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1.
Nat Commun ; 11(1): 5068, 2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-33033251

RESUMO

The mineralized collagen fibril is the basic building block of bone, and is commonly pictured as a parallel array of ultrathin carbonated hydroxyapatite (HAp) platelets distributed throughout the collagen. This orientation is often attributed to an epitaxial relationship between the HAp and collagen molecules inside 2D voids within the fibril. Although recent studies have questioned this model, the structural relationship between the collagen matrix and HAp, and the mechanisms by which collagen directs mineralization remain unclear. Here, we use XRD to reveal that the voids in the collagen are in fact cylindrical pores with diameters of ~2 nm, while electron microscopy shows that the HAp crystals in bone are only uniaxially oriented with respect to the collagen. From in vitro mineralization studies with HAp, CaCO3 and γ-FeOOH we conclude that confinement within these pores, together with the anisotropic growth of HAp, dictates the orientation of HAp crystals within the collagen fibril.


Assuntos
Colágeno/química , Minerais/química , Orientação Espacial , Osso e Ossos/química , Criança , Colágeno/ultraestrutura , Cristalização , Durapatita/química , Elétrons , Feminino , Humanos , Modelos Moleculares , Tomografia , Difração de Raios X
2.
Water Sci Technol ; 82(5): 967-983, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33031074

RESUMO

An easy-to-use, pollution-free and reusable beaded NiOx(OH)y catalyst for improving hypochlorite oxidation was prepared by impregnating the mixture of persulfate and alkali over alumina and then reduced it with Ni2+. The effects of catalyst preparation conditions and reaction parameters on NaClO conversion rate and Ni2+ dissolution rate were studied. Impregnating the γ-Al2O3 beads in PS/OH- mixed solution with 0.59 M PS and PS/OH- molar ratio of 1.1, and then reducing with 0.8 M Ni2+ solution is the best condition for preparing catalyst. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The best catalytic layer is characterized by high content of chemisorbed oxygen which can be converted into atomic oxygen. The hypochlorite conversion rate increased with the catalyst dosage and reuse times, and decreased with available chlorine, while pH of hypochlorite solution had little effect on the conversion rate. After running stably for 120 h in continuous flow test, the chemisorbed oxygen content in the optimal catalytic layer decreased slightly. Atomic oxygen plays an important role in the decolorization of dye solution by NaClO/NiOx(OH)y system. The oxidant consumption cost of this process is much cheaper than Fenton reagent. The prepared catalyst has great potential in hypochlorite decomposition and wastewater treatment.


Assuntos
Ácido Hipocloroso , Águas Residuárias , Catálise , Oxirredução , Difração de Raios X
3.
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
4.
Waste Manag ; 118: 350-359, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32927388

RESUMO

It's an oversimplification to evaluate the reactivity of fly ash in geopolymerization using bulk elemental ratios like Si/Al. In this study, quantitative XRD by means of Rietveld refinement was employed to proportionate the mineral and glass phases of five fly ashes. The chemical environment of Si and Al in the fly ashes was investigated by 29Si and 27Al MAS NMR spectra. By counting the contributions of Al phase from mullite, the proportion of different coordination states of Al in the glass phase was speculated. The results reveal that the coordination number of Al is directly associated with the amount of alkali cations present in the glass phase for the most fly ashes, whereby higher the alkali content, the more four fold coordinated Al species are present in the system. Five and six fold coordinated Al as well as highly polymerized silicate species are also present in the glass structure of the fly ash. All these results point to an inherent inhomogeneous glass structure in fly ash. Despite that, a reactivity index derived from the NBO/T ratio (Non-Bridging Oxygen per Tetrahedral network former, e.g. SiO44-, AlO45-) modelled in a simplified glass setup, correlates well with the reaction heat of the geopolymers.


Assuntos
Cinza de Carvão , Polímeros , Álcalis , Espectroscopia de Ressonância Magnética , Difração de Raios X
5.
Nat Commun ; 11(1): 4722, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32948764

RESUMO

Precisely controlled deuterium labeling at specific sites of N-alkyl drugs is crucial in drug-development as over 50% of the top-selling drugs contain N-alkyl groups, in which it is very challenging to selectively replace protons with deuterium atoms. With the goal of achieving controllable isotope-labeling in N-alkylated amines, we herein rationally design photocatalytic water-splitting to furnish [H] or [D] and isotope alkanol-oxidation by photoexcited electron-hole pairs on a polymeric semiconductor. The controlled installation of N-CH3, -CDH2, -CD2H, -CD3, and -13CH3 groups into pharmaceutical amines thus has been demonstrated by tuning isotopic water and methanol. More than 50 examples with a wide range of functionalities are presented, demonstrating the universal applicability and mildness of this strategy. Gram-scale production has been realized, paving the way for the practical photosynthesis of pharmaceuticals.


