RESUMEN

This study evaluates the use of poly(vinyl alcohol), collagen, and chitosan blends for developing a microneedle patch for the delivery of meloxicam (MEL). Results confirm successful MEL encapsulation, structural integrity, and chemical stability even after ethylene oxide sterilization. Mechanical testing indicates the patch has the required properties for effective skin penetration and drug delivery, as demonstrated by load-displacement curves showing successful penetration of pig ear surfaces at 3N of normal load. In vitro imaging confirms the microneedle patch penetrates the pig's ear cadaver skin effectively and uniformly, with histological evaluation revealing the sustained presence and gradual degradation of microneedles within the skin. Additionally, in vitro drug diffusion experiments utilizing ballistic gel suggest that microneedles commence dissolution almost immediately upon insertion into the gel, steadily releasing the drug over 24 h. Furthermore, the microneedle patch demonstrates ideal drug release capabilities, achieving nearly 100% release of meloxicam content from a single patch within 18 h. Finally, in vivo studies using pigs demonstrate the successful dissolution and transdermal drug delivery efficacy of biodegradable microneedle patches delivering meloxicam in a porcine model, with over 70% of microneedles undergoing dissolution after 3 days. While low detectable meloxicam concentrations were observed in the bloodstream, high levels were detected in the ear tissue, confirming the release and diffusion of the drug from microneedles. This work highlights the potential of microneedle patches for controlled drug release in veterinary applications.

Asunto(s)

Sistemas de Liberación de Medicamentos , Meloxicam , Agujas , Tiazinas , Meloxicam/administración & dosificación , Meloxicam/farmacocinética , Animales , Porcinos , Sistemas de Liberación de Medicamentos/instrumentación , Tiazinas/administración & dosificación , Tiazinas/farmacocinética , Tiazinas/química , Tiazoles/administración & dosificación , Tiazoles/farmacocinética , Tiazoles/química , Administración Cutánea , Piel/metabolismo , Liberación de Fármacos

RESUMEN

Understanding the environmental fate of biodegradable plastics in aquatic systems is crucial, given the alarming amount of plastic waste and microplastic particles transported through aquatic pathways. In particular, there is a need to analyze the biodegradation of commercialized biodegradable plastics upon release from wastewater treatment plants into natural aquatic systems. This study investigates the biodegradation behaviors of poly(butylene adipate terephthalate) (PBAT) and poly(vinyl alcohol) (PVA) in wastewater, freshwater, and seawater. Biodegradation of PBAT and PVA assessed through biochemical oxygen demand (BOD) experiments and microcosm tests revealed that the type of aquatic system governs the biodegradation behaviors of each plastic, with the highest biodegradation rate achieved in wastewater for both PBAT and PVA (25.6 and 32.2 % in 30 d, respectively). Plastic release pathway from wastewater into other aquatic systems simulated by sequential incubation in different microcosms suggested that PBAT exposed to wastewater and freshwater before reaching seawater was more prone to degradation than when directly exposed to seawater. On the other hand, PVA displayed comparable biodegradation rate regardless of whether it was directly exposed to seawater or had passed through other environments beforehand. Metagenome amplicon sequencing of 16S rRNA genes revealed distinct community shifts dependent on the type of plastics in changing environments along the simulated aquatic pathway. Several bacterial species putatively implicated in the biodegradation of PBAT and PVA are discussed. Our findings underscore the significant influence of pollution routes on the biodegradation of PBAT and PVA, highlighting the potential for wastewater treatment to facilitate rapid degradation compared to direct exposure to pristine aquatic environments.

RESUMEN

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.

Asunto(s)

Alginatos , Antioxidantes , Catecoles , Alcoholes Grasos , Nanofibras , Alcohol Polivinílico , Cicatrización de Heridas , Alcoholes Grasos/química , Nanofibras/química , Cicatrización de Heridas/efectos de los fármacos , Catecoles/química , Catecoles/farmacología , Catecoles/administración & dosificación , Alginatos/química , Animales , Alcohol Polivinílico/química , Antioxidantes/administración & dosificación , Antioxidantes/farmacología , Antioxidantes/química , Antiinflamatorios/administración & dosificación , Antiinflamatorios/farmacología , Antiinflamatorios/química , Humanos , Zingiber officinale/química , Sistemas de Liberación de Medicamentos/métodos , Supervivencia Celular/efectos de los fármacos , Liberación de Fármacos , Vendajes , Ratas , Polímeros/química , Masculino , Ratones

