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
Radiation-Induced Hydrogel for Water Treatment
Gels 2024, 10(6), 375; https://doi.org/10.3390/gels10060375 - 28 May 2024
Abstract
Along with serving as drug delivery sensors and flexible devices, hydrogels are playing pioneering roles in water purification. Both chemical and radiation methods can produce hydrogels, with the latter method gaining preference for its pure adducts. The water treatment process entails the removal
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Along with serving as drug delivery sensors and flexible devices, hydrogels are playing pioneering roles in water purification. Both chemical and radiation methods can produce hydrogels, with the latter method gaining preference for its pure adducts. The water treatment process entails the removal of heavy and toxic metals (above the threshold amount), dyes, and solid wastes from industrial effluents, seawater, and groundwater, as well as sterilization for microorganism destruction. This review analyzed the different types of hydrogels produced by applying various radiations for water treatment. Particularly, we examined the hydrogels created through the application of varying levels of gamma and electron beam radiation from the electron gun and Co-60 sources. Moreover, we discuss the optimized radiation doses, the compositions (monomers and polymers) of raw materials required for hydrogel preparation, and their performance in water purification. We present and predict the current state and future possibilities of radiation-induced hydrogels. We explain and compare the superiority of one radiation method over other radiation methods (UV-visible, X-ray, microwave, etc.) based on water treatment.
Full article
(This article belongs to the Special Issue Gels for Water Treatment)
Open AccessArticle
Improvement of Surimi Gel from Frozen-Stored Silver Carp
by
Jingyi Yang, Xiliang Yu, Xiuping Dong and Chenxu Yu
Gels 2024, 10(6), 374; https://doi.org/10.3390/gels10060374 - 28 May 2024
Abstract
Silver Carp (SC) is an under-utilized, invasive species in North American river systems. In this study, the synergistic effects of manufactured Microfiber (MMF), Transglutaminase (TG), and chicken skin collagen (CLG)) to enhance surimi gel quality from frozen SC were studied. The gel strength,
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Silver Carp (SC) is an under-utilized, invasive species in North American river systems. In this study, the synergistic effects of manufactured Microfiber (MMF), Transglutaminase (TG), and chicken skin collagen (CLG)) to enhance surimi gel quality from frozen SC were studied. The gel strength, textural properties, rheological properties, water-holding capacity (WHC), water mobility, microstructure, and protein composition of the gel samples were determined to assess the impact of the additives individually and synergistically. The results suggested that TG had the most pronounced effect on the surimi gel properties by promoting protein cross-linking. Synergistic effects between TG, MMF, and CLG can bring effective gel property enhancement larger than the individual effect of each additive alone. With the established response-surface models, the combination of CLG and MMF can be optimized to produce surimi gels with less TG but comparable in properties to that of the optimal result with high TG usage. The findings of this study provided a technical foundation for making high-quality surimi gel products out of frozen-stored SC with synergistic utilization of additives, which could serve as guidelines for the industrial development of new surimi products.
Full article
(This article belongs to the Special Issue Recent Advances in Food Gels)
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Open AccessArticle
Enhancing Load-Bearing Capacity of Calcareous Sands through Gel Stabilization: A Mechanical and Material Characterization Study
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Jianxiao Gu, Haibo Lyu, Bo Li, Yong Wang, Hui Chen, Xinyi Gao and Xiaojiang Xu
Gels 2024, 10(6), 373; https://doi.org/10.3390/gels10060373 - 28 May 2024
Abstract
Calcareous sands often display wide ring grain configurations, high intragranular porosity, a complex structure, and low grain hardness. These attributes typically do not meet the strength criteria necessary to sustain overlying infrastructure in civil engineering applications. This study investigates gel stabilization techniques, blending
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Calcareous sands often display wide ring grain configurations, high intragranular porosity, a complex structure, and low grain hardness. These attributes typically do not meet the strength criteria necessary to sustain overlying infrastructure in civil engineering applications. This study investigates gel stabilization techniques, blending gel material with calcareous sand at concentrations ranging from 5% to 22%, followed by curing periods of 3 to 28 days to evaluate the load-bearing capacity. Subsequently, an unconfined compressive test is performed to determine the gel material content in stabilized specimens and investigate the influence of gel material types. The gel material-to-sand ratios employed are set at 5%, 10%, and 16% for Portland cement and 13%, 16%, and 22% for gypsum. After that, a triaxial consolidated undrained test is conducted to assess mechanical behavior, pore water pressure, and mechanical properties. The findings reveal increased dilation, stress–strain hardening, and softening post-yield, regardless of gel material type. Principal stress ratios, secant modulus, and cohesion show a positive correlation with maintenance duration and binder content, with implications for improved load-bearing capacity. The study also elucidates the qualitative relationship between secant modulus E50 and confining pressure.
