Gels

14 pages, 9261 KiB

Open AccessArticle

Stretchable and Shape-Transformable Organohydrogel with Gallium Mesh Frame

by Mincheol Lee, Youngjin Choi, Young Min Bae, Seonghyeon Nam and Kiyoung Shin

Gels 2024, 10(12), 769; https://doi.org/10.3390/gels10120769 (registering DOI) - 26 Nov 2024

Shape-memory materials are widely utilized in biomedical devices and tissue engineering, particularly for their ability to undergo predefined shape changes in response to external stimuli. In this study, a shape-transformable organohydrogel was developed by incorporating a gallium mesh into a polyacrylamide/alginate/glycerol matrix. The [...] Read more.

Shape-memory materials are widely utilized in biomedical devices and tissue engineering, particularly for their ability to undergo predefined shape changes in response to external stimuli. In this study, a shape-transformable organohydrogel was developed by incorporating a gallium mesh into a polyacrylamide/alginate/glycerol matrix. The gallium mesh, which transitions between solid and liquid states at moderate temperatures (~29.8 °C), enhanced the hydrogel’s mechanical properties and enabled shape-memory functionality. The composite organohydrogel exhibited a high elastic modulus of ~900 kPa in the solid gallium state and ~30 kPa in the liquid gallium state, enabling reversible deformation and structural stability. Glycerol improved the hydrogel’s moisture retention, maintaining stretchability and repeated heating and cooling cycles. After multiple cycles of the shape-changing process, the organohydrogel retained its mechanical integrity, achieving shape-fixation and recovery ratios of ~96% and 95%, respectively. This combination of shape-memory functionality, stretchability, and mechanical stability makes this organohydrogel highly suitable for applications in flexible electronics, soft robotics, and biomedical devices, where adaptability and shape retention are essential. Full article

(This article belongs to the Section Gel Processing and Engineering)

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37 pages, 9715 KiB

Open AccessReview

Molecular Design and Nanoarchitectonics of Inorganic–Organic Hybrid Sol–Gel Systems for Antifouling Coatings

by Markus Bös, Ludwig Gabler, Willi Max Leopold, Max Steudel, Mareike Weigel and Konstantin Kraushaar

Gels 2024, 10(12), 768; https://doi.org/10.3390/gels10120768 - 25 Nov 2024

Abstract

Environmental protection, especially fouling protection, is a very topical and wide-ranging issue. This review explores the development, molecular design, and nanoarchitectonics of sol–gel-based hybrid coatings for antifouling applications. These coatings combine inorganic and organic materials, offering enhanced stability and adaptability, making them ideal [...] Read more.

Environmental protection, especially fouling protection, is a very topical and wide-ranging issue. This review explores the development, molecular design, and nanoarchitectonics of sol–gel-based hybrid coatings for antifouling applications. These coatings combine inorganic and organic materials, offering enhanced stability and adaptability, making them ideal for protecting surfaces from fouling. This review covers key antifouling strategies from the past decade, including biocidal additives, fouling resistance, release mechanisms, and surface topological modifications. The sol–gel hybrid systems prevent biofilm formation and organism attachment by leveraging molecular interactions, making them particularly useful in marine environments. Additionally, the study emphasizes the coatings’ environmental benefits, as they offer a potential alternative to traditional toxic antifouling methods. Overall, this research underscores the importance of sol–gel technologies in advancing eco-friendly antifouling solutions. Full article

(This article belongs to the Special Issue Gel Formation and Processing Technologies for Material Applications)

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16 pages, 3002 KiB

Open AccessArticle

In Vitro Characterization of Human Cell Sources in Collagen Type I Gel Scaffold for Meniscus Tissue Engineering

by Barbara Canciani, Nicolò Rossi, Elena Arrigoni, Riccardo Giorgino, Mirko Sergio, Lucia Aidos, Mauro Di Giancamillo, Valentina Rafaela Herrera Millar, Giuseppe M. Peretti, Alessia Di Giancamillo and Laura Mangiavini

Gels 2024, 10(12), 767; https://doi.org/10.3390/gels10120767 - 25 Nov 2024

Abstract

Strategies to repair the meniscus have achieved limited success; thus, a cell-based therapy combined with an appropriate biocompatible scaffold could be an interesting alternative to overcome this issue. The aim of this project is to analyze different cell populations and a collagen gel [...] Read more.

