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1.
PLoS One ; 19(8): e0307485, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39172972

RESUMEN

In this study, we present a novel approach to injection molding, focusing on the strength of weld lines in polyamide 6 (PA6) composite samples. By implementing a mold temperature significantly higher than the typical molding practice, which rarely exceeds 100°C, we assess the effects of advanced mold temperature management. The research introduces a newly engineered mold structure specifically designed for localized mold heating, distinguishing it as the 'novel cavity.' This innovative design is compared against traditional molding methods to highlight the improvements in weld line strength at elevated mold temperatures. To optimize the molding parameters, we apply an Artificial Neural Network (ANN) in conjunction with a Genetic Algorithm (GA). Our findings reveal that the optimal ultimate tensile strength (UTS) and elongation values are achieved with a filling time of 3.4 seconds, packing time of 0.8 seconds, melt temperature of 246°C, and a novel high mold temperature of 173°C. A specific sample demonstrated the best molding parameters at a filling time of 3.4 seconds, packing time of 0.4 seconds, melt temperature of 244°C, and mold temperature of 173°C, resulting in an elongation value of 582.6% and a UTS of 62.3 MPa. The most influential factor on the PA6 sample's UTS and elongation at the weld line was found to be the melt temperature, while the filling time had the least impact. SEM analysis of the fracture surfaces revealed ductile fractures with rough surfaces and grooves, indicative of the weld line areas' bonding quality. These insights pave the way for significant improvements in injection molding conditions, potentially revolutionizing the manufacturing process by enhancing the structural integrity of the weld lines in molded PA6 samples.


Asunto(s)
Nylons , Nylons/química , Temperatura , Resistencia a la Tracción , Redes Neurales de la Computación , Gases/química , Plásticos/química , Ensayo de Materiales , Caprolactama/química , Caprolactama/análogos & derivados , Algoritmos , Polímeros
2.
Sci Rep ; 14(1): 15450, 2024 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-38965403

RESUMEN

Ghost fishing is a global issue that can be addressed using fishing gear materials that do not persist in the marine environment. However, for these alternatives to be widely adopted, they must meet the same mechanical specifications as current commercial materials while degrading without any negative impact. The objective of this study was to compare a conventional gillnet made of polyamide 6 (PA6) with an alternative made of poly(butylene succinate-co-adipate-co-terephthalate) (PBSAT) at three different scales: monofilament, knot, and net. While the PBSAT monofilament's strength was half that of the conventional PA6 net, knot and net losses were even more significant. This indicates a greater sensitivity of the material to the knot. Since the results between the knot and net scales were coherent, testing whole net panels is not necessary. Studying the curvature and the behaviour of the knot revealed its complex geometry and mechanical behaviour. Testing the weaver's knot is a good indicator for studying the relevance of an alternative to conventional fishing gear materials. This should be considered when developing biodegradable nets in order to reduce ghost fishing at sea.


Asunto(s)
Ensayo de Materiales , Polímeros/química , Poliésteres/química , Explotaciones Pesqueras , Caprolactama/análogos & derivados , Caprolactama/química , Resistencia a la Tracción
3.
PLoS One ; 19(7): e0304823, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39074083

RESUMEN

Polyamide 12 (PA12) is vastly utilized in many additive manufacturing methods, such as Selective Laser Sintering (SLS), and a better understanding of its mechanical behaviors promotes available knowledge on the behaviors of 3D-printed parts made from this polymer. In this paper, SLS-produced standard tensile specimens are studied under monotonic and cyclic tension tests, as well as stress relaxation experiments, and the obtained force-displacement responses are shown to be consistent with a hyper-viscoelastic material model. This finding is also observed in typical pantographic structures produced by the same manufacturing parameters. To propose a constitutive model for predicting these behaviors, the convolution integral of a strain-dependent function and a time-dependent function is developed where the material parameters are determined with the use of both short-term and long-term responses of the specimens. Numerical results of the presented model for standard test specimens are shown to be in good agreements with the experimental ones under various loading conditions. To prove the capabilities of the proposed model in studying any SLS-produced part, finite element implementation of the constitutive equations is shown to provide numerical results in agreement with the empirical findings for tensile loading of the 3D-printed pantographic structure.


