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1.
Bioresour Technol ; 331: 125065, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33819908

RESUMO

The co-existence of nitrate, manganese (Mn), and antibiotics are of a wide concern. In this study, a denitrifying and manganese-oxidizing Zoogloea Q7 bacterium was immobilized using polyvinyl alcohol/sodium alginate with sponge cube (PVA/SA@sponge cube) in the reactor. The optimal operation parameters of the bioreactor were explored. Maximum nitrate, Mn(II), and tetracycline (TC) removal efficiencies of 93.00, 72.34, and 57.32% were achieved with HRT of 10 h, pH of 6.5, Mn(II) concentration of 20 mg L-1, and TC of 1 mg L-1, respectively. Fluorescence excitation-emission matrix (EEM) proved that the microorganism in the bioreactor was greatly active. Scanning electron microscope (SEM) images demonstrated that Zoogloea Q7 was commendably immobilized on the novel material. X-ray diffraction (XRD) analysis suggested that the bioprecipitate was mainly composed of MnO2 and MnCO3. Through high-throughput analysis, Zoogloea sp. Q7 was considered to be the dominant bacteria present in the bioreactor.


Assuntos
Nitratos , Álcool de Polivinil , Alginatos , Antibacterianos , Reatores Biológicos , Desnitrificação , Manganês , Compostos de Manganês , Óxidos
2.
Int J Mol Sci ; 22(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668338

RESUMO

Polymeric materials, such as polyvinyl alcohol (PVA) and ethylene-PVA copolymers (EVOH) are widely used in the food sector as packaging materials because of their excellent properties. TiO2 nanoparticles (NPs) show photocatalytic activity; when added to the aforementioned polymers, on the one hand, they are expected to provide bactericidal capacity, whereas on the other hand, they could favor nanocomposite degradation. These types of nanoparticles can be derivatized with cyclodextrin macromolecules (CDs), which can act as food preservative carriers, increasing the packaging food protective properties. In this work, films containing ß-Cyclodextrin (ßCD)-grafted TiO2 nanoparticles and PVA or EVOH were prepared. Regarding the photocatalytic activity of the nanoparticles and the possible environmental protection, accelerated aging tests for PVA, EVOH, and their composites with cyclodextrin-grafted TiO2 nanoparticle (NP) films were performed by two methods, namely, stability chamber experiments at different conditions of temperature and relative humidity and UV light irradiation at different intensities. After analyzing the systems color changes (CIELAB) and Fourier transform infrared spectroscopy (FTIR) spectra, it was observed that the film degradation became more evident when increasing the temperature (25-80 °C) and relative humidity percentage (28-80%). There was no significant influence of the presence of CDs during the degradation process. When irradiating the films with UV light, the largest color variation was observed in the nanocomposite films, as expected. Moreover, the color change was more relevant with increasing NP percentages (1-5%) due to the high photocatalytic activity of TiO2. In addition, films were characterized by FTIR spectroscopy and variation in the signal intensities was observed, suggesting the increase of the material degradation in the presence of TiO2 NPs.


Assuntos
Embalagem de Alimentos/métodos , Conservação de Alimentos , Nanopartículas/química , Titânio/química , beta-Ciclodextrinas/química , Álcool de Polivinil/química , Raios Ultravioleta
3.
Nat Commun ; 12(1): 1689, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33727548

RESUMO

Administration of drugs via the buccal route has attracted much attention in recent years. However, developing systems with satisfactory adhesion under wet conditions and adequate drug bioavailability still remains a challenge. Here, we propose a mussel-inspired mucoadhesive film. Ex vivo models show that this film can achieve strong adhesion to wet buccal tissues (up to 38.72 ± 10.94 kPa). We also demonstrate that the adhesion mechanism of this film relies on both physical association and covalent bonding between the film and mucus. Additionally, the film with incorporated polydopamine nanoparticles shows superior advantages for transport across the mucosal barrier, with improved drug bioavailability (~3.5-fold greater than observed with oral delivery) and therapeutic efficacy in oral mucositis models (~6.0-fold improvement in wound closure at day 5 compared with that observed with no treatment). We anticipate that this platform might aid the development of tissue adhesives and inspire the design of nanoparticle-based buccal delivery systems.