Strategies to repair the meniscus have achieved limited success; thus, a cell-based therapy combined with an appropriate biocompatible scaffold could be an interesting alternative to overcome this issue. The aim of this project is to analyze different cell populations and a collagen gel scaffold as a potential source for meniscus tissue engineering applications. Dermal fibroblasts (DFs) and mesenchymal stem cells (MSCs) isolated from adipose tissue (ASCs) or bone marrow (BMSCs) were analyzed. Two different fibro-chondrogenic media, M1 and M2, were tested, and qualitative and quantitative analyses were performed. Significant increases in glycosaminoglycans (GAGs) production and in fibro-cartilaginous marker expression were observed in MSCs in the presence of M1 medium. In addition, both ASCs and BMSCs cultured in M1 medium were used in association with the collagen hydrogel (MSCs-SCF) for the development of an in vitro meniscal-like tissue. Significant up-regulation in GAGs production and in the expression of aggrecan, collagen type I, and collagen type II was observed in BMSCs-SCF. This study improves knowledge of the potential of combining undifferentiated MSCs with a collagen gel as a new tissue engineering strategy for meniscus repair. Full article

(This article belongs to the Special Issue Recent Research on Medical Hydrogels)

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19 pages, 3572 KiB

Open AccessArticle

The Effect of Cellulose Nanocrystals on the Molecular Organization, Thermomechanical, and Shape Memory Properties of Gelatin-Matrix Composite Films

by Cristina Padilla, Marzena Pępczyńska, Cristian Vizueta, Franck Quero, Paulo Díaz-Calderón, William Macnaughtan, Tim Foster and Javier Enrione

Gels 2024, 10(12), 766; https://doi.org/10.3390/gels10120766 - 25 Nov 2024

Abstract

Gelatin is a natural hydrocolloid with excellent film-forming properties, high processability, and tremendous potential in the field of edible coatings and food packaging. However, its reinforcing by materials such as cellulose nanocrystals (CNC) is often necessary to improve its mechanical behavior, including shape [...] Read more.

Gelatin is a natural hydrocolloid with excellent film-forming properties, high processability, and tremendous potential in the field of edible coatings and food packaging. However, its reinforcing by materials such as cellulose nanocrystals (CNC) is often necessary to improve its mechanical behavior, including shape memory properties. Since the interaction between these polymers is complex and its mechanism still remains unclear, this work aimed to study the effect of low concentrations of CNC (2, 6, and 10 weight%) on the molecular organization, thermomechanical, and shape memory properties in mammalian gelatin-based composite films at low moisture content (~10 weight% dry base). The results showed that the presence of CNCs (with type I and type II crystals) interfered with the formation of the gelatin triple helix, with a decrease from 21.7% crystallinity to 12% in samples with 10% CNC but increasing the overall crystallinity (from 21.7% to 22.6% in samples with 10% CNC), which produced a decrease in the water monolayer in the composites. These changes in crystallinity also impacted significantly their mechanical properties, with higher E’ values (from 1 × 10⁴ to 1.3 × 10⁴ Pa at 20 °C) and improved thermal stability at higher CNC content. Additionally, the evaluation of their shape memory properties indicated that while molecular interactions between the two components occur, CNCs negatively impacted the magnitude and kinetics of the shape recovery of the composites (more particularly at 10 weight% CNC, reducing shape recovery from 90% to 70%) by reducing the netting point associated with the lower crystallinity of the gelatin. We believe that our results contribute in elucidating the interactions of gelatin–CNC composites at various structural levels and highlights that even though CNC acts as a reinforcement material on gelatin matrices, their interaction are complex and do not imply synergism in their properties. Further investigation is, however, needed to understand CNC–gelatin interfacial interactions with the aim of modulating their interactions depending on their desired application. Full article

(This article belongs to the Special Issue Design and Development of Gelatin-Based Materials)

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21 pages, 4778 KiB

Open AccessArticle

Experimental Evaluation of a Recrosslinkable CO₂-Resistant Micro-Sized Preformed Particle Gel for CO₂ Sweep Efficiency Improvement in Reservoirs with Super-K Channels

by Adel Alotibi, Tao Song, Ali Al Brahim, Baojun Bai and Thomas Schuman

Gels 2024, 10(12), 765; https://doi.org/10.3390/gels10120765 - 24 Nov 2024

Abstract

A recrosslinkable CO₂-resistant branched preformed particle gel (CO₂-BRPPG) was developed for controlling CO₂ injection conformance, particularly in reservoirs with super-permeable channels. Previous work focused on a millimeter-sized CO₂-BRPPG in open fractures, but its performance in high-permeability [...] Read more.

A recrosslinkable CO₂-resistant branched preformed particle gel (CO₂-BRPPG) was developed for controlling CO₂ injection conformance, particularly in reservoirs with super-permeable channels. Previous work focused on a millimeter-sized CO₂-BRPPG in open fractures, but its performance in high-permeability channels with pore throat networks remained unexplored. This study used a sandpack model to evaluate a micro-sized CO₂-BRPPG under varying conditions of salinity, gel concentration, and pH. At ambient conditions, the equilibrium swelling ratio (ESR) of the gel reached 76 times its original size. This ratio decreased with increasing salinity but remained stable at low pH values, demonstrating the gel’s resilience in acidic environments. Rheological tests revealed shear-thinning behavior, with gel strength improving as salinity increased (the storage modulus rose from 113 Pa in 1% NaCl to 145 Pa in 10% NaCl). Injectivity tests showed that lower gel concentrations reduced the injection pressure, offering flexibility in deep injection treatments. Gels with higher swelling ratios had lower injection pressures due to increased strength and reduced deformability. The gel maintained stable plugging performance during two water-alternating-CO₂ cycles, but a decline was observed in the third cycle. It also demonstrated a high CO₂ breakthrough pressure of 177 psi in high salinity conditions (10% NaCl). The permeability reduction for water and CO₂ was influenced by gel concentration and salinity, with higher salinity increasing the permeability reduction and higher gel concentrations decreasing it. These findings underscore the effectiveness of the CO₂-BRPPG in improving CO₂ sweep efficiency and managing CO₂ sequestration in reservoirs with high permeability. Full article

