of our GNF_DLS method for monitoring the presence of a single bacterial cell in 1 mL of sample solution was also demonstrated. Overall, the developed GNF_DLS immunosensor can be used for the rapid and high-sensitivity determination of pathogenic bacteria and can be extended for the ultrasensitive no-wash detection of other trace analytes.


Assuntos
Técnicas Biossensoriais/métodos , Difusão Dinâmica da Luz/métodos , Escherichia coli O157/isolamento & purificação , Leite/microbiologia , Animais , Técnicas Biossensoriais/instrumentação , Bovinos , Difusão Dinâmica da Luz/instrumentação , Escherichia coli O157/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Ouro/química , Leite/química , Nanoestruturas/química , Sensibilidade e Especificidade
4.
Analyst ; 144(17): 5186-5192, 2019 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-31343643

RESUMO

A reliable, highly sensitive and highly selective method of high performance liquid chromatography associated with resonance Rayleigh scattering (HPLC-RRS) was developed to detect three cytokinins, namely, 6-benzylaminopurine (BA), kinetin (KT) and zeatin (ZT). In this work, Pd(ii) is added into the system to form ternary ion association complexes for the first time, which results in a lower limit of detection and extends the application of HPLC-RRS. The experimental conditions were optimized. In order to investigate the reaction mechanism, the ternary ion association complexes were characterized by ultraviolet-visible spectrophotometry, dynamic light scattering, scanning electron microscopy and density functional theory calculations. In a HAc-NaAc buffer solution (pH = 4.1), a ternary complex of cytokinin : Pd(ii) : EryB (1 : 1 : 2) was formed. The detection limits (S/N = 3) of BA, KT, and ZT were 0.9, 1.5 and 2.3 ng mL-1, respectively. In addition, this method was applied for the simultaneous detection of cytokinins in real samples with satisfactory results.


Assuntos
Citocininas/análise , Compostos de Benzil/análise , Cromatografia Líquida de Alta Pressão , Difusão Dinâmica da Luz , Eritrosina/análise , Cinetina/análise , Limite de Detecção , Purinas/análise , Soja/química , Zeatina/análise
5.
Food Chem ; 298: 124987, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260962

RESUMO

In this study, subcritical water extraction (SWE), SWE in aqueous citric acid (pH 5.0) (SWEC), and ultrasound-assisted SWEC (USWEC) were used to extract soluble dietary fiber (SDF) from wheat bran. Results showed that SWE-based methods significantly influenced the physicochemical, functional, and biological properties of the SDF. The fraction SDF-III attained via USWEC had higher SDF yield (46.30%) and carbohydrate content (82.91%), and lower weight-average molecular weight (65.2 kDa) and particle size (1.17 µm), and looser and more porous surface structure, compared with the SDF-I and SDF-II obtained by SWE and SWEC, respectively. USWEC increased the thermal stability and homogeneity of SDF-III but decreased its apparent viscosity and dynamic viscoelasticity. Moreover, the SDF-III exhibited more significant antioxidant and α-amylase inhibitory activities in vitro than SDF-I and SDF-II. Therefore, the USWEC technique had a greater potential for the highly-efficient production of SDF from wheat bran.


Assuntos
Fracionamento Químico/métodos , Fibras na Dieta , Antioxidantes/química , Antioxidantes/farmacologia , Ácido Cítrico/química , Fibras na Dieta/farmacologia , Difusão Dinâmica da Luz , Inibidores Enzimáticos/farmacologia , Concentração de Íons de Hidrogênio , Peso Molecular , Monossacarídeos/análise , Tamanho da Partícula , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade , Água/química , alfa-Amilases/antagonistas & inibidores
6.
Int J Nanomedicine ; 14: 3273-3282, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190793

