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Gels, Volume 10, Issue 6 (June 2024) – 57 articles

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20 pages, 2462 KiB  
Article
Impact of Hydroxyapatite on Gelatin/Oxidized Alginate 3D-Printed Cryogel Scaffolds
by Ainur Zhanbassynova, Fariza Mukasheva, Madi Abilev, Dmitriy Berillo, Alexander Trifonov and Dana Akilbekova
Gels 2024, 10(6), 406; https://doi.org/10.3390/gels10060406 (registering DOI) - 18 Jun 2024
Viewed by 1
Abstract
Fabrication of scaffolds via 3D printing is a promising approach for tissue engineering. In this study, we combined 3D printing with cryogenic crosslinking to create biocompatible gelatin/oxidized alginate (Gel/OxAlg) scaffolds with large pore sizes, beneficial for bone tissue regeneration. To enhance the osteogenic [...] Read more.
Fabrication of scaffolds via 3D printing is a promising approach for tissue engineering. In this study, we combined 3D printing with cryogenic crosslinking to create biocompatible gelatin/oxidized alginate (Gel/OxAlg) scaffolds with large pore sizes, beneficial for bone tissue regeneration. To enhance the osteogenic effects and mechanical properties of these scaffolds, we evaluated the impact of hydroxyapatite (HAp) on the rheological characteristics of the 2.86% (1:1) Gel/OxAlg ink. We investigated the morphological and mechanical properties of scaffolds with low, 5%, and high 10% HAp content, as well as the resulting bio- and osteogenic effects. Scanning electron microscopy revealed a reduction in pore sizes from 160 to 180 µm (HAp-free) and from 120 to 140 µm for both HAp-containing scaffolds. Increased stability and higher Young’s moduli were measured for 5% and 10% HAp (18 and 21 kPa, respectively) compared to 11 kPa for HAp-free constructs. Biological assessments with mesenchymal stem cells indicated excellent cytocompatibility and osteogenic differentiation in all scaffolds, with high degree of mineralization in HAp-containing constructs. Scaffolds with 5% HAp exhibited improved mechanical characteristics and shape fidelity, demonstrated positive osteogenic impact, and enhanced bone tissue formation. Increasing the HAp content to 10% did not show any advantages in osteogenesis, offering a minor increase in mechanical strength at the cost of significantly compromised shape fidelity. Full article
16 pages, 19173 KiB  
Article
Synthesis and Characterization of Nanocomposite Hydrogels Based on Poly(Sodium 4-Styrene Sulfonate) under Very-High Concentration Regimen of Clays (Bentonite and Kaolinite)
by Tulio A. Lerma, Enrique M. Combatt and Manuel Palencia
Gels 2024, 10(6), 405; https://doi.org/10.3390/gels10060405 (registering DOI) - 18 Jun 2024
Viewed by 105
Abstract
The aim of this work was to synthesize and study the functional properties of polymer-clay nanocomposite (PCNCs) based on poly(sodium 4-styrene sulfonate) (NaPSS) and two types of clay in the dispersed phase: bentonite and kaolinite, in order to advance in the development of [...] Read more.
The aim of this work was to synthesize and study the functional properties of polymer-clay nanocomposite (PCNCs) based on poly(sodium 4-styrene sulfonate) (NaPSS) and two types of clay in the dispersed phase: bentonite and kaolinite, in order to advance in the development of new geomimetic materials for agricultural and environmental applications. In this study, the effect of adding high concentrations of clay (10–20 wt. %) on the structural and functional properties of a polymer–clay nanocomposite was evaluated. The characterization by infrared spectroscopy made it possible to show that the PCNCs had a hybrid nature structure through the identification of typical vibration bands of the clay matrix and NaPSS. In addition, scanning electron microscopy allowed us to verify its hybrid composition and an amorphous particle-like morphology. The thermal characterization showed degradation temperatures higher than ~300 °C with Tg values higher than 100 °C and variables depending on the clay contents. In addition, the PCNCs showed a high water-retention capacity (>2900%) and cation exchange capacity (>112 meq/100 g). Finally, the results demonstrated the ability of geomimetic conditioners to mimic the structure and functional properties of soils, suggesting their potential application in improving soil quality for plant growth. Full article
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18 pages, 2867 KiB  
Review
Advances in Hydrogels of Drug Delivery Systems for the Local Treatment of Brain Tumors
by Jingru Yang, Zhijie Wang, Chenyan Ma, Hongyu Tang, Haoyang Hao, Mengyao Li, Xianwei Luo, Mingxin Yang, Liang Gao and Juan Li
Gels 2024, 10(6), 404; https://doi.org/10.3390/gels10060404 - 17 Jun 2024
Viewed by 261
Abstract
The management of brain tumors presents numerous challenges, despite the employment of multimodal therapies including surgical intervention, radiotherapy, chemotherapy, and immunotherapy. Owing to the distinct location of brain tumors and the presence of the blood–brain barrier (BBB), these tumors exhibit considerable heterogeneity and [...] Read more.
The management of brain tumors presents numerous challenges, despite the employment of multimodal therapies including surgical intervention, radiotherapy, chemotherapy, and immunotherapy. Owing to the distinct location of brain tumors and the presence of the blood–brain barrier (BBB), these tumors exhibit considerable heterogeneity and invasiveness at the histological level. Recent advancements in hydrogel research for the local treatment of brain tumors have sought to overcome the primary challenge of delivering therapeutics past the BBB, thereby ensuring efficient accumulation within brain tumor tissues. This article elaborates on various hydrogel-based delivery vectors, examining their efficacy in the local treatment of brain tumors. Additionally, it reviews the fundamental principles involved in designing intelligent hydrogels that can circumvent the BBB and penetrate larger tumor areas, thereby facilitating precise, controlled drug release. Hydrogel-based drug delivery systems (DDSs) are posited to offer a groundbreaking approach to addressing the challenges and limitations inherent in traditional oncological therapies, which are significantly impeded by the unique structural and pathological characteristics of brain tumors. Full article
(This article belongs to the Special Issue Advanced Hydrogels for Controlled Drug Delivery (2nd Edition))
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26 pages, 1731 KiB  
Review
The Application Potential of Artificial Intelligence and Numerical Simulation in the Research and Formulation Design of Drilling Fluid Gel Performance
by Keming Sheng, Yinbo He, Mingliang Du and Guancheng Jiang
Gels 2024, 10(6), 403; https://doi.org/10.3390/gels10060403 - 17 Jun 2024
Viewed by 227
Abstract
Drilling fluid is pivotal for efficient drilling. However, the gelation performance of drilling fluids is influenced by various complex factors, and traditional methods are inefficient and costly. Artificial intelligence and numerical simulation technologies have become transformative tools in various disciplines. This work reviews [...] Read more.
