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Gels, Volume 9, Issue 1 (January 2023) – 71 articles

Cover Story (view full-size image): The design of novel polymeric materials for biomedical and technological applications with adequate mechanical properties and internal structures has been a field of intense research during the last few years. Among the different polymeric materials, hydrogels have received special attention due to their softness, high water content, response to certain stimuli and biocompatibility. Interestingly, hydrogels based on sodium alginate can be dehydrated under controlled stress, achieving permanent deformations due to the arising hydrogen bonds, which mechanically and structurally change the material. These changes also affect the responses of soft magnetic hydrogel actuators with potential biomedical and technological applications. View this paper
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17 pages, 2589 KiB  
Article
Drying of Hierarchically Organized Porous Silica Monoliths–Comparison of Evaporative and Supercritical Drying
by Richard Kohns, Jorge Torres-Rodríguez, Daniel Euchler, Malina Seyffertitz, Oskar Paris, Gudrun Reichenauer, Dirk Enke and Nicola Huesing
Gels 2023, 9(1), 71; https://doi.org/10.3390/gels9010071 - 16 Jan 2023
Cited by 4 | Viewed by 2230
Abstract
In this study, we present a detailed comparison between a conventional supercritical drying process and an evaporative drying technique for hierarchically organized porous silica gel monoliths. These gels are based on a model system synthesized by the aqueous sol–gel processing of an ethylene-glycol-modified [...] Read more.
In this study, we present a detailed comparison between a conventional supercritical drying process and an evaporative drying technique for hierarchically organized porous silica gel monoliths. These gels are based on a model system synthesized by the aqueous sol–gel processing of an ethylene-glycol-modified silane, resulting in a cellular, macroporous, strut-based network comprising anisotropic, periodically arranged mesopores formed by microporous amorphous silica. The effect of the two drying procedures on the pore properties (specific surface area, pore volume, and pore widths) and on the shrinkage of the monolith is evaluated through a comprehensive characterization by using nitrogen physisorption, electron microscopy, and small-angle X-ray scattering. It can clearly be demonstrated that for the hierarchically organized porous solids, the evaporative drying procedure can compete without the need for surface modification with the commonly applied supercritical drying in terms of the material and textural properties, such as specific surface area and pore volume. The thus obtained materials deliver a high specific surface area and exhibit overall comparable or even improved pore characteristics to monoliths prepared by supercritical drying. Additionally, the pore properties can be tailored to some extent by adjusting the drying conditions, such as temperature. Full article
(This article belongs to the Special Issue International Perspectives on Aerogels)
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21 pages, 2412 KiB  
Article
Biomedical Applications of Thermosensitive Hydrogels for Controlled/Modulated Piroxicam Delivery
by Snežana Ilić-Stojanović, Ljubiša Nikolić, Vesna Nikolić, Ivan Ristić, Suzana Cakić and Slobodan D. Petrović
Gels 2023, 9(1), 70; https://doi.org/10.3390/gels9010070 - 15 Jan 2023
Cited by 5 | Viewed by 1728
Abstract
The objectives of this study are the synthesis of thermosensitive poly(N-isopropylacrylamide-co-2-hydroxypropyl methacrylate), p(NiPAm-HPMet), hydrogels and the analysis of a drug-delivery system based on piroxicam, as a model drug, and synthesized hydrogels. A high pressure liquid chromatography method has been [...] Read more.
The objectives of this study are the synthesis of thermosensitive poly(N-isopropylacrylamide-co-2-hydroxypropyl methacrylate), p(NiPAm-HPMet), hydrogels and the analysis of a drug-delivery system based on piroxicam, as a model drug, and synthesized hydrogels. A high pressure liquid chromatography method has been used in order to determine both qualitative and quantitative amounts of unreacted monomers and crosslinkers from polymerized hydrogels. Swelling kinetics and the order of a swelling process of the hydrogels have been analyzed at 10 and 40 °C. The copolymers’ thermal properties have been monitored by the differential scanning calorimetry (DSC) method. DSC termograms have shown that melting occurs in two temperature intervals (142.36–150.72 °C and 153.14–156.49 °C). A matrix system with incorporated piroxicam has been analyzed by using FTIR and SEM methods. Structural analysis has demonstrated that intermolecular non-covalent interactions have been built between side-groups of copolymer and loaded piroxicam. Morphology of p(NiPAm-HPMet) after drug incorporation indicates the piroxicam presence into the copolymer pores. Kinetic parameters of the piroxicam release from hydrogels at 37 °C and pH 7.4 indicate that the fluid transport mechanism corresponds to Fickian diffusion. As a result, formulation of thermosensitive p(NiPAm-HPMet) hydrogels with incorporated piroxicam could be of interest for further testing as a drug carrier for modulated and prolonged release, especially for topical administration. Full article
(This article belongs to the Special Issue Hydrogels as Controlled Drug Delivery Systems)
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20 pages, 8386 KiB  
Article
Synthesis and Characteristics of a pH-Sensitive Sol-Gel Transition Colloid for Coal Fire Extinguishing
by Yiru Wang, Qinglin Zheng, Hetao Su, Zijun Huang and Gengyu Wang
Gels 2023, 9(1), 69; https://doi.org/10.3390/gels9010069 - 14 Jan 2023
Cited by 3 | Viewed by 1526
Abstract
Coal fires, most of which are triggered by the spontaneous combustion of coal, cause a huge waste of resources and release poisonous and harmful substances into the environment, seriously threatening the safety of industrial production. Gel flame retardant plays a core role in [...] Read more.
