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Rheological and Injectability Evaluation of Sterilized Poloxamer-407-Based Hydrogels Containing Docetaxel-Loaded Lipid Nanoparticles
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Heat-Induced Gelation of Chickpea and Faba Bean Flour Ingredients
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Effect of Gold Nanoparticle Size on Regulated Catalytic Activity of Temperature-Responsive Polymer−Gold Nanoparticle Hybrid Microgels
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Facile Synthesis of Surface-Modified Hollow-Silica (SiO2) Aerogel Particles via Oil–Water–Oil Double Emulsion Method
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Dipole Theory of Polyzwitterion Microgels and Gels
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) / CiteScore - Q2 (Polymers and Plastics)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 10.9 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the first half of 2024).
- 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 Gels.
Impact Factor:
5.0 (2023);
5-Year Impact Factor:
4.9 (2023)
Latest Articles
Preparation and Performance Evaluation of a Supramolecular Polymer Gel-Based Temporary Plugging Agent for Heavy Oil Reservoir
Gels 2024, 10(8), 536; https://doi.org/10.3390/gels10080536 - 19 Aug 2024
Abstract
When encountering heavy oil reservoirs during drilling, due to the change in pressure difference inside the well, heavy oil will invade the drilling fluid, and drilling fluid will spill into the reservoir along the formation fractures, affecting the drilling process. A supramolecular polymer
[...] Read more.
When encountering heavy oil reservoirs during drilling, due to the change in pressure difference inside the well, heavy oil will invade the drilling fluid, and drilling fluid will spill into the reservoir along the formation fractures, affecting the drilling process. A supramolecular polymer gel-based temporary plugging agent was prepared using acrylamide (AM), butyl acrylate (BA), and styrene (ST) as reacting monomers, N, N-methylenebisacrylamide (MBA) as a crosslinking agent, ammonium persulfate (APS) as an initiator, and poly(vinyl alcohol) (PVA) as a non-covalent component. A supermolecular polymer gel with a temperature tolerance of 120 °C and acid solubility of 90% was developed. The experimental results demonstrated that a mechanically robust, thermally stable supramolecular polymer gel was successfully synthesized through the copolymerization of AM, BA, and ST, as well as the in situ formation hydrogen bonding between poly (AM-co-BA-co-ST) and PVA, leading to a three-dimensional entangled structure. The gel-forming solution possessed excellent gelling performance even in the presence of a high content of salt and heavy oil, demonstrating superior resistance to salt and heavy oil under harsh reservoir conditions. High-temperature and high-pressure plugging displacement experiments proved that the supramolecular polymer gel exhibited high pressure-bearing capacity, and the blocking strength reached 5.96 MPa in a wedge-shaped fracture with a length of 30 cm. Furthermore, the dissolution rate of the supramolecular polymer gel was as high as 96.2% at 120 °C for 48 h under a 15% HCl solution condition.
Full article
(This article belongs to the Special Issue Polymer Gels for the Oil and Gas Industry)
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Open AccessReview
Harnessing Biopolymer Gels for Theranostic Applications: Imaging Agent Integration and Real-Time Monitoring of Drug Delivery
by
Pranita Jirvankar, Surendra Agrawal, Nikhita Chambhare and Rishabh Agrawal
Gels 2024, 10(8), 535; https://doi.org/10.3390/gels10080535 - 14 Aug 2024
Abstract
Biopolymer gels have gained tremendous potential for therapeutic applications due to their biocompatibility, biodegradability, and ability to adsorb and bind biological fluids, making them attractive for drug delivery and therapy. In this study, the versatility of biopolymer gels is explored in theranostic backgrounds,
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Biopolymer gels have gained tremendous potential for therapeutic applications due to their biocompatibility, biodegradability, and ability to adsorb and bind biological fluids, making them attractive for drug delivery and therapy. In this study, the versatility of biopolymer gels is explored in theranostic backgrounds, with a focus on integrating imaging features and facilitating real-time monitoring of drug delivery. Different methods of delivery are explored for incorporating imaging agents into biopolymer gels, including encapsulation, surface functionalization, nanoparticle encapsulation, and layer-by-layer assembly techniques. These methods exhibit the integration of agents and real-time monitoring drug delivery. We summarize the synthesis methods, general properties, and functional mechanisms of biopolymer gels, demonstrating their broad applications as multimodal systems for imaging-based therapeutics. These techniques not only enable multiple imaging but also provide signal enhancement and facilitate imaging targets, increasing the diagnostic accuracy and therapeutic efficacy. In addition, current techniques for incorporating imaging agents into biopolymer gels are discussed, as well as their role in precise drug delivery and monitoring.