Assuntos
Biomimética , Bivalves/química , Sistemas de Liberação de Medicamentos , Mucosa Bucal/fisiologia , Adesividade , Administração Bucal , Animais , Linhagem Celular , Dexametasona/farmacologia , Di-Hidroxifenilalanina/química , Liberação Controlada de Fármacos , Humanos , Indóis/toxicidade , Masculino , Mucinas/química , Muco/química , Nanopartículas/química , Nanopartículas/ultraestrutura , Tamanho da Partícula , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/toxicidade , Polímeros/toxicidade , Álcool de Polivinil/química , Álcool de Polivinil/toxicidade , Ratos Sprague-Dawley , Espectrofotometria Ultravioleta , Suínos , Distribuição Tecidual
4.
Carbohydr Polym ; 259: 117753, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33674007

RESUMO

A new type of nanocellulose/poly(vinyl alcohol)/carbon dot (NPC) multifunctional hydrogel was successfully fabricated by an one-step in-situ hydrothermal method. The one-pot strategy led to the formation of a complex hydrogen bonding/dynamic boric acid ester/nitrogen-doped carbon dots network, and endowed the hydrogel with multifunctionality. The hydrogel underwent self-healing at room temperature (25 °C) and exhibited double-emission fluorescence and high mechanical strength (tensile strength of up to 2.98 MPa). An NPC hydrogel-based capacitive sensor exhibited remarkable linear capacitance responsiveness toward pressure, strain, and glucose concentration, and enabled real-time synchronous quantitative pressure/glucose sensing with multiple linear correlations, which was a key performance criteria for biomechanical sensors. The versatility and multiple advantages of the as-prepared hydrogel demonstrate the potential of biological-mechanical sensing materials using natural cellulosic biomass.


Assuntos
Técnicas Biossensoriais/métodos , Celulose/química , Hidrogéis/química , Álcool de Polivinil/química , Pontos Quânticos/química , Materiais Biocompatíveis/química , Carbono/química , Glucose/análise , Ligação de Hidrogênio , Temperatura , Resistência à Tração
5.
J Biomed Nanotechnol ; 17(2): 242-252, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33785095

RESUMO

Sericin, a silk protein, has a high potential for use as an extracellular matrix in tissue engineering applications. In this study, novel gelatin (GEL) and silk sericin (SS) were incorporated with a polyvinyl alcohol) PVA hydrogel nanocomposite (GEL-SS-PVA) scaffold that can be applied to repair cartilage. Glutaraldehyde was used as a cross-linking agent, with hydrochloric acid acting as an initiator. The microstructure characteristics of the obtained GEL-SS and GEL-SS-PVA scaffolds were also examined using FTIR and XRD spectra and their enhanced thermal stability was assessed by TGA. The blended GEL-SS and GEL-SS-PVA scaffolds were confirmed by SEM analysis to be highly porous with optimum pore sizes of 172 and 58 µm, respectively. Smaller pore sizes and improved uniformity were observed as the concentration of PVA in the GEL-SS-PVA scaffold increased. PVA decreased the tensile strength and elongation of the membranes but increased the modulus. Swelling studies showed high swellability and complete degradation in the presence of phosphate-buffered saline. Cytocompatibility of the GEL-SS-PVA scaffolds showed that these had the highest potential to promote cell proliferation as evaluated with standard microscopy using L929 fibroblasts. The prepared GEL-SS composite scaffold incorporated with the PVA hydrogel was implanted in full-thickness articular cartilage defects in rats. The repair effect of cartilage defects was observed and evaluated among the GEL-SS-PVA, GEL-SS, and control operation groups. The defects were almost completely repaired after 14 weeks in the GEL-SS-PVA group, thereby indicating that the GEL-SS-PVA composite had a favorable effect on articular cartilage defects in rat knee joint repair.


