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1.
Carbohydr Polym ; 269: 118346, 2021 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-34294353

RESUMEN

In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO2 quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO2 vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO2 revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO2 and Ag/CNC-CeO2.


Asunto(s)
Antibacterianos/farmacología , Celulosa/química , Cerio/química , Colorantes/química , Puntos Cuánticos/química , Plata/farmacología , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/efectos de la radiación , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Catálisis/efectos de la radiación , Celulosa/síntesis química , Celulosa/metabolismo , Celulosa/efectos de la radiación , Cerio/metabolismo , Cerio/efectos de la radiación , Ciprofloxacina/química , Girasa de ADN/química , Girasa de ADN/metabolismo , Dihidropteroato Sintasa/química , Dihidropteroato Sintasa/metabolismo , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Luz , Azul de Metileno/química , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Unión Proteica , Puntos Cuánticos/metabolismo , Puntos Cuánticos/efectos de la radiación , Plata/química , Plata/metabolismo , Plata/efectos de la radiación , Staphylococcus aureus/efectos de los fármacos , Tetrahidrofolato Deshidrogenasa/química , Tetrahidrofolato Deshidrogenasa/metabolismo , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos
2.
Carbohydr Polym ; 268: 118235, 2021 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-34127218

RESUMEN

In-depth understanding of interfacial property is the key to guiding the synthesis of biomass composites with desired performance. However, the exploration is of great challenge due to limitations of experimental techniques in locating hydrogen, requiring large/good crystals and detecting a weak interaction like van der Waals (vdW). Herein, we experimentally and computationally investigated the composite cellulose/zinc oxide/g-C3N4. Hydrothermal synthesis afforded cellulose/ZnO, and then fabricated the ternary composite by adding g-C3N4 under ultrasonic condition. Three components are found to co-exist in the composite, and the ZnO nanoparticle is attaching to cellulose and coupling with g-C3N4. These experimental findings were corroborated by relativistic DFT calculations. The interfacial coupling is elaborated as contributions of dative bonds, hydrogen bonds and vdW interaction. The vdW is increased by a factor of 4.23 in the ZnO/g-C3N4 interface. This improves electron-hole separation and offers prospective application of the composite in photocatalysis, antibacteria and gas sensing.


Asunto(s)
Celulosa/química , Grafito/química , Nanocompuestos/química , Compuestos de Nitrógeno/química , Óxido de Zinc/química , Catálisis/efectos de la radiación , Celulosa/efectos de la radiación , Teoría Funcional de la Densidad , Grafito/efectos de la radiación , Luz , Modelos Químicos , Nanocompuestos/efectos de la radiación , Compuestos de Nitrógeno/efectos de la radiación , Electricidad Estática , Óxido de Zinc/efectos de la radiación
3.
Carbohydr Polym ; 266: 118122, 2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-34044938

RESUMEN

Hydrogels often have poor mechanical properties which limit their application in load-bearing tissues such as muscle and cartilage. In this work, a near-infrared light-triggered stretchable thermal-sensitive hydrogel with ultra-high drug loading was developed by a combination of natural polymeric nanocrystals, a network of synthetic thermo-responsive polymer, and magnetic Fe3O4 nanoparticles. The hydrogels comprise cellulose nanocrystals (CNCs) decorated with Fe3O4 nanoparticles (Fe3O4/CNCs) dispersed homogeneously in poly(N-isopropylacrylamide) (PNIPAm) networks. The composite hydrogels exhibit an extensibility of 2200%. Drug loading of vancomycin (VCM) reached a high value of 10.18 g g-1 due to the dispersion of Fe3O4/CNCs and the interactions between the CNCs and the PNIPAm network. Importantly, the hydrogels demonstrated a thermo-response triggered by NIR, with the temperature increasing from 26 to 41 °C within 60 s. The hydrogels have high biocompatibility evidenced by cell proliferation tests, illustrating that these hydrogels are promising as dressings for wound closure, and wound healing.