Full article
(This article belongs to the Special Issue Biopolymer Gels as Smart Drug Delivery and Theranostic Systems)
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Open AccessArticle
Blackcurrant Pomace Extract as a Natural Antioxidant in Vienna Sausages Reformulated by Replacement of Pork Backfat with Emulsion Gels Based on High Oleic Sunflower and Flaxseed Oils
by
Nicoleta Cîrstea (Lazăr), Violeta Nour, Alexandru Radu Corbu and Georgiana Gabriela Codină
Gels 2024, 10(8), 534; https://doi.org/10.3390/gels10080534 - 13 Aug 2024
Abstract
The incorporation of a blackcurrant pomace extract (BPE) at 2.5%, 5.0% and 10.0% into an emulsion gel based on high oleic sunflower and linseed oils was examined in order to obtain a functional ingredient to be used as a pork backfat replacer in
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The incorporation of a blackcurrant pomace extract (BPE) at 2.5%, 5.0% and 10.0% into an emulsion gel based on high oleic sunflower and linseed oils was examined in order to obtain a functional ingredient to be used as a pork backfat replacer in Vienna sausages. The replacement of the pork backfat with the control emulsion gel reduced the cooking loss but negatively affected the color by decreasing L* and a* values as compared with the traditional product. A decrease in the n-6/n-3 ratio from 10.99 to around 1.54 (by 7 times) was achieved through reformulation, while the PUFA/SFA ratio increased from 0.49 to 1.09. The incorporation of BPE did not have a major impact on the fatty acid profile and improved color by increasing redness, but negatively affected the texture by increasing hardness, gumminess and share force as compared with the sausages reformulated without extract. BPE reduced the pH and the thermal stability of the emulsion gels, increased cooking loss and decreased moisture retention in sausages. BPE increased the oxidative stability of Vienna sausages enriched in polyunsaturated fatty acids; however, the incorporation of BPE into the emulsion gels above 5% affected the sensory scores for appearance, texture and general acceptability of the reformulated sausages.
Full article
(This article belongs to the Special Issue Food Gels: Structure and Properties)
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Graphical abstract
Open AccessArticle
Preparation of Complex Polysaccharide Gels with Zanthoxylum bungeanum Essential Oil and Their Application in Fish Preservation
by
Shan Xue, Chao Li and Zhouyi Xiong
Gels 2024, 10(8), 533; https://doi.org/10.3390/gels10080533 - 13 Aug 2024
Abstract
In this study, novel functional ZEO-complex gels were prepared using sodium alginate, inulin, grape seed extract (GSE), and Zanthoxylum bungeanum essential oil (ZEO) as the primary raw materials. The effect of the addition of inulin, GSE, and ZEO on water vapor permeability (WVP),
[...] Read more.
In this study, novel functional ZEO-complex gels were prepared using sodium alginate, inulin, grape seed extract (GSE), and Zanthoxylum bungeanum essential oil (ZEO) as the primary raw materials. The effect of the addition of inulin, GSE, and ZEO on water vapor permeability (WVP), tensile strength (TS), and elongation at break (EAB) of ZEO-complex polysaccharide gels was investigated. A comprehensive score (Y) for evaluating the characteristics of ZEO-complex polysaccharide gels was established by principal component analysis. MATLAB analysis and box-Behnken design describe each factor’s four-dimensional and three-dimensional interactions. It was found that Y could reach the maximum value when the ZEO addition was at a moderate level (C = 2%). The optimum preparation process of ZEO-complex polysaccharide gels was as follows: the addition of inulin was at 0.84%, the addition of GSE was at 0.04%, and the addition of ZEO was at 2.0785%; in this way, the Y of ZEO-complex polysaccharide gels reached the maximum (0.82276). Optical scanning and X-ray diffraction tests confirmed that the prepared ZEO-complex gels have a smooth and continuous microstructure, good water insulation, and mechanical properties. The storage test results show that ZEO-complex polysaccharide gels could play a significant role in the storage and fresh-keeping of grass carp, and the physicochemical properties of complex polysaccharide gels were improved by adding ZEO. In addition, according to the correlation of fish index changes during storage, adding ZEO in complex polysaccharide gels was closely correlated with the changes in fish TBARS and TVB-N oxidation decay indices. In conclusion, the ZEO-complex polysaccharide gels prepared in this study had excellent water insulation, mechanical properties, and outstanding fresh-keeping effects on grass carp.
Full article
(This article belongs to the Section Gel Chemistry and Physics)
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Open AccessArticle
Preparation and Characterization of Responsive Cellulose-Based Gel Microspheres for Enhanced Oil Recovery
by
Peng Yin, Fang Shi, Mingjian Luo, Jingchun Wu, Bo Zhao, Chunlong Zhang, Yi Shen and Yanbing Chen
Gels 2024, 10(8), 532; https://doi.org/10.3390/gels10080532 - 13 Aug 2024
Abstract
As an important means to enhance oil recovery, ternary composite flooding (ASP flooding for short) technology has achieved remarkable results in Daqing Oilfield. Alkalis, surfactants and polymers are mixed in specific proportions and injected into the reservoir to give full play to the
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As an important means to enhance oil recovery, ternary composite flooding (ASP flooding for short) technology has achieved remarkable results in Daqing Oilfield. Alkalis, surfactants and polymers are mixed in specific proportions and injected into the reservoir to give full play to the synergistic effect of each component, which can effectively enhance the fluidity of crude oil and greatly improve the oil recovery. At present, the technology for further improving oil recovery after ternary composite flooding is not mature and belongs to the stage of technical exploration. The presence of alkaline substances significantly alters the reservoir’s physical properties and causes considerable corrosion to the equipment used in its development. This is detrimental to both the environment and production. Therefore, it is necessary to develop green displacement control agents. In the reservoir environment post-ASP flooding, 2-(methylamino)ethyl methacrylate and glycidyl methacrylate were chosen as monomers to synthesize a polymer responsive to alkali, and then grafted with cellulose nanocrystals to form microspheres of alkali-resistant swelling hydrogel. Cellulose nanocrystals (CNCs) modified with functional groups and other materials were utilized to fabricate hydrogel microspheres. The product’s structure was characterized and validated using Fourier transform infrared spectroscopy and X-ray diffraction. The infrared spectrum revealed characteristic absorption peaks of CNCs at 1165 cm−1, 1577 cm−1, 1746 cm−1, and 3342 cm−1. The diffraction spectrum corroborated the findings of the infrared analysis, indicating that the functional modification occurred on the CNC surface. After evaluating the swelling and erosion resistance of the hydrogel microspheres under various alkaline conditions, the optimal particle size for compatibility with the target reservoir was determined to be 6 μm. The potential of cellulose-based gel microspheres to enhance oil recovery was assessed through the evaluation of Zeta potential and laboratory physical simulations of oil displacement. The study revealed that the absolute value of the Zeta potential for gel microspheres exceeds 30 in an alkaline environment with pH values ranging from 7 to 14, exhibiting a phenomenon where stronger alkalinity correlates with a greater absolute value of Zeta potential. The dispersion stability spans from good to excellent. The laboratory oil displacement simulation experiment was conducted using a cellulose-based gel microsphere system following weak alkali ASP flooding within the pH value range from 7 to 10. The experimental interventions yielded recovery rates of 2.98%, 3.20%, 3.31%, and 3.38%, respectively. The study indicates that cellulose-based gel microspheres exhibit good adaptability in alkaline reservoirs. This research offers a theoretical foundation and experimental approaches to enhance oil recovery techniques post-ASP flooding.
