Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 10.192
Filtrar
1.
Pharm Res ; 37(10): 193, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32914377

RESUMO

PURPOSE: The incidence of breast cancer worldwide has been on the rise since the late 1970s, and it has become a common tumor that threatens women's health. Aminoglutethimide (AG) is a common treatment of breast cancer. However, current treatments require frequent dosing that results in unstable plasma concentration and low bioavailability, risking serious adverse reactions. Our goal was to develop a molecularly imprinted polymer (MIP) based delivery system to control the release of AG and demonstrate the availability of this drug delivery system (DDS), which was doped with carbon nanotube with aid of metal-organic gel. METHODS: Preparation of MIP was optimized by key factors including composition of formula, ratio of monomers and drug loading concentration. RESULTS: By using multi-walled carbon nanotubes (MWCNT) and metal-organic gels (MOGs), MIP doubled the specific surface area, pore volume tripled and the IF was 1.6 times than the reference. Compared with commercial tablets, the relative bioavailability was 143.3% and a more stable release appeared. CONCLUSIONS: The results highlight the influence of MWCNT and MOGs on MIP, which has great potential as a DDS.


Assuntos
Aminoglutetimida/química , Antineoplásicos Hormonais/química , Complexos de Coordenação/química , Sistemas de Liberação de Medicamentos/métodos , Nanotubos de Carbono/química , Aminoglutetimida/administração & dosagem , Aminoglutetimida/farmacocinética , Animais , Antineoplásicos Hormonais/administração & dosagem , Antineoplásicos Hormonais/farmacocinética , Complexos de Coordenação/administração & dosagem , Compostos Férricos/química , Géis/administração & dosagem , Géis/química , Humanos , Células MCF-7 , Masculino , Impressão Molecular/métodos , Ratos , Ácidos Tricarboxílicos/química
2.
Chemosphere ; 258: 127288, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947659

RESUMO

The discharge of toxic elements from tailings soils in the aquatic environments occurs chiefly in the presence of indigenous bacteria. The biotic components may interact in the opposite direction, leading to the formation of a passivation layer, which can inhibit the solubility of the elements. In this work, the influence of jarosite on the bio-immobilization of toxic elements was studied by native bacteria. In batch experiments, the bio-immobilization of heavy metals by an inhibitory layer was examined in the different aquatic media using pure cultures of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. A variety of analyses also investigated the mechanisms of metals bio-immobilization. Among different tests, the highest metal solubility yielded 99% Mn, 91% Cr, 95% Fe, and 78% Cu using A. ferrooxidans in 9KFe medium after ten days. After 22 days, these percentages decreased down to 30% Mn and about 20% Cr, Fe, and Cu, likely due to metal immobilization by biogenic jarosite. The formation of jarosite was confirmed by an electron probe micro-analyzer (EPMA), X-ray diffraction (XRD), and scanning electron microscope (SEM). The mechanisms of metal bio-immobilization by biogenic jarosite from tailings soil confirmed three main steps: 1) the dissolution of metal sulfides in the presence of Acidithiobacillus bacteria; 2) the nucleation of jarosite on the surface of sulfide minerals; 3) the co-precipitation of dissolved elements with jarosite during the bio-immobilization process, demonstrated by a structural study for jarosite. Covering the surface of soils by the jarosite provided a stable compound in the acidic environment of mine-waste.


Assuntos
Compostos Férricos/química , Substâncias Perigosas/análise , Sulfatos/química , Acidithiobacillus , Acidithiobacillus thiooxidans , Bactérias , Substâncias Perigosas/toxicidade , Metais Pesados , Minerais , Solubilidade , Sulfetos/química , Difração de Raios X
3.
Int J Nanomedicine ; 15: 4811-4824, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32753867