Asunto(s)
Celulosa/química , Portadores de Fármacos/química , Hidrogeles/química , Nanopartículas de Magnetita/química , Resinas Acrílicas/química , Resinas Acrílicas/efectos de la radiación , Resinas Acrílicas/toxicidad , Celulosa/efectos de la radiación , Celulosa/toxicidad , Portadores de Fármacos/efectos de la radiación , Portadores de Fármacos/toxicidad , Liberación de Fármacos , Células HEK293 , Humanos , Hidrogeles/efectos de la radiación , Hidrogeles/toxicidad , Rayos Infrarrojos , Nanopartículas de Magnetita/efectos de la radiación , Nanopartículas de Magnetita/toxicidad , Nanocompuestos/química , Nanocompuestos/efectos de la radiación , Nanocompuestos/toxicidad , Porosidad , Temperatura , Vancomicina/química
4.
Carbohydr Polym ; 253: 117144, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33278962

RESUMEN

The objective of this work was to investigate the influence of different gamma ray dosages (5, 10, and 10 kGy) on the structural, mechanical, surface and barrier properties of chitosan (Ch) based nanocomposite film. The results showed gamma irradiation caused an increase in the surface hydrophobicity, water vapor permeability and sensitivity of films to water and also, yellowness and opacity of films increased, simultaneously. By increasing the irradiation doses up to 10 kGy, the mechanical properties of Ch/BCNC film was significantly enhanced. As observed by FTIR spectra, no change occurred in the chemical functional groups of the films during irradiation. XRD studies confirmed that crystallinity of films was increased after irradiation. The nanocomposite film irradiated by 10 kGy had the highest thermal stability. In conclusion, gamma radiation can be considered as a safe method for sterilization of foods and modification of Ch/BCNC film properties.


Asunto(s)
Celulosa/efectos de la radiación , Quitosano/efectos de la radiación , Rayos gamma , Nanocompuestos/química , Nanocompuestos/efectos de la radiación , Nanopartículas/efectos de la radiación , Polisacáridos Bacterianos/efectos de la radiación , Plásticos Biodegradables/química , Plásticos Biodegradables/efectos de la radiación , Celulosa/química , Quitosano/química , Color , Embalaje de Alimentos/métodos , Interacciones Hidrofóbicas e Hidrofílicas/efectos de la radiación , Nanopartículas/química , Permeabilidad/efectos de la radiación , Polisacáridos Bacterianos/química , Solubilidad , Vapor , Propiedades de Superficie/efectos de la radiación , Resistencia a la Tracción , Agua/química
5.
ACS Appl Mater Interfaces ; 12(51): 57410-57420, 2020 Dec 23.
Artículo en Inglés | MEDLINE | ID: mdl-33289538

RESUMEN

The development of intelligent and multifunctional hydrogels having photothermal properties, good mechanical properties, sustained drug release abilities with low burst release, antibacterial properties, and biocompatibility is highly desirable in the biomaterial field. Herein, mesoporous polydopamine (MPDA) nanoparticles wrapped with graphene oxide (GO) were physically cross-linked in cellulose nanofibril (CNF) hydrogel to obtain a novel MPDA@GO/CNF composite hydrogel for controllable drug release. MPDA nanoparticles exhibited a high drug loading ratio (up to 35 wt %) for tetracycline hydrochloride (TH). GO was used to encapsulate MPDA nanoparticles for extending the drug release time and reinforcing the physical strength of the obtained hydrogel. The mechanical strength of the as-fabricated MPDA@GO/CNF composite hydrogel was five times greater compared to that of the pure CNF hydrogel. Drug release experiments demonstrated that burst release behavior was significantly reduced by adding MPDA@GO. The drug release time of the MPDA@GO/CNF composite hydrogel was 3 times and 7.2 times longer than that of the polydopamine/CNF hydrogel and pure CNF hydrogel, respectively. The sustained and controlled drug release behaviors of the composite hydrogel were highly dependent on the proportion of MPDA and GO. Moreover, the rate of drug release could be accelerated by near-infrared (NIR) light irradiation and pH value change. The drug release kinetics of the as-prepared composite hydrogel was well described by the Korsmeyer-Peppas model, and the drug release mechanism of TH from the composite hydrogel was anomalous transport. Importantly, this carefully designed MPDA@GO/CNF composite hydrogel showed good biocompatibility through an in vitro cytotoxicity test. In particular, the toxicity of GO was well shielded by the CNF hydrogel. Therefore, this novel MPDA@GO/CNF composite hydrogel with an encapsulation structure for controllable drug release and toxicity shielding of GO could be used as a very promising controlled drug delivery carrier, which may have potential applications for chemical and physical therapies.