Asunto(s)
Elasticidad , Rayos Láser , Resistencia a la Tracción , Viscosidad , Impresión Tridimensional , Ensayo de Materiales , Estrés Mecánico , Análisis de Elementos Finitos , Modelos Teóricos , Caprolactama/química , Caprolactama/análogos & derivados , Nylons/química , Polímeros/química
4.
Food Chem ; 451: 139368, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-38657518

RESUMEN

A unique strategy for developing porous membrane protected micro-solid phase extraction has been provided. An electrospun composite was fabricated on the sheet of membrane. To this end, NiFe-layered double hydroxide/Nylon 6 composite nanofibers were coated on a polypropylene membrane sheet followed by folding into a pocket shape, which were then utilized as a novel extractive device to extract of organophosphorus pesticides from fresh fruit juice samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The fabricated hybrid composites were successfully characterized. The effective parameters on extraction performance were investigated. LODs were 0.020-0.065 ng mL-1. Excellent linearity (R2≥0.996) was observed between 0.05 and 100.0 ng mL-1. RSDs% were in the range of 3.1-5.8% (intra-day, n = 3) and 2.6-5.5% (inter-day, n = 3×3). Satisfactory related recovery values within the acceptable range of 90.7-111.2% with RSDs% below 6.7% were achieved for the analysis of real samples.


Asunto(s)
Caprolactama , Jugos de Frutas y Vegetales , Polímeros , Polipropilenos , Microextracción en Fase Sólida , Espectrometría de Masas en Tándem , Jugos de Frutas y Vegetales/análisis , Polipropilenos/química , Microextracción en Fase Sólida/instrumentación , Microextracción en Fase Sólida/métodos , Polímeros/química , Caprolactama/química , Caprolactama/análogos & derivados , Plaguicidas/aislamiento & purificación , Plaguicidas/química , Contaminación de Alimentos/análisis , Compuestos Organofosforados/aislamiento & purificación , Compuestos Organofosforados/química , Compuestos Organofosforados/análisis , Níquel/química , Níquel/aislamiento & purificación , Porosidad , Cromatografía Liquida/instrumentación , Extracción en Fase Sólida/instrumentación , Extracción en Fase Sólida/métodos
5.
Acta Chim Slov ; 69(2): 251-260, 2022 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-35861067

RESUMEN

Soft nanoparticles are an important class of material with potential to be used as carriers of active compounds. Swollen, penetrable particles can act as a host for the active ingredients and provide stability, stimuli-responsiveness and recyclability for the guest. Thermoresponsive colloidal gel particles are especially attractive for such applications due to the extremely soft structure, size and responsiveness. Poly(N-vinylcaprolactam) (PNVCL) is a much studied, popular thermoresponsive polymer. The polymer has low toxicity and the phase transition temperature is close to body temperature. During the phase transition, the polymer becomes less soluble, the particle expels a large part of water and the particle collapses to a more compact form. The diffusion of material in and from the particles is largely affected by this transition.  As the solubility of the polymer changes, so do the interactions with the loaded compound.  This feature article focuses on the synthetic methods, properties and applications of soft PNVCL particles.


Asunto(s)
Caprolactama , Caprolactama/análogos & derivados , Caprolactama/química , Polímeros/química , Temperatura , Agua/química
6.
J Mater Chem B ; 10(19): 3723-3733, 2022 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-35451441

RESUMEN

In analogy with adsorbed protein films, we have fabricated a family of 2D nanofilms composed of poly(N-vinyl caprolactam-co-vinylimidazole) (PNVCL) nanogels. NVCL was copolymerized with 1-vinylimidazole (VIM), and then cross-linked with α,ω-dibromoalkanes with 2 to 8 carbons via quaternization to form the nanogels. The swelling ratio of the gels was precisely controlled by regulating the inter-chain spacing of the polymers at the level of the carbon atom chain length of the cross-linker. The short-chain alkanes used are relatively rigid and their dimensions provide an accurate estimate of the chain spacing in the nanogels. It was shown that small differences in the carbon atom number of the cross-linking agent led to significant differences in the mechanical properties of the nanogels, in particular in the softness, deformability, and contact area (in film form), all of which increased with increasing carbon number. Films of the softer gels not only showed good adhesion to a number of substrates, but were also mechanically robust. In addition, the films showed excellent light transmission and nontoxicity to L929 cells. Nanogels of intermediate softness were shown to inhibit the adhesion of bacteria and human umbilical vein smooth muscle cells (HUVSMCs), and to be resistant to the adsorption of the plasma protein fibrinogen, indicating strong anti-biofouling properties. Gels that were either too stiff or too soft showed somewhat weaker anti-fouling activity in terms both of HUVSMCs adhesion and protein adsorption.