RESUMO

Background: Biotemplates are attractive templates for the synthesis of nanometals and inorganic compound nanostructures. Methods: In this work, for the first time, iron oxide quantum dot nanoparticles (QDNPs) were prepared using albumen as a biotemplate. Next, the prepared nanoparticles were characterized using dynamic light scattering for determination and evaluation of the hydrodynamic diameter and zeta potential of the particles. Moreover, optical and scanning electron microscopes were applied to evaluate morphology. Spherically shaped iron oxide QDNPs were obtained with appropriate particle size and distribution. Fe(NO3)3.9H2O and egg whites were used as the source of the Fe element and particle size control agent in the aqueous medium, respectively. Afterward, the effect of calcination temperature parameters on the crystallinity purity and size of Fe nanocrystals were investigated. Also, products were characterized by various detection analyses such as thermogravimetry analysis/DTA, XRD, UV-vis, Fourier transform infrared (FT-IR,) transmission electron microscopy, and SEM. In order to investigate the antibacterial effect of the synthesized Fe nanobiological samples against bacterial strains, they were dissolved in dimethyl sulfoxide and diluted using distilled water. Then, different serial dilutions of 64 µg/mL, 32 µg/mL, 16 µg/mL, 8 µg/mL, 4 3BCg/mL, 2 µg/mL, 1 µg/mL, and 0.5 µg/mL of nanobiological samples were prepared and added to the Mueller-Hinton agar medium. Results: The minimum inhibitory concentration of the synthesized iron oxide quantum dot nanobiological was determined against pathogenic microbial strains of bacteria including Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumonia on the culture medium plate. Conclusion: The present nanobiological samples can be considered as a new material candidate for antibacterial drugs.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Proteínas do Ovo/química , Compostos Férricos/química , Nanopartículas/química , Pontos Quânticos/química , Animais , Difusão Dinâmica da Luz , Camundongos , Testes de Sensibilidade Microbiana , Nanopartículas/ultraestrutura , Espectrofotometria Ultravioleta , Difração de Raios X
7.
Food Chem ; 293: 368-377, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151624

RESUMO

In this study, the efficiency and practical utilization feasibility of niosomal and liposomal nanovesicles loading Isoleucine-Proline-Proline (IPP) as suitable ingredients of functional beverages were evaluated. Vesicles were tailored by different preparation methods using phospholipid and non-ionic surfactants. The optimization process was performed by central composite design approach. The results of Fourier transform infrared spectroscopy demonstrated the compatibility of IPP with the vesicles. The phospholipidic nanovesicles, produced by modified ethanol injection-microchannel technique, were smaller with lower polydispersity index than non-ionic surfactant vesicles developed by the method of thin film hydration and probe sonication. However, niosomal model functional beverage exhibited more proper palatability, biological activity and physicochemical properties during long-term storage than liposomal one. Moreover, niosomes exhibited more sustained release behaviour in simulated blood fluid than liposomes. These findings are of great importance for design and development of the functional foods containing IPP.


Assuntos
Bebidas , Alimentos Fortificados , Nanoestruturas/química , Oligopeptídeos/química , Difusão Dinâmica da Luz , Manipulação de Alimentos/métodos , Armazenamento de Alimentos , Suco Gástrico/metabolismo , Humanos , Lipossomos/química , Microscopia Eletrônica de Transmissão , Oligopeptídeos/farmacocinética , Fosfolipídeos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tensoativos/química
8.
J Chromatogr A ; 1602: 409-418, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31171356

RESUMO

Determination of the number-based size distribution of silica particles using the centrifugal field-flow fractionation (CF3) method was investigated. Since the accurate determination of the number-based size distribution of materials is essential in the fields of nanotechnology and biotechnology, the establishment of a robust evaluation method is attractive. We explored optimization of the fractionation conditions for CF3 using silica particles. Using pure water media as the eluent, a band broadening effect was clearly found, and this effect became stronger with higher initial centrifugal field strengths. After addition of 0.05 wt% aqueous FL-70 as a dispersant in the eluent, size fractionation could be performed effectively at higher centrifugal field strengths, providing excellent size separation results. After optimization of the CF3 separation condition, we determined the number-based size distribution of silica particles using three methods: FE-SEM only, CF3 with multi-angle light scattering (CF3-MALS), and a combined CF3 with FE-SEM method (CF3-FE-SEM). To meaningfully compare the CF3-MALS results with the other two methods, we transformed the light scattering intensity to particle numbers using Mie theory. The determined number-based mean sizes of silica particles by the three methods agreed well; however, the evaluated standard deviation of the number-based size distribution of silica particles by the CF3-MALS method was slightly different. This was attributed to the unreliable sizing by MALS of smaller sized particles or low particle concentrations. The combined CF3-FE-SEM method provided near equal accuracy as the costly FE-SEM only and allowed for a significantly faster methodology because CF3 separation reduced the number of silica particles required for an accurate sizing down to just 50 particles per fraction.