Full article
(This article belongs to the Special Issue Novel Polymer Gels: Synthesis, Properties, and Applications)
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Open AccessReview
Progress of Research into Preformed Particle Gels for Profile Control and Water Shutoff Techniques
by
Wei Ma, Yikun Li, Pingde Liu, Zhichang Liu and Tao Song
Gels 2024, 10(6), 372; https://doi.org/10.3390/gels10060372 - 28 May 2024
Abstract
Gel treatment is an economical and efficient method of controlling excessive water production. The gelation of in situ gels is prone to being affected by the dilution of formation water, chromatographic during the transportation process, and thus controlling the gelation time and penetration
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Gel treatment is an economical and efficient method of controlling excessive water production. The gelation of in situ gels is prone to being affected by the dilution of formation water, chromatographic during the transportation process, and thus controlling the gelation time and penetration depth is a challenging task. Therefore, a novel gel system termed preformed particle gels (PPGs) has been developed to overcome the drawbacks of in situ gels. PPGs are superabsorbent polymer gels which can swell but not dissolve in brines. Typically, PPGs are a granular gels formed based on the crosslinking of polyacrylamide, characterized by controllable particle size and strength. This work summarizes the application scenarios of PPGs and elucidates their plugging mechanisms. Additionally, several newly developed PPG systems such as high-temperature-resistant PPGs, re-crosslinkable PPGs, and delayed-swelling PPGs are also covered. This research indicates that PPGs can selectively block the formation of fractures or high-permeability channels. The performance of the novel modified PPGs was superior to in situ gels in harsh environments. Lastly, we outlined recommended improvements for the novel PPGs and suggested future research directions.
Full article
(This article belongs to the Special Issue Applications of Gels for Enhanced Oil Recovery)
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Open AccessReview
Hydrogel-Based Interfacial Solar-Driven Evaporation: Essentials and Trails
by
Xiaoyun Hu, Jianfang Yang, Yufei Tu, Zhen Su, Qingqing Guan and Zhiwei Ma
Gels 2024, 10(6), 371; https://doi.org/10.3390/gels10060371 - 27 May 2024
Abstract
Hydrogel-based interfacial solar-driven evaporation (ISDE) gives full play to the highly adjustable physical and chemical properties of hydrogel, which endows ISDE systems with excellent evaporation performance, anti-pollution properties, and mechanical behavior, making it more promising for applications in seawater desalination and wastewater treatment.
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Hydrogel-based interfacial solar-driven evaporation (ISDE) gives full play to the highly adjustable physical and chemical properties of hydrogel, which endows ISDE systems with excellent evaporation performance, anti-pollution properties, and mechanical behavior, making it more promising for applications in seawater desalination and wastewater treatment. This review systematically introduces the latest advances in hydrogel-based ISDE systems from three aspects: the required properties, the preparation methods, and the role played in application scenarios of hydrogels used in ISDE. Additionally, we also discuss the remaining challenges and potential opportunities in hydrogel-based ISDE systems. By summarizing the latest research progress, we hope that researchers in related fields have some insight into the unique advantages of hydrogels in the ISDE field and contribute our efforts so that ISDE technology reaches the finishing line of practical application on the hydrogel track.
Full article
(This article belongs to the Section Gel Analysis and Characterization)
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Open AccessArticle
Development of an Emulgel for the Effective Treatment of Atopic Dermatitis: Biocompatibility and Clinical Investigation
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Almudena Gómez-Farto, Ana Leticia Jiménez-Escobar, Noelia Pérez-González, Herminia Castán, Beatriz Clares, Salvador Arias-Santiago and Trinidad Montero-Vílchez
Gels 2024, 10(6), 370; https://doi.org/10.3390/gels10060370 - 27 May 2024
Abstract
Atopic dermatitis (AD) is a common dermatological disease affecting both children and adults. No drug-free emulgel has been developed and studied in vitro and in vivo for the treatment of AD. The aim of this study was to develop and assess the efficacy
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Atopic dermatitis (AD) is a common dermatological disease affecting both children and adults. No drug-free emulgel has been developed and studied in vitro and in vivo for the treatment of AD. The aim of this study was to develop and assess the efficacy of a topical emulgel containing hyaluronic acid, glycerol, Calendula officinalis, Aloe vera, polyphenols and EGF for the concomitant treatment in patients with AD aged over 14. Objective skin barrier function parameters were included, such as transepidermal water loss (TEWL), skin temperature, pH, stratum corneum hydration, skin elasticity and erythema. The subjective opinion of the patients was determined including acceptability, absorption, comfort of use and tolerability, as well as the degree of improvement in patients’ quality of life. We observed an improvement in the subjective parameters studied and statistically significant differences in the objective parameters. Specifically, we found an improvement in TEWL (p = 0.006), erythema (p = 0.008) and hydration (p < 0.001), parameters indicating an improvement in the epidermal barrier. One hundred per cent of patients were satisfied with the product. Therefore, these results suggest that the product may contribute to the treatment of AD.