RESUMEN

A high performance poly(vinyl alcohol)/straw (PVA/SP) composite film for package was fabricated in this study by using thermal processing technology of PVA established in our research group and biaxial stretching technology. The introduction of SP disrupted the original hydrogen bonds in modified PVA by forming new hydrogen bonds with the hydroxyl groups of each component in modified system, thus promoting the stable melt casting of PVA/SP composites and also endowing the obtained PVA/SP precursor sheets with good drawability. Upon biaxial stretching, SP reinforced the crystalline structure and orientation of PVA through their hydrogen bonds with PVA, improving the mechanical strength, crystallinity and thermal stability of PVA/SP films. The film with 3.0 × 3.0 stretching ratios demonstrated the exceptional tensile strength (62.2 MPa), tear strength (119.7 kN/m), low heat shrinkage (5.2 %), and oxygen permeability coefficient (1.38 × 10-16 cm3·cm/cm2·s·Pa), which surpassed most conventional plastic films used in food packaging field. This research not only pioneered an environmentally friendly packaging solution, but also offered a novel strategy for solid-state high-value, large-scale and economical utilization of waste crop straw, greatly avoiding the adverse effects of its burning on the environment.

Asunto(s)

Embalaje de Alimentos , Alcohol Polivinílico , Resistencia a la Tracción , Alcohol Polivinílico/química , Embalaje de Alimentos/métodos , Permeabilidad

RESUMEN

Due to the increasing prevalence of articular cartilage diseases and limitations faced by current therapeutic methodologies, there is an unmet need for new materials to replace damaged cartilage. In this work, poly(vinyl alcohol) (PVA) hydrogels were reinforced with different amounts of Nomex® (known for its high mechanical toughness, flexibility, and resilience) and sterilized by gamma irradiation. Samples were studied concerning morphology, chemical structure, thermal behavior, water content, wettability, mechanical properties, and rheological and tribological behavior. Overall, it was found that the incorporation of aramid nanostructures improved the hydrogel's mechanical performance, likely due to the reinforcement's intrinsic strength and hydrogen bonding to PVA chains. Additionally, the sterilization of the materials also led to superior mechanical properties, possibly related to the increased crosslinking density through the hydrogen bonding caused by the irradiation. The water content, wettability, and tribological performance of PVA hydrogels were not compromised by either the reinforcement or the sterilization process. The best-performing composite, containing 1.5% wt. of Nomex®, did not induce cytotoxicity in human chondrocytes. Plugs of this hydrogel were inserted in porcine femoral heads and tested in an anatomical hip simulator. No significant changes were observed in the hydrogel or cartilage, demonstrating the material's potential to be used in cartilage replacement.

RESUMEN

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.

Asunto(s)

Luminiscencia , Alcohol Polivinílico , Temperatura , Alcohol Polivinílico/química , Espectrometría de Fluorescencia , Mediciones Luminiscentes , 2-Aminopurina/química , Estructura Molecular

RESUMEN

Plastic recycling, waste minimization such as process outfall valorization promotes a circular economy. Herein, food trays have been produced in the moulded pulp thermoforming process. To this end, high-density polyethylene (HDPE) outfall has been dispersed in water via Poly vinyl alcohol (PVA) addition in a Northern Bleached Softwood Kraft Pulp (NBSKP) slurry. Samples physical and mechanical properties have been evaluated. With an increasing HDPE content, parts air permeability was drastically reduced to a minimum of 2.4 ± 0.8 mL min-1. In addition, water and grease hold out properties have been increased with minimum water Cobb1800 value of 10.9 ± 5.4 gm-2 and oil Cobb1800 value of 13.18 ± 6.5 gm-2. Samples with high HDPE content demonstrated hydrophobic surface with water contact angle value above 90°. HDPE melting and binding to wood pulp fibers was monitored by SEM images. Regarding the mechanical properties, HDPE induced plastic deformation with a reduced Young modulus by 17 %. Moreover, the addition of HDPE increased wet strength by 81 %. However, the produced food tray composites with high HDPE content demonstrated low repulpability index.

