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
The Preparation and Evaluation of a Hydrochloride Hydrogel Patch with an Iontophoresis-Assisted Release of Terbinafine for Transdermal Delivery
Gels 2024, 10(7), 456; https://doi.org/10.3390/gels10070456 (registering DOI) - 12 Jul 2024
Abstract
Background: Terbinafine hydrochloride (TEB) is a broad-spectrum antifungal medication commonly used to treat fungal infections of the skin. This study designed a hydrogel patch assisted by an iontophoresis system to enhance the transdermal permeability of TEB, enabling deeper penetration into the skin layers.
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Background: Terbinafine hydrochloride (TEB) is a broad-spectrum antifungal medication commonly used to treat fungal infections of the skin. This study designed a hydrogel patch assisted by an iontophoresis system to enhance the transdermal permeability of TEB, enabling deeper penetration into the skin layers. Methods: The influences of current intensity, pH levels, and drug concentration on the TEB hydrogel patch’s permeability were explored using an adaptive ion electroosmosis system. The pharmacokinetic profile, facilitated by iontophoresis for transdermal permeation, was analyzed through the application of microdialysis technology. Scanning electron microscopy and transmission electron microscopy were employed to assess the impact of ion electroosmotic systems on skin integrity. Results: The cumulative drug accumulation within 8 h of the TEB hydrogel patches, assisted by iontophoresis, was 2.9 and 7.9 times higher than without iontophoresis assistance and TEB cream in the control group, respectively. TEB hydrogel patches assisted by iontophoresis can significantly increase the permeability of TEB, and the AUC(0–8 h) was 3.4 and 5.4 times higher, while the Cmax was 4.2 and 7.3 times higher than the TEB hydrogel patches without iontophoresis, respectively. This system has no significant impact on deep-layer cells. Conclusions: This system may offer a safe and effective clinical strategy for the local treatment of deep antifungal infections.
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(This article belongs to the Special Issue Novel Functional Gels for Biomedical Applications)
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Multi-Technique Assessment of Chelators-Loaded PVA-Borax Gel-like Systems Performance in Cleaning of Stone Contaminated with Copper Corrosion Products
by
Laura Giuliani, Chiara Genova, Valeria Stagno, Luca Paoletti, Andrea Louise Matulac, Alessandro Ciccola, Melania Di Fazio, Silvia Capuani and Gabriele Favero
Gels 2024, 10(7), 455; https://doi.org/10.3390/gels10070455 - 11 Jul 2024
Abstract
Currently, one of the most important challenges for the conservation of stone artworks is the removal of metal corrosion products on their surfaces. Traditional cleaning methods, which typically involve the application of aqueous solutions containing chelating agents capable of complexing these metal ions,
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Currently, one of the most important challenges for the conservation of stone artworks is the removal of metal corrosion products on their surfaces. Traditional cleaning methods, which typically involve the application of aqueous solutions containing chelating agents capable of complexing these metal ions, have shown some weaknesses. These weaknesses become apparent when such methods are applied to statues and other vertical surfaces or when aiming to limit the cleaning process to a specific area with controlled application times. Furthermore, the porosity of the stone surface plays a role concerning the cleaning efficiency. To address these issues, chelating agents can be incorporated into gel-like materials. This study is a proof of concept to evaluate the cleaning efficacy of various gel formulations composed of polyvinyl alcohol (PVA), borax (B), and agarose (AG), loaded with two chelators: ethylenediaminetetraacetic acid (EDTA) and potassium sodium tartrate (PST or Rochelle salt). Three types of carbonate stones (travertine, Lecce stone, and Carrara marble) characterized by different porosities were artificially stained with copper sulphates and treated with the different PVA-B-AG formulations. The effectiveness of the treatment was directly monitored on the stones using a multi-technique approach that included scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and non-invasive portable nuclear magnetic resonance (NMR). Additionally, the rheological properties of the gels were investigated, and the Fourier transform infrared attenuated total reflection spectroscopy (FTIR ATR) was used to analyse the chemical structure of the gel before and after treatment, aiming to understand the changes induced by the cleaning process.