Drilling fluid is pivotal for efficient drilling. However, the gelation performance of drilling fluids is influenced by various complex factors, and traditional methods are inefficient and costly. Artificial intelligence and numerical simulation technologies have become transformative tools in various disciplines. This work reviews the application of four artificial intelligence techniques—expert systems, artificial neural networks (ANNs), support vector machines (SVMs), and genetic algorithms—and three numerical simulation techniques—computational fluid dynamics (CFD) simulations, molecular dynamics (MD) simulations, and Monte Carlo simulations—in drilling fluid design and performance optimization. It analyzes the current issues in these studies, pointing out that challenges in applying these two technologies to drilling fluid gelation performance research include difficulties in obtaining field data and overly idealized model assumptions. From the literature review, it can be estimated that 52.0% of the papers are related to ANNs. Leakage issues are the primary concern for practitioners studying drilling fluid gelation performance, accounting for over 17% of research in this area. Based on this, and in conjunction with the technical requirements of drilling fluids and the development needs of drilling intelligence theory, three development directions are proposed: (1) Emphasize feature engineering and data preprocessing to explore the application potential of interpretable artificial intelligence. (2) Establish channels for open access to data or large-scale oil and gas field databases. (3) Conduct in-depth numerical simulation research focusing on the microscopic details of the spatial network structure of drilling fluids, reducing or even eliminating data dependence. Full article
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22 pages, 7021 KiB  
Article
Impact of Fibrin Gel Architecture on Hepatocyte Growth Factor Release and Its Role in Modulating Cell Behavior for Tissue Regeneration
by Svenja Wein, Shannon Anna Jung, Miriam Aischa Al Enezy-Ulbrich, Luca Reicher, Stephan Rütten, Mark Kühnel, Danny Jonigk, Wilhelm Jahnen-Dechent, Andrij Pich and Sabine Neuss
Gels 2024, 10(6), 402; https://doi.org/10.3390/gels10060402 - 16 Jun 2024
Viewed by 209
Abstract
A novel scaffold design has been created to enhance tissue engineering and regenerative medicine by optimizing the controlled, prolonged release of Hepatocyte Growth Factor (HGF), a powerful chemoattractant for endogenous mesenchymal stem cells. We present a new stacked scaffold that is made up [...] Read more.
A novel scaffold design has been created to enhance tissue engineering and regenerative medicine by optimizing the controlled, prolonged release of Hepatocyte Growth Factor (HGF), a powerful chemoattractant for endogenous mesenchymal stem cells. We present a new stacked scaffold that is made up of three different fibrin gel layers, each of which has HGF integrated into the matrix. The design attempts to preserve HGF’s regenerative properties for long periods of time, which is necessary for complex tissue regeneration. These multi-layered fibrin gels have been mechanically evaluated using rheometry, and their degradation behavior has been studied using D-Dimer ELISA. Understanding the kinetics of HGF release from this novel scaffold configuration is essential for understanding HGF’s long-term sustained bioactivity. A range of cell-based tests were carried out to verify the functionality of HGF following extended incorporation. These tests included 2-photon microscopy using phalloidin staining to examine cellular morphology, SEM analysis for scaffold–cell interactions, and scratch and scatter assays to assess migration and motility. The analyses show that the novel stacking scaffold promotes vital cellular processes for tissue regeneration in addition to supporting HGF’s bioactivity. This scaffold design was developed for in situ tissue engineering. Using the body as a bioreactor, the scaffold should recruit mesenchymal stem cells from their niche, thus combining the regenerative abilities of HGF and MSCs to promote tissue remodeling and wound repair. Full article
(This article belongs to the Special Issue Hydrogel for Tissue Regeneration)
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18 pages, 2630 KiB  
Article
Binary Pea Protein–Psyllium Hydrogel: Insights into the Influence of pH and Ionic Strength on the Physical Stability and Mechanical Characteristics
by Adonis Hilal, Anna Florowska, Ewa Domian and Małgorzata Wroniak
Gels 2024, 10(6), 401; https://doi.org/10.3390/gels10060401 - 16 Jun 2024
Viewed by 340
Abstract
Food hydrogels, used as delivery systems for bioactive compounds, can be formulated with various food-grade biopolymers. Their industrial utility is largely determined by their physicochemical properties. However, comprehensive data on the properties of pea protein–psyllium binary hydrogels under different pH and ionic strength [...] Read more.
Food hydrogels, used as delivery systems for bioactive compounds, can be formulated with various food-grade biopolymers. Their industrial utility is largely determined by their physicochemical properties. However, comprehensive data on the properties of pea protein–psyllium binary hydrogels under different pH and ionic strength conditions are limited. The aim of this research was to evaluate the impact of pH (adjusted to 7, 4.5, and 3) and ionic strength (modified by NaCl addition to 0.15 and 0.3 M) on the physical stability, color, texture, microrheological, and viscoelastic properties of these hydrogels. Color differences were most noticeable at lower pH levels. Inducing hydrogels at pH 7 (with or without NaCl) and pH 4.5 and 3 (without NaCl) resulted in complete gel structures with low stability, low elastic and storage moduli, and low complex viscosity, making them easily spreadable. Lower pH inductions (4.5 and 3) in the absence of NaCl resulted in hydrogels with shorter linear viscoelastic regions. Hydrogels induced at pH 4.5 and 3 with NaCl had high structural stability, high G’ and G” moduli, complex viscosity, and high spreadability. Among the tested induction conditions, pH 3 with 0.3 M NaCl allowed for obtaining a hydrogel with the highest elastic and storage moduli values. Adjusting pH and ionic strength during hydrogel induction allows for modifying and tailoring their properties for specific industrial applications. Full article
(This article belongs to the Special Issue Recent Advances in Protein Gels)
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23 pages, 13481 KiB  
Review
Advances in Carbon Xerogels: Structural Optimization for Enhanced EDLC Performance
by Jongyun Choi, Ji Chul Jung and Wonjong Jung
Gels 2024, 10(6), 400; https://doi.org/10.3390/gels10060400 - 14 Jun 2024
Viewed by 456
Abstract
This review explores the recent progress on carbon xerogels (CXs) and highlights their development and use as efficient electrodes in organic electric double-layer capacitors (EDLCs). In addition, this work examines how the adjustment of synthesis parameters, such as pH, polymerization duration, and the [...] Read more.
This review explores the recent progress on carbon xerogels (CXs) and highlights their development and use as efficient electrodes in organic electric double-layer capacitors (EDLCs). In addition, this work examines how the adjustment of synthesis parameters, such as pH, polymerization duration, and the reactant-to-catalyst ratio, crucially affects the structure and electrochemical properties of xerogels. The adaptability of xerogels in terms of modification of their porosity and structure plays a vital role in the improvement of EDLC applications as it directly influences the interaction between electrolyte ions and the electrode surface, which is a key factor in determining EDLC performance. The review further discusses the substantial effects of chemical activation with KOH on the improvement of the porous structure and specific surface area, which leads to notable electrochemical enhancements. This structural control facilitates improvement in ion transport and storage, which are essential for efficient EDLC charge–discharge (C–D) cycles. Compared with commercial activated carbons for EDLC electrodes, CXs attract interest for their superior surface area, lower electrical resistance, and stable performance across diverse C–D rates, which underscore their promising potential in EDLC applications. This in-depth review not only summarizes the advancements in CX research but also highlights their potential to expand and improve EDLC applications and demonstrate the critical role of their tunable porosity and structure in the evolution of next-generation energy storage systems. Full article
(This article belongs to the Special Issue Research Progress and Application Prospects of Gel Electrolytes)
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17 pages, 1060 KiB  
Article
Candelilla Wax and Glycerol Monostearate-Based Oleogels as Animal Fat Substitutes in Bologna Sausages
by Anda Elena Tanislav, Anca Alexandra Cornea, Eugen Dan Radu, Dorin Țibulcă, Vlad Mureșan and Elena Mudura
Gels 2024, 10(6), 399; https://doi.org/10.3390/gels10060399 - 13 Jun 2024
Viewed by 413
Abstract
The aim of this study was to produce Bologna sausages rich in unsaturated fatty acids and to evaluate this replacement on the structural characteristics. For the purpose of a comparative analysis, three different types of sausages were produced, distinct only in the type [...] Read more.