RESUMEN

Silk sericin (SS)-based hydrogels show promise for wound healing due to their biocompatibility, moisture regulation, and cell proliferation properties. However, there is still a need to develop green crosslinking methods to obtain non-toxic, absorbent, and mechanically strong SS hydrogels. This study investigated the effects of three green crosslinking methods, annealing treatment (T), exposure to an absolute ethanol vapor atmosphere (V.E), and water vapor (V.A), on the physicochemical and mechanical properties of SS and poly (vinyl alcohol) (PVA) biohydrogels. X-ray diffraction and Fourier-transform infrared spectroscopy were used to determine chemical structures. Thermal properties and morphological changes were studied through thermogravimetric analysis and scanning electron microscopy, respectively. The water absorption capacity, mass loss, sericin release in phosphate-buffered saline (PBS), and compressive strength were also evaluated. The results showed that physical crosslinking methods induced different structural transitions in the biohydrogels, impacting their mechanical properties. In particular, V.A hydrogen presented the highest compressive strength at 80% deformation owing to its compact and porous structure with crystallization and bonding sites. Moreover, both the V.A and T hydrogels exhibited improved absorption capacity, stability, and slow SS release in PBS. These results demonstrate the potential of green physical crosslinking techniques for producing SS/PVA biomaterials for wound healing applications.

RESUMEN

Recently, certain challenges and accompanying drawbacks have emerged in the preparation of high-strength and tough polymer hydrogels. Insights from wood science highlight the role of the intertwined molecular structure of lignin and crystalline cellulose in contributing to wood's strength. Herein, we immersed prestretched poly(vinyl alcohol) (PVA) polymer hydrogels into a solution of nanosized lignosulfonate sodium (LS), a water-soluble anionic polyelectrolyte, to creatively reconstruct this similar structure at the molecular scale in hydrogels. The nanosized LS effectively fixed and bundled the prestretched PVA polymers while inducing the formation of dense crystalline domains within the polymer matrix. Consequently, the interwoven structure of crystalline PVA and LS conferred good strength to the composite hydrogels, exhibiting a tensile strength of up to ∼23 MPa, a fracture strain of ∼350%, Young's modulus of ∼17 MPa, toughness of ∼47 MJ/m3, and fracture energy of ∼42 kJ/m2. This hydrogel far outperformed previous hydrogels composed directly of lignin and PVA (tensile strength <1.5 MPa). Additionally, the composite hydrogels demonstrated excellent antifreezing properties (<-80 °C). Notably, the LS-assisted reconstruction technology offers opportunities for the secondary fixation of PVA hydrogel shapes and high-strength welding of hydrogel components. This work introduces an approach for the high-value utilization of LS, a green byproduct of pulp production. LS's profound biomimetic strategy will be applied in multifunctional hydrogel fields.

RESUMEN

In order to improve the functionality of natural gelatin films for active food packaging applications, a combined strategy of crosslinking via Maillard reaction and blending enhancement incorporated with poly(vinyl alcohol) (PVA) was explored. In this study, when the mass ratio of gelatin to glucose was 10:1, Maillard reaction of crosslinked gelatin films was the highest, UV absorption and browning index reached the maximum. Infrared analysis showed that PVA could form strong interfacial interactions with gelatin matrix. The presence of PVA could significantly improve the toughness, water absorption, transparency, and oxygen barrier properties of crosslinked gelatin films. When the amount of PVA reached 5 %, elongation at break and oxygen barrier properties of crosslinked gelatin films were improved by 76.7 % and 47.9 % compared with pure crosslinked gelatin film. Even when the amount of PVA reached 10 %, UV absorption (at 315 nm) of crosslinked gelatin films still exceeded 98.7 %. The addition of PVA could accelerate the dissolution and swelling of crosslinked gelatin films, promoting the migration and release of active substances (Maillard reaction products (MRPs)). The two antioxidant activities tests (DPPH and ABTS method) achieved the highest radical scavenging rates of 71.6 % and 91.2 %, respectively, with corresponding PVA addition of 5 % and 7.5 %. After continuing to add PVA, antioxidant activities began to significantly decrease, which was directly related to the decrease in the generation of MRPs. Therefore, crosslinked gelatin films reinforced with appropriate amount of PVA can be considerable potential as active films for renewable food packaging applications.

