Journal Description
Gels
Gels
is an international, peer-reviewed, open access journal on physical and chemical gels published monthly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High visibility: indexed within Scopus, SCIE (Web of Science), PubMed, PMC, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q1 (Polymer Science)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 11.1 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Testimonials: See what our editors and authors say about the Gels.
Impact Factor:
4.6 (2022);
5-Year Impact Factor:
5.2 (2022)
Latest Articles
A Review of High-Temperature Aerogels: Composition, Mechanisms, and Properties
Gels 2024, 10(5), 286; https://doi.org/10.3390/gels10050286 - 23 Apr 2024
Abstract
High-temperature aerogels have garnered significant attention as promising insulation materials in various industries such as aerospace, automotive manufacturing, and beyond, owing to their remarkable thermal insulation properties coupled with low density. With advancements in manufacturing techniques, the thermal resilience of aerogels has considerable
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High-temperature aerogels have garnered significant attention as promising insulation materials in various industries such as aerospace, automotive manufacturing, and beyond, owing to their remarkable thermal insulation properties coupled with low density. With advancements in manufacturing techniques, the thermal resilience of aerogels has considerable improvements. Notably, polyimide-based aerogels can endure temperatures up to 1000 °C, zirconia-based aerogels up to 1300 °C, silica-based aerogels up to 1500 °C, alumina-based aerogels up to 1800 °C, and carbon-based aerogels can withstand up to 2500 °C. This paper systematically discusses recent advancements in the thermal insulation performance of these five materials. It elaborates on the temperature resistance of aerogels and elucidates their thermal insulation mechanisms. Furthermore, it examines the impact of doping elements on the thermal conductivity of aerogels and consolidates various preparation methods aimed at producing aerogels capable of withstanding temperatures. In conclusion, by employing judicious composition design strategies, it is anticipated that the maximum tolerance temperature of aerogels can surpass 2500 °C, thus opening up new avenues for their application in extreme thermal environments.
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(This article belongs to the Special Issue Synthesis and Application of Aerogel)
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Open AccessArticle
Silicon-Doped Carbon Dots Crosslinked Carboxymethyl Cellulose Gel: Detection and Adsorption of Fe3+
by
Zhengdong Zhao, Yichang Jing, Yuan Shen, Yang Liu, Jiaqi Wang, Mingjian Ma, Jiangbo Pan, Di Wang, Chengyu Wang and Jian Li
Gels 2024, 10(5), 285; https://doi.org/10.3390/gels10050285 - 23 Apr 2024
Abstract
The excessive emission of iron will pollute the environment and harm human health, so the fluorescence detection and adsorption of Fe3+ are of great significance. In the field of water treatment, cellulose-based gels have attracted wide attention due to their excellent properties
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The excessive emission of iron will pollute the environment and harm human health, so the fluorescence detection and adsorption of Fe3+ are of great significance. In the field of water treatment, cellulose-based gels have attracted wide attention due to their excellent properties and environmental friendliness. If carbon dots are used as a crosslinking agent to form a gel with cellulose, it can not only improve mechanical properties but also show good biocompatibility, reactivity, and fluorescence properties. In this study, silicon-doped carbon dots/carboxymethyl cellulose gel (DCG) was successfully prepared by chemically crosslinking biomass-derived silicon-doped carbon dots with carboxymethyl cellulose. The abundant crosslinking points endow the gel with excellent mechanical properties, with a compressive strength reaching 294 kPa. In the experiment on adsorbing Fe3+, the theoretical adsorption capacity reached 125.30 mg/g. The introduction of silicon-doped carbon dots confers the gel with excellent fluorescence properties and a good selective response to Fe3+. It exhibits a good linear relationship within the concentration range of 0–100 mg/L, with a detection limit of 0.6595 mg/L. DCG appears to be a good application prospect in the adsorption and detection of Fe3+.
Full article
(This article belongs to the Special Issue Gels for Removal and Adsorption (2nd Edition))
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Open AccessReview
Liposome–Hydrogel Composites for Controlled Drug Delivery Applications
by
Roya Binaymotlagh, Farid Hajareh Haghighi, Laura Chronopoulou and Cleofe Palocci
Gels 2024, 10(4), 284; https://doi.org/10.3390/gels10040284 - 22 Apr 2024
Abstract
Various controlled delivery systems (CDSs) have been developed to overcome the shortcomings of traditional drug formulations (tablets, capsules, syrups, ointments, etc.). Among innovative CDSs, hydrogels and liposomes have shown great promise for clinical applications thanks to their cost-effectiveness, well-known chemistry and synthetic feasibility,
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Various controlled delivery systems (CDSs) have been developed to overcome the shortcomings of traditional drug formulations (tablets, capsules, syrups, ointments, etc.). Among innovative CDSs, hydrogels and liposomes have shown great promise for clinical applications thanks to their cost-effectiveness, well-known chemistry and synthetic feasibility, biodegradability, biocompatibility and responsiveness to external stimuli. To date, several liposomal- and hydrogel-based products have been approved to treat cancer, as well as fungal and viral infections, hence the integration of liposomes into hydrogels has attracted increasing attention because of the benefit from both of them into a single platform, resulting in a multifunctional drug formulation, which is essential to develop efficient CDSs. This short review aims to present an updated report on the advancements of liposome–hydrogel systems for drug delivery purposes.