Assuntos
Aminas/química , Aminas/metabolismo , Luz , Semicondutores , Alquilação , Aminas/farmacologia , Catálise , Deutério , Oxirredução , Preparações Farmacêuticas , Prótons , Água , Difração de Raios X
6.
J Chromatogr A ; 1626: 461354, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797834

RESUMO

The Al-doped mesoporous crystalline material-41 (Al-MCM-41) composite was prepared and applied as fiber coating material of headspace solid-phase microextraction (HS-SPME) for extraction of polycyclic aromatic hydrocarbons (PAHs) from human urine. Five PAHs including acenaphthene, fluorene, phenanthrene, anthracene, and pyrene are chosen as target analytes to evaluate the performance of the material by GC-FID analysis. The mesoporous Al-MCM-41 composite was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, nitrogen adsorption/desorption measurement, and thermogravimetric analysis. The parameters affecting the extraction efficiency of HS-SPME were investigated. Under the optimal conditions, the method exhibits ideal linearity for target analytes in the range of 0.3-600 ng⋅mL-1 with the coefficients (R2) equal or higher than 0.9906. The enrichment factors are calculated from 540 to 1760. The limits of detection (LODs) and limits of quantitation (LOQs) are between the ranges of 0.06-0.18 and 0.3-0.9 ng⋅mL-1, respectively. The relative standard deviations (RSDs) (n = 5) of intra-day and inter-day are in the ranges of 1.08-7.49% and 2.84-18.3% respectively. The fiber-to-fiber reproducibility (n = 3) is in the range of 6.47-13.9%. The method was successfully applied for the analysis of PAHs in human urine with reasonable recoveries which is ranging from 73.29 to 116.1%.


Assuntos
Alumínio/química , Hidrocarbonetos Policíclicos Aromáticos/urina , Dióxido de Silício/química , Microextração em Fase Sólida/métodos , Adsorção , Cristalização , Humanos , Limite de Detecção , Masculino , Concentração Osmolar , Porosidade , Padrões de Referência , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Fatores de Tempo , Difração de Raios X
7.
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
8.
Ecotoxicol Environ Saf ; 202: 110924, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800211

RESUMO

Fabrication of poly-(N-isopropylmethacrylamide-co-methacrylic acid) [p(NMA)] microgels to be utilized as microreactors to synthesize stable Ag nanoparticles for catalytic reductive degradation of dyes has been addressed in this work. Both p(NMA) microgel and Ag-p(NMA) hybrid microgel systems have been analyzed by Fourier transform infra-red and Dynamic light scattering, Ultraviolet-Visible spectroscopy, X-ray diffraction and Transmission electron microscopy. Catalytic activity of Ag-p(NMA) towards reductive degradation of Congo Red (CR), Methyl Orange (MO) and Alizarin Yellow (AY) was investigated under different operating conditions. Spectrophotometry was employed to check the progress of reaction while the rate constant (kapp) value of degradation reaction was determined under various conditions to optimize reaction parameters for rapid and economical degradation of these dyes. An increase in kapp value was observed by increasing feed content of dye up to a certain value that decreases again by further increment in dye concentration which reflects that catalysis follows Langmuir-Hinshelwood mechanism. A gradual increase in the kapp value was also observed with increasing quantity of hybrid microgel used as a catalyst. By comparing kapp values of degradation of aforementioned dyes, it was found that Ag-p(NMA) hybrid microgel gives better activity for MO dye degradation in comparison to catalytic degradation of CR and AY.