The aim of this study was to produce Bologna sausages rich in unsaturated fatty acids and to evaluate this replacement on the structural characteristics. For the purpose of a comparative analysis, three different types of sausages were produced, distinct only in the type of fat used: I. sausages obtained with pork backfat (PBF), II. sausages produced with oleogel formed from refined sunflower oil and glycerol monostearate (GM_OG), and III. with candelilla wax oleogel (CW_OG). The meat composition was also analyzed to better understand the process in the dynamics and the finished products were analyzed both uncooked and cooked. The enhanced oil-binding capacity of oleogels suggests their potential value as substitutes for saturated fats (>99%). In terms of meat composition textural analysis, the highest hardness value was registered for PBF_C of 25.23 N, followed by a CW_OG_C of 13.08 N and a GM_OG_C of 12.27 N. However, adhesiveness, cohesiveness, springiness index, and gumminess showed similar values between samples. Reformulation of products with oleogels as a fat source abundant in mono- and polyunsaturated fatty acids resulted in uncooked products exhibiting reduced hardness values of 49.01 N (CW_OG_US) and 40.51 N (GM_OG_US), compared to 65.03 N (PBF_US). Color results of the cross-section color can indicate the potential for consumer acceptance due to the reduced color differences between the conventional and oleogel samples. Full article
(This article belongs to the Special Issue Recent Advances in Oil Structuring)
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16 pages, 7330 KiB  
Article
The Highly Durable Antibacterial Gel-like Coatings for Textiles
by Seyedali Mirmohammadsadeghi, David Juhas, Mikhail Parker, Kristina Peranidze, Dwight Austin Van Horn, Aayushi Sharma, Dhruvi Patel, Tatyana A. Sysoeva, Vladislav Klepov and Vladimir Reukov
Gels 2024, 10(6), 398; https://doi.org/10.3390/gels10060398 - 13 Jun 2024
Viewed by 328
Abstract
Hospital-acquired infections are considered a priority for public health systems since they pose a significant burden for society. High-touch surfaces of healthcare centers, including textiles, provide a suitable environment for pathogenic bacteria to grow, necessitating incorporating effective antibacterial agents into textiles. This paper [...] Read more.
Hospital-acquired infections are considered a priority for public health systems since they pose a significant burden for society. High-touch surfaces of healthcare centers, including textiles, provide a suitable environment for pathogenic bacteria to grow, necessitating incorporating effective antibacterial agents into textiles. This paper introduces a highly durable antibacterial gel-like solution, Silver Shell™ finish, which contains chitosan-bound silver chloride microparticles. The study investigates the coating’s environmental impact, health risks, and durability during repeated washing. The structure of the Silver Shell™ finish was studied using transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The TEM images showed a core–shell structure, with chitosan forming a protective shell around groupings of silver microparticles. The field-emission scanning electron microscopy (FESEM) demonstrated the uniform deposition of Silver Shell™ on the surfaces of the fabrics. AATCC Test Method 100 was employed to quantitatively analyze the antibacterial properties of the fabrics coated with silver microparticles. Two types of bacteria, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), were used in this study. The antibacterial results showed that after 75 wash cycles, a 100% reduction for both S. aureus and E. coli in the coated samples using crosslinking agents was observed. The coated samples without a crosslinking agent exhibited 99.88% and 99.81% reductions for S. aureus and E. coli after 50 washing cycles. To compare the antibacterial properties toward non-pathogenic and pathogenic strains of the same species, MG1655 model E. coli strain (ATCC 29213) and a multidrug-resistant clinical isolate were used. The results showed the antibacterial efficiency of the Silver ShellTM solution (up to 99.99% reduction) coated on cotton fabric. AATCC-147 was performed to investigate the coated samples’ leaching properties and the crosslinking agent’s effects against S. aureus and E. coli. All coated samples demonstrated remarkable antibacterial efficacy, even after 75 wash cycles. The crosslinking agent facilitated durable attachment between the silver microparticles and cotton substrate, minimizing the release of particles from the fabrics. Color measurements were conducted to assess the color differences resulting from the coating process. The results indicated fixation values of 44%, 32%, and 28% following 25, 50, and 75 washing cycles, respectively. Full article
(This article belongs to the Special Issue Functional Gels Applied in Tissue Engineering)
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17 pages, 1713 KiB  
Article
Development and Characterization of New Plant-Based Ice Cream Assortments Using Oleogels as Fat Source
by Sorina Ropciuc, Cristina Ghinea, Ana Leahu, Ancuta Elena Prisacaru, Mircea Adrian Oroian, Laura Carmen Apostol and Florina Dranca
Gels 2024, 10(6), 397; https://doi.org/10.3390/gels10060397 - 12 Jun 2024
Viewed by 184
Abstract
The objective of this study was to develop candelilla wax oleogels with hemp seed oil and olive oil and use them as a fat source in the development of new plant-based ice cream assortments. Oleogels were structured with 3 and 9% candelilla wax [...] Read more.
The objective of this study was to develop candelilla wax oleogels with hemp seed oil and olive oil and use them as a fat source in the development of new plant-based ice cream assortments. Oleogels were structured with 3 and 9% candelilla wax and characterized by oil-binding capacity, peroxide value and color parameters. The oil-binding capacities of 9% wax oleogels were significantly higher than those of 3% wax oleogels, while peroxide values of oleogels decrease with increasing wax dosage. All oleogel samples are yellow-green due to the pigments present in the oils and candelilla wax. Physicochemical (pH, titratable acidity, soluble solids, fat, protein) and rheological (viscosity and viscoelastic modulus) parameters of plant-based ice cream mixes with oleogels were determined. Also, sensory attributes and texture parameters were investigated. The results showed that titratable acidity and fat content of plant-based ice cream samples increased with increasing wax percentage, while pH, soluble solids and protein values are more influenced by the type of plant milk used. The plant-based ice cream sample with spelt milk, hemp oil and 9% candelilla wax received the highest overall acceptability score. The hardness of the plant-based ice cream samples increased as the percentage of candelilla wax added increased. Full article
13 pages, 2231 KiB  
Article
Short-Term Effects of Two COX-2 Selective Non-Steroidal Anti-Inflammatory Drugs on the Release of Growth Factors and Cytokines from Canine Platelet-Rich Gel Supernatants
by Julián Ospina, Jorge U. Carmona and Catalina López
Gels 2024, 10(6), 396; https://doi.org/10.3390/gels10060396 - 12 Jun 2024
Viewed by 306
Abstract
(1) Background: There is a lack of knowledge about how a single dose of COX-2 selective non-steroidal anti-inflammatory drugs (NSAIDs) might affect the release of growth factors (GFs) and cytokines from canine platelet-rich gels (PRGs) and other hemocomponents. (2) Methods: A crossover study [...] Read more.