Full article
(This article belongs to the Special Issue Physical and Mechanical Properties of Polymer Gels (2nd Edition))
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Comparative Analysis of Gracilaria chouae Polysaccharides Derived from Different Geographical Regions: Focusing on Their Chemical Composition, Rheological Properties, and Gel Characteristics
by
Xiong Li, Wanzi Yao, Cebin Hu, Congyu Lin, Lijun You and Jian Mao
Gels 2024, 10(7), 454; https://doi.org/10.3390/gels10070454 - 11 Jul 2024
Abstract
Polysaccharides derived from diverse sources exhibit distinct rheological and gel properties, exerting a profound impact on their applicability in the food industry. In this study, we collected five Gracilaria chouae samples from distinct geographical regions, namely Rizhao (RZ), Lianyungang (LYG), Ningde (ND), Beihai
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Polysaccharides derived from diverse sources exhibit distinct rheological and gel properties, exerting a profound impact on their applicability in the food industry. In this study, we collected five Gracilaria chouae samples from distinct geographical regions, namely Rizhao (RZ), Lianyungang (LYG), Ningde (ND), Beihai (BH), and a wild source from Beihai (BHW). We conducted analyses on the chemical composition, viscosity, and rheological properties, as well as gel properties, to investigate the influence of chemical composition on variations in gel properties. The results revealed that the total sugar, sulfate content, and monosaccharide composition of G. chouae polysaccharides exhibit similarity; however, their anhydrogalactose content varies within a range of 15.31% to 18.98%. The molecular weight distribution of G. chouae polysaccharides ranged from 1.85 to 2.09 × 103 kDa. The apparent viscosity of the LYG and BHW polysaccharides was relatively high, whereas that of RZ and ND was comparatively low. The gel strength displayed a similar trend. BHW and LYG exhibited solid-like behavior, while ND, RZ, and BH demonstrated liquid-like characteristics at low frequencies. The redundancy analysis (RDA) analysis revealed a positive correlation between the texture profile analysis (TPA) characteristics and anhydrogalactose. The study could provide recommendations for the diverse applications of G. chouae polysaccharides derived from different geographical regions.
Full article
(This article belongs to the Special Issue Food Gels: Structure and Function)
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Cationic Gas-Permeable Mold Fabrication Using Sol–Gel Polymerization for Nano-Injection Molding
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Sayaka Miura, Rio Yamagishi, Mano Ando, Arisa Teramae, Yuna Hachikubo, Yoshiyuki Yokoyama and Satoshi Takei
Gels 2024, 10(7), 453; https://doi.org/10.3390/gels10070453 - 11 Jul 2024
Abstract
Cationic gas-permeable molds fabricated via sol–gel polymerization undergo cationic polymerization using epoxide, resulting in gas permeability owing to their cross-linked structures. By applying this cationic gas-permeable mold to nano-injection molding, which is used for the mass production of resins, nano-protrusion structures with a
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Cationic gas-permeable molds fabricated via sol–gel polymerization undergo cationic polymerization using epoxide, resulting in gas permeability owing to their cross-linked structures. By applying this cationic gas-permeable mold to nano-injection molding, which is used for the mass production of resins, nano-protrusion structures with a height of approximately 300 nm and a pitch of approximately 400 nm were produced. The molding defects caused by gas entrapment in the air and cavities when using conventional gas-impermeable metal molds were improved, and the cationic gas-permeable mold could be continuously fabricated for 3000 shots under non-vacuum conditions. The results of the mechanical evaluations showed improved thermal stability and Martens hardness, which is expected to lead to the advanced production of resin nano-structures. Furthermore, the surface roughness of the nano-protrusion structures fabricated using injection molding improved the water contact angle by approximately 46°, contributing to the development of various hydrophobic materials in the future.
Full article
(This article belongs to the Special Issue Gel Formation and Processing Technologies for Material Applications)
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Nanocomposite Perfluorosulfonic Acid/Montmorillonite-Na+ Polymer Membrane as Gel Electrolyte in Hybrid Supercapacitors
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Borislava Mladenova, Galin Borisov, Mariela Dimitrova, Desislava Budurova, Maya Staneva, Filip Ublekov and Antonia Stoyanova
Gels 2024, 10(7), 452; https://doi.org/10.3390/gels10070452 - 10 Jul 2024
Abstract
Solid-state supercapacitors with gel electrolytes have emerged as a promising field for various energy storage applications, including electronic devices, electric vehicles, and mobile phones. In this study, nanocomposite gel membranes were fabricated using the solution casting method with perfluorosulfonic acid (PFSA) ionomer dispersion,
[...] Read more.
Solid-state supercapacitors with gel electrolytes have emerged as a promising field for various energy storage applications, including electronic devices, electric vehicles, and mobile phones. In this study, nanocomposite gel membranes were fabricated using the solution casting method with perfluorosulfonic acid (PFSA) ionomer dispersion, both with and without the incorporation of 10 wt.% montmorillonite (MMT). MMT, a natural clay known for its high surface area and layered structure, is expected to enhance the properties of supercapacitor systems. Manganese oxide, selected for its pseudocapacitive behavior in a neutral electrolyte, was synthesized via direct co-precipitation. The materials underwent structural and morphological characterization. For electrochemical evaluation, a two-electrode Swagelok cell was employed, featuring a carbon xerogel negative electrode, a manganese dioxide positive electrode, and a PFSA polymer membrane serving as both the electrolyte and separator. The membrane was immersed in a 1 M Na2SO4 solution before testing. A comprehensive electrochemical analysis of the hybrid cells was conducted and compared with a symmetric carbon/carbon supercapacitor. Cyclic voltammetric curves were recorded, and galvanostatic charge–discharge tests were conducted at various temperatures (20, 40, 60 °C). The hybrid cell with the PFSA/MMT 10 wt.% exhibited the highest specific capacitance and maintained its hybrid profile after prolonged cycling at elevated temperatures, highlighting the potential of the newly developed membrane.
