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1.
Sci Total Environ ; 692: 1201-1208, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539951

RESUMO

Colloidal particles in lake waters interact inevitably with cyanobacterial extracellular polymeric substance (EPS), which will change their behavior and fate. Quantitative prediction of the effects of cyanobacterial EPS on colloidal behavior is difficult due to its variability and heterogeneity. To explore the effects of molecular weight (MW) fractions and chemical properties of cyanobacterial EPS on aggregation kinetics of colloidal particles, time-series cyanobacterial samples were collected in Lake Taihu, China, from April to November (during blooming and maintenance period), with the bulk EPS matrix fractionating into low MW (LMW-, <1 nm) and high MW (HMW-, 1 nm-0.45 µm) fractions. HMW-EPS was generally characterized with higher absorbance and predominant distribution of protein-like substances, while LMW-EPS contained mainly the humic- and fulvic-like substances. The absorbance, molecular size, and humification degree for each MW fraction consistently increased from April to November, showing obvious temporal variations from blooming period to maintenance period. As for the MW-dependent aggregation behaviors, the HMW-EPS provided better stability against aggregation than the LMW-EPS, and the bulk EPS matrix that consisted of HMW- and LMW-fractions exhibited the effects intermediate between that of each fraction alone. Regardless of MW fractions, the effects of EPS-induced stability enhancement were more evident in maintenance period than in blooming period. Further analysis showed that the colloidal stability was correlated positively with SUVA254 (R2 = 0.82-0.93) but negatively with Slope275-295 (R2 = 0.53-0.91) of UV-Vis absorption spectra, indicating that aromaticity and MWs were two critical parameters controlling colloidal aggregation. Therefore, cyanobacterial EPS can exhibit variable effects on colloidal stability, and characterization of MW distribution is strongly required in predicating the behavior and fate of colloidal particles in water environments.


Assuntos
Coloides/química , Cianobactérias , Matriz Extracelular de Substâncias Poliméricas , China , Eutrofização , Cinética , Lagos/química , Peso Molecular , Polímeros
2.
J Agric Food Chem ; 67(35): 9719-9726, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31398015

RESUMO

Pickering high internal phase emulsions (HIPEs) are normally highly concentrated emulsions stabilized by colloidal particles with a minimum internal phase volume fraction of 0.74. They have received considerable attention in many fields, including pharmaceuticals, tissue engineering, foods, and personal care products. The aim of this perspective is to update the current knowledge on the field of protein-based Pickering HIPEs, emphasizing those aspects that need to be explored and clarified. Research progress in constructing HIPEs by protein-type colloid particles and promising research trends in basic research and potential applications were highlighted. Promising studies in this field include (1) clarifying bioavailability and evolution of activity of active ingredients in Pickering HIPEs by oral administration, (2) constructing a Pickering interfacial catalysis platform using protein colloidal particles, and (3) expanding the emerging applications of Pickering HIPEs in fields, such as partially hydrogenated oil replacers, probiotic encapsulation, and the template for porous materials.


Assuntos
Suplementos Nutricionais/análise , Emulsões/química , Proteínas/química , Coloides/química , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Excipientes/química , Nanopartículas/química , Tamanho da Partícula , Porosidade
3.
Environ Pollut ; 252(Pt B): 1491-1499, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31265960

RESUMO

Understanding the influence of colloids on radionuclide migration is of significance to evaluate environmental risks for radioactive waste disposals. In order to formulate an appropriate modelling framework that can quantify and interpret the anomalous transport of Strontium (Sr) in the absence and presence of colloids, the continuous time random walk (CTRW) approach is implemented in this work using available experimental information. The results show that the transport of Sr and its recovery are enhanced in the presence of colloids. The causes can be largely attributed to the trap-release processes, e.g. electrostatic interactions of Sr, colloids and natural sediments, and differences in pore structures, which gave rise to the varying interstitial velocities of dissolved and, if any, colloid-associated Sr. Good agreement between the CTRW simulations and the column-scale observations is demonstrated. Regardless of the presence of colloids, the CTRW modelling captures the characteristics of non-Fickian anomalous transport (0 < ß < 2) of Sr. In particular, a range of 0 < ß < 1, corresponding to the cases with greater recoveries, reveal strongly non-Fickian transport with distinctive earlier arrivals and tailing effects, likely due to the physicochemical heterogeneities, i.e. the repulsive interactions and/or the macro-pores originating from local heterogeneities. The results imply that colloids can increase the Sr transport as a barrier of Sr sorption onto sediments herein, apart from often being carriers of sored radionuclides in aqueous phase. From a modelling perspective, the findings show that the established CTRW model is valid for quantifying the non-Fickian and promoted transport of Sr with colloids.