Asunto(s)
Celulosa/química , Portadores de Fármacos/química , Grafito/química , Hidrogeles/química , Indoles/química , Nanofibras/química , Polímeros/química , Celulosa/efectos de la radiación , Celulosa/toxicidad , Preparaciones de Acción Retardada/química , Preparaciones de Acción Retardada/efectos de la radiación , Preparaciones de Acción Retardada/toxicidad , Portadores de Fármacos/efectos de la radiación , Portadores de Fármacos/toxicidad , Liberación de Fármacos/efectos de la radiación , Grafito/efectos de la radiación , Grafito/toxicidad , Células Endoteliales de la Vena Umbilical Humana , Humanos , Hidrogeles/efectos de la radiación , Hidrogeles/toxicidad , Indoles/efectos de la radiación , Indoles/toxicidad , Rayos Infrarrojos , Nanofibras/efectos de la radiación , Nanofibras/toxicidad , Polímeros/efectos de la radiación , Polímeros/toxicidad , Tetraciclina/química
6.
Sci Rep ; 10(1): 20401, 2020 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-33230246

RESUMEN

A precise and thorough methodology is presented for the design and fabrication of bimodal phantoms to be used in medical microwave and ultrasound applications. Dielectric and acoustic properties of human soft tissues were simultaneously mimicked. The phantoms were fabricated using polyvinyl alcohol cryogel (PVA-C) as gelling agent at a 10% concentration. Sucrose was employed to control the dielectric properties in the microwave spectrum, whereas cellulose was used as acoustic scatterer for ultrasound. For the dielectric properties at microwaves, a mathematical model was extracted to calculate the complex permittivity of the desired mimicked tissues in the frequency range from 500 MHz to 20 GHz. This model, dependent on frequency and sucrose concentration, was in good agreement with the reference Cole-Cole model. Regarding the acoustic properties, the speed of sound and attenuation coefficient were employed for validation. In both cases, the experimental data were consistent with the corresponding theoretical values for soft tissues. The characterization of these PVA-C phantoms demonstrated a significant performance for simultaneous microwave and ultrasound operation. In conclusion, PVA-C has been validated as gelling agent for the fabrication of complex multimodal phantoms that mimic soft tissues providing a unique tool to be used in a range of clinical applications.


Asunto(s)
Criogeles/química , Diagnóstico por Imagen/métodos , Modelos Anatómicos , Fantasmas de Imagen , Celulosa/química , Celulosa/efectos de la radiación , Criogeles/efectos de la radiación , Diagnóstico por Imagen/instrumentación , Humanos , Microondas , Alcohol Polivinílico/química , Alcohol Polivinílico/efectos de la radiación , Sacarosa/química , Sacarosa/efectos de la radiación , Ondas Ultrasónicas
7.
Int J Biol Macromol ; 164: 27-36, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-32673719

RESUMEN

It has been a huge challenge to obtain simultaneously excellent mechanical strength and desirable multifunctionality from the cellulose nanocrystals (CNC) based food packing materials. In this work, we demonstrated a hydrogen bonding tailoring strategy that can produce CNC/lignin films with UV blocking and antioxidant activity, while bypassing the loss of mechanical strength. Using a hyperbranched polyester, lignin was first functionalized to increase the amount of hydroxyl groups, thereby increasing the intermolecular interactions. By assembling the polyester modified lignin (H-lignin) into CNC matrix, the hydrogen bonding crosslinks between the H-lignin and CNC chains were successfully promoted, resulting in the CNC composites with the significantly improved mechanical strength, UV blocking and antioxidant activity. The phenolic structure and the hydrogen donation of H-lignin also endowed the resulting CNC composites with excellent UV blocking and antioxidant activity. The experimental results indicated that the H-lignin could bring about 34% and 63% increase in tensile strength and Young's modulus, respectively, higher than the reported ones. The CNC-based composites showed better thermal stability and improved crystallinity property. The H-lignin provides a new insight into the multifunctional exploration of CNC-based composite. This work opens a new avenue for the next generation's biodegradable food packing materials from cellulose-sourced composites.


Asunto(s)
Antioxidantes/química , Celulosa/química , Embalaje de Alimentos , Lignina/química , Materiales Manufacturados , Nanopartículas/química , Biodegradación Ambiental , Celulosa/efectos de la radiación , Módulo de Elasticidad , Enlace de Hidrógeno , Lignina/efectos de la radiación , Ensayo de Materiales , Poliésteres/química , Espectroscopía Infrarroja por Transformada de Fourier , Estrés Mecánico , Resistencia a la Tracción , Termogravimetría , Rayos Ultravioleta , Humectabilidad
8.
Nat Commun ; 11(1): 1083, 2020 02 27.
Artículo en Inglés | MEDLINE | ID: mdl-32107386