Full article
(This article belongs to the Special Issue Gel Materials in Advanced Energy Systems)
Open AccessArticle
Coenzyme-A-Responsive Nanogel-Coated Electrochemical Sensor for Osteoarthritis-Detection-Based Genetic Models
by
Akhmad Irhas Robby, Songling Jiang, Eun-Jung Jin and Sung Young Park
Gels 2024, 10(7), 451; https://doi.org/10.3390/gels10070451 - 10 Jul 2024
Abstract
An electrochemical sensor sensitive to coenzyme A (CoA) was designed using a CoA-responsive polyallylamine–manganese oxide–polymer dot nanogel coated on the electrode surface to detect various genetic models of osteoarthritis (OA). The CoA-responsive nanogel sensor responded to the abundance of CoA in OA, causing
[...] Read more.
An electrochemical sensor sensitive to coenzyme A (CoA) was designed using a CoA-responsive polyallylamine–manganese oxide–polymer dot nanogel coated on the electrode surface to detect various genetic models of osteoarthritis (OA). The CoA-responsive nanogel sensor responded to the abundance of CoA in OA, causing the breakage of MnO2 in the nanogel, thereby changing the electroconductivity and fluorescence of the sensor. The CoA-responsive nanogel sensor was capable of detecting CoA depending on the treatment time and distinguishing the response towards different OA genetic models that contained different levels of CoA (wild type/WT, NudT7 knockout/N7KO, and Acot12 knockout/A12KO). The WT, N7KO, and A12KO had distinct resistances, which further increased as the incubation time were changed from 12 h (R12h = 2.11, 2.40, and 2.68 MΩ, respectively) to 24 h (R24h = 2.27, 2.59, and 2.92 MΩ, respectively) compared to the sensor without treatment (Rcontrol = 1.63 MΩ). To simplify its application, the nanogel sensor was combined with a wireless monitoring device to allow the sensing data to be directly transmitted to a smartphone. Furthermore, OA-indicated anabolic (Acan) and catabolic (Adamts5) factor transcription levels in chondrocytes provided evidence regarding CoA and nanogel interactions. Thus, this sensor offers potential usage in simple and sensitive OA diagnostics.
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(This article belongs to the Special Issue Recent Progress of Hydrogel Sensors and Biosensors)
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The Influence of Sulfation Degree of Glycosaminoglycan-Functionalized 3D Collagen I Networks on Cytokine Profiles of In Vitro Macrophage–Fibroblast Cocultures
by
Franziska Ullm, Alexander Renner, Uwe Freudenberg, Carsten Werner and Tilo Pompe
Gels 2024, 10(7), 450; https://doi.org/10.3390/gels10070450 - 9 Jul 2024
Abstract
Cell–cell interactions between fibroblasts and immune cells, like macrophages, are influenced by interaction with the surrounding extracellular matrix during wound healing. In vitro hydrogel models that mimic and modulate these interactions, especially of soluble mediators like cytokines, may allow for a more detailed
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Cell–cell interactions between fibroblasts and immune cells, like macrophages, are influenced by interaction with the surrounding extracellular matrix during wound healing. In vitro hydrogel models that mimic and modulate these interactions, especially of soluble mediators like cytokines, may allow for a more detailed investigation of immunomodulatory processes. In the present study, a biomimetic extracellular matrix model based on fibrillar 3D collagen I networks with a functionalization with heparin or 6-ON-desulfated heparin, as mimics of naturally occurring heparan sulfate, was developed to modulate cytokine binding effects with the hydrogel matrix. The constitution and microstructure of the collagen I network were found to be stable throughout the 7-day culture period. A coculture study of primary human fibroblasts/myofibroblasts and M-CSF-stimulated macrophages was used to show its applicability to simulate processes of progressed wound healing. The quantification of secreted cytokines (IL-8, IL-10, IL-6, FGF-2) in the cell culture supernatant demonstrated the differential impact of glycosaminoglycan functionalization of the collagen I network. Most prominently, IL-6 and FGF-2 were shown to be regulated by the cell culture condition and network constitution, indicating changes in paracrine and autocrine cell–cell communication of the fibroblast–macrophage coculture. From this perspective, we consider our newly established in vitro hydrogel model suitable for mechanistic coculture analyses of primary human cells to unravel the role of extracellular matrix factors in key events of tissue regeneration and beyond.
