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1.
Small ; : e2407112, 2024 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-39498666

RESUMO

Plant Callus are a valuable source of pluripotent stem cells and bioactive phytochemicals. Meanwhile, the Hypericum perforatum callus extract (HPCE) is particularly rich in compounds such as hyperforin, hypericin, quercetin, and other phenolic and flavonoid derivatives. These phytochemicals exhibit strong antibacterial, antioxidant, anti-inflammatory, and anti-fibrotic properties, making them promising for wound healing. One of the most critical challenges following wound healing is the formation of fibrosis, which can compromise the complex structural integrity of skin. To address this issue, a poly(vinyl alcohol)/chitosan/alginate (PCA) wound dressing loaded with HPCE is developed. This hydrogel dressing features a porous structure with suitable mechanical properties and a high swelling capacity, potentially enhancing its effectiveness in promoting tissue regeneration and wound healing. In vitro studies have confirmed its biocompatibility, cell proliferation, and cell adhesion properties. Additionally, the dressing has demonstrated the ability to inhibit the proliferation of certain antibiotic-resistant bacteria. The in vivo studies revealed the anti-inflammatory properties, promotion of angiogenesis, facilitation of re-epithelialization, and stimulation of collagen deposition of the dressing under investigation. Moreover, the immunohistochemistry analysis of the two key markers, p16 and p53, has shown that the application of the dressing helps prevent fibrosis after wound healing.

2.
Chemistry ; 30(23): e202304137, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38253784

RESUMO

The development of a persistent luminescence system with long-lived phosphorescence and color-tunable afterglow at room temperature represents a challenge, largely due to the intensive non-radiative deactivation pathway. In this study, an ultralong-lived room temperature phosphorescence (RTP) system has been achieved using a hydrogen-bonding strategy where poly(vinyl alcohol) (PVA) matrices were doped with tryptophan (Trp) derivatives. The PVA film doped with N-α-(9-Fluorenylmethoxycarbonyl)-L-tryptophan (Fmoc-L-Trp) exhibited a long-lived phosphorescence emission of up to 3859.70 ms, and a blue afterglow for a duration greater than 34 s, under ambient conditions. The introduction of two other fluorescent dyes (i. e., Rhodamine B and Basicred14) to the PVA film facilitates adjustment to the color of the afterglow from blue to orange, and pink, by a triplet-to-singlet Förster-resonance energy transfer (TS-FRET) process. These films have been successfully applied in silk-screen printing and in multicolor afterglow light-emitting diode (LED) arrays.

3.
Macromol Rapid Commun ; : e2400418, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39475166

RESUMO

Wearable strain transducers are poised to transform the field of healthcare owing to the promise of personalized devices capable of real-time collection of human physiological health indicators. For instance, monitoring patients' progress following injury and/or surgery during physiotherapy is crucial but rarely performed outside clinics. Herein, multifunctional liquid-free ionic elastomers are designed through the volume effect and the formation of dynamic hydrogen bond networks between polyvinyl alcohol (PVA) and weak acids (phosphoric acid, phytic acid, formic acid, citric acid). An ultra-stretchable (4600% strain), highly conducting (10 mS cm-1), self-repairable (77% of initial strain), and adhesive ionic elastomer is obtained at high loadings of phytic acid (4:1 weight to PVA). Moreover, the elastomer displayed durable performances, with intact mechanical properties after a year of storage. The elastomer is used as a transducer to monitor human motions in a device comprising an ESP32-based development board. The device detected walking and/or running biomechanics and communicated motion-sensing data (i.e., amplitude, frequency) wirelessly. The reported technology can also be applied to other body parts to monitor recovery after injury and/or surgery and inform practitioners of motion biomechanics remotely and in real time to increase convalescence effectiveness, reduce clinic appointments, and prevent injuries.

