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1.
Molecules ; 26(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34361717

RESUMO

The development of bio-based nanocomposites is of high scientific and industrial interest, since they offer excellent advantages in creating functional materials. However, dispersion and distribution of the nanomaterials inside the polymer matrix is a key challenge to achieve high-performance functional nanocomposites. In this context, for better dispersion, biobased triethyl citrate (TEC) as a dispersing agent in a liquid-assisted extrusion process was used to prepare the nanocomposites of poly (lactic acid) (PLA) and chitin nanocrystals (ChNCs). The aim was to identify the effect of the TEC content on the dispersion of ChNCs in the PLA matrix and the manufacturing of a functional nanocomposite. The nanocomposite film's optical properties; microstructure; migration of the additive and nanocomposites' thermal, mechanical and rheological properties, all influenced by the ChNC dispersion, were studied. The microscopy study confirmed that the dispersion of the ChNCs was improved with the increasing TEC content, and the best dispersion was found in the nanocomposite prepared with 15 wt% TEC. Additionally, the nanocomposite with the highest TEC content (15 wt%) resembled the mechanical properties of commonly used polymers like polyethylene and polypropylene. The addition of ChNCs in PLA-TEC15 enhanced the melt viscosity, as well as melt strength, of the polymer and demonstrated antibacterial activity.


Assuntos
Antibacterianos/síntese química , Quitina/química , Citratos/química , Nanocompostos/química , Nanopartículas/química , Poliésteres/química , Antibacterianos/farmacologia , Módulo de Elasticidade , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Reologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resistência à Tração , Viscosidade
2.
Molecules ; 26(16)2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34443453

RESUMO

Understanding the formation process and the spatial distribution of nanoparticle (NP) clusters on amyloid fibrils is an essential step for the development of NP-based methods to inhibit aggregation of amyloidal proteins or reverse the assembling trend of the proto-fibrillary complexes that prompts pathogenesis of neuro degeneration. For this, a detailed structural determination of the diverse hybrid assemblies that are forming is needed, which can be achieved by advanced X-ray scattering techniques. Using a combined solution small angle X-ray scattering (SAXS) and atomic force microscopy (AFM) approach, this study investigates the intrinsic trends of the interaction between lysozyme amyloid fibrils (LAFs) and Fe3O4 NPs before and after fibrillization at nanometer resolution. AFM images reveal that the number of NP clusters interacting with the lysozyme fibers does not increase significantly with NP volume concentration, suggesting a saturation in NP aggregation on the fibrillary surface. The data indicate that the number of non-adsorbed Fe3O4 NPs is highly dependent on the timing of NP infusion within the synthesis process. SAXS data yield access to the spatial distribution, aggregation manner and density of NP clusters on the fibrillary surfaces. Employing modern data analysis approaches, the shape and internal structural morphology of the so formed nanocomposites are revealed. The combined experimental approach suggests that while Fe3O4 NPs infusion does not prevent the fibril-formation, the variation of NP concentration and size at different stages of the fibrillization process can impose a pronounced impact on the superficial and internal structural morphologies of these nanocomposites. These findings may be applicable in devising advanced therapeutic treatments for neurodegenerative diseases and designing novel bio-inorganic magnetic devices. Our results further demonstrate that modern X-ray methods give access to the structure of-and insight into the formation process of-biological-inorganic hybrid structures in solution.


Assuntos
Amiloide/química , Microscopia de Força Atômica , Muramidase/metabolismo , Nanocompostos/química , Nanopartículas/química , Espalhamento a Baixo Ângulo , Difração de Raios X , Animais , Galinhas , Modelos Moleculares , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura
3.
Int J Mol Sci ; 22(14)2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34299003

RESUMO

Here, we designed paper sheets coated with chitosan, bacterial cellulose (nanofibers), and ZnO with boosted antibacterial and mechanical activity. We investigated the compositions, with ZnO exhibiting two different sizes/shapes: (1) rods and (2) irregular sphere-like particles. The proposed processing of bacterial cellulose resulted in the formation of nanofibers. Antimicrobial behavior was tested using E. coli ATCC® 25922™ following the ASTM E2149-13a standard. The mechanical properties of the paper sheets were measured by comparing tearing resistance, tensile strength, and bursting strength according to the ISO 5270 standard. The results showed an increased antibacterial response (assigned to the combination of chitosan and ZnO, independent of its shape and size) and boosted mechanical properties. Therefore, the proposed composition is an interesting multifunctional mixture for coatings in food packaging applications.


