ENZYME AND MICROBIAL TECHNOLOGY
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2022
·
IF 3.705
Yun-Tao Zhao,Kun Zhang,Jian Zeng,Haowen Yin,Wenjing Zheng,Rui Li,Anzi Ding,Shaohong Chen,You Liu,Wenjin Wu,Zhanxin Jing
Enzyme immobilization technology has a key role in improving the stability of enzyme reaction systems and biocatalyst utilization rates. In this study, polyvinyl alcohol/sodium alginate@Fe 3 O 4 (PVA/SA@Fe 3 O 4 ) magnetic immobilized-enzyme hydrogel beads were prepared. Their structure and morphology were characterized by scanning electron microscopy, surface area and porosity analyses, Fourier transform infrared spectroscopy , X-ray photoelectron spectroscopy and a vibrating sample magnetometer. The capability of PVA/SA@Fe 3 O 4 to adsorb neutral protease was investigated with variations in composition, temperature, pH, stirring speed, enzyme concentration, and crosslinking concentration. The optimal parameters of the immobilization process were determined by response surface methodology (3% neutral protease, 4% crosslinking at 200 rpm, 45 °C and pH 7.2), under which an immobilization rate of 41.98 mg/g was obtained. The thermal stability , acid-base stability, and reusability of the immobilized enzyme were improved significantly. After seven cycles, the immobilized enzyme activity remained at 30.8% that of the initial enzyme activity . The results indicate that the immobilization of NP onto magnetic PVA/SA@Fe 3 O 4 hydrogel beads improves enzyme efficiency, giving this process potential industrial applications.
研究领域:
生物化学
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酶工程
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Food Packaging and Shelf Life
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2026
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IF 10.8
Jie Yao,Mengran Zhang,Guohua Zhao,Damao Wang
A bioactive and biodegradable packaging film was fabricated via a solvent-casting method using poly(vinyl alcohol) (PVA) reinforced with alkaline–peroxide treated brewers’ spent grain (BSG-M) and zinc oxide nanoparticles (ZnO-NPs). Alkaline–peroxide treatment was applied to BSG, which is reported to disrupt lignin–carbohydrate associations and promote microfibrillation, yielding a modified lignocellulosic filler containing residual proteins that dispersed uniformly within the PVA matrix, thereby enhancing the tensile performance and soil degradability of the composite films. The incorporation of an optimal ZnO loading (2–3 wt%) facilitated the formation of dense hydrogen-bond networks and increased the tortuosity of the diffusion path. Consequently, the composite films exhibited a UV-B blocking efficiency exceeding 96%, antibacterial inhibition rates up to ∼100% (depending on ZnO loading) against Escherichia coli and Staphylococcus aureus , and a moderate DPPH-radical scavenging activity (approximately 20%). Specifically, the PBZ-3 film (containing 3 wt% ZnO) significantly enhanced the preservation of strawberries during 8 days of storage at 4 °C. Compared with commercial polyethylene (PE) packaging, the PBZ-3 film minimized weight loss to 12.84% and provided superior vitamin C retention and improved visual quality, while maintaining the critical advantage of biodegradability. Furthermore, soil burial tests demonstrated a 54% mass loss within 30 days, confirming a favorable balance between functional performance and biodegradability. These results indicate that the PVA/BSG/ZnO ternary composite film is a promising biodegradable active packaging material with moisture-barrier, UV-shielding, antibacterial, and extract-based antioxidant functions for fresh produce.
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CARBOHYDRATE POLYMERS
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2023
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IF 11.2
Jun Ye,Luying Liu,Wu Lan,Jian Xiong
Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA) hydrogels loaded with soybean peptide (SPE) were fabricated via a freeze-thaw method. These hydrogels conquer barriers in simulated gastric fluid (SGF), and then release SPE in simulated intestinal fluid (SIF). The results of in vitro SPE release from these hydrogels showed that in SGF only a little of the SPE released, but in SIF the SPE was completely released. The released SPE had scavenging rates for DPPH and ABTS free radicals of 41.68 and 31.43 %. The pharmacokinetic model of SPE release from the hydrogels in SIF was studied. When the hydrogels are moved from SGF to SIF, the sorption of the shrinkage hydrogel network is entirely controlled by stress-induced relaxations. There are swollen and shrunken regions during SPE release. For SPE release into the SIF, SPE has to be freed from the weak bonds in the swollen regions by changes in the conformation of CMC and PVA. The release rate of SPE was found to be governed by the diffusion and swelling rate of the shrinkage hydrogel network. The Korsmeyer-Peppas equation diffusion exponents (n) for SPE release from the hydrogels are >2.063, indicating a super case II transport. These data demonstrate CMC/PVA hydrogels have potential applications in oral peptide delivery.