Assuntos
Compostos Azo/química , Nanopartículas Metálicas/química , Prata/química , Catálise , Corantes/química , Vermelho Congo/química , Hidrogéis/química , Microscopia Eletrônica de Transmissão , Polímeros/química , Espectrofotometria , Difração de Raios X
9.
PLoS One ; 15(8): e0237726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813737

RESUMO

In this in vitro study, spherical mesoporous bioactive glass nanoparticle (MBGN) and non-porous bioactive glass nanoparticle (BGN) were fabricated. The impact of mesopores on dentinal tubule occlusion and bioactivity was compared to examine the potential of these materials in alleviating dentine hypersensitivity (DH). MBGN, dense BGN were synthesized by sol-gel methods and characterized. Bioactivity and ion dissolution ability were analyzed. Twenty-four simulated sensitive dentin discs were prepared and randomly divided into three groups (n = 8 each); Group 1, no treatment; Group 2, Dense BGN; Group 3, MBGN. Then, four discs per group were treated with 6wt.% citric acid challenge to determine the acidic resistance. The effects on dentinal tubule occlusion were observed by FESEM. The microtensile bond strength (MTBS) was also measured. Cytotoxicity was examined using the MTT assay. According to the results, dense BGN without mesopore and MBGN with mesopore were successfully fabricated. Dense BGN and MBGN occluded the dentinal tubule before and after acid challenge. However, only MBGN formed a membrane-like layer and showed hydroxyapatite formation after soaking SBF solution. There were no significant differences in MTBS among dense BGN, MBGN (P>0.05). The cell viability was above 72% of both materials. The higher bioactivity of MBGN compared with that of dense BGN arises from the structural difference and it is anticipated to facilitate dentin remineralization by inducing hydroxyapatite deposition within the dentinal tubule.


Assuntos
Dessensibilizantes Dentinários/administração & dosagem , Sensibilidade da Dentina/terapia , Dentina/efeitos dos fármacos , Vidro/química , Nanopartículas/administração & dosagem , Dente Pré-Molar , Dentina/metabolismo , Dessensibilizantes Dentinários/química , Dessensibilizantes Dentinários/farmacocinética , Permeabilidade da Dentina/efeitos dos fármacos , Sensibilidade da Dentina/patologia , Liberação Controlada de Fármacos , Durapatita/metabolismo , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanopartículas/química , Nanopartículas/ultraestrutura , Porosidade , Propriedades de Superfície , Resistência à Tração , Remineralização Dentária/métodos , Difração de Raios X
10.
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
11.
PLoS One ; 15(8): e0237909, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32853249

RESUMO

The influence of water content on mode I fracture toughness (KIc) of mudstones has been studied using semi-circular bend (SCB) specimens subject to three-point bendings. And the mudstone SCB specimens are divided into three types, including Type-A, Type-B and Type-C, corresponding to the three configurations of the bedding planes, including divider direction, arrester direction, and transverse direction, respectively. The test results show that the values of KIc for the three types of specimens are different due to the bedding structure, the Type-A specimens have the largest value of KIc for the same soak period, while the Type-C specimens possess the smallest value. As the soak period increases, the KIc of the three kinds of mudstone specimens decreases, and the fracture mechanisms of the specimens change gradually from the brittle failure form to the ductile failure form. Moreover, the standard deviation was used to quantify the anisotropy degree of the KIc of the mudstone samples. As the water content increases, the standard deviation increases from 0.057 to 0.139, which indicates a significant increase in anisotropy of the KIc of the mudstone specimens. In addition, the acoustic emission (AE) system was used to detect the AE events associated with the fracture initiation and propagation in the mudstone specimens for the different water content, with the raising water content, the cumulative AE events decrease, and the standard deviation of AE events increases, repesenting that the anisotropy of the AE events of the three types of specimens becomes more prominent. Further, the relationship between the tensile strength (σt) and the KIc of the three types of mudstone specimens for different water contents has been proved to be the linear relation.


Assuntos
Sedimentos Geológicos/química , Água/química , Acústica , Anisotropia , Difração de Raios X
12.
Nat Commun ; 11(1): 3894, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753597