RESUMEN

Methanol is a clean liquid energy carrier of sunshine and a key platform chemical for the synthesis of olefins and aromatics. Herein, we report the conversion of biomass-derived polyols and sugars into methanol and syngas (CO+H2) via UV light irradiation under room temperature, and the bio-syngas can be further used for the synthesis of methanol. The cellulose and even raw wood sawdust could be converted into methanol or syngas after hydrogenolysis or hydrolysis pretreatment. We find Cu dispersed on titanium oxide nanorod (TNR) rich in defects is effective for the selective C-C bond cleavage to methanol. Methanol is obtained from glycerol with a co-production of H2. A syngas with CO selectivity up to 90% in the gas phase is obtained via controlling the energy band structure of Cu/TNR.


Asunto(s)
Biocombustibles , Biomasa , Nanotubos/química , Rayos Ultravioleta , Monóxido de Carbono/efectos de la radiación , Catálisis/efectos de la radiación , Celulosa/química , Celulosa/efectos de la radiación , Cobre/química , Hidrólisis , Metanol/síntesis química , Metanol/efectos de la radiación , Nitrógeno/efectos de la radiación , Polímeros/química , Polímeros/efectos de la radiación , Azúcares/química , Azúcares/efectos de la radiación , Titanio/química , Madera/química , Madera/efectos de la radiación
9.
Biomacromolecules ; 21(2): 830-838, 2020 02 10.
Artículo en Inglés | MEDLINE | ID: mdl-31940433

RESUMEN

We show ionically cross-linked, temperature-responsive reversible or irreversible hydrogels of anionic cellulose nanocrystals (CNCs) and methacrylate terpolymers by mixing them homogeneously in the initially charge-neutral state of the polymer, which was subsequently switched to be cationic by cleaving side groups by UV irradiation. The polymer is a random terpolymer poly(di(ethylene glycol) methyl ether methacrylate)-rnd-poly(oligo(ethylene glycol) methyl ether methacrylate)-rnd-poly(2-((2-nitrobenzyl)oxycarbonyl)aminoethyl methacrylate), that is, PDEGMA-rnd-POEGMA-rnd-PNBOCAEMA. The PDEGMA and POEGMA repeating units lead to a lower critical solution temperature (LCST) behavior. Initially, homogeneous aqueous mixtures are obtained with CNCs, and no gelation is observed even upon heating to 60 °C. However, upon UV irradiation, the NBOCAEMAs are transformed to cationic 2-aminoethyl methacrylate (AEMA) groups, as 2-nitrobenzaldehyde moieties are cleaved. The resulting mixtures of anionic CNC and cationic PDEGMA-rnd-POEGMA-rnd-PAEMA show gelation for sufficiently high polymer fractions upon heating to 60 °C due to the interplay of ionic interactions and LCST. For short heating times, the gelation is thermoreversible, whereas for long enough heating times, irreversible gels can be obtained, indicating importance of kinetic aspects. The ionic nature of the cross-linking is directly shown by adding NaCl, which leads to gel melting. In conclusion, the optical triggering of the polymer ionic interactions in combination with its LCST phase behavior allows a new way for ionic nanocellulose hydrogel assemblies.


Asunto(s)
Celulosa/efectos de la radiación , Hidrogeles/efectos de la radiación , Nanopartículas/efectos de la radiación , Rayos Ultravioleta , Celulosa/química , Cromatografía en Gel/métodos , Dispersión Dinámica de Luz/métodos , Hidrogeles/química , Nanopartículas/química , Temperatura
10.
J Hazard Mater ; 387: 121718, 2020 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-31771887

RESUMEN

Herein, microwave-functionalized cellulose derived from rice husk was cost-effectively prepared and employed for Pb(II), Cd(II) and Ni(II) elimination in mono- and multi-component systems. Benefiting from microwave irradiation, the functionalized process was achieved in 6.5 min and the resultant RHMW-X possessed remarkably high adsorption capacities of 295.20 mg/g for Pb(II), 151.51 mg/g for Cd(II) and 72.80 mg/g for Ni(II) within the equilibrium time of 30 min. Noticeably, the metal ions adsorption rate and capacity in binary and ternary systems were lower than that of unary systems. The coexistence of Cd(II) and Ni(II) significantly slowed down the Pb(II) adsorption in binary and ternary systems, while Pb(II) exhibited the most obvious influence on the metal ions uptake in the multi-component systems. FT-IR and XPS results revealed that both ion exchange and chelation were functioned in the metal ions uptake, while physical interaction was also involved in the adsorption process. Moreover, the RHMW-X possessed favorable recyclability with slight adsorption efficiency decline during five cycles in different systems. Particularly, the RHMW-X could effectively purify actual industrial wastewater containing Pb(II), Cd(II) and Ni(II) for meeting regulatory requirements. This work facilitates the omnidirectional improvement of adsorbents for the de-pollution of practical heavy metals wastewater.