(This article belongs to the Special Issue Advances in Polymeric Gels and Applications for Hydrocarbon Development and Geologic Carbon Storage)

15 pages, 4134 KiB

Open AccessArticle

Enhanced Ammonia Capture for Adsorption Heat Pumps Using a Salt-Embedded COF Aerogel Composite

by Hiluf T. Fissaha and Duckjong Kim

Gels 2024, 10(12), 764; https://doi.org/10.3390/gels10120764 - 24 Nov 2024

Abstract

Adsorption heat pumps (AHPs) have garnered significant attention due to their efficient use of low-grade thermal energy, eco-friendly nature, and cost-effectiveness. However, a significant challenge lies in developing adsorbent materials that can achieve a high uptake capacity, rapid adsorption rates, and efficient reversible [...] Read more.

Adsorption heat pumps (AHPs) have garnered significant attention due to their efficient use of low-grade thermal energy, eco-friendly nature, and cost-effectiveness. However, a significant challenge lies in developing adsorbent materials that can achieve a high uptake capacity, rapid adsorption rates, and efficient reversible release of refrigerants, such as ammonia (NH₃). Herein, we developed and synthesized a novel salt-embedded covalent organic framework (COF) composite material designed for enhanced NH₃ capture. This material was prepared by encapsulating sodium bromide (NaBr) within a porous and densely functionalized sulfonic acid-based COF. The COF was synthesized through a Schiff base (imine) condensation reaction, providing a robust platform for effective NaBr impregnation. The COF-based aerogel composite powder was investigated for its potential in ammonia-based AHPs, benefiting from both the porous, highly functionalized COF structure and the strong NH₃ affinity of the impregnated NaBr. The composite adsorbent demonstrates an impressive NH₃ adsorption capacity, adsorption rate, and stability. The exceptional NH₃ adsorption performance of the COF-based aerogel composite powder is primarily attributed to the uniformly dispersed NaBr within the COF, the coordination of NH₃ molecules with Na⁺ ions, and the hydrogen bonding interaction between NH₃ and Br- ions. These findings highlight the potential of the salt-embedded COF composite for use in NH₃-based AHPs, gas separation, and other related applications. Full article

(This article belongs to the Special Issue Recent Progress and Development of Advanced Aerogels: Latest Processing Methods, Improved Properties and Application (2nd Edition))

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12 pages, 1837 KiB

Open AccessArticle

Modifying the Resistant Starch Content and the Retrogradation Characteristics of Potato Starch Through High-Dose Gamma Irradiation

by Zhangchi Peng, Xuwei Wang, Zhijie Liu, Liang Zhang, Linrun Cheng, Jiahao Nia, Youming Zuo, Xiaoli Shu and Dianxing Wu

Gels 2024, 10(12), 763; https://doi.org/10.3390/gels10120763 - 24 Nov 2024

Abstract

Potato starch is widely utilized in the food industry. Gamma irradiation is a cost-effective and environmentally friendly method for starch modification. Nevertheless, there is a scarcity of comprehensive and consistent knowledge regarding the physicochemical characteristics of high-dose gamma-irradiated potato starch, retrogradation properties in [...] Read more.

Potato starch is widely utilized in the food industry. Gamma irradiation is a cost-effective and environmentally friendly method for starch modification. Nevertheless, there is a scarcity of comprehensive and consistent knowledge regarding the physicochemical characteristics of high-dose gamma-irradiated potato starch, retrogradation properties in particular. In this study, potato starch was exposed to gamma rays at doses of 0, 30, 60, 90, and 120 kGy. Various physicochemical properties, including retrogradation characteristics, were investigated. Generally, the apparent amylose content (AAC), water absorption, gel viscosity, gel hardness, and gumminess decreased as the doses of gamma irradiation increased. Conversely, the resistant starch (RS), amylose content evaluated by the concanavalin A precipitation method, water solubility, and enthalpy of gelatinization were increased. Additionally, swelling power, crystalline structure, and amylopectin branch chain length distribution either remained stable or exhibited only minor changes. Notably, the degree of retrogradation of potato starches on day 7 was positively correlated with the doses of gamma irradiation. Full article

(This article belongs to the Special Issue Natural Bioactive Compounds and Gels)

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30 pages, 3340 KiB

Open AccessReview

Exosome-Integrated Hydrogels for Bone Tissue Engineering

by Hee Sook Hwang and Chung-Sung Lee

Gels 2024, 10(12), 762; https://doi.org/10.3390/gels10120762 - 23 Nov 2024

Abstract

Exosome-integrated hydrogels represent a promising frontier in bone tissue engineering, leveraging the unique biological properties of exosomes to enhance the regenerative capabilities of hydrogels. Exosomes, as naturally occurring extracellular vesicles, carry a diverse array of bioactive molecules that play critical roles in intercellular [...] Read more.