RESUMO

Here, we demonstrate the self-assembly of the antimicrobial human LL-37 active core (residues 17-29) into a protein fibril of densely packed helices. The surface of the fibril encompasses alternating hydrophobic and positively charged zigzagged belts, which likely underlie interactions with and subsequent disruption of negatively charged lipid bilayers, such as bacterial membranes. LL-3717-29 correspondingly forms wide, ribbon-like, thermostable fibrils in solution, which co-localize with bacterial cells. Structure-guided mutagenesis analyses supports the role of self-assembly in antibacterial activity. LL-3717-29 resembles, in sequence and in the ability to form amphipathic helical fibrils, the bacterial cytotoxic PSMα3 peptide that assembles into cross-α amyloid fibrils. This argues helical, self-assembling, basic building blocks across kingdoms of life and points to potential structural mimicry mechanisms. The findings expose a protein fibril which performs a biological activity, and offer a scaffold for functional and durable biomaterials for a wide range of medical and technological applications.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Amiloide/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Bactérias/metabolismo , Benzotiazóis , Catelicidinas/farmacologia , Cristalografia por Raios X , Gorilla gorilla , Humanos , Testes de Sensibilidade Microbiana , Micrococcus luteus/efeitos dos fármacos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Modelos Moleculares , Conformação Proteica , Staphylococcus hominis/efeitos dos fármacos , Difração de Raios X
13.
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
14.
Int J Nanomedicine ; 15: 5389-5403, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801695

RESUMO

Hypothesis: Developing oral formulations to enable effective release of poorly water-soluble drugs like progesterone is a major challenge in pharmaceutics. Coaxial electrospray can generate drug-loaded nanoparticles of strategic compositions and configurations to enhance physiological dissolution and bioavailability of poorly water-soluble drug progesterone. Experiments: Six formulations comprising nanoparticles encapsulating progesterone in different poly(lactide-co-glycolide) (PLGA) matrix configurations and compositions were fabricated and characterized in terms of morphology, molecular crystallinity, drug encapsulation efficiency and release behavior. Findings: A protocol of fabrication conditions to achieve 100% drug encapsulation efficiency in nanoparticles was developed. Scanning electron microscopy shows smooth and spherical morphology of 472.1±54.8 to 588.0±92.1 nm in diameter. Multiphoton Airyscan super-resolution confocal microscopy revealed core-shell nanoparticle configuration. Fourier transform infrared spectroscopy confirmed presence of PLGA and progesterone in all formulations. Diffractometry indicated amorphous state of the encapsulated drug. UV-vis spectroscopy showed drug release increased with hydrophilic copolymer glycolide ratio while core-shell formulations with progesterone co-dissolved in PLGA core exhibited enhanced release over five hours at 79.9±1.4% and 70.7±3.5% for LA:GA 50:50 and 75:25 in comparison with pure progesterone without polymer matrix in the core at 67.0±1.7% and 57.5±2.8%, respectively. Computational modeling showed good agreement with the experimental drug release behavior in vitro.


Assuntos
Nanopartículas/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Progesterona/administração & dosagem , Progesterona/farmacocinética , Disponibilidade Biológica , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Microscopia Eletrônica de Varredura , Nanopartículas/administração & dosagem , Tamanho da Partícula , Solubilidade , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Difração de Raios X
15.
Int J Nanomedicine ; 15: 5417-5432, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801697

RESUMO

Introduction: Green-based materials have been increasingly studied to circumvent off-target cytotoxicity and other side-effects from conventional chemotherapy. Materials and Methods: Here, cellulose fibers (CF) were isolated from rice straw (RS) waste by using an eco-friendly alkali treatment. The CF network served as an anticancer drug carrier for 5-fluorouracil (5-FU). The physicochemical and thermal properties of CF, pure 5-FU drug, and the 5-FU-loaded CF (CF/5-FU) samples were evaluated. The samples were assessed for in vitro cytotoxicity assays using human colorectal cancer (HCT116) and normal (CCD112) cell lines, along with human nasopharyngeal cancer (HONE-1) and normal (NP 460) cell lines after 72-hours of treatment. Results: XRD and FTIR revealed the successful alkali treatment of RS to isolate CF with high purity and crystallinity. Compared to RS, the alkali-treated CF showed an almost fourfold increase in surface area and zeta potential of up to -33.61 mV. SEM images illustrated the CF network with a rod-shaped structure and comprised of ordered aggregated cellulose. TGA results proved that the thermal stability of 5-FU increased within the drug carrier. Based on UV-spectroscopy measurements for 5-FU loading into CF, drug loading encapsulation efficiency was estimated to be 83 ±0.8%. The release media at pH 7.4 and pH 1.2 showed a maximum drug release of 79% and 46%, respectively, over 24 hours. In cytotoxicity assays, CF showed almost no damage, while pure 5-FU killed most of the both normal and cancer cells. Impressively, the drug-loaded sample of CF/5-FU at a 250 µg/mL concentration demonstrated a 58% inhibition against colorectal cancer cells, but only a 23% inhibition against normal colorectal cells. Further, a 62.50 µg/mL concentration of CF/5FU eliminated 71% and 39% of nasopharyngeal carcinoma and normal nasopharyngeal cells, respectively. Discussion: This study, therefore, showed the strong potential anticancer activity of the novel CF/5-FU formulations, warranting their further investigation.