Asunto(s)
Cadmio/aislamiento & purificación , Celulosa/química , Plomo/aislamiento & purificación , Níquel/aislamiento & purificación , Aguas Residuales/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Cadmio/química , Celulosa/efectos de la radiación , Cinética , Plomo/química , Microondas , Níquel/química , Oryza/química , Extracción en Fase Sólida/métodos , Termodinámica , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos
11.
Carbohydr Polym ; 223: 115057, 2019 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31427002

RESUMEN

It is of vital significance to fabricate high-value-added materials from agricultural wastes by environmentally friendly and cost-effective processes. In this work, we propose an approach to directly and completely convert agricultural straw into multifunctional all-biomass films by introducing an entanglement network of additional cellulose to enhance the strength of the regenerated straw. First, natural wheat straw is dissolved in the ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl). Then, a small amount of cellulose with a high degree of polymerization (DP) is introduced to obtain straw/cellulose/AmimCl solutions, which are subsequently soaked in water for biomass regeneration, washed and dried to obtain straw/cellulose films. Dynamic shear rheological test confirms that after adding high-DP cellulose, an enhanced entanglement network forms in the solutions, which is essential to the processing and mechanical properties of materials. Extensional rheological test indicates that straw/cellulose/AmimCl solutions exhibit excellent spinnability and film-forming properties based on a significant increase in the capillary break-up time. Therefore, after regeneration in water, straw-based all-biomass films with high mechanical strength are obtained. When the content of additional wood pulp (WP, DP = 1300) with respect to total solids is 25 wt%, the obtained straw/WP all-biomass film reaches a tensile strength of 62 MPa. More interestingly, because there is no intentional chemical pretreatment and compositional isolation involved in this process, almost all of the components in straw, such as cellulose, lignin, hemicellulose and inorganic compounds, are retained in the final films. Thus, the resultant films have a superhigh haze of 97% while preventing 97% UVA (320-400 nm) and almost 100% UVB (280-320 nm). In sum, we demonstrate the complete and value-added utilization of low-grade bioresources by a facile, green and economical process to fabricate high-strength, high-haze and UV-shielding all-biomass films, which have great potential in low-cost, biodegradable and environmentally friendly packaging.


Asunto(s)
Biomasa , Membranas Artificiales , Tallos de la Planta/química , Compuestos Alílicos/química , Celulosa/química , Celulosa/efectos de la radiación , Imidazoles/química , Líquidos Iónicos/química , Resistencia a la Tracción , Triticum/química , Rayos Ultravioleta
12.
Biomacromolecules ; 20(8): 3115-3125, 2019 08 12.
Artículo en Inglés | MEDLINE | ID: mdl-31274284

RESUMEN

The aim of this study was to develop composite films based on bacterial cellulose, glycerol, and poly(vinyl alcohol) with improved optical and mechanical properties and good UV-barrier property. The interaction among the compounds was analyzed using Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry. The mechanical properties (toughness, burst strength, and distance to burst), solubility, water adsorption, and light barrier properties of the composite films were evaluated. Polynomial models obtained allowed us to predict the behavior of these properties. Poly(vinyl alcohol) showed a reinforcing effect on the bacterial cellulose matrix, while glycerol showed a noticeable plasticizing behavior. The bacterial cellulose-based composites showed toughness values ranging from 0.22 to 2.60 MJ/m3. The burst strength values obtained ranged between 43.74 and 2105.52 g. The distance to burst ranged from 0.39 to 4.94 mm. The film solubility on water ranged from 9.37 to 31.65%, and the water retention ranged from 78.26 to 364.78%. Glycerol decreased the transmittance in the UV region, improving the UV-barrier properties of the films, while poly(vinyl alcohol) improved the transparency and opacity values of the samples. The transmittance in the UV regions (A, B, and C) ranged from 1 to 48.51%, increasing with the poly(vinyl alcohol) concentration.