Full article
(This article belongs to the Special Issue Liposomal and Ethosomal Gels: From Design to Application (2nd Edition))
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Open AccessArticle
High Modulus, Strut-like poly(ether ether ketone) Aerogels Produced from a Benign Solvent
by
Glenn A. Spiering, Garrett F. Godshall and Robert B. Moore
Gels 2024, 10(4), 283; https://doi.org/10.3390/gels10040283 - 22 Apr 2024
Abstract
Poly(ether ether ketone) (PEEK) was found to form gels in the benign solvent 1,3-diphenylacetone (DPA). Gelation of PEEK in DPA was found to form an interconnected, strut-like morphology composed of polymer axialites. To our knowledge, this is the first report of a strut-like
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Poly(ether ether ketone) (PEEK) was found to form gels in the benign solvent 1,3-diphenylacetone (DPA). Gelation of PEEK in DPA was found to form an interconnected, strut-like morphology composed of polymer axialites. To our knowledge, this is the first report of a strut-like morphology for PEEK aerogels. PEEK/DPA gels were prepared by first dissolving PEEK in DPA at 320 °C. Upon cooling to 50 °C, PEEK crystallizes and forms a gel in DPA. The PEEK/DPA phase diagram indicated that phase separation occurs by solid–liquid phase separation, implying that DPA is a good solvent for PEEK. The Flory–Huggins interaction parameter, calculated as χ12 = 0.093 for the PEEK/DPA system, confirmed that DPA is a good solvent for PEEK. PEEK aerogels were prepared by solvent exchanging DPA to water then freeze-drying. PEEK aerogels were found to have densities between 0.09 and 0.25 g/cm3, porosities between 80 and 93%, and surface areas between 200 and 225 m2/g, depending on the initial gel concentration. Using nitrogen adsorption analyses, PEEK aerogels were found to be mesoporous adsorbents, with mesopore sizes of about 8 nm, which formed between stacks of platelike crystalline lamellae. Scanning electron microscopy and X-ray scattering were utilized to elucidate the hierarchical structure of the PEEK aerogels. Morphological analysis found that the PEEK/DPA gels were composed of a highly nucleated network of PEEK axialites (i.e., aggregates of stacked crystalline lamellae). The highly connected axialite network imparted robust mechanical properties on PEEK aerogels, which were found to densify less upon freeze-drying than globular PEEK aerogel counterparts gelled from dichloroacetic acid (DCA) or 4-chlorphenol (4CP). PEEK aerogels formed from DPA were also found to have a modulus–density scaling that was far more efficient in supporting loads than the poorly connected aerogels formed from PEEK/DCA or PEEK/4CP solutions. The strut-like morphology in these new PEEK aerogels also significantly improved the modulus to a degree that is comparable to high-performance crosslinked aerogels based on polyimide and polyurea of comparable densities.
Full article
(This article belongs to the Special Issue Advances in Synthetic and Bio-Based Aerogels: Mechanical Properties, Thermal Insulation, and Environmental Remediation)
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Open AccessArticle
Influence of Gelatin and Propolis Extract on Honey Gummy Jelly Properties: Optimization Using D-Optimal Mixture Design
by
Kultida Kaewpetch, Saowapa Yolsuriyan, Terd Disayathanoowat, Patcharin Phokasem, Taruedee Jannu, Gerry Renaldi and Rajnibhas Sukeaw Samakradhamrongthai
Gels 2024, 10(4), 282; https://doi.org/10.3390/gels10040282 - 21 Apr 2024
Abstract
Gelatin is commonly used as a gelling agent in gummy candy. Honey and bee products are valuable and rich sources of biologically active substances. In this study, the influence of gelatin and propolis extract on honey gummy jelly (HGJ) properties was investigated. Honey
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Gelatin is commonly used as a gelling agent in gummy candy. Honey and bee products are valuable and rich sources of biologically active substances. In this study, the influence of gelatin and propolis extract on honey gummy jelly (HGJ) properties was investigated. Honey (28–32%), xylitol (13–17%), and gelatin (6–10%) were utilized to develop HGJ products by mixture design methodology. Subsequently, the optimized formulation of HGJ was fortified with 1% and 2% propolis extract to enhance its phytochemicals and antimicrobial activities. The variation in the ingredients significantly affected the physicochemical, textural, and sensory properties of the HGJ. The optimized HGJ formulation consisted of honey (32%), xylitol (14%), and gelatin (7%) and exhibited 13.35 × 103 g.force of hardness, −0.56 × 103 g.sec of adhesiveness, 11.96 × 103 N.mm of gumminess, 0.58 of resilience, and a moderate acceptance score (6.7–7.5). The fortification of HGJ with propolis extract significantly increased its phytochemical properties. Furthermore, the incorporation of propolis extract (2%) into the HGJ was able to significantly inhibit the growth of Gram-positive (Streptococcus mutans and Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The mixture of gelatin, xylitol, honey, and propolis extract can be utilized to develop a healthy gummy product with acceptable physicochemical, textural, and sensory qualities.
