Journal Description
Gels
Gels
is an international, peer-reviewed, open access journal on physical and chemical gels published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q1 (Polymer Science)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 11.1 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Testimonials: See what our editors and authors say about the Gels.
Impact Factor:
4.6 (2022);
5-Year Impact Factor:
5.2 (2022)
Latest Articles
Effect of Polymer and Crosslinker Concentration on Static and Dynamic Gelation Behavior of Phenolic Resin Hydrogel
Gels 2024, 10(5), 325; https://doi.org/10.3390/gels10050325 - 9 May 2024
Abstract
The application results of profile control and water plugging technology are highly related to the gelation time and strength of phenolic resin hydrogel. In this work, a hydrogel solution was prepared by fully mixing the prepared polymer solution with a crosslinker. The static
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The application results of profile control and water plugging technology are highly related to the gelation time and strength of phenolic resin hydrogel. In this work, a hydrogel solution was prepared by fully mixing the prepared polymer solution with a crosslinker. The static gelation process of PFR hydrogel in ampoule bottles and porous media was analyzed by changes in the viscosity and residual resistance coefficient. Then, the dynamic gelation of the PFR hydrogel in porous media was tested using a circulating flow device, and the changes in viscosity and injection pressure were analyzed during the dynamic gelation process. Finally, the effects of the polymer concentration and crosslinker concentration on dynamic gelation were analyzed. The initial gelation time and final gelation time in porous media were 1–1.5 times and 1.5–2 times those in ampoule bottles under static conditions, respectively. The initial dynamic gelation time in porous media was 2–2.5 times and 1.5–2 times the initial static gelation times in ampoule bottles and porous media, respectively. The final dynamic gelation time was four times and two times the initial static gelation times in ampoule bottles and porous media, respectively. The production after dynamic gelation in porous media comprised hydrogel aggregates and water fluid, leading to a high injection pressure and low viscosity of the produced liquid. As the concentration of polymer and crosslinker increased, the dynamic gelation time was shortened and the gel strength was increased. In the dynamic gelation process in porous media, the phenol resin hydrogel could migrate deeply, but it was limited by the concentrations of the polymer and crosslinker. The results of subsequent water flooding showed that the polymer hydrogel had a good plugging ability after dynamic gelation. The deep reservoir could only be blocked off in the subsequent water flooding process when the migration of hydrogel happened in the dynamic gelation process.
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(This article belongs to the Special Issue Gels for Oil and Gas Industry Applications (2nd Edition))
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Terahertz Spectroscopic Insight into the Hydrogelation of Copper Ion-Coordinated Poly(vinyl alcohol)
by
Wenjing Wang, Yadi Wang, Junhong Lü and Xueling Li
Gels 2024, 10(5), 324; https://doi.org/10.3390/gels10050324 - 9 May 2024
Abstract
Metal-coordinated hydrogels are becoming increasingly popular in the biomedical field due to their unique properties. However, the mechanism behind gel forming involving metal ions is not yet fully understood. In this work, terahertz spectroscopy was used to investigate the role of interfacial water
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Metal-coordinated hydrogels are becoming increasingly popular in the biomedical field due to their unique properties. However, the mechanism behind gel forming involving metal ions is not yet fully understood. In this work, terahertz spectroscopy was used to investigate the role of interfacial water in the gelation process of copper ion-coordinated poly(vinyl alcohol) hydrogels. The results showed that the binding of copper ions could alter the interfacial hydration dynamics of the poly(vinyl alcohol) polymers. Combined with the results of differential scanning calorimetry (DSC), we propose a possible hydration layer-mediated mechanism for the formation of cooper ion-coordinated hydrogel during the freeze–thaw cycle. These results highlight the value of terahertz spectroscopy as a sensor for studying the hydration process in hydrogels and provide an important clue for understanding the mechanism of hydrogelation in ion-coordinated hydrogels.
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(This article belongs to the Special Issue Properties and Structure of Hydrogel-Related Materials)
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Open AccessEditorial
Editorial for the Special Issue “Hydrogels for 3D Printing”
by
Enrique Aguilar and Helena Herrada-Manchón
Gels 2024, 10(5), 323; https://doi.org/10.3390/gels10050323 - 9 May 2024
Abstract
Hydrogels, which are three-dimensional networks of hydrophilic polymers capable of absorbing and retaining large amounts of water, have emerged as versatile materials with vast potential in various fields [...]