Asunto(s)
Bacterias/química , Celulosa/química , Glicerol/química , Alcohol Polivinílico/química , Rayos Ultravioleta , Bacterias/efectos de la radiación , Celulosa/efectos de la radiación , Glicerol/efectos de la radiación , Alcohol Polivinílico/efectos de la radiación , Solubilidad , Resistencia a la Tracción , Termogravimetría
13.
Carbohydr Polym ; 216: 72-85, 2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31047084

RESUMEN

Bacterial cellulose (BC) produced by Komagataeibacter xylinus is a biomaterial with a unique three-dimensional structure. To improve the mechanical properties and reinforce the BC films, they were immersed in polyvinyl alcohol (0-4%) and chitosan (0-1%) baths. Moisture content, mechanical properties and water vapour permeability were measured to assess the effect of polyvinyl alcohol and chitosan. The morphology, optical, structural and thermal properties were evaluated by scanning electron microscopy, spectral analysis, thermogravimetry and differential scanning calorimetry. Results showed that moisture content was significantly affected by the chitosan presence. Tensile strength values in the 20.76-41.65 MPa range were similar to those of synthetic polymer films. Percentage of elongation ranged from 2.28 to 21.82% and Young's modulus ranged from 1043.88 to 2247.82 MPa. The water vapour permeability (1.47 × 10-11-3.40 × 10-11 g/m s Pa) decreased with the addition of polyvinyl alcohol. The developed films own UV light barrier properties and optimal visual appearance.


Asunto(s)
Celulosa/química , Quitosano/química , Membranas Artificiales , Alcohol Polivinílico/química , Celulosa/efectos de la radiación , Quitosano/efectos de la radiación , Módulo de Elasticidad , Gluconacetobacter xylinus/química , Permeabilidad , Alcohol Polivinílico/efectos de la radiación , Vapor , Temperatura , Resistencia a la Tracción , Rayos Ultravioleta
14.
Biomacromolecules ; 19(7): 2969-2978, 2018 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-29757619

RESUMEN

2,3-Dialdehyde cellulose (DAC) of a high degree of oxidation (92% relative to AGU units) prepared by oxidation of microcrystalline cellulose with sodium periodate (48 °C, 19 h) is soluble in hot water. Solution casting, slow air drying, hot pressing, and reinforcement by cellulose nanocrystals afforded films (∼100 µm thickness) that feature intriguing properties: they have very smooth surfaces (SEM), are highly flexible, and have good light transmittance for both the visible and near-infrared range (89-91%), high tensile strength (81-122 MPa), and modulus of elasticity (3.4-4.0 GPa) depending on hydration state and respective water content. The extraordinarily low oxygen permeation of <0.005 cm3 µm m-2 day-1 kPa-1 (50% RH) and <0.03 cm3 µm m-2 day-1 kPa-1 (80% RH) can be regarded as a particularly interesting feature of DAC films. The unusually high initial contact angle of about 67° revealed a rather low hydrophilicity compared to other oxidatively modified or unmodified cellulosic materials which is most likely the result of inter- and intramolecular hemiacetal and hemialdal formation during drying and pressing.


Asunto(s)
Celulosa/análogos & derivados , Membranas Artificiales , Celulosa/química , Celulosa/efectos de la radiación , Elasticidad , Calor , Luz , Nanopartículas/química , Oxígeno/química
15.
Int J Mol Sci ; 18(11)2017 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-29068426

RESUMEN

Bacterial cellulose (BC) is an excellent biomaterial with many medical applications. In this study, resorbable BC membranes were prepared for guided bone regeneration (GBR) using an irradiation technique for applications in the dental field. Electron beam irradiation (EI) increases biodegradation by severing the glucose bonds of BC. BC membranes irradiated at 100 kGy or 300 kGy were used to determine optimal electron beam doses. Electron beam irradiated BC membranes (EI-BCMs) were evaluated by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thermal gravimetric analysis (TGA), and using wet tensile strength measurements. In addition, in vitro cell studies were conducted in order to confirm the cytocompatibility of EI-BCMs. Cell viabilities of NIH3T3 cells on 100k and 300k EI-BCMs (100 kGy and 300 kGy irradiated BC membranes) were significantly greater than on NI-BCMs after 3 and 7 days (p < 0.05). Bone regeneration by EI-BCMs and their biodegradabilities were also evaluated using in vivo rat calvarial defect models for 4 and 8 weeks. Histometric results showed 100k EI-BCMs exhibited significantly larger new bone area (NBA; %) than 300k EI-BCMs at 8 weeks after implantation (p < 0.05). Mechanical, chemical, and biological analyses showed EI-BCMs effectively interacted with cells and promoted bone regeneration.