Full article
Open AccessArticle
Active Fish Gelatin/Chitosan Blend Film Incorporated with Guava Leaf Powder Carbon Dots: Properties, Release and Antioxidant Activity
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Gokulprasanth Murugan, Krisana Nilsuwan, Thummanoon Prodpran, Arunachalasivamani Ponnusamy, Jong-Whan Rhim, Jun Tae Kim and Soottawat Benjakul
Gels 2024, 10(4), 281; https://doi.org/10.3390/gels10040281 - 21 Apr 2024
Abstract
Active packaging is an innovative approach to prolonge the shelf-life of food products while ensuring their quality and safety. Carbon dots (CDs) from biomass as active fillers for biopolymer films have been introduced to improve their bioactivities as well as properties. Gelatin/chitosan (G/C)
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Active packaging is an innovative approach to prolonge the shelf-life of food products while ensuring their quality and safety. Carbon dots (CDs) from biomass as active fillers for biopolymer films have been introduced to improve their bioactivities as well as properties. Gelatin/chitosan (G/C) blend films containing active guava leaf powder carbon dots (GL-CDs) at various levels (0–3%, w/w) were prepared by the solvent casting method and characterized. Thickness of the control increased from 0.033 to 0.041 mm when 3% GL-CDs were added (G/C-CD-3%). Young’s modulus of the resulting films increased (485.67–759.00 MPa), whereas the tensile strength (26.92–17.77 MPa) and elongation at break decreased (14.89–5.48%) as the GL-CDs’ level upsurged (p < 0.05). Water vapor barrier property and water contact angle of the film were enhanced when incorporated with GL-CDs (p < 0.05). GL-CDs had a negligible impact on film microstructure, while GL-CDs interacted with gelatin or chitosan, as determined by FTIR. The release of GL-CDs from blend films was more pronounced in water than in alcoholic solutions (10–95% ethanol). The addition of GL-CDs improved the UV light barrier properties and antioxidant activities of the resultant films in a dose-dependent manner. Thus, GL-CD-added gelatin/chitosan blend films with antioxidant activities could be employed as potential active packaging for the food industry.
Full article
(This article belongs to the Special Issue Marine Biopolymers-Based Hydrogels, Xerogels and Aerogels: Preparation and Applications)
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Novel Injectable Hydrogel Formulations and Gas Chromatography Analysis of the Residual Crosslinker in Formulations Intended for Pharmaceutical and Cosmetic Applications
by
Fatimah Rashid, Paul Carter and Stephen Childs
Gels 2024, 10(4), 280; https://doi.org/10.3390/gels10040280 - 21 Apr 2024
Abstract
Novel hyaluronic acid (HA) crosslinked with pentaerythritol tetra-acrylate (PT) injectable hydrogels was invented. These injectable hydrogel/dermal filler formulations were synthesised using HA and the acrylate PT as a crosslinker under basic pH conditions using thermal crosslinking methods (oven heating), which provides a simple,
[...] Read more.
Novel hyaluronic acid (HA) crosslinked with pentaerythritol tetra-acrylate (PT) injectable hydrogels was invented. These injectable hydrogel/dermal filler formulations were synthesised using HA and the acrylate PT as a crosslinker under basic pH conditions using thermal crosslinking methods (oven heating), which provides a simple, safe, and eco-friendly method for crosslinking in 4 h under 45 °C. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses were conducted to represent the difference between the formulations in terms of peak formation and pore size, respectively. The crosslinking was partial as is considered to be typical for dermal injectable fillers. The rheological properties of these formulations showed that these novel dermal injectables are highly promising, and the newly developed fillers could be used with better results for dermal anti-wrinkle corrections, shaping, and volumising reasons. Furthermore, crosslinker (PT) residual analysis was carried out to state the formulations that are valid and acceptable for intradermal usage. The results from the GC method validation revealed it was a suitable method for this study. The GC analysis of all five injectable hydrogel/filler formulations demonstrated the formulations HA-PT 1, 2, 3 and 4 were formulated using (0.05–0.1)% w/w PT containing residual PT monomers within the safe limits that were determined to be below (0.008% w/w). This work has shown the development of a novel injectable hydrogel/filler formulation for pharmaceutical and cosmetic applications can be prepared in a more sustainable and simple way using pentaerythritol tetra-acrylate as a crosslinker agent, which holds great promise for the industry’s future advancement.
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(This article belongs to the Special Issue Hydrogels: Synthesis, Characterization and Applications (2nd Edition))
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Open AccessArticle
Polyhedral Oligomeric Sesquioxane Cross-Linked Chitosan-Based Multi-Effective Aerogel Preparation and Its Water-Driven Recovery Mechanism
by
Yang Liu, Mingjian Ma, Yuan Shen, Zhengdong Zhao, Xuefei Wang, Jiaqi Wang, Jiangbo Pan, Di Wang, Chengyu Wang and Jian Li
Gels 2024, 10(4), 279; https://doi.org/10.3390/gels10040279 - 20 Apr 2024
Abstract
The use of environmentally friendly and non-toxic biomass-based interfacial solar water evaporators has been widely reported as a method for water purification in recent years. However, the poor stability of the water transport layer made from biomass materials and its susceptibility to deformation
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The use of environmentally friendly and non-toxic biomass-based interfacial solar water evaporators has been widely reported as a method for water purification in recent years. However, the poor stability of the water transport layer made from biomass materials and its susceptibility to deformation when exposed to harsh environments limit its practical application. To address this issue, water-driven recovery aerogel (PCS) was prepared by cross-linking epoxy-based polyhedral oligomeric silsesquioxane (EP-POSS) epoxy groups with chitosan (CS) amino groups. The results demonstrate that PCS exhibits excellent water-driven recovery performance, regaining its original volume within a very short time (1.9 s) after strong compression (ε > 80%). Moreover, PCS has a water absorption rate of 2.67 mm s−1 and exhibits an excellent water absorption capacity of 22.09 g g−1 even after ten cycles of absorption-removal. Furthermore, a photothermal evaporator (PCH) was prepared by loading the top layer with hydrothermally reacted tannins (HAs) and Zn2+ complexes. The results indicate that PCH achieves an impressive evaporation rate of 1.89 kg m−2 h−1 under one sun illumination. Additionally, due to the antimicrobial properties of Zn2+, PCH shows inhibitory effects against Staphylococcus aureus and Escherichia coli, thereby extending the application of solar water evaporators to include antimicrobial purification in natural waters.