Full article
(This article belongs to the Special Issue Polymer Gels for the Oil and Gas Industry)
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Open AccessArticle
Elastin-Derived Peptide-Based Hydrogels as a Potential Drug Delivery System
by
Othman Al Musaimi, Keng Wooi Ng, Varshitha Gavva, Oscar M. Mercado-Valenzo, Hajira Banu Haroon and Daryl R. Williams
Gels 2024, 10(8), 531; https://doi.org/10.3390/gels10080531 - 12 Aug 2024
Abstract
A peptide-based hydrogel sequence was computationally predicted from the Ala-rich cross-linked domains of elastin. Three candidate peptides were subsequently synthesised and characterised as potential drug delivery vehicles. The elastin-derived peptides are Fmoc-FFAAAAKAA-NH2, Fmoc-FFAAAKAA-NH2, and Fmoc-FFAAAKAAA-NH2. All three
[...] Read more.
A peptide-based hydrogel sequence was computationally predicted from the Ala-rich cross-linked domains of elastin. Three candidate peptides were subsequently synthesised and characterised as potential drug delivery vehicles. The elastin-derived peptides are Fmoc-FFAAAAKAA-NH2, Fmoc-FFAAAKAA-NH2, and Fmoc-FFAAAKAAA-NH2. All three peptide sequences were able to self-assemble into nanofibers. However, only the first two could form hydrogels, which are preferred as delivery systems compared to solutions. Both of these peptides also exhibited favourable nanofiber lengths of at least 1.86 and 4.57 µm, respectively, which are beneficial for the successful delivery and stability of drugs. The shorter fibre lengths of the third peptide (maximum 0.649 µm) could have inhibited their self-assembly into the three-dimensional networks crucial to hydrogel formation.
Full article
(This article belongs to the Special Issue Recent Advances in Gels Engineering for Drug Delivery (2nd Edition))
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Open AccessArticle
The Impact of Gel Parameters on the Dispersal and Fragmentation of Hyaluronic Acid Gel Fillers within an Artificial Model of Arterial Embolism
by
Danny J. Soares and Alec D. McCarthy
Gels 2024, 10(8), 530; https://doi.org/10.3390/gels10080530 - 12 Aug 2024
Abstract
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Accidental arterial embolization of hyaluronic acid (HA) fillers can lead to severe complications, including skin ischemia, blindness, and stroke. Currently, the intra-arterial dispersal and fragmentation behavior of HA gels is unknown but critical to our understanding of the pathomechanism of these injuries. This
[...] Read more.
Accidental arterial embolization of hyaluronic acid (HA) fillers can lead to severe complications, including skin ischemia, blindness, and stroke. Currently, the intra-arterial dispersal and fragmentation behavior of HA gels is unknown but critical to our understanding of the pathomechanism of these injuries. This work introduces the Pulsatile Unit for the Laboratory Simulation of Arterio-embolic Restrictions (PULSAR) and evaluates the intravascular behavior of different HA gels. The fragmentation and dispersal behaviors of four HA gels with distinct rheological properties were evaluated via high-resolution videography and ImageJ particle size and morphology analysis. The gels’ elastic modulus (G′), loss modulus (G″), tan(δ), and HA concentration were subsequently correlated with their intra-arterial behaviors. This study effectively confirms the extensive fragmentation of HA gels upon arterial inoculation, with particle sizes ranging from <50 µm to >1 mm. Gel particle size and morphology correlated most significantly with tan(δ). Conversely, arterial flow rates did not significantly influence gel fragmentation behavior, though the probability of proximal, macrovascular obstruction was affected. Overall, this study validates the PULSAR model for simulation of arterial dynamics and the testing of intravascular filler kinematics. The findings demonstrate the ability of gels to microfragment and disseminate distally, as well as induce partial proximal occlusion depending on gel rheology and arterial flow parameters.