RESUMO

Purpose: Magnetic resonance imaging (MRI) contrast agents are pharmaceuticals that enable a better visualization of internal body structures. In this study, we present the synthesis, MRI signal enhancement capabilities, in vitro as well as in vivo cytotoxicity results of gold-coated iron oxide nanoparticles (Fe3O4@AuNPs) as potential contrast agents. Methods: Fe3O4@AuNPs were obtained by synthesizing iron oxide nanoparticles and gradually coating them with gold. The obtained Fe3O4@AuNPs were characterized by spectroscopies, transmission electron microscopy (TEM) and energy dispersive X-ray diffraction. The effect of the nanoparticles on the MRI signal was tested using a 7T Bruker PharmaScan system. Cytotoxicity tests were made in vitro on Fe3O4@AuNP-treated retinal pigment epithelium cells by WST-1 tests and in vivo by following histopathological changes in rats after injection of Fe3O4@AuNPs. Results: Stable Fe3O4@AuNPs were successfully prepared following a simple and fast protocol (<1h worktime) and identified using TEM. The cytotoxicity tests on cells have shown biocompatibility of Fe3O4@AuNPs at small concentrations of Fe (<1.95×10-8 mg/cell). Whereas, at higher Fe concentrations (eg 7.5×10-8 mg/cell), cell viability decreased to 80.88±5.03%, showing a mild cytotoxic effect. MRI tests on rats showed an optimal Fe3O4@AuNPs concentration of 6mg/100g body weight to obtain high-quality images. The histopathological studies revealed significant transient inflammatory responses in the time range from 2 hours to 14 days after injection and focal cellular alterations in several organs, with the lung being the most affected organ. These results were confirmed by hyperspectral microscopic imaging of the same, but unstained tissues. In most organs, the inflammatory responses and sublethal cellular damage appeared to be transitory, except for the kidneys, where the glomerular damage indicated progression towards glomerular sclerosis. Conclusion: The obtained stable, gold covered, iron oxide nanoparticles with reduced cytotoxicity, gave a negative T2 signal in the MRI, which makes them suitable for candidates as contrast agent in small animal MRI applications.


Assuntos
Meios de Contraste/química , Compostos Férricos/química , Ouro/química , Imagem por Ressonância Magnética , Nanopartículas Metálicas/química , Animais , Sobrevivência Celular , Endocitose , Inflamação/patologia , Masculino , Nanopartículas Metálicas/ultraestrutura , Ratos Wistar , Difração de Raios X
4.
Ecotoxicol Environ Saf ; 202: 110921, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800256

RESUMO

Jarosite is one of the iron oxyhydroxysulfate minerals that are commonly found in acid mine drainage (AMD) systems. In natural environments, phosphate and sulfate reducing bacteria (SRB) may be coupled to jarosite reduction and transformation. In this research, the effect of phosphate on jarosite reduction by SRB and the associated secondary mineral formation was studied using batch experiments. The results indicated that Fe3+ is mainly reduced by biogenic S2- in this experiment. The effect of PO43- on jarosite reduction by SRB involved not only a physico-chemical factor but also a microbial factor. Phosphate is an essential nutrient, which can support the activity of SRB. In the low PO43- treatment, the production of total Fe2+ was found to be slightly larger than that in the zero PO43- treatment. Sorption of PO43- effectively elevated jarosite stability via the formation of inner sphere complexes, which, therefore, inhibited the reductive dissolution of jarosite. At the end of the experiment, the amounts of total Fe2+ accumulation were determined to be 4.54 ± 0.17a mM, 4.66 ± 0.22a mM, 3.91 ± 0.04b mM and 2.51 ± 0.10c mM (p < 0.05) in the zero, low, medium and high PO43- treatments, respectively, following the order of low PO43- treatment > zero PO43- treatment > medium PO43- treatment > high PO43- treatment. PO43- loading modified the transformation pathways for the jarosite mineral, as well. In the zero PO43- treatment, the jarosite diffraction lines disappeared, and mackinawite dominated at the end of the experiment. Compared to PO43--free conditions, vivianite was found to become increasingly important at higher PO43- loading conditions. These findings indicate that PO43- loading can influence the broader biogeochemical functioning of AMD systems by impacting the reactivity and mineralization of jarosite mineral.


Assuntos
Bactérias/metabolismo , Compostos Férricos/química , Fosfatos/química , Sulfatos/química , Adsorção , Biodegradação Ambiental , Compostos Ferrosos , Ferro/química , Compostos de Ferro/química , Minerais , Mineração , Oxirredução
5.
J Chromatogr A ; 1627: 461382, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823094

RESUMO

A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid Ⅰ and Ⅱ. 3-Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support. The morphology and structure of adenine-coated magnetic carbon nanotubes was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The adsorption performance of the adenine-coated magnetic carbon nanotubes was evaluated via adsorption isotherms, the kinetics and selectivity tests. The adsorption capacity of the adenine-functionalized sorbent for aristolochic acid Ⅰ was determined to be 24.5 µg mg-1. By combining magnetic solid phase extraction with HPLC detection, a method was developed to enrich and detect aristolochic acids used in traditional Chinese medicine. A satisfactory recovery (92.7 - 97.5% for aristolochic acid Ⅰ and 92.6 - 99.4% for aristolochic acid Ⅱ) and an acceptable relative standard deviation (<4.0%) were obtained.