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(This article belongs to the Section Gel Applications)
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Preparation and Effect of CO2 Response Gel for Plugging Low-Permeability Reservoirs
by
Huipeng Wang, Changhua Yang, Yongwei Zhang and Chen Wang
Gels 2024, 10(7), 449; https://doi.org/10.3390/gels10070449 - 9 Jul 2024
Abstract
In order to solve the problem of gas channeling during CO2 flooding in low-permeability reservoirs, a novel CO2 responsive gel channeling system was prepared by using carrageenan, branched polyethylene imide and ethylenediamine under laboratory conditions. Based on the Box–Behnken response surface
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In order to solve the problem of gas channeling during CO2 flooding in low-permeability reservoirs, a novel CO2 responsive gel channeling system was prepared by using carrageenan, branched polyethylene imide and ethylenediamine under laboratory conditions. Based on the Box–Behnken response surface design method, the optimal synthesis concentration of the system was 0.5 wt% carrageenan, 2.5 wt% branchized polyethylenimide and 6.5 wt% ethylenediamine. The micromorphology of the system before and after response was characterized by scanning electron microscopy. The rheology and dehydration rate were tested under different conditions. The channeling performance and enhanced oil recovery effect of the gel system were simulated by a core displacement experiment. The experimental results show that the internal structure of the system changes from a disordered, smooth and loosely separated lamellae structure to a more uniform, complete and orderly three-dimensional network structure after exposure to CO2. The viscosity of the system was similar to aqueous solution before contact with CO2 and showed viscoelastic solid properties after contact with CO2. The experiment employing dehydration rates at different temperatures showed that the internal structure of the gel would change at a high temperature, but the gel system had a certain self-healing ability. The results of the displacement experiment show that the plugging rate of the gel system is stable at 85.32% after CO2 contact, and the recovery rate is increased by 17.06%, which provides an important guide for the development of low-permeability reservoirs.
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(This article belongs to the Special Issue Applications of Gels for Enhanced Oil Recovery)
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Innovative Approach to Accelerate Wound Healing: Synthesis and Validation of Enzymatically Cross-Linked COL–rGO Biocomposite Hydrogels
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Luisbel González, Víctor Espinoza, Mauricio Tapia, Valentina Aedo, Isleidy Ruiz, Manuel Meléndrez, Claudio Aguayo, Leonard I. Atanase and Katherina Fernández
Gels 2024, 10(7), 448; https://doi.org/10.3390/gels10070448 - 6 Jul 2024
Abstract
In this study, an innovative conductive hybrid biomaterial was synthetized using collagen (COL) and reduced graphene oxide (rGO) in order for it to be used as a wound dressing. The hydrogels were plasticized with glycerol and enzymatically cross-linked with horseradish peroxidase (HRP). A
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In this study, an innovative conductive hybrid biomaterial was synthetized using collagen (COL) and reduced graphene oxide (rGO) in order for it to be used as a wound dressing. The hydrogels were plasticized with glycerol and enzymatically cross-linked with horseradish peroxidase (HRP). A successful interaction among the components was demonstrated by FTIR, XRD, and XPS. It was demonstrated that increasing the rGO concentration led to higher conductivity and negative charge density values. Moreover, rGO also improved the stability of hydrogels, which was expressed by a reduction in the biodegradation rate. Furthermore, the hydrogel’s stability against the enzymatic action of collagenase type I was also strengthened by both the enzymatic cross-linking and the polymerization of dopamine. However, their absorption capacity, reaching values of 215 g/g, indicates the high potential of the hydrogels to absorb fluids. The rise of these properties positively influenced the wound closure process, achieving an 84.5% in vitro closure rate after 48 h. These findings clearly demonstrate that these original composite biomaterials can be a viable choice for wound healing purposes.
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(This article belongs to the Special Issue Composite Hydrogels for Biomedical Applications)
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Integrated In Vivo and In Vitro Evaluation of a Powder-to-Hydrogel, Film-Forming Polymer Complex Base with Tissue-Protective and Microbiome-Supportive Properties
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Daniel Banov, Guiyun Song, Zahraa Foraida, Oksana Tkachova, Oleksandr Zdoryk and Maria Carvalho
Gels 2024, 10(7), 447; https://doi.org/10.3390/gels10070447 - 5 Jul 2024
Abstract
The study aimed to perform a comprehensive in vitro and in vivo evaluation of a newly developed, patent-pending, powder-to-hydrogel, film-forming polymer complex base, which possesses tissue-protective and microbiome-supportive properties, and to compare its characteristics with poloxamer 407. The study used a combination of
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The study aimed to perform a comprehensive in vitro and in vivo evaluation of a newly developed, patent-pending, powder-to-hydrogel, film-forming polymer complex base, which possesses tissue-protective and microbiome-supportive properties, and to compare its characteristics with poloxamer 407. The study used a combination of in vitro assays, including tissue viability and cell migration, and in vivo wound healing evaluations in male diabetic mice. Microbiome dynamics at wound sites were also analyzed. The in vitro assays demonstrated that the polymer complex base was non-cytotoxic and that it enhanced cell migration over poloxamer 407. In vivo, the polymer complex base demonstrated superior wound healing capabilities, particularly in combination with misoprostol and phenytoin, as evidenced by the reduced wound area and inflammation scores. Microbiome analysis revealed favorable shifts in bacterial populations associated with the polymer complex base-treated wounds. The polymer complex base demonstrates clinical significance in wound care, potentially offering improved healing, safety and microbiome support. Its transformative properties and efficacy in drug delivery make it a promising candidate for advanced wound care applications, particularly in chronic wound management.
