Gels最新文献

A physically and chemically cross-linked Al³⁺-CS/PAM-MBA dual-network gel with enhanced fire-suppression performance was prepared using chitosan (CS), acrylamide (AM), and N,N'-methylenebisacrylamide (MBA) as base materials. The first network was formed through the covalent cross-linking of polyacrylamide (PAM) with MBA, while the second network was established by crosslinking CS molecules with Al³⁺ ions. The optimal gel ratio was determined by evaluating its formation time and viscosity. The fire prevention and extinguishing performance of the gel was assessed through thermal stability analysis, temperature-programmed studies, infrared spectroscopy, thermal analysis, and fire-extinguishing experiments. The results indicated that the Al³⁺-CS/PAM-MBA dual-network gel exhibited excellent thermal stability and a strong self-ignition inhibition effect, effectively suppressing coal spontaneous combustion and oxidation. The gel achieved this by chemically inactivating coal molecules, disrupting the functional groups closely associated with coal-oxygen reactions and thereby hindering these reactions. Fire-extinguishing tests demonstrated that the gel restrained coal from spontaneous combustion. Upon application, the gel rapidly reduced the coal temperature, making re-ignition less likely.

Gel-based materials have found important applications in fields such as food, healthcare, cosmetics, and bioanalysis [...].

Wound healing is a complex process involving stages such as hemostasis, inflammation, proliferation, and remodeling. In this context, polymers are useful materials for wound treatment. This research used the Casting method to prepare films from 2% polyvinylpyrrolidone (PVP) gels. Subsequently, PVP films were grafted with maleic acid (MA) (PVP-g-PAM) to load naringin (NA) and silver nanoparticles (AgNPs) in order to obtain a material with pH responsiveness and antibacterial properties. The modified PVP-g-PAM films were prepared using gamma-ray irradiation through a pre-irradiation oxidative method at a dose rate of 13.7 kGy h^-1, doses ranging from 10 to 25 kGy, and reaction times from 50 to 80 min in a bath of water, all samples at 50 °C, and a fixed monomer concentration of 15% (w/v) MA in THF. The conditions that yielded the highest percentage of grafting were 20 kGy and 60 min. NA was loaded at a fixed concentration of 5%. Data release showed that the films follow the Korsmeyer-Peppas kinetic model. Synthesis of AgNPs was performed by γ-ray irradiation-reduction (10 and 30 kGy), using PVP as a stabilizer. AgNPs showed in vitro effectiveness against E. coli and S. aureus. Films were characterized by FTIR-ATR, TGA, DSC, mechanical properties, swelling index, and contact angle. Further studies must be implemented; however, the results up now suggest that PVP-g-PAM loaded with NA and AgNPs can be useful as a potential wound dressing.

Atopic dermatitis (AD) is a chronic inflammatory skin condition characterized by impaired barrier function and persistent inflammation, necessitating advanced therapeutic solutions. This study presents the development of a novel composite hydrogel scaffold composed of polyvinyl alcohol (PVA), gelatin, and Cnidium monnieri (CM) extract, designed to address the dual challenges of tissue regeneration and inflammation suppression. Fabricated via optimized freeze-thaw crosslinking and lyophilization, the scaffold exhibited a highly porous structure conducive to enhanced cell proliferation and controlled bioactive release. FT-IR analysis confirmed robust intermolecular interactions among PVA, gelatin, and CM bioactives, while SEM imaging revealed a well-developed porous network. The UPLC analysis demonstrated the sustained release of key CM compounds, such as osthole and imperatorin, which contributed to the scaffold's anti-inflammatory properties. Biological assessments using HaCaT keratinocytes under inflammatory conditions induced by TNF-α and IFN-γ revealed improved cell viability and significant suppression of IL-8 expression, a critical marker in AD-related inflammation. These findings underscore the potential of the PVA/Gel/CM composite hydrogel as an advanced therapeutic platform for inflammatory skin disorders.

The carob tree (Ceratonia siliqua L.) is a defining species of the Mediterranean region, and its fruit, the carob pod, has seen a notable increase in economic interest in recent years, primarily due to the production of locust bean gum (E410), a widely used food additive derived from the seeds. The remainder of the fruit, the carob pulp, comprises 80-90% of the fruit's weight and is typically considered a by-product, with its primary application being in animal feed. This study focused on obtaining cellulose-rich extracts from selected carob varieties cultivated in the Mediterranean region. A comprehensive physicochemical characterization of these cellulose-rich fractions was conducted, including the assessment of their antioxidant properties, specifically total phenolics and antioxidant capacity measured by the FRAP, ABTS, and CUPRAC methods. The findings reveal that carob pulp is an excellent source of carbohydrates, including soluble sugars, which constitute 33-45% of the pulp's fresh weight, depending on the variety, and cell wall polysaccharides. The cell wall polymers, with cellulose as the predominant component, account for approximately 45% of the fresh pulp weight. Notable amounts of other polysaccharides, such as pectins and hemicelluloses, were also identified. Among the studied varieties, Bugadera and Rotjal stood out as exceptional sources of cellulose-rich extracts. Carob pulp was also found to be rich in antioxidant compounds, reflected in its high antioxidant capacity. In particular, the Bugadera variety, grown under irrigated conditions, exhibited a significant concentration of phenolic compounds (24.4 mg gallic acid equivalents per gram of pulp) and high antioxidant activity across all methods used, with ABTS measurements reaching up to 391.5 mg Trolox equivalents per gram of pulp. In conclusion, these results underscore the significant potential of carob pulp as a source of valuable cellulose-rich extracts, offering applications beyond its traditional use as animal feed. By exploring these new possibilities, the economic and environmental sustainability of carob cultivation could be greatly enhanced, contributing to the broader valorization of this iconic Mediterranean fruit.