Full article
(This article belongs to the Special Issue Gels for Biomedical Applications)
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Open AccessArticle
A Novel Fracturing Fluid Based on Functionally Modified Nano-Silica-Enhanced Hydroxypropyl Guar Gel
by
Feifei Huang, Yun Bai, Xiaoyu Gu, Shaofei Kang, Yandong Yang and Kai Wang
Gels 2024, 10(6), 369; https://doi.org/10.3390/gels10060369 - 27 May 2024
Abstract
Considering the damage caused by conventional fracturing fluid in low-permeability reservoirs, a novel fracturing fluid (FNG) combining hydroxypropyl guar (HPG) and functionally modified nano-silica (FMNS) was prepared. The properties of heat/shear resistance, rheological property, proppant transportation, and formation damage were evaluated with systematic
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Considering the damage caused by conventional fracturing fluid in low-permeability reservoirs, a novel fracturing fluid (FNG) combining hydroxypropyl guar (HPG) and functionally modified nano-silica (FMNS) was prepared. The properties of heat/shear resistance, rheological property, proppant transportation, and formation damage were evaluated with systematic experiments. The results showed that the viscosities of FNG before and after the heat/resistance were 1323 mPa·s and 463 mPa·s, respectively, while that of conventional HPG gel was 350 mPa·s. FNG is a pseudoplastic strong gel with a yield stress of 12.9 Pa, a flow behavior index of 0.54, an elastic modulus of 16.2 Pa, and a viscous modulus of 6.2 Pa. As the proportions of proppant mass in further sections transported with FNG were higher than those transported with HPG gel, FNG could transport the proppant better than HPG gel at high temperatures. Because of the amphiphilic characteristics of FMNS, the surface/interface properties were improved by the FNG filtrate, resulting in a lower oil permeability loss rate of 10 percentage points in the matrix than with the filtrated HPG gel. Due to the considerable residual gel in broken HPG gel, the retained conductivity damaged with broken FNG was 9.5 percentage points higher than that damaged with broken HPG gel. FNG shows good potential for reducing formation damage during fracturing in low-permeability reservoirs in China.
Full article
(This article belongs to the Special Issue Advances in Polymeric Gels and Applications for Hydrocarbon Development and Geologic Carbon Storage)
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Open AccessReview
Agriculture 4.0: Polymer Hydrogels as Delivery Agents of Active Ingredients
by
Aleksandra Mikhailidi, Elena Ungureanu, Bogdan-Marian Tofanica, Ovidiu C. Ungureanu, Maria E. Fortună, Dan Belosinschi and Irina Volf
Gels 2024, 10(6), 368; https://doi.org/10.3390/gels10060368 - 26 May 2024
Abstract
The evolution from conventional to modern agricultural practices, characterized by Agriculture 4.0 principles such as the application of innovative materials, smart water, and nutrition management, addresses the present-day challenges of food supply. In this context, polymer hydrogels have become a promising material for
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The evolution from conventional to modern agricultural practices, characterized by Agriculture 4.0 principles such as the application of innovative materials, smart water, and nutrition management, addresses the present-day challenges of food supply. In this context, polymer hydrogels have become a promising material for enhancing agricultural productivity due to their ability to retain and then release water, which can help alleviate the need for frequent irrigation in dryland environments. Furthermore, the controlled release of fertilizers by the hydrogels decreases chemical overdosing risks and the environmental impact associated with the use of agrochemicals. The potential of polymer hydrogels in sustainable agriculture and farming and their impact on soil quality is revealed by their ability to deliver nutritional and protective active ingredients. Thus, the impact of hydrogels on plant growth, development, and yield was discussed. The question of which hydrogels are more suitable for agriculture—natural or synthetic—is debatable, as both have their merits and drawbacks. An analysis of polymer hydrogel life cycles in terms of their initial material has shown the advantage of bio-based hydrogels, such as cellulose, lignin, starch, alginate, chitosan, and their derivatives and hybrids, aligning with sustainable practices and reducing dependence on non-renewable resources.