Assuntos
Celulose/química , Portadores de Fármacos/química , Fluoruracila/administração & dosagem , Fluoruracila/farmacologia , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/farmacologia , Linhagem Celular , Linhagem Celular Tumoral , Neoplasias Colorretais/tratamento farmacológico , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/farmacocinética , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Fluoruracila/farmacocinética , Células HCT116 , Humanos , Neoplasias Nasofaríngeas/tratamento farmacológico , Oryza/química , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios X
16.
Int J Nanomedicine ; 15: 5517-5526, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801703

RESUMO

Introduction: Hypertension is a major health problem worldwide and is typically treated using oral drugs. However, the frequency of oral administration may result in poor patient compliance, and reduced bioavailability owing to the first-pass effect can also prove problematic. Methods: In this study, we developed a new transdermal-drug-delivery system (TDDS) for the treatment of hypertension using atenolol (ATE) based on poly(acrylic acid) (PAA)-decorated three-dimensional (3D) flower-like MoS2 nanoparticles (PAA-MoS2 NPs) that respond to NIR laser irradiation. The PAA-modified MoS2 NPs were synthesized and characterized using attenuated total reflection Fourier-transform infrared spectroscopy, X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and the sedimentation equilibrium method. The drug-loading efficiency and photothermal conversion effect were also explored. Results: The results showed that the colloidally stable PAA-MoS2 NPs exhibited a high drug-loading capacity of 54.99% and high photothermal conversion ability. Further, the capacity of the PAA-MoS2 NPs for controlled release was explored using in vitro drug-release and skin-penetration studies. The drug-release percentage was 44.72 ± 1.04%, and skin penetration was enhanced by a factor of 1.85 in the laser-stimulated group. Sustained and controlled release by the developed TDDS were observed with laser stimulation. Moreover, in vivo erythema index analysis verified that the PAA-MoS2 NPs did not cause skin irritation. Discussion: Our findings demonstrate that PAA-MoS2 NPs can be used as a new carrier for transdermal drug delivery for the first time.


Assuntos
Anti-Hipertensivos/administração & dosagem , Atenolol/administração & dosagem , Dissulfetos/química , Sistemas de Liberação de Medicamentos/métodos , Molibdênio/química , Nanopartículas/administração & dosagem , Resinas Acrílicas/química , Administração Cutânea , Animais , Anti-Hipertensivos/farmacocinética , Atenolol/efeitos adversos , Atenolol/farmacocinética , Sistemas de Liberação de Medicamentos/efeitos adversos , Liberação Controlada de Fármacos , Difusão Dinâmica da Luz , Eritema/induzido quimicamente , Humanos , Lasers , Masculino , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Coelhos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
17.
J Environ Manage ; 274: 111155, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32805472

RESUMO

This work reports on the potential application of UiO-66 in gas sweetening and its structural stability against water, air, dimethylformamide (DMF), and chloroform. The UiO-66 nanoparticles were solvothermally synthesized at different scales and activated via solvent exchange technique using chloroform, methanol, and ethanol. Thus prepared and aged MOFs were characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), and nitrogen adsorption-desorption analysis. The chloroform-activated MOF showed the largest surface area among all activation solvents, and presented high uptakes of 8.8 and 4.3 mmol/g for CO2 and CH4, respectively, at 298 K and 30 bar. This might be due to removing all unreacted organic ligands and DMF molecules from the pores of the framework. The UiO-66 nanoparticles are stable at the experimental conditions with no significant loss in crystalline structure and gas adsorption ability even after aging under different conditions for one year. The UiO-66 could be easily regenerated at 373 K with no observed significant reduction in gas uptakes even after five consecutive adsorption-desorption cycles. The present findings suggest the excellent potential of the UiO-66-derived MOFs as the promising materials for CO2/CH4 separation at low pressures and results can be applied in practical natural gas sweetening.