4.
Ecotoxicol Environ Saf ; 285: 117123, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39353376

RESUMO

In this study, an eco-friendly and novel hydrogel based on a crosslinked polyvinyl alcohol (PVA), iota carrageenan (IC) and polyvinylpyrrolidone (PVP) scaffold, containing a large amount (10-50 wt%) of nanoscale palm fronds (NPF) as additives, for water purification was demonstrated. A life cycle assessment (LCA) findings on NPF as biomass waste incorporated into PVA_PVP_IC polymer matrix was presented, and the results highlight the necessity of focused actions to reduce environmental impact and support the palm waste utilization in a sustainable manner. The multicomponent nanocomposite hydrogels were examined as adsorbents in a system work in batches for methylene blue (MB) and paracetamol (PCT) removal. The results show that, the presence of NPF, which dispersed in the hydrogel PVA_PVP_IC scaffolds containing both covalent and non-covalent cross-linking bonds, greatly enhanced the MB and PCT adsorption efficiency. A response surface methodology (RSM) model was used to find the best operating parameters of contaminant adsorption, including time, adsorbent dose, and starting concentration of pollutants. By using this statistical model, it was found that the optimal conditions for the adsorption reaction to achieve the complete removal of MB are 66.7 h adsorption time duration, 98.5 mg L-1 starting concentration, and an adsorbent dose of 5.9 mg, while for the complete removal of PCT, it is 57.6 h adsorption time duration, 80 mg L-1 starting concentration, and an adsorbent dose of 6 mg. The reusability of the nanocomposite hydrogels were tested for 5 cycles, all showed high adsorption capacity, indicating the potential for practical application of this nanocomposite hydrogel system. This study indicates that the prepared nanocomposite hydrogel raises the standard used for treatment of wastewater and also gives a solution to protect the environment and mitigate global warming.


Assuntos
Acetaminofen , Hidrogéis , Azul de Metileno , Nanocompostos , Álcool de Polivinil , Poluentes Químicos da Água , Purificação da Água , Azul de Metileno/química , Adsorção , Álcool de Polivinil/química , Poluentes Químicos da Água/química , Nanocompostos/química , Acetaminofen/química , Purificação da Água/métodos , Hidrogéis/química , Povidona/química , Carragenina/química
5.
Luminescence ; 39(8): e4865, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39160141

RESUMO

We studied spectral properties of 1,N2-etheno-2-aminopurine after immobilization in poly (vinyl alcohol) films. The absorption spectrum of 1,N2-ε2APu consists of two peaks centered at 300 and 370 nm, and the fluorescence spectrum has maximum at about 460 nm. The fluorescence quantum efficiency is 62%. The fluorescence anisotropy reaches a value of 0.3 at longer wavelengths, while it is low at shorter wavelengths (corresponding to the second single excited state). The 1,N2-ε2APu has a relatively long fluorescence lifetime of about 16 ns and a noticeable room temperature phosphorescence with a lifetime of about 220 ms. A broad phosphorescence emission band (425-675 nm) is centered at about 530 nm and markedly overlaps with fluorescence at shorter wavelengths. Surprisingly, the phosphorescence excitation spectrum of 1,N2-ε2APu-doped poly (vinyl alcohol) film differs from the absorption and fluorescence excitation spectra. The strongest room temperature phosphorescence excitation is about 335 nm. At longer excitation wavelengths, above 450 nm, where fluorescence cannot be excited, a triplet excitation is still possible. The 1,N2-ε2APu phosphorescence anisotropy spectra confirm direct triplet state excitation. The ability to excite molecules at long wavelengths can find applications in the study of biological molecules that are unstable when excited at high energies.


Assuntos
Luminescência , Álcool de Polivinil , Temperatura , Álcool de Polivinil/química , Espectrometria de Fluorescência , Medições Luminescentes , 2-Aminopurina/química , Estrutura Molecular
6.
Knee Surg Sports Traumatol Arthrosc ; 32(5): 1187-1198, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38506124