Asunto(s)
Incrustaciones Biológicas , Caprolactama , Incrustaciones Biológicas/prevención & control , Caprolactama/química , Carbono , Humanos , Hidrogeles , Imidazoles , Nanogeles , Polímeros/química
7.
Int J Biol Macromol ; 194: 358-365, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34800520

RESUMEN

To expand the field of high-value utilization of lignin. The degraded deep eutectic solvent lignin-grafted poly (N-Vinyl caprolactam) (DES-lignin-g-PNVCL) was synthesized by modified DES-lignin and NVCL via the combination of activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP). Fourier transform infrared spectroscopy (FT-IR), 1H NMR, X-ray electron spectroscopy (XPS), dynamic light scattering (DLS), differential scanning calorimeter (DSC) were used to characterize the structure and performance of DES-lignin-g-PNVCL. The results indicated that the PNVCL and DES-lignin-g-PNVCL were successfully prepared by ARGET-ATRP. The lowest critical solution temperature (LCST) of PNVCL was 35.75 °C. Due to different strength of hydrogen bond, different energies were required, so the LCST of the polymer can be regulated. When the molar ratio of phenolic hydroxyl group in degraded DES-lignin to 2-bromoisobutyryl bromide (BiBB) was increased from 1:1 to 1:7, the grafting rate of DES-lignin-Br was increased from 32.87% to 60.84%, and the LCST of DES-lignin-g-PNVCL was decreased from 47.98 °C to 27.88 °C. The LCST of DES-lignin-g-PNVCL was increased from 30.98 °C to 44.64 °C when the addition amount of DES-lignin-Br was increased from 20 mg to 200 mg. The LCST of DES-lignin-g-PNVCL was increased from 27.20 °C to 39.86 °C when the ratio of DMF/water was increased from 1:4 to 4:1. The LCST of DES-lignin-g-PNVCL was decreased from 52.10 °C to 31.02 °C when the concentration of DES-lignin-g-PNVCL was increased from 0.5 mg/mL to 2.5 mg/mL. The equation represented the relationship between LCST and influencing factors was obtained, the good predictability provided a tactics for preparing desired LCST thermo-responsible polymer.


Asunto(s)
Caprolactama/análogos & derivados , Disolventes Eutécticos Profundos/química , Lignina/química , Polímeros/química , Rastreo Diferencial de Calorimetría , Caprolactama/síntesis química , Caprolactama/química , Fenómenos Químicos , Técnicas de Química Sintética , Dispersión Dinámica de Luz , Estructura Molecular , Polimerizacion , Polímeros/síntesis química , Espectroscopía Infrarroja por Transformada de Fourier
8.
Proteins ; 89(9): 1079-1098, 2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-33826169

RESUMEN

Caprolactamase is the first enzyme in the caprolactam degradation pathway of Pseudomonas jessenii. It is composed of two subunits (CapA and CapB) and sequence-related to other ATP-dependent enzymes involved in lactam hydrolysis, like 5-oxoprolinases and hydantoinases. Low sequence similarity also exists with ATP-dependent acetone- and acetophenone carboxylases. The caprolactamase was produced in Escherichia coli, isolated by His-tag affinity chromatography, and subjected to functional and structural studies. Activity toward caprolactam required ATP and was dependent on the presence of bicarbonate in the assay buffer. The hydrolysis product was identified as 6-aminocaproic acid. Quantum mechanical modeling indicated that the hydrolysis of caprolactam was highly disfavored (ΔG0 '= 23 kJ/mol), which explained the ATP dependence. A crystal structure showed that the enzyme exists as an (αß)2 tetramer and revealed an ATP-binding site in CapA and a Zn-coordinating site in CapB. Mutations in the ATP-binding site of CapA (D11A and D295A) significantly reduced product formation. Mutants with substitutions in the metal binding site of CapB (D41A, H99A, D101A, and H124A) were inactive and less thermostable than the wild-type enzyme. These residues proved to be essential for activity and on basis of the experimental findings we propose possible mechanisms for ATP-dependent lactam hydrolysis.