Exosome-integrated hydrogels represent a promising frontier in bone tissue engineering, leveraging the unique biological properties of exosomes to enhance the regenerative capabilities of hydrogels. Exosomes, as naturally occurring extracellular vesicles, carry a diverse array of bioactive molecules that play critical roles in intercellular communication and tissue regeneration. When combined with hydrogels, these exosomes can be spatiotemporally delivered to target sites, offering a controlled and sustained release of therapeutic agents. This review aims to provide a comprehensive overview of the recent advancements in the development, engineering, and application of exosome-integrated hydrogels for bone tissue engineering, highlighting their potential to overcome current challenges in tissue regeneration. Furthermore, the review explores the mechanistic pathways by which exosomes embedded within hydrogels facilitate bone repair, encompassing the regulation of inflammatory pathways, enhancement of angiogenic processes, and induction of osteogenic differentiation. Finally, the review addresses the existing challenges, such as scalability, reproducibility, and regulatory considerations, while also suggesting future directions for research in this rapidly evolving field. Thus, we hope this review contributes to advancing the development of next-generation biomaterials that synergistically integrate exosome and hydrogel technologies, thereby enhancing the efficacy of bone tissue regeneration. Full article

(This article belongs to the Special Issue Recent Advances in Hydrogels for Biomedical Application (2nd Edition))

20 pages, 2931 KiB

Open AccessArticle

Development of Soft Wrinkled Micropatterns on the Surface of 3D-Printed Hydrogel-Based Scaffolds via High-Resolution Digital Light Processing

by Mauricio A. Sarabia-Vallejos, Scarleth Romero De la Fuente, Nicolás A. Cohn-Inostroza, Claudio A. Terraza, Juan Rodríguez-Hernández and Carmen M. González-Henríquez

Gels 2024, 10(12), 761; https://doi.org/10.3390/gels10120761 - 23 Nov 2024

Abstract

The preparation of sophisticated hierarchically structured and cytocompatible hydrogel scaffolds is presented. For this purpose, a photosensitive resin was developed, printability was evaluated, and the optimal conditions for 3D printing were investigated. The design and fabrication by additive manufacturing of tailor-made porous scaffolds [...] Read more.

The preparation of sophisticated hierarchically structured and cytocompatible hydrogel scaffolds is presented. For this purpose, a photosensitive resin was developed, printability was evaluated, and the optimal conditions for 3D printing were investigated. The design and fabrication by additive manufacturing of tailor-made porous scaffolds were combined with the formation of surface wrinkled micropatterns. This enabled the combination of micrometer-sized channels (100–200 microns) with microstructured wrinkled surfaces (1–3 μm wavelength). The internal pore structure was found to play a critical role in the mechanical properties. More precisely, the TPMS structure with a zero local curvature appears to be an excellent candidate for maintaining its mechanical resistance to compression stress, thus retaining its structural integrity upon large uniaxial deformations up to 70%. Finally, the washing conditions selected enabled us to produce noncytotoxic materials, as evidenced by experiments using AlamarBlue to follow the metabolic activity of the cells. Full article

(This article belongs to the Special Issue Advanced Soft Gels with Enhanced Functionality for Biomedical and Additive Manufacturing Applications)

15 pages, 2878 KiB

Open AccessArticle

Development of Variable Charge Cationic Hydrogel Particles with Potential Application in the Removal of Amoxicillin and Sulfamethoxazole from Water

by Francisca L. Aranda, Manuel F. Meléndrez, Mónica A. Pérez, Bernabé L. Rivas, Eduardo D. Pereira and Daniel A. Palacio

Gels 2024, 10(12), 760; https://doi.org/10.3390/gels10120760 - 23 Nov 2024

Abstract

Cationic hydrogel particles (CHPs) crosslinked with glutaraldehyde were synthesized and characterized to evaluate their removal capacity for two globally consumed antibiotics: amoxicillin and sulfamethoxazole. The obtained material was characterized by FTIR, SEM, and TGA, confirming effective crosslinking. The optimal working pH was determined [...] Read more.