RESUMO

PURPOSE: The aim of this study was to evaluate the role of a novel total meniscal implant in promoting meniscal regeneration and protecting articular cartilage in a rabbit model for 3 and 6 months. METHODS: Thirty-six New Zealand rabbits were selected and divided into poly(ɛ-caprolactone) (PG-Pg) scaffold group, meniscectomy group and sham group. In this study, it was investigated whether PG-Pg scaffold can prevent articular cartilage degeneration and promote tissue degeneration, and its mechanical properties at 3 and 6 months after surgery were also explored. RESULT: The degree of articular cartilage degeneration was significantly lower in the PG-Pg scaffold group than in the meniscectomy group. The number of chondrocytes increased in the PG-Pg scaffold at 3 and 6 months, while a gradual increase in the mechanical properties of the PG-Pg stent was observed from 6 months. CONCLUSION: The PG-Pg scaffold slows down the degeneration of articular cartilage, promotes tissue regeneration and improves biomechanical properties after meniscectomy. This novel meniscus scaffold holds promise for enhancing surgical strategies and delivering superior long-term results for individuals with severe meniscus tears. LEVEL OF EVIDENCE: NA.


Assuntos
Cartilagem Articular , Hidrogéis , Meniscectomia , Impressão Tridimensional , Alicerces Teciduais , Animais , Coelhos , Meniscectomia/métodos , Cartilagem Articular/cirurgia , Meniscos Tibiais/cirurgia , Poliésteres , Regeneração , Lesões do Menisco Tibial/cirurgia , Condrócitos/transplante , Fenômenos Biomecânicos , Modelos Animais de Doenças , Modelos Animais
7.
Drug Dev Ind Pharm ; 50(7): 706-719, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39115285

RESUMO

OBJECTIVE: In the current research, 6-gingerol (GA)-loaded nanofiber drug delivery system were developed, and their potential usage in wound healing was evaluated. SIGNIFICANCE: This study investigates the effectiveness of nanofibrous membranes composed of sodium alginate (SA), poly(vinyl alcohol) (PVA), and 6-gingerol (GA) as delivery systems for anti-inflammatory agents in the context of wound dressings. METHODS: GA-loaded SA/PVA nanofiber was prepared using electrospinning. In vitro characterization of this nanofiber included the examination of comprehensive in vitro characterization, anti-inflammatory and antioxidant activities, cytotoxicity, a scratch tes and in vivo skin test. RESULTS: GA was extracted from Zingiber officinale, and its successful isolation was confirmed through analyses such as H-NMR, C-NMR. Then GA was electrospuned into the SA/PVA nanofibers, and scanning electron microscopy (SEM) imaging revealed that the fiber diameters of the formulations ranged between 148 nm and 176 nm. Anti-inflammatory and antioxidant studies demonstrated that the effectiveness of GA increased with higher doses; however, this increase was accompanied by decreased cell viability. In vitro release studies revealed that GA exhibited a burst release within the first 8 h, followed by a controlled release, reaching completion within 24 h. Within the scope of in vitro release kinetics, release data are mathematically compatible with the Weibull model with high correlation. The scratch test results indicated that TB2 (%1 GA) promoted epithelialization. Furthermore, it was determined that TB2 (%1 GA) did not cause any irritation. CONCLUSIONS: As a result, TB2 shows promise as a formulation for wound dressings, offering potential benefits in the field of wound care.


Assuntos
Alginatos , Antioxidantes , Catecóis , Álcoois Graxos , Nanofibras , Álcool de Polivinil , Cicatrização , Álcoois Graxos/química , Nanofibras/química , Cicatrização/efeitos dos fármacos , Catecóis/química , Catecóis/farmacologia , Catecóis/administração & dosagem , Alginatos/química , Animais , Álcool de Polivinil/química , Antioxidantes/administração & dosagem , Antioxidantes/farmacologia , Antioxidantes/química , Anti-Inflamatórios/administração & dosagem , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/química , Humanos , Zingiber officinale/química , Sistemas de Liberação de Medicamentos/métodos , Sobrevivência Celular/efeitos dos fármacos , Liberação Controlada de Fármacos , Bandagens , Ratos , Polímeros/química , Masculino , Camundongos
8.
Int J Mol Sci ; 25(3)2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38338946

RESUMO

Poly(vinyl alcohol) is one of the most attractive polymers with a wide range of uses because of its water solubility, biocompatibility, low toxicity, good mechanical properties, and relatively low cost. This review article focuses on recent advances in poly(vinyl alcohol) electrospinning and summarizes parameters of the process (voltage, distance, flow rate, and collector), solution (molecular weight and concentration), and ambient (humidity and temperature) in order to comprehend the influence on the structural, mechanical, and chemical properties of poly(vinyl alcohol)-based electrospun matrices. The importance of poly(vinyl alcohol) electrospinning in biomedical applications is emphasized by exploring a literature review on biomedical applications including wound dressings, drug delivery, tissue engineering, and biosensors. The study also highlights a new promising area of particles formation through the electrospraying of poly(vinyl alcohol). The limitations and advantages of working with different poly(vinyl alcohol) matrices are reviewed, and some recommendations for the future are made to advance this field of study.