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Frontiers in Bioengineering and Biotechnology
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2023
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IF 5.7
Ding Jiaxin,Gao Binbin,Mei Xifan
Introduction: Photothermal responsive, antimicrobial hydrogels are very attractive and have great potential in the field of tissue engineering. The defective wound environment and metabolic abnormalities in diabetic skin would lead to bacterial infections. Therefore, multifunctional composites with antimicrobial properties are urgently needed to improve the current therapeutic outcomes of diabetic wounds. We prepared an injectable hydrogel loaded with silver nanofibers for efficient and sustained bactericidal activity.Methods: To construct this hydrogel with good antimicrobial activity, homogeneous silver nanofibers were first prepared by solvothermal method and then dispersed in PVA-lg solution. After homogeneous mixing and gelation, injectable hydrogels (Ag@H) wrapped with silver nanofibers were obtained.Results: By virtue of Ag nanofibers, Ag@H exhibited good photothermal conversion efficiency and good antibacterial activity against drug-resistant bacteria, while the in vivo antibacterial also showed excellent performance. The results of antibacterial experiments showed that Ag@H had significant bactericidal effects on MRSA and E. coli with 88.4% and 90.3% inhibition rates, respectively.Discussion: The above results indicate that Ag@H with photothermal reactivity and antibacterial activity is very promising for biomedical applications, such as wound healing and tissue engineering.
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OPTICAL MATERIALS
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2023
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IF 3.9
Lifang Wu,Jun Wang,Wenzhi Wu
In this work, photoluminescence (PL) intensity and stability of CsPbBr 3 /PbBrOH powders synthesized by one-pot method are enhanced through the encapsulation of poly (vinyl acetate) (PVA) in water. Understanding the function of PbBrOH and PVA matrix for photogenerated transition can be achieved through temperature-dependent steady-state and time-resolved PL. The enhanced PL quantum yield (65.9%) and longer lifetime indicate the strengthened structural stability and a significant reduction in nonradiative recombination of CsPbBr 3 . Negative thermal quenching can be observed and interpreted using a multilevel PL transition model. Through nanosecond time-resolved PL spectra under femtosecond laser excitation, it is revealed that the PL position shows a redshift (∼8 nm) with time delay due to the reduction of band-filling effect during the recombination of photoexcited carriers. PVA further encapsulates CsPbBr 3 /PbBrOH powders to form a flexible film, which exhibits excellent thermal and water stability due to the dual protective effects of PVA and PbBrOH. The experimental investigation demonstrates that CsPbBr 3 encapsulated by PbBrOH and PVA possesses excellent luminescent and water-resistant characteristics, making it a new choice for practical applications in LEDs and screen printing.
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2022
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IF 2.042
Siqi Wang,Xiaoyu Guo,Shuang Guan,Hai Fu,Xiufeng Wang,Peipei Guo
It is still challenging to prepare high strength hydrogels which can self-heal in both alkali and acid solutions. In this work, 6-acrylamidohexanoic acid (AACA) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (DMC) monomers were copolymerized in a mixture solution of polyvinyl alcohol (PVA) and borax to prepare high strength and pH responsive hydrogel. Compared with borax cross-linked PVA gel, this hydrogel exhibits better mechanical properties owing to multi-physical interactions like electrostatic interactions and hydrogen bonds. Due to the presence of noncovalent interactions the hydrogel exhibits different degrees of self-healing ability in acid and alkali at the same time. Furthermore, the conductivity of the hydrogel can be significantly change with slight deformation, which can be used to monitor the body movement like swallow and finger bending.