Assuntos
Fracionamento por Campo e Fluxo/métodos , Tamanho da Partícula , Dióxido de Silício/química , Centrifugação , Difusão Dinâmica da Luz , Água
9.
Phys Chem Chem Phys ; 21(24): 13207-13214, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31179459

RESUMO

The local valence orbital structure of solid glycine, diglycine, and triglycine is studied using soft X-ray emission spectroscopy (XES), resonant inelastic soft X-ray scattering (RIXS) maps, and spectra calculations based on density-functional theory. Using a building block approach, the contributions of the different functional groups of the peptides are separated. Cuts through the RIXS maps furthermore allow monitoring selective excitations of the amino and peptide functional units, leading to a modification of the currently established assignment of spectral contributions. The results thus paint a new-and-improved picture of the peptide bond, enhance the understanding of larger molecules with peptide bonds, and simplify the investigation of such molecules in aqueous environment.


Assuntos
Modelos Químicos , Peptídeos/química , Difusão Dinâmica da Luz , Elétrons , Glicina/química , Glicilglicina/química , Oligopeptídeos/química , Teoria Quântica , Água/química , Difração de Raios X
10.
Biophys Chem ; 252: 106191, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31177024

RESUMO

Bacterial cell characteristics, such as size, morphology, and membrane integrity, are affected by environmental conditions. Thermal treatment results in related structural changes, extent of which is determined by the microorganism's survival skills and inactivation kinetics. The objective of this study was to characterize changes in cell structure of Escherichia coli during heating using the combined analysis of dynamic light scattering (DLS), electron paramagnetic resonance (EPR) spectroscopy, and transmission electron microscopy (TEM) techniques. The size of E. coli cells increased from 2.3 µm to 3.0 µm with heating up to 50 °C followed by a shrinkage with further heating up to 70 °C. The morphological changes were verified using transmission electron microscopy. Related changes in membrane integrity was quantified via the mobility of 16-doxylstearic acid (16-DSA) spin probe using EPR spectroscopy. Two order parameters S1 and S2 defined on x- and y-axes, respectively, decreased with increasing temperature indicating loss of membrane integrity. The combined techniques as in this study can be used to further understand factors that play role in survival behavior of microorganisms.


Assuntos
Membrana Celular/química , Escherichia coli/química , Escherichia coli/citologia , Calefação , Difusão Dinâmica da Luz , Espectroscopia de Ressonância de Spin Eletrônica , Hidrodinâmica , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Propriedades de Superfície
11.
Chemistry ; 25(47): 11058-11065, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31150560

RESUMO

The self-assembly of protein polymers is a promising route to prepare sophisticated functional nanostructures. However, the interplay between protein self-assembly by itself and its co-assembly with a template is not well understood. Silk-based protein polymers that co-assemble with DNA to form rod-like artificial viruses are herein developed and the effects of silk block length, concentration, and temperature in the self-assembly of the proteins alone are characterized by using a combination of bulk dynamic light scattering (DLS) and single-molecule atomic force microscopy (AFM). Protein nanorods were slowly formed (up to hours) through the interaction of the silk-like blocks. The proteins present a silk-length dependent critical elongation concentration, and above it the amount and size of nanorods rapidly increase. Temperature-dependent light scattering data was adequately fitted into a cooperative model of nucleation-elongation. These results are also important to understand the self-assembly of designed viral coat proteins with DNA templates to form artificial virus-like particles and help us to define general guidelines to design proteins with the ability to precisely organize matter at the nanoscale.