Coal fires, most of which are triggered by the spontaneous combustion of coal, cause a huge waste of resources and release poisonous and harmful substances into the environment, seriously threatening the safety of industrial production. Gel flame retardant plays a core role in coal fire prevention and extinguishing. Most gel flame retardants used in coal fires possess good sealing and oxygen isolation properties, but it is difficult for them to flow deep into fire areas due to their low fluidity. Some fire extinguishing agents with good fluidity lack leak-blocking performance. In order to simultaneously improve the fluidity, leakage sealing, and oxygen isolation effects of coal fire extinguishing colloids, a novel, pH-sensitive, sol-gel transition colloid was prepared using low methoxyl pectin (LMP), calcium bentonite (Ca-Bt), sodium bentonite (Na-Bt), and water as the main components. When the initial sol-state colloid absorbed acid gas products from coal combustion, the pH value decreased and a large amount of Ca2+ in Ca-Bt precipitated, thus immediately growing calcium bridges with LMP molecules that formed a three-dimensional network structure for gelation. The optimum ratio of the new colloid was determined through X-ray diffraction, tube inversion, shock shear-temperature scanning, and genetic algorithm. By testing the fire extinguishing performance of the colloid, the findings proved that the product had good oxygen isolation performance, strong adhesion ability, high thermal stability, and strong inhibition effects on coal combustion. Full article
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26 pages, 4986 KiB  
Review
Binary Hydrogels: Induction Methods and Recent Application Progress as Food Matrices for Bioactive Compounds Delivery—A Bibliometric Review
by Adonis Hilal, Anna Florowska and Małgorzata Wroniak
Gels 2023, 9(1), 68; https://doi.org/10.3390/gels9010068 - 14 Jan 2023
Cited by 7 | Viewed by 2534
Abstract
Food hydrogels are biopolymeric materials made from food-grade biopolymers with gelling properties (proteins and polysaccharides) and a 3D network capable of incorporating large amounts of water. They have sparked considerable interest because of their potential and broad application range in the biomedical and [...] Read more.
Food hydrogels are biopolymeric materials made from food-grade biopolymers with gelling properties (proteins and polysaccharides) and a 3D network capable of incorporating large amounts of water. They have sparked considerable interest because of their potential and broad application range in the biomedical and pharmaceutical sectors. However, hydrogel research in the field of food science is still limited. This knowledge gap provides numerous opportunities for implementing their unique properties, such as high water-holding capacity, moderated texture, compatibility with other substances, cell biocompatibility, biodegradability, and high resemblance to living tissues, for the development of novel, functional food matrices. For that reason, this article includes a bibliometric analysis characterizing research trends in food protein–polysaccharide hydrogels (over the last ten years). Additionally, it characterizes the most recent developments in hydrogel induction methods and the most recent application progress of hydrogels as food matrices as carriers for the targeted delivery of bioactive compounds. Finally, this article provides a future perspective on the need to evaluate the feasibility of using plant-based proteins and polysaccharides to develop food matrices that protect nutrients, including bioactive substances, throughout processing, storage, and digestion until they reach the specific targeted area of the digestive system. Full article
(This article belongs to the Special Issue Novel Gels for Food Product Development)
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21 pages, 7946 KiB  
Article
Structure-Related Mechanical Properties and Bioactivity of Silica–Gelatin Hybrid Aerogels for Bone Regeneration
by María V. Reyes-Peces, Rafael Fernández-Montesinos, María del Mar Mesa-Díaz, José Ignacio Vilches-Pérez, Jose Luis Cárdenas-Leal, Nicolás de la Rosa-Fox, Mercedes Salido and Manuel Piñero
Gels 2023, 9(1), 67; https://doi.org/10.3390/gels9010067 - 14 Jan 2023
Cited by 4 | Viewed by 1863
Abstract
We report the synthesis of mesoporous silica–gelatin hybrid aerogels with 15, 25, and 30 wt. % gelatin contents, using 3-glycidoxypropyl trimethoxysilane (GPTMS) as a coupling agent, for tissue-engineering applications. Aerogels were obtained using a one-step sol–gel process followed by CO2 supercritical drying, [...] Read more.
We report the synthesis of mesoporous silica–gelatin hybrid aerogels with 15, 25, and 30 wt. % gelatin contents, using 3-glycidoxypropyl trimethoxysilane (GPTMS) as a coupling agent, for tissue-engineering applications. Aerogels were obtained using a one-step sol–gel process followed by CO2 supercritical drying, resulting in crack-free monolith samples with bulk densities ranging from 0.41 g cm−3 to 0.66 g cm−3. Nitrogen adsorption measurements revealed an interconnected mesopore network and a general decrease in the textural parameters: specific surface areas (651–361 m2 g−1), pore volume (1.98–0.89 cm3 g−1), and pore sizes (10.8–8.6 nm), by increasing gelatin content. Thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy and uniaxial compression experiments confirmed that the structure, thermal properties and mechanical behavior of these aerogels changed significantly when the concentration of gelatin reached 25 wt.%, suggesting that this composition corresponds to the percolation threshold of the organic phase. In addition, the samples exhibited hydrophilic behavior and extremely fast swelling in phosphate-buffered saline (PBS), with swelling ratios from 2.32 to 3.32. Furthermore, in vitro bioactivity studies revealed a strong relationship between the kinetics of the nucleation and growth processes of hydroxyapatite in simulated body fluid (SBF) and the gelatin content. The live/dead assay revealed no cytotoxicity in HOB® osteoblasts in vitro and a positive influence on cell growth, focal adhesion development, and cytoskeletal arrangement for cell adhesion. Mineralization assays confirmed the positive effects of the samples on osteoblast differentiation. The biomaterials described are versatile, can be easily sterilized and are suitable for a wide range of applications in bone tissue-engineering, either alone or in combination with bioactive-reinforced phases. Full article
(This article belongs to the Special Issue International Perspectives on Aerogels)
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9 pages, 1829 KiB  
Article
New Paradigm in Diabetic Foot Ulcer Grafting Techniques Using 3D-Bioprinted Autologous Minimally Manipulated Homologous Adipose Tissue (3D-AMHAT) with Fibrin Gel Acting as a Biodegradable Scaffold
by Mohd Yazid Bajuri, Jeehee Kim, Yeongseo Yu and Muhammad Shazwan Shahul Hameed
Gels 2023, 9(1), 66; https://doi.org/10.3390/gels9010066 - 13 Jan 2023
Cited by 3 | Viewed by 4378
Abstract
Adipose tissue is an abundant source of extracellular substances that support the tissue repair process. This pilot study was carried out to determine the efficacy of 3D-bioprinted autologous adipose tissue grafts on diabetic foot ulcers (DFUs), with fibrin gel used to stabilise the [...] Read more.