Assuntos
Cartilagem Articular , Nanocompostos , Sericinas , Animais , Gelatina , Hidrogéis , Articulação do Joelho , Álcool de Polivinil , Ratos , Seda , Engenharia Tecidual , Tecidos Suporte
6.
Carbohydr Polym ; 260: 117802, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33712150

RESUMO

Due to the significance growth in application of polymer-based nanocomposites, different methods of synthesis and different reinforces have been studied in recent years for specific purposes. In this study, using the direct blending process, polyvinyl alcohol-arabic gum-magnesium oxide nanocomposites were synthesized. These synthesized nanocomposites were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray energy diffraction (EDS) spectroscopy, X-ray surface elemental mapping (X-Ray Map), transmission electron microscopy (TEM), ultraviolet -visible (UV-vis) spectrophotometry and thermal gravimetery analysis (TGA). The results revealed that size distributions of magnesium oxide nanoparticles and synthesized nanocomposites were between 25-40 nm and 20-90 nm, respectively. Elemental map results show the magnesium oxide nanoparticles were well distributed on polymer matrix walls.


Assuntos
Goma Arábica/química , Óxido de Magnésio/química , Nanocompostos/química , Álcool de Polivinil/química , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , Difração de Raios X
7.
Carbohydr Polym ; 261: 117875, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33766362

RESUMO

Hydrogels are three-dimensional polymeric networks capable of absorbing large amounts of water or biological fluids with the properties resembling natural living tissues. Herein, polyvinyl alcohol (PVA)/N-succinyl chitosan (NSCS)/lincomycin hydrogels for wound dressing were prepared by the freezing/thawing method, then characterized by FTIR, SEM, and TGA. The compression strength, swelling behavior, water retention capacity, antibacterial activity, drug release and cytotoxicity were systematically investigated. The results showed that the introduction of NSCS remarkably enhanced the swelling capacity, leading to the maximum swelling ratio of 19.68 g/g in deionized water. The optimal compression strength of 0.75 MPa was achieved with 30 % NSCS content.Additionally, the incorporation of lincomycin brought a remarkable antibacterial activity against both Escherichia coli and Staphylococcus aureus. Specifically, 77.71 % of Staphylococcus aureus was inhibited with 75 µg/mL lincomycin, while the MTT assay demonstrated the nontoxic nature of the composite hydrogels. In summary, this PVA/NSCS/lincomycin hydrogel showed promising potential for wound dressing.


Assuntos
Curativos Hidrocoloides , Quitosana/química , Lincomicina/administração & dosagem , Álcool de Polivinil/química , Cicatrização/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Quitosana/síntese química , Quitosana/farmacologia , Liberação Controlada de Fármacos , Humanos , Lincomicina/química , Lincomicina/farmacocinética , Teste de Materiais , Testes de Sensibilidade Microbiana , Álcool de Polivinil/síntese química , Álcool de Polivinil/farmacologia
8.
AAPS PharmSciTech ; 22(3): 109, 2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33718994

RESUMO

Hydrogel wound dressings are highly effective in the therapy of wounds. Yet, most of them do not contain any active ingredient that could accelerate healing. The aim of this study was to prepare hydrophilic active dressings loaded with an anti-inflammatory compound - trans-resveratrol (RSV) of hydrophobic properties. A special attention was paid to select such a technological strategy that could both reduce the risk of irritation at the application site and ensure the homogeneity of the final hydrogel. RSV dissolved in Labrasol was combined with an aqueous sol of poly(vinyl) alcohol (PVA), containing propylene glycol (PG) as a plasticizer. This sol was transformed into a gel under six consecutive cycles of freezing (-80 °C) and thawing (RT). White, uniform and elastic membranes were successfully produced. Their critical features, namely microstructure, mechanical properties, water uptake and RSV release were studied using SEM, DSC, MRI, texture analyser and Franz-diffusion cells. The cryogels made of 8 % of PVA showed optimal tensile strength (0.22 MPa) and elasticity (0.082 MPa). The application of MRI enabled to elucidate mass transport related phenomena in this complex system at the molecular (detection of PG, confinement effects related to pore size) as well as at the macro level (swelling). The controlled release of RSV from membranes was observed for 48 h with mean dissolution time of 18 h and dissolution efficiency of 35 %. All in all, these cryogels could be considered as a promising new active wound dressings.