Assuntos
Proteínas do Capsídeo/química , Nanotubos/química , Sequência de Aminoácidos , Proteínas do Capsídeo/metabolismo , Difusão Dinâmica da Luz , Cinética , Microscopia de Força Atômica , Temperatura Ambiente
12.
Environ Sci Pollut Res Int ; 26(21): 21871-21881, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31134551

RESUMO

Utilization of non-host plants semiochemicals to mediate insect behavior offers a promising opportunity for novel management of insect pests in field crops and fruits. Therefore, there is still a substantial opportunity for the development of natural prophylactic as an eco-friendly approach in the novel pest management programs. Sophora alopecuroides extract has been used as a natural pesticide in the control of agricultural and household pests, but the low persistence effect and rapid biodegradability limit its use on a wider scale in pest management programs. In this study, an emulsifiable concentrate formulation containing S. alopecuroides extract (SAE-EC) was developed with a simple procedure and evaluated for its ovicidal, antifeedant, and repellent effects against Diaphorina citri under laboratory and semi-field conditions. Our results indicated that SAE-EC at 15, 30, and 50 mg/mL concentrations provide complete protection against psyllids for a period of 96 h after application both under laboratory and semi-field conditions, while the aqueous methanolic extract of S. alopecuroides loses its persistence 48 h after application. Furthermore, the emulsifiable concentrate at 20 and 30 mg/mL concentrations, only 15.97% and 31.97% of eggs were able to hatch, and at similar concentrations, 72.86% and 85.5% of honeydew secretion were reduced as compared to the control. SAE-EC at 30 mg/mL concentration has not shown any phytotoxic symptoms on Murraya paniculata seedlings. Fourier transform infrared (FTIR) study revealed the presence of alkaloids in emulsifiable concentrate after 3 months of its preparation placed under ambient temperature. Furthermore, the particle size and polydispersity index (PDI) of the emulsifiable concentrate were also confirmed by dynamic light scattering (DLS). Our finding indicated that emulsifiable concentrate formulation prolongs the persistence of S. alopecuroides extract and enhances its efficacy both under laboratory and semi-field conditions. It has been concluded that the emulsifiable concentrate formulation containing S. alopecuroides extract might be developed as an eco-friendly novel prophylactic against citrus psyllid.


Assuntos
Hemípteros/efeitos dos fármacos , Repelentes de Insetos/farmacologia , Extratos Vegetais/farmacologia , Sophora/química , Alcaloides/análise , Animais , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Difusão Dinâmica da Luz , Emulsões/química , Emulsões/farmacologia , Hemípteros/fisiologia , Controle de Insetos/métodos , Repelentes de Insetos/administração & dosagem , Repelentes de Insetos/química , Murraya/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Plântula/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Zigoto/efeitos dos fármacos
13.
Biosens Bioelectron ; 138: 111319, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31108381

RESUMO

A low-cost, effective and enzyme-free sensing strategy for ultrasensitive microRNA (miRNA) detection was developed based on dynamic light scattering (DLS) coupled with strand displacement reaction (SDR). The combination of DLS and SDR was used to assess the size changes of core-satellites nanoassembly. This strategy realized the limit of detection (LOD) as low as 0.24 pM (S/N = 3) and the detection range of 5 pM-150 pM, which might urge this strategy as an ideal candidate for the sensitive detection of miRNA in the future. In addition, the proposed strategy could be successfully used to analyze target miRNA in various cancer cells, indicating that the developed SDR-DLS strategy has promising clinical implications for rapid and early diagnosis of cancer-related diseases.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , MicroRNAs/análise , Técnicas Biossensoriais , Linhagem Celular Tumoral , Difusão Dinâmica da Luz , Humanos , Limite de Detecção , Tamanho da Partícula , Estudo de Prova de Conceito
14.
Int J Nanomedicine ; 14: 3069-3086, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31118623