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(This article belongs to the Special Issue Hydrogels for Therapeutic Delivery: Current Developments and Future Directions)
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Development and Characterization of Hybrid Meat Analogs from Whey Protein-Mushroom Composite Hydrogels
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Ramdattu Santhapur, Disha Jayakumar and David Julian McClements
Gels 2024, 10(7), 446; https://doi.org/10.3390/gels10070446 - 5 Jul 2024
Abstract
There is a need to reduce the proportion of animal-derived food products in the human diet for sustainability and environmental reasons. However, it is also important that a transition away from animal-derived foods does not lead to any adverse nutritional effects. In this
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There is a need to reduce the proportion of animal-derived food products in the human diet for sustainability and environmental reasons. However, it is also important that a transition away from animal-derived foods does not lead to any adverse nutritional effects. In this study, the potential of blending whey protein isolate (WPI) with either shiitake mushroom (SM) or oyster mushroom (OM) to create hybrid foods with enhanced nutritional and physicochemical properties was investigated. The impact of OM or SM addition on the formation, microstructure, and physicochemical attributes of heat-set whey protein gels was therefore examined. The mushroom powders were used because they have relatively high levels of vitamins, minerals, phytochemicals, and dietary fibers, which may provide nutritional benefits, whereas the WPI was used to provide protein and good thermal gelation properties. A variety of analytical methods were used to characterize the structural and physicochemical properties of the WPI-mushroom hybrids, including confocal microscopy, particle electrophoresis, light scattering, proximate analysis, differential scanning calorimetry, thermogravimetric analysis, dynamic shear rheology, textural profile analysis, and colorimetry. The charge on whey proteins and mushroom particles went from positive to negative when the pH was raised from 3 to 9, but whey protein had a higher isoelectric point and charge magnitude. OM slightly increased the thermal stability of WPI, but SM had little effect. Both mushroom types decreased the lightness and increased the brownness of the whey protein gels. The addition of the mushroom powders also decreased the hardness and Young’s modulus of the whey protein gels, which may be because the mushroom particles acted as soft fillers. This study provides valuable insights into the formation of hybrid whey protein-mushroom products that have desirable physiochemical and nutritional attributes.
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(This article belongs to the Special Issue Properties and Structure of Plant-Based Emulsion Gels)
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Degradable Gel for Temporary Plugging in High Temperature Reservoir and Its Properties
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Fan Yang, Jinhua Liu, Renjing Ji, Xiaorong Yu, Huan Yang and Gaoshen Su
Gels 2024, 10(7), 445; https://doi.org/10.3390/gels10070445 - 5 Jul 2024
Abstract
Although various degradable gel materials have been developed for temporary plugging in oil fields, they often degrade too quickly in high-temperature environments. To address this issue, an unstable crosslinker was synthesized to prepare a high-temperature degradable gel. This gel does not degrade excessively
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Although various degradable gel materials have been developed for temporary plugging in oil fields, they often degrade too quickly in high-temperature environments. To address this issue, an unstable crosslinker was synthesized to prepare a high-temperature degradable gel. This gel does not degrade excessively fast at high temperatures. Temperature and crosslinker concentration are the primary factors influencing gel degradation time, followed by monomer and initiator concentrations. Increased temperature and decreased crosslinker concentration both reduce degradation time, which can be adjusted within the range of 90–130 °C by varying the crosslinker concentration. The molecular structure and thermal stability of the degradable gel were analyzed using FTIR, 13C NMR, and TG. Furthermore, the viscoelastic properties, compressive performance, plugging performance, and core damage performance of the gel were evaluated. Within the test range of 0.1–1000 Pa, the storage modulus is higher than the loss modulus. The gel prepared at 130 °C exhibited a compressive stress of 0.25 MPa at 50% strain. The plugging pressure of the gel in sand-filled tubes with varying permeabilities (538.2–2794.1 mD) exceeded 15 MPa while maintaining a core damage rate below 5%. SEM analysis indicated that the degradation mechanism of the gel may involve the collapse of its three-dimensional network structure due to the hydrolysis of amide groups in the crosslinker. The viscosity of the degradation liquid was below 11 mPa·s, enabling it to be brought back to the surface with the formation fluid without the need for further breaking operations.
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(This article belongs to the Special Issue Gels in the Oil Field)
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Physically Crosslinked Poly(methacrylic acid)/Gelatin Hydrogels with Excellent Fatigue Resistance and Shape Memory Properties
by
Vukasin Ugrinovic, Maja Markovic, Bojan Bozic, Vesna Panic and Djordje Veljovic
Gels 2024, 10(7), 444; https://doi.org/10.3390/gels10070444 - 4 Jul 2024
Abstract
Hydrogels endure various dynamic stresses, demanding robust mechanical properties. Despite significant advancements, matching hydrogels’ strength to biological tissues and plastics is often challenging without applying potentially harmful crosslinkers. Using hydrogen bonds as sacrificial bonds offers a promising strategy to produce tough, versatile hydrogels
[...] Read more.