Full article
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Open AccessArticle
Moisture Sorption Isotherms of Polydextrose and Its Gelling Efficiency in Inhibiting the Retrogradation of Rice Starch
by
Chang Liu, Xiaoyu Li, Hongdong Song and Xingjun Li
Gels 2024, 10(8), 529; https://doi.org/10.3390/gels10080529 - 12 Aug 2024
Abstract
As an anti-staling agent in bread, the desorption isotherm of polydextrose has not been studied due to a very long equilibrium time. The adsorption and desorption isotherms of five Chinese polydextrose products were measured in the range of 0.1–0.9 aw and 20–35
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As an anti-staling agent in bread, the desorption isotherm of polydextrose has not been studied due to a very long equilibrium time. The adsorption and desorption isotherms of five Chinese polydextrose products were measured in the range of 0.1–0.9 aw and 20–35 °C by a dynamic moisture sorption analyzer. The results show that the shape of adsorption and desorption isotherms was similar to that of amorphous lactose. In the range of 0.1–0.8 aw, the hysteresis between desorption and adsorption of polydextrose was significant. The sorption isotherms of polydextrose can be fitted by seven commonly used models, and our developed seven-parameter polynomial, the adsorption equations of generalized D’Arcy and Watt (GDW) and Ferro-Fontan, and desorption equations of polynomial and Peleg, performed well in the range of 0.1–0.9 aw. The hysteresis curves of polydextrose at four temperatures quickly decreased with aw increase at aw ˂ 0.5, andthereafter slowly decreased when aw ≥ 0.5. The polynomial fitting hysteresis curves of polydextrose were divided into three regions: ˂0.2, 0.2–0.7, and 0.71–0.9 aw. The addition of 0–10% polydextrose to rice starch decreased the surface adsorption and bulk absorption during the adsorption and desorption of rice starch, while it increased the water adsorption value at aw ≥ 0.7 due to polydextrose dissolution. DSC analysis showed that polydextrose as a gelling agent inhibited the retrogradation of rice starch, which could be used to maintain the quality of cooked rice.
Full article
(This article belongs to the Special Issue Recent Advance in Food Gels (2nd Edition))
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Open AccessArticle
Screening of Optimal Konjac Glucomannan–Protein Composite Gel Formulations to Mimic the Texture and Appearance of Tripe
by
Qiang Zou, Yudie Liu, Linghui Luo, Yuyou Chen, Yuhan Zheng, Guilian Ran and Dayu Liu
Gels 2024, 10(8), 528; https://doi.org/10.3390/gels10080528 - 12 Aug 2024
Abstract
This study aimed to develop a product that closely replicates the texture and appearance of tripe. The effect of three different proteins (soy protein isolate (SPI), pea protein isolate (PPI), and whey protein isolate (WPI)) at different protein levels and processing conditions (heating
[...] Read more.
This study aimed to develop a product that closely replicates the texture and appearance of tripe. The effect of three different proteins (soy protein isolate (SPI), pea protein isolate (PPI), and whey protein isolate (WPI)) at different protein levels and processing conditions (heating (90 °C, 1 h) followed by cooling (4 °C, 12 h) and heating (90 °C, 1h) followed by freezing (−18 °C, 12 h)) of konjac glucomannan (KGM) was analyzed. The optimal formulations for simulating tripe were screened by examining their similarity to real tripe in terms of texture, color, and sensory experience. The screened formulations were also subjected to a preliminary mechanistic investigation. The results show that all three proteins improved the gel’s textural properties to varying degrees. At the same concentration, the hardness and chewiness of the KGM/WPI composite gel were significantly higher than those of the other two KGM/protein composite gels, among which the composite gel obtained by adding 8% WPI and 5% KGM heating-frozen (FWK4) had the greatest hardness and chewiness of 4338.07 g and 2313.76, respectively, and the springiness differences in all of the composite gels were small. In addition, the addition of protein increased the whiteness of the hybrid gels, with WPI having the most significant effect on the whiteness of the composite gels (whiteness increased from 30.25 to 62.80 as the concentration of WPI increased from 0 to 10%). Freezing increased composite gel hardness and chewiness, but reduced gel springiness and whiteness. Cluster analysis showed that the composite gel obtained by heating–cooling 8% WPI and 5% KGM (WK4) was very similar to the real tripe in terms of chewiness and whiteness, and WK4 had the highest sensory scores for color, tissue morphology, tactile sensation, taste, and odor. The acceptability score in terms of tissue morphology reached 4.3. Meanwhile, the characterization results of WK4 indicate the presence of large junction areas in the gel network. Fourier transform infrared spectroscopy (FTIR) analysis, X-ray diffraction, and intermolecular force contributions indicated that the incorporation of WPI promoted integral interactions, and that hydrophobic interactions and disulfide bonding played a key role in the WK4 composite gel system. Moreover, scanning electron microscopy (SEM) also showed that the combination of WPI and konjac glucan resulted in a more compact gel structure. This study is informative for the development of the field of bionic tripe processing.
Full article
(This article belongs to the Special Issue Recent Advance in Food Gels (2nd Edition))
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Open AccessArticle
Enhancement of Mechanical Properties of Benign Polyvinyl Alcohol/Agar Hydrogel by Crosslinking Tannic Acid and Applying Multiple Freeze/Thaw Cycles
by
Moustapha Mohamed Mahamoud, Tadesse Mekonnin Ketema, Yutaka Kuwahara and Makoto Takafuji
Gels 2024, 10(8), 527; https://doi.org/10.3390/gels10080527 - 12 Aug 2024
Abstract
Hydrogels composed of natural and synthetic polymers have considerable potential for use in diverse areas such as biomedical applications and water purification. This is primarily because of their biocompatibility, biodegradability, and low toxicity. The widespread usage of composite hydrogels is hindered by a
[...] Read more.