RESUMO

Background: Synthetic HDLs (sHDLs), small nanodiscs of apolipoprotein mimetic peptides surrounding lipid bilayers, were developed clinically for atheroma regression in cardiovascular patients. Formation of HDL involves interaction of apolipoprotein A-I (ApoA-I) with phospholipid bilayers and assembly into lipid-protein nanodiscs. Purpose: The objective of this study is to improve understanding of physico-chemical aspects of HDL biogenesis such as the thermodynamics of ApoA-I-peptide membrane insertion, lipid binding, and HDL self-assembly to improve our ability to form homogeneous sHDL nanodiscs that are suitable for clinical administration. Methods: The ApoA-I-mimetic peptide, 22A, was combined with either egg sphingomyelin (eSM) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) phospholipid vesicles to form sHDL. The sHDL assembly process was investigated through lipid vehicle solubilization assays and characterization of purity, size, and morphology of resulting nanoparticles via gel permeation chromatography (GPC), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Peptide-lipid interactions involved were further probed by sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The pharmacokinetics of eSM-sHDL and POPC-sHDL nanodiscs were investigated in Sprague Dawley rats. Results: sHDL formation was temperature-dependent, with spontaneous formation of sHDL nanoparticles occurring only at temperatures exceeding lipid transition temperatures as evidenced by DLS, GPC, and TEM characterization. SFG and ATR-FTIR spectroscopy findings support a change in peptide-lipid bilayer interactions at temperatures above the lipid transition temperature. Lipid-22A interactions were stronger with eSM than with POPC, which resulted in the formation of more homogeneous sHDL nanoparticles with longer in vivo circulation time as evidenced the PK study. Conclusion: Physico-chemical characteristics of sHDL are in part determined by phospholipid composition. Optimization of phospholipid composition may be utilized to improve the stability and homogeneity of sHDL.


Assuntos
Apolipoproteína A-I/metabolismo , Lipoproteínas HDL/metabolismo , Nanopartículas/química , Peptídeos/metabolismo , Fosfolipídeos/metabolismo , Sequência de Aminoácidos , Animais , Apolipoproteína A-I/química , Difusão Dinâmica da Luz , Cinética , Bicamadas Lipídicas/química , Lipoproteínas HDL/química , Masculino , Nanopartículas/ultraestrutura , Peptídeos/química , Peptídeos/farmacocinética , Fosfatidilcolinas/administração & dosagem , Ratos Sprague-Dawley , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Esfingomielinas/administração & dosagem , Termodinâmica , Vibração
15.
Food Chem ; 294: 433-439, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126484

RESUMO

We have previously reported how the natural food colorant, bixin, was enzymatically modified by appending sorbitol to the bixin scaffold. The resulted product, sorbitol ester of norbixin (SEN) was expected to be more hydrophilic. The present study aimed to investigate the physical behaviour of SEN in aqueous media. The property of SEN was studied together with non-reacted bixin as separation of the two compounds was unsuccessful. The SEN molecules behaved as a bolaamphiphile in aqueous media, underwent self-association and develop a hydrophilic aggregate. SEN-aggregates could uptake the non-reacted bixin molecules inside its hydrophobic moiety and dispersed it in aqueous media. Aggregation of SEN molecules with incorporated bixin resulted in a hypsochromic shift of the absorption spectra indicting H-aggregation. Dynamic light scattering showed the formation of aggregates with an average hydrodynamic radius 38 ±â€¯2 nm. The dispersibility of the aggregates was affected by pH and the ionic strength of the media.


Assuntos
Carotenoides/química , Corantes de Alimentos/química , Sorbitol/química , Difusão Dinâmica da Luz , Ésteres/química , Furanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Nanoestruturas/química , Concentração Osmolar , Piridonas , Água/química
16.
Int J Nanomedicine ; 14: 2797-2807, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31118611

RESUMO

Introduction and objective: With the increase in carbon nanotube-based products on the commercial market, public concern regarding the possible toxicity of these nanomaterials has attracted much attention. Although previous studies found no obvious toxicity related to carbon nanotubes (CNTs), their safety has not been established because long-term evaluation is still needed. In vitro assays are used to understand the toxicity of nanomaterials. However, the data published so far were generated in short-term assays in which cells are continuously exposed to CNTs. Therefore, the objective of this study is to quantitatively assess the relative long-term cytotoxicity and degradation of CNTs after uptake by macrophages. Methods: We used macrophage cell line of RAW 264.7 and primary rat Kupffer cells to investigate macrophage uptake of CNTs as well as their quantity changes up to a relatively late time point after uptake (7 days) by measuring optical absorbance in the near infrared region and Raman spectra of CNTs in the cell lysates. The time-dependent cytotoxicity was evaluated by measuring reactive oxygen species (ROS), glutathione, cell viability, and caspase 3/7 activity in 1-7 days. Results: CNTs were degraded by approximately 25-30% within first 4 days after uptake; however, and no additional degradation occurred for the remainder of the 7-day test period. Generation of ROS by macrophages decreased as CNT degradation occurred, returning to control levels by Day 7. In the meantime, the glutathione level gradually recovered over time. There were no changes in cell viability or caspase 3/7 activation during CNT degradation. Conclusion: These results confirm that degradation of CNTs by macrophages is associated with ROS generation. The data also suggest that CNT cytotoxicity decreases as they are degraded.