Assuntos
Coloides/química , Resíduos Radioativos/análise , Eliminação de Resíduos/métodos , Poluentes Radioativos do Solo/análise , Estrôncio/análise , Poluentes Radioativos da Água/análise , Radioisótopos/análise
4.
Environ Pollut ; 253: 278-287, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323610

RESUMO

The intensive use of Cu-based pesticides in agriculture could have an unintended impact on the ecosystems and human health via different exposure pathways. This paper presents the results of experiments involving colloidal stability, aggregation, and dissolution of Cu2O commercial pesticide under various environmental conditions in view of ecological implications. The investigated pesticide contains ∼750 g kg-1 Cu (75% weight of product), Cu2O particles with sizes < 1 µm, and nominal size fraction of Cu2O nanoparticles. The co-presence of Ca2+ (20 mM) and humic acid (HA, 15 mg L-1) significantly modulates (p < 0.001) the colloidal stability and mobility of particles. The dissolution of Cu at pH 5.5 was about 85%, 90%, and 75% weight more than the dissolution of Cu at pH 7.0, pH 8.5, and pH 7.0 and pH 8.5 combined, respectively in all dispersions. However, increasing HA content from 0 to 15 mg L-1 reduced the dissolution of Cu by 56%, 50%, and 40% weight at pH 5.5, 7.0, and 8.5, respectively. Thus, pH below 7.0 is a critical factor to control the dissolution and bioavailability of Cu that may pose ecotoxicity and environmental pollution, whereas pH above 7.0 and the presence of HA attenuate the pH effect. These findings provide insight into how the potential mobility and bioavailability of Cu is modulated by the water chemistry under various environmental scenarios and media.


Assuntos
Coloides/química , Cobre/toxicidade , Praguicidas/toxicidade , Agricultura , Ecologia , Substâncias Húmicas/análise , Nanopartículas
5.
Environ Sci Pollut Res Int ; 26(24): 25235-25246, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31256394

RESUMO

We explored the effect of the presence or absence of humic acid (HA) on the sorption behaviour of Sr onto soil. We examined three different experimental cases for Sr sorption: (1) sorption in the presence of only colloidal HA, (2) sorption in the presence of only soil and (3) sorption in the presence of both colloidal HA and soil (HS). A batch technique was used to study the influencing factors, including the amount of colloidal HA, solid content, pH, initial concentration of Sr and contact time. The experiments showed that the influencing factors significantly affected the sorption process. For example, in the case of soil and HS, the sorption percentage increased rapidly with increasing solid content at m/V < 20 g/L, changing from 8.35% and 37.54% to 49.09% and 77.03%, respectively. Moreover, scanning electron microscopy and Fourier transform infrared spectroscopy were used to characterize samples. The kinetics and isotherms of Sr were best described by the pseudo-second-order and Langmuir models, which indicated that the process was controlled by chemisorption and uniform monolayer sorption with constant energy on the outer surface. These findings provide valuable information for predicting strontium migration in radioactive waste disposal sites.


Assuntos
Coloides/química , Substâncias Húmicas , Resíduos Radioativos/análise , Poluentes do Solo/química , Estrôncio/química , Instalações de Eliminação de Resíduos , Adsorção , Geologia , Cinética , Radioatividade , Solo/química , Poluentes do Solo/análise , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Int J Nanomedicine ; 14: 4961-4974, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31308666