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ACS Applied Materials & Interfaces
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2022
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IF 10.383
Letian Zheng,Huanyao Hua,Ziyuan Zhang,Yutian Zhu,Lian Wang,Yongjin Li
Wearable elastic electronic devices have attracted tremendous attention due to their monitoring capabilities for human motion detection. In this work, a hydrogen bond acceptor quaternary ammonium salt, choline chloride (ChCl), has been used to fabricate deep eutectic polymer (DEP) blends with polyvinyl alcohol (PVA). The miscibility, molecular interaction, and physical properties of PVA/ChCl DEP blends were investigated systematically. It is demonstrated that the deep eutectic of PVA/ChCl can be obtained by simple solution blending, and the melting points of both PVA and ChCl are reduced respectively due to the strong hydrogen bond between PVA and ChCl. Due to the elasticity of the PVA/ChCl elastomer and the response of ChCl ions to temperature and humidity, the fabricated sensor showed stable and repeatable resistance changes upon strain, temperature, and humidity variations. We hypothesize that the DEP blend system has potential applications in functional composites and the final PVA/ChCl elastomer composites exhibited high transparent, antifreeze, and recyclable capability, which may be promising for applications in soft/flexible devices.
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CHINESE JOURNAL OF POLYMER SCIENCE
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2022
·Vol. 40
·期 11
·1402-1410
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IF 3.815
Ni Qing-Sheng,Du Miao,Shan Guo-Rong,Song Yi-Hu,Zheng Qiang
Poly(vinyl alcohol) (PVA) is usually processed and used in a form of aqueous dispersion. A large number of inter- and intramolecular hydrogen bonds make it very difficult to obtain suitable rheological behavior for processing. In this study, carbon particles with different topological shapes were added into PVA aqueous dispersion to tune the steady and dynamic rheological behavior. The results show that the zero-dimensional particles (carbon black, CB) increase monotonically the zero-shear viscosity of PVA dispersion, while the one-dimensional particles (carbon nanotubes, CNTs) make it first increase, and then decrease and rise again, like an N-shape, and the two-dimensional particles (graphene oxide, GO) can make it first decrease and then increase, exhibiting a U-shape. It is believed that the topological shape of the carbon particles brought about these discrepancies. The zero-dimensional particles mainly act as physical crosslinking points due to their small size. While at a certain content, both CNTs and GO can destroy the intermolecular hydrogen bonds between PVA chains because the PVA chains can twine around the slim CNTs and the large planar size of GO prevents the adsorbed PVA from forming hydrogen bond with other chains. The high hydroxyl value of carbon particle surface could strengthen this effect. It is expected that the viscosity of polymer dispersion can be regulated by particles with different topological shape and the surface characteristic, so as to widen the operable concentration range during preparing composite functional materials.
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CARBOHYDRATE POLYMERS
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2022
·
IF 10.723
Keyu Zhao,Changying Ren,Youwei Lu,Qijun Zhang,Qiang Wu,Siqun Wang,Chunping Dai,Wenbiao Zhang,Jingda Huang
It is still a challenge to prepare air filtration materials with high filtration efficiency and good thermal stability from renewable materials. In this study, cellulose nanofibril (CNF), poly (vinyl alcohol) (PVA), and bamboo activated charcoal (BAC) were used to build an air filtration system with double filtration by mixing and freeze-drying. The resulting CNF/PVA/BAC aerogel sheet reached a filtration efficiency of 99.69% for PM2.5 due to its double filtration from the network structure of CNF and electrostatic adsorption of BAC. The composite material also showed high thermal stability with its filtration efficiency over 95% even after exposure to 200 °C. After modification, the hydrophobic CNF/PVA/BAC filtration sheet could be reused for over 5 times by water washing whereby the filtration efficiency remained above 95%. The environmentally friendliness excellent filtration efficiency and simplistic fabrication make the aerogel sheet a potential material choice to cope with the severe air pollution today.