Assuntos
Biopolímeros/química , Biopolímeros/farmacologia , Celulose/química , Quitosana/química , Nanocompostos/química , Embalagem de Produtos/métodos , Óxido de Zinco/química , Anti-Infecciosos , Celulose/ultraestrutura , Escherichia coli , Testes Mecânicos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanocompostos/ultraestrutura , Nanofibras/química , Nanofibras/ultraestrutura , Propriedades de Superfície , Resistência à Tração , Difração de Raios X
4.
Int J Nanomedicine ; 16: 4197-4208, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34188469

RESUMO

Introduction: Intracellular protein delivery is emerging as a potential strategy to revolutionize therapeutics in the field of biomedicine, aiming at treating a wide range of diseases including cancer, inflammatory diseases and other oxidative stress-related disorders with high specificity. However, the current challenges and limitations are addressed to either synthetically or biologically through multipotency of engineering, such as protein modification, insufficient delivery of large-size proteins, deficiency or mutation of proteins, and high cytotoxicity. Methods: We prepared the nanocomposites by mixing protein with PEI1200 at a certain molar ratio and demonstrated that it can deliver proteins into living cells in high efficiency and safety through the following experiments, such as dynamic light scattering, fluorescent detection, agarose gel electrophoresis, ß-Galactosidase activity detection, immunofluorescence staining, digital fluorescent detection, cell viability assay and flow cytometry. Results: The self-assembly of PEI1200/protein nanocomposites with appropriate molar ratio (4:1 and 8:1) could provide efficiently delivery of active proteins to a variety of cell types in the presence of serum. The nanocomposites could continuously release protein up to 96 h in their desired intracellular locations. In addition, these nanocomposites were able to preserve protein activity while maintain low cytotoxicity (when final concentration <1 µg/mL). Conclusion: Collectively, PEI1200-based delivery system provided an alternative strategy to direct protein delivery in high efficiency and safety, offering increased potential applications in clinical biomedicine.


Assuntos
Espaço Intracelular/metabolismo , Polietilenoimina/química , Proteínas/administração & dosagem , Morte Celular , Linhagem Celular Tumoral , Sobrevivência Celular , Proteínas de Fluorescência Verde/metabolismo , Humanos , Células-Tronco Mesenquimais/metabolismo , Peso Molecular , Nanocompostos/química , Nanocompostos/ultraestrutura
5.
Int J Mol Sci ; 22(11)2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34071337

RESUMO

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8-10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.


Assuntos
Antibacterianos/química , Arecaceae/química , Celulose/química , Nanocompostos/química , Nanofibras/química , Óxido de Zinco/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Estabilidade de Medicamentos , Concentração de Íons de Hidrogênio , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Microscopia Eletrônica , Nanocompostos/ultraestrutura , Nanofibras/ultraestrutura , Tamanho da Partícula , Borracha/química , Salmonella/efeitos dos fármacos , Salmonella/crescimento & desenvolvimento , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Difração de Raios X
6.
Molecules ; 26(7)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33916094

RESUMO

The degradation and mechanical properties of potential polymeric materials used for green manufacturing are significant determinants. In this study, cellulose nanofibre was prepared from Schizostachyum brachycladum bamboo and used as reinforcement in the PLA/chitosan matrix using melt extrusion and compression moulding method. The cellulose nanofibre(CNF) was isolated using supercritical carbon dioxide and high-pressure homogenisation. The isolated CNF was characterised with transmission electron microscopy (TEM), FT-IR, zeta potential and particle size analysis. The mechanical, physical, and degradation properties of the resulting biocomposite were studied with moisture content, density, thickness swelling, tensile, flexural, scanning electron microscopy, thermogravimetry, and biodegradability analysis. The TEM, FT-IR, and particle size results showed successful isolation of cellulose nanofibre using this method. The result showed that the physical, mechanical, and degradation properties of PLA/chitosan/CNF biocomposite were significantly enhanced with cellulose nanofibre. The density, thickness swelling, and moisture content increased with the addition of CNF. Also, tensile strength and modulus; flexural strength and modulus increased; while the elongation reduced. The carbon residue from the thermal degradation and the glass transition temperature of the PLA/chitosan/CNF biocomposite was observed to increase with the addition of CNF. The result showed that the biocomposite has potential for green and sustainable industrial application.