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(This article belongs to the Special Issue Gels for Removal and Adsorption (2nd Edition))
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In Vitro Antibacterial and Anti-Inflammatory Properties of Imidazolium Poly(ionic liquids) Microspheres Loaded in GelMA-PEG Hydrogels
by
Chao Zhou, Mengdi Sun, Danni Wang, Mingmei Yang, Jia Ling Celestine Loh, Yawen Xu and Ruzhi Zhang
Gels 2024, 10(4), 278; https://doi.org/10.3390/gels10040278 - 20 Apr 2024
Abstract
Repairing damaged tissue caused by bacterial infection poses a significant challenge. Traditional antibacterial hydrogels typically incorporate various components such as metal antimicrobials, inorganic antimicrobials, organic antimicrobials, and more. However, drawbacks such as the emergence of multi-drug resistance to antibiotics, the low antibacterial efficacy
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Repairing damaged tissue caused by bacterial infection poses a significant challenge. Traditional antibacterial hydrogels typically incorporate various components such as metal antimicrobials, inorganic antimicrobials, organic antimicrobials, and more. However, drawbacks such as the emergence of multi-drug resistance to antibiotics, the low antibacterial efficacy of natural agents, and the potential cytotoxicity associated with metal antibacterial nanoparticles in hydrogels hindered their broader clinical application. In this study, we successfully developed imidazolium poly(ionic liquids) (PILs) polymer microspheres (APMs) through emulsion polymerization. These APMs exhibited notable antibacterial effectiveness and demonstrated minimal cell toxicity. Subsequently, we integrated the APMs into a gelatin methacryloyl (GelMA)—polyethylene glycol (PEG) hydrogel. This composite hydrogel not only showcased strong antibacterial and anti-inflammatory properties but also facilitated the migration of human skin fibroblasts (HSF) and human umbilical vein endothelial cells (HUVECs) and promoted osteogenic differentiation in vitro.
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(This article belongs to the Special Issue Hydrogel and Membrane Dressings for Antibacterial Applications)
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Determination of Density of Starch Hydrogel Microspheres from Sedimentation Experiments Using Non-Stokes Drag Coefficient
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Margherita Cretella, Mina Fazilati, Nedim Krcic, Ivan Argatov and Vitaly Kocherbitov
Gels 2024, 10(4), 277; https://doi.org/10.3390/gels10040277 - 19 Apr 2024
Abstract
Sedimentation is an important property of colloidal systems that should be considered when designing pharmaceutical formulations. In pharmaceutical applications, sedimentation is normally described using Stokes’ law, which assumes laminar flow of fluid. In this work we studied swelling and hydration of spherical cross-linked
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Sedimentation is an important property of colloidal systems that should be considered when designing pharmaceutical formulations. In pharmaceutical applications, sedimentation is normally described using Stokes’ law, which assumes laminar flow of fluid. In this work we studied swelling and hydration of spherical cross-linked amorphous starch microspheres in pure water, solutions of sodium chloride, and in pH-adjusted aqueous solutions. We demonstrated that Reynolds numbers obtained in these experiments correspond to the transition regime between the laminar flow and the turbulent flow and, hence, expressions based on the non-Stokes drag coefficient should be used for calculations of sedimentation velocity from known density or for assessment of density from observed sedimentation velocity. The density of starch microparticles hydrated in water was about 1050 kg/m3, while densities obtained from experiment with other liquids were dependent on the liquids’ densities. The data indicate that the swelling of the cross-linked starch microparticles as characterized by their densities is not sensitive to pH and salt concentration in the studied range of these parameters.
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(This article belongs to the Section Gel Analysis and Characterization)
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Open AccessArticle
Comprehensive Evaluation of Injectability Attributes in OxiFree™ Dermal Fillers: MaiLi® Product Variants and Clinical Case Reports
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Patrick Micheels, Alexandre Porcello, Thierry Bezzola, Daniel Perrenoud, Marie-Odile Christen, Lee Ann Applegate and Alexis Laurent
Gels 2024, 10(4), 276; https://doi.org/10.3390/gels10040276 - 19 Apr 2024
Abstract
Dermal filler injectability is a critical factor for commercial product adoption by medical aesthetic professionals and for successful clinical administration. We have previously reported (in vitro and ex vivo) cross-linked hyaluronic acid (HA)-based dermal filler benchmarking in terms of manual and automated injectability
[...] Read more.