Assuntos
Adenina/química , Ácidos Aristolóquicos/isolamento & purificação , Fenômenos Magnéticos , Nanotubos de Carbono/química , Adsorção , Medicamentos de Ervas Chinesas/química , Compostos Férricos/síntese química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Nanocompostos/química , Nanotubos de Carbono/ultraestrutura , Concentração Osmolar , Reprodutibilidade dos Testes , Dióxido de Silício/síntese química , Dióxido de Silício/química , Extração em Fase Sólida , Temperatura , Difração de Raios X
6.
J Chromatogr A ; 1626: 461328, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797818

RESUMO

Ferric oxide/carbon (Fe2O3@C) was fabricated via direct carbonization of metal-organic framework of iron (MOF-235) under argon atmosphere. The magnetic Fe2O3 nanoparticles are evenly embedded in porous carbon matrix, while original morphology of MOF-235 was well-maintained. The synthesized Fe2O3@C was used as magnetic sorbent for extracting five benzoylurea insecticides (BUs). The materials exhibited excellent extraction performance, which benefited not only from the strong π-π interaction and hydrophobic interaction (π-conjugated system), but also to the abundant adsorption sites and flexible transport channel (the interconnected 3D porous structure). A three-factor-three-level Box-Behnken design (BBD) was selected to optimize three greatly influential parameters: amount of adsorbent (A), desorption time (B) and volume of desorption solvent (C) by response surface methodology. The established method coupled to HPLC-UV detection showed wide linearity with the range of 0.2-450 µg•L-1, relatively low limits of detection (0.05-0.10 µg•L-1) with the relative standard deviation (RSD) (n = 7) lower t than 5.47%. Moreover, the proposed method was successfully applied to analyze BUs in tea samples and investigate the removal effect of different washing on BUs residues from tea leaf. These results indicated that the synthesized Fe2O3@C is a promising adsorbent material for magnetic solid phase extraction of BUs at trace concentrations from tea samples.


Assuntos
Inseticidas/análise , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/química , Chá/química , Ureia/análise , Adsorção , Carbono/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Compostos Férricos/química , Inseticidas/isolamento & purificação , Inseticidas/normas , Limite de Detecção , Porosidade , Padrões de Referência , Extração em Fase Sólida , Espectrofotometria Ultravioleta , Chá/metabolismo , Ureia/análogos & derivados , Ureia/isolamento & purificação , Ureia/normas
7.
Int J Nanomedicine ; 15: 5165-5177, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32764943

RESUMO

Background: The integration of NIR photothermal therapy and chemotherapy is considered as a promising technique for future cancer therapy. Hollow Prussian nanospheres have attracted much attention due to excellent near-infrared photothermal conversion effect and drug-loading capability within an empty cavity. However, to date, the hollow Prussian nanospheres have been prepared by a complex procedure or in organic media, and their shell thickness and size cannot be controlled. Thus, a simple and controllable route is highly desirable to synthesize hollow Prussian nanospheres with controllable parameters. Materials and Methods: Here, in our designed synthesis route, the traditional FeCl3 precursor was replaced with Fe2O3 nanospheres, and then the Prussian blue (PB) nanoparticles were engineered into hollow-structured PB (HPB) nanospheres through an interface reaction, where the Fe2O3 colloidal template provides Fe3+ ions. The reaction mechanism and control factors of HPB nanospheres were systematically investigated. Both in vitro and in vivo biological effects of the as-synthesized HPB nanospheres were evaluated in detail. Results: Through systematical experiments, a solvent-mediated interface reaction mechanism was put forward, and the parameters of HPB nanospheres could be easily adjusted by growth time and template size under optimal water and ethanol ratio. The in vitro tests show the rapid and remarkable photothermal effects of the as-prepared HPB nanospheres under NIR laser irradiation (808 nm). Meanwhile, HPB nanospheres also demonstrated a high DOX loading capacity of 440 mg g-1 as a drug carrier, and the release of the drug can be regulated by the heat from PB shell under the exposure of an NIR laser. The in vivo experiments confirmed the outstanding performance of HPB nanospheres in photothermal/chemo-synergistic therapy of cancer. Conclusion: A solvent-mediated template route was developed to synthesize hollow Prussian blue (HPB) nanospheres in a simple and controllable way. The in vitro and in vivo results demonstrate the as-synthesized HPB nanospheres as a promising candidate due to their low toxicity and high efficiency for cancer therapy.