Assuntos
Criogéis/síntese química , Álcool de Polivinil/síntese química , Resveratrol/síntese química , Cicatrização , Antioxidantes/administração & dosagem , Antioxidantes/síntese química , Antioxidantes/farmacocinética , Curativos Hidrocoloides , Criogéis/administração & dosagem , Criogéis/farmacocinética , Álcool de Polivinil/administração & dosagem , Álcool de Polivinil/farmacocinética , Resveratrol/administração & dosagem , Resveratrol/farmacocinética , Resistência à Tração/efeitos dos fármacos , Resistência à Tração/fisiologia , Cicatrização/efeitos dos fármacos , Cicatrização/fisiologia
9.
AAPS PharmSciTech ; 22(3): 92, 2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33683477

RESUMO

Venetoclax (VX) used in the treatment of chronic lymphocytic leukemia possesses low oral bioavailability (5.4%) and undergoes first-pass metabolism. Development of a formulation to overcome its bioavailability problem can be done by using nanocrystals which has many scientific applications. Nanocrystals of VX were formulated using amalgamation of precipitation and high-pressure homogenization method, in which polyvinyl alcohol (PVA) was selected as stabilizer. Process parameters like concentration of stabilizer, homogenization pressure, number of homogenization cycle, and concentration of lyoprotectant were optimized to obtain the desired particle size for the preparation of nanocrystal formulation. HPLC methods were developed and validated in-house for determination of in vitro dissolution data and in vivo bioavailability data. Physicochemical characterization was done to determine the particle size (zeta sizer), crystalline nature (DSC and XRPD), solubility (shaker bath), and dissolution (USP type 2 apparatus). Lyophilized VX nanocrystals of size less than 350 nm showed substantial increase in saturation solubility (~20 folds) and dissolution in comparison with free VX. In vitro release study revealed that 100% dissolution was achieved in 120 min as compared to VX free base which is having less than 43.5% dissolution in 120 min. Formulations of VX remain stable for 6 months under accelerated stability conditions. In vivo pharmacokinetic data in male Sprague-Dawley rats showed (~2.02 folds) significant increase in oral bioavailability of VX formulation as compared to free drug because of rapid dissolution and absorption which makes the nanocrystal formulation a better approach for oral administration of poorly soluble drugs.


Assuntos
Antineoplásicos/administração & dosagem , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Sulfonamidas/administração & dosagem , Administração Oral , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Disponibilidade Biológica , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacocinética , Cromatografia Líquida de Alta Pressão , Liofilização , Masculino , Nanopartículas , Tamanho da Partícula , Álcool de Polivinil , Ratos , Ratos Sprague-Dawley , Solubilidade , Sulfonamidas/química , Sulfonamidas/farmacocinética
10.
Sci Total Environ ; 774: 144826, 2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-33610986

RESUMO

Low temperatures, or a sudden decrease in operating temperature, can seriously inhibit anammox activity, it is, therefore, important to maintain anammox activities at a low temperature. In this study, the use of gel beads to enhance the resistance of anammox biomass to a low temperature was investigated. The performance of three reactors: R1 without gel beads; R2 with polyvinyl alcohol/chitosan (PVA/CS); R3 with PVA/CS/Fe, was studied and compared in a temperature transition from 35 to 8 °C. When the operating temperature was ≥25 °C, there was little difference in nitrogen removal among the three reactors. Decreasing the temperature to < 25 °C created obvious difference between R1 and R2/R3. R1 had a nitrogen removal efficiency (NRE) of 33.1 ± 25.3% at 10 °C, significantly lower than that of R2 (90.5 ± 2.5%) or R3 (87.7 ± 11.1%). Unclassified Candidatus Brocadiaceae was the dominant genus at 10 °C, with an abundance of 44.4, 56.5 and 58.7% in R1, R2 and R3, respectively. These differences were attributed to the use of gel beads, which promoted the granulation of both the non-immobilized sludge and the immobilized biomass, resulting in higher anammox activities in R2/R3. The non-immobilized sludge of R1 was dominated by small particles (<300 µm) at 10 °C, while in R2 and R3 large particles (1000-2000 µm) were the main components. Furthermore, the immobilized biomass on gel beads exhibited much higher anammox activity and maintained a relatively high level of nitrate reductase and nitrite reductase in response to the temperature decrease. The Fe2+/Fe3+ in the PVA/CS/Fe gel beads further promoted microbial aggregation and led to an improved performance in R3 compared to R2. The results of this study demonstrate an effective approach to increase anammox resistance at low operating temperatures.