RESUMO

Background: Lipid polymer hybrid nanoparticles (LPHNPs) for the controlled delivery of hydrophilic doxorubicin hydrochloride (DOX.HCl) and lipophilic DOX base have been fabricated by the single step modified nanoprecipitation method. Materials and methods: Poly (D, L-lactide-co-glicolide) (PLGA), lecithin, and 1,2-distearoyl-Sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000 (DSPE-PEG 2000) were selected as structural components. Results: The mean particle size was 173-208 nm, with an encapsulation efficiency of 17.8±1.9 to 43.8±4.4% and 40.3±0.6 to 59. 8±1.4% for DOX.HCl and DOX base, respectively. The drug release profile was in the range 33-57% in 24 hours and followed the Higuchi model (R2=0.9867-0.9450) and Fickian diffusion (n<0.5). However, the release of DOX base was slower than DOX.HCl. The in vitro cytotoxicity studies and confocal imaging showed safety, good biocompatibility, and a higher degree of particle internalization. The higher internalization of DOX base was attributed to higher permeability of lipophilic component and better hydrophobic interaction of particles with cell membranes. Compared to the free DOX, the DOX.HCl and DOX base loaded LPHNPs showed higher antiproliferation effects in MDA-MB231 and PC3 cells. Conclusion: Therefore, LPHNPs have provided a potential drug delivery strategy for safe, controlled delivery of both hydrophilic and lipophilic form of DOX in cancer cells.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Doxorrubicina/uso terapêutico , Interações Hidrofóbicas e Hidrofílicas , Lipídeos/química , Nanopartículas/química , Polímeros/química , Varredura Diferencial de Calorimetria , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Coloides/química , Doxorrubicina/farmacologia , Liberação Controlada de Fármacos , Feminino , Humanos , Cinética , Nanopartículas/ultraestrutura , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática
7.
J Chem Phys ; 151(2): 024107, 2019 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-31301717

RESUMO

It is intuitive that the diffusivity of an isolated particle differs from those in a monodisperse suspension, in which hydrodynamic interactions between the particles are operative. Batchelor [J. Fluid Mech. 74, 1-29 (1976) and J. Fluid Mech. 131, 155-175 (1983)] calculated how hydrodynamic interactions influenced the diffusivity of a dilute suspension of spherical particles, and Russel et al. [Colloidal Dispersions (Cambridge University Press, 1991)] and Brady [J. Fluid Mech. 272, 109-134 (1994)] treated nondilute (higher particle volume fraction) suspensions. Although most particles lack perfect sphericity, little is known about the effects of hydrodynamic interactions on the diffusivity of spheroidal particles, which are the simplest shapes that can be used to model anisotropic particles. Here, we calculate the effects of hydrodynamic interactions on the translational and rotational diffusivities of spheroidal particles of arbitrary aspect ratio in dilute monodisperse suspensions. We find that the translational and rotational diffusivities of prolate spheroids are more sensitive to eccentricity than for oblate spheroids. The origin of the hydrodynamic anisotropy is that found in the stresslet field for the induced-dipole interaction. However, in the dilute limit, the effects of anisotropy are at the level of a few percent. These effects have influence on a vast range of settings, from partially frozen colloidal suspensions to the dynamics of cytoplasm.


Assuntos
Difusão , Hidrodinâmica , Coloides/química , Tamanho da Partícula , Propriedades de Superfície , Suspensões/química
8.
Int J Nanomedicine ; 14: 4367-4381, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354266

RESUMO

Purpose: Polyethylenimine (PEI) has been widely used as a versatile template to develop multifunctional nanosystems for disease diagnosis and treatment. In this study, we manufactured iodine-131 (131I)-labeled PEI-entrapped gold nanoparticles (Au PENPs) as a novel nanoprobe for single-photon emission computed tomography/computed tomography (SPECT/CT) imaging and radionuclide therapy. Materials and methods: PEI was PEGylated and sequentially conjugated with Buthus martensii Karsch chlorotoxin (BmK CT, a tumor-specific ligand which can selectively bind to MMP2), 3-(4'-hydroxyphenyl)propionic acid-OSu (HPAO), and fluorescein isothiocyanate to form the multifunctional PEI template for entrapment of Au NPs. Then, the PEI surface was radiolabeled with 131I via HPAO to produce the novel nanoprobe (BmK CT-Au PENPs-131I). Results: The synthesized multifunctional Au PENPs before and after 131I radiolabeling were well-characterized as follows: structure, X-ray attenuation coefficient, colloid stability, cytocompatibility, and radiochemical stability in vitro. Furthermore, BmK CT-Au PENPs-131I were suitable for targeted SPECT/CT imaging and radionuclide therapy of tumor cells in vitro and in a xenograft tumor model in vivo. Conclusion: The developed multifunctional Au PENPs are a promising theranostic platform for targeted imaging and treatment of different MMP2-overexpressing tumors.