Dermal filler injectability is a critical factor for commercial product adoption by medical aesthetic professionals and for successful clinical administration. We have previously reported (in vitro and ex vivo) cross-linked hyaluronic acid (HA)-based dermal filler benchmarking in terms of manual and automated injectability requirements. To further enhance the function-oriented product characterization workflows and the clinical relevance of dermal filler injectability assessments, the aim of this study was to perform in vivo evaluations. Therefore, several variants of the MaiLi® product range (OxiFree™ technology) were characterized in vitro and in vivo in terms of injectability attributes, with a focus on hydrogel system homogeneity and ease of injection. Firstly, standardized in vitro assays were performed in SimSkin® cutaneous equivalents, with variations of the clinical injector, injection site, and injection technique. Then, automated injections in SimSkin® cutaneous equivalents were comparatively performed in a texture analysis setup to obtain fine-granulometry injection force profile results. Finally, five female participants were recruited for the in vivo arm of the study (case reports), with variations of the clinical injector, injection site, and injection technique. Generally, the obtained quantitative force values and injection force profiles were critically appraised from a translational viewpoint, based on discussions around the OxiFree™ manufacturing technology and on in-use specialized clinician feedback. Overall, the present study outlined a notable level of homogeneity across the MaiLi® product range in terms of injectability attributes, as well as consistently high ease of administration by medical aesthetic clinicians.
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(This article belongs to the Special Issue Current Directions and Prospects of Hydrogels for Biomedical Applications)
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Open AccessCommunication
Dried Porous Biomaterials from Mealworm Protein Gels: Proof of Concept and Impact of Drying Method on Structural Properties and Zinc Retention
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Martina Klost, Claudia Keil and Pavel Gurikov
Gels 2024, 10(4), 275; https://doi.org/10.3390/gels10040275 - 18 Apr 2024
Abstract
Dried porous materials can be found in a wide range of applications. So far, they are mostly prepared from inorganic or indigestible raw materials. The aim of the presented study was to provide a proof of concept for (a) the suitability of mealworm
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Dried porous materials can be found in a wide range of applications. So far, they are mostly prepared from inorganic or indigestible raw materials. The aim of the presented study was to provide a proof of concept for (a) the suitability of mealworm protein gels to be turned into dried porous biomaterials by either a combination of solvent exchange and supercritical drying to obtain aerogels or by lyophilization to obtain lyophilized hydrogels and (b) the suitability of either drying method to retain trace elements such as zinc in the gels throughout the drying process. Hydrogels were prepared from mealworm protein, subsequently dried using either method, and characterized via FT-IR, BET volume, and high-resolution scanning electron microscopy. Retention of zinc was evaluated via energy-dispersive X-ray spectroscopy. Results showed that both drying methods were suitable for obtaining dried porous biomaterials and that the drying method mainly influenced the overall surface area and pore hydrophobicity but not the secondary structure of the proteins in the gels or their zinc content after drying. Therefore, a first proof of concept for utilizing mealworm protein hydrogels as a base for dried porous biomaterials was successful and elucidated the potential of these materials as future sustainable alternatives to more conventional dried porous materials.
Full article
(This article belongs to the Special Issue International Perspectives on Aerogels)
Open AccessArticle
Optimized Synthesis of Poly(Lactic Acid) Nanoparticles for the Encapsulation of Flutamide
by
Duarte Almeida, Mariana Dias, Beatriz Teixeira, Carolina Frazão, Mónica Almeida, Gil Gonçalves, Miguel Oliveira and Ricardo J. B. Pinto
Gels 2024, 10(4), 274; https://doi.org/10.3390/gels10040274 - 18 Apr 2024
Abstract
Biopolymeric nanoparticles (NPs) have gained significant attention in several areas as an alternative to synthetic polymeric NPs due to growing environmental and immunological concerns. Among the most promising biopolymers is poly(lactic acid) (PLA), with a reported high degree of biocompatibility and biodegradability. In
[...] Read more.
Biopolymeric nanoparticles (NPs) have gained significant attention in several areas as an alternative to synthetic polymeric NPs due to growing environmental and immunological concerns. Among the most promising biopolymers is poly(lactic acid) (PLA), with a reported high degree of biocompatibility and biodegradability. In this work, PLA NPs were synthesized according to a controlled gelation process using a combination of single-emulsion and nanoprecipitation methods. This study evaluated the influence of several experimental parameters for accurate control of the PLA NPs’ size distribution and aggregation. Tip sonication (as the stirring method), a PLA concentration of 10 mg/mL, a PVA concentration of 2.5 mg/mL, and low-molecular-weight PLA (Mw = 5000) were established as the best experimental conditions to obtain monodisperse PLA NPs. After gelification process optimization, flutamide (FLU) was used as a model drug to evaluate the encapsulation capability of the PLA NPs. The results showed an encapsulation efficiency of 44% for this cytostatic compound. Furthermore, preliminary cell viability tests showed that the FLU@PLA NPs allowed cell viabilities above 90% up to a concentration of 20 mg/L. The comprehensive findings showcase that the PLA NPs fabricated using this straightforward gelification method hold promise for encapsulating cytostatic compounds, offering a novel avenue for precise drug delivery in cancer therapy.