Assuntos
Reatores Biológicos , Álcool de Polivinil , Anaerobiose , Nitrogênio , Oxirredução , Esgotos , Temperatura
11.
J Chromatogr A ; 1641: 462006, 2021 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-33640807

RESUMO

Bio-based and low-cost hybrid polyvinyl alcohol (PVA) and gelatin (Gel) hydrophilic macromolecular complex coated microspheres were prepared based on one-pot process, characterized, and applied as novel sorbent materials for the purification of trace aminoglycosides from complex matrices. PVA acts as a "rigid" component in the hybrid complex to enhance its mechanical properties, while Gel's "flexible" role is to improve the swelling properties of the hybrid complex in water. It is shown that hybrid PVA/Gel-functionalized sorbents are more efficient than the respective PVA or Gel sorbents since the presence of Gel increases the material selectivity for aminoglycosides, which is due to the specific interactions occurring between the targets and amino acid residues in the hybrid materials. Under the optimum conditions, material preparation and pretreatment processes were entirely carried out in single water system without toxic organic solvent. The detection limit (LOD) of spectinomycin, kanamycin, streptomycin and dihydrostreptomycin in honey were 0.811, 0.303, 0.168, 0.045 µg⋅kg-1 respectively. Linearity was obtained in the range of 20 to 2000 ug⋅kg-1, relative recovery yield up to 84.1-111.7% were obtained and matrix effect of all four aminoglycosides was within 100.8-107.6%. Intra-day and inter-day precision under four spiking levels (5, 200, 500 and 1000 ug⋅kg-1) were less than 10.9% (n=6) and 13.6% (n=3) respectively. In addition, the sorbents exhibited excellent reusability even after six recycles. This work demonstrates the potential of bio-based and low-cost hybrid polymer extraction platforms as promising bonded phase alternatives, in which eco-friendly and natural-based polymers can be used to improve the material selectivity and are conducive to the realization of "green chemistry".


Assuntos
Aminoglicosídeos/isolamento & purificação , Álcool de Polivinil/química , Dióxido de Silício/química , Adsorção , Calibragem , Géis , Mel/análise , Limite de Detecção , Microesferas , Padrões de Referência , Reprodutibilidade dos Testes , Extração em Fase Sólida
12.
Bioresour Technol ; 326: 124778, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33545627

RESUMO

The newly developed carrier granular sludge (CGS) with polyvinyl alcohol/chitosan (PVA/CS) and PVA/CS/Fe gel beads assistance showed higher intensity and anammox activity than the natural granular sludge (NGS). Through comprehensive investigation, it was found: (1) the gel beads provided a stable framework of cells entangle with extracellular polymeric substances (EPS) to enhance the sludge intensity. In this framework, ß-polysaccharides are distributed at the edge of CGS as a protection layer, α-polysaccharides and proteins are spread in the whole cross-section as backbones, and Fe2+/Fe3+ in CGS-PVA/CS/Fe act as bridges to link with the negatively charged groups on bacterial surfaces and proteins. (2) The porous gel beads satisfied a relatively unimpeded mass transfer. Thus, the sludge activity, microbe's metabolism, membrane transportation and environmental adaption in CGS were apparently improved. The results improved the understanding about the advantages of the CGS and indicated their possible application in full-scale anammox processes.


Assuntos
Quitosana , Esgotos , Matriz Extracelular de Substâncias Poliméricas , Ferro , Álcool de Polivinil
13.
ACS Appl Mater Interfaces ; 13(6): 7539-7545, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33535743