Assuntos
Macrófagos/metabolismo , Nanotubos de Carbono/química , Espécies Reativas de Oxigênio/metabolismo , Animais , Morte Celular , Linhagem Celular , Sobrevivência Celular , Difusão Dinâmica da Luz , Macrófagos do Fígado/metabolismo , Camundongos , Nanotubos de Carbono/ultraestrutura , Células RAW 264.7 , Ratos , Fatores de Tempo
17.
Int J Nanomedicine ; 14: 2861-2877, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31118612

RESUMO

Background: Combination therapy remains a promising strategy for treating neurodegenerative diseases, although green synthesis of gold nanoparticles for treating chronic neuroinflammation and studying their efficacy in treating neuroinflammation-mediated neurodegenerative diseases is not well assessed. Results: Here, Ephedra sinica Stapf (ES) extract was used as the reducing, capping, and stabilizing agent for gold nanoparticle synthesis. We developed ES extract-capped gold nanoparticles (ES-GNs) and investigated their anti-neuroinflammatory properties in microglia. ES-GNs displayed maximum absorption at 538 nm in ultraviolet-visible spectroscopy. Dynamic light scattering assessment revealed that ES-GN diameter was 57.6±3.07 nm, with zeta potential value of -24.6±0.84 mV. High resolution-transmission electron microscopy confirmed the spherical shape and average diameter (35.04±4.02 nm) of ES-GNs. Crystalline structure of ES-GNs in optimal conditions was determined by X-ray powder diffraction, and elemental gold presence was confirmed by energy-dispersive X-ray spectroscopy. Fourier transform-infrared spectroscopy confirmed gold nanoparticle synthesis using ES. Anti-neuroinflammatory properties of ES-GNs on production of pro-inflammatory mediators (nitric oxide, prostaglandin E2, and reactive oxygen species) and cytokines (tumor necrosis factor-α, IL-1ß, and IL-6) in lipopolysaccharide (LPS)-stimulated microglia were investigated by ELISA and flow cytometry. ES-GNs significantly attenuated LPS-induced production of pro-inflammatory mediators and cytokines, which was related to suppressed transcription and translation of inducible nitric oxide synthase and cyclooxygenase-2, determined by RT-PCR and western blotting. ES-GNs downregulated upstream signaling pathways (IκB kinase-α/ß, nuclear factor-κB, Janus-activated kinase /signal transducers and activators of transcription, mitogen-activated protein kinase , and phospholipase D) of pro-inflammatory mediators and cytokines in LPS-stimulated microglia. Anti-neuroinflammatory properties of ES-GNs were mediated by ES-GNs-induced AMP-activated protein kinase)-mediated nuclear erythroid 2-related factor 2 /antioxidant response element signaling. Conclusion: Collectively, these findings provide a new insight on the role of ES-GNs in treating chronic neuroinflammation-induced neurodegenerative diseases.


Assuntos
Anti-Inflamatórios/farmacologia , Ephedra sinica/química , Ouro/farmacologia , Nanopartículas Metálicas/química , Microglia/patologia , Extratos Vegetais/farmacologia , Adenilato Quinase/metabolismo , Animais , Elementos de Resposta Antioxidante/genética , Antioxidantes/farmacologia , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ciclo-Oxigenase 2/metabolismo , Citocinas/metabolismo , Difusão Dinâmica da Luz , Mediadores da Inflamação/metabolismo , Nanopartículas Metálicas/ultraestrutura , Camundongos , Microglia/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
18.
Food Chem ; 294: 557-564, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126499