Adipose tissue is an abundant source of extracellular substances that support the tissue repair process. This pilot study was carried out to determine the efficacy of 3D-bioprinted autologous adipose tissue grafts on diabetic foot ulcers (DFUs), with fibrin gel used to stabilise the graft. This was a single-arm pilot study in a tertiary hospital that provides diabetic wound care services. A total of 10 patients with a DFU were enrolled, and the primary endpoint was complete healing within 12 weeks. The secondary endpoints were wound size reduction, time to healing, and adverse events. Seven out of ten patients showed complete healing of their DFU within 12 weeks (at 2, 4, 5, 10, and 12 weeks, respectively). The wound size reduction rate was significantly and progressively reduced over time. According to our data, autologous adipose tissue grafting using a 3D bioprinter, with the addition of fibrin gel that acts as a scaffold, promotes wound healing with high-quality skin reconstruction. Throughout this study period, no adverse events were observed. Full article
(This article belongs to the Special Issue Hydrogel-Based Scaffolds with a Focus on Medical Use)
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10 pages, 4630 KiB  
Communication
Effect of Grape Seed Extract on Gelatin-Based Edible 3D-Hydrogels for Cultured Meat Application
by Kummara Madhusudana Rao, Hyeon Jin Kim, Soyeon Won, Soon Mo Choi and Sung Soo Han
Gels 2023, 9(1), 65; https://doi.org/10.3390/gels9010065 - 12 Jan 2023
Cited by 4 | Viewed by 2427
Abstract
Cell-cultured meat, which is artificial meat made by in vitro cultivation of animal-derived cells, has attracted a lot of interest as a potential source of protein in the future. Porous hydrogels are crucial components that can be used as an artificial extracellular matrix [...] Read more.
Cell-cultured meat, which is artificial meat made by in vitro cultivation of animal-derived cells, has attracted a lot of interest as a potential source of protein in the future. Porous hydrogels are crucial components that can be used as an artificial extracellular matrix (ECM) to provide cell growth for generating cultured meat. In this study, we highlight the effects of grape seed extract (proanthocyanidins, PC) on the physicochemical and biological functions (bovine satellite muscle cell (BSC) growth and adhesion) of an edible gelatin (GL)-based hydrogel. The freeze-dried hydrogels had good compressive characteristics with pore sizes ranging from 100 to 300 μm. BSCs were able to grow and attach to porous GL-PC hydrogels. These studies suggested that the developed hydrogels using edible materials and made by employing a low-cost method may serve in the cell growth of muscle cells for cultured meat applications. Full article
(This article belongs to the Special Issue Innovative Biopolymer-Based Hydrogels)
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15 pages, 5346 KiB  
Article
Facile Synthesis and Fabrication of NIPAM-Based Cryogels for Environmental Remediation
by Jaweria Ambreen, Abdul Haleem, Aqeel Ahmed Shah, Fozia Mushtaq, Muhammad Siddiq, Muhammad Ali Bhatti, Syed Nizam Uddin Shah Bukhari, Ali Dad Chandio, Wael A. Mahdi and Sultan Alshehri
Gels 2023, 9(1), 64; https://doi.org/10.3390/gels9010064 - 12 Jan 2023
Cited by 15 | Viewed by 2317
Abstract
Herein, polymeric cryogels containing poly(N-isopropylacrylamide) were synthesized by cryo-polymerization at subzero temperature. The synthesized cryogels were loaded with silver and palladium nanoparticles by the chemical reduction method at room temperature using the reducing agent NaBH4. Moreover, for comparison with cryogels, pure [...] Read more.
Herein, polymeric cryogels containing poly(N-isopropylacrylamide) were synthesized by cryo-polymerization at subzero temperature. The synthesized cryogels were loaded with silver and palladium nanoparticles by the chemical reduction method at room temperature using the reducing agent NaBH4. Moreover, for comparison with cryogels, pure poly(N-isopropylacrylamide) hydrogel and its silver hybrid were also prepared by the conventional method at room temperature. The chemical structure and functional group analysis of the pure cryogels was confirmed by Fourier transform infrared spectroscopy. The synthesis of hybrid cryogels was confirmed by the X-ray diffraction technique and energy dispersive X-ray. The pore size and surface morphology of the pure cryogels, their respective hybrid cryogels and of conventional hydrogels were studied by using the scanning electron microscopy technique. The hybrid cryogels were successfully used as a catalyst for the degradation of methyl orange dye. The degradation performance of the hybrid cryogels was much better than its counterpart hybrid hydrogel for methyl orange dye. The effect of temperature and amount of catalyst on catalytic performance was studied by UV-visible spectroscopy. The reduction follows pseudo-first-order reaction kinetics. In addition, the antibacterial activities of these cryogels were evaluated against Gram-positive bacteria (Staphylococcus aureus, ATCC: 2593) and Gram-negative bacteria (Escherichia coli, ATCC: 25922). Both hybrid cryogels have shown much better antibacterial activity for these two strains of bacteria compared to pure cryogels. The results indicate that these cryogels are potential candidates for water purification systems as well as biomedical applications. Full article
(This article belongs to the Special Issue Recent Advances in Polymeric Cryogels)
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17 pages, 2824 KiB  
Article
Influence of Cross-Linking Conditions on Drying Kinetics of Alginate Hydrogel
by Magdalena B. Łabowska, Maria Skrodzka, Hanna Sicińska, Izabela Michalak and Jerzy Detyna
Gels 2023, 9(1), 63; https://doi.org/10.3390/gels9010063 - 12 Jan 2023
Cited by 11 | Viewed by 2369
Abstract
Hydrogels are three-dimensional cross-linked polymeric networks capable of a large amount of fluid retention in their structure. Hydrogel outputs manufactured using additive manufacturing technologies are exposed to water loss, which may change their original shape and dimensions. Therefore, the possibility of retaining water [...] Read more.