(1) Background: There is a lack of knowledge about how a single dose of COX-2 selective non-steroidal anti-inflammatory drugs (NSAIDs) might affect the release of growth factors (GFs) and cytokines from canine platelet-rich gels (PRGs) and other hemocomponents. (2) Methods: A crossover study was conducted in six adult mongrel dogs. Animals were randomized to receive a single dose of either carprofen or firocoxib. PRG, temperature-induced platelet lysate (TIPL), chemically induced PL (CIPL), and plasma hemocomponents were obtained from each dog before (1 h) and after (6 h) the treatments. Platelet and leukocyte counts and determination of the concentrations of platelet-derived growth factor-BB, (PDGF-BB), transforming growth factor beta-1 (TGF-β1), interleukin 1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α) and IL-10 concentrations were assayed by ELISA in all hemocomponents. (3) Results: Both platelet and leukocyte counts and PDGF-BB concentrations were not affected by NSAIDs and time. Total TGF-β1 concentrations were not affected by NSAIDs; however, the release of this GF was increased in PRG supernatants (PRGS) at 6 h. IL-1β and TNF-α concentrations were significantly (p < 0.001) lower in both firocoxib PRGS and plasma at 6 h, respectively. IL-10 concentrations were significantly (p < 0.001) lower at 6 h in all hemocomponents treated with both NSAIDs. (4) Conclusions: The clinical implications of our findings could indicate that these drugs should be withdrawn from patients to allow their clearance before the clinical use of PRP/PRG. On the other hand, the prophylactic use of NSAIDs to avoid the inflammatory reactions that some patients might have after PRP/PRG treatment should be performed only in those animals with severe reactive inflammation to the treatment. Full article
(This article belongs to the Special Issue Synthesis, Characterization and Pharmaceutical Applications of Gels)
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27 pages, 4006 KiB  
Article
The Method of Direct and Reverse Phase Portraits as a Tool for Systematizing the Results of Studies of Phase Transitions in Solutions of Thermosensitive Polymers
by Akhat Bakirov, Eldar Kopishev, Kaisarali Kadyrzhan, Elvira Donbaeva, Aigerim Zhaxybayeva, Marat Duisembiyev, Faiziya Suyundikova and Ibragim Suleimenov
Gels 2024, 10(6), 395; https://doi.org/10.3390/gels10060395 - 11 Jun 2024
Viewed by 359
Abstract
It is shown that a more than significant amount of experimental data obtained in the field of studying systems based on thermosensitive hydrophilic polymers and reflected in the literature over the past decades makes the issue of their systematization and classification relevant. This, [...] Read more.
It is shown that a more than significant amount of experimental data obtained in the field of studying systems based on thermosensitive hydrophilic polymers and reflected in the literature over the past decades makes the issue of their systematization and classification relevant. This, in turn, makes relevant the question of choosing the appropriate classification criteria. It is shown that the basic classification feature can be the number of phase transition stages, which can vary from one to four or more depending on the nature of the temperature-sensitive system. In this work, the method of inverse phase portraits is proposed for the first time. It was intended, among other things, to identify the number of phase transition stages. Moreover, the accuracy of this method significantly exceeds the accuracy of the previously used method of direct phase portraits since, for the first time, the operation of numerical differentiation is replaced by the operation of numerical integration. A specific example of the application of the proposed method for the analysis of a previously studied temperature-sensitive system is presented. It is shown that this method also allows for a quantitative comparison between the results obtained by the differential calorimetry method and the turbidimetry method. Issues related to increasing the resolution of the method of direct phase portraits are discussed. Full article
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13 pages, 6302 KiB  
Article
Fabrication and Advanced Imaging Characterization of Magnetic Aerogel-Based Thin Films for Water Decontamination
by Adelina-Gabriela Niculescu, Bogdan Mihaiescu, Alexandra Cătălina Bîrcă, Alina Moroșan, Oana Maria Munteanu (Mihaiescu), Bogdan Ștefan Vasile, Tony Hadibarata, Daniela Istrati, Dan Eduard Mihaiescu and Alexandru Mihai Grumezescu
Gels 2024, 10(6), 394; https://doi.org/10.3390/gels10060394 - 11 Jun 2024
Viewed by 318
Abstract
Aerogels have emerged as appealing materials for various applications due to their unique features, such as low density, high porosity, high surface area, and low thermal conductivity. Aiming to bring the advantages of these materials to the environmental field, this study focuses on [...] Read more.
Aerogels have emerged as appealing materials for various applications due to their unique features, such as low density, high porosity, high surface area, and low thermal conductivity. Aiming to bring the advantages of these materials to the environmental field, this study focuses on synthesizing magnetic silica aerogel-based films suitable for water decontamination. In this respect, a novel microfluidic platform was created to obtain core-shell iron oxide nanoparticles that were further incorporated into gel-forming precursor solutions. Afterward, dip-coating deposition was utilized to create thin layers of silica-based gels, which were further processed by 15-hour gelation time, solvent transfer, and further CO2 desiccation. A series of physicochemical analyses (XRD, HR-MS FT-ICR, FT-IR, TEM, SEM, and EDS) were performed to characterize the final films and intermediate products. The proposed advanced imaging experimental model for film homogeneity and adsorption characteristics confirmed uniform aerogel film deposition, nanostructured surface, and ability to remove pesticides from contaminated water samples. Based on thorough investigations, it was concluded that the fabricated magnetic aerogel-based thin films are promising candidates for water decontamination and novel solid-phase extraction sample preparation. Full article
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22 pages, 551 KiB  
Article
Dipole Theory of Polyzwitterion Microgels and Gels
by Murugappan Muthukumar
Gels 2024, 10(6), 393; https://doi.org/10.3390/gels10060393 - 11 Jun 2024
Viewed by 298
Abstract
The behavior of polyzwitterions, constituted by dipole-like zwitterionic monomers, is significantly different from that of uniformly charged polyelectrolytes. The origin of this difference lies in the intrinsic capacity of polyzwitterions to self-associate intramolecularly and associate with interpenetrating chains driven by dominant dipolar interactions. [...] Read more.
The behavior of polyzwitterions, constituted by dipole-like zwitterionic monomers, is significantly different from that of uniformly charged polyelectrolytes. The origin of this difference lies in the intrinsic capacity of polyzwitterions to self-associate intramolecularly and associate with interpenetrating chains driven by dominant dipolar interactions. Earlier attempts to treat polyzwitterions implicitly assume that the dipoles of zwitterion monomers are randomly oriented. At ambient temperatures, the dipolar zwitterion monomers can readily align with each other generating quadrupoles and other multipoles and thus generating heterogeneous structures even in homogeneous solutions. Towards an attempt to understand the role of such dipolar associations, we present a mean field theory of solutions of polyzwitterions. Generally, we delineate a high-temperature regime where the zwitterion dipoles are randomly oriented from a low-temperature regime where quadrupole formation is significantly prevalent. We present closed-form formulas for: (1) Coil-globule transition in the low-temperature regime, the anti-polyelectrolyte effect of chain expansion upon addition of low molar mass salt, and chain relaxation times in dilute solutions. (2) Spontaneous formation of a mesomorphic state at the borderline between the high-temperature and low-temperature regimes and its characteristics. A universal law is presented for the radius of gyration of the microgel, as a proportionality to one-sixth power of the polymer concentration. (3) Swelling equilibrium of chemically cross-linked polyzwitterion gels in both the high temperature and low-temperature regimes. Addressing the hierarchical internal dynamics of polyzwitterion gels, we present a general stretched exponential law for the time-correlation function of gel displacement vector, that can be measured in dynamic light scattering experiments. The present theory is of direct experimental relevance and additional theoretical developments to all polyzwitterion systems, and generally to biological macromolecular systems such as intrinsically disordered proteins. Full article
(This article belongs to the Special Issue Recent Advances in Thermoreversible Gelation)
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10 pages, 2159 KiB  
Article
Molten Alkali-Assisted Formation of Silicate Gels and Its Application for Preparing Zeolites
by Juan Ye, Yanchun Yang, Li Zhang, Man Li, Yiling Wang, Yuxuan Chen, Ruhui Ling, Jiefeng Yan, Yan Chen, Jinxing Hu and Zhenxing Fang
Gels 2024, 10(6), 392; https://doi.org/10.3390/gels10060392 - 9 Jun 2024
Viewed by 273
Abstract
Fly ash was used as raw material to prepare zeolites through silicate gels, assisted bythe hydrothermal method. The silicate gels could be effectively formed in a few minutes in a molten alkali environment. The zeolites could be prepared by using these silicate gels [...] Read more.