RESUMO

Superoxide dismutase (SOD) is an important enzyme with antioxidant function. The activity of purified SOD from chestnut rose was increased by 22.23-38.02% after high pressure processing (HPP, 100-500 MPa/0-20 min/30-50 °C). The properties of SOD induced by high pressure were studied by means of electrophoresis, dynamic light scattering, enthalpy and surface hydrophobicity, circular dichroism and fluorescence spectrometry. Results showed that high pressure did not change the electrophoretic properties, particle size distribution, digestive system stability and antioxidant capacity of SOD. However, the enthalpy and surface hydrophobicity of SOD was increased. The increase of SOD activity was related to the increase of SOD surface hydrophobicity. Moreover, the α-helix fraction of SOD was decreased by 8.7% and the intrinsic fluorescence intensity of SOD was increased by 5.7% when exposed to high pressure. This study suggested that HPP can be used as a novel way of increasing the activity of SOD in chestnut rose.


Assuntos
Proteínas de Plantas/metabolismo , Rosa/metabolismo , Superóxido Dismutase/metabolismo , Antioxidantes/metabolismo , Dicroísmo Circular , Difusão Dinâmica da Luz , Interações Hidrofóbicas e Hidrofílicas , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Pressão , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Superóxido Dismutase/química , Superóxido Dismutase/isolamento & purificação , Propriedades de Superfície
19.
Sci Total Environ ; 677: 502-510, 2019 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-31063893

RESUMO

Bisphenol A (BPA) in wastewater has high risks of causing biological feminization. During the wastewater treatment process, large amounts of BPA are accumulated in activated sludge. However, the mechanisms of BPA interacted with activated sludge are still unclear. Especially, the roles of extracellular polymeric substances (EPS), which are major components of activated sludge, in the removal of BPA have never been concerned. In this study, the binding interactions between sludge EPS and BPA are explored combining fluorescence spectroscopy and dynamic light scattering. The thermodynamic mechanisms driving the binding behavior of BPA to EPS are illustrated by isothermal titration calorimetry. The results indicate that the binding interaction between BPA and EPS is spontaneous. BPA mainly binds with the proteins of EPS by hydrophobic association. The random-coiled structure of EPS transforms into relatively condensed cores after binding with BPA. A neutral pH, high ionic strength, and high temperature promote the binding process, facilitating to stabilize BPA in sludge EPS. This study provides new insights into the roles of sludge EPS in the migration and removal of BPA in activated sludge system.


Assuntos
Compostos Benzidrílicos/química , Matriz Extracelular de Substâncias Poliméricas/química , Fenóis/química , Esgotos/análise , Poluentes Químicos da Água/química , Cromatografia em Gel , Difusão Dinâmica da Luz , Concentração de Íons de Hidrogênio , Íons/análise , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura Ambiente , Termodinâmica , Águas Residuárias/análise
20.
IET Nanobiotechnol ; 13(2): 183-188, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051449

RESUMO

Recently the use of medicinal plants potential in the production of nanoparticles has received serious attention. Here, the main component of Camellia sinensis L. (green tea) extract was detected by spectroscopy and the optimal conditions were determined for their performance in green synthesis of silver nanoparticles at room temperature. Epigallocatechin gallate was identified as the dominant component in the extract as determined by spectroscopy, and it was established that its oxidation was a function of the solution pH. Transmission electron microscopy, dynamic light scattering, and visible absorption spectroscopy (UV-Vis) confirmed the reduction in silver ions to silver nanoparticles (Ag NPs). Controlling over Ag NPs shape and narrow size distribution was achieved with 10 ml green tea leaf extract solution and in different reaction pH. Spherical colloidal Ag NPs with well-defined hydrodynamic diameters (with average hydrodynamic size of 27.9-50.2 nm) were produced. Silver nitrate concentrations used in this study were lower than that of reported in similar works, and synthesis efficiency was also higher. Nanoparticles were perfectly spherical and their uniformity, compared to similar studies, was much higher. These NPs showed higher degree of stability and were aqueously stable for >10 months in dark glasses at 4°C.


Assuntos
Camellia sinensis/química , Química Verde/métodos , Nanopartículas Metálicas/química , Prata/química , Chá/química , Antioxidantes/química , Catequina/química , Difusão Dinâmica da Luz , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier
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