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Journal of Coatings Technology and Research
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2022
·Vol. 19
·期 3
·977-988
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IF 2.339
Xu Xinmeng,Zhou Zhongqun,Qin Liangrong,Yu Caili,Zhang Faai
It is difficult to produce coatings that have good mechanical and self-healing properties. In this study, polyvinyl alcohol/polyurethane/polyurea (PVA/PU/PUA) microcapsules (MCs) loaded with isophorone diisocyanate (IPDI) as core materials were first prepared by interfacial polymerization in an oil-in-water emulsion using different PVA as an emulsifier. The MCs were then uniformly dispersed in the matrix. Optical microscopy and scanning electron microscopy revealed that the size of MCs decreased as alcoholysis and polymerization degree of PVA increased. Thermogravimetric analysis showed that the MCs prepared with the high polymerization or alcoholysis degree of PVA revealed outstanding thermal stability, and the initial decomposition temperature increased by approximately 100°C compared with IPDI. Furthermore, the self-healing performance of the two-component waterborne polyurethane (2K WPU) coating system containing MCs was investigated. The 2K WPU coatings with 9 wt% PVA/PU/PUA MCs exhibited excellent self-healing, mechanical properties, and corrosion resistance, and indicated a high potential for smart coating.
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Separations
·
2022
·Vol. 9
·期 2
·26
·
IF 3.344
Xia Zhan,Rui Ge,Zhongyong Gao,Teng Gao,Luying Wang,Jiding Li
Two different types of 2D nanosheets, including hydrophobic graphene (GR) and hydrophilic graphene oxide (GO), were filled into poly (vinyl alcohol) (PVA) polymers to prepare mixed matrix membranes (MMMs) for ethanol dehydration via pervaporation. The relationship between the physical/chemical properties of graphene and pervaporation performance of MMMs was investigated by a comparison of GR/PVA and GO/PVA MMMs in microstructure and PV performance. The incorporation of GO nanosheets into PVA reduced PVA crystallinity and enhanced the membrane hydrophilicity, while the incorporation of GR into PVA led to the opposite results. The incorporation of GR/GO into PVA depressed the PVA membrane swelling degree, and the incorporation of GR showed a more obvious depression effect. GR/PVA MMMs showed a much higher separation factor than GO/PVA MMMs, while they exhibited a much lower permeation flux than GO/PVA MMMs and pristine PVA membranes. The huge difference in microstructure and performance between GO/PVA and GR/PVA MMMs was strongly associated with the oxygen-containing groups on graphene lamellae. The higher permeation flux of GO/PVA MMMs was ascribed to the facilitated transport of water molecules induced by oxygen-containing groups and exclusive channels provided by GO lamellae, while the much lower permeation flux and higher separation factor GR/PVA MMMs was resulted from the smaller GR interplanar spacing (0.33 nm) and hydrophobicity as well as barrier effect of GR lamellae on the sorption and diffusion of water molecules. It was presumed that graphene intercalated with an appropriate number of oxygen-containing groups might be a good choice to prepare PVA-based MMMs for ethanol dehydration, which would combine the advantages of GR’s high interlayer diffusion selectivity and GO’s high permeation properties. The investigation might open a door to achieve both of high permeation flux and separation factor of PVA-based MMMs by tuning the microstructure of graphene.Keywords:graphene;graphene oxide;poly (vinyl alcohol);mixed matrix membrane;ethanol dehydration;pervaporation
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Polymers
·
2023
·Vol. 15
·期 10
·2352
·
IF 5
Linxinzheng Guo,Kun Hu,Haibo Wang
Polyvinyl alcohol (PVA) is a polymeric material with good biocompatibility, excellent hydrophilicity, and a large number of hydroxyl groups. However, due to its insufficient mechanical properties and poor inhibition of bacteria, it has a lack of applications in wound dressings, stent materials, and other fields. In this study, a simple method was used to prepare composite gel materials: Ag@MXene-HACC-PVA hydrogels with a double-network structure were prepared using an acetal reaction. Due to the double cross-linked interaction, the hydrogel has good mechanical properties and is resistant to swelling. The adhesion and bacterial inhibition were enhanced due to the addition of HACC. In addition, the strain sensing properties of this conductive hydrogel were stable, and the GF (specification factor) was 1.7617 at 40–90% strain. Therefore, the dual-network hydrogel with excellent sensing properties, adhesion properties, antibacterial properties, and cytocompatibility has potential applications in biomedical materials, especially as a tissue engineering repair material.
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