Asunto(s)
Materiales Biocompatibles/química , Regeneración Ósea , Celulosa/efectos de la radiación , Regeneración Tisular Dirigida/métodos , Animales , Bacterias/química , Supervivencia Celular , Electrones , Masculino , Ensayo de Materiales , Ratones , Microscopía Electrónica de Rastreo , Células 3T3 NIH , Ratas , Ratas Sprague-Dawley , Espectroscopía Infrarroja por Transformada de Fourier , Resistencia a la Tracción
16.
Int J Biol Macromol ; 98: 877-886, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28215565

RESUMEN

Herein, the highly multifunctional cotton fabric surfaces were designed with excellent coloration, UV-protection function, and antimicrobial activity. These multifunctional functions were developed by in-situ synthesis of silver nanoparticles (Ag NPs) into the cotton fabric surface using a simple green one-pot "UV-reduction" method. Cotton fabrics were pretreated with non-anionic detergent, immersed into alcoholic silver nitrate solution (concentration ranging from 100 to 500ppm), squeezed to remove excess solution and then exposed to UV-irradiation (range 320-400nm) for 1h. The influence UV-irradiation on the thermal, chemical, optical and biological properties of the cotton fabric surface was discussed in details. The UV-irradiation promotes reducing of Ag+ ions and the cotton fabrics act as seed medium for Ag NPs formation by "heterogeneous nucleation". Increasing Ag+ concentration (from 100 to 500ppm) results in Ag NPs of particle size (distribution) of 50-100nm. Interestingly, the Ag NPs exhibited different localized surface Plasmon resonance properties causing a coloration of the cotton fabrics with different color shades ranging from bright to dark brown with excellent color fastness properties. The treated cotton fabrics also show high protecting functions against UV-transmission (reduction of 65%) and Escherichia coli growth (99%). The side-effects of the UV-reduction process are further investigated.


Asunto(s)
Celulosa/química , Nanopartículas del Metal/química , Textiles , Celulosa/síntesis química , Celulosa/farmacología , Celulosa/efectos de la radiación , Fibra de Algodón , Escherichia coli/efectos de los fármacos , Tamaño de la Partícula , Plata/química , Staphylococcus aureus/efectos de los fármacos , Rayos Ultravioleta
17.
Bioresour Technol ; 232: 270-277, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28237898

RESUMEN

This study evaluated the two hydrolysis strategies, involving one thermal and one dilute acid/enzymatic hydrolysis, to produce high xylose and glucose concentrations from lignocellulose assisted with irradiation pretreatment. Prior to hydrolysis, lignocellulose was pretreated by γ-irradiation at 800KGy. The merits of irradiation pretreatment on lignocellulose were contributed to size-reduced particle distributions and low shear rate of material, which allowed high biomass loadings up to 30-40%(w/v, equals to 23-29wt.%) for the consequent hydrolysis process. Results showed that hemicellulose fraction could achieve ∼84g/L of total sugars containing ∼55g/L xylose and ∼21g/L glucose through this two steps hydrolysis. Cellulose fraction would release ∼251g/L of total sugars consisting of ∼235g/L glucose and ∼16g/L xylose in the ultimate enzymatic hydrolysate. To the best of our knowledge, it was the first report of achieving 235g/L glucose in cellulose enzymatic hydrolysate derived from lignocellulose.


Asunto(s)
Biomasa , Lignina/metabolismo , Lignina/efectos de la radiación , Oligosacáridos/metabolismo , Celulosa/metabolismo , Celulosa/efectos de la radiación , Rayos gamma , Glucosa/metabolismo , Hidrólisis/efectos de la radiación , Polisacáridos/metabolismo , Xilosa/metabolismo , Xilosa/efectos de la radiación
18.
Drug Deliv Transl Res ; 7(1): 89-99, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27815776

RESUMEN

Burn wound management is a complex process because the damage may extend as far as the dermis which has an acknowledged slow rate of regeneration. This study investigates the feasibility of using hydrogel microparticles composed of bacterial cellulose and polyacrylamide as a dressing material for coverage of partial-thickness burn wounds. The microparticulate carrier structure and surface morphology were investigated by Fourier transform infrared, X-ray diffraction, elemental analysis, and scanning electron microscopy. The cytotoxicity profile of the microparticles showed cytocompatibility with L929 cells. Dermal irritation test demonstrated that the hydrogel was non-irritant to the skin and had a significant effect on wound contraction compared to the untreated group. Moreover, histological examination of in vivo burn healing samples revealed that the hydrogel treatment enhanced epithelialization and accelerated fibroblast proliferation with wound repair and intact skin achieved by the end of the study. Both the in vitro and in vivo results proved the biocompatibility and efficacy of hydrogel microparticles as a wound dressing material.