Asunto(s)

Antioxidantes , Embalaje de Alimentos , Gelatina , Reacción de Maillard , Alcohol Polivinílico , Gelatina/química , Embalaje de Alimentos/métodos , Alcohol Polivinílico/química , Antioxidantes/química , Reactivos de Enlaces Cruzados/química , Agua/química

RESUMEN

Poly(vinyl alcohol) (PVA) is a versatile synthetic polymer, used for the design of hydrogels, porous membranes and films. Its solubility in water, film- and hydrogel-forming capabilities, non-toxicity, crystallinity and excellent mechanical properties, chemical inertness and stability towards biological fluids, superior oxygen and gas barrier properties, good printability and availability (relatively low production cost) are the main aspects that make PVA suitable for a variety of applications, from biomedical and pharmaceutical uses to sensing devices, packaging materials or wastewater treatment. However, pure PVA materials present low stability in water, limited flexibility and poor biocompatibility and biodegradability, which restrict its use alone in various applications. PVA mixed with other synthetic polymers or biomolecules (polysaccharides, proteins, peptides, amino acids etc.), as well as with inorganic/organic compounds, generates a wide variety of materials in which PVA's shortcomings are considerably improved, and new functionalities are obtained. Also, PVA's chemical transformation brings new features and opens the door for new and unexpected uses. The present review is focused on recent advances in PVA-based hydrogels.

RESUMEN

Electrospinning is a widely employed manufacturing platform for tissue engineering applications because it produces structures that closely mimic the extracellular matrix. Herein, we demonstrate the potential of poly(vinyl alcohol) (PVA) electrospun nanofibers as scaffolds for tissue engineering. Nanofibers were created by needleless direct current electrospinning from PVA with two different degrees of hydrolysis (DH), namely 98% and 99% and subsequently heat treated at 180 °C for up to 16 h to render them insoluble in aqueous environments without the use of toxic cross-linking agents. Despite the small differences in the PVA chemical structure, the changes in the material properties were substantial. The higher degree of hydrolysis resulted in non-woven supports with thinner fibres (285 ± 81 nm c.f. 399 ± 153 nm) that were mechanically stronger by 62% (±11%) and almost twice as more crystalline than those from 98% hydrolysed PVA. Although prolonged heat treatment (16 h) did not influence fibre morphology, it reduced the crystallinity and tensile strength for both sets of materials. All samples demonstrated a lack or very low degree of haemolysis (<5%), and there were no notable changes in their anticoagulant activity (≤3%). Thrombus formation, on the other hand, increased by 82% (±18%) for the 98% hydrolysed samples and by 71% (±10%) for the 99% hydrolysed samples, with heat treatment up to 16 h, as a direct consequence of the preservation of the fibrous morphology. 3T3 mouse fibroblasts showed the best proliferation on scaffolds that were thermally stabilised for 4 and 8 h. Overall these scaffolds show potential as 'greener' alternatives to other electrospun tissue engineering materials, especially in cases where they may be used as delivery vectors for heat tolerant additives.

RESUMEN

PROTACs, proteolysis targeting chimeras, are bifunctional molecules inducing protein degradation through a unique proximity-based mode of action. While offering several advantages unachievable by classical drugs, PROTACs have unfavorable physicochemical properties that pose challenges in application and formulation. In this study, we show the solubility enhancement of two PROTACs, ARV-110 and SelDeg51, using Poly(vinyl alcohol). Hereby, we apply a three-fluid nozzle spray drying set-up to generate an amorphous solid dispersion with a 30% w/w drug loading with the respective PROTACs and the hydrophilic polymer. Dissolution enhancement was achieved and demonstrated for t = 0 and t = 4 weeks at 5 °C using a phosphate buffer with a pH of 6.8. A pH shift study on ARV-110-PVA is shown, covering transfer from simulated gastric fluid (SGF) at pH 2.0 to fasted-state simulated intestinal fluid (FaSSIF) at pH 6.5. Additionally, activity studies and binding assays of the pure SelDeg51 versus the spray-dried SelDeg51-PVA indicate no difference between both samples. Our results show how modern enabling formulation technologies can partially alleviate challenging physicochemical properties, such as the poor solubility of increasingly large 'small' molecules.