In this work, cellulose nanocrystals (CNCs) were obtained from the wood of Acacia farnesiana L. Willd (Huizache) via acid hydrolysis; then, they were used to reinforce polyacrylic acid-co-acrylamide (AAc/AAm) hydrogels synthesized in a solution process via in situ free radical photopolymerization. The nanomaterials were characterized using atomic force microscopy, dynamic light scattering (DLS), and the residual charge on the CNCs; the nanohydrogels were characterized using infrared spectroscopy, scanning electron microscopy, swelling kinetics, and Young's modulus. Soluble-grade cellulose presented 94.6% α-cellulose, 0.5% β-cellulose, and 2.7% γ-cellulose, as well as a viscosity of 8.25 cp and a degree of polymerization (DP) of 706. The CNCs averaged 180 nm in length and 20 nm in width. In the nanohydrogels, it was observed that the swelling kinetic behavior followed the Schott kinetic model, at times lower than 500 h; after that, it became linear. The results show that the hydrogel swelling capacity depended on the crosslinking agent and CNC concentration, as well as the CNC chemical and morphological properties, rather than the CNC source. The hydrogels with CNCs exhibited a decreased swelling degree compared to the hydrogels without CNCs. Young's modulus increased with CNC presence and depended on the concentration and characteristics of the CNC as a crosslinking agent.

Surimi-based products are nutritionally valuable due to their essential amino acid composition, their content of high-quality proteins with excellent digestibility, and their low fat content. However, to achieve the desired texture, a significant amount of salt (1-3%) must be added, which could compromise their health benefits. This study provides an overview of surimi production, the gelation mechanism of myosin, and the most relevant gelation enhancers that could be used in manufacturing low-salt surimi-based products. Reducing the salt content in surimi-based products presents a significant challenge for the industry, not only from technological and sensory perspectives but also in response to the growing demand of consumers for healthier food options. So, this manuscript highlights several strategies for achieving optimal quality characteristics in relation to functional properties for the surimi products industry. In addition, surimi as a raw material is often misunderstood by consumers, who may question its nutritional value and, consequently, its consumption. Therefore, it is crucial to thoroughly explain the processing of this raw material and emphasize the importance of proper myofibrillar protein gelation to develop high-value surimi-based products.

Injectable recombinant collagen hydrogels (RCHs) are crucial in biomedical applications. Culture conditions play an important role in the preparation of hydrogels. However, determining the characteristics of hydrogels under certain conditions and determining the optimal conditions swiftly still remain challenging tasks. In this study, a machine learning approach was introduced to explore the correlation between hydrogel characteristics and culture conditions and determine the optimal culture conditions. The study focused on four key factors as independent variables: initial substrate concentration, reaction temperature, pH level, and reaction time, while the dependent variable was the elastic modulus of the hydrogels. To analyze the impact of these factors on the elastic modulus, four mathematical models were employed, including multiple linear regression (ML), decision tree (DT), support vector machine (SVM), and neural network (NN). The theoretical outputs of NN were closest to the actual values. Therefore, NN proved to be the most suitable model. Subsequently, the optimal culture conditions were identified as a substrate concentration of 15% (W/V), a reaction temperature of 4 °C, a pH of 7.0, and a reaction time of 12 h. The hydrogels prepared under these specific conditions exhibited a predicted elastic modulus of 15,340 Pa, approaching that of natural elastic cartilage.

Due to the intensification of global warming and the greenhouse effect, the exploration and research of sustainable sensors have become a research direction of people. Cellulose-based hydrogels, as a new kind of green material with strong plasticity, have become a popular material for sensor development. Due to the limited mechanical properties and poor compatibility of single-cellulose-based hydrogels, researchers have modified them to not only retain the original excellent properties of cellulose hydrogels, but also increase other properties, which has broadened the field of developing cellulose hydrogel sensors. From 2017 to 2020, cellulose-based hydrogel sensors were mainly used for biosensing applications, with a focus on the detection of biomolecules. Since then, researchers have increasingly turned their attention to pressure and strain sensors, especially those that are flexible and suitable for wearable devices. This paper introduces the modification of cellulose and cellulose-based hydrogels in detail, and lists the applications of modified cellulose-based hydrogels in different functional sensor directions, which provides different ideas for the application of modified cellulose-based hydrogels in the field of sensing, and proves that they have great potential in the field of sensing.

Gel material sensors are lightweight, have fast response speeds and low driving voltages, and have recently become a popular research topic worldwide in the bionics field. A sensing unit is formed by pressing two kinds of gel materials together: a positioning layer gel based on acrylamide and lithium chloride and a sensing layer gel based on the ionic liquid BMIMBF₄. Based on a stress-strain experiment of the sensing layer gel, a constitutive relationship model of its hyperelastic mechanical properties was established, and the elastic modulus and Poisson's ratio of the sensing layer material were deduced. The capacitive response of the ion‒gel shunt capacitor to loading was observed to prove its ability to act as a pressure sensor. Although the gel thickness differs, the capacitance and load pressure exhibit a linear relationship. The capacitance was measured via cyclic voltammetry using the equivalent plate capacitor model for the positioning layer gel. The capacitance range of the gel sensor of a certain size was obtained via the cyclic voltammetry integral formula, which provided parameters for circuit design. A plate capacitor model of the sensing layer gel and an open four-impedance branch parallel model of the positioning layer gel were established. Two confirmatory experiments were designed for the models: first, the relationship between the sensing layer force and capacitance was measured, and the function curve relationship was established via a black box model; second, the theoretical and measured points of the positioning layer were compared, and the error was analyzed and corrected.