Hydrogels are three-dimensional cross-linked polymeric networks capable of a large amount of fluid retention in their structure. Hydrogel outputs manufactured using additive manufacturing technologies are exposed to water loss, which may change their original shape and dimensions. Therefore, the possibility of retaining water is important in such a structure. In this manuscript, kinetic analysis of water evaporation from sodium alginate-based hydrogels exposed to different environmental conditions such as different temperatures (7 and 23 °C) and ambient humidity (45, 50 and 95%) has been carried out. The influence of the cross-linking method (different calcium chloride concentration—0.05, 0.1 and 0.5 M) of sodium alginate and cross-linking time on the water loss was also considered. Studies have shown that a decrease in the temperature and increase in the storage humidity can have a positive effect on the water retention in the structure. The storage conditions that led to the least weight and volume loss were T 7 °C and 95% humidity. These experiments may help in selecting the appropriate hydrogel preparation method for future applications, as well as their storage conditions for minimum water loss and, consequently, the least change in dimensions and shape. Full article
(This article belongs to the Special Issue Gel Bioinks)
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12 pages, 3797 KiB  
Article
Optimising Soy and Pea Protein Gelation to Obtain Hydrogels Intended as Precursors of Food-Grade Dried Porous Materials
by Lorenzo De Berardinis, Stella Plazzotta and Lara Manzocco
Gels 2023, 9(1), 62; https://doi.org/10.3390/gels9010062 - 12 Jan 2023
Cited by 6 | Viewed by 3346
Abstract
Dried porous materials based on plant proteins are attracting large attention thanks to their potential use as sustainable food ingredients. Nevertheless, plant proteins present lower gelling properties than animal ones. Plant protein gelling could be improved by optimising gelation conditions by acting on [...] Read more.
Dried porous materials based on plant proteins are attracting large attention thanks to their potential use as sustainable food ingredients. Nevertheless, plant proteins present lower gelling properties than animal ones. Plant protein gelling could be improved by optimising gelation conditions by acting on protein concentration, pH, and ionic strength. This work aimed to systematically study the effect of these factors on the gelation behaviour of soy and pea protein isolates. Protein suspensions having different concentrations (10, 15, and 20% w/w), pH (3.0, 4.5, 7.0), and ionic strength (IS, 0.0, 0.6, 1.5 M) were heat-treated (95 °C for 15 min) and characterised for rheological properties and physical stability. Strong hydrogels having an elastic modulus (G′) higher than 103 Pa and able to retain more than 90% water were only obtained from suspensions containing at least 15% soy protein, far from the isoelectric point and at an IS above 0.6 M. By contrast, pea protein gelation was achieved only at a high concentration (20%), and always resulted in weak gels, which showed increasing G′ with the increase in pH and IS. Results were rationalised into a map identifying the gelation conditions to modulate the rheological properties of soy and pea protein hydrogels, for their subsequent conversion into xerogels, cryogels, and aerogels. Full article
(This article belongs to the Special Issue Advances in Xerogels: From Design to Applications)
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13 pages, 752 KiB  
Article
Kaniwa (Chenopodium pallidicaule)’s Nutritional Composition and Its Applicability as an Elder-Friendly Food with Gelling Agents
by Dah-Sol Kim and Fumiko Iida
Gels 2023, 9(1), 61; https://doi.org/10.3390/gels9010061 - 12 Jan 2023
Viewed by 1603
Abstract
(1) Background: This study attempted to develop an elder-friendly food suitable to the Korean Industrial Standard (KS) after identifying the nutritional characteristics of Kaniwa; (2) Methods: The nutrient composition and physiological activity of Kaniwa were analyzed, and the concentration of the gelling agent [...] Read more.
(1) Background: This study attempted to develop an elder-friendly food suitable to the Korean Industrial Standard (KS) after identifying the nutritional characteristics of Kaniwa; (2) Methods: The nutrient composition and physiological activity of Kaniwa were analyzed, and the concentration of the gelling agent (guar gum, locust bean gum, and xanthan gum) to be added to Kaniwa mousse was derived through regression analysis to suit KS hardness level 1 to 3; (3) Results: It was found that Kaniwa not only had a good fatty acid composition but also had good antioxidant and anti-diabetic properties. Moreover, it was found that in order to have the hardness to chew Kaniwa mousse with the tongue, it was necessary to add less than 1.97% guar gum, 4.03% locust bean gum, and 8.59% xanthan gum. In order to have a hardness that can be chewed with the gum, it was found that 2.17~4.97% guar gum, 4.45~10.28% locust bean gum, and 9.48~21.96% xanthan gum should be added; (4) Conclusions: As the aging rate and life expectancy increase, support for developmental research related to the elder-friendly industry should be continuously expanded in preparation for the upcoming super-aging society. Full article
(This article belongs to the Special Issue Recent Advances in Food Gels)
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24 pages, 7384 KiB  
Article
Development and Evaluation of Cellulose Derivative and Pectin Based Swellable pH Responsive Hydrogel Network for Controlled Delivery of Cytarabine
by Nighat Batool, Rai Muhammad Sarfraz, Asif Mahmood, Umaira Rehman, Muhammad Zaman, Shehla Akbar, Diena M. Almasri and Heba A. Gad
Gels 2023, 9(1), 60; https://doi.org/10.3390/gels9010060 - 12 Jan 2023
Cited by 6 | Viewed by 2252
Abstract
In the present study, pH-sensitive, biodegradable, and biocompatible Na-CMC/pectin poly(methacrylic acid) hydrogels were synthesized using an aqueous free radical polymerization technique and encapsulated by cytarabine (anti-cancer drug). The aim of the project was to sustain the plasma profile of cytarabine through oral administration. [...] Read more.