Assuntos
Nanofibras , Nanofibras/química , Álcool de Polivinil/química , Polímeros , Engenharia Tecidual , Solubilidade
9.
Int J Mol Sci ; 25(2)2024 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-38256100

RESUMO

In this study, a novel film of poly(vinyl alcohol) (PVA)/pullulan (PULL) with improved surface characteristics was prepared from poly(vinyl acetate) (PVAc)/PULL blend films with various mass ratios after the saponification treatment in a heterogeneous medium. According to proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared, and X-ray diffraction results, it was established that the successful fabrication of saponified PVA/PULL (100/0, 90/10, and 80/20) films could be obtained from PVAc/PULL (100/0, 90/10, and 80/20) films, respectively, after 72 h saponification at 50 °C. The degree of saponification calculated from 1H-NMR analysis results showed that fully saponified PVA was obtained from all studied films. Improved hydrophilic characteristics of the saponified films were revealed by a water contact angle test. Moreover, the saponified films showed improved mechanical behavior, and the micrographs of saponified films showed higher surface roughness than the unsaponified films. This kind of saponified film can be widely used for biomedical applications. Moreover, the reported saponified film dressing extended the lifespan of dressing as determined by its self-healing capacity and considerably advanced in vivo wound-healing development, which was attributed to its multifunctional characteristics, meaning that saponified film dressings are promising candidates for full-thickness skin wound healing.


Assuntos
Etanol , Álcool de Polivinil , Glucanos , Bandagens , Poli A , Cloreto de Polivinila
10.
Environ Monit Assess ; 196(11): 1045, 2024 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-39392488

RESUMO

In this study, in-situ modification by TEMPO oxidation was performed after nanocomposite synthesis to improve its properties toward dye molecule removal. The unoxidized and oxidized polymeric-based nanocomposite was denoted as PNC6 and PNC6O respectively. The nanocomposites were characterized using FESEM, FTIR, contact angle, XRD and BET analysis. Measurements of swelling ratio and chemical stability were also performed to provide insight into the durability of the nanocomposites. The effects of changing variables included contact duration, pH of aqueous solution, initial pollutant concentration, and temperature were observed. The kinetic study showed that the experimental data is best fitted with pseudo-second-order kinetics (R2 = 0.988 and 0.997 respectively), whereas on observing isotherm data, in both unoxidized and oxidized nanocomposite it fits well with Langmuir isotherm (R2 = 0.951 and 0.993 respectively). In addition, the effects on Gibb's free energy, Enthalpy, and Entropy were measured in terms of thermodynamic characteristics, it was established that dye molecules adsorption mechanism is endothermic and spontaneous in behaviour. To check regeneration tendency of the nanocomposite seven consecutive adsorption desorption cycles were run and about 90% and 80%, regeneration ability could be seen in an unoxidized state (PNC6) and an oxidized state (PNC6O) respectively upto 5th cycle after that the tendency get reduced. This study suggests that this novel polymeric nanocomposite can be employed as an efficient and relatively inexpensive adsorbent for dye removal from aqueous solutions.