Asunto(s)
Adenosina Trifosfato/química , Amidohidrolasas/química , Proteínas Bacterianas/química , Caprolactama/química , Subunidades de Proteína/química , Pseudomonas/enzimología , Adenosina Trifosfato/metabolismo , Amidohidrolasas/genética , Amidohidrolasas/metabolismo , Secuencia de Aminoácidos , Ácido Aminocaproico/química , Ácido Aminocaproico/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sitios de Unión , Caprolactama/metabolismo , Clonación Molecular , Cristalografía por Rayos X , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Hidrólisis , Modelos Moleculares , Mutación , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Multimerización de Proteína , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Pseudomonas/química , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Relación Estructura-Actividad , Especificidad por Sustrato , Termodinámica
9.
Molecules ; 26(5)2021 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-33807791

RESUMEN

In the present work, the thermochemistry of solution, solvation, and hydrogen bonding of cyclic amides in proton acceptor (B) and proton donor (RXH) solvents were studied. The infinite dilution solution enthalpies of δ-valerolactam, N-methylvalerolactam, ε-caprolactam, and N-methylcaprolactam were measured at 298.15 K. The solvation enthalpies of cyclic amides were calculated based on the measured solution enthalpies and sublimation/vaporization enthalpies from literature. The enthalpies of hydrogen bonding between cyclic amides and proton acceptor and donor solvents were then calculated as a difference between the total solvation enthalpy and the non-specific contribution. The latter was estimated via two different approaches in proton donor and proton accepting solvents. The effect of the cycle size on the strength of hydrogen bonding of the cyclic amides in solution is discussed.


Asunto(s)
Amidas/química , Lactamas/química , Solventes/química , Calorimetría , Caprolactama/química , Enlace de Hidrógeno , Piperidonas/química , Protones
10.
Carbohydr Polym ; 260: 117769, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33712127

RESUMEN

Periodontal defect poses a significant challenge in orthopedics. Guided Bone Regeneration (GBR) membrane is considered as one of the most successful methods applied to reconstruct alveolar bone and then to achieve periodontal defect repair/regeneration. In this paper, a novel polyamide-6/chitosan@nano-hydroxyapatite/polyamide-6 (PA6/CS@n-HA/PA6) bilayered tissue guided membranes by combining a solvent casting and an electrospinning technique was designed. The developed PA6/CS@n-HA/PA6 composites were characterized by a series of tests. The results show that n-HA/PA6 and electrospun PA6/CS layers are tightly bound by molecular interaction and chemical bonding, which enhances the bonding strength between two distinct layers. The porosity and adsorption average pore diameter of the PA6/CS@n-HA/PA6 membranes are 36.90 % and 22.61 nm, respectively. The tensile strength and elastic modulus of PA6/CS@n-HA/PA6 composites are 1.41 ± 0.18 MPa and 7.15 ± 1.09 MPa, respectively. In vitro cell culture studies demonstrate that PA6/CS@n-HA/PA6 bilayered scaffolds have biological safety, good bioactivity, biocompatibility and osteoconductivity.


Asunto(s)
Regeneración Ósea , Caprolactama/análogos & derivados , Quitosano/química , Durapatita/química , Membranas Artificiales , Nanoestructuras/química , Polímeros/química , Animales , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Regeneración Ósea/efectos de los fármacos , Caprolactama/química , Adhesión Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Ratones , Nanofibras/química , Nanoestructuras/toxicidad , Porosidad , Propiedades de Superficie , Resistencia a la Tracción
11.
Food Chem ; 350: 129260, 2021 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-33618093

RESUMEN

Oligomers, are, in general, unknown components of the polymer. These oligomers can migrate from the polymer into the food and become a non-intentionally added substance to the food. In this work, ion mobility time-of-flight mass spectrometry has been used to identify oligomers migrating from kitchenware. The structure elucidation of oligomers from polyamide 6 and polyamide 66 was achieved through the analysis of accurate m/z values of adducts and collision cross section values of precursor ions together with high-energy fragmentation patterns. Additionally, a method to extract oligomers from sunflower oil, cooked beans, soup and whole milk has been developed. Extraction recoveries ranged from 87 to 102% and limits of detection were from 0.03 to 0.11 mg/kg. It was observed that the migration from kitchenware to real food was below the specified migration limit of 5 mg/kg. However, this limit was exceeded for food simulants, which therefore overestimated the oligomer migration.