Hydrogels endure various dynamic stresses, demanding robust mechanical properties. Despite significant advancements, matching hydrogels’ strength to biological tissues and plastics is often challenging without applying potentially harmful crosslinkers. Using hydrogen bonds as sacrificial bonds offers a promising strategy to produce tough, versatile hydrogels for biomedical and industrial applications. Poly(methacrylic acid) (PMA)/gelatin hydrogels were synthesized by thermally induced free-radical polymerization and crosslinked only by physical bonds, without adding any chemical crosslinker. The addition of gelatin increased the formation of hydrophobic domains in the structure of the hydrogels, which acted as permanent crosslinking points. The increase in PMA and gelatin contents generally led to a lower equilibrium water content (WC), higher thermal stability and better mechanical properties. The values of tensile strength and toughness reached up to 1.44 ± 0.17 MPa and 4.91 ± 0.51 MJ m−3, respectively, while the compressive modulus and strength reached up to 0.75 ± 0.06 MPa and 24.81 ± 5.85 MPa, respectively, with the WC being higher than 50 wt.%. The obtained values for compressive mechanical properties are comparable with super-strong hydrogels reported in the literature. In addition, hydrogels exhibited excellent fatigue resistance and biocompatibility, as well as great shape memory properties, which make them prominent candidates for a wide range of biomedical applications.
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(This article belongs to the Special Issue Synthesis and Applications of Hydrogels (2nd Edition))
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Synthesis of Modified Nano-Hydrotalcite Clay by Micellar Method and Its Application as Gel-like Crude Oil Flow Improver
by
Yingna Du, Michal Slaný, Tianbao Hu, Yubo Lian, Yingxue Bai, Congyu Ke and Gang Chen
Gels 2024, 10(7), 443; https://doi.org/10.3390/gels10070443 - 4 Jul 2024
Abstract
The network formed by wax precipitation at low temperature and colloid asphaltene at high temperature leads to poor fluidity of heavy oil, and the gelling characteristics of crude oil lead to pipeline blockage, which affects the exploitation, transportation and refining of crude oil.
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The network formed by wax precipitation at low temperature and colloid asphaltene at high temperature leads to poor fluidity of heavy oil, and the gelling characteristics of crude oil lead to pipeline blockage, which affects the exploitation, transportation and refining of crude oil. This work prepares a series of cationic surfactant-modified nano hydrotalcite (CSNH) to weaken the network structure and enhance the fluidity of the crude oil by the interaction of organic and inorganic functional groups on the CSNH surface and the components of the crude oil. The results show that CSNHs can all reduce the viscosity of crude oil from different oilfields, among which BTNH can reduce the viscosity of Yanglou (YL) crude oil by 98.8% (31 °C) and depress the pour point by 16.0 °C at most. In the investigation of the universality of crude oil, the modified hydrotalcite was applied to the mixed crude oil (CQH) of Changqing Oilfield, the crude oil (J76) of Jidong Oilfield, the high pour point oil (GN) of Huabei Oilfield, and the crude oil (HQ) of Tuha Oilfield. The viscosity reduction rates were 53.2%, 86.2%, 42.7%, and 63.8%, respectively. The characterization of this nano material confirms the modification of quaternary ammonium cationic surfactant on the surface, resulting in a smaller particle size, and the nano particles are stable under conventional conditions. The mechanism of viscosity and pour point reduction in crude oil by BTNH was discussed by DSC and optical microscopy analysis. The OH- and long-chain alkyl groups on the BTNH surface may interact with the resins, asphaltene and wax through hydrogen bonding and co-crystal, weakening or dispersing their aggregates, thereby improving the fluidity of crude oil. Finally, a cost evaluation was conducted on BTNH, providing useful support for subsequent promotion and application.
Full article
(This article belongs to the Special Issue Polymer Gels for the Oil and Gas Industry)
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Open AccessReview
Overview of Dynamic Bond Based Hydrogels for Reversible Adhesion Processes
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Ilaria Condò, Sara Maria Giannitelli, Daniela Lo Presti, Barbara Cortese and Ornella Ursini
Gels 2024, 10(7), 442; https://doi.org/10.3390/gels10070442 - 4 Jul 2024
Abstract
Polymeric hydrogels are soft materials with a three-dimensional (3D) hydrophilic network capable of retaining and absorbing large amounts of water or biological fluids. Due to their customizable properties, these materials are extensively studied for developing matrices for 3D cell culture scaffolds, drug delivery
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Polymeric hydrogels are soft materials with a three-dimensional (3D) hydrophilic network capable of retaining and absorbing large amounts of water or biological fluids. Due to their customizable properties, these materials are extensively studied for developing matrices for 3D cell culture scaffolds, drug delivery systems, and tissue engineering. However, conventional hydrogels still exhibit many drawbacks; thus, significant efforts have been directed towards developing dynamic hydrogels that draw inspiration from organisms’ natural self-repair abilities after injury. The self-healing properties of these hydrogels are closely associated with their ability to form, break, and heal dynamic bonds in response to various stimuli. The primary objective of this review is to provide a comprehensive overview of dynamic hydrogels by examining the types of chemical bonds associated with them and the biopolymers utilized, and to elucidate the chemical nature of dynamic bonds that enable the modulation of hydrogels’ properties. While dynamic bonds ensure the self-healing behavior of hydrogels, they do not inherently confer adhesive properties. Therefore, we also highlight emerging approaches that enable dynamic hydrogels to acquire adhesive properties.