Assuntos
Celulose , Nanocompostos , Nanopartículas , Álcool de Polivinil , Corantes de Rosanilina , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água , Nanocompostos/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Celulose/química , Álcool de Polivinil/química , Eliminação de Resíduos Líquidos/métodos , Corantes de Rosanilina/química , Nanopartículas/química , Adsorção , Óxidos N-Cíclicos/química , Corantes/química , Cinética , Oxirredução , Purificação da Água/métodos , Termodinâmica , Membranas Artificiais
11.
J Food Sci Technol ; 61(3): 481-490, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38327862

RESUMO

The development of green materials for active packaging applications is a research hotspot due to setbacks of petrochemical derived plastics. Thus, the present study aims to develop ternary blend films by doping different wt% of Tragacanth gum (TG) to Poly(vinyl alcohol)/Chitosan (PC) blend using solvent evaporation technique. Further, their various physicochemical properties were evaluated systematically. Differential scanning calorimetry studies revealed excellent compatibility and thermal stability of PC blend was significantly reinforced with 15 wt% of TG. UV-visible spectroscopy study demonstrated the excellent shielding efficacy of UV radiation by ternary blend films. Moreover, overall migration results confirmed the limited release of film constituents into food simulants and swelling ratio analysis indicated the good swelling resistance at higher wt% of TG. The ternary films exhibited tremendous chemical resistance against extreme acidic and basic environments and these green biofilms could be considered for active packaging applications.

12.
Chemphyschem ; 24(20): e202300090, 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37541308

RESUMO

A gel polymer electrolyte based on poly(vinyl alcohol) (PVA) is used in sodium-ion batteries (SIBs). The use of biodegradable and water-soluble polymer potentially reduces the negative environmental impact. The other components include sodium salt (NaPF6 ), sulfolane (TMS) as a plasticizer and talc. For the first time, natural and abundant talc has been used as an inert filler in a gel polymer electrolyte. The best results were obtained for moderate amounts of filler (1 and 3 wt%). Then, an increase in the conductivity, transference numbers, and thermal stability of the membranes was observed. Moreover, the presence of talc had a positive effect on the cyclability of the hard carbon electrode. The discharge capacity after 50 cycles of HC|1 % T_TMS|Na and HC|3 % T_TMS|Na was 243 and 225 mAh g-1 , respectively. The use of talc in gel polymer electrolytes containing sodium ions improves the safety and efficiency of SIBs.

13.
Macromol Rapid Commun ; 44(16): e2200875, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36628979

RESUMO

Tailor-made poly(vinyl alcohol)-b-poly(styrene) copolymers (PVA-b-PS) for separation membranes are synthesized by the combination of reversible-deactivation radical polymerization techniques. The special features of these di-block copolymers are the high molecular weight (>70 kDa), the high PVA content (>80 wt%), and the good film-forming property. They are soluble only in hot dimethyl sulfoxide, but by the "solvent-switch" technique, they self-assemble in aqueous media to form micelles. When the self-assembled micelles are cast on a porous substrate, thin-film membranes with higher water permeance than that of PVA homopolymer are obtained. Thus, by using these tailor-made PVA-b-PS copolymers, it is demonstrated that chemical cross-linkers and acid catalysts can no longer be needed to produce PVA membranes, since the PS nanodomains within the PVA matrix act as cross-linking points. Lastly, subsequent thermal annealing of the thin film enhances the membrane selectivity due to the improved microphase separation.


Assuntos
Micelas , Álcool de Polivinil , Álcool de Polivinil/química , Estireno , Polímeros/química , Água/química
14.
Macromol Rapid Commun ; 44(1): e2200296, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35700343

RESUMO

Adding small molecular plasticizers is the most common route to tailor the stretchability of poly(vinyl alcohol) (PVA). However, how the plasticization along with the nature of the plasticizer governs the structural homogeneity during stretching remains an open question to answer. Herein, two representative plasticizers, glycerol (GLY) and water, are chosen to endow the PVA films with ductility. It is found that large strain cavitations cause obvious stress whitening in the PVA/H2 O films; on the contrary, most of the PVA/GLY films maintain transparent undergoing tensile deformation. Through a combination of experimental inspections and molecular dynamic simulation, it is revealed that partial water molecules that behave as free water will aggregate into microdomains, which serve as mechanical defects responsible for yielding voids. Whereas, the GLY plasticizer homogeneously disperses at a molecular level and interacts with PVA chains through strong hydrogen bonds. More interestingly, it is illustrated that the dispersion and bound states of plasticizers are closely related to the mechanical character of the plasticized PVA films. These findings offer new insight into the working mechanism of plasticization on the structural stability during stretching, and guide the design of PVA/plasticizer system to obtain excellent comprehensive mechanics.