Asunto(s)
Caprolactama/análogos & derivados , Contaminación de Alimentos/análisis , Espectrometría de Movilidad Iónica/métodos , Polimerizacion , Polímeros/química , Animales , Caprolactama/química , Leche/química
12.
Biotechnol Bioeng ; 118(3): 1105-1115, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33241852

RESUMEN

Virus retention filtration is a common step in modern biopharmaceutical manufacturing as it enables efficient removal of potential adventitious and endogenous viruses via size exclusion. Modern parvovirus retention filters have significantly improved fluxes and parvovirus retention in comparison to earlier versions of these filters. However, these filters may be more susceptible to premature fouling and require more effort for process optimization. Here, we demonstrate that polyamide-6,6 (nylon-6,6) membranes when used as prefilters can increase the capacity of these Parvovirus retentive filters that are less susceptible to premature fouling. We found that the mechanism of polyamide-mediated filtration improvement can be explained by the binding of monoclonal antibody (mAb) aggregates with a diameter of 20-100 nm, and we show that this mechanism is shared by other types of adsorptive prefilters. Finally, by the combination of mobile phase screening, additive spiking, and molecular dynamics simulations, we show that polyamide-6,6 removes mAb aggregates through hydrophobic interactions making its design space potentially complementary to other available prefilters. Our studies support the aggregate-mediated mechanism of flux decay during viral filtration and suggest that polyamide-6,6 could be considered as an alternative cost-effective option to extend the capacity of viral filters.


Asunto(s)
Anticuerpos Monoclonales/química , Anticuerpos Antivirales/química , Caprolactama/análogos & derivados , Simulación de Dinámica Molecular , Parvovirus/química , Polímeros/química , Caprolactama/química , Filtración
13.
Biomed Mater ; 16(2): 025014, 2021 02 18.
Artículo en Inglés | MEDLINE | ID: mdl-33361571

RESUMEN

Polyamide-6 (PA6) is a synthetic polymer that bears resemblance to collagen in its backbone and has excellent stability in human body fluid. Chitosan (CS) with the similar structure to that of the polysaccharides existing in the extracellular matrix (ECM), has a more suitable biodegradation rate for the formation of new-bone. Electrospun fiber have nanoscale structure, high porosity and large specific surface area, can simulate the structure and biological function of the natural ECM. To meet the requirements of mechanical properties and biocompatibility of bone tissue engineering, electrospun PA6/CS scaffolds were fabricated by electrospinning technology. The mineralized PA6/CS scaffolds were obtained through immersion in 1.5× simulated body fluid (1.5SBF), which allowed the hydroxyapatite (HA) layer to grow into the thickness range under very mild reaction conditions without the need of a prior chemical modification of the substrate surface. The results showed that electrospun PA6/CS fibrous scaffolds in the diameter range of 60-260 nm mimic the nanostructure of the ECM. The tensile strength and modulus of 10PA6/CS fibrous scaffolds reach up to 12.67 ± 2.31 MPa and 95.52 ± 6.78 MPa, respectively. After mineralization, HA particles uniformly distributed on the surface of PA6/CS fibrous scaffolds in a porous honeycomb structure, and the content of mineral was about 40%. In addition, cell culture study indicated that the mineralized PA6/CS composite scaffolds were non-cytotoxic, and had a good biocompatibility and an ability to promote MC3T3-E1 cell attachment and proliferation.


Asunto(s)
Huesos/metabolismo , Caprolactama/análogos & derivados , Quitosano/química , Materiales Biocompatibles Revestidos/química , Durapatita/química , Polímeros/química , Ingeniería de Tejidos/métodos , Células 3T3 , Animales , Materiales Biocompatibles/química , Biomimética , Caprolactama/química , Adhesión Celular , Proliferación Celular , Supervivencia Celular , Colágeno/química , Ratones , Nanoestructuras/química , Osteoblastos/citología , Porosidad , Presión , Estrés Mecánico , Especificidad por Sustrato , Propiedades de Superficie , Resistencia a la Tracción , Andamios del Tejido/química
14.
J Sep Sci ; 43(22): 4216-4224, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32964564