In the present study, pH-sensitive, biodegradable, and biocompatible Na-CMC/pectin poly(methacrylic acid) hydrogels were synthesized using an aqueous free radical polymerization technique and encapsulated by cytarabine (anti-cancer drug). The aim of the project was to sustain the plasma profile of cytarabine through oral administration. Sodium carboxymethyl cellulose (Na-CMC) and pectin were cross-linked chemically with methacrylic acid (MAA) as a monomer, using methylene bisacrylamide (MBA) as cross-linker and ammonium per sulfate (APS) as an initiator. Prepared hydrogel formulations were characterized for their texture, morphology, cytarabine loading efficiency, compositional and structural properties, thermal nature, stability, swelling response, drug release profile (pH 1.2 and pH 7.4), and in-vivo pharmacokinetic evaluation. Cytarabine-loaded hydrogels were also evaluated for their safety profile by carrying out toxicity studies in rabbits. Results demonstrated efficient encapsulation of cytarabine into the prepared network with loading ranging from 48.5–82.3%. The highest swelling ratio of 39.38 and maximum drug release of 83.29–85.27% were observed at pH 7.4, highlighting the pH responsiveness of the grafted system. Furthermore, cytarabine maximum release was noticed over 24 h, ensuring a sustained release response for all formulations. Histopathological studies and hemolytic profiles confirmed that the prepared hydrogel system was safe, biocompatible, and non-irritant, showing no symptoms of any toxicities and degeneration in organs. Moreover, pharmacokinetic estimation of the cytarabine-loaded hydrogel showed a remarkable increase in the plasma half-life from 4.44 h to 9.24 h and AUC from 22.06 μg/mL.h to 56.94 μg/mL.h. This study revealed that the prepared hydrogel carrier system has excellent abilities in delivering the therapeutic moieties in a controlled manner. Full article
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23 pages, 3450 KiB  
Article
Design of Injectable Bioartificial Hydrogels by Green Chemistry for Mini-Invasive Applications in the Biomedical or Aesthetic Medicine Fields
by Rossella Laurano, Monica Boffito, Claudio Cassino, Francesco Liberti, Gianluca Ciardelli and Valeria Chiono
Gels 2023, 9(1), 59; https://doi.org/10.3390/gels9010059 - 11 Jan 2023
Cited by 5 | Viewed by 2111
Abstract
Bioartificial hydrogels are hydrophilic systems extensively studied for regenerative medicine due to the synergic combination of features of synthetic and natural polymers. Injectability is another crucial property for hydrogel mini-invasive administration. This work aimed at engineering injectable bioartificial in situ cross-linkable hydrogels by [...] Read more.
Bioartificial hydrogels are hydrophilic systems extensively studied for regenerative medicine due to the synergic combination of features of synthetic and natural polymers. Injectability is another crucial property for hydrogel mini-invasive administration. This work aimed at engineering injectable bioartificial in situ cross-linkable hydrogels by implementing green and eco-friendly approaches. Specifically, the versatile poly(ether urethane) (PEU) chemistry was exploited for the development of an amphiphilic PEU, while hyaluronic acid was selected as natural component. Both polymers were functionalized to expose thiol and catechol groups through green water-based carbodiimide-mediated grafting reactions. Functionalization was optimized to maximize grafting yield while preserving group functionality. Then, polymer miscibility was studied at the macro-, micro-, and nano-scale, suggesting the formation of hydrogen bonds among polymeric chains. All hydrogels could be injected through G21 and G18 needles in a wide temperature range (4–25 °C) and underwent sol-to-gel transition at 37 °C. The addition of an oxidizing agent to polymer solutions did not improve the gelation kinetics, while it negatively affected hydrogel stability in an aqueous environment, suggesting the occurrence of oxidation-triggered polymer degradation. In the future, the bioartificial hydrogels developed herein could find application in the biomedical and aesthetic medicine fields as injectable formulations for therapeutic agent delivery. Full article
(This article belongs to the Special Issue Gel Role in the World of the Cosmetic Research)
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19 pages, 5135 KiB  
Article
Mechano-Chemical Effect of Gelatin- and HA-Based Hydrogels on Human Retinal Progenitor Cells
by Pierre C. Dromel, Deepti Singh, Alfredo Alexander-Katz, Motoichi Kurisawa, Myron Spector and Michael Young
Gels 2023, 9(1), 58; https://doi.org/10.3390/gels9010058 - 11 Jan 2023
Cited by 4 | Viewed by 1596
Abstract
Engineering matrices for cell therapy requires design criteria that include the ability of these materials to support, protect and enhance cellular behavior in vivo. The chemical and mechanical formulation of the biomaterials can influence not only target cell phenotype but also cellular differentiation. [...] Read more.
Engineering matrices for cell therapy requires design criteria that include the ability of these materials to support, protect and enhance cellular behavior in vivo. The chemical and mechanical formulation of the biomaterials can influence not only target cell phenotype but also cellular differentiation. In this study, we have demonstrated the effect of a gelatin (Gtn)—hyaluronic acid (HA) hydrogel on human retinal progenitor cells (hRPCs) and show that by altering the mechanical properties of the materials, cellular behavior is altered as well. We have created an interpenetrating network polymer capable of encapsulating hRPCs. By manipulating the stiffness of the hydrogel, the differentiation potential of the hRPCs was controlled. Interpenetrating network 75 (IPN 75; 75% HA) allowed higher expression of rod photoreceptor markers, whereas cone photoreceptor marker expression was found to be higher in IPN 50. In vivo testing of these living matrices performed in Long–Evans rats showed higher levels of rod photoreceptor marker expression when IPN 75 was injected versus IPN 50. These biomaterials mimic biological cues that are required to simulate the dynamic complexity of natural retinal ECM. These hydrogels can be used as a vehicle for cell delivery in vivo as well as for expansion and differentiation in an in vitro 3D system in a highly reproducible manner. Full article
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23 pages, 8595 KiB  
Article
Synthesis and Characterization of Zinc Oxide Nanoparticles Stabilized with Biopolymers for Application in Wound-Healing Mixed Gels
by Andrey V. Blinov, Maksim D. Kachanov, Alexey A. Gvozdenko, Andrey A. Nagdalian, Anastasiya A. Blinova, Zafar A. Rekhman, Alexey B. Golik, Dmitriy S. Vakalov, David G. Maglakelidze, Anzhela G. Nagapetova, Alexander D. Pokhilko and Irina V. Burkina
Gels 2023, 9(1), 57; https://doi.org/10.3390/gels9010057 - 11 Jan 2023
Cited by 18 | Viewed by 2663
Abstract
A method for the synthesis of ZnO nanoparticles (ZnO NPs) gels was developed. ZnO NPs were obtained through a sol–gel method with zinc acetate usage as a precursor. Optimization of the method of synthesis of ZnO NPs gel has been carried out. It [...] Read more.