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(This article belongs to the Special Issue Hydrogels: Synthesis, Characterization and Applications (2nd Edition))
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Effect of Sol–Gel Silica Matrices on the Chemical Properties of Adsorbed/Entrapped Compounds
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Ariela Burg, Krishna K. Yadav, Dan Meyerstein, Haya Kornweitz, Dror Shamir and Yael Albo
Gels 2024, 10(7), 441; https://doi.org/10.3390/gels10070441 - 2 Jul 2024
Abstract
The sol–gel process enables the preparation of silica-based matrices with tailored composition and properties that can be used in a variety of applications, including catalysis, controlled release, sensors, separation, etc. Commonly, it is assumed that silica matrices prepared via the sol–gel synthesis route
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The sol–gel process enables the preparation of silica-based matrices with tailored composition and properties that can be used in a variety of applications, including catalysis, controlled release, sensors, separation, etc. Commonly, it is assumed that silica matrices prepared via the sol–gel synthesis route are “inert” and, therefore, do not affect the properties of the substrate or the catalyst. This short review points out that porous silica affects the properties of adsorbed/entrapped species and, in some cases, takes an active part in the reactions. The charged matrix affects the diffusion of ions, thus affecting catalytic and adsorption processes. Furthermore, recent results point out that ≡Si-O. radicals are long-lived and participate in redox processes. Thus, clearly, porous silica is not an inert matrix as commonly considered.
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(This article belongs to the Special Issue Gel-Based Adsorbent Materials for Environmental Remediation)
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Stimulus-Responsive Hydrogels for Targeted Cancer Therapy
by
Raghu Solanki and Dhiraj Bhatia
Gels 2024, 10(7), 440; https://doi.org/10.3390/gels10070440 - 1 Jul 2024
Abstract
Cancer is a highly heterogeneous disease and remains a global health challenge affecting millions of human lives worldwide. Despite advancements in conventional treatments like surgery, chemotherapy, and immunotherapy, the rise of multidrug resistance, tumor recurrence, and their severe side effects and the complex
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Cancer is a highly heterogeneous disease and remains a global health challenge affecting millions of human lives worldwide. Despite advancements in conventional treatments like surgery, chemotherapy, and immunotherapy, the rise of multidrug resistance, tumor recurrence, and their severe side effects and the complex nature of the tumor microenvironment (TME) necessitates innovative therapeutic approaches. Recently, stimulus-responsive nanomedicines designed to target TME characteristics (e.g., pH alterations, redox conditions, enzyme secretion) have gained attention for their potential to enhance anticancer efficacy while minimizing the adverse effects of chemotherapeutics/bioactive compounds. Among the various nanocarriers, hydrogels are intriguing due to their high-water content, adjustable mechanical characteristics, and responsiveness to external and internal stimuli, making them promising candidates for cancer therapy. These properties make hydrogels an ideal nanocarrier for controlled drug release within the TME. This review comprehensively surveys the latest advancements in the area of stimulus-responsive hydrogels for cancer therapy, exploring various stimuli-responsive mechanisms, including biological (e.g., pH, redox), chemical (e.g., enzymes, glucose), and physical (e.g., temperature, light), as well as dual- or multi-stimuli responsiveness. Furthermore, this review addresses the current developments and challenges in hydrogels in cancer treatment. Our aim is to provide readers with a comprehensive understanding of stimulus-responsive hydrogels for cancer treatment, offering novel perspectives on their development for cancer therapy and other medical applications.