RESUMO

Recent research on conductive hydrogels has revealed their potential for building advanced soft bioelectronic devices. Their mechanical flexibility, water content, and porosity approach those of biological tissues, providing a compliant interface between the human body and electronic hardware. Conductive hydrogels could be utilized in many soft tools such as neural electrodes, tactile interfaces, soft actuators, and other electroactive devices. However, most of the available conductive hydrogels exhibit weak mechanical properties, which hinders their application in durable biointegrated systems. Here, we report aramid nanofiber-based hydrogels providing a combination of high elasticity, strength, and electrical conductivity. Highly branched aramid nanofibers (ANFs) provide a robust three-dimensional (3D) framework resembling those in load-bearing soft tissues. When interlaced with poly(vinyl alcohol) (PVA) and cross-linked with both noncovalent and covalent interactions, the nanofiber composites exhibit a high water content of ∼76.4 wt %, strength of ∼7.5 MPa, ductility of ∼407%, and shape recovery of ∼99.5% under cyclic tensile stress of 0.3 MPa. Mobile ions impart a conductivity of ∼2 S/m to the hydrogels, enabling large-strain sensors with stable operation. In addition, the embedded silver nanoparticles afford broad-spectrum antimicrobial activities, which is favorable for medical devices. The versatility of aramid nanofiber-based composites suggests their further possibilities for functionalization and scalable fabrication toward sophisticated bioelectronic systems.


Assuntos
Reagentes para Ligações Cruzadas/química , Hidrogéis/química , Nanofibras/química , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica , Humanos , Tamanho da Partícula , Álcool de Polivinil/química , Propriedades de Superfície
14.
Food Chem ; 348: 129021, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-33545643

RESUMO

Lemon essential oils (LEO), as natural bacteriostatic agents, show significant loss in the preparation processes of food packaging materials, therefore, an effective encapsulation of LEO is urgent for realizing the protection. In this study, LEO was absorbed by thermally stable and porous vermiculite (VML) to form LEO/VML complex, which is further coupled with konjac glucomannan-grafted-poly (acrylic acid)/polyvinyl alcohol (KGM-g-PAA/PVA) composite. KGM-g-PAA/PVA bacteriostatic water-absorbing pad was prepared via electrospinning technique, which can minimize the loss of LEO. The VML (1 g) can significantly reduce LEO loss and achieve sustained control LEO release from the pad, which follows the predominant mechanism of Fick diffusion law. The sustained control LEO release from the pad can effectively inhibit the growth of E. coli during storage, thus prolonging shelf life of chilled pork for 3 day. This study suggests that KGM-g-PAA/PVA pad may have a great potential in the field of intelligent packaging.


Assuntos
Silicatos de Alumínio/química , Antibacterianos/química , Antibacterianos/farmacologia , Conservação de Alimentos/métodos , Mananas/química , Óleos Vegetais/química , Álcool de Polivinil/química , Animais , Preparações de Ação Retardada , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos , Armazenamento de Alimentos , Água/química
15.
Int J Biol Macromol ; 172: 330-340, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33453256

RESUMO

Novel nanocomposite hydrogels were successfully prepared by blending and crosslinking sodium alginate (SA), poly(vinyl alcohol) (PVA) and cellulose nanofibers (CNFs) in the presence of a fertilizer formulation containing nitrogen (N), phosphorus (P) and potassium (K). The hydrogels had a macroporous flexible core and a microporous semi- interpenetrating polymer network (IPN) shell. The crystalline nature of the NPK chemicals was retained in the hydrogel nanocomposite network. Furthermore, the SA/CNF/PVA-based hydrogels showed a higher water-retention capacity in both deionized water and mixed soil. The swelling behavior in various physiological pH, salt and alkali solutions exhibited good sensitivity. The NPK release from SA/CNF/NPK and SA/CNF/PVA/NPK hydrogels was controlled by Fickian diffusion in both water and soil based on the Korsmeyer-Peppas release kinetics model (n < 0.5). Therefore, the prepared hydrogels have the potential for applications in drought-prone and/or fertilizer-loss regions for future development of precision agriculture and horticulture.


Assuntos
Alginatos/química , Preparações de Ação Retardada/química , Nanofibras/química , Nitrogênio/química , Fósforo/química , Álcool de Polivinil/química , Potássio/química , Agricultura/métodos , Cristalização , Liberação Controlada de Fármacos , Fertilizantes/análise , Humanos , Concentração de Íons de Hidrogênio , Cinética , Nanofibras/ultraestrutura , Porosidade , Água/química
16.
Carbohydr Polym ; 255: 117443, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436232