A method for the synthesis of ZnO nanoparticles (ZnO NPs) gels was developed. ZnO NPs were obtained through a sol–gel method with zinc acetate usage as a precursor. Optimization of the method of synthesis of ZnO NPs gel has been carried out. It was observed that the most stable ZnO NPs gels are formed at room temperature, pH = 8 and molar concentration of zinc C(Zn2+) = 0.05–0.2 M. It was shown that the addition of polysaccharide significantly affects the rheological properties and microstructure of ZnO NPs gels. We found that the optimal polysaccharide for the synthesis of ZnO NPs gels is hydroxyethyl cellulose. It is shown that the microstructure of a gel of ZnO NPs stabilized with hydroxyethyl cellulose is represented by irregularly shaped particles that are assembled into aggregates, with sizes ranging from 150 to 1400 nm. A significant hysteresis region is observed in a gel of ZnO NPs stabilized with hydroxyethyl cellulose. The process of interaction of ZnO NPs with polysaccharides was investigated. It was shown that the interaction of ZnO NPs with polysaccharides occurs through a charged hydroxyl group. In the experiment, a sample of a gel of ZnO NPs modified with hydroxyethyl cellulose was tested. It was shown that the gel of ZnO NPs modified with hydroxyethyl cellulose has a pronounced regenerative effect on burn wounds, which is significantly higher than that of the control group and the group treated with a gel of ZnO microparticles (MPs) and hydroxyethyl cellulose. It is also shown that the rate of healing of burn wounds in animals treated with gel of ZnO nanoparticles with hydroxyethyl cellulose (group 3) is 16.23% higher than in animals treated with gel of ZnO microparticles with hydroxyethyl cellulose (group 2), and 24.33% higher than in the control group treated with hydroxyethyl cellulose. The average rate of healing of burn wounds for the entire experimental period in experimental animals of group 3 is 1.26 and 1.54 times higher than in animals of group 2 and control group, respectively. An experimental study of a gel of ZnO NPs modified with hydroxyethyl cellulose has shown the effectiveness of its use in modeling the healing of skin wounds through primary tension. Full article
(This article belongs to the Special Issue Innovative Biopolymer-Based Hydrogels)
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8 pages, 1708 KiB  
Article
Tuning of Optical Stopband Wavelength and Effective Bandwidth of Gel-Immobilized Colloidal Photonic Crystal Films
by Ami Amano and Toshimitsu Kanai
Gels 2023, 9(1), 56; https://doi.org/10.3390/gels9010056 - 11 Jan 2023
Cited by 1 | Viewed by 1696
Abstract
We show that both the optical stopband wavelength and effective bandwidth of films of gel-immobilized loosely packed colloidal photonic crystals can be controlled over a wide range. When the gelation reagent of the charge-stabilized colloidal crystals was photopolymerized under ultraviolet light using different [...] Read more.
We show that both the optical stopband wavelength and effective bandwidth of films of gel-immobilized loosely packed colloidal photonic crystals can be controlled over a wide range. When the gelation reagent of the charge-stabilized colloidal crystals was photopolymerized under ultraviolet light using different upper- and bottom-light intensities, it resulted in a gel-immobilized colloidal crystal film with a broadened Bragg reflection peak. Moreover, the width of the Bragg peak increased from 30 to 190 nm as the difference between the light intensities increased. Films with wider Bragg peaks exhibited a brighter reflection color because of the superposition of the shifted Bragg reflections. Furthermore, the Bragg wavelength could be varied over a wide range (500–650 nm) while maintaining the same broadened effective bandwidth by varying the swelling solvent concentration. These findings will expand the applicability of colloidal crystals for use in photonic devices and color pigments. Full article
(This article belongs to the Special Issue Preparation, Properties and Applications of Functional Hydrogels)
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26 pages, 846 KiB  
Review
State of the Art of Hydrogel Wound Dressings Developed by Ionizing Radiation
by Maria Demeter, Anca Scărișoreanu and Ion Călina
Gels 2023, 9(1), 55; https://doi.org/10.3390/gels9010055 - 10 Jan 2023
Cited by 14 | Viewed by 3141
Abstract
The development of an ideal hydrogel wound dressing with excellent characteristics is currently a significant demand in wound therapy. The ideal hydrogel wound dressing must provide a moist environment between the wound and the dressing, promote wound healing, absorb excess exudate and toxins, [...] Read more.
The development of an ideal hydrogel wound dressing with excellent characteristics is currently a significant demand in wound therapy. The ideal hydrogel wound dressing must provide a moist environment between the wound and the dressing, promote wound healing, absorb excess exudate and toxins, be completely sterile, and not adhere to the wound. The evolution and current status of research on hydrogel wound dressings obtained exclusively through production by ionizing radiation are discussed in this paper review, along with the preparation methods, properties, standard characterization techniques, and their applications in wound dressing. First, we described the methods for synthesizing hydrogel wound dressings with ionizing radiation. Then, standard methods of characterization of hydrogel wound dressings such as gel fraction, swelling degree, sol–gel analysis, rheological properties, morphology, moisture retention capability, and water vapor transmission rate have been investigated. In the end, specific attention was paid to the drug release, antibacterial performance, and cytotoxicity of hydrogels. Moreover, the application of hydrogel in regenerative medicine as wound healing dressing was covered. Full article
(This article belongs to the Special Issue Properties and Applications of Biomaterials Related to Gels)
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7 pages, 1365 KiB  
Article
Thermosensitive Shape-Memory Poly(stearyl acrylate-co-methoxy poly(ethylene glycol) acrylate) Hydrogels
by Hideaki Tokuyama, Ryo Iriki and Makino Kubota
Gels 2023, 9(1), 54; https://doi.org/10.3390/gels9010054 - 10 Jan 2023
Cited by 2 | Viewed by 1788
Abstract
Stimuli-sensitive hydrogels are highly desirable candidates for application in intelligent biomaterials. Thus, a novel thermosensitive hydrogel with shape-memory function was developed. Hydrophobic stearyl acrylate (SA), hydrophilic methoxy poly(ethylene glycol) acrylate (MPGA), and a crosslinking monomer were copolymerized to prepare poly(SA-co-MPGA) gels [...] Read more.