Fly ash was used as raw material to prepare zeolites through silicate gels, assisted bythe hydrothermal method. The silicate gels could be effectively formed in a few minutes in a molten alkali environment. The zeolites could be prepared by using these silicate gels through the hydrothermal method, which realizes the transformation from useless materials to highly valuable materials. The obtained zeoliteswere applied to the removal of ammonium in water, achieving the highvalue utilization of fly ash. The synthesized zeolites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrum (EDS), thermogravimetric (TG),and Fourier transform infrared (FTIR) spectroscopy. The study on the adsorption and removal of ammonium in water shows that the adsorption of ammonium is more in line with pseudo first-order kinetics, and the adsorption mainly occurs in the first 20 min. The adsorption can reach equilibrium in 30 minutes, and the maximum adsorption capacity can reach 49.1 mg/g. The adsorption capacity of ammonium has the best performance at pH = 5. Furthermore, within a certain range, an increase in temperature is beneficial for the removal of ammonium. Full article
(This article belongs to the Special Issue Gels for Removal and Adsorption (2nd Edition))
23 pages, 12453 KiB  
Article
Donkey Gelatin and Keratin Nanofibers Loaded with Antioxidant Agents for Wound Healing Dressings
by Maria Râpă, Carmen Gaidau, Laura Mihaela Stefan, Andrada Lazea-Stoyanova, Mariana Daniela Berechet, Andreea Iosageanu, Ecaterina Matei, Virginija Janauskaitė, Cristian Predescu, Virgilijus Valeika, Aistė Balčiūnaitienė and Snezana Cupara
Gels 2024, 10(6), 391; https://doi.org/10.3390/gels10060391 - 8 Jun 2024
Viewed by 432
Abstract
Acute and chronic wounds present a significant healthcare challenge, requiring innovative solutions for effective treatment. The exploitation of natural by-products with advanced cell regeneration potential and plant-based materials, which possess bioactive properties, is an innovative topic in wound management. This study investigates the [...] Read more.
Acute and chronic wounds present a significant healthcare challenge, requiring innovative solutions for effective treatment. The exploitation of natural by-products with advanced cell regeneration potential and plant-based materials, which possess bioactive properties, is an innovative topic in wound management. This study investigates the potential of donkey gelatin and keratin for blending with natural bioactive extracts such as sumac, curcumin, and oak acorn to fabricate antioxidant and antimicrobial nanofibers with accelerated wound healing processes. The fabricated nanofibers possess good in vitro biocompatibility, except for the sumac-based donkey nanofibers, where cell viability significantly dropped to 56.25% (p < 0.05 compared to non-treated cells). The nanofiber dimensions showed structural similarities to human extracellular matrix components, providing an ideal microenvironment for tissue regeneration. The donkey nanofiber-based sumac and curcumin extracts presented a higher dissolution in the first 10 min (74% and 72%). Curcumin extract showed similar antimicrobial and antifungal performances to rivanol, while acorn and sumac extracts demonstrated similar values to each other. In vitro tests performed on murine fibroblast cells demonstrated high migration rates of 89% and 85% after 24 h in the case of acorn and curcumin nanofibers, respectively, underscoring the potential of these nanofibers as versatile platforms for advanced wound care applications. Full article
(This article belongs to the Special Issue Design and Development of Gelatin-Based Materials)
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13 pages, 4482 KiB  
Article
Preparation and Characterization of Chitosan/Hydroxypropyl Methylcellulose Temperature-Sensitive Hydrogel Containing Inorganic Salts for Forest Fire Suppression
by Yanni Gao, Yuzhou Zhao and Ting Wang
Gels 2024, 10(6), 390; https://doi.org/10.3390/gels10060390 - 8 Jun 2024
Viewed by 473
Abstract
Effective forest fire suppression remains a critical challenge, necessitating innovative solutions. Temperature-sensitive hydrogels represent a promising avenue in this endeavor. Traditional firefighting methods often struggle to address forest fires efficiently while mitigating ecological harm and optimizing resource utilization. In this study, a novel [...] Read more.
Effective forest fire suppression remains a critical challenge, necessitating innovative solutions. Temperature-sensitive hydrogels represent a promising avenue in this endeavor. Traditional firefighting methods often struggle to address forest fires efficiently while mitigating ecological harm and optimizing resource utilization. In this study, a novel intelligent temperature-sensitive hydrogel was prepared specially for forest fire extinguishment. Utilizing a one-pot synthesis approach, this material demonstrates exceptional fluidity at ambient temperatures, facilitating convenient application and transport. Upon exposure to elevated temperatures, it undergoes a phase transition to form a solid, barrier-like structure essential for containing forest fires. The incorporation of environmentally friendly phosphorus salts into the chitosan/hydroxypropyl methylcellulose gel system enhances the formation of temperature-sensitive hydrogels, thereby enhancing their structural integrity and firefighting efficacy. Morphological and thermal stability analyses elucidate the outstanding performance, with the hydrogel forming a dense carbonized layer that acts as a robust barrier against the spread of forest fires. Additionally, comprehensive evaluations employing rheological tests, cone calorimeter tests, a swelling test, and infrared thermography reveal the multifaceted roles of temperature-sensitive hydrogels in forest fire prevention and suppression strategies. Full article
(This article belongs to the Section Gel Analysis and Characterization)
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27 pages, 12339 KiB  
Review
Potential of Carbon Aerogels in Energy: Design, Characteristics, and Applications
by Gazi A. K. M. Rafiqul Bari and Jae-Ho Jeong
Gels 2024, 10(6), 389; https://doi.org/10.3390/gels10060389 - 7 Jun 2024
Viewed by 514
Abstract
In energy applications, the use of materials with hierarchical porous structures and large surface areas is essential for efficient charge storage. These structures facilitate rapid electron and ion transport, resulting in high power density and quick charge/discharge capabilities. Carbon-based materials are extensively utilized [...] Read more.
In energy applications, the use of materials with hierarchical porous structures and large surface areas is essential for efficient charge storage. These structures facilitate rapid electron and ion transport, resulting in high power density and quick charge/discharge capabilities. Carbon-based materials are extensively utilized due to their tunable properties, including pore sizes ranging from ultra- to macropores and surface polarity. Incorporating heteroatoms such as nitrogen, oxygen, sulfur, phosphorus, and boron modifies the carbon structure, enhancing electrocatalytic properties and overall performance. A hierarchical pore structure is necessary for optimal performance, as it ensures efficient access to the material’s core. The microstructure of carbon materials significantly impacts energy storage, with factors like polyaromatic condensation, crystallite structure, and interlayer distance playing crucial roles. Carbon aerogels, derived from the carbonization of organic gels, feature a sponge-like structure with large surface area and high porosity, making them suitable for energy storage. Their open pore structure supports fast ion transfer, leading to high energy and power densities. Challenges include maintaining mechanical or structural integrity, multifunctional features, and scalability. This review provides an overview of the current progress in carbon-based aerogels for energy applications, discussing their properties, development strategies, and limitations, and offering significant guidance for future research requirements. Full article
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12 pages, 3708 KiB  
Article
Study on Adsorption of Cd in Solution and Soil by Modified Biochar–Calcium Alginate Hydrogel
by Shuyue Wang, Yajun Wang, Xinyi Wang, Sijia Sun, Yanru Zhang, Weixiong Jiao and Dasong Lin
Gels 2024, 10(6), 388; https://doi.org/10.3390/gels10060388 - 6 Jun 2024
Viewed by 467
Abstract
Contamination with cadmium (Cd) is a prominent issue in agricultural non-point source pollution in China. With the deposition and activation of numerous Cd metal elements in farmland, the problem of excessive pollution of agricultural produce can no longer be disregarded. Considering the issue [...] Read more.