Cationic hydrogel particles (CHPs) crosslinked with glutaraldehyde were synthesized and characterized to evaluate their removal capacity for two globally consumed antibiotics: amoxicillin and sulfamethoxazole. The obtained material was characterized by FTIR, SEM, and TGA, confirming effective crosslinking. The optimal working pH was determined to be 6.0 for amoxicillin and 4.0 for sulfamethoxazole. Under these conditions, the CHPs achieved over 90.0% removal of amoxicillin after 360 min at room temperature, while sulfamethoxazole removal reached approximately 60.0% after 300 min. Thermodynamic analysis indicated that adsorption occurs through a physisorption process and is endothermic. The ΔH° values of 28.38 kJ mol⁻¹, 12.39 kJ mol⁻¹, and ΔS° 97.19 J mol⁻¹ K⁻¹, and 33.94 J mol⁻¹ K⁻¹ for AMX and SMX, respectively. These results highlight the potential of CHPs as promising materials for the removal of such contaminants from aqueous media. Full article

(This article belongs to the Special Issue Designing Hydrogels and Hydrogel-Derived Materials for Agriculture and Water Sustainability)

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17 pages, 4167 KiB

Open AccessArticle

3D Printing of New Foods Using Cellulose-Based Gels Obtained from Cerotonia siliqua L. Byproducts

by Antoni Capellà, Mónica Umaña, Esperanza Dalmau, Juan A. Cárcel and Antoni Femenia

Gels 2024, 10(12), 759; https://doi.org/10.3390/gels10120759 - 23 Nov 2024

Abstract

Carob pulp is a valuable source of cellulose-rich fraction (CRF) for many food applications. This study aimed to obtain and characterize a CRF derived from carob pulp waste after sugar removal and to evaluate its potential use in the 3D printing of cellulose-rich [...] Read more.

Carob pulp is a valuable source of cellulose-rich fraction (CRF) for many food applications. This study aimed to obtain and characterize a CRF derived from carob pulp waste after sugar removal and to evaluate its potential use in the 3D printing of cellulose-rich foods. Thus, the extraction of the CRF present in carob pulp (by obtaining the alcohol-insoluble residue) was carried out, accounting for nearly 45% dm (dry matter) of this byproduct. The CRF contained about 24% dm of cellulose. The functional properties (swelling capacity, water retention, and fat adsorption) related to this fraction were determined, showing a value of 5.9 mL/g of CRF and 4.0 and 6.5 g/g of CRF, respectively. Different gels were formulated with a total solids content of 15% wm (wet matter), using potato peel flour as a base and partially substituting with CRF (0% to 8% wm). The cellulose-based gels were characterized in terms of viscosity, water distribution (low-field Nuclear Magnetic Resonance), and printability, while the 3D printed samples were assessed for their textural properties. As the percentage of added CRF increased, the viscosity decreased while the water retention increased. Printability improved when small proportions of CRF (2% to 4%) were used, while it deteriorated for higher percentages (6% to 8%). The textural properties (hardness, adhesiveness, cohesiveness, and gumminess) showed significant changes caused by the addition of CRF, with gels containing 3% to 4% CRF exhibiting the most suitable printing values. In summary, this study demonstrates the significant potential of carob cellulose-based gel as an ingredient in the 3D printing of novel fiber-rich foods, contributing to reducing food waste and promoting sustainable practices within the framework of the circular economy. Full article

(This article belongs to the Special Issue Cellulose-Based Gels: Synthesis, Properties, and Applications)

17 pages, 7663 KiB

Open AccessArticle

Preparation and Characterization of Poly(acrylic acid-co-vinyl imidazole) Hydrogel-Supported Palladium Catalyst for Tsuji–Trost and Suzuki Reactions in Aqueous Media

by Huijun Song, Amatjan Sawut, Rena Simayi and Yuqi Sun

Gels 2024, 10(12), 758; https://doi.org/10.3390/gels10120758 - 23 Nov 2024

Abstract

In this study, a novel polyacrylate-co-vinyl imidazole hydrogel-supported palladium (Pd) catalyst (P(AA-co-VI)@Pd) was prepared through heat-initiated polymerization, starting with the formation of a complex between vinyl imidazole and palladium chloride, followed by the addition of 75% neutralized acrylic acid (AA), crosslinking agent, and [...] Read more.

In this study, a novel polyacrylate-co-vinyl imidazole hydrogel-supported palladium (Pd) catalyst (P(AA-co-VI)@Pd) was prepared through heat-initiated polymerization, starting with the formation of a complex between vinyl imidazole and palladium chloride, followed by the addition of 75% neutralized acrylic acid (AA), crosslinking agent, and initiator. The structure and morphology of the catalyst were characterized using ICP-OES, SEM, EDX, Mapping, FT-IR, TGA, XRD, XPS and TEM techniques. It was confirmed that the catalyst exhibited excellent compatibility with water solvent and uniform distribution of Pd. The P(AA-co-VI)@Pd hydrogel catalyst demonstrated remarkable catalytic activity and ease of separation. Notably, in a Tsuji–Trost reaction, employing water as the solvent, it achieved a conversion rate as high as 94% at very low catalyst dosages, indicating its superior catalytic performance. Moreover, after six consecutive cycles, the catalyst maintained good activity and structural stability, highlighting its exceptional reusability and environmental friendliness. Furthermore, the outstanding efficiency of the catalyst was also observed in a Suzuki coupling reaction where both conversion rate and yield reached 100% and 99%, respectively, within just one hour reaction time, thus further validating its universality and efficacy across various chemical reactions. Full article