Full article
(This article belongs to the Special Issue Hydrogels, Oleogels and Bigels Used for Drug Delivery)
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Rheology of Suspensions of TEMPO-Oxidised and Cationic Cellulose Nanofibrils—The Effect of Chemical Pre-Treatment
by
Luís Alves, Solange Magalhães, Jorge F. S. Pedrosa, Paulo J. T. Ferreira, José A. F. Gamelas and Maria Graça Rasteiro
Gels 2024, 10(6), 367; https://doi.org/10.3390/gels10060367 - 26 May 2024
Abstract
Cellulose nanofibrils (CNFs) are particles with a high aspect ratio. Typically, chemically pre-treated CNFs (containing anionic or cationic charged groups) consist of long fibrils (up to 2 μm) with very low thickness (less than 10 nm). Derived from their high aspect ratio, CNFs
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Cellulose nanofibrils (CNFs) are particles with a high aspect ratio. Typically, chemically pre-treated CNFs (containing anionic or cationic charged groups) consist of long fibrils (up to 2 μm) with very low thickness (less than 10 nm). Derived from their high aspect ratio, CNFs form strong hydrogels with high elasticity at low concentrations. Thus, CNF suspensions appear as an interesting rheology modifier to be applied in cosmetics, paints, foods, and as a mineral suspending agent, among other applications. The high viscosity results from the strong 3D fibril network, which is related to the good fibrillation of the material, allowing the nanofibrils to overlap. The overlap concentration (c*) was found to vary from ca. 0.13 to ca. 0.60 wt.% depending on the type and intensity of the pre-treatment applied during the preparation of the CNFs. The results confirm the higher tendency for the fibres treated with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) and 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) to form a 3D network, resulting in the lowest c*. For the TEMPO-oxidised CNF suspensions, it was also found that aggregation is improved at acidic pH conditions due to lower charge repulsion among fibrils, leading to an increase in the suspension viscosity as well as higher apparent yield stresses. TEMPO CNF suspensions with a low content of carboxylic groups tend to precipitate at moderately acidic pH values.
Full article
(This article belongs to the Special Issue Hydrogel-Based Novel Biomaterials: Achievements and Prospects)
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Open AccessArticle
Formation of Stable Vascular Networks by 3D Coaxial Printing and Schiff-Based Reaction
by
Jingxin Shan, Zhiyuan Kong and Xiaohong Wang
Gels 2024, 10(6), 366; https://doi.org/10.3390/gels10060366 - 25 May 2024
Abstract
Vascularized organs hold potential for various applications, such as organ transplantation, drug screening, and pathological model establishment. Nevertheless, the in vitro construction of such organs encounters many challenges, including the incorporation of intricate vascular networks, the regulation of blood vessel connectivity, and the
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Vascularized organs hold potential for various applications, such as organ transplantation, drug screening, and pathological model establishment. Nevertheless, the in vitro construction of such organs encounters many challenges, including the incorporation of intricate vascular networks, the regulation of blood vessel connectivity, and the degree of endothelialization within the inner cavities. Natural polymeric hydrogels, such as gelatin and alginate, have been widely used in three-dimensional (3D) bioprinting since 2005. However, a significant disparity exists between the mechanical properties of the hydrogel materials and those of human soft tissues, necessitating the enhancement of their mechanical properties through modifications or crosslinking. In this study, we aim to enhance the structural stability of gelatin–alginate hydrogels by crosslinking gelatin molecules with oxidized pullulan (i.e., a polysaccharide) and alginate molecules with calcium chloride (CaCl2). A continuous small-diameter vascular network with an average outer diameter of 1 mm and an endothelialized inner surface is constructed by printing the cell-laden hydrogels as bioinks using a coaxial 3D bioprinter. The findings demonstrate that the single oxidized pullulan crosslinked gelatin and oxidized pullulan/CaCl2 double-crosslinked gelatin–alginate hydrogels both exhibit a superior structural stability compared to their origins and CaCl2 solely crosslinked gelatin–alginate hydrogels. Moreover, the innovative gelatin and gelatin–alginate hydrogels, which have excellent biocompatibilities and very low prices compared with other hydrogels, can be used directly for tissue/organ construction, tissue/organ repairment, and cell/drug transportation.
Full article
(This article belongs to the Special Issue Advances in Biomedical Hydrogels (2nd Edition))
Open AccessReview
Exploring Applications and Preparation Techniques for Cellulose Hydrogels: A Comprehensive Review
by
Yanjin Tang, Zhenxing Fang and Hoo-Jeong Lee
Gels 2024, 10(6), 365; https://doi.org/10.3390/gels10060365 - 25 May 2024
Abstract
Cellulose hydrogels, formed either through physical or chemical cross-linking into a three-dimensional network from cellulose or its derivatives, are renowned for their exceptional water absorption capacities and biocompatibility. Rising demands for sustainable materials have spurred interest in cellulose hydrogels, attributed to their abundant
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Cellulose hydrogels, formed either through physical or chemical cross-linking into a three-dimensional network from cellulose or its derivatives, are renowned for their exceptional water absorption capacities and biocompatibility. Rising demands for sustainable materials have spurred interest in cellulose hydrogels, attributed to their abundant supply, biodegradability, and non-toxic nature. These properties highlight their extensive potential across various sectors including biomedicine, the food industry, and environmental protection. Cellulose hydrogels are particularly advantageous in applications such as drug delivery, wound dressing, and water treatment. Recent large-scale studies have advanced our understanding of cellulose preparation and its applications. This review delves into the fundamental concepts, preparation techniques, and current applications of cellulose hydrogels in diverse fields. It also discusses the latest advances in nano-lignin-based hydrogels, providing a comprehensive overview of this promising material and offering insights and guidance for future research and development.