RESUMEN

Priority pollutants chlorophenols are broadly used chemicals that are persistent in the environment and causing serious human health hazards. The current study introduces a novel adsorbent for the extraction of chlorophenols from river water, surface water, and milk by headspace solid-phase microextraction coupled with gas chromatography. The adsorbent composite was prepared by blending polycaprolactam (nylon-6) mat and newly synthesized carbon nanotubes decorated with cadmium oxide nanoparticles followed by electrospinning technique to produce based nanofiber. The proposed nanofiber was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques. The main parameters that affect extraction efficiency, including ionic strength, extraction time, desorption time, and extraction temperature, were investigated and optimized. The linear range was 0.05-5 ng/mL; the limits of detection (signal/noise=3) were 0.02-0.04 ng/mL. The relative recoveries for real samples (river water, surface water, and milk) were in the range of 84-114%.


Asunto(s)
Compuestos de Cadmio/química , Clorofenoles/análisis , Nanofibras/química , Nanotubos de Carbono/química , Óxidos/química , Microextracción en Fase Sólida , Contaminantes Químicos del Agua/análisis , Animales , Caprolactama/química , Leche/química , Tamaño de la Partícula , Polímeros/química , Agua/química
15.
J Mater Chem B ; 8(37): 8585-8598, 2020 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-32820296

RESUMEN

Injectable, drug-releasing hydrogel scaffolds with multifunctional properties including hemostasis and anti-bacterial activity are essential for successful wound healing; however, designing ideal materials is still challenging. Herein, we demonstrate the fabrication of a biodegradable, temperature-pH dual responsive supramolecular hydrogel (SHG) scaffold based on sodium alginate/poly(N-vinyl caprolactam) (AG/PVCL) through free radical polymerization and the subsequent chemical and ionic cross-linking. A natural therapeutic molecule, tannic acid (TA)-incorporated SHG (AG/PVCL-TA), was also fabricated and its hemostatic and wound healing efficiency were studied. In the AG/PVCL-TA system, TA acts as a therapeutic molecule and also substitutes as an effective gelation binder. Notably, the polyphenol-arm structure and diverse bonding abilities of TA can hold polymer chains through multiple bonding and co-ordinate cross-linking, which were vital in the formation of the mechanically robust AG/PVCL-TA. The SHG formation was successfully balanced by varying the composition of SA, VCL, TA and cross-linkers. The AG/PVCL-TA scaffold was capable of releasing a therapeutic dose of TA in a sustained manner under physiological temperature-pH conditions. AG/PVCL-TA displayed excellent free radical scavenging, anti-inflammatory, anti-bacterial, and cell proliferation activity towards the 3T3 fibroblast cell line. The wound healing performance of AG/PVCL-TA was further confirmed in skin excision wound models, which demonstrated the potential application of AG/PVCL-TA for skin regeneration and rapid wound healing.


Asunto(s)
Antibacterianos/uso terapéutico , Hemostasis/efectos de los fármacos , Hidrogeles/química , Taninos/uso terapéutico , Cicatrización de Heridas/efectos de los fármacos , Alginatos/química , Alginatos/toxicidad , Animales , Antibacterianos/química , Antibacterianos/toxicidad , Antiinflamatorios/química , Antiinflamatorios/uso terapéutico , Antiinflamatorios/toxicidad , Antioxidantes/química , Antioxidantes/uso terapéutico , Antioxidantes/toxicidad , Bacterias/efectos de los fármacos , Caprolactama/análogos & derivados , Caprolactama/química , Caprolactama/toxicidad , Movimiento Celular/efectos de los fármacos , Femenino , Hidrogeles/toxicidad , Concentración de Iones de Hidrógeno , Inflamación/tratamiento farmacológico , Ratones , Pruebas de Sensibilidad Microbiana , Células 3T3 NIH , Polímeros/química , Polímeros/toxicidad , Ratas Wistar , Piel/patología , Taninos/química , Taninos/toxicidad , Temperatura
16.
Carbohydr Polym ; 241: 116227, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-32507174