Hydrogels composed of natural and synthetic polymers have considerable potential for use in diverse areas such as biomedical applications and water purification. This is primarily because of their biocompatibility, biodegradability, and low toxicity. The widespread usage of composite hydrogels is hindered by a lack of simultaneous properties, such as high strength and low swelling rate. Herein, we report the preparation of novel hydrogels composed of polyvinyl alcohol (PVA)–intercalated agar polymer networks physically crosslinked with tannic acid. The hydrogel was subjected to multiple freeze/thaw (F/T) cycles (1, 3, and 5), and it was found to exhibit the highest strength after 5 F/T cycles. After 1 F/T cycle, the tensile strength of the composite hydrogel reached 1.56 MPa with a 1.0 wt% crosslinker, whereas after 5 F/T cycles, it increased to 3.77 MPa with a reduced amount (0.75 wt%) of the crosslinker. In addition, the swelling ability decreased upon increasing the crosslinker content and number of F/T cycles. Furthermore, the hydrogel demonstrated excellent water retention and a strong ability to adhere to different substrates. We have successfully implemented an innovative approach to improve the mechanical properties of PVA-based hydrogels by combining the use of tannic acid as a cross-linking agent and multiple F/T cycles. The developed hydrogels are expected to facilitate new developments in hydrogel technology, thus impacting diverse fields such as biomedical (wound dressing and artificial cartilage).
Full article
(This article belongs to the Special Issue Global Excellence in Bioactive Gels)
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Open AccessArticle
Radially and Axially Oriented Ammonium Alginate Aerogels Modified with Clay/Tannic Acid and Crosslinked with Glutaraldehyde
by
Lucía G. De la Cruz, Tobias Abt, Noel León and Miguel Sánchez-Soto
Gels 2024, 10(8), 526; https://doi.org/10.3390/gels10080526 - 10 Aug 2024
Abstract
Lightweight materials that combine high mechanical strength, insulation, and fire resistance are of great interest to many industries. This work explores the properties of environmentally friendly alginate aerogel composites as potential sustainable alternatives to petroleum-based materials. This study analyzes the effects of two
[...] Read more.
Lightweight materials that combine high mechanical strength, insulation, and fire resistance are of great interest to many industries. This work explores the properties of environmentally friendly alginate aerogel composites as potential sustainable alternatives to petroleum-based materials. This study analyzes the effects of two additives (tannic acid and montmorillonite clay), the orientation that results during casting, and the crosslinking of the biopolymer with glutaraldehyde on the properties of the aerogel composites. The prepared aerogels exhibited high porosities between 90% and 97% and densities in the range of 0.059–0.191 g/cm3. Crosslinking increased the density and resulted in excellent performance under loading conditions. In combination with axial orientation, Young’s modulus and yield strength reached values as high as 305 MPa·cm3/g and 7 MPa·cm3/g, respectively. Moreover, the alginate-based aerogels exhibited very low thermal conductivities, ranging from 0.038 W/m·K to 0.053 W/m·K. Compared to pristine alginate, the aerogel composites’ thermal degradation rate decreased substantially, enhancing thermal stability. Although glutaraldehyde promoted combustion, the non-crosslinked aerogel composites demonstrated high fire resistance. No flame was observed in these samples under cone calorimeter radiation, and a minuscule peak of heat release of 21 kW/m2 was emitted as a result of their highly efficient graphitization and fire suppression. The combination of properties of these bio-based aerogels demonstrates their potential as substituents for their fossil-based counterparts.
Full article
(This article belongs to the Special Issue Recent Progress and Development of Advanced Aerogels: Latest Processing Methods, Improved Properties and Application)
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Open AccessReview
Plant-Based Nanovesicular Gel Formulations Applied to Skin for Ameliorating the Anti-Inflammatory Efficiency
by
Hanan Abdelmawgoud Atia, Mona M. Shahien, Somaia Ibrahim, Enas Haridy Ahmed, Hemat A. Elariny and Marwa H. Abdallah
Gels 2024, 10(8), 525; https://doi.org/10.3390/gels10080525 - 10 Aug 2024
Abstract
Inflammation is a vascular response that occurs when the immune system responds to a range of stimuli including viruses, allergens, damaged cells, and toxic substances. Inflammation is accompanied by redness, heat, swelling, discomfort, and loss of function. Natural products have been shown to
[...] Read more.
Inflammation is a vascular response that occurs when the immune system responds to a range of stimuli including viruses, allergens, damaged cells, and toxic substances. Inflammation is accompanied by redness, heat, swelling, discomfort, and loss of function. Natural products have been shown to have considerable therapeutic benefits, and they are increasingly being regarded as feasible alternatives for clinical preventative, diagnostic, and treatment techniques. Natural products, in contrast to developed medications, not only contain a wide variety of structures, they also display a wide range of biological activities against a variety of disease states and molecular targets. This makes natural products appealing for development in the field of medicine. In spite of the progress that has been made in the application of natural products for clinical reasons, there are still factors that prevent them from reaching their full potential, including poor solubility and stability, as well limited efficacy and bioavailability. In order to address these problems, transdermal nanovesicular gel systems have emerged as a viable way to overcome the hurdles that are encountered in the therapeutic use of natural products. These systems have a number of significant advantages, including the ability to provide sustained and controlled release, a large specific surface area, improved solubility, stability, increased targeting capabilities and therapeutic effectiveness. Further data confirming the efficacy and safety of nanovesicles–gel systems in delivering natural products in preclinical models has been supplied by extensive investigations conducted both in vitro and in vivo. This study provides a summary of previous research as well as the development of novel nanovesicular gel formulations and their application through the skin with a particular emphasis on natural products used for treatment of inflammation.