Assuntos
Álcool de Polivinil , Água , Álcool de Polivinil/química , Água/química , Plastificantes/química , Glicerol , Resistência à Tração
15.
Proc Natl Acad Sci U S A ; 117(13): 7011-7020, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32152095

RESUMO

Conservation of our cultural heritage is fundamental for conveying to future generations our culture, traditions, and ways of thinking and behaving. Cleaning art, in particular modern/contemporary paintings, with traditional tools could be risky and impractical, particularly on large collections of important works to be transferred to future generations. We report on advanced cleaning systems, based on twin-chain polymer networks made of poly(vinyl alcohol) (PVA) chains, semiinterpenetrated (semi-IPN) with PVA of lower molecular weight (L-PVA). Interpenetrating L-PVA causes a change from gels with oriented channels to sponge-like semi-IPNs with disordered interconnected pores, conferring different gel (and solvent) dynamics. These features grant residue-free, time efficient cleaning capacity and effective dirt capture, defeating risks for the artifact, making possible a safer treatment of important collections, unconceivable with conventional methods. We report as an example the conservation of Jackson Pollock's masterpieces, cleaned in a controlled way, safety and selectivity with unprecedented performance.

16.
Int J Mol Sci ; 24(2)2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36674644

RESUMO

Conventional bone cancer treatment often results in unwanted side effects, critical-sized bone defects, and inefficient cancer-cell targeting. Therefore, new approaches are necessary to better address bone cancer treatment and patient's recovery. One solution may reside in the combination of bone regeneration scaffolds with magnetic hyperthermia. By incorporating pristine superparamagnetic iron oxide nanoparticles (pSPIONs) into additively manufactured scaffolds we created magnetic structures for magnetic hyperthermia and bone regeneration. For this, hydroxyapatite (HA) particles were integrated in a polymeric matrix composed of chitosan (CS) and poly (vinyl alcohol) (PVA). Once optimized, pSPIONs were added to the CS/PVA/HA paste at three different concentrations (1.92, 3.77, and 5.54 wt.%), and subsequently additively manufactured to form a scaffold. Results indicate that scaffolds containing 3.77 and 5.54 wt.% of pSPIONs, attained temperature increases of 6.6 and 7.5 °C in magnetic hyperthermia testing, respectively. In vitro studies using human osteosarcoma Saos-2 cells indicated that pSPIONs incorporation significantly stimulated cell adhesion, proliferation and alkaline phosphatase (ALP) expression when compared to CS/PVA/HA scaffolds. Thus, these results support that CS/PVA/HA/pSPIONs scaffolds with pSPIONs concentrations above or equal to 3.77 wt.% have the potential to be used for magnetic hyperthermia and bone regeneration.


Assuntos
Quitosana , Hipertermia Induzida , Humanos , Quitosana/química , Durapatita/química , Alicerces Teciduais/química , Regeneração Óssea , Nanopartículas Magnéticas de Óxido de Ferro , Fenômenos Magnéticos , Engenharia Tecidual/métodos
17.
Molecules ; 28(8)2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-37110725

RESUMO

Nanotechnology has attracted increasing interest in various research fields for fabricating functional nanomaterials. In this study, we investigated the effect of poly(vinyl alcohol) (PVA) addition on the formation and thermoresponsive properties of poly(N-isopropyl acrylamide)-based nanogels in aqueous dispersion polymerizations. During dispersion polymerization, PVA appears to play three roles: (i) it bridges the generated polymer chains during polymerization, (ii) it stabilizes the formed polymer nanogels, and (iii) it regulates the thermoresponsive properties of the polymer nanogels. By regulating the bridging effect of PVA via changing the PVA concentration and chain length, the size of the obtained polymer gel particles was maintained in the nanometer range. Furthermore, we found that the clouding-point temperature increased when using low-molecular weight PVA. We believe that the knowledge gained in this study regarding the effect of PVA concentration and chain length on nanogel formation will aid in the future fabrication of functional polymer nanogels.