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(This article belongs to the Special Issue Hydrogels for 3D Printing)
Open AccessArticle
Growth of Romaine Lettuce in Eggshell Powder Mixed Alginate Hydrogel in an Aeroponic System for Water Conservation and Vitamin C Biofortification
by
Fariha Afnan, Md Nayeem Hasan Kashem, Rutwik Joshi, Catherine Simpson and Wei Li
Gels 2024, 10(5), 322; https://doi.org/10.3390/gels10050322 - 9 May 2024
Abstract
Vitamin C is crucial for physical well-being, and its deficiency can lead to severe health consequences. Biofortification has been used to address this deficiency by enhancing vitamin C in plants. Additionally, soilless agriculture has been used to conserve and optimize water use in
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Vitamin C is crucial for physical well-being, and its deficiency can lead to severe health consequences. Biofortification has been used to address this deficiency by enhancing vitamin C in plants. Additionally, soilless agriculture has been used to conserve and optimize water use in comparison to conventional agriculture. While hydrogels have been shown to improve water conservation and are used for biofortification in crops, their application has only been explored in soil-based and hydroponic farming. The aeroponics system is a plant-growing method that has shown potential for increasing yields and biomass while conserving water and nutrients. In this paper, we have developed an aeroponic-compatible medium to grow romaine lettuce (Lactuca sativa L.) with eggshell powder (ESP) mixed with calcium-alginate hydrogel as a substrate and nutrient source aiming to conserve water and incorporate vitamin C through biofortification. Herein, lower water spray time and higher intervals, with varied gel types and ESP concentrations, resulted in healthy lettuce growth. Plants treated with 0.5% ascorbic acid-absorbed ESP-mixed alginate hydrogel for biofortification showed higher levels of vitamin C compared to the traditional method. This study suggests using an alginate hydrogel–ESP-based substrate in aeroponics to reduce water usage and enhance plant biofortification of vitamin C.
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(This article belongs to the Special Issue Application of Gel Technology in Food Industry and Environmental Engineering)
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Open AccessArticle
Structural Analyses of Polysaccharides Extracted from Cyanobacterial Extracellular Gels and Oriented Liquid Crystalline Microfiber Processing by Poly(vinyl alcohol)-Assisted Electrospinning
by
Chizu Mitani, Maiko Okajima, Tomomi Ohashira, Mohammad Asif Ali, Toshiaki Taniike and Tatsuo Kaneko
Gels 2024, 10(5), 321; https://doi.org/10.3390/gels10050321 - 7 May 2024
Abstract
Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural
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Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural analyses of the sacran rods. A heterogeneous acid-hydrolysis method using a protonated cation-exchange resin was adopted to examine the short-time exposition of concentrated acid to sacran rods. From the supernatant, the oligomeric fraction that was soluble in water and methanol was isolated. The oligomeric fraction had a main sugar ratio of α-Glc:β-Glc:α-Xyl:β-Xyl:α-Rha of 2:5:1.5:1.5:4 (Glc:Xyl:Rha = 7 (=4 + 3):3:4), and it was speculated that the sacran structure includes rhamnoglucan and xyloglucan (4:3), which are generally rigid enough to exhibit LC. To make oriented microfibers of LC sacran, solubility testing was performed on sacran to find good new solvents of polyhydroxy alcohols such as ethylene glycol, 1,2-propanediol, and glycerol. The oriented film was prepared from a sacran aqueous solution where calcium compound particles deposited on the film are different from polyhydroxy alcohol solutions. Although sacran could not form microfibers by itself, polymer composite microfibers of sacran with poly(vinyl alcohol) were prepared by electrospinning. Cross-polarizing microscopy revealed the molecular orientation of the microfibers.
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(This article belongs to the Special Issue Stimuli-Responsive Composite Gels)
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Open AccessArticle
Innovative Acrylic Resin-Hydrogel Double-Layer Coating: Achieving Dual-Anchoring, Enhanced Adhesion, and Superior Anti-Biofouling Properties for Marine Applications
by
Boning Jiang, Yuhan Zhang, Ruiyang Wang, Ting Wang and En Zeng
Gels 2024, 10(5), 320; https://doi.org/10.3390/gels10050320 - 7 May 2024
Abstract
Traditional anti-corrosion and anti-fouling coatings struggle against the harsh marine environment. Our study tackled this by introducing a novel dual-layer hydrogel (A-H DL) coating system. This system combined a Cu2O–SiO2–acrylic resin primer for anchoring and controlled copper ion release
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Traditional anti-corrosion and anti-fouling coatings struggle against the harsh marine environment. Our study tackled this by introducing a novel dual-layer hydrogel (A-H DL) coating system. This system combined a Cu2O–SiO2–acrylic resin primer for anchoring and controlled copper ion release with a dissipative double-network double-anchored hydrogel (DNDAH) boasting superior mechanical strength and anti-biofouling performance. An acrylamide monomer was copolymerized and cross-linked with a coupling agent to form the first irreversible network and first anchoring, providing the DNDAH coating with mechanical strength and structural stability. Alginate gel microspheres (AGMs) grafted with the same coupling agent formed the second reversible network and second anchoring, while coordinating with Cu2+ released from the primer to form a system buffering Cu2+ release, enabling long-term antibacterial protection and self-healing capabilities. FTIR, SEM, TEM, and elemental analyses confirmed the composition, morphology, and copper distribution within the A-H DL coating. A marine simulation experiment demonstrated exceptional stability and anti-fouling efficacy. This unique combination of features makes A-H DL a promising solution for diverse marine applications, from ship hulls to aquaculture equipment.
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(This article belongs to the Special Issue Functionalized Gels for Environmental Applications (2nd Edition))
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Design and Synthesis of P(AAm-co-NaAMPS)-Alginate-Xanthan Hydrogels and the Study of Their Mechanical and Rheological Properties in Artificial Vascular Graft Applications
by
Zhutong Li, Joshua Giarto, Jue Zhang, Jinsu Gim, Edward Chen, Eduardo Enriquez, Lauren Jafuta, Esha Mahalingam and Lih-Sheng Turng
Gels 2024, 10(5), 319; https://doi.org/10.3390/gels10050319 - 7 May 2024
Abstract
Cardiovascular diseases (CVDs) are the number one cause of mortality among non-communicable diseases worldwide. Expanded polytetrafluoroethylene (ePTFE) is a widely used material for making artificial vascular grafts to treat CVDs; however, its application in small-diameter vascular grafts is limited by the issues of
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Cardiovascular diseases (CVDs) are the number one cause of mortality among non-communicable diseases worldwide. Expanded polytetrafluoroethylene (ePTFE) is a widely used material for making artificial vascular grafts to treat CVDs; however, its application in small-diameter vascular grafts is limited by the issues of thrombosis formation and intimal hyperplasia. This paper presents a novel approach that integrates a hydrogel layer on the lumen of ePTFE vascular grafts through mechanical interlocking to efficiently facilitate endothelialization and alleviate thrombosis and restenosis problems. This study investigated how various gel synthesis variables, including N,N’-Methylenebisacrylamide (MBAA), sodium alginate, and calcium sulfate (CaSO4), influence the mechanical and rheological properties of P(AAm-co-NaAMPS)-alginate-xanthan hydrogels intended for vascular graft applications. The findings obtained can provide valuable guidance for crafting hydrogels suitable for artificial vascular graft fabrication. The increased sodium alginate content leads to increased equilibrium swelling ratios, greater viscosity in hydrogel precursor solutions, and reduced transparency. Adding more CaSO4 decreases the swelling ratio of a hydrogel system, which offsets the increased swelling ratio caused by alginate. Increased MBAA in the hydrogel system enhances both the shear modulus and Young’s modulus while reducing the transparency of the hydrogel system and the pore size of freeze-dried samples. Overall, Hydrogel (6A12M) with 2.58 mg/mL CaSO4 was the optimal candidate for ePTFE–hydrogel vascular graft applications due to its smallest pore size, highest shear storage modulus and Young’s modulus, smallest swelling ratio, and a desirable precursor solution viscosity that facilitates fabrication.
Full article
(This article belongs to the Special Issue Hydrogels: Synthesis, Characterization and Applications (2nd Edition))
Open AccessArticle
Gelatin-Based Hydrogel Functionalized with Dopamine and Layered Double Hydroxide for Wound Healing
by
Weijie Zhang, Bing Zhang, Yihu Wang, Xiaofeng Cao, Jianing Wang, Weipeng Lu and Yanchuan Guo
Gels 2024, 10(5), 318; https://doi.org/10.3390/gels10050318 - 7 May 2024
Abstract
Hydrogels with adhesion properties and a wetted structure are promising alternatives to traditional wound dressing materials. The insufficiency of gelatin hydrogels in terms of their adhesive and mechanical strength limits their application in wound dressings. This work presents the design and preparation of
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Hydrogels with adhesion properties and a wetted structure are promising alternatives to traditional wound dressing materials. The insufficiency of gelatin hydrogels in terms of their adhesive and mechanical strength limits their application in wound dressings. This work presents the design and preparation of a gelatin-based hydrogel functionalized with dopamine (DA) and layered double hydroxide (LDH). The combination of DA and LDH improves the hydrogel’s adhesion properties in terms of interfacial adhesion and inner cohesion. Hydrogels with 8% DA and 4% LDH attained the highest adhesion strength of 266.5 kPa, which increased to 295.5 and 343.3 kPa after hydrophobically modifying the gelatin with octanoyl and decanoyl aldehydes, respectively. The gelatin-based hydrogels also demonstrated a macroporous structure, excellent biocompatibility, and a good anti-inflammatory effect. The developed hydrogels accelerated wound healing in Sprague Dawley rat skin full-thickness wound models.
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(This article belongs to the Special Issue Design and Development of Gelatin-Based Materials)
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Adsorption Efficiency of Cadmium (II) by Different Alkali-Activated Materials
by
Nataša Mladenović Nikolić, Ljiljana Kljajević, Snežana S. Nenadović, Jelena Potočnik, Sanja Knežević, Sabina Dolenec and Katarina Trivunac
Gels 2024, 10(5), 317; https://doi.org/10.3390/gels10050317 - 5 May 2024
Abstract
The objective of this study was to demonstrate the potential utilization of fly ash (FA), wood ash (WA), and metakaolin (MK) in developing new alkali-activated materials (AAMs) for the removal of cadmium ions from waste water. The synthesis of AAMs involved the dissolution
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The objective of this study was to demonstrate the potential utilization of fly ash (FA), wood ash (WA), and metakaolin (MK) in developing new alkali-activated materials (AAMs) for the removal of cadmium ions from waste water. The synthesis of AAMs involved the dissolution of solid precursors, FA, WA, and MK, by a liquid activator (Na2SiO3 and NaOH). In concentrated solutions of the activator, the formation of an aluminosilicate gel structure occurred. DRIFT spectroscopy of the AAMs indicated main vibration bands between 1036 cm−1 and 996 cm−1, corresponding to Si-O-Si/Si-O-Al bands. Shifting vibration bands were seen at 1028 cm−1 to 1021 cm−1, indicating that the Si-O-Si/Si-O-Al bond is elongating, and the bond angle is decreasing. Based on the X-ray diffraction results, alkali-activated samples consist of an amorphous phase and residual mineral phases. The characteristic “hump” of an amorphous phase in the range from 20 to 40° 2θ was observed in FA and in all AWAFA samples. By the XRD patterns of the AAMs obtained by the activation of a solid three-component system, a new crystalline phase, gehlenite, was identified. The efficiency of AAMs in removing cadmium ions from aqueous solutions was tested under various conditions. The highest values of adsorption capacity, 64.76 mg/g (AWAFA6), 67.02 mg/g (AWAFAMK6), and 72.84 mg/g mg/g (AWAMK6), were obtained for materials activated with a 6 M NaOH solution in the alkali activator. The Langmuir adsorption isotherm and pseudo-second kinetic order provided the best fit for all investigated AAMs.
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(This article belongs to the Special Issue Physical and Mechanical Properties of Polymer Gels (2nd Edition))
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Active Media Perfusion in Bioprinted Highly Concentrated Collagen Bioink Enhances the Viability of Cell Culture and Substrate Remodeling
by
Denisa Kanokova, Roman Matejka, Margit Zaloudkova, Jan Zigmond, Monika Supova and Jana Matejkova
Gels 2024, 10(5), 316; https://doi.org/10.3390/gels10050316 - 5 May 2024
Abstract
The bioprinting of high-concentrated collagen bioinks is a promising technology for tissue engineering and regenerative medicine. Collagen is a widely used biomaterial for bioprinting because of its natural abundance in the extracellular matrix of many tissues and its biocompatibility. High-concentrated collagen hydrogels have
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The bioprinting of high-concentrated collagen bioinks is a promising technology for tissue engineering and regenerative medicine. Collagen is a widely used biomaterial for bioprinting because of its natural abundance in the extracellular matrix of many tissues and its biocompatibility. High-concentrated collagen hydrogels have shown great potential in tissue engineering due to their favorable mechanical and structural properties. However, achieving high cell proliferation rates within these hydrogels remains a challenge. In static cultivation, the volume of the culture medium is changed once every few days. Thus, perfect perfusion is not achieved due to the relative increase in metabolic concentration and no medium flow. Therefore, in our work, we developed a culture system in which printed collagen bioinks (collagen concentration in hydrogels of 20 and 30 mg/mL with a final concentration of 10 and 15 mg/mL in bioink) where samples flow freely in the culture medium, thus enhancing the elimination of nutrients and metabolites of cells. Cell viability, morphology, and metabolic activity (MTT tests) were analyzed on collagen hydrogels with a collagen concentration of 20 and 30 mg/mL in static culture groups without medium exchange and with active medium perfusion; the influence of pure growth culture medium and smooth muscle cells differentiation medium was next investigated. Collagen isolated from porcine skins was used; every batch was titrated to optimize the pH of the resulting collagen to minimize the difference in production batches and, therefore, the results. Active medium perfusion significantly improved cell viability and activity in the high-concentrated gel, which, to date, is the most limiting factor for using these hydrogels. In addition, based on SEM images and geometry analysis, the cells remodel collagen material to their extracellular matrix.
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(This article belongs to the Special Issue Latest Advances and Prospects of Hydrogels for Biomedical Applications)
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Investigations on the Impact of a Series of Alkoxysilane Precursors on the Structure, Morphology and Wettability of an Established Zirconium-Modified Hybrid Anticorrosion Sol–Gel Coating
by
H. Alwael, E. MacHugh, M. S. El-Shahawi and M. Oubaha
Gels 2024, 10(5), 315; https://doi.org/10.3390/gels10050315 - 5 May 2024
Abstract
The current study reports on the impact of a series of functional alkoxysilanes on the wettability and structure of a well-established silicon/zirconium hybrid anticorrosion sol–gel coating. The selected functional alkoxysilanes comprise tetra ethylorthosilicate (TEOS), 3-glycidyloxypropyltrimethoxysilane (GPTMS), 3-aminopropyltriethoxysilane (APTES) and vinyltriethoxysilane (VTES) and are
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The current study reports on the impact of a series of functional alkoxysilanes on the wettability and structure of a well-established silicon/zirconium hybrid anticorrosion sol–gel coating. The selected functional alkoxysilanes comprise tetra ethylorthosilicate (TEOS), 3-glycidyloxypropyltrimethoxysilane (GPTMS), 3-aminopropyltriethoxysilane (APTES) and vinyltriethoxysilane (VTES) and are incorporated at various concentrations (1, 5, 10 and 20%) within the silicon/zirconium sol–gel material. The prepared materials are successfully processed as coatings and cured at different temperatures in the range of 100–150 °C. The characterisation of the structures and surfaces is performed by dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), silicon nuclear magnetic resonance spectroscopy (29Si-NMR), atomic force microscopy (AFM) and static water contact angle (WCA). Structural characterisations (DLS, FTIR,29Si-NMR) show that the functional alkoxysilanes effectively bind at the surface of the reference sol–gel material, resulting in the formation of functional core–shell nanoparticles. WCA results show that the hydrophobic properties of all materials decrease with curing temperature, and AFM analysis demonstrated that this behaviour is associated with a decrease in roughness. The physico-chemical processes taking place are critically assigned and discussed.
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(This article belongs to the Special Issue Multifunctional Polymer Nano-, Micro- and Hydro- Gels: Synthesis, Properties and Applications)
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Open AccessArticle
Production and Physicochemical Characterization of the Gel Obtained in the Fermentation Process of Blue Corn Flour (Zea mays L.) with Colletotrichum gloeosporioides
by
Guadalupe Villarreal-Rodríguez, Jesús Manuel Escajeda-García, Lingyun Chen, Nubia Amaya-Olivas, Teresita Ruiz-Anchondo, David Neder-Suarez, David Chávez-Flores, Néstor Gutierrez-Mendez and León Hernández-Ochoa
Gels 2024, 10(5), 314; https://doi.org/10.3390/gels10050314 - 3 May 2024
Abstract
Food gels are viscoelastic substances used in various gelled products manufactured around the world. Polysaccharides are the most common food gelling agents. The aim of this work was the production and characterization of a gel produced in a blue corn flour fermentation process,
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Food gels are viscoelastic substances used in various gelled products manufactured around the world. Polysaccharides are the most common food gelling agents. The aim of this work was the production and characterization of a gel produced in a blue corn flour fermentation process, where different proportions were used of blue corn (Zea mays L.) flour and Czapek Dox culture medium (90 mL of culture medium with 10 g of blue corn flour, 80 mL of culture medium with 20 g of blue corn flour, and 70 mL of culture medium with 30 g of blue corn flour) and were fermented for three different durations (20, 25, and 30 days) with the Colletotrichum gloeosporioides fungus. A characterization of the gel was carried out studying the rheological properties, proximal analysis, toxicological analysis, microscopic structure, and molecular characterization, in addition to a solubility test with three different organic solvents (ethanol, hexane, and ethyl acetate, in addition to water). The results obtained showed in the rheological analysis that the gel could have resistance to high temperatures and a reversible behavior. The gel is soluble in polar solvents (ethanol and water). The main chemical components of the gel are carbohydrates, especially polysaccharides, and it was confirmed by FT-IR spectroscopy that the gel may be composed of pectin.
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(This article belongs to the Special Issue Food Gels: Properties and Applications)
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Open AccessArticle
The Time–Temperature Superposition of Polymeric Rubber Gels Treated by Means of the Mode-Coupling Theory
by
Domenico Mallamace, Giuseppe Mensitieri, Martina Salzano de Luna and Francesco Mallamace
Gels 2024, 10(5), 313; https://doi.org/10.3390/gels10050313 - 3 May 2024
Abstract
Viscoelastic relaxation measurements on styrene-butadiene rubbers (SBRs) doped with carbon nanotube (CNT) at different concentrations around the sol-gel transition show the time–temperature superposition (TTS). This process is described in terms of the mode coupling theory (MCT) approach to viscoelasticity by considering the frequency
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Viscoelastic relaxation measurements on styrene-butadiene rubbers (SBRs) doped with carbon nanotube (CNT) at different concentrations around the sol-gel transition show the time–temperature superposition (TTS). This process is described in terms of the mode coupling theory (MCT) approach to viscoelasticity by considering the frequency behavior of the loss modulus and showing that the corresponding TTS is linked to decay. From the analysis of the obtained data, we observe that the interaction between SBRs and CNT determines different levels of decay according to their concentration. Systems with the lowest CNT concentration are only characterized in the studied T-range by their fragile glass-forming behavior. However, at a specific temperature , those with the highest CNT concentration show a crossover towards pure Arrhenius that, according to the MCT, indicates the presence of kinetic glass transition (KGT), where system response functions are characterized by scaling behaviors.
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(This article belongs to the Section Gel Processing and Engineering)
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Open AccessReview
OnyxTMGel or Coil versus Hydrogel as Embolic Agents in Endovascular Applications: Review of the Literature and Case Series
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Paolo Perri, Giuseppe Sena, Paolo Piro, Tommaso De Bartolo, Stefania Galassi, Davide Costa and Raffaele Serra
Gels 2024, 10(5), 312; https://doi.org/10.3390/gels10050312 - 2 May 2024
Abstract
This review focuses on the use of conventional gel or coil and “new” generation hydrogel used as an embolic agent in endovascular applications. In general, embolic agents have deep or multidistrict vascular penetration properties as they ensure complete occlusion of vessels by exploiting
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This review focuses on the use of conventional gel or coil and “new” generation hydrogel used as an embolic agent in endovascular applications. In general, embolic agents have deep or multidistrict vascular penetration properties as they ensure complete occlusion of vessels by exploiting the patient’s coagulation system, which recognises them as substances foreign to the body, thus triggering the coagulation cascade. This is why they are widely used in the treatment of endovascular corrections (EV repair), arteriovenous malformations (AVM), endoleaks (E), visceral aneurysms or pseudo-aneurysms, and embolisation of pre-surgical or post-surgical (iatrogenic) lesions. Conventional gels such as Onyx or coils are now commercially available, both of which are frequently used in endovascular interventional procedures, as they are minimally invasive and have numerous advantages over conventional open repair (OR) surgery. Recently, these agents have been modified and optimised to develop new embolic substances in the form of hydrogels based on alginate, chitosan, fibroin and other polymers to ensure embolisation through phase transition phenomena. The main aim of this work was to expand on the data already known in the literature concerning the application of these devices in the endovascular field, focusing on the advantages, disadvantages and safety profiles of conventional and innovative embolic agents and also through some clinical cases reported. The clinical case series concerns the correction and exclusion of endoleak type I or type II appeared after an endovascular procedure of exclusion of aneurysmal abdominal aortic (EVAR) with a coil (coil penumbra released by a LANTERN microcatheter), the exclusion of renal arterial malformation (MAV) with a coil (penumbra coil released by a LANTERN microcatheter) and the correction of endoleak through the application of Onyx 18 in the arteries where sealing by the endoprosthesis was not guaranteed.
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(This article belongs to the Special Issue Latest Advances and Prospects of Hydrogels for Biomedical Applications)
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Open AccessArticle
Characterization and Performance Analysis of Hydrolyzed versus Non-Hydrolyzed Poly(NVF-co-HEA) Hydrogels for Cosmetic Applications
by
Maytinee Yooyod, Thanyaporn Pinthong, Sararat Mahasaranon, Jarupa Viyoch, Sukunya Ross and Gareth M. Ross
Gels 2024, 10(5), 311; https://doi.org/10.3390/gels10050311 - 2 May 2024
Abstract
This study explores the synthesis and modification of poly(N-vinylformamide-co-N-hydroxyethyl acrylamide) (poly(NVF-co-HEA)) hydrogels for cosmetic applications. Poly(NVF-co-HEA) hydrogels were produced followed by an acid hydrolysis reaction to produce poly(NVF-co-VAm-co-HEA) hydrogels, introducing poly(vinyl amine) (PVAm) into the structure. This modification considerably alters the hydrogels’ properties,
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This study explores the synthesis and modification of poly(N-vinylformamide-co-N-hydroxyethyl acrylamide) (poly(NVF-co-HEA)) hydrogels for cosmetic applications. Poly(NVF-co-HEA) hydrogels were produced followed by an acid hydrolysis reaction to produce poly(NVF-co-VAm-co-HEA) hydrogels, introducing poly(vinyl amine) (PVAm) into the structure. This modification considerably alters the hydrogels’ properties, yielding materials with over 96% water content, predominantly in the form of non-freezing or free water, which is beneficial in the uptake and release of hydrophilic species. The primary amine groups from inclusion of VAm also improved the mechanical properties, as evidenced by an 8-fold increase in Young’s modulus. The hydrogels also possessed pH-responsive behavior, which was particularly noticeable under acidic and basic conditions, where a large decrease in water content was observed (40% to 75% reduction). Characterizing the hydrogels’ release capabilities involved using organic dyes of different functional groups and sizes to examine the pH impact on release. The results indicated that hydrolyzed hydrogels interacted more effectively with charged species, highlighting their suitability for pH-responsive delivery. The release of cosmetic active ingredients was also demonstrated through the controlled release of Liquid Azelaic™, specifically potassium azeloyl diglycinate (PAD). Our findings reveal that the hydrolyzed hydrogels exhibit superior burst release, especially under alkaline conditions, suggesting their suitability for cosmetic applications where controlled, pH-responsive delivery of active ingredients is desired. Overall, this investigation highlights the potential of hydrolyzed poly(NVF-co-HEA) hydrogels in cosmetic applications. Their ability to combine high water content with mechanical integrity, along with their pH-responsive release ability, allows for use in cosmetic formulations.
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(This article belongs to the Section Gel Analysis and Characterization)
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Open AccessEditorial
Editorial for the Special Issue Entitled “Recent Advances in Crosslinked Gels”
by
Melike Firlak Demirkan and John G. Hardy
Gels 2024, 10(5), 310; https://doi.org/10.3390/gels10050310 - 2 May 2024
Abstract
A gel can be defined as a semi-solid structure that has mechanical properties ranging from tough to soft, depending on their constituents [...]
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(This article belongs to the Special Issue Recent Advances in Crosslinked Gels)
Open AccessFeature PaperArticle
Heat-Induced Gelation of Chickpea and Faba Bean Flour Ingredients
by
Anna Mengozzi, Emma Chiavaro, Davide Barbanti and Francesca Bot
Gels 2024, 10(5), 309; https://doi.org/10.3390/gels10050309 - 1 May 2024
Abstract
This study aimed to investigate the gelling behavior of faba bean (FB) and chickpea (CP) flour between 10 and 20% (w/w) concentration at pH 3.0, 5.0, and 7.0. Both sources formed at pH 3.0 and 5.0 self-standing gels with 12% (
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This study aimed to investigate the gelling behavior of faba bean (FB) and chickpea (CP) flour between 10 and 20% (w/w) concentration at pH 3.0, 5.0, and 7.0. Both sources formed at pH 3.0 and 5.0 self-standing gels with 12% (w/w) of flour, while 16% (w/w) of flour was required to obtain a gel at pH 7.0. During gelling between 40 and 70 °C, a sharp increase of the elastic modulus G′ was observed in both flours, mainly due to water absorption and swelling of the starch, one of the major constituents in the ingredients. Increasing the temperature at 95 °C, G′ increased due to the denaturation of globulins and therefore the exposure of their internal part, which allowed more hydrophobic interactions and the formation of the gel. After cooling, both FB and CP gels displayed a solid-like behavior (tan δ ranging between 0.11 and 0.18) with G′ values at pH 3.0 and 5.0 significantly (p < 0.05) higher than those at pH 7.0, due to the lower electrostatic repulsions at pHs far from the isoelectric point. The rheological properties were supported by the water binding capacity values, confirming the better gels’ strength described by rheological analysis. These results will enhance our understanding of the role of legume flours in formulating innovative and sustainable food products as alternatives to animal ones.
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(This article belongs to the Special Issue Recent Advances in Food Gels)
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Open AccessFeature PaperArticle
Characterization of Quaternary-Ammonium-Based Ionogel Membranes for Application in Proton Exchange Membrane Fuel Cells
by
Eduardo Iniesta-López, Adrián Hernández-Fernández, Ángel Martínez-López, Yolanda Garrido, Antonia Pérez de los Ríos and Francisco José Hernández-Fernández
Gels 2024, 10(5), 308; https://doi.org/10.3390/gels10050308 - 1 May 2024
Abstract
In recent years, the quest to advance fuel cell technologies has intensified, driven by the imperative to reduce reliance on hydrocarbon-derived fuels and mitigate pollutant emissions. Proton exchange membranes are a critical material of fuel cell technologies. The potential of ionic liquid-based polymer
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In recent years, the quest to advance fuel cell technologies has intensified, driven by the imperative to reduce reliance on hydrocarbon-derived fuels and mitigate pollutant emissions. Proton exchange membranes are a critical material of fuel cell technologies. The potential of ionic liquid-based polymer inclusion membranes or ionogels for proton exchange membrane fuel cells (PEMFCs) has recently appeared. Thermal stability, SEM-EDX characterization, NMR and IR characterization, thermogravimetric analysis, ion exchange capacity, and water uptake are key properties of these membranes which need to be investigated. In this work, ionogel based on quaternary ammonium salts, such as [N8,8,8,1+][Cl−], [N8,8,8,1+][Br−], and [N8-10,8-10,8-10,1+][Cl−] in various compositions with poly(vinyl chloride) are extensively studied and characterized based on those key properties. The best properties were obtained when a quaternary ammonium cation was combined with a bromide anion. Finally, ionogels are tested in microbial fuel cells. Microbial fuel cells based on the ionogel reach a maximum of 147 mW/m2, which represents 55% of the reference membrane (Nafion 212). These results indicate that we still have the possibility of improvement through the appropriate selection of the cation and anion of the ionic liquid. Overall, the promise of ionogel membranes as a viable alternative in fuel cell applications has been demonstrated.
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(This article belongs to the Special Issue Synthetic, Natural and Hybrid Gels Intended for Various Applications)
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Open AccessArticle
Rheological and Injectability Evaluation of Sterilized Poloxamer-407-Based Hydrogels Containing Docetaxel-Loaded Lipid Nanoparticles
by
Ana Camila Marques, Paulo C. Costa, Sérgia Velho and Maria Helena Amaral
Gels 2024, 10(5), 307; https://doi.org/10.3390/gels10050307 - 1 May 2024
Abstract
Nanostructured lipid carriers (NLCs) have the potential to increase the bioavailability and reduce the side effects of docetaxel (DTX). However, only a small fraction of nanoparticles given intravenously can reach a solid tumor. In situ-forming gels combined with nanoparticles facilitate local administration and
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Nanostructured lipid carriers (NLCs) have the potential to increase the bioavailability and reduce the side effects of docetaxel (DTX). However, only a small fraction of nanoparticles given intravenously can reach a solid tumor. In situ-forming gels combined with nanoparticles facilitate local administration and promote drug retention at the tumor site. Injectable hydrogels based on poloxamer 407 are excellent candidates for this hybrid nanoparticle–hydrogel system because of their thermoresponsive behavior and biocompatibility. Therefore, this work aimed to develop injectable poloxamer hydrogels containing NLCs for intratumoral delivery of DTX. To ensure sterility, the obtained hydrogels were autoclaved (121 °C for 15 min) after preparation. Then, the incorporation of NLCs into the poloxamer hydrogels and the impact of steam sterilization on the nanocomposite hydrogels were evaluated concerning sol–gel transition, injectability, and physicochemical stability. All formulations were extruded through the tested syringe–needle systems with acceptable force (2.2–13.4 N) and work (49.5–317.7 N·mm) of injection. Following steam sterilization, injection became easier in most cases, and the physicochemical properties of all hydrogels remained practically unchanged according to the spectroscopical and thermal analysis. The rheological evaluation revealed that the nanocomposite hydrogels were liquid at 25 °C and underwent rapid gelation at 37 °C. However, their sterilized counterparts gelled at 1–2 °C above body temperature, suggesting that the autoclaving conditions employed had rendered these nanocomposite hydrogels unsuitable for local drug delivery.
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(This article belongs to the Special Issue Advances in Functional Gel (2nd Edition))
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Size Control of Carbon Xerogel Spheres as Key Factor Governing the H2O2 Selectivity in Metal-Free Bifunctional Electro-Fenton Catalysts for Tetracycline Degradation
by
Edgar Fajardo-Puerto, Nerea López-García, Abdelhakim Elmouwahidi, Esther Bailón-García, Francisco Carrasco-Marín, Lilian D. Ramírez-Valencia and Agustín F. Pérez-Cadenas
Gels 2024, 10(5), 306; https://doi.org/10.3390/gels10050306 - 1 May 2024
Abstract
Carbon xerogel spheres co-doped with nitrogen and eco-graphene were synthesized using a typical solvothermal method. The results indicate that the incorporation of eco-graphene enhances the electrochemical properties, such as the current density (JK) and the selectivity for the four transferred electrons
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Carbon xerogel spheres co-doped with nitrogen and eco-graphene were synthesized using a typical solvothermal method. The results indicate that the incorporation of eco-graphene enhances the electrochemical properties, such as the current density (JK) and the selectivity for the four transferred electrons (n). Additionally, nitrogen doping has a significant effect on the degradation efficiency, varying with the size of the carbon xerogel spheres, which could be attributed to the type of nitrogenous group doped in the carbon material. The degradation efficiency improved in the nanometric spheres (48.3% to 61.6%) but decreased in the micrometric-scale spheres (58.6% to 53.4%). This effect was attributed to the N-functional groups present in each sample, with N-CNS-5 exhibiting a higher percentage of graphitic nitrogen (35.7%) compared to N-CMS-5 (15.3%). These findings highlight the critical role of sphere size in determining the type of N-functional groups present in the sample. leading to enhanced degradation of pollutants as a result of the electro-Fenton process.
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(This article belongs to the Special Issue Synthesis, Properties and Applications of Carbon Aerogel)
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