Assuntos
Ouro/química , Radioisótopos do Iodo/química , Nanopartículas Metálicas/química , Polietilenoimina/química , Compostos Radiofarmacêuticos/uso terapêutico , Tomografia Computadorizada de Emissão de Fóton Único , Tomografia Computadorizada por Raios X , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Coloides/química , Glioma/patologia , Glioma/radioterapia , Humanos , Nanopartículas Metálicas/ultraestrutura , Camundongos Endogâmicos BALB C , Camundongos Nus , Especificidade de Órgãos , Tamanho da Partícula , Propionatos/química , Venenos de Escorpião/toxicidade
9.
Environ Sci Pollut Res Int ; 26(23): 24088-24098, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31228064

RESUMO

Colloidal particles in runoff could play an important role in phosphorus (P) transfer from sloped farmland to waterbodies. We investigated the distribution of P in different-size particles from a purple soil and colloidal phosphorus (CP) loss in runoff and sediment from sloped farmland in south-western China. The profile distribution of P showed obvious surface accumulation. The risk of P loss in topsoil was greater than those of the other soil layers on sloping farmland of purple soil. The concentration of soil particles of < 0.002 mm in purple soil profiles was low, but the total phosphorus (TP) and available phosphorus (AP) concentrations of soil particles of < 0.002 mm were high. During a rainfall event, CP loss is significantly power function related to the runoff yield rate, and is linearly related to the sediment yield rate. The majority of P in runoff was CP. The total loss of CP in runoff was 139.52 g ha-1, in which surface runoff accounted for 64.3%. CP loss can be controlled by controlling runoff from sloping farmland, especially surface runoff. Our results suggest that CP loss should be valued in the process of nutrient loss, as well as CP transfer should be given greater consideration in the mechanistic studies of the P transfer process.


Assuntos
Fósforo/análise , Solo/química , China , Coloides/química , Fazendas , Sedimentos Geológicos , Tamanho da Partícula , Chuva
10.
Carbohydr Polym ; 219: 423-430, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31151543

RESUMO

Colloidal polyaniline dispersions stabilized with biocompatible polysaccharides, sodium hyaluronate and chitosan (both with two different molecular weights), were successfully formulated. The colloids were characterized by UV-vis spectra, particle-size distributions and morphology, as well as by their biological properties in terms of cytotoxicity and antibacterial activity. Colloids containing both chitosan and hyaluronate showed only mild cytotoxicities, which were mainly governed by the concentration of conducting polyaniline in the colloid. Antibacterial activity of the samples, however, depended both on the type of polysaccharide and the ratio between the stabilizer and polyaniline mass. The colloid synthetized using 0.2 M aniline hydrochloride, 0.1 M ammonium persulfate, and 1 wt.% sodium hyaluronate of molecular weight of 1.8-2.1 × 106 exhibited the highest antibacterial activity against both gram positive and gram negative bacteria. This formulation, therefore, allowed for the formation of potentially stimuli-responsive antibacterial colloidal particles with low cytotoxicity.


Assuntos
Compostos de Anilina , Antibacterianos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Quitosana/química , Coloides , Ácido Hialurônico/química , Compostos de Anilina/química , Compostos de Anilina/farmacologia , Animais , Coloides/química , Coloides/farmacologia , Escherichia coli/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Nanocompostos/química , Staphylococcus aureus/efeitos dos fármacos
11.
Environ Pollut ; 251: 921-929, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31234258

RESUMO

The fast-growing production and application of carbon nanotube (CNT) materials in a variety of industrial products inevitably lead to their release to wastewater and surface water. CNT would experience oxidization in wastewater treatment plant due to the presence of large amount of disinfectants, such as H2O2 and O3, which in turn affects the environmental fates and risks of CNT. In this study, oxidized CNT materials (O-CNTs) were prepared by treating CNT with H2O2/UV and O3 (denoting as H2O2-CNT and O3-CNT, respectively). A variety of characterizations indicated that oxygen containing groups were generated on CNT surface upon the oxidation, and the O/C ratio increased in the order of pristine CNT < H2O2-CNT < O3-CNT. In the presence of Na+, K+ and Mg2+, the O-CNTs displayed better colloidal stability than the pristine CNT, and the stability increased with the oxidation degree (indicated by O/C ratio). This could be explained by the more negative surface charge and stronger hydrophilicity of the O-CNTs. Unexpectedly, in the presence of Ca2+, the most oxidized O3-CNT exhibited the poorest colloidal stability. The abundant carboxyl groups in O3-CNT provided effective binding sites for cation bridging effect through Ca2+ and led to stronger aggregation. Increasing pH was more favorable to disperse CNTs (both O-CNT and pristine CNT) in the presence of Na+, but much less effective in inhibiting the aggregation of O3-CNT in presence of Ca2+. This could be explained by the stronger cation bridging effect due to enhanced deprotonation the -COOH groups at higher pH conditions. The calculated Hamaker constants of the CNTs decreased with the oxidation degree, implying that there was lower van der Waals force between the O-CNTs. The Derjaguin-Landau-Verwey-Overbeek (DLVO) calculation confirmed that O-CNTs had to overcome higher energy barrier and thus showed better colloidal stability than the pristine CNT in the presence of Na+.