Assuntos
Portadores de Fármacos/química , Ferrocianetos/química , Nanosferas/química , Fototerapia/métodos , Terapia Combinada , Doxorrubicina/química , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Compostos Férricos/química , Humanos , Hipertermia Induzida
8.
Chemosphere ; 260: 127681, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32758785

RESUMO

In this work, magnetic separably barium ferrite nanomaterial (BaFeO) was synthesized via citrate acid assisted sol-gel combustion method. Subsequently, X-ray diffraction (XRD), scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were applied for its structural, morphological, and electromagnetic characterization. In addition, microwave (MW) absorption and thermal conversion test results indicated the BaFeO had electrothermal rather than magnetothermal conversion capacity. Meanwhile, the synthesized BaFeO showed satisfactory performance in both eliminating and mineralization of a typical triphenylmethane dye, brilliant green (BG), in MW-induced catalytic oxidation (MICO) process without extra oxidant addition. Besides, changes in element valence and content of BaFeO before and after MICO process investigated with XRD, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) showed its relatively stable properties. Furthermore, transition oxygen species involved in MICO process was deduced as lattice oxygen species. Then, the possible degradation pathway of BG was proposed as demethylation, open-loop of triphenylmethane, releasing one ring, formation of the benzene ring and the ultimate mineralization based on the degradation intermediates tentatively identified by gas chromatography mass spectrometry (GC/MS) and liquid chromatography mass spectrometry (LC/MS), respectively. Finally, ecotoxicity analysis by ecological structure activity relationships (ECOSAR) showed that both the acute and chronic toxicity of these intermediates were lower than that of parent BG. These findings are important regarding the development of efficient catalysts in MICO process for degradation of BG analogues in wastewater.


Assuntos
Compostos de Bário/química , Compostos Férricos/química , Nanoestruturas/química , Compostos de Amônio Quaternário/química , Catálise , Corantes/química , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Micro-Ondas , Espectroscopia Fotoeletrônica , Águas Residuárias , Difração de Raios X
9.
Ecotoxicol Environ Saf ; 204: 111097, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32784016

RESUMO

Iron (hydr)oxide-natural organic matter (NOM) colloids, the dominant components of soil, usually occur in varied circumstances and may affect Hg transport and fate in soil. This study aims to reveal the Hg binding to preformed composites rather than only focusing on Hg retention by iron (hydr)oxides in the presence of NOM. Ferrihydrite-humic acid (FH-HA) is chosen as a representative composite, and the effect of the complexation method and FH morphology on Hg binding to various composites is evaluated. Three types of composites are developed: a dense coprecipitated composite (p-d-f), a gel-like adsorbed composite (a-g-f) and a dense adsorbed (a-d-f) composite. Batch sorption and stirred-flow kinetic tests together with surface property analysis and modern spectral analyses are carried out to explore the binding behavior of Hg to the three composites and clarify the interactions in the ternary systems of FH-HA-Hg. The results show that the Hg sorption isotherms all fit well with the Langmuir model, and the maximum sorption capacities follow the order a-g-f> a-d-f > p-d-f, implying that the adsorbed composite is more favorable than the coprecipitated composite for Hg binding and a gel morphology is more beneficial than a dense morphology. The stirred-flow experiments show that the adsorbed composite has a small advantage in Hg sorption compared to the coprecipitated composite and that the gel-like composite can adsorb more Hg at a faster rate than the dense composite. Both FH and HA participate in Hg sorption, and FH-HA-Hg complexes are speculated to form. These findings are helpful to better understand the mobility and fate of Hg in soils, as well as the associated dynamic model for predicting Hg behavior in the environment where the iron (hydr) oxide-NOM composites are pre-existed.


Assuntos
Mercúrio/química , Adsorção , Coloides , Compostos Férricos/química , Substâncias Húmicas/análise , Ferro/análise , Cinética , Mercúrio/análise , Compostos Orgânicos/química , Óxidos/química , Solo/química , Propriedades de Superfície
10.
Ecotoxicol Environ Saf ; 202: 110893, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32615495