RESUMO

Owning to the viscoelastic properties, good biocompatibility and high strain sensitivity, choline chloride-based deep eutectic solvent (DES) hydrogels have been considered to be promising wearable strain sensors for human motion. However, traditional hydrogels are far away from the wearable strain sensor applications caused by their unsatisfied conductivity and weak mechanical properties. Herein, the strategy for functional ionic inorganic/organic interpenetrating (IPN) hydrogels preparation by cyclic freezing/thawing method was successfully developed. Polyvinyl alcohol (PVA) was proposed to dissolve in choline chlorede-based DES as hydrogel matrix for the first time. Encouragingly, the obtained DES/PVA/CNCs/g-C3N4 hydrogel (choline chloride with glucose) exhibits excellent mechanical properties, included excellent tensile strength (≈ 2.55 MPa), high elongation (≈1200 %) and satisfactory tensile modulus (≈3.65 MPa). Interestingly, the thermal diffusivity (the maximum value was 0.675 W/mK) and conductivity (the maximum value was 0.18 mm2/s) of the DES-hydrogels were successfully achieved through adding graphitic-like nitride nanosheet (g-C3N4) and sustainable cellulose nanocrystalline (CNCs). These enhancements were attributed to the synergistic interactions of powerful hydrogen bonding among DES, CNCs, g-C3N4 and PVA chains. More importantly, the as-prepared hydrogels have the potential as a human motion sensor to accurately in-situ detect human activities on the fingers, wrists, elbows and knee joints. Those hydrogel-type strain sensors with flexibility, excellent mechanical properties, self-recovery, good heat transfer, and electrical conductivity have broad application prospects in the fields of intelligent robot, bionic prostheses, and human care areas.


Assuntos
Materiais Biocompatíveis/química , Técnicas Biossensoriais , Hidrogéis/química , Movimento/fisiologia , Nanoestruturas/química , Dispositivos Eletrônicos Vestíveis , Fenômenos Biomecânicos , Celulose/química , Colina/química , Cristalização , Elasticidade , Cotovelo/fisiologia , Condutividade Elétrica , Dedos/fisiologia , Glucose/química , Humanos , Ligação de Hidrogênio , Articulação do Joelho/fisiologia , Nanoestruturas/ultraestrutura , Álcool de Polivinil/química , Resistência à Tração , Viscosidade , Punho/fisiologia
17.
J Agric Food Chem ; 69(3): 1068-1078, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33448221

RESUMO

Nowadays, films with antibacterial activity and applied for freshness monitoring by colorimetric response have been drawing growing attention in food packaging. However, the development of versatile antibacterial and colorimetric agents is still highly desirable. Herein, WO3 nanorods are incorporated in a polyvinyl alcohol (PVA) matrix to develop a novel composite film with photothermal antibacterial activity and freshness monitoring faculty. The interaction between WO3 nanorods and PVA is due to hydrogen bonds. Compared with the PVA film, the presence of WO3 nanorods can significantly enhance the mechanical and barrier properties; typically, the target film (WO3/PVA)4 shows an increase in tensile strength by 52.7% and Young's modulus by 400.0% and a decrease in oxygen permeability by 72.4% and water vapor permeability by 66.9%. The films demonstrate a WO3 content-dependent antibacterial activity. Under irradiation of near-infrared light (NIR808), the synergistic effect of physical damage, oxidative stress, and temperature increase markedly improves the antibacterial activity of (WO3/PVA)4, showing an antibacterial efficiency of ∼90% against Escherichia coli or beyond 90% against Staphylococcus aureus. The incorporated WO3 nanorods demonstrate lower cytotoxicity toward the model cells of human colon cancer cell line HT-29. The (WO3/PVA)4 film exhibits colorimetric response to H2S and can also be used for pork freshness monitoring as an indicator.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Embalagem de Alimentos/instrumentação , Óxidos/química , Álcool de Polivinil/química , Tungstênio/química , Antibacterianos/síntese química , Antibacterianos/efeitos da radiação , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Ligação de Hidrogênio , Raios Infravermelhos , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Resistência à Tração
18.
Int J Biol Macromol ; 172: 66-73, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33434549

RESUMO

The high mechanical strength and self-healing properties of hydrogels are the focus of tissue engineering and biomedical research. Furthermore, the incompatibility between hydrogel toughness and self-healing has not been resolved. It is noteworthy that the double network (DN) hydrogels show great promise as a viable method for producing self-healing hydrogels with the above properties. The Xylan/PVA/Borax DN hydrogel was prepared by the one-pot method, shows various excellent performances, including strong strength (ca. 81 kPa), high toughness (ca.1652.42 kJ/m3), good self-recovery (ca. 79% recovery), and excellent self-healing properties (self-healing efficiency reached to 85.8% for 30 s). This study proposes a strategy to design high strength, high toughness, large extensibility, and self-healing properties hydrogels based on xylan.