Full article
(This article belongs to the Special Issue Cellulose- and Nanocellulose-Based Gels: Design and Applications)
Open AccessArticle
PVA Hydrogels Supplemented with PLA Mesh for Tissue Regeneration Scaffold
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Young-Ho Seo, Jae-Man Lee, Sun-Young Park, Myung-Hoo Kim, Seon-Beom Kim and Tae-Hwan Oh
Gels 2024, 10(6), 364; https://doi.org/10.3390/gels10060364 (registering DOI) - 25 May 2024
Abstract
This study examined the tensile strength and biocompatibility properties of polyvinyl alcohol (PVA) hydrogel tissue regeneration scaffolds with polylactic acid (PLA) mesh fabric added as reinforcement, with a focus on the impact of heat treatment temperature and the number of layers of the
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This study examined the tensile strength and biocompatibility properties of polyvinyl alcohol (PVA) hydrogel tissue regeneration scaffolds with polylactic acid (PLA) mesh fabric added as reinforcement, with a focus on the impact of heat treatment temperature and the number of layers of the PLA mesh fabric. The hydrogel scaffolds were prepared using a freeze–thaw method to create PVA hydrogel, with the PLA mesh fabric placed inside the hydrogel. The swelling ratio of the PVA/PLA hydrogel scaffolds decreased with increasing layer number and heat treatment temperature of the PLA mesh. The gel strength was highest when five layers of PLA mesh fabric were added, heat-treated at 120 °C, and confirmed to be properly placed inside the hydrogel by SEM images. The MTT assay and DAPI staining using HaCaT cells demonstrated that the cell proliferation was uninterrupted throughout the experimental period, confirming the biocompatibility of the scaffold. Therefore, we confirmed the possibility of using PLA mesh fabric as a reinforcement for PVA hydrogel to improve the strength of scaffolds for tissue regeneration, and we confirmed the potential of PLA mesh fabric as a reinforcement for various biomaterials.
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(This article belongs to the Special Issue Advances in Hydrogels for Biomedical Applications)
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Antibacterial Silver Nanoparticle Containing Polydopamine Hydrogels That Enhance Re-Epithelization
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Naphtali A. O’Connor, Abdulhaq Syed, Ertan Kastrat and Hai-Ping Cheng
Gels 2024, 10(6), 363; https://doi.org/10.3390/gels10060363 - 24 May 2024
Abstract
A polydopamine polyelectrolyte hydrogel was developed by ionic crosslinking dextran sulfate with a copolymer of polyethyleneimine and polydopamine. Gelation was promoted by the slow hydrolysis of glucono-δ-lactone. Within this hydrogel, silver nanoparticles were generated in situ, ranging from 25 nm to 200 nm
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A polydopamine polyelectrolyte hydrogel was developed by ionic crosslinking dextran sulfate with a copolymer of polyethyleneimine and polydopamine. Gelation was promoted by the slow hydrolysis of glucono-δ-lactone. Within this hydrogel, silver nanoparticles were generated in situ, ranging from 25 nm to 200 nm in size. The antibacterial activity of the hydrogel was proportional to the quantity of silver nanoparticles produced, increasing as the nanoparticle count rose. The hydrogels demonstrated broad-spectrum antibacterial efficacy at concentrations up to 108 cells/mL for P. aeruginosa, K. pneumoniae, E. coli and S. aureus, the four most prevalent bacterial pathogens in chronic septic wounds. In ex vivo studies on human skin, biocompatibility was enhanced by the presence of polydopamine. Dextran sulfate is a known irritant, but formulations with polydopamine showed improved cell viability and reduced levels of the inflammatory biomarkers IL-8 and IL-1α. Silver nanoparticles can inhibit cell migration, but an ex vivo human skin study showed significant re-epithelialization in wounds treated with hydrogels containing silver nanoparticles.