Contamination with cadmium (Cd) is a prominent issue in agricultural non-point source pollution in China. With the deposition and activation of numerous Cd metal elements in farmland, the problem of excessive pollution of agricultural produce can no longer be disregarded. Considering the issue of Cd pollution in farmland, this study proposes the utilization of cross-linked modified biochar (prepared from pine wood) and calcium alginate hydrogels to fabricate a composite material which is called MB-CA for short. The aim is to investigate the adsorption and passivation mechanism of soil Cd by this innovative composite. The MB-CA exhibits a higher heavy metal adsorption capacity compared to traditional biochar and hydrogel due to its increased oxygen-containing functional groups and heavy metal adsorption sites. In the Cd solution adsorption experiment, the highest Cd2+ removal rate reached 85.48%. In addition, it was found that the material also has an excellent pH improvement effect. Through the adsorption kinetics experiment and the soil culture experiments, it was determined that MB-CA adheres to the quasi-second-order kinetic model and is capable of adsorbing 35.94% of Cd2+ in soil. This study validates the efficacy of MB-CA in the adsorption and passivation of Cd in soil, offering a novel approach for managing Cd-contaminated cultivated land. Full article
(This article belongs to the Special Issue Gels for Removal and Adsorption (2nd Edition))
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20 pages, 8361 KiB  
Review
Bacterial Cellulose: A Sustainable Source for Hydrogels and 3D-Printed Scaffolds for Tissue Engineering
by Elena Utoiu, Vasile Sorin Manoiu, Elena Iulia Oprita and Oana Craciunescu
Gels 2024, 10(6), 387; https://doi.org/10.3390/gels10060387 - 5 Jun 2024
Viewed by 470
Abstract
Bacterial cellulose is a biocompatible biomaterial with a unique macromolecular structure. Unlike plant-derived cellulose, bacterial cellulose is produced by certain bacteria, resulting in a sustainable material consisting of self-assembled nanostructured fibers with high crystallinity. Due to its purity, bacterial cellulose is appealing for [...] Read more.
Bacterial cellulose is a biocompatible biomaterial with a unique macromolecular structure. Unlike plant-derived cellulose, bacterial cellulose is produced by certain bacteria, resulting in a sustainable material consisting of self-assembled nanostructured fibers with high crystallinity. Due to its purity, bacterial cellulose is appealing for biomedical applications and has raised increasing interest, particularly in the context of 3D printing for tissue engineering and regenerative medicine applications. Bacterial cellulose can serve as an excellent bioink in 3D printing, due to its biocompatibility, biodegradability, and ability to mimic the collagen fibrils from the extracellular matrix (ECM) of connective tissues. Its nanofibrillar structure provides a suitable scaffold for cell attachment, proliferation, and differentiation, crucial for tissue regeneration. Moreover, its mechanical strength and flexibility allow for the precise printing of complex tissue structures. Bacterial cellulose itself has no antimicrobial activity, but due to its ideal structure, it serves as matrix for other bioactive molecules, resulting in a hybrid product with antimicrobial properties, particularly advantageous in the management of chronic wounds healing process. Overall, this unique combination of properties makes bacterial cellulose a promising material for manufacturing hydrogels and 3D-printed scaffolds, advancing the field of tissue engineering and regenerative medicine. Full article
(This article belongs to the Special Issue Advances in Cellulose-Based Hydrogels (3rd Edition))
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12 pages, 2780 KiB  
Article
Molecular Recognition between Carbon Dioxide and Biodegradable Hydrogel Models: A Density Functional Theory (DFT) Investigation
by Domingo Cesar Carrascal-Hernandez, Maximiliano Mendez-Lopez, Daniel Insuasty, Samira García-Freites, Marco Sanjuan and Edgar Márquez
Gels 2024, 10(6), 386; https://doi.org/10.3390/gels10060386 - 5 Jun 2024
Viewed by 367
Abstract
In this research, we explore the potential of employing density functional theory (DFT) for the design of biodegradable hydrogels aimed at capturing carbon dioxide (CO2) and mitigating greenhouse gas emissions. We employed biodegradable hydrogel models, including polyethylene glycol, polyvinylpyrrolidone, chitosan, and [...] Read more.
In this research, we explore the potential of employing density functional theory (DFT) for the design of biodegradable hydrogels aimed at capturing carbon dioxide (CO2) and mitigating greenhouse gas emissions. We employed biodegradable hydrogel models, including polyethylene glycol, polyvinylpyrrolidone, chitosan, and poly-2-hydroxymethacrylate. The complexation process between the hydrogel and CO2 was thoroughly investigated at the ωB97X-D/6-311G(2d,p) theoretical level. Our findings reveal a strong affinity between the hydrogel models and CO2, with binding energies ranging from −4.5 to −6.5 kcal/mol, indicative of physisorption processes. The absorption order observed was as follows: chitosan > PVP > HEAC > PEG. Additionally, thermodynamic parameters substantiated this sequence and even suggested that these complexes remain stable up to 160 °C. Consequently, these polymers present a promising avenue for crafting novel materials for CO2 capture applications. Nonetheless, further research is warranted to optimize the design of these materials and assess their performance across various environmental conditions. Full article
(This article belongs to the Special Issue Gel-Based Materials for Biomedical Engineering)
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20 pages, 12251 KiB  
Article
In Situ Gelling Behavior and Biopharmaceutical Characterization of Nano-Silver-Loaded Poloxamer Matrices Designed for Nasal Drug Delivery
by Nadezhda Ivanova, Neli Ermenlieva, Lora Simeonova, Neli Vilhelmova-Ilieva, Kameliya Bratoeva, Georgi Stoyanov and Velichka Andonova
Gels 2024, 10(6), 385; https://doi.org/10.3390/gels10060385 - 5 Jun 2024
Viewed by 361
Abstract
A combination of Poloxamer 407 (P407) and hydroxypropyl methylcellulose (HPMC) hydrosols is proposed as an in situ thermo-gelling vehicle for the nasal drug delivery of chlorhexidine–silver nanoparticles conjugates (SN-CX). Optimization of the formulation was carried out by applying varying ratios of P407 and [...] Read more.
A combination of Poloxamer 407 (P407) and hydroxypropyl methylcellulose (HPMC) hydrosols is proposed as an in situ thermo-gelling vehicle for the nasal drug delivery of chlorhexidine–silver nanoparticles conjugates (SN-CX). Optimization of the formulation was carried out by applying varying ratios of P407 and HPMC in the presence and absence of SN-CX so that gelation would occur in the temperature range of the nasal cavity (30–34 °C). Mechanisms for the observed gelation phenomena were suggested based on viscosimetry, texture analysis, and dynamic light scattering. Tests were carried out for sprayability, washout time, in vitro drug release, ex vivo permeation, and antimicrobial activity. When applied separately, HPMC was found to lower the P407 gelation temperature (Tg), whereas SN-CX increased it. However, in the presence of HPMC, SN-CX interfered with the P407 micellar organization in a principally contrasting way while leading to an even further decrease in Tg. SN-CX-loaded nasal formulations composed of P407 16% and HPMC 0.1% demonstrated a desired gelation at 31.9 °C, good sprayability (52.95% coverage of the anterior nasal cavity), mucoadhesion for 70 min under simulated nasal clearance, expedient release and permeation, and preserved anti-infective activity against seasonal Influenza virus and beta-coronavirus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus and other pathogens. Our findings suggest that the current development could be considered a potential formulation of a protective nasal spray against respiratory infections. Full article
(This article belongs to the Special Issue Hydrogelated Matrices: Structural, Functional and Applicative Aspects)
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17 pages, 2827 KiB  
Article
Development and Characterization of Ethylcellulose Oleogels Based on Pumpkin Seed Oil and Rapeseed Oil
by Claudiu-Ștefan Ursachi, Simona Perța-Crișan, Iolanda Tolan, Dorina Rodica Chambre, Bianca-Denisa Chereji, Dumitru Condrat and Florentina-Daniela Munteanu
Gels 2024, 10(6), 384; https://doi.org/10.3390/gels10060384 - 5 Jun 2024
Viewed by 435
Abstract
In contrast to rapeseed oil, pumpkin seed oil has yet to be well investigated in terms of oleogelation, and, to the best of our knowledge, no study related to the use of ethylcellulose (EC) in the structuring of this oil has been identified [...] Read more.