RESUMO

Leaching of the hazardous electric arc furnace (EAF) dust containing mainly zinc ferrite and zinc oxide, accompanied by minor concentrations of arsenic compounds, was investigated using sulfuric acid. In order to reach the maximum recovery of zinc, the leaching solution was adjusted to recover both iron and zinc at their maximum possible values. To obtain a high recovery value of zinc and iron, analyzed by AAS, the optimum leaching condition was found to be the temperature of 90 °C, the sulfuric acid concentration of 3 M, the particle size of 75 µm, the S/L ratio of 1:10 g/mL and the leaching time of 2 h. The percentages of the zinc and iron recovery under the optimum condition were ca. 98.6% and 99.1% respectively, which were verified by a confirmation test and were very close to the predicted values of 100% based on the optimized model, obtained through the software. From the thermodynamics' point of view, it has been found that Zn2+ is the predominant species (90%) under the leaching condition applied. Moreover, the predominant species of iron are FeSO4+, FeHSO42+, Fe(SO4)2- and Fe3+ in the magnitudes of 65.8%, 25.6%, 4.4% and 4.0%, respectively. According to the kinetic results, the controlling step in the leaching was the chemical reaction at the most of the operating temperatures and times. In order to purify the zinc solution for electrowinning, iron and arsenic were removed through the jarosite formation process as confirmed by the XRD results. The speciation of arsenic in the precipitated jarosite was explored by XPS. Finally, the low concentrations of arsenic (less than 0.1 ppm) and iron (less than 50 ppm) were determined by the ICP analysis.


Assuntos
Compostos Férricos/química , Metalurgia/métodos , Reciclagem , Sulfatos/química , Zinco/análise , Poeira/análise , Eletricidade , Ferro/química , Tamanho da Partícula , Ácidos Sulfúricos , Temperatura , Óxido de Zinco
11.
Ecotoxicol Environ Saf ; 202: 110898, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32652344

RESUMO

Recent research has shown that the complexation of metals-organics plays an important role in atmospheric particulate matter, whose health effects should be taken into account. This work investigates the interactions between catechols (CAs), i.e., 4-nitrocatechol (4NC) and 4-methylcatechol (4MC), and transition metals (i.e., Fe) in the aqueous phase dark reaction. The formation of Fe/CAs complexes and secondary organics products are analyzed by UV-Vis spectroscopy, stopped-flow spectroscopy, high-resolution mass spectrometry and Raman spectroscopy, while the insoluble particulate matter formed from the CAs/Fe mixtures are characterized by the FTIR, X-ray photoelectron spectroscopy (XPS) and thermogravimetric-quadrupole-mass spectrometry (TG-Q-MS). On the basis of the density functional theory (DFT) calculation and experimental results, the possible formation pathways for the complexes of Fe(III) with 4NC (a proxy for organics) are proposed. The Fe/CAs complexes and organics products perhaps have significant sources of light absorption which play an important role in influencing the intensity of atmospheric radiation and particulate phase photochemistry. Besides, the cytotoxicity is tested as a function of concentrations for CAs/Fe mixtures in BEAS-2B cells. Our results show that CAs/Fe mixtures have strong association with cytotoxicity, indicating the mixtures have potential influence to human health.


Assuntos
Catecóis/química , Compostos Férricos/química , Testes de Toxicidade , Atmosfera/química , Catecóis/toxicidade , Células Epiteliais , Compostos Férricos/toxicidade , Humanos , Espectrometria de Massas , Metais , Material Particulado , Análise Espectral , Água/química
12.
Nat Commun ; 11(1): 3637, 2020 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-32686685

RESUMO

We report a strategy to boost Fenton reaction triggered by an exogenous circularly polarized magnetic field (MF) to enhance ferroptosis-like cell-death mediated immune response, as well as endow a responsive MRI capability by using a hybrid core-shell vesicles (HCSVs). HCSVs are prepared by loading ascorbic acid (AA) in the core and poly(lactic-co-glycolic acid) shell incorporating iron oxide nanocubes (IONCs). MF triggers the release of AA, resulting in the increase of ferrous ions through the redox reaction between AA and IONCs. A significant tumor suppression is achieved by Fenton reaction-mediated ferroptosis-like cell-death. The oxidative stress induced by the Fenton reaction leads to the exposure of calreticulin on tumor cells, which leads to dendritic cells maturation and the infiltration of cytotoxic T lymphocytes in tumor. Furthermore, the depletion of ferric ions during treatment enables monitoring of the Fe reaction in MRI-R2* signal change. This strategy provides a perspective on ferroptosis-based immunotherapy.


Assuntos
Ferroptose/efeitos dos fármacos , Campos Magnéticos , Nanopartículas de Magnetita , Neoplasias/terapia , Animais , Ácido Ascórbico/farmacologia , Calreticulina/metabolismo , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos/métodos , Compostos Férricos/química , Imunoterapia/métodos , Imagem por Ressonância Magnética , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/uso terapêutico , Camundongos , Nanomedicina/métodos , Nanopartículas/química , Nanopartículas/uso terapêutico , Neoplasias/diagnóstico por imagem , Neoplasias/imunologia , Estresse Oxidativo , Linfócitos T Citotóxicos/metabolismo
13.
Food Chem ; 332: 127398, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32610260