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(This article belongs to the Special Issue Biopolymer-Based Gels for Drug Delivery and Tissue Engineering)
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Nanocomposite Gels Loaded with Flurbiprofen: Characterization and Skin Permeability Assessment in Different Skin Species
by
Sheimah El Bejjaji, Gladys Ramos-Yacasi, Joaquim Suñer-Carbó, Mireia Mallandrich, Lara Goršek, Chandler Quilchez and Ana Cristina Calpena
Gels 2024, 10(6), 362; https://doi.org/10.3390/gels10060362 - 24 May 2024
Abstract
Nanocomposite gels consist of nanoparticles dispersed in a gel matrix. The main aim of this work was to develop nanocomposite gels for topical delivery of Flurbiprofen (FB) for humans and farm animals. Nanocomposite gels were prepared stemming from nanoparticles (NPs) freeze-dried with two
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Nanocomposite gels consist of nanoparticles dispersed in a gel matrix. The main aim of this work was to develop nanocomposite gels for topical delivery of Flurbiprofen (FB) for humans and farm animals. Nanocomposite gels were prepared stemming from nanoparticles (NPs) freeze-dried with two different cryoprotectants, D-(+)-trehalose (NPs-TRE) and polyethylene glycol 3350 (NPs-PEG), sterilized by gamma (γ) irradiation, and gelled with Sepigel® 305. Nanocomposite gels with FB-NPs-TRE and FB-NPs-PEG were physiochemically characterized in terms of appearance, pH, morphological studies, porosity, swelling, degradation, extensibility, and rheological behavior. The drug release profile and kinetics were assessed, as well as, the ex vivo permeation of FB was assessed in human, porcine and bovine skin. In vivo studies in healthy human volunteers were tested without FB to assess the tolerance of the gels with nanoparticles. Physicochemical studies demonstrated the suitability of the gel formulations. The ex vivo skin permeation capacity of FB-NPs nanocomposite gels with different cryoprotectants allowed us to conclude that these formulations are suitable topical delivery systems for human and veterinary medicine. However, there were statistically significant differences in the permeation of each formulation depending on the skin. Results suggested that FB-NPs-PEG nanocomposite gel was most suitable for human and porcine skin, and the FB-NPs-TRE nanocomposite gel was most suitable for bovine skin.
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(This article belongs to the Special Issue Gel-Based Materials for Biomedical Engineering)
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Dual Functionalization of Hyaluronan Dermal Fillers with Vitamin B3: Efficient Combination of Bio-Stimulation Properties with Hydrogel System Resilience Enhancement
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Alexandre Porcello, Michèle Chemali, Cíntia Marques, Corinne Scaletta, Kelly Lourenço, Philippe Abdel-Sayed, Wassim Raffoul, Nathalie Hirt-Burri, Lee Ann Applegate and Alexis Laurent
Gels 2024, 10(6), 361; https://doi.org/10.3390/gels10060361 - 24 May 2024
Abstract
Hyaluronic acid (HA) hydrogels are commonly used for facial dermal filling and for alternative medical aesthetic purposes. High diversity exists in commercial formulations, notably for the optimization of finished product stability, functionality, and performance. Polyvalent ingredients such as calcium hydroxylapatite (CaHA) or vitamin
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Hyaluronic acid (HA) hydrogels are commonly used for facial dermal filling and for alternative medical aesthetic purposes. High diversity exists in commercial formulations, notably for the optimization of finished product stability, functionality, and performance. Polyvalent ingredients such as calcium hydroxylapatite (CaHA) or vitamin B3 (niacinamide) are notably used as bio-stimulants to improve skin quality attributes at the administration site. The aim of the present study was to perform multi-parametric characterization of two novel cross-linked dermal filler formulas (HAR-1 “Instant Refine” and HAR-3 “Maxi Lift”) for elucidation of the various functional impacts of vitamin B3 incorporation. Therefore, the HAR products were firstly comparatively characterized in terms of in vitro rheology, cohesivity, injectability, and resistance to chemical or enzymatic degradation (exposition to H2O2, AAPH, hyaluronidases, or xanthine oxidase). Then, the HAR products were assessed for cytocompatibility and in vitro bio-stimulation attributes in a primary dermal fibroblast model. The results showed enhanced resilience of the cohesive HAR hydrogels as compared to JUVÉDERM® VOLBELLA® and VOLUMA® reference products in a controlled degradation assay panel. Furthermore, significant induction of total collagen synthesis in primary dermal fibroblast cultures was recorded for HAR-1 and HAR-3, denoting intrinsic bio-stimulatory effects comparable or superior to those of the Radiesse® and Sculptra™ reference products. Original results of high translational relevance were generated herein using robust and orthogonal experimental methodologies (hydrogel degradation, functional benchmarking) and study designs. Overall, the reported results confirmed the dual functionalization role of vitamin B3 in cross-linked HA dermal fillers, with a significant enhancement of hydrogel system stability attributes and the deployment of potent bio-stimulatory capacities.