In contrast to rapeseed oil, pumpkin seed oil has yet to be well investigated in terms of oleogelation, and, to the best of our knowledge, no study related to the use of ethylcellulose (EC) in the structuring of this oil has been identified in the current scientific literature. Therefore, the present study evaluated several oleogels formulated with EC as the oleogelator in different concentrations of 7% (OG7) and 9% (OG9), based on cold-pressed pumpkin seed oil (PO) and refined rapeseed oil (RO), as well as on mixtures of the two oils in different combinations: PO:RO (3:1) (PRO) and PO:RO (1:1) (RPO). Physicochemical properties such as visual appearance, gel formation time (GFT), oil-binding capacity (OBC), oxidative and thermal stability, and textural characteristics were analyzed. Analysis of variance (ANOVA) and Tukey’s honestly significant difference (HSD) were used in the statistical analysis of the data, with a significance level of p < 0.05. EC proved to be an effective structuring agent of the mentioned edible oils; the type of oils and the concentration of oleogelator significantly influenced the characteristics of the obtained oleogels. The 9% EC oleogels exhibited a more rigid structure, with a higher OBC and a reduced GFT. Pumpkin seed oil led to more stable oleogels, while the mixture of pumpkin seed oil with rapeseed oil caused a significant reduction in their mechanical properties and decreased the OBC. After 14 days of storage, all oleogels demonstrated proper oxidative stability within the bounds set by international regulations for edible fats, regardless of the kind of oil and EC concentration. All of the oleogels showed a higher oxidative stability than the oils utilized in their formulation; however, those prepared with cold-pressed pumpkin seed oil indicated a lower level of lipid oxidation among all oleogels. The P-OG9 and PR-OG9 oleogels, which mainly included PO and contained 9% EC, demonstrated the optimum levels of quality in texture, GFT, OBC, and oxidative stability. Full article
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2 pages, 1060 KiB  
Retraction
RETRACTED: Aldakheel et al. Employing of Curcumin–Silver Nanoparticle-Incorporated Sodium Alginate-Co-Acacia Gum Film Hydrogels for Wound Dressing. Gels 2023, 9, 780
by Fahad M. Aldakheel, Dalia Mohsen, Marwa M. El Sayed, Mohammed H. Fagir and Dalia K. El Dein
Gels 2024, 10(6), 383; https://doi.org/10.3390/gels10060383 - 5 Jun 2024
Viewed by 195
Abstract
The Gels Editorial Office retracts the article, “Employing of Curcumin–Silver Nanoparticle-Incorporated Sodium Alginate-Co-Acacia Gum Film Hydrogels for Wound Dressing” [...] Full article
(This article belongs to the Special Issue Hydrogel for Sustained Delivery of Therapeutic Agents)
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20 pages, 5034 KiB  
Article
Development and Characterization of a Sol–Gel-Functionalized Glass Carbon Electrode Probe for Sensing Ultra-Trace Amounts of NH3 and NH4+ in Water
by H. Alwael, M. Oubaha and M. S. El-Shahawi
Gels 2024, 10(6), 382; https://doi.org/10.3390/gels10060382 - 4 Jun 2024
Viewed by 348
Abstract
This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol–gel coating integrated onto a glassy carbon electrode (sol–gel/GCE) for the detection of NH3 and/or NH4+ in water. The main [...] Read more.
This study centers on the development and characterization of an innovative electrochemical sensing probe composed of a sensing mesoporous functional sol–gel coating integrated onto a glassy carbon electrode (sol–gel/GCE) for the detection of NH3 and/or NH4+ in water. The main interest for integrating a functional sol–gel coating onto a GCE is to increase the selective and sensing properties of the GCE probe towards NH3 and/or NH4+ ions. The structure and surface morphology of the newly developed sol–gel/GCE probe were characterized employing scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR), while the electrochemical sensing properties were evaluated by Berthelot’s reaction, cyclic voltammetry (CV), and adsorptive square wave–anodic striping voltammetry (Ads SW–ASV). It is shown that the newly developed sol–gel coating is homogeneously deposited on the GCE with a sub-micron and uniform thickness close to 630 nm and a surface roughness of 25 nm. The sensing testing of the sol–gel/GCE probe showed limits of detection and limits of quantitation of 1.7 and 5.56 nM of NH4+, respectively, as well as a probe sensitivity of 5.74 × 10−1 μA/μM cm−2. The developed probe was fruitfully validated for the selective detection of NH3/NH4+ in fresh and sea water samples. Computed Student texp (0.45–1.25) and Fexp (1.69–1.78) (n = 5) tests were less than the theoretical ttab (2.78) and Ftab (6.39) at 95% probability. Full article
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32 pages, 5154 KiB  
Review
A Comprehensive Review of Radiation-Induced Hydrogels: Synthesis, Properties, and Multidimensional Applications
by Md. Shahriar Ahmed, Mobinul Islam, Md. Kamrul Hasan and Kyung-Wan Nam
Gels 2024, 10(6), 381; https://doi.org/10.3390/gels10060381 - 2 Jun 2024
Viewed by 444
Abstract
At the forefront of advanced material technology, radiation-induced hydrogels present a promising avenue for innovation across various sectors, utilizing gamma radiation, electron beam radiation, and UV radiation. Through the unique synthesis process involving radiation exposure, these hydrogels exhibit exceptional properties that make them [...] Read more.
At the forefront of advanced material technology, radiation-induced hydrogels present a promising avenue for innovation across various sectors, utilizing gamma radiation, electron beam radiation, and UV radiation. Through the unique synthesis process involving radiation exposure, these hydrogels exhibit exceptional properties that make them highly versatile and valuable for a multitude of applications. This paper focuses on the intricacies of the synthesis methods employed in creating these radiation-induced hydrogels, shedding light on their structural characteristics and functional benefits. In particular, the paper analyzes the diverse utility of these hydrogels in biomedicine and agriculture, showcasing their potential for applications such as targeted drug delivery, injury recovery, and even environmental engineering solutions. By analyzing current research trends and highlighting potential future directions, this review aims to underscore the transformative impact that radiation-induced hydrogels could have on various industries and the advancement of biomedical and agricultural practices. Full article
(This article belongs to the Special Issue Radiation-Induced Hydrogels and Their Applications)
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14 pages, 8775 KiB  
Article
Facile Synthesis of Surface-Modified Hollow-Silica (SiO2) Aerogel Particles via Oil–Water–Oil Double Emulsion Method
by Pratik S. Kapadnis, Ki-Sun Nam, Hyun-Young Kim, Hyung-Ho Park and Haejin Hwang
Gels 2024, 10(6), 380; https://doi.org/10.3390/gels10060380 - 2 Jun 2024
Viewed by 307
Abstract
Due to their high surface area and low weight, silica aerogels are ideally suited for several uses, including drug delivery, catalysis, and insulation. Oil–water–oil (OWO) double emulsion is a simple and regulated technique for encasing a volatile oil phase in a [...] Read more.