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(This article belongs to the Special Issue Advanced Hydrogels for Tissue Engineering and Drug Delivery)
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Effect of Callus Cell Immobilization on the Textural and Rheological Properties, Loading, and Releasing of Grape Seed Extract from Pectin Hydrogels
by
Elena Günter, Oxana Popeyko, Fedor Vityazev and Sergey Popov
Gels 2024, 10(4), 273; https://doi.org/10.3390/gels10040273 - 17 Apr 2024
Abstract
The purpose of the present study was to prepare pectin hydrogels with immobilized Lemna minor callus cells and to identify the effect of cell immobilization on the textural, rheological, and swelling properties; loading; and releasing of grape seed extract (GSE) from the hydrogels.
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The purpose of the present study was to prepare pectin hydrogels with immobilized Lemna minor callus cells and to identify the effect of cell immobilization on the textural, rheological, and swelling properties; loading; and releasing of grape seed extract (GSE) from the hydrogels. Hardness, adhesiveness, elasticity, the strength of linkage, and complex viscosity decreased with increasing cell content in the hydrogels based on pectin with a degree of methyl esterification (DM) of 5.7% (TVC) and during incubation in gastrointestinal fluids. An increase in the rheological properties and fragility of pectin/callus hydrogels based on pectin with a DM of 33.0% (CP) was observed at a cell content of 0.4 g/mL. TVC-based pectin/callus beads increased their swelling in gastrointestinal fluids as cell content increased. TVC-based beads released GSE very slowly into simulated gastric and intestinal fluids, indicating controlled release. The GSE release rate in colonic fluid decreased with increasing cell content, which was associated with the accumulation of GSE in cells. CP-based beads released GSE completely in the intestinal fluid due to weak textural characteristics and rapid degradation within 10 min. Pectin/callus hydrogels have the ability to preserve GSE for a long time and may have great potential for the development of proanthocyanidin delivery systems due to their novel beneficial physicochemical and textural properties.
Full article
(This article belongs to the Special Issue Recent Developments in Food Gels (2nd Edition))
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Cytotoxicity and Degradation Resistance of Cryo- and Hydrogels Based on Carboxyethylchitosan at Different pH Values
by
Elena Blinova, Anastasia Korel, Ekaterina Zemlyakova, Alexander Pestov, Alexander Samokhin, Maxim Zelikman, Vadim Tkachenko, Viktoria Bets, Elena Arzhanova and Ekaterina Litvinova
Gels 2024, 10(4), 272; https://doi.org/10.3390/gels10040272 - 17 Apr 2024
Abstract
Background: The use of chitosan-based gels is still limited due to their restricted solubility in acid solutions, where the molecules have a positive charge. The functionalization of chitosan makes it possible to significantly expand the possibilities of using both the polymer itself and
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Background: The use of chitosan-based gels is still limited due to their restricted solubility in acid solutions, where the molecules have a positive charge. The functionalization of chitosan makes it possible to significantly expand the possibilities of using both the polymer itself and hydrogels based on its derivatives. Objective: To evaluate the effect of the conditions for the production of cryo- and hydrogels based on carboxyethylchitosan (CEC) crosslinked with glutaraldehyde on gel swelling and its resistance to degradation depending on pH and cytotoxic effects and to test the hypothesis that the amount of crosslinking agent during synthesis may affect the cytotoxicity of the gel. Methods: Gels’ swelling values and degradation resistance were determined using the gravimetric method. The cytotoxic effect was evaluated during the co-cultivation of gels in the presence of human fibroblasts using light optical microscopy and flow cytometry. Results: All CEC-based cryogels had a higher equilibrium swelling value and degradation time than the CEC hydrogel in the pH range from 4.6 to 8.0. This demonstrates the superiority of cryogels relative to CEC-based hydrogels in terms of swelling potential and degradation resistance, while an increase in the number of crosslinks with glutaraldehyde contributes to longer swelling of the cryogel. The positive control (intact fibroblasts) and all gel samples were statistically identical in the number of viable cells. On the third day, the viability of the fibroblast cells was consistently high (above 95%) and did not differ between all tested CEC-based gels. And in general, the cell morphology analysis results corresponded with the results obtained in the flow cytometry-based cytotoxicity test. We also did not find proof in our experiment to support our hypothesis that the amount of crosslinking agent during synthesis may affect the cytotoxicity of the material.