Stimuli-sensitive hydrogels are highly desirable candidates for application in intelligent biomaterials. Thus, a novel thermosensitive hydrogel with shape-memory function was developed. Hydrophobic stearyl acrylate (SA), hydrophilic methoxy poly(ethylene glycol) acrylate (MPGA), and a crosslinking monomer were copolymerized to prepare poly(SA-co-MPGA) gels with various mole fractions of SA (xSA) in ethanol. Subsequently, the prepared gels were washed, dried, and re-swelled in water at 50 °C. Differential scanning calorimetric (DSC) and compression tests at different temperatures revealed that poly(SA-co-MPGA) hydrogels with xSA > 0.5 induce a crystalline-to-amorphous transition, which is a hard-to-soft transition at ~40 °C that is based on the formation/non-formation of a crystalline structure containing stearyl side chains. The hydrogels stored in water maintained an almost constant volume, independent of the temperature. The poly(SA-co-MPGA) hydrogel was soft, flexible, and deformed at 50 °C. However, the hydrogel stiffened when cooled to room temperature, and the deformation was reversible. The shape-memory function of poly(SA-co-MPGA) hydrogels is proposed for potential use in biomaterials; this is partially attributed to the use of MPGA, which consists of relatively biocompatible poly(ethylene glycol). Full article
(This article belongs to the Special Issue Advances in Smart and Tough Hydrogels)
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23 pages, 7829 KiB  
Article
Curative Effects of Copper Iodide Embedded on Gallic Acid Incorporated in a Poly(vinyl alcohol) (PVA) Liquid Bandage
by Putita Phetcharat, Pakakrong Sangsanoh, Chasuda Choipang, Sonthaya Chaiarwut, Orawan Suwantong, Piyachat Chuysinuan and Pitt Supaphol
Gels 2023, 9(1), 53; https://doi.org/10.3390/gels9010053 - 8 Jan 2023
Cited by 4 | Viewed by 2059
Abstract
In daily life, people are often receiving minor cuts due to carelessness, leaving wounds on the skin. If wound healing is interrupted and the healing process does not finish, pathogens can easily enter wounds and cause infection. Liquid bandages are a fast and [...] Read more.
In daily life, people are often receiving minor cuts due to carelessness, leaving wounds on the skin. If wound healing is interrupted and the healing process does not finish, pathogens can easily enter wounds and cause infection. Liquid bandages are a fast and convenient way to help stop the bleeding of superficial wounds. Moreover, antibacterial agents in liquid bandages can promote wound restoration and fight bacteria. Herein, a poly(vinyl alcohol) (PVA) liquid bandage incorporating copper iodide nanoparticles (CuI NPs) was developed. CuI NPs were synthesized through green synthesis using gallic acid (GA) as a reducing and capping agent. The sizes of the CuI NPs, which were dependent on the concentration of GA, were 41.45, 43.51 and 49.71 nm, with the concentrations of gallic acid being 0, 2.5 mM and 5.0 mM, respectively. CuI NPs were analyzed using FTIR, XRD and SEM and tested for peroxidase-like properties and antibacterial activity. Then, PVA liquid bandages were formulated with different concentrations of stock CuI suspension. The results revealed that PVA liquid bandages incorporating 0.190% CuI synthesized with 5.0 mM of GA can kill bacteria within 24 h and have no harmful effects on human fibroblast cells. Full article
(This article belongs to the Special Issue Bioceramics, Bioglasses and Gels for Tissue Engineering)
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18 pages, 3691 KiB  
Article
Electron Beam Irradiation Cross-Linked Hydrogel Patches Loaded with Red Onion Peel Extract for Transdermal Drug Delivery: Formulation, Characterization, Cytocompatibility, and Skin Permeation
by Pimpon Uttayarat, Rattanakorn Chiangnoon, Thanu Thongnopkoon, Kesinee Noiruksa, Jirachaya Trakanrungsie, Wattanaporn Phattanaphakdee, Chuda Chittasupho and Sirivan Athikomkulchai
Gels 2023, 9(1), 52; https://doi.org/10.3390/gels9010052 - 7 Jan 2023
Cited by 3 | Viewed by 2866
Abstract
The use of bioactive molecules derived from medicinal plants in wound healing has recently attracted considerable attention in both research and public interest. In this work, we demonstrated the first attempt to incorporate the extract from Thai red onion skins in hydrogel patches [...] Read more.
The use of bioactive molecules derived from medicinal plants in wound healing has recently attracted considerable attention in both research and public interest. In this work, we demonstrated the first attempt to incorporate the extract from Thai red onion skins in hydrogel patches intended for transdermal delivery. The red onion skin extract (ROSE) was first prepared and evaluated for cytotoxicity by MTT assay with both L929 and human dermal fibroblast cells. Hydrogel patches with porous microstructure and high water content were fabricated from polyvinyl alcohol (PVA) by electron beam irradiation and characterized for their physical, mechanical, morphological, and cytocompatible properties prior to the loading of ROSE. After decontamination by electron beam irradiation, the in vitro release profile exhibited the burst release of extract from ROSE-coated hydrogel patches within 5 h, followed by the sustained release up to 48 h. Finally, evaluation of skin permeation using Franz cell setup with a newborn pig skin model showed that the permeation of ROSE from the hydrogel patch increased with time and reached the maximum of 262 µg/cm2, which was well below the cytotoxicity threshold, at 24 h. These results demonstrated that our ROSE-coated hydrogel patches could potentially be used in transdermal delivery. Full article
(This article belongs to the Special Issue Biofunctional Gels)
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15 pages, 7618 KiB  
Article
Assessing Polysaccharides/Aloe Vera–Based Hydrogels for Tumor Spheroid Formation
by Petruța Preda, Ana-Maria Enciu, Cristiana Tanase, Maria Dudau, Lucian Albulescu, Monica-Elisabeta Maxim, Raluca Nicoleta Darie-Niță, Oana Brincoveanu and Marioara Avram
Gels 2023, 9(1), 51; https://doi.org/10.3390/gels9010051 - 7 Jan 2023
Cited by 2 | Viewed by 2294
Abstract
In vitro tumor spheroids have proven to be useful 3D tumor culture models for drug testing, and determining the molecular mechanism of tumor progression and cellular interactions. Therefore, there is a continuous search for their industrial scalability and routine preparation. Considering that hydrogels [...] Read more.