Due to their high surface area and low weight, silica aerogels are ideally suited for several uses, including drug delivery, catalysis, and insulation. Oil–water–oil (OWO) double emulsion is a simple and regulated technique for encasing a volatile oil phase in a silica shell to produce hollow silica (SiO2) aerogel particles by using hydrophilic and hydrophobic emulsifiers. In this study, the oil–water–oil (OWO) double emulsion method was implemented to synthesize surface-modified hollow silica (SiO2) aerogel particles in a facile and effective way. This investigation mainly focused on the influence of the N-hexane-to-water glass (OW) ratio (r) in the first emulsion, silica (water glass) content concentration (x), and surfactant concentration (s) variations. Furthermore, surface modification techniques were utilized to customize the aerogel’s characteristics. The X-ray diffraction (XRD) patterns showed no imprints of impurities except SiO2. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images highlight the hollow microstructure of silica particles. Zeta potential was used to determine particle size analysis of hollow silica aerogel particles. The oil–water–oil (OWO) double emulsion approach was successfully employed to synthesize surface-modified hollow silica (SiO2) aerogel particles, providing precise control over the particle characteristics. By the influence of the optimization condition, this approach improves the aerogel’s potential applications in drug delivery, catalysis, and insulation by enabling surface modifications. Full article
(This article belongs to the Special Issue Aerogels—Preparation and Properties)
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12 pages, 3682 KiB  
Communication
Assessment of Alginate Gel Films as the Orodispersible Dosage Form for Meloxicam
by Barbara Jadach, Martyna Kowalczyk and Anna Froelich
Gels 2024, 10(6), 379; https://doi.org/10.3390/gels10060379 - 2 Jun 2024
Viewed by 208
Abstract
The aim of this study was to obtain films based on sodium alginate (SA) for disintegration in the oral cavity. The films were prepared with a solvent-casting method, and meloxicam (MLX) as the active ingredient was suspended in a 3% sodium alginate solution. [...] Read more.
The aim of this study was to obtain films based on sodium alginate (SA) for disintegration in the oral cavity. The films were prepared with a solvent-casting method, and meloxicam (MLX) as the active ingredient was suspended in a 3% sodium alginate solution. Two different solid-dosage-form additives containing different disintegrating agents, i.e., VIVAPUR 112® (MCC; JRS Pharma, Rosenberg, Germany) and Prosolve EASYtabs SP® (MIX; JRS Pharma, Rosenberg, Germany), were used, and four different combinations of drying time and temperature were tested. The influence of the used disintegrant on the properties of the ODFs (orodispersible films) was investigated. The obtained films were studied for their appearance, elasticity, mass uniformity, water content, meloxicam content and, finally, disintegration time, which was studied using two different methods. The films obtained with the solvent-casting method were flexible and homogeneous in terms of MLX content. Elasticity was slightly better when MIX was used as a disintegrating agent. However, these samples also revealed worse uniformity and mechanical durability. It was concluded that the best properties of the films were achieved using the mildest drying conditions. The type of the disintegrating agent had no effect on the amount of water remaining in the film after drying. The water content depended on the drying conditions. The disintegration time was not affected by the disintegrant type, but some differences were observed when various drying conditions were applied. However, regardless of the formulation type and manufacturing conditions, the analyzed films could not be classified as fast disintegrating films, as the disintegration time exceeded 30 s in all of the tested formulations. Full article
(This article belongs to the Special Issue Chemical Properties and Application of Gel Materials)
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16 pages, 8278 KiB  
Article
Ag Nanoparticles Deposited onto BaTiO3 Aerogel for Highly Efficient Photodegradation
by Jun Wu, Wen Yan, Mengyuan Xie, Kai Zhong, Sheng Cui and Xiaodong Shen
Gels 2024, 10(6), 378; https://doi.org/10.3390/gels10060378 - 31 May 2024
Viewed by 204
Abstract
Given the increasingly severe environmental problems caused by water pollution, the degradation of organic dyes can be effectively achieved through the utilization of photocatalysis. In this work, metal alkoxides and a combination of alcohol/hydrophobic solvents are employed to prepare BaTiO3 aerogels via [...] Read more.
Given the increasingly severe environmental problems caused by water pollution, the degradation of organic dyes can be effectively achieved through the utilization of photocatalysis. In this work, metal alkoxides and a combination of alcohol/hydrophobic solvents are employed to prepare BaTiO3 aerogels via a liquid-phase and template-free synthetic route. The preparation process of the aerogels solely entails facile agitation and supercritical drying, eliminating the need for additional heat treatment. The binary solvent of ethanol and toluene is identified as the optimal choice, resulting in a significantly enhanced surface area (up to 223 m2/g) and an abundant pore structure of BaTiO3 aerogels compared to that of the BaTiO3 nanoparticles. Thus, the removal efficiency of the BaTiO3 aerogel sample for MO is nearly twice as high as that of the BaTiO3 nanoparticles sample. Noble metal Ag nanoparticles’ deposition onto the BaTiO3 aerogel surface is further achieved via the photochemical deposition method, which enhances the capture of photogenerated electrons, thereby ensuring an elevated level of photocatalytic efficiency. As a result, Ag nanoparticles deposited on BaTiO3 aerogel can degrade MO completely after 40 min of illumination, while the corresponding aerogel before modification can only remove 80% of MO after 60 min. The present work not only complements the preparatory investigation of intricate aerogels but also offers a fresh perspective for the development of diverse perovskite aerogels with broad applications. Full article
(This article belongs to the Special Issue Preparation and Characteristics of Aerogel-Based Materials)
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14 pages, 1621 KiB  
Article
Cationic Glucan Dendrimer Gel-Mediated Local Delivery of Anti-OC-STAMP-siRNA for Treatment of Pathogenic Bone Resorption
by Kenta Yamamoto, Shin-Ichi Sawada, Satoru Shindo, Shin Nakamura, Young M. Kwon, Nazanin Kianinejad, Saynur Vardar, Maria Hernandez, Kazunari Akiyoshi and Toshihisa Kawai
Gels 2024, 10(6), 377; https://doi.org/10.3390/gels10060377 - 31 May 2024
Viewed by 254
Abstract
Osteoclast stimulatory transmembrane protein (OC-STAMP) plays a pivotal role in the promotion of cell fusion during osteoclast differentiation (osteoclastogenesis) in the context of pathogenic bone resorption. Thus, it is plausible that the suppression of OC-STAMP through a bioengineering approach could lead to the [...] Read more.
Osteoclast stimulatory transmembrane protein (OC-STAMP) plays a pivotal role in the promotion of cell fusion during osteoclast differentiation (osteoclastogenesis) in the context of pathogenic bone resorption. Thus, it is plausible that the suppression of OC-STAMP through a bioengineering approach could lead to the development of an effective treatment for inflammatory bone resorptive diseases with minimum side effects. Here, we synthesized two types of spermine-bearing (Spe) cationic glucan dendrimer (GD) gels (with or without C12) as carriers of short interfering RNA (siRNA) to silence OC-STAMP. The results showed that amphiphilic C12-GD-Spe gel was more efficient in silencing OC-STAMP than GD-Spe gel and that the mixture of anti-OC-STAMP siRNA/C12-GD-Spe significantly downregulated RANKL-induced osteoclastogenesis. Also, local injection of anti-OC-STAMP-siRNA/C12-GD-Spe could attenuate bone resorption induced in a mouse model of periodontitis. These results suggest that OC-STAMP is a promising target for the development of a novel bone regenerative therapy and that C12-GD-Spe gel provides a new nanocarrier platform of gene therapies for osteolytic disease. Full article
(This article belongs to the Section Gel Applications)
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