Full article
(This article belongs to the Special Issue Polysaccharide Gels and Beyond: From the Synthesis to Application)
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Exploring the Model of Cefazolin Released from Jellyfish Gelatin-Based Hydrogels as Affected by Glutaraldehyde
by
Wiriya Charoenchokpanich, Pratchaya Muangrod, Sittiruk Roytrakul, Vilai Rungsardthong, Benjamaporn Wonganu, Sawanya Charoenlappanit, Federico Casanova and Benjawan Thumthanaruk
Gels 2024, 10(4), 271; https://doi.org/10.3390/gels10040271 - 17 Apr 2024
Abstract
Due to its excellent biocompatibility and ease of biodegradation, jellyfish gelatin has gained attention as a hydrogel. However, hydrogel produced from jellyfish gelatin has not yet been sufficiently characterized. Therefore, this research aims to produce a jellyfish gelatin-based hydrogel. The gelatin produced from
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Due to its excellent biocompatibility and ease of biodegradation, jellyfish gelatin has gained attention as a hydrogel. However, hydrogel produced from jellyfish gelatin has not yet been sufficiently characterized. Therefore, this research aims to produce a jellyfish gelatin-based hydrogel. The gelatin produced from desalted jellyfish by-products varied with the part of the specimen and extraction time. Hydrogels with gelatin: glutaraldehyde ratios of 10:0.25, 10:0.50, and 10:1.00 (v/v) were characterized, and their cefazolin release ability was determined. The optimal conditions for gelatin extraction and chosen for the development of jellyfish hydrogels (JGel) included the use of the umbrella part of desalted jellyfish by-products extracted for 24 h (WU24), which yielded the highest gel strength (460.02 g), viscosity (24.45 cP), gelling temperature (12.70 °C), and melting temperature (22.48 °C). The quantities of collagen alpha−1(XXVIII) chain A, collagen alpha−1(XXI) chain, and collagen alpha−2(IX) chain in WU24 may influence its gel properties. Increasing the glutaraldehyde content in JGel increased the gel fraction by decreasing the space between the protein chains and gel swelling, as glutaraldehyde binds with lateral amino acid residues and produces a stronger network. At 8 h, more than 80% of the cefazolin in JGel (10:0.25) was released, which was higher than that released from bovine hydrogel (52.81%) and fish hydrogel (54.04%). This research is the first report focused on the production of JGel using glutaraldehyde as a cross-linking agent.
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(This article belongs to the Special Issue Gels in Medicine and Pharmacological Therapies (2nd Edition))
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Shape Memory Hydrogels for Biomedical Applications
by
Aleeza Farrukh and Sana Nayab
Gels 2024, 10(4), 270; https://doi.org/10.3390/gels10040270 - 17 Apr 2024
Abstract
The ability of shape memory polymers to change shape upon external stimulation makes them exceedingly useful in various areas, from biomedical engineering to soft robotics. Especially, shape memory hydrogels (SMHs) are well-suited for biomedical applications due to their inherent biocompatibility, excellent shape morphing
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The ability of shape memory polymers to change shape upon external stimulation makes them exceedingly useful in various areas, from biomedical engineering to soft robotics. Especially, shape memory hydrogels (SMHs) are well-suited for biomedical applications due to their inherent biocompatibility, excellent shape morphing performance, tunable physiochemical properties, and responsiveness to a wide range of stimuli (e.g., thermal, chemical, electrical, light). This review provides an overview of the unique features of smart SMHs from their fundamental working mechanisms to types of SMHs classified on the basis of applied stimuli and highlights notable clinical applications. Moreover, the potential of SMHs for surgical, biomedical, and tissue engineering applications is discussed. Finally, this review summarizes the current challenges in synthesizing and fabricating reconfigurable hydrogel-based interfaces and outlines future directions for their potential in personalized medicine and clinical applications.
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(This article belongs to the Special Issue Properties and Applications of Biomaterials Related to Gels (2nd Edition))
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The Injection of Gels Through an Intact Annulus Maintains Biomechanical Performance without Extrusion Risk
by
Hans-Joachim Wilke, Holger Fuchs, Karin Benz, Juergen Mollenhauer, Christoph Gaissmaier, Frank Heuer and Cornelia Neidlinger-Wilke
Gels 2024, 10(4), 269; https://doi.org/10.3390/gels10040269 - 17 Apr 2024
Abstract
For autologous-disc-derived chondrocyte transplantation (ADCT) a transglutaminase crosslinked gelatine gel and an albumin hyaluronic acid gel, crosslinked with bis-thio-polyethylene glycol, were injected through a syringe into a degenerated intervertebral disc, where they solidified in situ. This biomechanical in vitro study with lumbar bovine
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For autologous-disc-derived chondrocyte transplantation (ADCT) a transglutaminase crosslinked gelatine gel and an albumin hyaluronic acid gel, crosslinked with bis-thio-polyethylene glycol, were injected through a syringe into a degenerated intervertebral disc, where they solidified in situ. This biomechanical in vitro study with lumbar bovine motion segments evaluated disc height changes, motion characteristics in a quasi-static spine loading simulators, and the potential extrusion risk of these biomaterials in a complex dynamic multi-axial loading set-up with 100,000 loading cycles. After the injection and formation of the gel in the center of the nucleus, the disc height increase was about 0.3 mm. During cyclic testing, a gradual decrease in height could be detected due to viscoelastic effects and fluid loss. No gel extrusion could be observed for all specimens during the entire test procedure. A macroscopic inspection after dissections showed an accumulation of the solidified gel in the center of the nucleus. The results demonstrate that the injection of in situ solidifying gels through the intact annulus allows for the stable maintenance of the injected gel at the target location, with high potential for use as a suitable scaffold to anchor therapeutically applied cells for disc regeneration within the treated nucleus pulposus.