Assuntos
Boratos/química , Hidrogéis/química , Álcool de Polivinil/química , Xilanos/química , Resistência à Tração/efeitos dos fármacos , Engenharia Tecidual/métodos , Água/química
19.
Int J Biol Macromol ; 172: 114-123, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33444658

RESUMO

The aim of this work was to study an improved solvent evaporation method to prepare poly (lactic acid) (PLA) microspheres via foam-transfer. Since the foaming process and its transfer were critical to the improved method, they have been studied. Additionally, the delivery capability of foams was studied as a function of the oil/water ratio, the stirring rate, the concentration of polyvinyl alcohol (PVA) and ethanol (EtOH) in the aqueous phase (ωPVA, ωEtOH). It was found that foaming varied during the preparation process and it influenced the properties of PLA microspheres. When the oil/water ratio (w/w) ≥ 3:10, stirring rate ≥ 600 r/min, ωPVA ≥ 1 wt%, and ωEtOH = 0 wt%, solvent evaporation was able to produce enough foams for foam-transfer, which helped to deliver more than 89 wt% PLA microspheres to the receiving vessel. However, ωPVA ≤ 0.3 wt% and ωEtOH = 20 wt% were unfavorable for maintaining the spherical shape of PLA microspheres and caused the aggregation. The methodology was further used to prepare azoxystrobin-loaded PLA microspheres successfully with a high encapsulation efficiency of 86.54%. This work is meaningful since it enables an efficient and continuous route to prepare functional biodegradable polymer microspheres.


Assuntos
Poliésteres/química , Solventes/química , Etanol/química , Microesferas , Polímeros/química , Álcool de Polivinil/química , Pirimidinas/química , Estrobilurinas/química , Água/química
20.
Molecules ; 26(3)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499342

RESUMO

Cartilage has a limited inherent healing capacity after injury, due to a lack of direct blood supply and low cell density. Tissue engineering in conjunction with biomaterials holds promise for generating cartilage substitutes that withstand stress in joints. A major challenge of tissue substitution is creating a functional framework to support cartilage tissue formation. Polyvinyl alcohol (PVA) was crosslinked with glutaraldehyde (GA), by varying the mole ratios of GA/PVA in the presence of different amounts of plant-derived carboxymethyl cellulose (CMC). Porous scaffolds were created by the freeze-drying technique. The goal of this study was to investigate how CMC incorporation and crosslinking density might affect scaffold pore formation, swelling behaviors, mechanical properties, and potential use for engineered cartilage. The peak at 1599 cm-1 of the C=O group in ATR-FTIR indicates the incorporation of CMC into the scaffold. The glass transition temperature (Tg) and Young's modulus were lower in the PVA/CMC scaffold, as compared to the PVA control scaffold. The addition of CMC modulates the pore architecture and increases the swelling ratio of scaffolds. The toxicity of the scaffolds and cell attachment were tested. The results suggest that PVA/CMC scaffolding material can be tailored in terms of its physical and swelling properties to potentially support cartilage formation.


Assuntos
Carboximetilcelulose Sódica/química , Cartilagem Articular/citologia , Cartilagem Articular/fisiologia , Álcool de Polivinil/química , Tecidos Suporte/química , Materiais Biocompatíveis/química , Varredura Diferencial de Calorimetria , Cartilagem Articular/lesões , Adesão Celular/fisiologia , Sobrevivência Celular , Células Cultivadas , Condrócitos/citologia , Condrócitos/fisiologia , Reagentes para Ligações Cruzadas , Módulo de Elasticidade , Humanos , Hidrogéis , Teste de Materiais , Microscopia Eletrônica de Varredura , Porosidade , Regeneração/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Engenharia Tecidual/métodos , Cicatrização/fisiologia
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