Full article
(This article belongs to the Special Issue Latest Advances and Prospects of Hydrogels for Biomedical Applications)
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Open AccessArticle
Preparation and Testing of Polyethylenimine-Impregnated Silica Gel for CO2 Capture
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Veronika Kyselová, Jakub Havlín and Karel Ciahotný
Gels 2024, 10(6), 360; https://doi.org/10.3390/gels10060360 - 23 May 2024
Abstract
This work studied the low-temperature sorption of carbon dioxide on impregnated silica gel. An impregnating agent was used polyethyleneimine. The content of the impregnating agent in the silica gel matrix was 33.4 wt.%. Material properties such as the Brunauer–Emmett–Teller (BET) surface area, pore
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This work studied the low-temperature sorption of carbon dioxide on impregnated silica gel. An impregnating agent was used polyethyleneimine. The content of the impregnating agent in the silica gel matrix was 33.4 wt.%. Material properties such as the Brunauer–Emmett–Teller (BET) surface area, pore distribution, total pore volume, and thermal stability of the impregnated material were determined for the sample. During the measurement of the adsorption–desorption cycles, the loss of the impregnating agent in the material matrix was also determined. Due to the decrease in the content of polyethyleneimine, the sorption capacity of the adsorbent for CO2 also decreased. It was found that after the 20th adsorption–desorption cycle, the content of the impregnating agent in the adsorbent dropped by 3.15 wt.%, and, as a result, the adsorption capacity for CO2 dropped to almost half.
Full article
(This article belongs to the Special Issue Functionalized Gels for Environmental Applications (2nd Edition))
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Efficacy of Chitosan-Carboxylic Acid Hydrogels in Reducing and Chelating Iron for the Removal of Rust from Stone Surface
by
Francesco Gabriele, Cinzia Casieri and Nicoletta Spreti
Gels 2024, 10(6), 359; https://doi.org/10.3390/gels10060359 - 22 May 2024
Abstract
In the field of stone conservation, the removal of iron stains is one of the most challenging issues due to the stability and low solubility of the ferrous species. In the present paper, three different chitosan-based hydrogels added with acetic, oxalic or citric
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In the field of stone conservation, the removal of iron stains is one of the most challenging issues due to the stability and low solubility of the ferrous species. In the present paper, three different chitosan-based hydrogels added with acetic, oxalic or citric acids are applied on different lithotypes, i.e., granite, travertine and marble, widely diffused in monumental heritages, and artificially stained by deposition of a rust dispersion. The reducing power of carboxylic acids is combined with the good chelating properties of chitosan to effectively remove rust from stone surfaces. As evidenced by colorimetry on three samples of each lithotype and confirmed by 1H-NMR relaxometry and SEM/EDS analyses, the chitosan-oxalic acid hydrogel shows the best performance and a single application of 24 h is enough to get a good restoration of the stone original features. Lastly, the chitosan-oxalic acid hydrogel performs well when a rusted iron grid is placed directly on the lithic surfaces to simulate a more realistic pollution. Current work in progress is devoted to finding better formulations for marble, which is the most challenging to clean or, with a different approach, to developing protective agents to prevent rust deposition.
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(This article belongs to the Special Issue Gels for Removal and Adsorption (2nd Edition))
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TiO2–Alginate–Chitosan-Based Composites for Skin Tissue Engineering Applications
by
Emma Bobu, Kata Saszet, Zsejke-Réka Tóth, Emőke Páll, Tamás Gyulavári, Lucian Baia, Klara Magyari and Monica Baia
Gels 2024, 10(6), 358; https://doi.org/10.3390/gels10060358 - 22 May 2024
Abstract
The UV-B component of sunlight damages the DNA in skin cells, which can lead to skin cancer and premature aging. Therefore, it is necessary to use creams that also contain UV-active substances. Many sunscreens contain titanium dioxide due to its capacity to absorb
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The UV-B component of sunlight damages the DNA in skin cells, which can lead to skin cancer and premature aging. Therefore, it is necessary to use creams that also contain UV-active substances. Many sunscreens contain titanium dioxide due to its capacity to absorb UV-B wavelengths. In the present study, titan dioxide was introduced in alginate and chitosan–alginate hydrogel composites that are often involved as scaffold compositions in tissue engineering applications. Alginate and chitosan were chosen due to their important role in skin regeneration and skin protection. The composites were cross-linked with calcium ions and investigated using FT-IR, Raman, and UV–Vis spectroscopy. The stability of the obtained samples under solar irradiation for skin protection and regeneration was analyzed. Then, the hydrogel composites were assayed in vitro by immersing them in simulated body fluid and exposing them to solar simulator radiation for 10 min. The samples were found to be stable under solar light, and a thin apatite layer covered the surface of the sample with the two biopolymers and titanium dioxide. The in vitro cell viability assay suggested that the anatase phase in alginate and chitosan–alginate hydrogel composites have a positive impact.