(This article belongs to the Special Issue Gel-Based Materials: Preparations and Characterization (2nd Edition))

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15 pages, 3295 KiB

Open AccessArticle

Electrostatic Gelatin Nanoparticles for Biotherapeutic Delivery

by Connor Tobo, Avantika Jain, Madhushika Elabada Gamage, Paul Jelliss and Koyal Garg

Gels 2024, 10(12), 757; https://doi.org/10.3390/gels10120757 - 23 Nov 2024

Abstract

Biological agents such as extracellular vesicles (EVs) and growth factors, when administered in vivo, often face rapid clearance, limiting their therapeutic potential. To address this challenge and enhance their efficacy, we propose the electrostatic conjugation and sequestration of these agents into gelatin-based biomaterials. [...] Read more.

Biological agents such as extracellular vesicles (EVs) and growth factors, when administered in vivo, often face rapid clearance, limiting their therapeutic potential. To address this challenge and enhance their efficacy, we propose the electrostatic conjugation and sequestration of these agents into gelatin-based biomaterials. In this study, gelatin nanoparticles (GNPs) were synthesized via the nanoprecipitation method, with adjustments to the pH of the gelatin solution (4.0 or 10.0) to introduce either a positive or negative charge to the nanoparticles. The GNPs were characterized using dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM) imaging. Both positively and negatively charged GNPs were confirmed to be endotoxin-free and non-cytotoxic. Mesenchymal stem cell (MSC)-derived EVs exhibited characteristic surface markers and a notable negative charge. Zeta potential measurements validated the electrostatic conjugation of MSC-EVs with positively charged GNPs. Utilizing a transwell culture system, we evaluated the impact of EV-GNP conjugates encapsulated within a gelatin hydrogel on macrophage secretory activity. The results demonstrated the bioactivity of EV-GNP conjugates and their synergistic effect on macrophage secretome over five days of culture. In summary, these findings demonstrate the efficacy of electrostatically coupled biotherapeutics with biomaterials for tissue regeneration applications. Full article

(This article belongs to the Special Issue Hydrogel for Tissue Engineering and Biomedical Therapeutics)

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15 pages, 6312 KiB

Open AccessArticle

Environmentally Friendly Nanoporous Polymeric Gels for Sustainable Wastewater Treatment

by Tarek M. Madkour, Rasha E. Elsayed and Rasha A. Azzam

Gels 2024, 10(12), 756; https://doi.org/10.3390/gels10120756 - 22 Nov 2024

Abstract

Environmentally friendly nanoporous gels are tailor-designed and employed in the adsorption of toxic organic pollutants in wastewater. To ensure the maximum adsorption of the contaminant molecules by the gels, molecular modeling techniques were used to evaluate the binding affinity between the toxic organic [...] Read more.

Environmentally friendly nanoporous gels are tailor-designed and employed in the adsorption of toxic organic pollutants in wastewater. To ensure the maximum adsorption of the contaminant molecules by the gels, molecular modeling techniques were used to evaluate the binding affinity between the toxic organic contaminants such as methylene blue (MB) and Congo red (CR) and various biopolymers. To generate nanopores in the matrix of the polymeric gels, salt crystals were used as porogen. The pores were then used to accommodate catalytic nickel (Ni⁰) nanoparticles. Under UV irradiation, the nanoparticles demonstrated the effective adsorption and photocatalytic degradation of both the methylene blue and Congo red dyes, achieving removal efficiencies of up to 90% for MB and 80% for CR. The thermodynamic analysis suggested a spontaneous endothermic dissociative adsorption mechanism, which implies the oxidative catalytic degradation of the dyes. The kinetic modeling suggested a pseudo-second-order model, while the model for intra-particle diffusion revealed that Congo red diffuses faster than methylene blue. MB adsorption followed a Langmuir isotherm, while CR adsorption followed a linear isotherm. The results confirm that dye molecules initially undergo physisorption and subsequent dissociative adsorption. The products of the catalytic degradation of methylene blue continue to be absorbed on the surface of the nanoparticles, while those of Congo red switch to preferential desorption. Full article

(This article belongs to the Special Issue Application of Hydrogels in Adsorption of Pollutants in Water and Wastewater Treatment)

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20 pages, 1695 KiB

Open AccessReview

Recent Advances of Cellulose-Based Hydrogels Combined with Natural Colorants in Smart Food Packaging

by Lan Yang, Qian-Yu Yuan, Ching-Wen Lou, Jia-Horng Lin and Ting-Ting Li

Gels 2024, 10(12), 755; https://doi.org/10.3390/gels10120755 - 21 Nov 2024

Abstract

Due to the frequent occurrence of food safety problems in recent years, healthy diets are gradually receiving worldwide attention. Chemical pigments are used in smart food packaging because of their bright colors and high visibility. However, due to shortcomings such as carcinogenicity, people [...] Read more.