Asunto(s)
Resinas Acrílicas , Celulosa , Portadores de Fármacos , Hidrogeles , Microondas , Resinas Acrílicas/administración & dosificación , Resinas Acrílicas/química , Resinas Acrílicas/efectos de la radiación , Resinas Acrílicas/uso terapéutico , Animales , Bacterias , Quemaduras/tratamiento farmacológico , Quemaduras/patología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Celulosa/administración & dosificación , Celulosa/química , Celulosa/efectos de la radiación , Celulosa/uso terapéutico , Portadores de Fármacos/administración & dosificación , Portadores de Fármacos/química , Portadores de Fármacos/efectos de la radiación , Portadores de Fármacos/uso terapéutico , Femenino , Hidrogeles/administración & dosificación , Hidrogeles/química , Hidrogeles/efectos de la radiación , Hidrogeles/uso terapéutico , Ratones , Ratas Sprague-Dawley , Piel/efectos de los fármacos , Piel/patología , Pruebas de Irritación de la Piel , Cicatrización de Heridas/efectos de los fármacos
19.
Bioresour Technol ; 218: 69-76, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27347800

RESUMEN

Sugarcane bagasse (SCB) was treated in three stages using ozone oxidation (O), washing in an alkaline medium (B) and ultrasonic irradiation (U). The impact of each pretreatment stage on the physical structure of the SCB was evaluated by its chemical composition, using an infrared technique (FTIR-ATR), and using thermogravimetric analysis (TGA/DTG). The pretreatment sequence O, B, U provided a significant reduction of lignin and hemicellulose, which was confirmed by changes in the absorption bands corresponding to these compounds, when observed using infrared. Thermogravimetric analysis confirmed an increased thermal stability in the treated sample due to the removal of hemicellulose and extractives during the pretreatment. This pretreatment released 391mg glucose/g from treated SCB after the enzymatic hydrolysis, corresponding to a yield of 94% of the cellulose available.


Asunto(s)
Celulasa/metabolismo , Celulosa , Ozono/farmacología , Saccharum , Sonicación , Celulasa/química , Celulosa/efectos de la radiación , Glucosa/metabolismo , Ondas de Choque de Alta Energía , Hidrólisis/efectos de los fármacos , Hidrólisis/efectos de la radiación , Lignina/análisis , Lignina/metabolismo , Oxidación-Reducción/efectos de los fármacos , Ozono/análisis , Saccharum/efectos de los fármacos , Saccharum/metabolismo , Saccharum/efectos de la radiación , Sonicación/métodos , Ultrasonido
20.
Colloids Surf B Biointerfaces ; 143: 1-6, 2016 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-27011345

RESUMEN

The goal of this project was to study the feasibility of using a DNA-immobilized nanocellulose-based immunoadsorbent for possible application in medical apheresis such as systemic lupus erythematosus (SLE) treatment. Calf thymus DNA was bound to high surface area nanocellulose membrane at varying concentrations using UV-irradiation. The DNA-immobilized samples were characterized with scanning electron microscopy, atomic force microscopy, and phosphorus elemental analysis. The anti-ds-DNA IgG binding was tested in vitro using ELISA. The produced sample showed high affinity in vitro to bind anti-ds-DNA-antibodies from mice, as much as 80% of added IgG was bound by the membrane. Furthermore, the binding efficiency was quantitatively dependent on the amount of immobilized DNA onto nanocellulose membrane. The described nanocellulose membranes are interesting immunoadsorbents for continued clinical studies.


Asunto(s)
Anticuerpos Antinucleares/aislamiento & purificación , Celulosa/química , ADN/química , Inmunoglobulina G/aislamiento & purificación , Inmunoadsorbentes/química , Animales , Celulosa/efectos de la radiación , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Humanos , Ácidos Nucleicos Inmovilizados/química , Inmunoadsorbentes/efectos de la radiación , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/patología , Lupus Eritematoso Sistémico/terapia , Ratones , Nanoestructuras/química , Plasmaféresis/métodos , Rayos Ultravioleta
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