RESUMEN

The paper presents a novel candidate plant: Pandanus ceylanicus (PC) for cellulose extraction. The plant showed an average of 91.5 ±â€¯0.2 % of cellulose yield which is the highest yield for Pandanus species reported. Cellulose was extracted from the leaves of the plant by carrying out alkali and bleaching treatments, and cellulose microcrystals (CMC) were isolated from extracted cellulose fibers with sulphuric acid treatment. Chemical composition of PC leaves was investigated at different stages of treatment by using TAPPI standard methods. The extracted globular shaped CMC crystals had an average diameter less than a micro meter. Results revealed that PC leaves are an efficient source of micro-cellulose which result in a high yield than most lignocellulosic biomasses. The CMCs were successfully incorporated with nylon 6,10 by in-situ interfacial polymerization of sebacoyl chloride and hexamethylenediamine in the presence of CMC. The CMC/nylon 6,10 composite showed improved water absorption with low water retention time.


Asunto(s)
Caprolactama/análogos & derivados , Celulosa/química , Pandanaceae , Polímeros/química , Caprolactama/química , Hojas de la Planta/química , Ácidos Sulfúricos/química , Agua/química
17.
Mater Sci Eng C Mater Biol Appl ; 113: 110998, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32487406

RESUMEN

Silver-based nanomaterials are used as antibacterial agents in a number of applications, including wound dressing, where electrospun materials can effectively promote wound healing and tissue regeneration thanks to their biomimicry, flexibility and breathability. Incorporation of such nanomaterials in electrospun nonwovens is highly challenging if aiming at maximizing stability and antibacterial efficacy and minimizing silver detachment, without neglecting process straightforwardness and scalability. In this work nanostructured silver coatings were deposited by Ionized Jet Deposition (IJD) on Polylactic acid, a medical grade polyester-urethane and Polyamide 6,6 nanofibers. The resulting materials were thoroughly characterized to gain an in-depth view of coating morphology and substrate resistance to the low-temperature deposition process used. Morphology of silver coatings with well-cohesive grains having dimensions from a few tens to a few hundreds of nanometers was analyzed by SEM, TEM and AFM. TGA, DSC, FTIR and GPC showed that the polymers well withstand the deposition process with negligible effects on their properties, the only exception being the polylactic acid that resulted more susceptible to degradation. Finally, the efficacy against S. aureus and E. coli bacterial strains was demonstrated, indicating that electrospun fibers decorated with nanostructured silver by IJD represent a breakthrough solution in the field of antibacterial devices.


Asunto(s)
Antibacterianos/química , Nanofibras/química , Nanoestructuras/química , Polímeros/química , Plata/química , Antibacterianos/farmacología , Caprolactama/análogos & derivados , Caprolactama/química , Pruebas Antimicrobianas de Difusión por Disco , Escherichia coli/efectos de los fármacos , Nanoestructuras/toxicidad , Poliésteres/química , Staphylococcus aureus/efectos de los fármacos
18.
Mater Sci Eng C Mater Biol Appl ; 112: 110868, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32409037

RESUMEN

Biological meshes have always posed a challenge in biological medicine, for which nanocomposites with enhanced biocompatibility and antibacterial activity may be beneficial. In this study, lysozyme (LY) and collagen (Col) were alternately deposited on silk fibroin (SF) and nylon 6 (N6) composite nanofibrous mats using a layer-by-layer (LBL) self-assembly technique. The mechanical properties, biocompatibility, and antibacterial activity of the LBL structured mats were characterized systematically to investigate the impact of the LBL process on the biological properties of SF/N6 nanofibrous mats. Our results showed that the effective deposition of LY and Col may affect the surface topography, mechanical properties, and wetting behavior of the SF/N6 nanofibrous mats. Moreover, LBL structured mats exhibited excellent biocompatibility and antibacterial properties. Among all the tested mats, those coated with 10 bilayers of LY and Col displayed the best biocompatibility, and relatively good mechanical and antibacterial properties. Thus, LBL structured mats, especially those with a 10 bilayer coating, are potentially valuable in clinical therapy for pelvic organ prolapse in the future.