Due to the frequent occurrence of food safety problems in recent years, healthy diets are gradually receiving worldwide attention. Chemical pigments are used in smart food packaging because of their bright colors and high visibility. However, due to shortcomings such as carcinogenicity, people are gradually looking for natural pigments to be applied in the field of smart food packaging. In traditional smart food packaging, the indicator and the packaging bag substrate have different degrees of toxicity. Smart food packaging that combines natural colorants and cellulose-based hydrogels is becoming more and more popular with consumers for being natural, non-toxic, environmentally friendly, and renewable. This paper reviews the synthesis methods and characteristics of cellulose-based hydrogels, as well as the common types and characteristics of natural pigments, and discusses the application of natural colorants and cellulose-based hydrogels in food packaging, demonstrating their great potential in smart food packaging. Full article

(This article belongs to the Special Issue Advances in Cellulose-Based Hydrogels (3rd Edition))

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25 pages, 8025 KiB

Open AccessReview

The Unfulfilled Potential of Synthetic and Biological Hydrogel Membranes in the Treatment of Abdominal Hernias

by Kenigen Manikion, Christodoulos Chrysanthou and Constantinos Voniatis

Gels 2024, 10(12), 754; https://doi.org/10.3390/gels10120754 - 21 Nov 2024

Abstract

Hydrogel membranes can offer a cutting-edge solution for abdominal hernia treatment. By combining favorable mechanical parameters, tissue integration, and the potential for targeted drug delivery, hydrogels are a promising alternative therapeutic option. The current review examines the application of hydrogel materials composed of [...] Read more.

Hydrogel membranes can offer a cutting-edge solution for abdominal hernia treatment. By combining favorable mechanical parameters, tissue integration, and the potential for targeted drug delivery, hydrogels are a promising alternative therapeutic option. The current review examines the application of hydrogel materials composed of synthetic and biological polymers, such as polyethylene glycol (PEG), polyvinyl alcohol (PVA), gelatine, and silk fibroin, in the context of hernia repair. Overall, this review highlights the current issues and prospects of hydrogel membranes as viable alternatives to the conventional hernia meshes. The emphasis is placed on the applicability of these hydrogels as components of bilayer systems and standalone materials. According to our research, hydrogel membranes exhibit several advantageous features relevant to hernia repair, such as a controlled inflammatory reaction, tissue integration, anti-adhesive-, and even thermoresponsive properties. Nevertheless, despite significant advancements in material science, the potential of hydrogel membranes seems neglected. Bilayer constructs have not transitioned to clinical trials, whereas standalone membranes seem unreliable due to the lack of comprehensive mechanical characterization and long-term in vivo experiments. Full article

(This article belongs to the Special Issue Biosoursed and Bioinspired Gels for Biomedical Applications (2nd Edition))

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23 pages, 10821 KiB

Open AccessArticle

Poly(Vinyl Alcohol) Drug and PVA–Drug–Surfactant Complex Organogel with Dimethyl Sulfoxide as a Drug Delivery System

by Sabina Otarbayeva and Dmitriy Berillo

Gels 2024, 10(11), 753; https://doi.org/10.3390/gels10110753 - 20 Nov 2024

Abstract

The relevance of active research lies in the need to develop new technologies to improve drug delivery methods for the effective treatment of wound healing. Additionally, the potential application of organogels in other areas of biomedicine, such as creating medical patches with controlled [...] Read more.

The relevance of active research lies in the need to develop new technologies to improve drug delivery methods for the effective treatment of wound healing. Additionally, the potential application of organogels in other areas of biomedicine, such as creating medical patches with controlled drug delivery, indicates a wide range of possibilities for using this technology. This study focuses on developing controlled drug delivery systems using organogels as carriers for ceftriaxone and ofloxacin. By selecting optimal formulations, organogels were created to immobilize the drugs, facilitating their effective and sustained release. The swelling behavior of the hydrogels was studied, showing a swelling coefficient between 16 and 32%, indicating their ability to absorb liquid relative to their weight. Drug release studies demonstrated that ceftriaxone was released 1.8 times slower than ofloxacin, ensuring a more controlled delivery. Microbiological tests confirmed that the organogels containing ofloxacin exhibited antimicrobial activity against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. However, it was a challenge to estimate activity for the model antibiotic ceftriaxone due to bacterial resistance to it. Organogel poly(vinyl alcohol) (PVA)-DMSO–alginate modifications with surfactant cetylpyridinium bromide led to the formation of a polyelectrolyte complex on the interphase, allowing further enhanced the prolonged release of the drugs. The research identified that the optimal compositions for sustained drug release were organogels with compositions PVA (10%)-PVP (1%) DMSO (50%) and PVA (10%)-DMSO (50%) formulations, illustrating the transparent nature of these organogels making them suitable for ophthalmological application. Various organogels compositions (PVA-DMSO, PVA-poly(vinylpyrrolidone)-DMSO, PVA-DMSO–alginate, PVA-DMSO-PLGA, PVA-DMSO–drug–surfactant) loaded with ceftriaxone, ofloxacin, and surfactant were prepared and characterized, highlighting their potential use in antibiotic patches for wound healing. These organogels illustrate promising results for localized treatment of infections in wounds, cuts, burns, and other skin lesions. Full article