RESUMO

Herein, a label-free and dual-readout immunochromatographic test strip (ITS) for the sensitive detection of Escherichia coli (E. coli) O157:H7 by taking advantages of the strong capture ability of Fe3O4@CuS nanostructures (NSs) towards bacteria and their ultrahigh photothermal effects (PTEs) was reported. Especially, without the customarily antibody (Ab)-labeled probe, Fe3O4@CuS NSs could be adsorbed onto the surfaces of bacteria to form Fe3O4@CuS-bacteria conjugates and then trapped by immobilized Abs on the test line (T-line), forming a characteristic yellow band. After direct immunoreactions, the PTEs of Fe3O4@CuS NSs endowed T-line to be irradiated by an 808 nm infrared light, obtaining satisfactory sensitivity and accuracy. Under optimal conditions, E. coli O157:H7, as low as 103 and 102 CFU/mL, could be monitored in colorimetric and photothermal modes. Additionally, E. coli O157:H7 was successfully detected in beef, chicken, milk and honey samples by this proposed platform with a recovery of 80-120%.


Assuntos
Cromatografia de Afinidade/métodos , Cobre/química , Escherichia coli O157/isolamento & purificação , Compostos Férricos/química , Microbiologia de Alimentos/métodos , Animais , Anticorpos Monoclonais/imunologia , Bovinos , Galinhas/microbiologia , Cromatografia de Afinidade/instrumentação , Escherichia coli O157/imunologia , Microbiologia de Alimentos/instrumentação , Mel/microbiologia , Limite de Detecção , Leite/microbiologia , Fitas Reagentes/química , Carne Vermelha/microbiologia
14.
Ecotoxicol Environ Saf ; 203: 110945, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32684517

RESUMO

The high-concentration wastewater produced in the industrial reverse osmosis (RO) process contains a large amount of refractory organic matters, which will have serious impacts on the natural environment and human health. Among them, contaminants can be transformed by humus-reducing bacteria based on humus. In this study, O3- assisted UV-Fenton method was applied as pretreatment. Biological activated carbon (BAC) technology in which humus-reducing bacteria were the dominant bacteria, enhanced by electron donor and Fe3+, was used to dispose of RO concentrate (ROC). The results showed that water treatment process combining oxidation with biological filtration had a positive effect on the removal of stubborn contaminants in ROC. The system was strengthened by adding electron donor and Fe3+, and the chemical oxygen demand (COD) removal efficiency was up to 80.1%. However, when the removal efficiency of UV254 absorbing pollutants reached optimal value (87.3%), that means only Fe3+ was added.


Assuntos
Carvão Vegetal/análise , Compostos Férricos/química , Substâncias Húmicas , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Análise da Demanda Biológica de Oxigênio , Filtração/métodos , Substâncias Húmicas/análise , Substâncias Húmicas/microbiologia , Hidrocarbonetos Halogenados/análise , Peróxido de Hidrogênio/química , Ferro/química , Osmose , Oxirredução , Ozônio/química , Raios Ultravioleta , Águas Residuárias/análise , Águas Residuárias/microbiologia
15.
Chemosphere ; 260: 127554, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688313

RESUMO

Estuarine sediments are often characterized by abundant iron oxides, organic matter, and anthropogenic nitrogen compounds (e.g., nitrate and nitrite). Anoxic dissimilatory iron reducing bacteria (e.g., Shewanella loihica) are ubiquitous in these environments where they can catalyze the reduction of Fe(III) (oxyhydr)oxides, thereby releasing aqueous Fe(II). The biologically produced Fe(II) can later reduce nitrite to form nitrous oxide. The effect on nitrite reduction by both biologically produced and artificially amended Fe(II) was examined experimentally. Ferrihydrite was reduced by Shewanella loihica in a batch reaction with an anoxic synthetic sea water medium. Some of the Fe(II) released by S. loihica adsorbed onto ferrihydrite, which was involved in the transformation of ferrihydrite to magnetite. In a second set of experiments with identical medium, no microorganism was present, instead, Fe(II) was amended. The amount of solid-bound Fe(II) in the experiments with bioproduced Fe(II) increased the rate of abiotic NO2- reduction with respect to that with synthetic Fe(II), yielding half-lives of 0.07 and 0.47 d, respectively. The δ18O and δ15N of NO2- was measured through time for both the abiotic and innoculated experiments. The ratio of ε18O/ε15N was 0.6 for the abiotic experiments and 3.1 when NO2- was reduced by S. loihica, thus indicating two different mechanisms for the NO2- reduction. Notably, there is a wide range of the ε18O/ε15N values in the literature for abiotic and biotic NO2- reduction, as such, the use of this ratio to distinguish between reduction mechanisms in natural systems should be taken with caution. Therefore, we suggest an additional constraint to identify the mechanisms (i.e. abiotic/biotic) controlling NO2- reduction in natural settings through the correlation of δ15N-NO2- and the aqueous Fe(II) concentration.