Assuntos
Materiais Biocompatíveis/química , Celulose/química , Quitosana/química , Nanocompostos/química , Nanofibras/química , Poliésteres/química , Sasa/química , Algoritmos , Fenômenos Químicos , Modelos Teóricos , Nanocompostos/ultraestrutura , Nanofibras/ultraestrutura , Tamanho da Partícula , Termogravimetria
7.
Int J Nanomedicine ; 16: 2715-2733, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33859474

RESUMO

Background: Due to educational, social and economic reasons, more and more women are delaying childbirth. However, advanced maternal age is associated with several adverse pregnancy outcomes, and in particular a high risk of Down's syndrome (DS). Hence, it is increasingly important to be able to detect fetal Down's syndrome (FDS). Methods: We developed an effective, highly sensitive, surface plasmon resonance (SPR) biosensor with biochemically amplified responses using carboxyl-molybdenum disulfide (MoS2) film. The use of carboxylic acid as a surface modifier of MoS2 promoted dispersion and formed specific three-dimensional coordination sites. The carboxylic acid immobilized unmodified antibodies in a way that enhanced the bioaffinity of MoS2 and preserved biorecognition properties of the SPR sensor surface. Complete antigen pregnancy-associated plasma protein-A2 (PAPP-A2) conjugated with the carboxyl-MoS2-modified gold chip to amplify the signal and improve detection sensitivity. This heterostructure interface had a high work function, and thus improved the efficiency of the electric field energy of the surface plasmon. These results provide evidence that the interface electric field improved performance of the SPR biosensor. Results: The carboxyl-MoS2-based SPR biosensor was used successfully to evaluate PAPP-A2 level for fetal Down's syndrome screening in maternal serum samples. The detection limit was 0.05 pg/mL, and the linear working range was 0.1 to 1100 pg/mL. The women with an SPR angle >46.57 m° were more closely associated with fetal Down's syndrome. Once optimized for serum Down's syndrome screening, an average recovery of 95.2% and relative standard deviation of 8.5% were obtained. Our findings suggest that carboxyl-MoS2-based SPR technology may have advantages over conventional ELISA in certain situations. Conclusion: Carboxyl-MoS2-based SPR biosensors can be used as a new diagnostic technology to respond to the increasing need for fetal Down's syndrome screening in maternal serum samples. Our results demonstrated that the carboxyl-MoS2-based SPR biosensor was capable of determining PAPP-A2 levels with acceptable accuracy and recovery. We hope that this technology will be investigated in diverse clinical trials and in real case applications for screening and early diagnosis in the future.


Assuntos
Técnicas Biossensoriais , Dissulfetos/química , Síndrome de Down/sangue , Síndrome de Down/diagnóstico , Imunoensaio/métodos , Molibdênio/química , Proteína Plasmática A Associada à Gravidez/análise , Diagnóstico Pré-Natal , Adulto , Anticorpos/metabolismo , Calibragem , Feminino , Ouro , Humanos , Proteínas Imobilizadas/metabolismo , Nanocompostos/ultraestrutura , Espectroscopia Fotoeletrônica , Gravidez , Ressonância de Plasmônio de Superfície
8.
Int J Biol Macromol ; 181: 868-876, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33838201

RESUMO

In this study, starch-based nanocomposite films reinforced by cross-linked starch nanocrystals (CSNCs) were successfully prepared. CSNCs were obtained by cross-linking reaction between starch nanocrystals (SNCs) and sodium hexametaphosphate (SHMP). Through the characterization and comparison of SNCs and CSNCs in microscopic morphology, degree of substitution, swelling degree, XRD spectrum, and FTIR spectrum, the successful progress of the cross-linking reaction was confirmed. Besides, the effects of adding CSNCs on physiochemical properties of the nanocomposite films including mechanical properties, water vapor permeability, and contact angle were studied. The results confirmed that CSNCs had good enhancement effects on the physicochemical properties of starch-based films due to the self-reinforcing effect, and when the CSNCs content reached 10%, the nanocomposite film had the best overall performance. We further evaluated the cytotoxicity of the nanocomposite. Taken together, it is believed that the reported self-reinforced starch-based films are very promising for food packaging and preservation.