Assuntos
Coloides/química , Peróxido de Hidrogênio/química , Nanotubos de Carbono/química , Ozônio/química , Interações Hidrofóbicas e Hidrofílicas , Magnésio/química , Oxirredução , Potássio/química , Sódio/química , Águas Residuárias/química , Água/química
12.
Phys Chem Chem Phys ; 21(27): 15142-15150, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31243413

RESUMO

Improvement of pain management strategies after arthroscopic surgery by multimodal analgesia may include the use of long-acting amide local anesthetics. Among these anesthetics, the low molecular weight local anesthetic agent bupivacaine (BUP) is attractive for use in postoperative pain management. However, it has a relatively short duration of action and imposes a higher risk of systemic toxicity at relatively large bolus doses. Bupivacaine encapsulation in lipid-based delivery systems is an attractive strategy for prolonging its local anaesthetic effect and reducing the associated undesirable systemic side effects. Here, we discuss the potential development of liquid crystalline nanocarriers for delivering BUP by using a binary lipid mixture of citrem and soy phosphatidylcholine (SPC) at different weight ratios. The produced safe-by-design family of citrem/SPC nanoparticles is attractive for use in the development of nanocarriers owing to the previously reported hemocompatibility. BUP encapsulation efficiency (EE), depending on the lipid composition, was in the range of 65-77%. In this study, nanoparticle tracking analysis (NTA) and synchrotron small-angle X-ray scattering (SAXS) were employed to gain insight into the effect of BUP solubilization and lipid composition on the size and structural characteristics of the produced citrem/SPC nanodispersions. BUP loading led to a slight change in the mean sizes (diameters) and size distributions of citrem/SPC nanoparticles. However, we found that BUP accommodation into the self-assembled interiors of nanoparticles, triggers significant structural alterations in BUP concentration- and lipid composition-dependent manners, which involve vesicle-cubosome and vesicle-hexosome transitions. The structural tunability of citrem/SPC nanoparticles and the implications for potential applications in intra-articular BUP delivery are discussed.


Assuntos
Bupivacaína/química , Bupivacaína/metabolismo , Coloides/química , Nanopartículas/química , Anestésicos Locais/administração & dosagem , Anestésicos Locais/química , Anestésicos Locais/metabolismo , Bupivacaína/administração & dosagem , Sistemas de Liberação de Medicamentos , Solubilidade
13.
Opt Express ; 27(11): 16184-16194, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31163802

RESUMO

Double-nanoholes fabricated by colloidal lithography were used for trapping single colloidal particles and single proteins. A gap separation of 60 nm between the cusps of the double-nanohole was achieved in a gold film of 70 nm thickness sputter coated onglass. The cusp separation was reduced steadily down to 10 nm by plasma etching the colloidal particles prior to sputter coating. Scanning electron microscopy was used to locate a particular double-nanohole and it was registered for later microscopy experiments. 30 nm polystyrene particles, the rubisco protein and bovine serum albumin were trapped using a laser focused through the aperture. Compared to other methods that require top-down nanofabrication, this approach is inexpensive and produces high-quality samples.