(This article belongs to the Special Issue Advanced Hydrogels: Preparation, Property and Biomedical Application (2nd Edition))

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25 pages, 7612 KiB

Open AccessArticle

Development of Alginate Composite Microparticles for Encapsulation of Bifidobacterium animalis subsp. lactis

by Marko Vinceković, Lana Živković, Elmira Turkeyeva, Botagoz Mutaliyeva, Galiya Madybekova, Suzana Šegota, Nataša Šijaković Vujičić, Anđela Pustak, Tanja Jurkin, Marta Kiš and Sanja Kajić

Gels 2024, 10(11), 752; https://doi.org/10.3390/gels10110752 - 19 Nov 2024

Abstract

The probiotic bacterium Bifidobacterium animalis subsp. lactis BB-12 (BB-12) was encapsulated in two composites, alginate/agar and alginate/agar/casein. The network structure and physicochemical properties of these composites are influenced by complex interactions, including hydrogen bonding, electrostatic forces between biopolymers, calcium ions, and the encapsulated [...] Read more.

The probiotic bacterium Bifidobacterium animalis subsp. lactis BB-12 (BB-12) was encapsulated in two composites, alginate/agar and alginate/agar/casein. The network structure and physicochemical properties of these composites are influenced by complex interactions, including hydrogen bonding, electrostatic forces between biopolymers, calcium ions, and the encapsulated bacteria. The composites demonstrated a granular surface, with the granules being spatially oriented on the alginate/agar/BB-12 surface and linearly oriented on the alginate/agar/casein/BB-12 surface. They possess a highly organized microparticle structure and exhibit viscoelastic solid-like behavior. The alginate/agar/BB-12 composite showed higher storage modulus, shear stress, and shear strain values, indicating enhanced stability in various physical environments. Both composites displayed good thermal stability, aligning with their rheological properties, confirming their well-ordered structures. Despite differences in composite structures, the release mechanism of bacteria is governed by Fickian diffusion through the composite matrix. Based on physicochemical properties, the alginate/agar/casein composite is recommended for dairy product fermentation, while the alginate/agar composite seems more suitable for oral use. These findings provide new insights into the interactions between bacterial cultures and alginate composite ingredients. Full article

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20 pages, 3272 KiB

Open AccessArticle

Crosslinking by Click Chemistry of Hyaluronan Graft Copolymers Involving Resorcinol-Based Cinnamate Derivatives Leading to Gel-like Materials

by Mario Saletti, Simone Pepi, Marco Paolino, Jacopo Venditti, Germano Giuliani, Claudia Bonechi, Gemma Leone, Agnese Magnani, Claudio Rossi and Andrea Cappelli

Gels 2024, 10(11), 751; https://doi.org/10.3390/gels10110751 - 19 Nov 2024

Abstract

The well-known “click chemistry” reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) was used to transform under very mild conditions hyaluronan-based graft copolymers HA(270)-FA-Pg into the crosslinked derivatives HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL. In particular, medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted at [...] Read more.

The well-known “click chemistry” reaction copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) was used to transform under very mild conditions hyaluronan-based graft copolymers HA(270)-FA-Pg into the crosslinked derivatives HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL. In particular, medium molecular weight (i.e., 270 kDa) hyaluronic acid (HA) grafted at various extents (i.e., 10, 20, and 40%) with fluorogenic ferulic acid (FA) residue bonding propargyl groups were used in the CuAAC reaction with novel azido-terminated crosslinking agents Tri(Ethylene Glycol) Ethyl Resorcinol Acrylate (TEGERA) and Hexa(Ethylene Glycol) Ethyl Resorcinol Acrylate (HEGERA). The resulting HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL materials were characterized from the point of view of their structure by performing NMR studies. Moreover, the swelling behavior and rheological features were assessed employing TGA and DSC analysis to evaluate the potential gel-like properties of the resulting crosslinked materials. Despite the 3D crosslinked structure, HA(270)-FA-TEGERA-CL and HA(270)-FA-HEGERA-CL frameworks showed adequate swelling performance, the required shear thinning behavior, and coefficient of friction values close to those of the main commercial HA solutions used as viscosupplements (i.e., 0.20 at 10 mm/s). Furthermore, the presence of a crosslinked structure guaranteed a longer residence time. Indeed, HA(270)-FA-TEGERA-CL-40 and HA(270)-FA-HEGERA-CL-40 after 48 h showed a four times greater enzymatic resistance than the commercial viscosupplements. Based on the promising obtained results, the crosslinked materials are proposed for their potential applicability as novel viscosupplements. Full article

(This article belongs to the Special Issue Polymeric Hydrogels for Biomedical Application)

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