Assuntos
Reagentes para Ligações Cruzadas/química , Nanocompostos/química , Nanopartículas/química , Amido/química , Animais , Morte Celular , Linhagem Celular , Cor , Camundongos , Nanocompostos/ultraestrutura , Tamanho da Partícula , Permeabilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/ultraestrutura , Vapor , Difração de Raios X
9.
Int J Biol Macromol ; 180: 439-457, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33705835

RESUMO

In this approach, we assembled AgNps on cotton by using iota-carrageenan as a carbohydrate polymer under ultrasonic waves. UV-Vis spectroscopy revealed that iota-carrageenan free radicals increased the absorbance values of AgNps at 438 nm under ultrasonic vibration. We also observed an effective reduction of AgNps by color hue changes in the colloidal dispersions, ranging from pale to dark yellow. Interestingly, the zeta potential values for the AgNps changed from -8.5 to -45.7 mV after incorporation with iota-carrageenan. Moreover, iota-carrageenan reduced the average particle sizes of AgNps/iota-carrageenan nanocomposite particles. Fourier transform infrared (FTIR) spectra proved the successful fabrication of AgNps/iota-carrageenan/cotton nanocomposites by shifting two bands at 3257 and 990 cm-1. Quantum Chemistry and Molecular Dynamics demonstrated strong interactions between AgNps and iota-carrageenan by changes in the bond lengths for CC, CH, CO, SO. Furthermore, new energy levels were generated in iota-carrageenan's molecules by exciting electrons under ultrasonic vibration. According to the thermal gravimetric analysis (TGA) results, fabrication of AgNps/iota-carrageenan on cotton reduced the thermal stability of the resultant AgNps/iota-carrageenan/cotton nanocomposites. The average friction coefficient values of nanocomposite samples were increased in weft-to-warp direction that can be an advantage for wound healing, antimicrobial treatment and drug delivery applications. We did not observe reduction in the mechanical properties of our AgNps incorporated nanocomposites. Furthermore, the samples were tested for possible cytotoxicity against primary human skin fibroblast cells and no toxicity was observed.


Assuntos
Materiais Biocompatíveis/química , Pesquisa Biomédica/métodos , Carragenina/química , Fibra de Algodão , Nanocompostos/química , Prata/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Escherichia coli/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Humanos , Camundongos , Microscopia Eletrônica de Varredura , Nanocompostos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Ondas Ultrassônicas , Difração de Raios X
10.
Int J Biol Macromol ; 180: 510-522, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33745975

RESUMO

In this work, 2,2,6,6-tetramethylpiperidine-1-oxyl-oxidized cellulose nanocrystals (TOCNs) were loaded into sodium alginate/chitosan multilayer film as nanofillers to investigate the modulation of the surface charge density of TOCNs on the film properties. First, the surface charge density of TOCNs was controlled by adjusting the carboxyl content and morphological size by varying the oxidant dosage. After oxidation, TOCN with higher surface charge density was observed to display a higher crystallinity, a more open internal structure, a better dispersibility and a slightly weaker thermal stability. In addition, a 15-layer film composed of sodium alginate and chitosan, called (SA/CH)15, was constructed by layer-by-layer assembly. Both in situ deposition monitoring and free-standing multilayer film formation indicated that TOCNs relied on strong electrostatic interactions and hydrogen bonding to achieve a compact and uniform interlayer and a thinner thickness of (SA/CH)15, which was more evident at a high surface charge density. The addition of TOCNs also enhanced the mechanical properties, thermal stability, hydrophobicity, and barrier properties of (SA/CH)15. In particular, the resulting sodium alginate/chitosan multilayer film exhibited an improved packaging performance when nanocomposite was performed using TOCN with a surface charge density of 3.22 ± 0.11 e nm-2.


Assuntos
Alginatos/química , Celulose/química , Quitosana/química , Nanofibras/química , Nanopartículas/química , Celulose Oxidada , Interações Hidrofóbicas e Hidrofílicas , Fenômenos Mecânicos , Microscopia Eletrônica de Transmissão , Nanocompostos/química , Nanocompostos/ultraestrutura , Nanofibras/ultraestrutura , Nanopartículas/ultraestrutura , Oxirredução , Espalhamento a Baixo Ângulo , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Propriedades de Superfície , Difração de Raios X
11.
Int J Biol Macromol ; 180: 523-532, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33745976

RESUMO

Nano silica (SiO2) is usually used as a common reinforcing agent in polymer materials, in which the interfacial interaction greatly affects the mechanical properties of the composites. The reinforcement effect of silica on non-polar polymer is restricted due to their poor compatibility. In this work, amphipathic lignin modified by quaternization and alkylation was used as a modifier for silica to prepare hydrophobic lignin/SiO2 nanoparticles by in-situ one-pot co-precipitation method. In alkaline solution, hydrophobic lignin and SiO2 (from Na2SiO3) were self-assembled to form nanospheres through electrostatic and hydrophobic interactions. The results showed that the lignin/SiO2 nanoparticles were highly hydrophobic nanospheres with macropores in the surface. When the lignin/SiO2 nanoparticles (10 wt%) were added to reinforce high-density polyethylene (HDPE), the mechanical properties of HDPE were improved with the strength of 24.5 MPa and the elongation of 1096%, which were increased by 10.4% and 14.3% compared with the control HDPE, because of the good compatibility and large bonding area. This work puts forward a new solution for the application of lignin in reinforcement of non-polar polymers.