Full article
(This article belongs to the Special Issue Hydrogels for Therapeutic Delivery: Current Developments and Future Directions)
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Open AccessArticle
Viscoelastic Reversibility of Carrageenan Hydrogels under Large Amplitude Oscillatory Shear: Hybrid Carrageenans versus Blends
by
Izabel Cristina Freitas Moraes and Loic Hilliou
Gels 2024, 10(8), 524; https://doi.org/10.3390/gels10080524 - 9 Aug 2024
Abstract
The viscoelastic response of carrageenan hydrogels to large amplitude oscillatory shear (LAOS) has not received much attention in the literature in spite of its relevance in industrial application. A set of hybrid carrageenans with differing chemical compositions are gelled in the presence of
[...] Read more.
The viscoelastic response of carrageenan hydrogels to large amplitude oscillatory shear (LAOS) has not received much attention in the literature in spite of its relevance in industrial application. A set of hybrid carrageenans with differing chemical compositions are gelled in the presence of KCl or NaCl, and their nonlinear viscoelastic responses are systematically compared with mixtures of kappa- and iota-carrageenans of equivalent kappa-carrageenan contents. Two categories of LAOS response are identified: strain softening and strain hardening gels. Strain softening gels show LAOS non-reversibility: when entering the nonlinear viscoelastic regime, the shear storage modulus G′ decreases with increasing strain, and never recovers its linear value G0 after successive LAOS sweeps. In contrast to this, strain hardening carrageenan gels show a certain amount of LAOS reversibility: when entering the nonlinear regime, G′ increases with strain and shows a maximum at strain γH. For strains applied below γH, G0 shows good reversibility and the strain hardening behavior is maintained. For strains larger than γH, G0 decreases significantly indicating an irreversible structural change in the elastic network. Strain hardening and elastic recovery after LAOS prevail for hybrid carrageenan and iota-carrageenan gels, but are only achieved when blends are gelled in NaCl, suggesting a phase separated structure with a certain degree of co-aggregated interface for mixed gels.
Full article
(This article belongs to the Special Issue Gel-Related Papers from the 9th Asian Conference on Colloid and Interface Science 2023 (ACCIS 2023))
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Open AccessArticle
Tailoring the Structure and Physico-Chemical Features of Cellulose-Based Hydrogels Using Multi-Epoxy Crosslinking Agents
by
Raluca Nicu, Gabriela Lisa, Raluca Nicoleta Darie-Nita, Mihaela Iuliana Avadanei, Alexandra Bargan, Daniela Rusu and Diana Elena Ciolacu
Gels 2024, 10(8), 523; https://doi.org/10.3390/gels10080523 - 9 Aug 2024
Abstract
Hydrogel features can be designed and optimized using different crosslinking agents to meet specific requirements. In this regard, the present work investigates the physico-chemical features of cellulose-based hydrogels, designed by using different epoxy crosslinkers from the same glycidyl family, namely epichlorohydrin (ECH), 1,4-butanediol
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Hydrogel features can be designed and optimized using different crosslinking agents to meet specific requirements. In this regard, the present work investigates the physico-chemical features of cellulose-based hydrogels, designed by using different epoxy crosslinkers from the same glycidyl family, namely epichlorohydrin (ECH), 1,4-butanediol diglycidyl ether (BDDE), and trimethylolpropane triglycidyl ether (TMPTGE). The effect of the crosslinker’s structure (from simple to branched) and functionality (mono-, bi- and tri-epoxy groups) on the hydrogels’ features was studied. The performances of the hydrogels were investigated through the gel fraction, as well as by ATR-FTIR, DVS, SEM, DSC, and TG analyses. Also, the swelling and rheological behaviors of the hydrogels were examined. The advantages and limitations of each approach were discussed and a strong correlation between the crosslinker structure and the hydrogel properties was established. The formation of new ether bonds was evidenced by ATR-FTIR spectroscopy. It was emphasized that the pore size is directly influenced by the crosslinker type, namely, it decreases with the increasing number of epoxy groups from the crosslinker molecule, i.e., from 46 ± 11.1 µm (hydrogel CE, with ECH) to 12.3 ± 2.5 µm (hydrogel CB, with BDDE) and 6.7 ± 1.5 µm (hydrogel CT, with TMPTGE). The rheological behavior is consistent with the swelling data and hydrogel morphology, such as CE with the highest Qmax and the largest pore size being relatively more elastic than CB and CT. Instead, the denser matrices obtained by using crosslinkers with more complex structures have better thermal stability. The experimental results highlight the possibility of using a specific crosslinking agent, with a defined structure and functionality, in order to establish the main characteristics of hydrogels and, implicitly, to design them for a certain field of application.