RESUMEN

This research aims to examine the transdermal release of water-soluble indium and zinc metallo phthalocyanine (InPc and ZnPc) compounds from the poly(vinyl alcohol) (PVA) membrane and the cytotoxicity effect of these Pcs on normal mouse fibroblasts (L929 fibroblast) and human melanoma (SK-MEL-30) cells. For this purpose, the effects of temperature, pH, drug concentration and membrane thickness on transdermal release were investigated in order to obtain the optimum transdermal release profile by preparing PVA membranes with different thicknesses and crosslinked by heat treatment. Optimum drug release was found to be 85.36% using 6 µm thick PVA membrane at 37 ± 0.5 °C, when upper cell pH 1.2 and lower cell pH 5.5, for 3 mg/mL InPc drug concentration. Under the same conditions, the drug release value for ZnPc was found to be 69.78%. In addition, in vitro studies were performed on L929 and SK-MEL-30 cells. under optimized drug (InPc and ZnPc) and membrane conditions. It was found that no significant cytotoxic effect was observed in L929 and SK-MEL-30 cells in the dark. Photodynamic tests were also carried out with InPc and ZnPc. The results show that cell viability decreases in SK-MEL-30 cells at concentrations of 10 µg/mL and above. In addition, while the InPc IC50 value was determined as 4.058 µg/mL, this value was determined as 11.574 µg/mL for ZnPc.

RESUMEN

Recent advances in the treatment of chronic wounds have focused on the development of effective strategies for cutting-edge wound dressings based on nanostructured materials, particularly biocompatible poly(vinyl alcohol) (PVA)-based electro-spun (e-spun) nanofibers. However, PVA nanofibers need to be chemically crosslinked to ensure their dimensional stability in aqueous environment and their capability to encapsulate bioactive molecules. Herein, a robust approach for the fabrication of pH-degradable e-spun PVA nanofibers crosslinked with dynamic boronic ester (BE) linkages through a coupling reaction of PVA hydroxyl groups with the boronic acid groups of a phenyl diboronic acid crosslinker is reported. This comprehensive analysis reveals the importance of the mole ratio of boronic acid to hydroxyl group for the fabrication of well-defined BE-crosslinked fibrous mats with not only dimensional stability but also the ability to retain uniform fibrous form in aqueous solutions. These nanofibers degrade in both acidic and basic conditions that mimic wound environments, leading to controlled/enhanced release of encapsulated antimicrobial drug molecules. More importantly, drug-loaded BE-crosslinked fibers show excellent antimicrobial activities against both Gram-positive and Gram-negative bacteria, suggesting that this approach of exploring dynamic BE chemistry is amenable to the development of smart wound dressings with controlled/enhanced drug release.

RESUMEN

Anti-inflammatory wound healing involves targeted drug delivery to the wound site using hydrogel materials to prolong drug effectiveness. In this work, hydrogel films were fabricated using carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) crosslinked with citric acid (CA) and glutaraldehyde (GA) at different concentrations. The crosslinker densities were optimized with various CA (2-10% w/v) and GA (1-5% v/v) concentrations. The optimized crosslink densities in the hydrogel exhibited additional functional group peaks in the FT-IR spectra at 1740 cm-1 for the C=O stretching of the ester linkage in CA and at 1060 cm-1 for the C-O-C stretching of the ether group in GA. Significantly, the internal porous structures of hydrogel composite films improved density, swelling capacities, solubility percentage reduction, and decreased water retention capacities with optimized crosslinker densities. Therefore, these hydrogel composite films were utilized as drug carriers for controlled drug release within 24 h during medical treatment. Moreover, the hydrogel films demonstrated increased triamcinolone acetonide (TAA) absorption with higher crosslinker density, resulting in delayed drug release and improved TAA efficiency in anti-inflammatory activity. As a result, the modified hydrogel showed the capability of being an alternative material with enhanced anti-inflammatory efficiency with hydrogel films.

RESUMEN

Due to their resemblance to the fibrillar structure of the extracellular matrix, electrospun nanofibrous meshes are currently used as porous and mechanically stable scaffolds for cell culture. In this study, we propose an innovative methodology for growing peptide sequences directly onto the surface of electrospun nanofibers. To achieve this, electrospun fibers were produced from a poly(acrylic acid)/poly(vinyl alcohol) blend that was thermally crosslinked and subjected to a covalent coating of branched poly(ethylenimine). The exposed amino functionalities on the fiber surface were then used for the direct solid-phase synthesis of the RGD peptide sequence. In contrast to established strategies, mainly involving the grafting of pre-synthesized peptides onto the polymer chains before electrospinning or onto the nanofibers surface, this method allows for the concurrent synthesis and anchoring of peptides to the substrate, with potential applications in combinatorial chemistry. The incorporation of this integrin-binding motive significantly enhanced the nanofibers' ability to capture human cervical carcinoma (HeLa) cells, selected as a proof of concept to assess the functionalities of the developed material.