Assuntos
Lignina/química , Nanocompostos/química , Nanopartículas/química , Polietileno/química , Dióxido de Silício/química , Álcalis/química , Interações Hidrofóbicas e Hidrofílicas , Fenômenos Mecânicos , Microscopia Eletrônica de Varredura , Modelos Químicos , Estrutura Molecular , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Propriedades de Superfície , Difração de Raios X
12.
Int J Biol Macromol ; 180: 709-717, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33771545

RESUMO

The fabrication of pectin-cellulose nanocrystal (CNC) biocomposites has been systematically investigated by blending both polysaccharides at different relative concentrations. Circular free-standing films with a diameter of 9 cm were prepared by simple solution of these carbohydrates in water followed by drop-casting and solvent evaporation. The addition of pectin allows to finely tune the properties of the biocomposites. Textural characterization by AFM showed fibrous morphology and an increase in fiber diameter with pectin content. XRD analysis demonstrated that pectin incorporation also reduced the degree of crystallinity though no specific interaction between both polysaccharides was detected, by ATR-FTIR spectroscopy. The optical properties of these biocomposites were characterized for the first time and it was found that pectin in the blend reduced the reflectance of visible light and increased UV absorbance. Thermal stability, analyzed by TGA, was improved with the incorporation of pectin. Finally, pectin-cellulose nanocrystal biocomposites showed a good biodegradability in seawater, comparable to other common bioplastics such as cellulose and low-molecular weight polylactide, among others.


Assuntos
Celulose/química , Nanocompostos/química , Nanopartículas/química , Pectinas/química , Hidrólise , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Nanocompostos/ultraestrutura , Nanopartículas/ultraestrutura , Fenômenos Físicos , Polissacarídeos/química , Água do Mar/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
13.
Int J Biol Macromol ; 181: 313-321, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33766601

RESUMO

This work offers a facile fabrication method for lignin nanocomposites through the assembly of kraft lignin onto magnetic nanoparticles (Fe3O4) based on pH-driven precipitation, without needing organic solvents or lignin functionalization. Kraft lignin@Fe3O4 multicore nanocomposites fabrication proceeded using a simple, pH-driven precipitation technique. An alkaline solution for kraft lignin (pH 12) was rapidly injected into an aqueous-based Fe3O4 nanoparticle colloidal suspension (pH 7) under constant mixing conditions, allowing the fabrication of lignin magnetic nanocomposites. The effects of increasing lignin to initial Fe3O4 mass content (g/g), increasing in ratio from 1:1 to 20:1, are discussed with a complete chemical, structural, and morphological characterization. Results showed that nanocomposites fabricated above 5:1 lignin:Fe3O4 had the highest lignin coverage and content (>20%), possessed superparamagnetic properties (Ms ≈ 45,000 A·m2/kg2); had a negative surface charge (-30 mV), and formed multicore nanostructures (DH ≈ 150 nm). The multicore lignin@Fe3O4 nanocomposites allowed rapid magnetically induced separations from suspension. After 5 min exposure to a rare-earth neodymium magnet (1.27 mm × 1.27 mm × 5.08 mm), lignin@Fe3O4 nanocomposites exhibited a maximum methylene blue removal efficiency of 74.1% ± 7.1%. These nanocomposites have potential in magnetically induced separations to remove organic dyes, heavy metals, or other lignin adsorbates.