Assuntos
Compostos Férricos/química , Nitritos/química , Poluentes Químicos da Água/química , Catálise , Óxido Ferroso-Férrico , Nitratos , Óxido Nitroso , Oxirredução , Óxidos , Shewanella
16.
Int J Nanomedicine ; 15: 3333-3346, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32494133

RESUMO

Background and Objective: Cancer cells accumulate high concentrations of reactive oxygen species as a result of their faster and uninhibited metabolic activity. Cancer chemotherapeutic agents release an excess of severe adverse reactions as a result of targeting normal cells. This demands an improvement in targeted drug-delivery systems to selectively discharge anticancer drugs in the vicinity of such highly metabolically and mitotically active cells. Materials and Methods: Here, magnetic nanoparticles were synthesized by a traditional co-precipitation technique. Fe3O4@OA-CS-5-FLU-NPs were synthesized by an easy and rapid in situ loading method. The proposed Fe3O4@OA-CS-5-FLU-NPs were productively prepared as well as characterized by various spectroscopic and microscopic studies. Results: The targeted drug release profile of the Fe3O4@OA-CS-5-FLU-NPs was studied in the presence of ROS including H2O2 and pH induction. The released product, Fe3O4@OA-CS-5-FLU-NP, exhibited desirable levels of cytotoxicity and demonstrated morphological changes and inhibition of colony formation for A549 and HeLa S3 cancer cells. The IC50 values at 24 hours were 12.9 and 23 µg/mL, respectively. Conclusion: In summary, results from the MTT assay, fluorescence staining as well as colony formation assays, revealed that the Fe3O4@OA-CS-5-FLU-NPs were active and safe for anticancer biomedical applications. In summary, the present investigation provides a powerful nanostructured based system for improved cancer theranostics that should be further studied.


Assuntos
Quitosana/química , Sistemas de Liberação de Medicamentos , Compostos Férricos/química , Nanopartículas de Magnetita/química , Neoplasias/tratamento farmacológico , Espécies Reativas de Oxigênio/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Fluoruracila/farmacologia , Fluoruracila/uso terapêutico , Humanos , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Nanopartículas de Magnetita/ultraestrutura , Neoplasias/patologia , Ácido Oleico/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Difração de Raios X
17.
J Chromatogr A ; 1624: 461229, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540071

RESUMO

This work describes a sensitive and rapid analytical method for trace determination of polycyclic aromatic hydrocarbons (PAHs) in cosmetic samples. The proposed method is based on stir bar sorptive-dispersive microextraction (SBSDME). A magnetic composite made of CoFe2O4 magnetic nanoparticles embedded into reduced graphene oxide sheets is used as sorbent phase. After the extraction, the target analytes are desorbed in toluene and then analyzed by gas chromatography-mass spectrometry (GC-MS). The main parameters involved in the extraction procedure (i.e., composite amount, extraction time and desorption time) were evaluated and optimized to provide the best extraction efficiency. The method was successfully validated under the selected conditions, showing a linear range of at least up to 125 ng mL-1, instrumental and method limits of detection from 0.02 to 2.50 ng mL-1 and from 0.15 to 24.22 ng g-1, respectively, and relative standard deviations (RSD) below 10 % for all the target analytes. Standard addition combined with internal standard calibration was employed for quantification. The proposed method was successfully applied to the analysis of ten PAHs in four cosmetic products of different matrix. Several analytes between 14 and 464 ng g-1 were found, some of them prohibited in cosmetic products. This work expands the analytical potential of SBSDME technique to other analytes and to the use of new sorbent phases, showing the great versatility of this approach depending on the characteristics of the analytes.