Asunto(s)

Resinas Acrílicas , Nanofibras , Polietileneimina , Alcohol Polivinílico , Humanos , Alcohol Polivinílico/química , Resinas Acrílicas/química , Nanofibras/química , Células HeLa , Polietileneimina/química , Andamios del Tejido/química , Péptidos/química , Oligopéptidos/química , Propiedades de Superficie

RESUMEN

The electrochemical act of valve-regulated lead acid batteries can be enhanced by conductive materials like metal oxides. This work aims to examine the preparation and influence of zirconia on poly(vinyl alcohol) based gel valve-regulated lead acid battery. Characterizations like Fourier transform infrared spectroscopy, ionic conductivity, water retention study, cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge techniques were done. The optimized gel system exhibited a discharge capacity of 198.45 µAh cm-2 at the current density of 0.6 mA cm-2. The battery cell with an optimized gel matrix displayed a maximum discharge capacity of 22.5 µAh at a current of 20 µA. After 500 continuous cycles, the battery attained a discharge capacity retention of 91 %. The presence of zirconia will increase the electrochemical performance of gel valve-regulated lead acid batteries.

RESUMEN

A novel ternary blended polymer composed of cost-effective and readily available polymers was synthesized using poly (vinyl alcohol) (PVA), iota carrageenan (IC), and poly (vinyl pyrrolidone) (PVP). Sulfonated graphene oxide (SGO), prepared from recycled drinking water bottles, was utilized as a doping agent. Varying amounts (1-3 wt%) were combined into the polymer matrix. The produced hydrogel film was examined as a potential adsorbent hydrogel film for the removal of methylene blue (MB) and Gentamicin sulfate (GMS) antibiotic from an aqueous solution. The experimental results demonstrate that the presence of SGO significantly increased the adsorption efficiency of PVA/IC/PVP hydrogel film. The antimicrobial tests revealed that the PVA/IC/PVP-3% SGO hydrogel film exhibited the most potent activity against all the tested pathogenic bacteria. However, the adsorption results for MB and GMS showed that the addition of 3 wt% SGO resulted in a removal percentage that was a two fold increase in the removal percentage compared with the undoped PVA/IC/PVP hydrogel film. Furthermore, the response surface methodology (RSM) model was utilized to examine and optimize several operating parameters, including time, pH of the solution, and initial pollutant concentration. The adsorption kinetics were better characterized by the pseudo-second-order kinetics model. The composite film containing 3 wt% SGO had a maximum adsorption capacity of 606 mg g-1 for MB and 654 mg g-1 for GMS, respectively. The generated nanocomposite hydrogel film demonstrated promising potential for application in water purification systems.

Asunto(s)

Antibacterianos , Grafito , Hidrogeles , Contaminantes Químicos del Agua , Grafito/química , Adsorción , Antibacterianos/química , Antibacterianos/farmacología , Contaminantes Químicos del Agua/química , Hidrogeles/química , Alcohol Polivinílico/química , Purificación del Agua/métodos , Polímeros/química , Azul de Metileno/química , Plásticos/química

RESUMEN

Today, the construction of scaffolds promoting the differentiation of stem cells is an intelligent innovation that accelerates the differentiation toward the target tissue. The use of calcium and phosphate compounds is capable of elevating the precision and efficiency of the osteogenic differentiation of stem cells. In this research, osteoconductive electrospun poly (ɛ-caprolactone) (PCL) - poly (vinyl alcohol) (PVA) hybrid nanofibrous scaffolds containing modified cockle shell (CS) nanopowder were prepared and investigated. In this regard, the modified CS nanopowder was prepared by grinding and modifying with phosphoric acid, and it was then added to PVA nanofibers at different weight percentages. Based on the SEM images, the optimum content of the modified CS nanopowder was set at 7 wt %, since reaching the threshold of agglomeration restricted this incorporation. In the second step, the PVA-CS7 nanofibrous sample was hybridized with different PCL ratios. Concerning the hydrophilicity and mechanical strength, the sample named PCL50-PVA50-CS7 was ultimately selected as the optimized and suitable candidate scaffold for bone tissue application. The accelerated hydrolytic degradation of the sample was also studied by FTIR and SEM analyses, and the results confirmed that the mineral deposits of CS are available approximately 7 days for mesenchymal stem cells. Moreover, Alizarin red staining illustrated that the presence of CS in the PCL50-PVA50-CS7 hybrid nanofibrous scaffold may potentially lead to an increase in calcium deposits with high precipitates, authenticating the differentiation of stem cells towards osteogenic cells.