Assuntos
Precipitação Química , Compostos Férricos/química , Lignina/química , Nanocompostos/química , Coloides/química , Concentração de Íons de Hidrogênio , Fenômenos Magnéticos , Nanocompostos/ultraestrutura , Tamanho da Partícula , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Suspensões , Difração de Raios X
14.
Int J Biol Macromol ; 181: 150-159, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33775755

RESUMO

Herein we report on a facile and green strategy for continuous production of chitosan-zinc oxide fibers and then compare their photodegradation performance against three organic dyes (i.e., methylene blue (MB), methyl orange (MO) and Rhodamine B, respectively) under different lights. Chitosan-zinc hydrogel fibers (CS/Zn) with different zinc loadings are obtained by direct mixing of chitosan and zinc acetate solutions using a double-syringe injection device. The as-prepared CS/Zn fibers are then immersed into glutaraldehyde (GA) and sodium hydroxide solutions, respectively, and dried at T = 50 °C. The resultant CS/ZnO/GA fibers of ca. 617 µm in diameter are characterized using X-ray diffraction (XRD), thermogravimetric analysis and field emission scanning electron microscope (FE-SEM). XRD and FE-SEM data confirm that the CS/ZnO/GA fibers consist of a large amount of hexagonal wurtzite ZnO nanorods up to 550 nm in length, and exhibit three-dimensional interconnected macroporous architecture. Photodegradation results clearly show that the CS/ZnO/GA fibers are effective for the removal of organic dyes upon UV irradiation and can be easily recovered and reused for at least 6 consecutive cycles. Unlike most reported CS/ZnO nanocomposites, the current CS/ZnO/GA fiber shows a higher adsorption of cationic MB rather than anionic MO, the mechanism of which is proposed.


Assuntos
Quitosana/química , Corantes/química , Corantes/efeitos da radiação , Luz , Compostos Orgânicos/química , Óxido de Zinco/química , Compostos Azo/química , Compostos Azo/efeitos da radiação , Catálise/efeitos da radiação , Glutaral/química , Azul de Metileno/química , Azul de Metileno/efeitos da radiação , Nanocompostos/química , Nanocompostos/ultraestrutura , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Raios Ultravioleta , Difração de Raios X
15.
Int J Nanomedicine ; 16: 775-788, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33574665

RESUMO

Background: Intracerebral hemorrhage (ICH) is a common neurological crisis leading to high mortality and morbidity. Oxidative stress-induced secondary injury plays a critical role in neurological deterioration. Previously, we synthesized a porous Se@SiO2 nanocomposite and identified their therapeutic role in osteonecrosis of the femoral head. Whether this nanocomposite is neuroprotective remains to be elucidated. Methods: A porous Se@SiO2 nanocomposite was synthesized, and its biosafety was determined using a CCK-8 assay. The neuroprotective effect was evaluated by TUNEL staining, and intracellular ROS were detected with a DCFH-DA probe in SH-SY5Y cells exposed to hemin. Furthermore, the effect of the nanocomposite on cell apoptosis, brain edema and blood-brain barrier permeability were evaluated in a collagenase-induced ICH mouse model. The potential mechanism was also explored. Results: The results demonstrated that Se@SiO2 treatment significantly improved neurological function, increased glutathione peroxidase activity and downregulated malonaldehyde levels. The proportion of apoptotic cells, brain edema and blood-brain barrier permeability were reduced significantly in ICH mice treated with Se@SiO2 compared to vehicle-treated mice. In vitro, Se@SiO2 protected SH-SY5Y cells from hemin-induced apoptosis by preventing intracellular reactive oxygen species accumulation. Conclusion: These results suggested that the porous Se@SiO2 nanocomposite exerted neuroprotection by suppressing oxidative stress. Se@SiO2 may be a potential candidate for the clinical treatment of ICH and oxidative stress-related brain injuries.


Assuntos
Encéfalo/patologia , Hemorragia Cerebral/patologia , Nanocompostos/química , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Selênio/farmacologia , Animais , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Biomarcadores/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/patologia , Encéfalo/efeitos dos fármacos , Edema Encefálico/complicações , Edema Encefálico/tratamento farmacológico , Linhagem Celular Tumoral , Hemorragia Cerebral/complicações , Hemorragia Cerebral/tratamento farmacológico , Citoproteção/efeitos dos fármacos , Modelos Animais de Doenças , Hemina/toxicidade , Humanos , Masculino , Malondialdeído/metabolismo , Camundongos Endogâmicos C57BL , Nanocompostos/toxicidade , Nanocompostos/ultraestrutura , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/farmacologia , Selênio/uso terapêutico , Dióxido de Silício/farmacologia , Testes de Toxicidade
16.
Sci Rep ; 11(1): 30, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33420103