Assuntos
Técnicas Biossensoriais , Coloides/química , Nanopartículas/química , Nanotecnologia/métodos , Ribulose-Bifosfato Carboxilase/química , Soroalbumina Bovina/química , Ouro , Microscopia Eletrônica de Varredura , Pinças Ópticas , Poliestirenos/química
14.
Int J Nanomedicine ; 14: 3629-3644, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31190816

RESUMO

Background: A very common and simple method (known as the blending method) to formulate drug delivery systems with required properties is to physically mix amphiphilic block copolymers with different hydrophobicity. In addition to its simplicity, this blending strategy could help avoid the time and effort involved in the synthesis of block copolymers with the desired structure required for specific drug formulations. Purpose: We used the blending strategy to design a system that could overcome the problem of high hydrophobicity and be a good candidate for drug product development using PEG-PLA-PEG triblock copolymers. Methods: Two types of PEG-PLA-PEG triblock copolymers with similar (long) PLA molecular weights (MWs) and different PEG MWs were synthesized. The micellar formulations were prepared by blending the two block copolymers in various ratios. The size and stability of the blending systems were subsequently investigated to optimize the formulations for further studies. The loading properties of doxorubicin or paclitaxel into the optimized blending system were compared to that in mono systems (systems composed of only a single type of triblock copolymer). In vitro and in vivo anti-cancer effects of the preparations were evaluated to assess the use of the blending system as an optimal nanomedicine platform for insoluble anticancer agents. Results: The blending system (B20 system) with an optimized ratio of the triblock copolymers overcame the drawbacks of mono systems. Drug uptake from the drug-loaded B20 system and its anticancer effects against KB cells were superior compared to those of free drugs (doxorubicin hydrochloride and free paclitaxel). In particular, doxorubicin-loaded B20 resulted in extensive doxorubicin accumulation in tumor tissues and significantly higher in vivo anti-cancer effects compared to free doxorubicin. Conclusion: The blending system reported here could be a potential nanoplatform for drug delivery due to its simplicity and efficiency for pharmaceutical application.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Tamanho da Partícula , Polímeros/química , Animais , Antineoplásicos/farmacologia , Coloides/química , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Humanos , Células KB , Camundongos Endogâmicos BALB C , Camundongos Nus , Micelas , Paclitaxel/farmacologia , Poliésteres/química , Polietilenoglicóis/química , Solubilidade , Distribuição Tecidual/efeitos dos fármacos
15.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1122-1123: 83-89, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31173996

RESUMO

For magnetic control of cells for biomedical applications such as targeting of immune cells to tumors, cells must be magnetizable. For that, cells are incubated with superparamagnetic iron oxide nanoparticles (SPIONs) to take them up and thus become magnetizable. When using adherent cells, non-ingested SPIONs can be easily removed by rinsing of the particles regardless of their colloidal stability in cell culture medium. However, if suspension cells such as T cells are to be loaded with SPIONs, established methods to separate excess nanoparticles from cells are based on physicochemical parameters such as density, size or magnetizability. Thus, colloidal stability of the particles is of great importance, since only colloidally stable SPIONs can be completely separated from the cells due to their physicochemical differences. Aggregates of colloidally meta- or unstable particles cannot, however, be separated from cells due to their overlapping sizes and densities. Thus, development of an alternative method for the separation of nanoparticle aggregates from suspension cells is urgently needed. Here, we present an affinity chromatographic separation method based on immunohistochemical properties of the respective cells. A desthiobiotinylated antibody against a cellular surface antigen (here CD90.2 receptor on EL4 T cells) is immobilized on a streptavidin agarose column optimized for cell purification. Subsequently the column is loaded with the particle/cell suspension so that the cells bind to the column. After removing the particles by washing, the cells can be gently eluted with biotin solution under physiological conditions. This allows >95% of the excess iron concentration to be removed while maintaining cell viability.


Assuntos
Cromatografia de Afinidade/métodos , Separação Imunomagnética/métodos , Nanopartículas de Magnetita/química , Animais , Anticorpos/metabolismo , Biotina/química , Linhagem Celular , Sobrevivência Celular/fisiologia , Coloides/química , Camundongos , Estreptavidina/química
16.
Food Chem ; 295: 548-555, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174794

RESUMO

The retrogradation behaviors and molecular structures of lotus seed starch (LS) combined with different hydrocolloids, chitosan (CS), guar gum (GG) and xanthan (XN), were investigated. Following an autoclave treatment, the storage modulus (G') value of LS-CS increased more rapidly than LS alone, indicating an increase in starch retrogradation. This might result from intermolecular interactions, increased ordered structure, decreased weight-average molecular weight (Mw) and greater leached amylose content in LS-CS system. The LS-GG and particularly LS-XN blends showed the opposite trend. The much greater Mw of LS-XN was mainly attributed to the lower retrogradation rate. The enwrapping effect of GG or XN on LS, as observed by confocal laser scanning microscopy, might retard their retrogradation by limiting the granules' swelling and the amylose leaching. Overall, the changes in the interaction force, ordered structure, Mw, leached amylose and microstructure were related to retrogradation behaviors of LS-hydrocolloid blends following an autoclave treatment.