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(This article belongs to the Special Issue Hydrogels for the Regeneration of Joints of the Musculoskeletal System in Orthopedics)
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Open AccessArticle
Enhancing the Topical Antibacterial Activity of Fusidic Acid via Embedding into Cinnamon Oil Nano-Lipid Carrier
by
Heba S. Elsewedy, Tamer M. Shehata, Shaymaa M. Genedy, Khuzama M. Siddiq, Bushra Y. Asiri, Rehab A. Alshammari, Sarah I. Bukhari, Adeola T. Kola-Mustapha, Heba A. Ramadan and Wafaa E. Soliman
Gels 2024, 10(4), 268; https://doi.org/10.3390/gels10040268 - 16 Apr 2024
Abstract
Presently, antimicrobial resistance is of great risk to remarkable improvements in health conditions and infection management. Resistance to various antibiotics has been considered a great obstacle in their usage, necessitating alternative strategies for enhancing the antibacterial effect. Combination therapy has been recognized as
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Presently, antimicrobial resistance is of great risk to remarkable improvements in health conditions and infection management. Resistance to various antibiotics has been considered a great obstacle in their usage, necessitating alternative strategies for enhancing the antibacterial effect. Combination therapy has been recognized as a considerable strategy that could improve the therapeutic influence of antibacterial agents. Therefore, the aim of this study was to combine the antibacterial action of compounds of natural origin like fusidic acid (FA) and cinnamon essential oil (CEO) for synergistic effects. A distinctive nanoemulsion (NE) was developed using cinnamon oil loaded with FA. Applying the Box–Behnken design (BBD) approach, one optimized formula was selected and integrated into a gel base to provide an FA-NE-hydrogel for optimal topical application. The FA-NE-hydrogel was examined physically, studied for in vitro release, and investigated for stability upon storage at different conditions, at room (25 °C) and refrigerator (4 °C) temperatures, for up to 3 months. Ultimately, the NE-hydrogel preparation was inspected for its antibacterial behavior using multidrug-resistant bacteria and checked by scanning electron microscopy. The FA-NE-hydrogel formulation demonstrated a pH (6.32), viscosity (12,680 cP), and spreadability (56.7 mm) that are acceptable for topical application. The in vitro release could be extended for 6 h, providing 52.0%. The formulation was stable under both test conditions for up to 3 months of storage. Finally, the FA-NE-hydrogel was found to inhibit the bacterial growth of not only Gram-positive but also Gram-negative bacteria. The inhibition was further elucidated by a scanning electron micrograph, indicating the efficiency of CEO in enhancing the antibacterial influence of FA when combined in an NE system.
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(This article belongs to the Special Issue Designing Gels for Antibacterial and Antiviral Agents)
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Development and Characterization of Thermosensitive and Bioadhesive Ophthalmic Formulations Containing Flurbiprofen Solid Dispersions
by
Pınar Adısanoğlu and Işık Özgüney
Gels 2024, 10(4), 267; https://doi.org/10.3390/gels10040267 - 15 Apr 2024
Abstract
In this study, we aimed to develop thermosensitive and bioadhesive in situ gelling systems containing solid dispersions of flurbiprofen (FB-SDs) using poloxamer 407 (P407) and 188 (P188) for ophthalmic delivery. FB-SDs were prepared with the melt method using P407, characterized by solubility, stability,
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In this study, we aimed to develop thermosensitive and bioadhesive in situ gelling systems containing solid dispersions of flurbiprofen (FB-SDs) using poloxamer 407 (P407) and 188 (P188) for ophthalmic delivery. FB-SDs were prepared with the melt method using P407, characterized by solubility, stability, SEM, DSC, TGA, and XRD analyses. Various formulations of poloxamer mixtures and FB-SDs were prepared using the cold method and P407/P188 (15/26.5%), which gels between 32 and 35 °C, was selected to develop an ophthalmic in situ gelling system. Bioadhesive polymers Carbopol 934P (CP) or carboxymethyl cellulose (CMC) were added in three concentrations (0.2, 0.4, and 0.6% (w/w)). Gelation temperature and time, mechanical properties, flow properties, and viscosity values were determined. The in vitro release rate, release kinetics, and the release mechanism of flurbiprofen (FB) from the ophthalmic formulations were analyzed. The results showed that FB-SDs’ solubility in water increased 332-fold compared with FB. The oscillation study results indicated that increasing bioadhesive polymer concentrations decreased gelation temperature and time, and formulations containing CP gel at lower temperatures and in a shorter time. All formulations except F3 and F4 showed Newtonion flow under non-physiological conditions, while all formulations exhibited non-Newtonion pseudoplastic flow under physiological conditions. Viscosity values increased with an increase in bioadhesive polymer concertation at physiological conditions. Texture profile analysis (TPA) showed that CP-containing formulations had higher hardness, compressibility, and adhesiveness, and the gel structure of formulation F4, containing 0.6% CP, exhibited the greatest hardness, compressibility, and adhesiveness. In vitro drug release studies indicated that CP and CMC had no effect below 0.6% concentration. Kinetic evaluation favored first-order and Hixson–Crowell kinetic models. Release mechanism analysis showed that the n values of the formulations were greater than 1 except for formulation F5, suggesting that FB might be released from the ophthalmic formulations by super case II type diffusion. When all the results of this study are evaluated, the in situ gelling formulations prepared with FB-SDs that contained P407/P188 (15/26.5%) and 0.2% CP or 0.2% CMC or 0.4 CMC% (F2, F5, and F6, respectively) could be promising formulations to prolong precorneal residence time and improve ocular bioavailability of FB.
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(This article belongs to the Special Issue Antibacterial Gels)
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