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(This article belongs to the Special Issue Advances in Chitin- and Chitosan-Based Hydrogels)
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Effect of Gold Nanoparticle Size on Regulated Catalytic Activity of Temperature-Responsive Polymer−Gold Nanoparticle Hybrid Microgels
by
Palida Pongsanon, Akifumi Kawamura, Hideya Kawasaki and Takashi Miyata
Gels 2024, 10(6), 357; https://doi.org/10.3390/gels10060357 - 22 May 2024
Abstract
Gold nanoparticles (AuNPs) possess attractive electronic, optical, and catalytic properties, enabling many potential applications. Poly(N-isopropyl acrylamide) (PNIPAAm) is a temperature-responsive polymer that changes its hydrophilicity upon a slight temperature change, and combining PNIPAAm with AuNPs allows us to modulate the properties
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Gold nanoparticles (AuNPs) possess attractive electronic, optical, and catalytic properties, enabling many potential applications. Poly(N-isopropyl acrylamide) (PNIPAAm) is a temperature-responsive polymer that changes its hydrophilicity upon a slight temperature change, and combining PNIPAAm with AuNPs allows us to modulate the properties of AuNPs by temperature. In a previous study, we proposed a simpler method for designing PNIPAAm–AuNP hybrid microgels, which used an AuNP monomer with polymerizable groups. The size of AuNPs is the most important factor influencing their catalytic performance, and numerous studies have emphasized the importance of controlling the size of AuNPs by adjusting their stabilizer concentration. This paper focuses on the effect of AuNP size on the catalytic activity of PNIPAAm–AuNP hybrid microgels prepared via the copolymerization of N-isopropyl acrylamide and AuNP monomers with different AuNP sizes. To quantitatively evaluate the catalytic activity of the hybrid microgels, we monitored the reduction of 4-nitrophenol to 4-aminophenol using the hybrid microgels with various AuNP sizes. While the hybrid microgels with an AuNP size of 13.0 nm exhibited the highest reaction rate and the apparent reaction rate constant (kapp) of 24.2 × 10−3 s−1, those of 35.9 nm exhibited a small kapp of 1.3 × 10−3 s−1. Thus, the catalytic activity of the PNIPAAm–AuNP hybrid microgel was strongly influenced by the AuNP size. The hybrid microgels with various AuNP sizes enabled the reversibly temperature-responsive on–off regulation of the reduction reaction.
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(This article belongs to the Special Issue Recent Advances in Smart Gels)
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Composite Hydrogel with Oleic Acid-Grafted Mesoporous Silica Nanoparticles for Enhanced Topical Delivery of Doxorubicin
by
Marta Slavkova, Diana Dimitrova, Christina Voycheva, Teodora Popova, Ivanka Spassova, Daniela Kovacheva, Yordan Yordanov, Virginia Tzankova and Borislav Tzankov
Gels 2024, 10(6), 356; https://doi.org/10.3390/gels10060356 - 22 May 2024
Abstract
Mesoporous silica nanoparticles (MSNs) are inorganic nanocarriers presenting versatile properties and the possibility to deliver drug molecules via different routes of application. Their modification with lipids could diminish the burst release profile for water-soluble molecules. In the case of oleic acid (OA) as
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Mesoporous silica nanoparticles (MSNs) are inorganic nanocarriers presenting versatile properties and the possibility to deliver drug molecules via different routes of application. Their modification with lipids could diminish the burst release profile for water-soluble molecules. In the case of oleic acid (OA) as a lipid component, an improvement in skin penetration can be expected. Therefore, in the present study, aminopropyl-functionalized MSNs were modified with oleic acid through carbodiimide chemistry and were subsequently incorporated into a semisolid hydrogel for dermal delivery. Doxorubicin served as a model drug. The FT-IR and XRD analysis as well as the ninhydrin reaction showed the successful preparation of the proposed nanocarrier with a uniform particle size (352–449 nm) and negative zeta potential. Transmission electron microscopy was applied to evaluate any possible changes in morphology. High encapsulation efficiency (97.6 ± 1.8%) was achieved together with a sustained release profile over 48 h. The composite hydrogels containing the OA-modified nanoparticles were characterized by excellent physiochemical properties (pH of 6.9; occlusion factor of 53.9; spreadability of factor 2.87 and viscosity of 1486 Pa·s) for dermal application. The in vitro permeation study showed 2.35 fold improvement compared with the hydrogel containing free drug. In vitro cell studies showed that loading in OA-modified nanoparticles significantly improved doxorubicin’s cytotoxic effects toward epidermoid carcinoma cells (A431). All of the results suggest that the prepared composite hydrogel has potential for dermal delivery of doxorubicin in the treatment of skin cancer.
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(This article belongs to the Special Issue Recent Advances in Hydrogels for Biomedical Application)
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