Asunto(s)
Antibacterianos/química , Materiales Biocompatibles/química , Colágeno/química , Muramidasa/química , Nanofibras/química , Animales , Antibacterianos/farmacología , Materiales Biocompatibles/farmacología , Caprolactama/análogos & derivados , Caprolactama/química , Adhesión Celular/efectos de los fármacos , Línea Celular , Módulo de Elasticidad , Escherichia coli/efectos de los fármacos , Fibroínas/química , Ratones , Nanofibras/toxicidad , Polímeros/química , Staphylococcus aureus/efectos de los fármacos , Resistencia a la Tracción
19.
Anal Chem ; 92(13): 8965-8973, 2020 07 07.
Artículo en Inglés | MEDLINE | ID: mdl-32436691

RESUMEN

In this work, a graphene oxide (GRO)-based temperature-sensitive smart catalytic support material was developed by tethering biodegradable and hydrophilic poly(N-vinylcaprolactam) (PVCL) on a GRO (i.e., GRO-PVCL) surface. GRO-PVCL-supported palladium catalyst (i.e., Pd/GRO-PVCL) was then prepared for tizanidine (TZN) electroreduction. The impact of a temperature-sensitive smart surface on the electrochemical and electrocatalytic properties was examined. Moreover, when the large surface area, excellent electron transfer, and electrochemical catalysis abilities of GRO were combined with the responsive characteristics of PVCL, temperature-triggered reversible electrocatalysis of TZN with enhanced sensitivity has been proved. Results designated that GRO-PVCL exposed the hydrophilic surface at 20 °C, resulting in Pd NPs highly dispersed on the GRO-PVCL surface. Subsequently, the wettability of the Pd catalyst surface arbitrarily adapted to hydrophobicity at 40 °C, which highly enhanced the TZN reduction on the catalyst in electrochemical detection. The synergistic effect amid Pd and GRO-PVCL on Pd/GRO-PVCL improved the electrocatalytic activity of TZN. The detection of TZN with the Pd/GRO-PVCL modified electrode ranged from 0.02 to 276 µM with a low detection limit of 0.0015 µM at 40 °C. The Pd/GRO-PVCL modified electrode also possesses excellent stability, reproducibility, and anti-interference ability. Lastly, the modified electrode attained good recovery results in human urine and human plasma samples for the determination of TZN and also pharmacokinetics study in rat plasma.


Asunto(s)
Clonidina/análogos & derivados , Técnicas Electroquímicas/métodos , Grafito/química , Paladio/química , Caprolactama/análogos & derivados , Caprolactama/química , Catálisis , Clonidina/análisis , Clonidina/química , Electrodos , Interacciones Hidrofóbicas e Hidrofílicas , Límite de Detección , Nanocompuestos/química , Polímeros/química , Reproducibilidad de los Resultados , Propiedades de Superficie , Temperatura
20.
Mater Sci Eng C Mater Biol Appl ; 109: 110549, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32228950

RESUMEN

Nature creates soft and hard ingredients revealing outstanding properties by adjusting the ordered assembly of simple primarily components from the nano- to the macro-scale. To simulate the important features of native tissue architecture, wide researches are being performed to develop new biomimetic custom-made composite scaffolds for tissue engineering. Here, we introduced a three-dimensional (3D) biomimetic scaffold based on the cuttlefish bone (CB) as a sacrificial template for bone tissue engineering. By combination of nylon 6 (N6), various amounts of baghdadite (BG) nanopowder and sacrificial template CB, a novel nanocomposite scaffolds was successfully developed with hierarchical microstructure and open pores in the range size in long and minor axis of 153-253 µm and 39-70 µm, respectively, depending on the BG content. In addition, incorporation of BG improved the mechanical properties of the scaffolds. Noticeably, the compressive strength and compressive modulus enhanced from 0.47 ± 0.05 to 1.41 ± 0.25 MPa and from 3.16 ± 0.14 to 6.23 ± 0.3 MPa, respectively. Moreover, results demonstrated that the incorporation of BG nanoparticles in the N6 matrix significantly improved bioactivity in simulated body fluid and increased degradation rate of N6 scaffold. Additionally, 3D nanocomposite scaffolds disclosed meaningfully excellent cellular responses. It is envisioned that the provided N6-BG nanocomposite scaffold might be a promising candidate for bone tissue engineering applications.


Asunto(s)
Materiales Biomiméticos/química , Huesos , Caprolactama/análogos & derivados , Cerámica/química , Nanocompuestos/química , Polímeros/química , Silicatos/química , Ingeniería de Tejidos , Andamios del Tejido/química , Caprolactama/química , Línea Celular Tumoral , Humanos
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