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(This article belongs to the Special Issue Stimuli-Responsive Composite Gels)
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Streamlining Skin Regeneration: A Ready-To-Use Silk Bilayer Wound Dressing
by
Anabela Veiga, Inês V. Silva, Juliana R. Dias, Nuno M. Alves, Ana L. Oliveira and Viviana P. Ribeiro
Gels 2024, 10(7), 439; https://doi.org/10.3390/gels10070439 - 30 Jun 2024
Abstract
Silk proteins have been highlighted in the past decade for tissue engineering (TE) and skin regeneration due to their biocompatibility, biodegradability, and exceptional mechanical properties. While silk fibroin (SF) has high structural and mechanical stability with high potential as an external protective layer,
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Silk proteins have been highlighted in the past decade for tissue engineering (TE) and skin regeneration due to their biocompatibility, biodegradability, and exceptional mechanical properties. While silk fibroin (SF) has high structural and mechanical stability with high potential as an external protective layer, traditionally discarded sericin (SS) has shown great potential as a natural-based hydrogel, promoting cell–cell interactions, making it an ideal material for direct wound contact. In this context, the present study proposes a new wound dressing approach by developing an SS/SF bilayer construct for full-thickness exudative wounds. The processing methodology implemented included an innovation element and the cryopreservation of the SS intrinsic secondary structure, followed by rehydration to produce a hydrogel layer, which was integrated with a salt-leached SF scaffold to produce a bilayer structure. In addition, a sterilization protocol was developed using supercritical technology (sCO2) to allow an industrial scale-up. The resulting bilayer material presented high porosity (>85%) and interconnectivity while promoting cell adhesion, proliferation, and infiltration of human dermal fibroblasts (HDFs). SS and SF exhibit distinct secondary structures, pore sizes, and swelling properties, opening new possibilities for dual-phased systems that accommodate the different needs of a wound during the healing process. The innovative SS hydrogel layer highlights the transformative potential of the proposed bilayer system for biomedical therapeutics and TE, offering insights into novel wound dressing fabrication.
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(This article belongs to the Special Issue Hydrogel for Tissue Engineering and Biomedical Therapeutics)
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Bio-Based Aerogels in Energy Storage Systems
by
Vilko Mandić, Arijeta Bafti, Ivana Panžić and Floren Radovanović-Perić
Gels 2024, 10(7), 438; https://doi.org/10.3390/gels10070438 - 30 Jun 2024
Abstract
Bio-aerogels have emerged as promising materials for energy storage, providing a sustainable alternative to conventional aerogels. This review addresses their syntheses, properties, and characterization challenges for use in energy storage devices such as rechargeable batteries, supercapacitors, and fuel cells. Derived from renewable sources
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Bio-aerogels have emerged as promising materials for energy storage, providing a sustainable alternative to conventional aerogels. This review addresses their syntheses, properties, and characterization challenges for use in energy storage devices such as rechargeable batteries, supercapacitors, and fuel cells. Derived from renewable sources (such as cellulose, lignin, and chitosan), bio-based aerogels exhibit mesoporosity, high specific surface area, biocompatibility, and biodegradability, making them advantageous for environmental sustainability. Bio-based aerogels serve as electrodes and separators in energy storage systems, offering desirable properties such as high specific surface area, porosity, and good electrical conductivity, enhancing the energy density, power density, and cycle life of devices. Recent advancements highlight their potential as anode materials for lithium-ion batteries, replacing non-renewable carbon materials. Studies have shown excellent cycling stability and rate performance for bio-aerogels in supercapacitors and fuel cells. The yield properties of these materials, primarily porosity and transport phenomena, demand advanced characterization methods, and their synthesis and processing methods significantly influence their production, e.g., sol–gel and advanced drying. Bio-aerogels represent a sustainable solution for advancing energy storage technologies, despite challenges such as scalability, standardization, and cost-effectiveness. Future research aims to improve synthesis methods and explore novel applications. Bio-aerogels, in general, provide a healthier path to technological progress.
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(This article belongs to the Special Issue Recent Progress and Development of Advanced Aerogels: Latest Processing Methods, Improved Properties and Application (2nd Edition))
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Biomimetic Hydrogel Strategies for Cancer Therapy
by
Awatef M. Alshehri and Otto C. Wilson, Jr.
Gels 2024, 10(7), 437; https://doi.org/10.3390/gels10070437 - 30 Jun 2024
Abstract
Recent developments in biomimetic hydrogel research have expanded the scope of biomedical technologies that can be used to model, diagnose, and treat a wide range of medical conditions. Cancer presents one of the most intractable challenges in this arena due to the surreptitious
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Recent developments in biomimetic hydrogel research have expanded the scope of biomedical technologies that can be used to model, diagnose, and treat a wide range of medical conditions. Cancer presents one of the most intractable challenges in this arena due to the surreptitious mechanisms that it employs to evade detection and treatment. In order to address these challenges, biomimetic design principles can be adapted to beat cancer at its own game. Biomimetic design strategies are inspired by natural biological systems and offer promising opportunities for developing life-changing methods to model, detect, diagnose, treat, and cure various types of static and metastatic cancers. In particular, focusing on the cellular and subcellular phenomena that serve as fundamental drivers for the peculiar behavioral traits of cancer can provide rich insights into eradicating cancer in all of its manifestations. This review highlights promising developments in biomimetic nanocomposite hydrogels that contribute to cancer therapies via enhanced drug delivery strategies and modeling cancer mechanobiology phenomena in relation to metastasis and synergistic sensing systems. Creative efforts to amplify biomimetic design research to advance the development of more effective cancer therapies will be discussed in alignment with international collaborative goals to cure cancer.
Full article
(This article belongs to the Special Issue Cancer Cell Biology in Biological Hydrogel)
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