Assuntos
Cosméticos/análise , Cromatografia Gasosa-Espectrometria de Massas , Grafite/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Microextração em Fase Sólida/métodos , Cobalto/química , Compostos Férricos/química , Limite de Detecção , Magnetismo , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação
18.
Ecotoxicol Environ Saf ; 201: 110830, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32559689

RESUMO

Iron (Fe) oxides are intimately coupled with phosphorus and closely associated with the bioavailability of potential toxic elements (PTEs) in soil. Thus, Fe oxides may influence the stabilization of PTEs in contaminated soils amended by phosphorus. To evaluate the effects of hematite (HMT) on the stabilization of PTEs, 1-5% (by weight) of HMT was added into a contaminated red soil amended with hydroxyapatite (HAP) to simulate naturally occurring Fe oxides. The stabilization efficiencies of soil copper (Cu) and cadmium (Cd) amended with HAP in soils with low, moderate, and high content of HMT were assessed after a 60-day incubation. HAP treated the soil with high rate HMT decreased the CaCl2-extractable and acid-soluble fractions of Cu and Cd than that of HAP alone. In particular, CaCl2-extactable Cu and Cd in the soil with 5% HMT amended by HAP were 91-95% and 41-68% lower than those amended with only HAP. High content of HMT in soil could decrease the concentration of labile phosphorus in the presence of HAP, but it did not increase the concentration of NaOH-extractable inorganic phosphorus (the fraction bound to Fe oxides). The concentrations of free and crystalline Fe oxides were significantly increased by adding high dosages of HMT with or without HAP. High content of HMT in soil amended by HAP reduced metal phytotoxicity and uptake by wheat shoots than the soil containing HAP without HMT. The results indicate that HMT can promote Cu and Cd stabilization while decrease labile phosphorus in red soil amended with HAP, suggesting that phosphorus-based amendments combined with Fe oxides can be used to stabilize PTEs in contaminated red soils.


Assuntos
Cádmio/análise , Cobre/análise , Durapatita/química , Compostos Férricos/química , Fósforo/análise , Poluentes do Solo/análise , Disponibilidade Biológica , Cádmio/metabolismo , China , Cobre/metabolismo , Fósforo/metabolismo , Solo/química , Poluentes do Solo/metabolismo , Triticum/efeitos dos fármacos , Triticum/metabolismo
19.
PLoS One ; 15(6): e0234136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32520947

RESUMO

Groundwater treatment sludge is a Fe/Mn-bearing waste that is mass produced in groundwater treatment plant. In this study, sludge was converted to a magnetic adsorbent (MA) by adding ascorbate. The sludge was weakly magnetised in the amorphous form with Fe and Mn contents of 28.8% and 8.1%, respectively. After hydrothermal treatment, Fe/Mn oxides in the sludge was recrystallised to siderite and rhodochrosite, with jacobsite as the intermediate in the presence of ascorbate. With an increment in ascorbate dosage, the obtained magnetic adsorbent had a significant increase in chromate adsorption but a decrease in magnetisation. When the Mascorbate/MFe molar ratio was 10, the produced MA-10 was a dumbbell-shaped nanorod with a length of 2-5 µm and a diameter of 0.5-1 µm. This MA-10 showed 183.2 mg/g of chromate adsorption capacity and 2.81 emu/g of magnetisation. The mechanism of chromate adsorption was surface coprecipitation of the generated Cr3+ and Fe3+/Mn4+ from redox reaction between chromate and siderite/rhodochrosite on MA-10, separately. This study demonstrated an efficient recycling route of waste sludge from groundwater treatment to produce MA for treating chromate-bearing wastewater.


Assuntos
Cromatos/química , Magnetismo , Nanotubos/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Carbonatos/química , Compostos Férricos/química , Ferro/química , Cinética , Manganês/química , Oxirredução , Óxidos/química
20.
Chemosphere ; 257: 127224, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32526469

RESUMO

In order to solve the problems of poor adsorption capacity and low stability in treating heavy metal wastewater with traditional constructed wetland (CW) fillers, a new type of filler, artificial zeolite spheres loaded with nano Fe-Al bimetallic oxide (hereinafter referred to as composite zeolite spheres), was prepared for Cr(VI) removal from wastewater. The results indicated that nano Fe-Al bimetallic oxide was an effective material for Cr(VI) removal with the maximal removal efficiency of 84.9% at initial Cr(VI) concentration of 20 mg/L (pH = 3). The micro-reactor experiment further verified that composite zeolite spheres had better removal performance on Cr(VI) than traditional filler. Fourier-transform infrared (FT-IR), X-ray diffractometry (XRD) and X-Ray photoemission spectroscopy (XPS) results demonstrated that -OH groups reduced Cr(VI) to Cr(III), and then the Cr(III) was removed by forming CrxFe1-x(OH)3 precipitation with Fe(III) or formed Cr(OH)3 precipitation with Al-OH through the ion exchange. This study provided an effective approach for treating Cr(VI) wastewater by using a new composite zeolite in constructed wetlands (CWs).


Assuntos
Cromo/análise , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Adsorção , Compostos Férricos/química , Metais Pesados , Óxidos , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias/química , Áreas Alagadas , Zeolitas/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA