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Volume 10
Issue 11
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Gels, Volume 10, Issue 11 (November 2024) – 80 articles

Cover Story (view full-size image): Swelling and compression tests were performed on gelatin–alginate-based scaffolds. The evolution of the hydrogels’ components and their densities were measured, and the molar properties of the interstitial fluid were determined. Hyperelastic parameter identification based on constitutive models of the rubber elasticity theory was performed, yielding a macromolecular description of the strain energy density function. The obtained network structural parameters were employed in the equilibrium swelling equation to determine the polymer–solvent interaction parameter. The results show that the average mesh size defines the friction coefficient and can be regarded as a concentration-dependent characteristic length that connects non-linear elasticity with inherent visco-elasticity through hysteresis, which quantifies the total dissipated energy. View this paper
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23 pages, 10821 KiB  
Article
Poly(Vinyl Alcohol) Drug and PVA–Drug–Surfactant Complex Organogel with Dimethyl Sulfoxide as a Drug Delivery System
by Sabina Otarbayeva and Dmitriy Berillo
Gels 2024, 10(11), 753; https://doi.org/10.3390/gels10110753 - 20 Nov 2024
Viewed by 431
Abstract
The relevance of active research lies in the need to develop new technologies to improve drug delivery methods for the effective treatment of wound healing. Additionally, the potential application of organogels in other areas of biomedicine, such as creating medical patches with controlled [...] Read more.
The relevance of active research lies in the need to develop new technologies to improve drug delivery methods for the effective treatment of wound healing. Additionally, the potential application of organogels in other areas of biomedicine, such as creating medical patches with controlled drug delivery, indicates a wide range of possibilities for using this technology. This study focuses on developing controlled drug delivery systems using organogels as carriers for ceftriaxone and ofloxacin. By selecting optimal formulations, organogels were created to immobilize the drugs, facilitating their effective and sustained release. The swelling behavior of the hydrogels was studied, showing a swelling coefficient between 16 and 32%, indicating their ability to absorb liquid relative to their weight. Drug release studies demonstrated that ceftriaxone was released 1.8 times slower than ofloxacin, ensuring a more controlled delivery. Microbiological tests confirmed that the organogels containing ofloxacin exhibited antimicrobial activity against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. However, it was a challenge to estimate activity for the model antibiotic ceftriaxone due to bacterial resistance to it. Organogel poly(vinyl alcohol) (PVA)-DMSO–alginate modifications with surfactant cetylpyridinium bromide led to the formation of a polyelectrolyte complex on the interphase, allowing further enhanced the prolonged release of the drugs. The research identified that the optimal compositions for sustained drug release were organogels with compositions PVA (10%)-PVP (1%) DMSO (50%) and PVA (10%)-DMSO (50%) formulations, illustrating the transparent nature of these organogels making them suitable for ophthalmological application. Various organogels compositions (PVA-DMSO, PVA-poly(vinylpyrrolidone)-DMSO, PVA-DMSO–alginate, PVA-DMSO-PLGA, PVA-DMSO–drug–surfactant) loaded with ceftriaxone, ofloxacin, and surfactant were prepared and characterized, highlighting their potential use in antibiotic patches for wound healing. These organogels illustrate promising results for localized treatment of infections in wounds, cuts, burns, and other skin lesions. Full article
(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property and Biomedical Application (2nd Edition))
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25 pages, 7612 KiB  
Article
Development of Alginate Composite Microparticles for Encapsulation of Bifidobacterium animalis subsp. lactis
by Marko Vinceković, Lana Živković, Elmira Turkeyeva, Botagoz Mutaliyeva, Galiya Madybekova, Suzana Šegota, Nataša Šijaković Vujičić, Anđela Pustak, Tanja Jurkin, Marta Kiš and Sanja Kajić
Gels 2024, 10(11), 752; https://doi.org/10.3390/gels10110752 - 19 Nov 2024
Viewed by 664
Abstract
The probiotic bacterium Bifidobacterium animalis subsp. lactis BB-12 (BB-12) was encapsulated in two composites, alginate/agar and alginate/agar/casein. The network structure and physicochemical properties of these composites are influenced by complex interactions, including hydrogen bonding, electrostatic forces between biopolymers, calcium ions, and the encapsulated [...] Read more.
The probiotic bacterium Bifidobacterium animalis subsp. lactis BB-12 (BB-12) was encapsulated in two composites, alginate/agar and alginate/agar/casein. The network structure and physicochemical properties of these composites are influenced by complex interactions, including hydrogen bonding, electrostatic forces between biopolymers, calcium ions, and the encapsulated bacteria. The composites demonstrated a granular surface, with the granules being spatially oriented on the alginate/agar/BB-12 surface and linearly oriented on the alginate/agar/casein/BB-12 surface. They possess a highly organized microparticle structure and exhibit viscoelastic solid-like behavior. The alginate/agar/BB-12 composite showed higher storage modulus, shear stress, and shear strain values, indicating enhanced stability in various physical environments. Both composites displayed good thermal stability, aligning with their rheological properties, confirming their well-ordered structures. Despite differences in composite structures, the release mechanism of bacteria is governed by Fickian diffusion through the composite matrix. Based on physicochemical properties, the alginate/agar/casein composite is recommended for dairy product fermentation, while the alginate/agar composite seems more suitable for oral use. These findings provide new insights into the interactions between bacterial cultures and alginate composite ingredients. Full article
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20 pages, 3272 KiB  
Article
Crosslinking by Click Chemistry of Hyaluronan Graft Copolymers Involving Resorcinol-Based Cinnamate Derivatives Leading to Gel-like Materials
by Mario Saletti, Simone Pepi, Marco Paolino, Jacopo Venditti, Germano Giuliani, Claudia Bonechi, Gemma Leone, Agnese Magnani, Claudio Rossi and Andrea Cappelli
Gels 2024, 10(11), 751; https://doi.org/10.3390/gels10110751 - 19 Nov 2024
Viewed by 481
Abstract
The well-known “click chemistry” reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) was used to transform under very mild conditions hyaluronan-based graft copolymers HA(270)-FA-Pg into the crosslinked derivatives HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL. In particular, medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted at [...] Read more.
The well-known “click chemistry” reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) was used to transform under very mild conditions hyaluronan-based graft copolymers HA(270)-FA-Pg into the crosslinked derivatives HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL. In particular, medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted at various extents (i.e., 10, 20, and 40%) with fluorogenic ferulic acid (FA) residue bonding propargyl groups were used in the CuAAC reaction with novel azido-terminated crosslinking agents Tri(Ethylene Glycol) Ethyl Resorcinol Acrylate (TEGERA) and Hexa(Ethylene Glycol) Ethyl Resorcinol Acrylate (HEGERA). The resulting HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL materials were characterized from the point of view of their structure by performing NMR studies. Moreover, the swelling behavior and rheological features were assessed employing TGA and DSC analysis to evaluate the potential gel-like properties of the resulting crosslinked materials. Despite the 3D crosslinked structure, HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL frameworks showed adequate swelling performance, the required shear thinning behavior, and coefficient of friction values close to those of the main commercial HA solutions used as viscosupplements (i.e., 0.20 at 10 mm/s). Furthermore, the presence of a crosslinked structure guaranteed a longer residence time. Indeed, HA(270)-FA-TEGERA-CL-40 and HA(270)-FA-HEGERA-CL-40 after 48 h showed a four times greater enzymatic resistance than the commercial viscosupplements. Based on the promising obtained results, the crosslinked materials are proposed for their potential applicability as novel viscosupplements. Full article
(This article belongs to the Special Issue Polymeric Hydrogels for Biomedical Application)
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16 pages, 3322 KiB  
Article
Wound Healing Potential of Herbal Hydrogel Formulations of Cedrus brevifolia Extracts in Mice
by Georgia Lyggitsou, Christina Barda, Maria Anagnostou, Andreas Douros, Dimitra Statha, Christina Karampasi, Anastasia Ioanna Papantonaki, Ioannis Svoliantopoulos, Ioannis Sfiniadakis, Andreas Vitsos, Helen Skaltsa and Michail Ch. Rallis
Gels 2024, 10(11), 750; https://doi.org/10.3390/gels10110750 - 19 Nov 2024
Viewed by 419
Abstract
Wound healing stands as a paramount therapeutic pursuit, imposing significant challenges on healthcare, particularly for vulnerable populations. Cedrus brevifolia, a species endemic to Cyprus, thrives in the Tripylos region, commonly known as Cedar Valley, within the Paphos forest. Despite its endemism, this [...] Read more.
Wound healing stands as a paramount therapeutic pursuit, imposing significant challenges on healthcare, particularly for vulnerable populations. Cedrus brevifolia, a species endemic to Cyprus, thrives in the Tripylos region, commonly known as Cedar Valley, within the Paphos forest. Despite its endemism, this species exhibits negligible genetic divergence from its Mediterranean related species. This study aims to investigate the potential of C. brevifolia resin and bark extracts in promoting wound healing in a mouse model. Previous in vitro investigations have elucidated the antioxidant and anti-inflammatory potential of extracts and isolates derived from the title plant, warranting further exploration in an in vivo setting. This experimental design employed 40 male SKH-hr2 black and brown mice aged 2–4 months. Wounds measuring 1 cm2 were meticulously induced in the anesthetized mice and the potential healing effect of the herbal hydrogel formulations was evaluated. The healing potential of the C. brevifolia extracts was rigorously assessed through the daily application of gel formulations containing resin concentrations of 5% and 10% w/w, alongside sapwood and heartwood extracts at concentrations of 0.5% and 1% w/w. The evaluation of the treatments encompassed a multifaceted approach, incorporating clinical observations, skin biophysical parameter assessments utilizing an Antera 3D camera, and FT-IR spectroscopy, in addition to histopathological examination. The chemical compositions were also investigated through NMR and bio-guided isolation. The most prominent herbal hydrogel preparation proved to be the 10% resin, followed by the sapwood at 1%. The chemical analysis unveiled abietic acid, manool, and lariciresinol derivatives that potentially contributed to the observed results. Bridging the gap between in vitro observations and in vivo outcomes attempts to shed light on the potential therapeutic benefits of C. brevifolia hydrogels in wound care. Full article
(This article belongs to the Special Issue Advanced Gel-Based Materials and Coatings with Enhanced Bioactivity)
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12 pages, 35977 KiB  
Article
Organogels of FmocFF: Exploring the Solvent-Dependent Gelmorphic Behavior
by Basanta Saikia, Dong Chen, Yovan de Coene and Stijn Van Cleuvenbergen
Gels 2024, 10(11), 749; https://doi.org/10.3390/gels10110749 - 19 Nov 2024
Viewed by 442
Abstract
FmocFF (9-fluorenyl methoxycarbonyl-phenylalanine) is an extensively studied low-molecular-weight hydrogel. Although there have been numerous studies on FmocFF hydrogel, its potential to form organogels has not been well explored. In this work, we systematically explore the organogels of FmocFF in a wide range of [...] Read more.
FmocFF (9-fluorenyl methoxycarbonyl-phenylalanine) is an extensively studied low-molecular-weight hydrogel. Although there have been numerous studies on FmocFF hydrogel, its potential to form organogels has not been well explored. In this work, we systematically explore the organogels of FmocFF in a wide range of organic solvents. FmocFF is found to be a robust organogeltor, and the subsequent organogels exhibit diverse gelmorphic behavior exhibiting various degrees of crystallinity and morphology depending on the solvent used. The mechanical strength of the organogels is evaluated using rheology. A novel technique, in situ SHG microscopy, is introduced to study the gel structure in its native state. In addition to the solvent–solute interactions that are typically used to predict gelmorphic behavior, we observed indications that the degree of crystallinity also plays a significant role in determining the mechanical properties and structure of FmocFF organogels. Full article
(This article belongs to the Special Issue Thixotropic Gels: Mechanisms, Functions and Applications)
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21 pages, 5560 KiB  
Article
Hypoxia Preconditioned Serum Hydrogel (HPS-H) Accelerates Dermal Regeneration in a Porcine Wound Model
by Jun Jiang, Tanita Man, Manuela Kirsch, Samuel Knoedler, Kirstin Andersen, Judith Reiser, Julia Werner, Benjamin Trautz, Xiaobin Cong, Selma Forster, Sarah Alageel, Ulf Dornseifer, Arndt F. Schilling, Hans-Günther Machens, Haydar Kükrek and Philipp Moog
Gels 2024, 10(11), 748; https://doi.org/10.3390/gels10110748 - 17 Nov 2024
Viewed by 384
Abstract
Harnessing the body’s intrinsic resources for wound healing is becoming a rapidly advancing field in regenerative medicine research. This study investigates the effects of the topical application of a novel porcine Hypoxia Preconditioned Serum Hydrogel (HPS-H) on wound healing using a minipig model [...] Read more.
Harnessing the body’s intrinsic resources for wound healing is becoming a rapidly advancing field in regenerative medicine research. This study investigates the effects of the topical application of a novel porcine Hypoxia Preconditioned Serum Hydrogel (HPS-H) on wound healing using a minipig model over a 21-day period. Porcine HPS exhibited up to 2.8× elevated levels of key angiogenic growth factors (VEGF-A, PDGF-BB, and bFGF) and demonstrated a superior angiogenic effect in a tube formation assay with human umbilical endothelial cells (HUVECs) in comparison to porcine normal serum (NS). Incorporating HPS into a hydrogel carrier matrix (HPS-H) facilitated the sustained release of growth factors for up to 5 days. In the in vivo experiment, wounds treated with HPS-H were compared to those treated with normal serum hydrogel (NS-H), hydrogel only (H), and no treatment (NT). At day 10 post-wounding, the HPS-H group was observed to promote up to 1.7× faster wound closure as a result of accelerated epithelialization and wound contraction. Hyperspectral imaging revealed up to 12.9% higher superficial tissue oxygenation and deep perfusion in HPS-H-treated wounds at day 10. The immunohistochemical staining of wound biopsies detected increased formation of blood vessels (CD31), lymphatic vessels (LYVE-1), and myofibroblasts (alpha-SMA) in the HPS-H group. These findings suggest that the topical application of HPS-H can significantly accelerate dermal wound healing in an autologous porcine model. Full article
(This article belongs to the Special Issue Gel-Based Novel Wound Dressing)
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26 pages, 22121 KiB  
Article
Developing Innovative Apolar Gels Based on Cellulose Derivatives for Cleaning Metal Artworks
by Andrea Macchia, Camilla Zaratti, Davide Ciogli, Giovanni Rivici, Silvia Pilati, Nereo Sbiri, Tilde de Caro and Maria Assunta Navarra
Gels 2024, 10(11), 747; https://doi.org/10.3390/gels10110747 - 16 Nov 2024
Viewed by 363
Abstract
The use of organic solvents, particularly those of a non-polar nature, is a common practice during cleaning operations in the restoration of polychrome artworks and metallic artifacts. However, these solvents pose significant risks to the health of operators and the environment. This study [...] Read more.
The use of organic solvents, particularly those of a non-polar nature, is a common practice during cleaning operations in the restoration of polychrome artworks and metallic artifacts. However, these solvents pose significant risks to the health of operators and the environment. This study explores the formulation of innovative gels based on non-polar solvents and cellulose derivatives, proposing a safe and effective method for cleaning metallic artworks. The study is focused on a toxic apolar solvent, Ligroin, identified as one of the most widely used solvents in the cultural heritage treatments, and some “green” alternatives such as Methyl Myristate and Isopropyl Palmitate. The main challenge lies in overcoming the chemical incompatibility between non-polar solvents and polar thickening agents like cellulose ethers. To address this problem, the research was based on a hydrophilic–lipophilic balance (HLB) system and Hansen solubility parameters (HSPs) to select appropriate surfactants, ensuring the stability and effectiveness of the formulated gels. Stability, viscosity, and solvent release capacity of gels were analyzed using Static Light Multiple Scattering (Turbiscan), viscometry, and thermogravimetric analysis (TGA). The efficacy of cleaning in comparison with Ligroin liquid was evaluated on a metal specimen treated with various apolar protective coatings used commonly in the restoration of metallic artifacts, such as microcrystalline waxes (Reswax, Soter), acrylic resins (Paraloid B44), and protective varnishes (Incral, Regalrez). Multispectral analysis, digital optical microscopy, FTIR spectroscopy, and spectrocolorimetry allowed for the assessment of the gels’ ability to remove the different protective coatings, the degree of cleaning achieved, and the presence of any residues. The results obtained highlight the ability of the formulated gels to effectively remove protective coatings from metallic artifacts. Cetyl Alcohol proved to be the most versatile surfactant to realize a stable and efficient gel. The gels based on Methyl Myristate and Isopropyl Palmitate showed promising results as “green” alternatives to Ligroin, although in some cases, they exhibited less selectivity in the removal of protective coatings. Full article
(This article belongs to the Special Issue Design of Supramolecular Hydrogels)
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18 pages, 4485 KiB  
Article
Novel Liposome–Gel Formulations Containing a Next Generation Postbiotic: Characterization, Rheological, Stability, Release Kinetic, and In Vitro Antimicrobial Activity Studies
by Halise Betül Gökçe and İsmail Aslan
Gels 2024, 10(11), 746; https://doi.org/10.3390/gels10110746 - 15 Nov 2024
Viewed by 270
Abstract
In recent years, in addition to the positive effects of probiotics and prebiotics on health, increasing research has shown that postbiotics also have significant potential in the health field. Postbiotics are bioactive components produced by probiotic bacteria during fermentation and may exhibit antimicrobial [...] Read more.
In recent years, in addition to the positive effects of probiotics and prebiotics on health, increasing research has shown that postbiotics also have significant potential in the health field. Postbiotics are bioactive components produced by probiotic bacteria during fermentation and may exhibit antimicrobial activity. This study investigated the antimicrobial effects of liposomal postbiotics formulated in gel. Various postbiotic-containing liposomal systems have been developed and optimized to prepare formulations. Optimized liposomes and liposomal postbiotic-containing gel forms were examined in terms of particle size, polydispersity index, zeta potential, structural properties, encapsulation efficiency, permeability, release profiles, and stability. Finally, the antimicrobial activities of the postbiotics and the optimum gel formulation LG1 were evaluated on Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Enterococcus hirae, and Candida albicans strains using disk diffusion and microdilution methods. The optimum liposome formulation L1 was determined to have a particle size of 185.32 ± 0.80 nm, a polydispersity index of 0.206 ± 0.012, a zeta potential of 35.0 ± 0.5 mV, and an encapsulation efficiency of 17.52%. Its permeability was determined as 51.52% at the end of 6 h. In vitro release studies showed that the drug release profile was in accordance with first-order kinetics and suitable for controlled release. The findings show that formulated postbiotics have similar antimicrobial activity to free postbiotics. These results suggest that liposomal gel formulations support the antimicrobial effects of postbiotics while providing advantages of use. In conclusion, the findings contribute to a better understanding of the antimicrobial potential of postbiotics and lipogelosomal postbiotics and optimize their use in pharmaceutical applications. Full article
(This article belongs to the Special Issue Liposomal and Ethosomal Gels: From Design to Application (2nd Edition))
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17 pages, 3557 KiB  
Article
In Vitro Investigation of 3D Printed Hydrogel Scaffolds with Electrospun Tidemark Component for Modeling Osteochondral Interface
by Victoria Effiong Effanga, Dana Akilbekova, Fariza Mukasheva, Xiao Zhao, Dilhan M. Kalyon and Cevat Erisken
Gels 2024, 10(11), 745; https://doi.org/10.3390/gels10110745 - 15 Nov 2024
Viewed by 383
Abstract
Osteochondral (OC) tissue plays a crucial role due to its ability to connect bone and cartilage tissues. To address the complexity of structure and functionality at the bone–cartilage interface, relevant to the presence of the tidemark as a critical element at the bone–cartilage [...] Read more.
Osteochondral (OC) tissue plays a crucial role due to its ability to connect bone and cartilage tissues. To address the complexity of structure and functionality at the bone–cartilage interface, relevant to the presence of the tidemark as a critical element at the bone–cartilage boundary, we fabricated graded scaffolds through sequential 3D printing. The scaffold’s bottom layer was based on a gelatin/oxidized alginate mixture enriched with hydroxyapatite (HAp) to create a rougher surface and larger pores to promote osteogenesis. In contrast, the upper layer was engineered to have smaller pores and aimed to promote cartilage tissue formation and mimic the physical properties of the cartilage. An electrospun ε-polycaprolactone (PCL) membrane with micrometer-range pores was incorporated between the layers to replicate the function of tidemark—a barrier to prevent vascularization of cartilage from subchondral bone tissue. In vitro cell studies confirmed the viability of the cells on the layers of the scaffolds and the ability of PCL mesh to prevent cellular migration. The fabricated scaffolds were thoroughly characterized, and their mechanical properties were compared to native OC tissue, demonstrating suitability for OC tissue engineering and graft modeling. The distance of gradient of mineral concentration was found to be 151 µm for grafts and the native OC interface. Full article
(This article belongs to the Special Issue Recent Advances in Multi-material Hydrogel Bioinks for 3D Bioprinting)
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14 pages, 2109 KiB  
Article
Effect of Freezing Temperature on the Thermal, Rheological, and Gelatinization Properties of Freeze-Thaw-Dehydrated Potato Powder
by Xinyan Duan, Tingting Zhang, Qiannan Liu, Liang Zhang, Wei Liu, Ruixuan Zhao and Honghai Hu
Gels 2024, 10(11), 744; https://doi.org/10.3390/gels10110744 - 15 Nov 2024
Viewed by 232
Abstract
To promote the application of freeze-thaw-dehydrated (FTD) potatoes and their gels, this study aimed to investigate the effects of freezing temperature on the physicochemical and gel properties of FTD potato powder and their correlation. The results revealed that, as the freezing temperature decreased, [...] Read more.
To promote the application of freeze-thaw-dehydrated (FTD) potatoes and their gels, this study aimed to investigate the effects of freezing temperature on the physicochemical and gel properties of FTD potato powder and their correlation. The results revealed that, as the freezing temperature decreased, the solubility exhibited an overall downwards trend resulting from soluble solids and amylose liberation. Owing to the better cell integrity at −20 °C, the solubility was greater than that of the other treatment groups. In contrast, the trough viscosity and melting enthalpy increased, and the final viscosity, and setback first increased but then decreased. Regarding the properties of the FTD potato powder gel, the storage modulus, loss modulus, hardness, adhesiveness, chewiness, and consistency first increased but then decreased with decreasing freezing temperature. At a moderate freezing temperature (−20 °C), the solubility and stability of the FTD potato powder were well maintained, and the final viscosity, setback, and hardness reached their highest values. Correlation analysis revealed that, with decreasing freezing temperature, the amount of FTD potato powder initially increased, followed by a decrease in the final viscosity and setback. This trend was positively correlated with the hardness of the FTD potato gel (r = 0.98, r = 0.93). Full article
(This article belongs to the Special Issue Food Gels: Structures, Properties and Applications)
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19 pages, 12677 KiB  
Article
A Simple Preparation of Crosslinked, Highly Alkaline Diallyldimethylammonium Hydroxide Hydrogel Particles via Inverse Static Anion Exchange
by Tim B. Mrohs and Oliver Weichold
Gels 2024, 10(11), 743; https://doi.org/10.3390/gels10110743 - 15 Nov 2024
Viewed by 229
Abstract
Highly alkaline hydrogels are gaining increasing attention in building materials research. Specifically, cationic alkaline hydrogels based on diallyldimethylammonium hydroxide (DADMAOH) as the monomer have been effectively used to seal water-bearing cracks or serve as coupling media for electrochemical chloride extraction. However, the residual [...] Read more.
Highly alkaline hydrogels are gaining increasing attention in building materials research. Specifically, cationic alkaline hydrogels based on diallyldimethylammonium hydroxide (DADMAOH) as the monomer have been effectively used to seal water-bearing cracks or serve as coupling media for electrochemical chloride extraction. However, the residual halogen content and challenges in scaling up monomer production have hindered broader application. Attempts to use a commercially available cation-selective membrane for ion exchange achieved up to 90% chloride-to-hydroxide switch, but the approach proved ineffective due to significant monomer decomposition during the process. By contrast, neutral gels and gel particles can be readily prepared from diallyldimethylammonium chloride (DADMAC) in large quantities and with a wide range of compositions. It is demonstrated here that these neutral gel particles undergo inverse static anion exchange when suspended in NaOH solution, generating DADMAOH particles with residual halide contents of <0.3%, without the need for ion-selective or dialysis membranes. This corresponds to an up to 100-fold reduction in residual chloride content compared to particles produced directly from alkaline monomer solutions, thereby significantly enhancing the efficiency of hydroxide ion release. The swelling behaviour of the particles is primarily influenced by the initial monomer concentration, while conductivity remains largely unaffected, indicating that charge transport occurs mainly along the particle surface. Despite the pronounced increase in swelling with decreasing particle radii, the specific conductivity of 2.8 Ω−1 m−1 is still sufficient for their use as coupling media in concrete applications. In summary, the alkaline particles prepared via inverse static anion exchange meet all necessary requirements for building materials applications, offering a broader range of tuneable properties and greater ease of production compared to gels or particles derived from DADMAOH. Full article
(This article belongs to the Special Issue Synthesis and Applications of Hydrogels (2nd Edition))
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14 pages, 3000 KiB  
Article
Preparation and Characterization of Temperature-Sensitive Gel Plugging Agent
by Fengbao Liu, Da Yin, Jinsheng Sun, Xiao Luo and Xianbin Huang
Gels 2024, 10(11), 742; https://doi.org/10.3390/gels10110742 - 15 Nov 2024
Viewed by 418
Abstract
In order to use intelligent gel systems to realize deep source water control in medium and high water cut reservoirs, and also to solve the shortcomings of conventional gels, such as the high chemical dose required, large profile control radius, poor temperature resistance, [...] Read more.
In order to use intelligent gel systems to realize deep source water control in medium and high water cut reservoirs, and also to solve the shortcomings of conventional gels, such as the high chemical dose required, large profile control radius, poor temperature resistance, shear resistance, and plugging performance, a temperature-sensitive gel based on natural cellulose was developed, and the temperature resistance, rheological performance, and plugging performance of the temperature-sensitive gel were tested and evaluated. The results show that the system can maintain a viscosity retention rate of up to 95% after high-temperature aging at 90–120 °C for 50 days. When using medium- to low-salinity calcium chloride formation water for preparation, the gelation effect is good. The rheometer oscillation frequency scanning test shows that the system gel is a strong elastic body dominated by elasticity. The core displacement experiment shows that the highest sealing rate of the system is 97%, and the breakthrough pressure can reach 2.5 MPa at this time. The microstructure of the gel system was tested by infrared, and it was found that the gel system had strong hydrogen bonding and the gel had good stability. The research results contribute to improving the recovery rate of high water cut oil reservoirs. Full article
(This article belongs to the Section Gel Analysis and Characterization)
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18 pages, 4818 KiB  
Article
Investigation of In Situ Gelation Behavior and Enhanced Oil Recovery Ability of Polymer Gel Used for Controlling CO2 Channeling in Tight Fractured Reservoir
by Hong He, Yibo Liu, Guang Zhao, Yifei Liu, Haihua Pei and Wei Zhou
Gels 2024, 10(11), 741; https://doi.org/10.3390/gels10110741 - 14 Nov 2024
Viewed by 371
Abstract
Polymer gels are one of the most common plugging agents used for controlling CO2 channeling and improving sweep efficiency and oil recovery in tight fractured reservoirs. However, the in situ gelation behavior and enhanced oil recovery ability of polymer gel in fractured [...] Read more.
Polymer gels are one of the most common plugging agents used for controlling CO2 channeling and improving sweep efficiency and oil recovery in tight fractured reservoirs. However, the in situ gelation behavior and enhanced oil recovery ability of polymer gel in fractured porous media is still unclear. Thus, in this study, the bulk and in situ gelation behavior of crosslinked phenolic resin gel in a long stainless microtube as the fractured porous media was investigated. The enhanced oil recovery ability of phenolic resin gel used for CO2 channeling was investigated by means of a fractured core model. Results show that, with the increase of polymer and crosslinker concentrations, the bulk gelation time shortens and gel strength improves during the static gelation process. With the increase of polymer concentration and temperature, the in situ static gelation time and dynamic gelation time of the gel system in the microtube are shortened, and the breakthrough pressure gradient increases after gelation. Compared with the in situ static gelation behavior, the in situ dynamic gelation time is prolonged and the breakthrough pressure gradient decreases after gelation. The in situ static gelation time in the microtube is 1.2 times that of bulk gelation time in an ampoule bottle, and the in situ dynamic gelation time is nearly 3 times that of ampoule bottles. When the injected slug volume was 1.0 FV (fracture volume), as the polymer concentration increased from 3000 mg·L−1 to 4000 mg·L−1, the incremental oil recovery increased from 3.53% to 4.73%. Full article
(This article belongs to the Special Issue Polymer Gels for the Oil and Gas Industry)
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20 pages, 4790 KiB  
Article
Development and Quality Enhancement of Fried Fish Cake Prototype with Transglutaminase, Trehalose, and Herbal Oil for Room Temperature Distribution
by Ye Youl Kim, Khawaja Muhammad Imran Bashir, Seonyeong Kang, Yongjoon Park, Jae Hak Sohn and Jae-Suk Choi
Gels 2024, 10(11), 740; https://doi.org/10.3390/gels10110740 - 14 Nov 2024
Viewed by 331
Abstract
This study focuses on developing a fried fish cake prototype with improved quality and extended shelf-life, enabling room-temperature distribution through an innovative high-temperature and high-process retort method. Surimi-based products typically necessitate cold storage and a refrigerated distribution system, affecting their physical properties and [...] Read more.
This study focuses on developing a fried fish cake prototype with improved quality and extended shelf-life, enabling room-temperature distribution through an innovative high-temperature and high-process retort method. Surimi-based products typically necessitate cold storage and a refrigerated distribution system, affecting their physical properties and flavor while escalating costs. By incorporating Transglutaminase (TGase), trehalose, and herbal oils, and optimizing the heating process using the response surface methodology, this research addresses challenges related to changes in physical properties, color, and off-flavors during high-temperature and high-pressure treatment. The addition of 0.37% ACTIVA-K TGase significantly enhanced gel strength by promoting protein cross-linking, while 0.75% trehalose improved color stability by suppressing browning, thus enhancing visual appeal. A 0.1% concentration of bay oil effectively enhanced the flavor profile by masking undesirable odors without compromising the sensory quality. Optimized processing conditions maximized DPPH radical scavenging activity, whiteness, and gel strength, ensuring superior product quality and safety. Nutritional analysis confirmed a balanced composition of moisture, protein, essential amino acids, and minerals, in accordance with Korean national standards for acid values. Microstructural examination revealed a uniform network structure, contributing to excellent texture and sensory evaluations. Shelf-life predictions indicated a storage duration of approximately 19 months, surpassing commercially available products and offering a competitive edge. This novel approach allows surimi-based products to be stored and distributed at room temperature, while also providing the potential for increased profitability. Full article
(This article belongs to the Special Issue Recent Advances on the Use of Different Gels Type in the Food Industry)
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19 pages, 3340 KiB  
Article
Lidocaine-Loaded Thermoresponsive Gel for Accelerated Wound Healing in Dry Socket and Oral Wounds
by Nuttawut Supachawaroj, Kunchorn Kerdmanee and Sucharat Limsitthichaikoon
Gels 2024, 10(11), 739; https://doi.org/10.3390/gels10110739 - 14 Nov 2024
Viewed by 375
Abstract
Dry socket, also known as alveolar osteitis, presents significant challenges in oral surgery because of severe pain and delayed wound healing. This study aims to address these challenges by developing and evaluating a lidocaine-loaded polyelectrolyte complex thermoresponsive gel (LG) designed to enhance wound [...] Read more.
Dry socket, also known as alveolar osteitis, presents significant challenges in oral surgery because of severe pain and delayed wound healing. This study aims to address these challenges by developing and evaluating a lidocaine-loaded polyelectrolyte complex thermoresponsive gel (LG) designed to enhance wound healing and provide effective pain management in oral wounds. The thermoresponsive gel transitions from a liquid to a gel at body temperature, ensuring sustained contact with the wound site and prolonged release of lidocaine. The in vitro assessments, including cytotoxicity and wound scratch assays, demonstrated the biocompatibility and therapeutic potential of the LG formulation. Following this, palatal wounds were induced in rats, with healing monitored over a 14-days period. Histological analyses were conducted to assess tissue regeneration and inflammation. The results indicated that the LG formulation significantly improved wound closure rates, reduced inflammation, and accelerated epithelialization compared with control groups, primarily because of the high content of hyaluronic acid (HA). The synergistic effects of HA combined with the thermoresponsive properties of the gel facilitated faster healing. These findings suggest that LG is a promising therapeutic option for enhancing oral wound healing and effectively managing pain, particularly in conditions such as dry socket. Full article
(This article belongs to the Special Issue Advanced Gel-Based Materials and Coatings with Enhanced Bioactivity)
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13 pages, 3187 KiB  
Article
Enhancing Medium-Chain Fatty Acid Delivery Through Bigel Technology
by Manuela Machado, Eduardo M. Costa, Sara Silva, Sérgio C. Sousa, Ana Maria Gomes and Manuela Pintado
Gels 2024, 10(11), 738; https://doi.org/10.3390/gels10110738 - 14 Nov 2024
Viewed by 335
Abstract
This study presents the development and characterization of medium-chain fatty acid (MCFA)-loaded bigels, using coconut oil as the MCFA source. The bigels exhibited high oil binding capacity, ranging from 87% to 98%, effectively retaining MCFAs within the matrix, with lauric acid (C12) being [...] Read more.
This study presents the development and characterization of medium-chain fatty acid (MCFA)-loaded bigels, using coconut oil as the MCFA source. The bigels exhibited high oil binding capacity, ranging from 87% to 98%, effectively retaining MCFAs within the matrix, with lauric acid (C12) being the main component detected within the bigels at 178.32 ± 0.10 mg/g. Physicochemical analysis, including FTIR and scanning electron microscopy, confirmed stable fatty acid incorporation and a cohesive, smooth structure. The FTIR spectra displayed O-H and C=O stretching vibrations, indicating hydrogen bonding within the matrix, while the SEM images showed uniform lipid droplet distribution with stable phase separation. Thermal stability tests showed that the bigels were stable for 5 days at 50 °C, with oil retention and structural integrity unchanged. Rheological testing indicated a solid-like behavior, with a high elastic modulus (G′) that consistently exceeded the viscous modulus (G″), which is indicative of a strong internal structure. In simulated gastrointestinal digestion, the bigels achieved significantly higher MCFA retention than the pure oil, particularly in the gastric phase, with recovery percentages of 38.1% for the bigels and 1.7% for the oil (p < 0.05), suggesting enhanced bioavailability. Cell-based cytotoxicity assays showed low cytotoxicity, and permeability testing in a co-culture Caco-2/HT29-MTX model revealed a controlled, gradual MCFA release, with approximately 10% reaching the basolateral side over 6 h. These findings highlight MCFA-loaded bigels as a promising platform for nutraceutical applications; they provided stability, safety, and controlled MCFA release, with significant potential for functional foods aimed at enhancing fatty acid bioavailability. Full article
(This article belongs to the Special Issue Gel Technology for Development of Bioactive Foodstuffs)
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21 pages, 2634 KiB  
Article
Effect of the Ratio of Protein to Water on the Weak Gel Nonlinear Viscoelastic Behavior of Fish Myofibrillar Protein Paste from Alaska Pollock
by Timilehin Martins Oyinloye and Won Byong Yoon
Gels 2024, 10(11), 737; https://doi.org/10.3390/gels10110737 - 13 Nov 2024
Viewed by 377
Abstract
The linear and nonlinear rheological behaviors of fish myofibrillar protein (FMP) paste with 75%, 82%, and 90% moisture content were evaluated using small-amplitude oscillatory shear (SAOS) and large-amplitude oscillatory shear (LAOS) tests. SAOS revealed pastes with 75% and 82% moisture exhibited solid-like behavior, [...] Read more.
The linear and nonlinear rheological behaviors of fish myofibrillar protein (FMP) paste with 75%, 82%, and 90% moisture content were evaluated using small-amplitude oscillatory shear (SAOS) and large-amplitude oscillatory shear (LAOS) tests. SAOS revealed pastes with 75% and 82% moisture exhibited solid-like behavior, characterized by higher storage modulus (G′) than loss modulus (G″), indicative of weak gel properties with a strong protein interaction. In contrast, the 90% moisture content showed more viscous behavior due to weakened protein–protein entanglements. The frequency exponent (n′ and n″) from the power law equation varied slightly (0.24 to 0.36), indicating limited sensitivity to changes in deformation rate during SAOS. LAOS tests revealed significant structural changes, with Lissajous–Bowditch curves revealing early nonlinearities at 10% strain for 90% moisture content. Decomposed Chebyshev coefficients (e3/e1, v3/v1, S, and T) indicated strain stiffening at lower strains for the 75% and 82% moisture pastes (i.e., < 50% strain for 75% and < 10% strain for 82%), transitioning to strain thinning at higher strains. Additionally, numerical model confirmed the predictability of the 3D printing process from the nonlinear rheological data, confirmed the suitability of the 75% and 82% moisture pastes for applications requiring structural integrity. These insights are essential for optimizing processing conditions in industrial applications. The findings suggest that the 75% and 82% moisture pastes are suitable for applications requiring structural integrity, while the 90% moisture paste is ideal for flow-based processes. These insights are essential for optimizing processing conditions in industrial applications. Full article
(This article belongs to the Special Issue Food Gel-Based Systems: Gel-Forming and Food Applications)
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20 pages, 5385 KiB  
Article
Studies on the Powerful Photoluminescence of the Lu2O3:Eu3+ System in the Form of Ceramic Powders and Crystallized Aerogels
by Alan D. Alcantar Mendoza, Antonieta García Murillo, Felipe de J. Carrillo Romo and José Guzmán Mendoza
Gels 2024, 10(11), 736; https://doi.org/10.3390/gels10110736 - 13 Nov 2024
Viewed by 379
Abstract
This study compared the chemical, structural, and luminescent properties of xerogel-based ceramic powders (CPs) with those of a new series of crystallized aerogels (CAs) synthesized by the epoxy-assisted sol–gel process. Materials with different proportions of Eu3+ (2, 5, 8, and 10 mol%) [...] Read more.
This study compared the chemical, structural, and luminescent properties of xerogel-based ceramic powders (CPs) with those of a new series of crystallized aerogels (CAs) synthesized by the epoxy-assisted sol–gel process. Materials with different proportions of Eu3+ (2, 5, 8, and 10 mol%) were synthesized in Lu2O3 host matrices, as well as a Eu2O3 matrix for comparative purposes. The products were analyzed by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), photoluminescence analysis, and by the Brunauer–Emmett–Teller (BET) technique. The results show a band associated with the M-O bond, located at around 575 cm−1. XRD enabled us to check two ensembles: matrices (Lu2O3 or Eu2O3) and doping (Lu2O3:Eu3+) with appropriate chemical compositions featuring C-type crystal structures and intense reflections by the (222) plane, with an interplanar distance of around 0.3 nm. Also, the porous morphology presented by the materials consisted of interconnected particles that formed three-dimensional networks. Finally, emission bands due to the energy transitions (5DJ, where J = 0, 1, 2, and 3) were caused by the Eu3+ ions. The samples doped at 10 mol% showed orange-pink photoluminescence and had the longest disintegration times and greatest quantum yields with respect to the crystallized Eu2O3 aerogel. Full article
(This article belongs to the Special Issue Gel-Based Materials: Preparations and Characterization (2nd Edition))
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24 pages, 6049 KiB  
Review
Food Gels Based on Polysaccharide and Protein: Preparation, Formation Mechanisms, and Delivery of Bioactive Substances
by Yong Guo, Chao Ma, Yan Xu, Lianxin Du and Xin Yang
Gels 2024, 10(11), 735; https://doi.org/10.3390/gels10110735 - 13 Nov 2024
Viewed by 504
Abstract
Hydrogels have a unique three-dimensional network that can create a good environment for the loading of functional compounds; hence, they have considerable potential in the delivery of bioactive substances. Natural macromolecular substances (proteins, polysaccharides) have the features of low toxicity, degradability, and biosafety; [...] Read more.
Hydrogels have a unique three-dimensional network that can create a good environment for the loading of functional compounds; hence, they have considerable potential in the delivery of bioactive substances. Natural macromolecular substances (proteins, polysaccharides) have the features of low toxicity, degradability, and biosafety; thus, they can be employed in the manufacture of hydrogels in the food sector. With its customizable viscoelastic and porous structure, hydrogels are believed to be good bioactive material delivery vehicles, which can effectively load polyphenols, vitamins, probiotics, and other active substances to prevent their influence from the external environment, thereby improving its stability. In this research, the common raw materials, preparation methods, and applications in the delivery of bioactive elements of food gels were examined; this study aimed at presenting new ideas for the development and utilization of protein-based food gels. Full article
(This article belongs to the Special Issue Food Gels: Structure and Function)
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16 pages, 3540 KiB  
Article
Cryostructuring of Polymeric Systems: 68. Evaluation of Poly(vinyl alcohol) Composite Cryogels Filled with Poly(3-hydroxybutyric acid)-Based Microspheres of Different Porous Morphology as Potential Delivery Systems for Drugs of Various Water-Solubility
by Dmitrii A. Michurov, Gagik A. Andreasyan and Vladimir I. Lozinsky
Gels 2024, 10(11), 734; https://doi.org/10.3390/gels10110734 - 13 Nov 2024
Viewed by 390
Abstract
Poly(3-hydroxybutyric acid)-based microspheres of two types, with and without macropores, were prepared; their morphology and particle size were evaluated. These microspheres were entrapped as disperse fillers into the bulk of macroporous cryogels based on poly(vinyl alcohol) (PVA). It was found that the rigidity [...] Read more.
Poly(3-hydroxybutyric acid)-based microspheres of two types, with and without macropores, were prepared; their morphology and particle size were evaluated. These microspheres were entrapped as disperse fillers into the bulk of macroporous cryogels based on poly(vinyl alcohol) (PVA). It was found that the rigidity of the resultant composite cryogels increased markedly as compared to that of unfilled cryogels of the same PVA concentration. The resulting composites were further tested for their potential to act as drug carriers. With that, simvastatin was included into the filler particles directly in the course of their preparation, followed by entrapment of such drug-loaded microspheres into the PVA cryogel. In turn, ibuprofen sodium salt was introduced into the preliminary prepared cryogels filled with the drug-free microspheres. The experimental study of drug release kinetics showed that due to the non-covalent interactions of both simvastatin and ibuprofen sodium salt with the particles of discrete phase, prolongation of the release processes was observed. Full article
(This article belongs to the Special Issue Biopolymer Gel-Assisted Synthesis of Particles for Biomedical Applications (2nd Edition))
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20 pages, 6207 KiB  
Article
Egg White-Based Gels with Candelilla Wax: A Study of Rheological, Mechanical, Calorimetric and Microstructural Properties
by Iram Cisneros-García, Ma. de la Paz Salgado-Cruz, Alitzel B. García-Hernández, Gustavo F. Gutiérrez-López, Humberto Hernández-Sánchez, Brenda H. Camacho-Díaz and Liliana Alamilla-Beltrán
Gels 2024, 10(11), 733; https://doi.org/10.3390/gels10110733 - 13 Nov 2024
Viewed by 478
Abstract
Bigels (BGs) are innovative composite systems that integrate oleogel and hydrogel structures, and are gaining increasing attention for their unique textural and functional properties in food applications. This study evaluated the rheological and mechanical properties of egg white-based bigels incorporating candelilla wax (CW) [...] Read more.
Bigels (BGs) are innovative composite systems that integrate oleogel and hydrogel structures, and are gaining increasing attention for their unique textural and functional properties in food applications. This study evaluated the rheological and mechanical properties of egg white-based bigels incorporating candelilla wax (CW) as an oleogelator. The results indicate that different egg white protein (EWP) (5–10%) concentrations and hydrogel-to-oleogel ratios (20:80 to 80:20) significantly influenced the structural and functional properties of the bigels. Compression testing revealed no significant differences in strength across the tested range; however, higher EWP concentrations enhanced the stability of the BGs. Furthermore, increased candelilla wax oleogel (CWO) content (60%) markedly improved emulsion stability, resulting in superior strength, as confirmed by dynamic light scattering. Rheological studies demonstrated shear-thinning behavior, particularly at higher hydrogel content related to the oleogel (W/O), which exhibited the highest yield stress. Microstructural investigations confirmed the presence of a continuous oleogel phase within the bigels (W/O) and revealed the formation of a complex structure. These findings suggest that a reduced hydrogel-to-oleogel ratio can be utilized across various food systems, opening new possibilities for creating customized food structures with desirable textural and functional attributes. Full article
(This article belongs to the Special Issue Functionality of Oleogels and Bigels in Foods)
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16 pages, 2576 KiB  
Article
Tailoring of the Properties of Amorphous Mesoporous Titanosilicates Active in Acetone Condensation
by Vera R. Bikbaeva, Anna S. Artem’eva, Sergey V. Bubennov, Alexander I. Nikiforov, Viktor Y. Kirsanov, Dmitry V. Serebrennikov, Lubov F. Korzhova, Stanislav G. Karchevsky, Leonard M. Khalilov, Boris I. Kutepov and Nellia G. Grigoreva
Gels 2024, 10(11), 732; https://doi.org/10.3390/gels10110732 - 12 Nov 2024
Viewed by 473
Abstract
Amorphous mesoporous materials are promising as catalysts for processes involving or forming bulk molecules. In a reaction such as acetone condensation to form mesitylene, an effective catalyst should not only have a developed porous structure but also have active centers of acidic and [...] Read more.
Amorphous mesoporous materials are promising as catalysts for processes involving or forming bulk molecules. In a reaction such as acetone condensation to form mesitylene, an effective catalyst should not only have a developed porous structure but also have active centers of acidic and basic types. The sol–gel approach allows one to obtain titanosilicates with such characteristics. This work demonstrates the possibility of controlling their properties by varying the conditions for the synthesis of titanosilicate gels. It has been established that controlling hydrolysis allows one to increase the activity of amorphous mesoporous titanosilicates by 10 times: from acetone conversion of 6% to 60%. It has been shown that the use of titanium acetylacetonate complexes in the synthesis of gels leads to an increase in the content of tetracoordinated Ti in the structure and contributes to an increase in the acidity of titanosilicates. During the condensation of acetone on the obtained mesoporous titanosilicates, high acetone conversion (60–79%) and mesitylene selectivity of up to 83% were achieved. Full article
(This article belongs to the Special Issue Advances in Functional Gel (2nd Edition))
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15 pages, 1343 KiB  
Article
Kinetic and Mechanistic Release Studies on Hyaluronan Hydrogels for Their Potential Use as a pH-Responsive Drug Delivery Device
by Saliha Erikci, Niklas van den Bergh and Heike Boehm
Gels 2024, 10(11), 731; https://doi.org/10.3390/gels10110731 - 12 Nov 2024
Viewed by 559
Abstract
Hyaluronic acid, a biocompatible polymer, holds significant potential for drug delivery applications. Its variable degree of protonation, which entails tunable physical properties, makes it an ideal candidate for developing pH-sensitive hydrogels. Like other smart drug delivery systems, pH-responsive hydrogels can enhance medical treatment [...] Read more.
Hyaluronic acid, a biocompatible polymer, holds significant potential for drug delivery applications. Its variable degree of protonation, which entails tunable physical properties, makes it an ideal candidate for developing pH-sensitive hydrogels. Like other smart drug delivery systems, pH-responsive hydrogels can enhance medical treatment and expedite the healing process. However, the inherent complexity of hydrogels poses challenges in identifying suitable matrix systems. This study evaluates the potential of thiolated hyaluronic acid hydrogels, physically cross-linked with deacetylated disaccharide units of the polymer, for use in drug delivery. Using low-molecular-weight dextrans as model drugs, we investigated the system’s response to different pH environments in terms of swelling as well as the kinetic and mechanistic release of the encapsulated compound. The data suggest tunable release properties of the gel regarding drug size and pH value. Our results demonstrate the gel system’s potential for smart drug delivery. We anticipate that this system is a promising candidate for use in transdermal wound healing applications and strongly encourage further investigations using other sorts of (model) drugs to gain a more detailed insight into its pH-responsive transport qualities. Full article
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14 pages, 6190 KiB  
Article
Formulation of Emulgels Containing Clotrimazole for the Treatment of Vaginal Candidiasis
by Zsófia Vilimi, Márton Király, Ádám Tibor Barna, Zsófia Edit Pápay, Lívia Budai, Krisztina Ludányi, Nikolett Kállai-Szabó and István Antal
Gels 2024, 10(11), 730; https://doi.org/10.3390/gels10110730 - 12 Nov 2024
Viewed by 496
Abstract
Vaginal candidiasis poses significant health concerns that affect approximately 75% of women globally and often leads to discomfort and a decrease in quality of life. Traditional treatments, despite their effectiveness, may cause discomfort and adverse effects, such as vaginal discharge, bleeding, and dryness, [...] Read more.
Vaginal candidiasis poses significant health concerns that affect approximately 75% of women globally and often leads to discomfort and a decrease in quality of life. Traditional treatments, despite their effectiveness, may cause discomfort and adverse effects, such as vaginal discharge, bleeding, and dryness, promoting the exploration of alternative formulations. In this study, we aimed to develop a novel therapeutic approach for the treatment of vaginal candidiasis utilizing oleic acid containing emulgels made from thermoresponsive poloxamer-based hydrogels. These emulgels were designed to provide a sustained release of clotrimazole, an antifungal agent. Incorporating oleic acid enhanced the drug’s solubility and contributed to vaginal health. The formulations were characterized by their rheological properties, in vitro release, mucoadhesion, and spreadability. We conducted rheological measurements on the hydrogels that served as the base for the emulgels, as well as on the emulgels themselves. The emulgels exhibited continuous rheological behavior with changing temperatures, making them suitable for storage at room temperature. With an increasing HPMC content, we achieved enhanced mucoadhesion, which is beneficial for formulations used in body cavities. Moreover, in vitro release studies revealed sustained drug release profiles, which can be adjusted by varying the ratios of poloxamers and HPMC. These findings suggest that the developed emulgels offer a promising therapeutic option for vaginal candidiasis, addressing both the symptoms and the treatment of discomfort. Full article
(This article belongs to the Special Issue Recent Advances in Hydrogels for Biomedical Application)
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19 pages, 5118 KiB  
Article
Marine Resources Gels as Main Ingredient for Wound Healing Biomaterials: Obtaining and Characterization
by Alina Elena Coman, Maria Minodora Marin, Ana Maria Roșca, Madalina Georgiana Albu Kaya, Rodica Roxana Constantinescu and Irina Titorencu
Gels 2024, 10(11), 729; https://doi.org/10.3390/gels10110729 - 11 Nov 2024
Viewed by 426
Abstract
The skin, known as the largest organ of the body, is essential for maintaining physiological balance and acts as a barrier against the external environment. When skin becomes damaged and wounds appear on the skin’s surface, a complex healing process, involving multiple types [...] Read more.
The skin, known as the largest organ of the body, is essential for maintaining physiological balance and acts as a barrier against the external environment. When skin becomes damaged and wounds appear on the skin’s surface, a complex healing process, involving multiple types of cells and microenvironments, take place. Selecting a suitable dressing for a wound is crucial for accelerating healing, reducing treatment costs, and improving the patient’s overall health. Starting from natural resources such as perch skin (P. fluviatilis), this article aims to develop biocompatible materials for regenerative medicine from collagen in the form of gels/gelatines. The extracted gels were physical/chemical and structurally analyzed. In order to obtain collagen scaffolds for wound healing, the extracted collagen gels from perch skin were further freeze-dried. The ability of these scaffolds is essential for controlling moisture levels during wound healing; therefore, it was necessary to investigate the samples’ ability to absorb water. The assessed collagen-based scaffolds were microbiologically tested, and their biocompatibility was investigated by incubating human adult dermal fibroblasts. The outcomes reveal an innovative path for the production of biomaterials used in wound healing, starting from collagen derived from marine sources. Full article
(This article belongs to the Special Issue Hydrogel for Sustained Delivery of Therapeutic Agents (2nd Edition))
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17 pages, 11316 KiB  
Article
Effects of Moisture Content and Heat Treatment on the Viscoelasticity and Gelation of Polyacrylonitrile/Dimethylsulfoxide Solutions
by Jae-Yeon Yang, Yun-Su Kuk, Byoung-Suhk Kim and Min-Kang Seo
Gels 2024, 10(11), 728; https://doi.org/10.3390/gels10110728 - 10 Nov 2024
Viewed by 414
Abstract
Polyacrylonitrile (PAN) gels create significant obstacles in industrial fiber spinning by forming insoluble networks that compromise solution stability and uniformity. This study investigates the rheological properties of PAN/dimethyl sulfoxide (DMSO) solutions, examining how aging time, moisture content, and polymer concentration affect gelation behavior. [...] Read more.
Polyacrylonitrile (PAN) gels create significant obstacles in industrial fiber spinning by forming insoluble networks that compromise solution stability and uniformity. This study investigates the rheological properties of PAN/dimethyl sulfoxide (DMSO) solutions, examining how aging time, moisture content, and polymer concentration affect gelation behavior. Dynamic rheological analysis revealed that both physical and chemical crosslinks play crucial roles in gel formation, with gelation accelerating markedly when moisture content exceeds 3% and aging progresses. Under heat treatment at 80 °C, samples with increased moisture content demonstrated rapid transitions to solid-like states, indicating a critical moisture threshold for enhanced gelation kinetics. Additionally, reductions in polymer concentration disrupted physical crosslink density, thereby mitigating gel formation. These results underscore the importance of precisely controlling moisture and concentration parameters in PAN solutions to stabilize solution properties and minimize gel formation, thus enhancing process efficiency and quality in PAN-based carbon fiber production. Full article
(This article belongs to the Special Issue Gel-Based Materials: Preparations and Characterization (2nd Edition))
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17 pages, 6687 KiB  
Article
Novel Approach to Increasing the Amplitude of the Mechanical Oscillations of Self-Oscillating Gels: Introduction of Catalysts Both as Pendant Groups and as Crosslinkers
by Ilya L. Mallphanov, Michail Y. Eroshik, Dmitry A. Safonov, Alexander V. Sychev, Vyacheslav E. Bulakov and Anastasia I. Lavrova
Gels 2024, 10(11), 727; https://doi.org/10.3390/gels10110727 - 9 Nov 2024
Viewed by 421
Abstract
For the first time, we introduced chemomechanical self-oscillating poly(N-isopropylacrylamide)-based gels containing catalytically active Fe or Ru complexes both as crosslinkers and as pendant groups. All the obtained gels exhibited sustained autonomous oscillations driven by the Belousov–Zhabotinsky reaction within their structure. The Ru complex-based [...] Read more.
For the first time, we introduced chemomechanical self-oscillating poly(N-isopropylacrylamide)-based gels containing catalytically active Fe or Ru complexes both as crosslinkers and as pendant groups. All the obtained gels exhibited sustained autonomous oscillations driven by the Belousov–Zhabotinsky reaction within their structure. The Ru complex-based gels also demonstrated pronounced chemomechanical oscillations; they periodically swelled/shrunk when the catalyst was reduced/oxidized. It was found that the combination of catalytically active cross-linking and pendant Ru complexes in the same gel led to a change in the structure of the gel and a significant increase in the amplitude of its mechanical oscillations. The proposed approach allowed for increasing the amplitude of the mechanical oscillations of self-oscillating gels and opened up new possibilities for adjusting their characteristics. We believe that these gels hold potential for the development of soft actuators and systems capable of signal processing through propagating and interacting chemical waves. Full article
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13 pages, 1137 KiB  
Article
Optimization of the Oxygen Permeability of Non-Silicone Hydrogel Contact Lenses Through Crosslinking Modifications
by Clara Lim, María García-Montero, Andrew Courtis, Paul Hainey, David Madrid-Costa and Almudena Crooke
Gels 2024, 10(11), 726; https://doi.org/10.3390/gels10110726 - 9 Nov 2024
Viewed by 459
Abstract
The main weakness of non-silicone hydrogel contact lenses is their low oxygen permeability (Dk). Hence, we have tried to optimize their Dk using various concentrations and lengths of the poly (ethylene glycol) dimethacrylate crosslinker in a mixture of N,N-Dimethylacrylamide and Cyclohexyl methacrylate monomers. [...] Read more.
The main weakness of non-silicone hydrogel contact lenses is their low oxygen permeability (Dk). Hence, we have tried to optimize their Dk using various concentrations and lengths of the poly (ethylene glycol) dimethacrylate crosslinker in a mixture of N,N-Dimethylacrylamide and Cyclohexyl methacrylate monomers. After synthesizing the different contact lenses, we evaluated their chemical, optical, and mechanical properties. The resultant non-silicone hydrogel contact lenses presented similar high water contents (75.69–80.60%) and adequate optical (e.g., a transmittance ranging from 85.91% to 99.91% and a refractive index between 1.3630 and 1.3740) and elongation at break (178.95–356.05%) characteristics for clinical applications. Conversely, they presented high contact angles (81.00–100.00°) and a low Young’s modulus (0.066–0.167 MPa). Regarding the impact of the crosslinking modifications, the water content, contact angle, refractive index, transmittance, and Young’s modulus of the synthesized lenses were slightly affected by crosslinker conditions. In contrast, the elongation at break (178.95–356.05%) and, more importantly, the oxygen permeability, which reached values of up to 73.90 Fatt units, were considerably impacted by the crosslinker conditions. To our knowledge, this study demonstrates for the first time that, in addition to water, other usual hydrogel components, like crosslinkers, can modulate the Dk of non-silicone contact lenses. It also provides a simple and scalable method to fabricate more permeable non-silicone lenses. Full article
(This article belongs to the Special Issue Recent Advances in Multi-Functional Hydrogels)
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12 pages, 2747 KiB  
Article
Evaluation of Mixing Temperature in the Preparation of Plant-Based Bigels
by Marcela Quilaqueo, Sonia Millao, Eduardo Morales, Mónica Rubilar and Ingrid Contardo
Gels 2024, 10(11), 725; https://doi.org/10.3390/gels10110725 - 9 Nov 2024
Viewed by 375
Abstract
Understanding gel structures and behavior is a prerequisite for attaining the desired food application characteristics. The mixing temperature is crucial when incorporating thermolabile active compounds into gels. This study evaluated the effect of mixing temperature on the physical and chemical properties of a [...] Read more.
Understanding gel structures and behavior is a prerequisite for attaining the desired food application characteristics. The mixing temperature is crucial when incorporating thermolabile active compounds into gels. This study evaluated the effect of mixing temperature on the physical and chemical properties of a bigel system prepared using a carnauba wax/canola oil oleogel and Arabic gum hydrogels. The results showed that bigels prepared at lower temperatures (30 and 40 °C) resulted in a solid-like state under crystallization temperature, resulting in matrices with larger hydrogel droplets, softer texture, and lower adhesiveness, spreadability, and solvent binding capacity. In contrast, bigels prepared at higher temperatures (50 and 60 °C), around crystallization temperature but with no solid state, resulted in matrices with smaller hydrogel droplets and higher firmness, adhesiveness, and spreadability. These bigels had a higher apparent viscosity, especially at lower shear rates, and solid-like behavior in the linear viscosity range. During the bigel preparation process, adjusting the mixture temperature had no effect on the samples’ oxidative stability, FTIR spectra, or thermal properties. The results highlighted the importance of hydrogel droplet size on the microstructure of the formed bigels, and smaller droplets could act as effective fillers to reinforce the matrix without making chemical changes. Full article
(This article belongs to the Special Issue Gel-Based Materials: Preparations and Characterization (2nd Edition))
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16 pages, 2213 KiB  
Article
Activated Charcoal-Alginate Platform for Simultaneous Local Delivery of Bioactive Agents: At the Nexus of Antimicrobial and Cytotoxic Activity of Zn2+ Ions
by Andrea Osmokrovic, Ivan Jancic, Zeljko Zizak, Marina Milenkovic and Bojana Obradovic
Gels 2024, 10(11), 724; https://doi.org/10.3390/gels10110724 - 8 Nov 2024
Viewed by 454
Abstract
Antimicrobial resistance (AMR) is a global public health threat that affects cancer patients more than the general population. In this work, a composite system based on Zn-alginate hydrogel and activated charcoal (AC) particles that, upon contact with physiological fluids, simultaneously releases bioactive agents [...] Read more.
Antimicrobial resistance (AMR) is a global public health threat that affects cancer patients more than the general population. In this work, a composite system based on Zn-alginate hydrogel and activated charcoal (AC) particles that, upon contact with physiological fluids, simultaneously releases bioactive agents (Zn2+ and AC particles impregnated with povidone–iodine) was designed to locally address specific problems characteristic for malignant wounds (MWs). This composite was comprehensively investigated in vitro regarding its morphology (field-emission scanning electron microscopy), Zn2+ release (flame atomic absorption spectrometry), iodine adsorption and desorption from AC particles (energy dispersive X-ray analysis and UV–visible spectroscopy) as well as its antimicrobial and antitumor activity. With respect to the ongoing AMR crises, antimicrobial activity was tested against a wide range of wild multi-drug resistant bacterial and yeast strains, all isolated from patient wounds. Since Zn2+ ions proved to be selectors of resistant strains of bacteria, the synergistic activity of AC particles and adsorbed iodine was shown to be crucial for excellent antibacterial activity. On the other hand, the synergy of AC particles and Zn2+ ions showed an equally strong antifungal effect. In addition, antimicrobial concentrations of Zn2+ ions showed cytotoxic activity against two cancer cell lines derived from cancers affecting skin either as metastatic cancer (breast cancer MDA-MB-453 cell line) or primary cancer of the skin (malignant melanoma Fem-X cell line), which enables Zn2+ ions to be further investigated as potent local agents targeting malignant cells. Full article
(This article belongs to the Special Issue Recent Research on Medical Hydrogels)
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