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(This article belongs to the Special Issue Polysaccharide: Gelation Arts)
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Open AccessArticle
Utilization of Infrared Drying as Alternative to Spray- and Freeze-Drying for Low Energy Consumption in the Production of Powdered Gelatin
by
Ümran Cansu
Gels 2024, 10(8), 522; https://doi.org/10.3390/gels10080522 - 9 Aug 2024
Abstract
This study evaluated possible utilization of infrared drying (ID) as an alternative to spray- (SD) and freeze-drying (FD) for fish skin-derived gelatins. Physical, functional, thermal, and spectroscopic analyses were conducted for characterization of the resulting gelatin powders. Energy consumption for the applied drying
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This study evaluated possible utilization of infrared drying (ID) as an alternative to spray- (SD) and freeze-drying (FD) for fish skin-derived gelatins. Physical, functional, thermal, and spectroscopic analyses were conducted for characterization of the resulting gelatin powders. Energy consumption for the applied drying methods were 3.41, 8.46 and 25.33 kWh/kg for ID, SD and FD respectively, indicating that ID had the lowest energy consumption among the studied methods. Gel strength, on the other hand, was lower (398.4 g) in infrared-dried gelatin (ID-FG) compared to that (454.9 g) of freeze-dried gelatin (FD-FG) and that (472.7 g) of spray-dried gelatin (SD-FG). TGA curves indicated that ID-FG showed more resilience to thermal degradation. SDS-PAGE and UV-Vis spectra indicated that slight degradation was observed in the β-configuration of ID-FG. ID-FG and SD-FG gelatins had the highest water holding capacity (WHC), protein solubility and transparency values compared to that of FD-FG. Morphological structures of the samples were quite different as shown by SEM visuals. Ultimately, the findings showed that infrared drying may be a promising alternative for gelatin processing, maintaining product quality and supporting sustainable practices in food and other industries.
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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
Comparative Study of TPGS and Soluplus Polymeric Micelles Embedded in Poloxamer 407 In Situ Gels for Intranasal Administration
by
Bence Sipos, Frézia Földes, Mária Budai-Szűcs, Gábor Katona and Ildikó Csóka
Gels 2024, 10(8), 521; https://doi.org/10.3390/gels10080521 - 9 Aug 2024
Abstract
This study aims to highlight the importance of choosing the appropriate co-polymer or co-polymer mixed combinations in order to design value-added nasal dosage forms. Local therapy of upper respiratory tract-related infections, such as nasal rhinosinusitis is of paramount importance, thus advanced local therapeutic
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This study aims to highlight the importance of choosing the appropriate co-polymer or co-polymer mixed combinations in order to design value-added nasal dosage forms. Local therapy of upper respiratory tract-related infections, such as nasal rhinosinusitis is of paramount importance, thus advanced local therapeutic options are required. Dexamethasone was encapsulated into three different polymeric micelle formulations: Soluplus or TPGS-only and their mixed combinations. Dynamic light scattering measurements proved that the particles have a micelle size less than 100 nm in monodisperse distribution, with high encapsulation efficiency above 80% and an at least 7-fold water solubility increase. Tobramycin, as an antimicrobial agent, was co-formulated into the in situ gelling systems which were optimized based on gelation time and gelation temperature. The sol–gel transition takes place between 32–35 °C, which is optimally below the temperature of the nasal cavity in a quick manner below 5 min, a suitable strategic criterion against the mucociliary clearance. In vitro drug release and permeability studies confirmed a rapid kinetics in the case of the encapsulated dexamethasone accompanied with a sustained release of tobramycin, as the hydrophilic drug.
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(This article belongs to the Section Gel Analysis and Characterization)
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Open AccessArticle
Preparation and Adsorption Photocatalytic Properties of PVA/TiO2 Colloidal Photonic Crystal Films
by
Zhangyi Qian, Menghan Wang, Junling Li, Zhaoran Chu, Wenwei Tang and Cheng Chen
Gels 2024, 10(8), 520; https://doi.org/10.3390/gels10080520 - 7 Aug 2024
Abstract
Polyvinyl alcohol (PVA)/TiO2/colloidal photonic crystal (CPC) films with photocatalytic properties are presented, where TiO2 nanoparticles were introduced into the PVA gel network. Such PVA/TiO2/CPC films possess three-dimensional periodic structures that are supported with a PVA/TiO2 composite gel.
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Polyvinyl alcohol (PVA)/TiO2/colloidal photonic crystal (CPC) films with photocatalytic properties are presented, where TiO2 nanoparticles were introduced into the PVA gel network. Such PVA/TiO2/CPC films possess three-dimensional periodic structures that are supported with a PVA/TiO2 composite gel. The unique structural color of CPCs can indicate the process of material preparation, adsorption, and desorption. The shift of diffraction peaks of CPCs can be more accurately determined using fiber-optic spectroscopy. The effect of the PVA/TiO2/CPC catalyst films showed better properties as the degradation of methylene blue (MB) by the PVA/TiO2/CPC film catalyst in 4 h was 77~90%, while the degradation of MB by the PVA/TiO2 film was 33% in 4 h, indicating that the photonic crystal structure was 2.3~2.7 times more effective than that of the bulk structure.
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(This article belongs to the Special Issue Application of Smart Gel Material in Flexible and Wearable Electronics)
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Open AccessArticle
Synthesis of Flexible Polyamide Aerogels Cross-Linked with a Tri-Isocyanate
by
Daniel A. Scheiman, Haiquan Guo, Katherine J. Oosterbaan, Linda McCorkle and Baochau N. Nguyen
Gels 2024, 10(8), 519; https://doi.org/10.3390/gels10080519 - 7 Aug 2024
Abstract
A new series of flexible polyamide (PA) aerogels was synthesized using terephthaloyl chloride (TPC), 2,2′-dimethylbenzidine (DMBZ) and cross-linked with an inexpensive, commercially available tri-isocyanate (Desmodur N3300A) at polymer concentrations of 6–8 wt.% total solids and repeating units, n, from 30 to 60.