Assuntos
Coloides/química , Lotus/metabolismo , Amido/química , Amilose/química , Quitosana/análise , Galactanos/análise , Temperatura Alta , Mananas/análise , Microscopia de Força Atômica , Peso Molecular , Gomas Vegetais/análise , Polissacarídeos Bacterianos/análise , Reologia , Sementes/metabolismo
17.
J Chromatogr A ; 1599: 203-214, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31047657

RESUMO

Colloidal iron(III) oxyhydroxides (FeOx) are important reactive adsorbents in nature. This study was set up to determine the size of environmentally relevant FeOx colloids with new methods, i.e. Flow Field Flow Fractionation (FlFFF-UV-ICP-MS) and single-particle ICP-MS/MS (sp-ICP-MS) and to compare these with standard approaches, i.e. dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), microscopy (TEM), membrane filtration, centrifugation and dialysis. Seven synthetic nano- and submicron FeOx with different mineralogy and coating were prepared and two soil solutions were included. The FlFFF was optimized for Fe recovery, yielding 70-90%. The FlFFF determines particle size with high resolution in a 1 mM NH4HCO3 (pH 8.3) background and can detect Fe-NOM complexes <5 nm and organo-mineral FeOx particles ranging 5-300 nm. The sp-ICP-MS method had a size detection limit for FeOx of about 32-47 nm. The distribution of hydrodynamic diameters of goethite particles detected with FlFFF, NTA and DLS were similar but the values were twice as large as the Fe cores of particles detected with sp-ICP-MS and TEM. Conventional fractionation by centrifugation and dialysis generally yielded similar fractions as FlFFF but membrane filtration overestimated the large size fractions. Particles formed from Fe(II) oxidation in the presence of NOM showed strikingly smaller organo-mineral Fe-Ox colloids as the NOM/Fe ratio increased. The soil solution obtained with centrifugation of an acid peat was dominated by small (<30 nm) Fe-OM complexes and organo-mineral FeOx colloids whereas that of a mineral pH neutral soil mainly contains larger (30-200 nm) Fe-rich particles. The FlFFF-UV-ICP-MS is recommended for environmental studies of colloidal FeOx since it has a wide size detection range, it fractionates in an environmentally relevant background (1 mM NH4HCO3) and it has acceptable element recoveries.


Assuntos
Técnicas de Química Analítica/métodos , Coloides/análise , Compostos Férricos/análise , Fracionamento por Campo e Fluxo , Minerais/análise , Espectrometria de Massas em Tandem , Técnicas de Química Analítica/normas , Coloides/química , Difusão Dinâmica da Luz , Compostos de Ferro/análise , Compostos de Ferro/química , Minerais/química , Nanopartículas/análise , Tamanho da Partícula , Solo/química , Análise Espectral
18.
Chemosphere ; 231: 405-414, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31146132

RESUMO

The release of uranyl from uranium tailing sites is a widely concerned environmental issue, with limited investigations on the effect of coexistence of various colloids. Gibbsite colloids extensively exist, together with ubiquitous humic substances, in uranium polluted waters at tailing sites, due to high concentration of dissolved Al in acid mine drainage. In this context, we investigated the co-transport of U(VI), gibbsite colloids and humic acid (HA) as a function of pH and ionic strength at a U(VI) concentration (5.0 × 10-5 M) relevant within mine tailings and related waste. It was found that, owing to electrostatic attraction, gibbsite colloids and HA associated with each other and transported simultaneously regardless of U(VI) presence. Besides the impact of pH and ionic strength, whether gibbsite colloids facilitated U(VI) transport depended on HA concentration. Gibbsite colloids impeded U(VI) transport at relatively low HA concentration (≤5 mg L-1), because associated colloids loaded with U(VI) were positively charged which favored colloid retention on negatively charged quartz sand in the column. U(VI) together with gibbsite colloids and low concentration HA was completely blocked at natural pH and/or high ionic strength. At relatively high HA concentration (20 mg L-1), however, the associated colloids showed negative zeta potential which facilitated U(VI) transport because of repulsion between negatively charged colloids and quartz sand. Meanwhile, high concentration of HA dramatically accelerated the transport of gibbsite colloids. These results implied that gibbsite colloids might imped U(VI) migration at uranium tailing sites unless the aquifers are enriched with abundant humic substances.


Assuntos
Coloides/química , Substâncias Húmicas/análise , Modelos Químicos , Urânio/química , Poluentes Radioativos da Água/química , Adsorção , Água Subterrânea/química , Concentração Osmolar , Porosidade , Quartzo , Dióxido de Silício , Simportadores , Urânio/análise , Água
19.
J Zhejiang Univ Sci B ; 20(4): 343-354, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30932379

RESUMO

Rice stripe virus (RSV) causes dramatic losses in rice production worldwide. In this study, two monoclonal antibodies (MAbs) 16E6 and 11C1 against RSV and a colloidal gold-based immunochromatographic strip were developed for specific, sensitive, and rapid detection of RSV in rice plant and planthopper samples. The MAb 16E6 was conjugated with colloidal gold and the MAb 11C1 was coated on the test line of the nitrocellulose membrane of the test strip. The specificity of the test strip was confirmed by a positive reaction to RSV-infected rice plants and small brown planthopper (SBPH), and negative reactions to five other rice viruses, healthy rice plants, four other vectors of five rice viruses, and non-viruliferous SBPH. Sensitivity analyses showed that the test strip could detect the virus in RSV-infected rice plant tissue crude extracts diluted to 1:20 480 (w/v, g/mL), and in individual viruliferous SBPH homogenate diluted to 1:2560 (individual SPBH/µL). The validity of the developed strip was further confirmed by tests using field-collected rice and SBPH samples. This newly developed test strip is a low-cost, fast, and easy-to-use tool for on-site detection of RSV infection during field epidemiological studies and paddy field surveys, and thus can benefit decision-making for RSV management in the field.


Assuntos
Cromatografia de Afinidade/métodos , Doenças das Plantas/virologia , Tenuivirus/isolamento & purificação , Anticorpos Monoclonais/química , China , Colódio/química , Coloides/química , Coloide de Ouro/química , Teste de Materiais , Membranas Artificiais , Oryza/virologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Especificidade da Espécie
20.
Mater Sci Eng C Mater Biol Appl ; 101: 204-216, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31029313

RESUMO

We synthesized silver nanoparticles using thirty Chinese plant extracts via a green synthetic strategy. UV-visible spectra showed that the silver nanoparticles have an absorbance at 450 nm. Among the thirty extracts, seven extracts (Cratoxylum formosum, Phoebe lanceolata, Scurrula parasitica, Ceratostigma minus, Mucuna birdwoodiana, Myrsine africana and Lindera strychnifolia) exhibited the successful synthesis of silver nanoparticles. These seven extracts showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power than the other extracts. The silver nanoparticles synthesized using these seven extracts were mostly spherical with high colloidal stability. The cytotoxicity of these seven silver nanoparticle samples on human lung cancer cells (A549) was clearly higher than that of the extracts alone. Furthermore, the cytotoxicity was affected by the presence or absence of fetal bovine serum. Moreover, the cytotoxicity of the silver nanoparticles synthesized with Cratoxylum formosum and Mucuna birdwoodiana extracts resulted in apoptotic cell death in A549 cells. The wound healing activity observed by the cell scratch method on mouse fibroblast cells (NIH3T3) suggested that the Lindera strychnifolia extract produced silver nanoparticles with decent activity. These results provide ample and systematic information for researchers on the green synthesis of silver nanoparticles using plant extracts.


Assuntos
Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Química Verde/métodos , Nanopartículas Metálicas/química , Extratos Vegetais/farmacologia , Prata/farmacologia , Cicatrização/efeitos dos fármacos , Células A549 , Animais , Compostos de Bifenilo/química , Coloides/química , Depuradores de Radicais Livres/química , Humanos , Hidrodinâmica , Nanopartículas Metálicas/ultraestrutura , Camundongos , Células NIH 3T3 , Oxirredução , Tamanho da Partícula , Picratos/química , Espectrofotometria Ultravioleta , Coloração e Rotulagem , Eletricidade Estática
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