Assuntos
Poluentes Químicos da Água/análise , Água , Adsorção , Solventes , Difração de Raios X
18.
PLoS One ; 15(8): e0237583, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32804936

RESUMO

Identification and quantification of plant flavonoids are critical to pharmacokinetic study and pharmaceutical quality control due to their distinct pharmacological functions. Here we report on a novel plant flavonoid electrochemical sensor for sensitive and selective detection of dihydromyricetin (DMY) based on double- layered membranes consisting of gold nanoparticles (Au) anchored on reduced graphene oxide (rGO) and molecularly imprinted polymers (MIPs) modified glassy carbon electrode (GCE). Both rGO-Au and MIPs membranes were directly formed on GCE via in-situ electrochemical reduction and polymerization processes step by step. The compositions, morphologies, and electrochemical properties of membranes were investigated with X-ray powder diffractometry (XRD), Fourier transform infrared spectrum (FTIR), Field emission scanning electron microscopy (FESEM) combined with various electrochemical methods. The fabricated electrochemical sensor labeled as GCE│rGO-Au/MIPs exhibited excellent performance in determining of DMY under optimal experimental conditions. A wide linear detection range (LDR) ranges from 2.0×10-8 to 1.0×10-4 M together with a low limit of detection (LOD) of 1.2×10-8 M (S/N = 3) were achieved. Moreover, the electrochemical sensor was employed to determine DMY in real samples with satisfactory results.


Assuntos
Carbono/química , Técnicas Eletroquímicas/instrumentação , Flavonoides/análise , Flavonóis/análise , Grafite/química , Técnicas Biossensoriais/métodos , Eletrodos , Ouro , Limite de Detecção , Nanopartículas Metálicas , Impressão Molecular , Extratos Vegetais/análise , Polímeros/síntese química , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
19.
AAPS PharmSciTech ; 21(5): 181, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32607628

RESUMO

Cocrystals have gained a lot of consideration regarding its superior role in enhancement of solubility and dissolution of the included API. Cocrystals could be converted to coamorphous systems via different techniques like milling and quench cooling; however, the use of spray-drying technique has not been investigated before. So, the aim of this study was to explore the effect of spray drying on the amorphization of indomethacin/nicotinamide, INDNIC, as model cocrystals. Spray-drying operating parameters were optimized using the Taguchi design of experiment for maximum powder yield and low moisture content. The obtained INDNIC spray-dried cocrystals were characterized for their degree of crystallinity, morphology, moisture content, and dissolution performance. In addition, stability study was performed at different temperature and humidity conditions. Experimental design results delineate that spray-drying inlet temperature and cocrystal concentrations as the most influential factors for maximum powder yield and low moisture content. Powder X-ray diffraction and differential scanning calorimetry studies revealed the conversion of INDNIC cocrystals to a partial coamorphous or coamorphous structure without dissociation of INDNIC molecular structure. INDNIC coamorphous powders showed a significantly higher release of IND compared with cocrystals and remain physically stable for 2 months when stored in the refrigerator.


Assuntos
Dessecação/métodos , Estabilidade de Medicamentos , Indometacina/química , Niacinamida/química , Varredura Diferencial de Calorimetria , Composição de Medicamentos/métodos , Estrutura Molecular , Pós/química , Solubilidade , Difração de Raios X
20.
Nat Commun ; 11(1): 3712, 2020 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-32709842

RESUMO

Metal hydrides have been rarely used in biomedicine. Herein, we fabricate titanium hydride (TiH1.924) nanodots from its powder form via the liquid-phase exfoliation, and apply these metal hydride nanodots for effective cancer treatment. The liquid-phase exfoliation is an effective method to synthesize these metal hydride nanomaterials, and its efficiency is determined by the matching of surface energy between the solvent and the metal hydrides. The obtained TiH1.924 nanodots can produce reactive oxygen species (ROS) under ultrasound, presenting a highly efficient sono-sensitizing effect. Meanwhile, TiH1.924 nanodots with strong near-infrared (NIR) absorbance can serve as a robust photothermal agent. By using the mild photothermal effect to enhance intra-tumoral blood flow and improve tumor oxygenation, a remarkable synergistic therapeutic effect is achieved in the combined photothermal-sonodynamic therapy. Importantly, most of these TiH1.924 nanodots can be cleared out from the body. This work presents the promises of functional metal hydride nanomaterials for biomedical applications.


Assuntos
Antineoplásicos/química , Nanopartículas/uso terapêutico , Nanoestruturas/química , Titânio/química , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Nanopartículas/química , Nanotecnologia , Espécies Reativas de Oxigênio , Difração de Raios X
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