RESUMO

Cadmium Oxide nanoparticles have the lowest toxicity when compared to nanoparticles of other semiconductors and they are not detrimental to human and mammalian cells, thereby making them candidates for targeting cancer cells. Synadenium cupulare plant extracts were used to synthesize CdO/CdCO3 nanocomposite using cadmium nitrate tetrahydrate 98% as a precursor salt. The resultant nanoparticles were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy, ultraviolet visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The nanoparticles were then screened for effect on breast cancer cell lines (MCF-7 and MDA MB-231) and Vero cell line to determine their growth inhibition effect. Cytotoxicity effect was evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. XRD showed the peaks of monteponite CdO and otavite CdCO3 nanoparticles. TEM results showed irregular and spherical particles of varying sizes, whilst SEM revealed a non-uniform morphology. FTIR results showed peaks of functional groups which are present in some of the phytochemical compounds found in S. cupulare, and point to the presence of CdO. Annealed CdO/CdCO3 NPs showed selectivity for MCF7 and MDA MB231 in comparison to Vero cell line, thereby supporting the hypothesis that cadmium oxide nanoparticles inhibit growth of cancerous cells more than non-cancerous cells.


Assuntos
Neoplasias da Mama/tratamento farmacológico , Nanocompostos/química , Nanocompostos/uso terapêutico , Pontos Quânticos/química , Pontos Quânticos/uso terapêutico , Animais , Neoplasias da Mama/patologia , Cádmio/química , Compostos de Cádmio/química , Carbonatos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Chlorocebus aethiops , Feminino , Humanos , Células MCF-7 , Magnoliopsida/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Nanocompostos/ultraestrutura , Óxidos/química , Espectroscopia Fotoeletrônica , Extratos Vegetais/química , Pontos Quânticos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Células Vero , Difração de Raios X
17.
Molecules ; 26(2)2021 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-33440910

RESUMO

Graphene and phospholipids are widely used in biosensing and drug delivery. This paper studies the mechanical and electronic properties of a composite based on two graphene flakes and dipalmitoylphosphatidylcholine (DPPC) phospholipid molecules located between them via combination of various mathematical modeling methods. Molecular dynamics simulation showed that an adhesion between bilayer graphene and DPCC increases during nanoindentation of the composite by a carbon nanotube (CNT). Herewith, the DPPC molecule located under a nanotip takes the form of graphene and is not destroyed. By the Mulliken procedure, it was shown that the phospholipid molecules act as a "buffer" of charge between two graphene sheets and CNT. The highest values of electron transfer in the graphene/DPPC system were observed at the lower indentation point, when the deflection reached its maximum value.


Assuntos
1,2-Dipalmitoilfosfatidilcolina/química , Grafite/química , Nanocompostos/química , Elétrons , Simulação de Dinâmica Molecular , Nanocompostos/ultraestrutura , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Estresse Mecânico
18.
J Chromatogr A ; 1638: 461889, 2021 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-33485030

RESUMO

As a typical steroid hormone drug, estradiol (E2) is also one of the most frequently detected endocrine disrupting chemicals (EDCs) in the aquatic environment. Herein, in response to the potential risk of E2 in steroid hormone pharmaceutical industry wastewater to human and wildlife, a novel carbon nanotubes / amine-functionalized Fe3O4 (CNTs/MNPs@NH2) nanocomposites with magnetic responsive have been developed for the enrichment and extraction of E2 in pharmaceutical industry wastewater, where amino-functionalized Fe3O4 magnetic nanoparticles (MNPs@NH2) were used as a magnetic source. The resultant CNTs/MNPs@NH2 possessed both the features of CNTs and desired magnetic property, enabling to rapidly recognize and separate E2 from pharmaceutical industry wastewater. Meanwhile, the CNTs/MNPs@NH2 had good binding behavior toward E2 with fast binding kinetics and high adsorption capacity, as well as exhibited satisfactory selectivity to steroidal estrogen compounds. Furthermore, the change of pH value of aqueous phase in adsorption solvent hardly affected the adsorption of E2 by CNTs/MNPs@NH2, and the adsorption capacity of E2 ranged from 19.9 to 17.2 mg g-1 in the pH range of 3.0 to 11.0, which is a latent advantage of the follow-up development method to detect E2 in pharmaceutical industry wastewater. As a result, the CNTs/MNPs@NH2 serving as a solid phase extraction medium were successfully applied to efficiently extract E2 from pharmaceutical industry wastewater. Therefore, the CNTs/MNPs@NH2 nanocomposites could be used as a potential adsorbent for removing steroidal estrogens from water. More importantly, the developed method would provide a promising solution for the monitoring and analysis of EDCs in pharmaceutical industry wastewater.