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A new series of flexible polyamide (PA) aerogels was synthesized using terephthaloyl chloride (TPC), 2,2′-dimethylbenzidine (DMBZ) and cross-linked with an inexpensive, commercially available tri-isocyanate (Desmodur N3300A) at polymer concentrations of 6–8 wt.% total solids and repeating units, n, from 30 to 60. The cross-linked DMBZ-based polyamide aerogels obtained, after supercritically drying using liquid CO2, had shrinkages of 19–27% with densities ranging from 0.12 g/cm3 to 0.22 g/cm3, porosity and surface areas up to 91% and 309 m2/g, respectively, and modulus values ranging from 20.6 to 109 MPa. Evidence suggests that a higher flexibility could be achieved using DMBZ in the polyamide backbone with N3300A as a cross-linker, when compared to previously reported TPC-mPDA-BTC PA aerogels, N3300A-polyimide aerogels, and N3300-reinforced silica aerogels.
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(This article belongs to the Special Issue Aerogels—Preparation and Properties)
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Open AccessArticle
Patterned PVA Hydrogels with 3D Petri Dish® Micro-Molds of Varying Topography for Spheroid Formation of HeLa Cancer Cells: In Vitro Assessment
by
Maira Moreno Valtierra, Adriana Urue Corral, Jorge Armando Jiménez-Avalos, Erika Barbosa Avalos, Judith Dávila-Rodríguez, Norma Morales Hernández, Mauricio Comas-García, Guillermo Toriz González, Antonio Oceguera-Villanueva, José Alfonso Cruz-Ramos, Rodolfo Hernández Gutiérrez, Moisés Martínez Velázquez and Zaira Yunuen García Carvajal
Gels 2024, 10(8), 518; https://doi.org/10.3390/gels10080518 - 6 Aug 2024
Abstract
Cell spheroids are an important three-dimensional (3D) model for in vitro testing and are gaining interest for their use in clinical applications. More natural 3D cell culture environments that support cell–cell interactions have been created for cancer drug discovery and therapy applications, such
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Cell spheroids are an important three-dimensional (3D) model for in vitro testing and are gaining interest for their use in clinical applications. More natural 3D cell culture environments that support cell–cell interactions have been created for cancer drug discovery and therapy applications, such as the scaffold-free 3D Petri Dish® technology. This technology uses reusable and autoclavable silicone micro-molds with different topographies, and it conventionally uses gelled agarose for hydrogel formation to preserve the topography of the selected micro-mold. The present study investigated the feasibility of using a patterned Poly(vinyl alcohol) hydrogel using the circular topography 12–81 (9 × 9 wells) micro-mold to form HeLa cancer cell spheroids and compare them with the formed spheroids using agarose hydrogels. PVA hydrogels showed a slightly softer, springier, and stickier texture than agarose hydrogels. After preparation, Fourier transform infrared (FTIR) spectra showed chemical interactions through hydrogen bonding in the PVA and agarose hydrogels. Both types of hydrogels favor the formation of large HeLa spheroids with an average diameter of around 700–800 µm after 72 h. However, the PVA spheroids are more compact than those from agarose, suggesting a potential influence of micro-mold surface chemistry on cell behavior and spheroid formation. This was additionally confirmed by evaluating the spheroid size, morphology, integrity, as well as E-cadherin and Ki67 expression. The results suggest that PVA promotes stronger cell-to-cell interactions in the spheroids. Even the integrity of PVA spheroids was maintained after exposure to the drug cisplatin. In conclusion, the patterned PVA hydrogels were successfully prepared using the 3D Petri Dish® micro-molds, and they could be used as suitable platforms for studying cell–cell interactions in cancer drug therapy.
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(This article belongs to the Special Issue Advances in Hydrogels and Hydrogel-Based Composites)
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Open AccessReview
A Review on Traditional and Artificial Intelligence-Based Preservation Techniques for Oil Painting Artworks
by
Salman Khalid, Muhammad Muzammil Azad, Heung Soo Kim, Yanggi Yoon, Hanhyoung Lee, Kwang-Soon Choi and Yoonmo Yang
Gels 2024, 10(8), 517; https://doi.org/10.3390/gels10080517 - 6 Aug 2024
Abstract
Oil paintings represent significant cultural heritage, as they embody human creativity and historical narratives. The preservation of these invaluable artifacts requires effective maintenance practices to ensure their longevity and integrity. Despite their inherent durability, oil paintings are susceptible to mechanical damage and chemical
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Oil paintings represent significant cultural heritage, as they embody human creativity and historical narratives. The preservation of these invaluable artifacts requires effective maintenance practices to ensure their longevity and integrity. Despite their inherent durability, oil paintings are susceptible to mechanical damage and chemical deterioration, necessitating rigorous conservation efforts. Traditional preservation techniques that have been developed over centuries involve surface treatment, structural stabilization, and gel-based cleaning to maintain both the integrity and aesthetic appeal of these artworks. Recent advances in artificial intelligence (AI)-powered predictive maintenance techniques offer innovative solutions to predict and prevent deterioration. By integrating image analysis and environmental monitoring, AI-based models provide valuable insights into painting preservation. This review comprehensively analyzes traditional and AI-based techniques for oil painting maintenance, highlighting the importance of adopting innovative approaches. By integrating traditional expertise with AI technology, conservators can enhance their capacity to maintain and preserve these cultural treasures for future generations.
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(This article belongs to the Special Issue Gel Materials for Heritage Conservation)
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