18.
Molecules ; 29(1)2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38202791

RESUMO

The interactions between poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), and lysozyme (Lys) in an aqueous environment at pHs of 2, 4, and 7.4 were discussed considering the experimental data obtained by turbidimetry, electrokinetic and rheological measurements, and FTIR analysis. It was found that the increase in PAA amount reduces the coacervation zone by shifting the critical pHcr1to higher values while the critical pHcr2 remains unchanged. The coacervation zone extended from 3.1-4.2 to 2.9-4.7 increasing the Lys concentration from 0.2% to 0.5%. The zeta potential measurements showed that the PAA-PVA-Lys mixture in water is the most stable in the pH range of 4.5-8. Zero shear viscosity exhibited deviations from additivity at both investigated pHs, and a maximum value corresponding to a maximum hydrodynamic volume was revealed at PAA weight fractions of 0.4 and 0.5 for pHs of 4 and 7.4, respectively. The binding affinity to Lys of PAA, established by molecular dynamics simulation, was slightly higher than that of PVA. The more stable complex was PAA-Lys formed in a very acidic environment; for that, a binding affinity of -7.1 kcal/mol was determined.

19.
J Sci Food Agric ; 103(7): 3592-3601, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36326723

RESUMO

BACKGROUND: The use of slow release fertilizers (SRFs) is an effective approach for reducing agriculture cost, environmental and ecological issues simultaneously. The present study provides a series of poly(vinyl alcohol) (PVA)/sodium alginate (SA) polymer membranes as eco-friendly and biodegradable coatings for SRFs. Moreover, polymer-coated urea (PCU) granules were fabricated through coating the urea granules with the resulting membranes. Our first interest was to fabricate three membranes (PS1, PS2, PS3) of different PVA/SA weight ratios (9:1, 8:2, 7:3) using glutaraldehyde as a crosslinking agent, and crosslink the PS3 membrane with a CaCl2 solution further to obtain the PC3 membrane. The chemical properties and morphologies of the membranes were characterized. Second, the nitrogen release behavior of the PCU granules was measured and calculated, respectively. RESULTS: Crosslinking with glutaraldehyde made the PS1, PS2, PS3 membranes uniform and compact, whereas crosslinking with a CaCl2 solution formed an 'egg box' structure inside the PC3 membrane. PS3 membrane with the minimum PVA/SA weight ratio had the highest hydrophily (water uptake: 106.25%, water contact angle: 55.1o ), whereas PC3 membrane had the lowest hydrophily (water uptake: 21.57%, water contact angle: 67.3o ). The biodegradation ratios of the membranes were in the range 44-60% in 90 days, indicating that they had excellent biodegradability. The measured fractional release on the day 30 of the PCU granules ranged from 89.33% to 97.07%. The calculated nitrogen release behavior agreed well with the measured values. CONCLUSION: The resulting eco-friendly and biodegradable PVA/SA membranes are alternative coatings for SRFs. © 2022 Society of Chemical Industry.


Assuntos
Polímeros , Álcool de Polivinil , Polímeros/química , Álcool de Polivinil/química , Alginatos/química , Fertilizantes/análise , Glutaral , Cloreto de Cálcio , Água/química , Ureia
20.
Angew Chem Int Ed Engl ; 62(18): e202216962, 2023 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-36637456

RESUMO

Poly(vinyl alcohol) (PVA) is a water-soluble synthetic vinyl polymer with remarkable physical properties including thermostability and viscosity. Its biodegradability, however, is low even though a large amount of PVA is released into the environment. Established physical-chemical degradation methods for PVA have several disadvantages such as high price, low efficiency, and secondary pollution. Biodegradation of PVA by microorganisms is slow and frequently involves pyrroloquinoline quinone (PQQ)-dependent enzymes, making it expensive due to the costly cofactor and hence unattractive for industrial applications. In this study, we present a modified PVA film with improved properties as well as a PQQ-independent novel enzymatic cascade for the degradation of modified and unmodified PVA. The cascade consists of four steps catalyzed by three enzymes with in situ cofactor recycling technology making this cascade suitable for industrial applications.


Assuntos
Cofator PQQ , Álcool de Polivinil , Álcool de Polivinil/química , Biodegradação Ambiental , Cofator PQQ/metabolismo
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