Assuntos
Aminas/química , Indústria Farmacêutica , Estradiol/isolamento & purificação , Compostos Férricos/química , Nanocompostos/química , Nanotubos de Carbono/química , Águas Residuárias/química , Adsorção , Aerobiose , Anaerobiose , Estradiol/análise , Humanos , Cinética , Magnetismo , Nanocompostos/ultraestrutura , Reprodutibilidade dos Testes , Extração em Fase Sólida , Solventes/química , Temperatura , Águas Residuárias/análise
19.
Carbohydr Polym ; 256: 117525, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33483046

RESUMO

Microfibrillated cellulose (MFC) is widely used as a reinforcement filler for biocomposites due to its unique properties. However, the challenge of drying MFC and the incompatibility between nanocellulose and polymer matrix still limits the mechanical performance of MFC-reinforced biocomposites. In this study, we used a water-based transesterification reaction to functionalize MFC and explored the capability of oven-dried MFC as a reinforcement filler for polylactic acid (PLA). Remarkably, this oven-dried, vinyl laurate-modified MFC improved the tensile strength by 38 % and Young's modulus by 71 % compared with neat PLA. Our results suggested improved compatibility and dispersion of the fibrils in PLA after modification. This study demonstrated that scalable water-based surface modification and subsequent straightforward oven drying could be a facile method for effectively drying cellulose nanomaterials. The method helps significantly disperse fibrils in polymers and enhances the mechanical properties of microfibrillar cellulose-reinforced biocomposites.


Assuntos
Celulose/química , Lauratos/química , Nanocompostos/química , Poliésteres/química , Compostos de Vinila/química , Varredura Diferencial de Calorimetria , Celulose/ultraestrutura , Dessecação/métodos , Módulo de Elasticidade , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanocompostos/ultraestrutura , Propriedades de Superfície , Resistência à Tração , Termogravimetria , Água/química
20.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499359

RESUMO

Carbonized elastomer-based composites (CECs) possess a number of attractive features in terms of thermomechanical and electromechanical performance, durability in aggressive media and facile net-shape formability, but their relatively low ductility and strength limit their suitability for structural engineering applications. Prospective applications such as structural elements of micro-electro-mechanical systems MEMS can be envisaged since smaller principal dimensions reduce the susceptibility of components to residual stress accumulation during carbonization and to brittle fracture in general. We report the results of in situ in-SEM study of microdeformation and fracture behavior of CECs based on nitrile butadiene rubber (NBR) elastomeric matrices filled with carbon and silicon carbide. Nanostructured carbon composite materials were manufactured via compounding of elastomeric substance with carbon and SiC fillers using mixing rolling mill, vulcanization, and low-temperature carbonization. Double-edge notched tensile (DENT) specimens of vulcanized and carbonized elastomeric composites were subjected to in situ tensile testing in the chamber of the scanning electron microscope (SEM) Tescan Vega 3 using a Deben microtest 1 kN tensile stage. The series of acquired SEM images were analyzed by means of digital image correlation (DIC) using Ncorr open-source software to map the spatial distribution of strain. These maps were correlated with finite element modeling (FEM) simulations to refine the values of elastic moduli. Moreover, the elastic moduli were derived from unloading curve nanoindentation hardness measurements carried out using a NanoScan-4D tester and interpreted using the Oliver-Pharr method. Carbonization causes a significant increase of elastic moduli from 0.86 ± 0.07 GPa to 14.12 ± 1.20 GPa for the composite with graphite and carbon black fillers. Nanoindentation measurements yield somewhat lower values, namely, 0.25 ± 0.02 GPa and 9.83 ± 1.10 GPa before and after carbonization, respectively. The analysis of fractography images suggests that crack initiation, growth and propagation may occur both at the notch stress concentrator or relatively far from the notch. Possible causes of such response are discussed, namely, (1) residual stresses introduced by processing; (2) shape and size of fillers; and (3) the emanation and accumulation of gases in composites during carbonization.


Assuntos
Elastômeros/química , Nanocompostos/química , Carbono/química , Compostos Inorgânicos de Carbono/química , Simulação por Computador , Módulo de Elasticidade , Análise de Elementos Finitos , Dureza , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanocompostos/ultraestrutura , Compostos de Silício/química , Estresse Mecânico , Resistência à Tração
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