In vitro tumor spheroids have proven to be useful 3D tumor culture models for drug testing, and determining the molecular mechanism of tumor progression and cellular interactions. Therefore, there is a continuous search for their industrial scalability and routine preparation. Considering that hydrogels are promising systems that can favor the formation of tumor spheroids, our study aimed to investigate and develop less expensive and easy-to-use amorphous and crosslinked hydrogels, based on natural compounds such as sodium alginate (NaAlg), aloe vera (AV) gel powder, and chitosan (CS) for tumor spheroid formation. The ability of the developed hydrogels to be a potential spheroid-forming system was evaluated using MDA-MB-231 and U87MG cancer cells. Spheroid abilities were influenced by pH, viscosity, and crosslinking of the hydrogel. Addition of either AV or chitosan to sodium alginate increased the viscosity at pH 5, resulting in amorphous hydrogels with a strong gel texture, as shown by rheologic analysis. Only the chitosan-based gel allowed formation of spheroids at pH 5. Among the variants of AV-based amorphous hydrogels tested, only hydrogels at pH 12 and with low viscosity promoted the formation of spheroids. The crosslinked NaAlg/AV, NaAlg/AV/glucose, and NaAlg/CS hydrogel variants favored more efficient spheroid formation. Additional studies would be needed to use AV in other physical forms and other formulations of hydrogels, as the current study is an initiation, in evaluating the potential use of AV gel in tumor spheroid formation systems. Full article
(This article belongs to the Special Issue Polymer Hydrogels for Cancer Therapy)
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18 pages, 3304 KiB  
Article
Emulsion Gels Formed by Electrostatic Interaction of Gelatine and Modified Corn Starch via pH Adjustments: Potential Fat Replacers in Meat Products
by Abu Bakar Asyrul-Izhar, Jamilah Bakar, Awis Qurni Sazili, Yong Meng Goh and Mohammad Rashedi Ismail-Fitry
Gels 2023, 9(1), 50; https://doi.org/10.3390/gels9010050 - 7 Jan 2023
Cited by 5 | Viewed by 2425
Abstract
The application of emulsion gels as animal fat replacers in meat products has been focused on due to their unique physicochemical properties. The electrostatic interaction between proteins and polysaccharides could influence emulsion gel stability. This study aimed to evaluate the physicochemical properties of [...] Read more.
The application of emulsion gels as animal fat replacers in meat products has been focused on due to their unique physicochemical properties. The electrostatic interaction between proteins and polysaccharides could influence emulsion gel stability. This study aimed to evaluate the physicochemical properties of emulsion gels using starch and gelatin as stabilizers, promoting electrostatic attraction via pH adjustment. Three systems were studied: emulsion gel A (EGA) and emulsion gel B (EGB), which have positive and negative net charges that promote electrostatic interaction, and emulsion gel C (EGC), whose charge equals the isoelectric point and does not promote electrostatic interactions. There was no significant difference in proximate analysis, syneresis and thermal stability between samples, while EGA and EGB had higher pH values than EGC. The lightness (L*) value was higher in EGA and EGB, while the yellowness (b*) value was the highest in EGC. The smaller particle size (p < 0.05) in EGA and EGB also resulted in higher gel strength, hardness and oxidative stability. Microscopic images showed that EGA and EGB had a more uniform matrix structure. X-ray diffraction demonstrated that all the emulsion gels crystallized in a β′ polymorph form. Differential scanning calorimetry (DSC) revealed a single characteristic peak was detected in both the melting and cooling curves for all the emulsion gels, which indicated that the fat exists in a single polymorphic state. All emulsion gels presented a high amount of unsaturated fatty acids and reduced saturated fat by up to 11%. Therefore, the emulsion gels (EGA and EGB) that favored the electrostatic protein-polysaccharide interactions are suitable to be used as fat replacers in meat products. Full article
(This article belongs to the Section Gel Applications)
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18 pages, 20672 KiB  
Article
Development of Composite Edible Coating from Gelatin-Pectin Incorporated Garlic Essential Oil on Physicochemical Characteristics of Red Chili (Capsicum annnum L.)
by Windy Heristika, Andriati Ningrum, Supriyadi, Heli Siti Helimatul Munawaroh and Pau Loke Show
Gels 2023, 9(1), 49; https://doi.org/10.3390/gels9010049 - 6 Jan 2023
Cited by 3 | Viewed by 2568
Abstract
Red chili is a climacteric fruit that still undergoes respiration after harvest. During storage, it is susceptible to mechanical, physical, and physiological damage and decay incidence, therefore a method is needed to protect it so that the quality losses can be minimized. One [...] Read more.
Red chili is a climacteric fruit that still undergoes respiration after harvest. During storage, it is susceptible to mechanical, physical, and physiological damage and decay incidence, therefore a method is needed to protect it so that the quality losses can be minimized. One way this can be achieved is by applying edible coatings that can be made from hydrocolloids, lipids, or composites of both, in addition to antimicrobial agents that can also be added to inhibit microbial growth. In this study, we detail the application of an edible coating made of gelatin composite from tilapia fish skin, which has a transparent color and good barrier properties against O2, CO2, and lipids. To increase its physicochemical and functional qualities, it must be modified by adding composite elements such as pectin as well as hydrophobic ingredients such as garlic essential oil. This study was conducted to determine the effect of a gelatin–pectin composite edible coating (75:25, 50:50, 25:75), which was incorporated with garlic essential oil (2% and 3%) on the physicochemical properties of red chili at room temperature (±29 °C), RH ± 69%) for 14 days. The best treatment was the 50–50% pectin–gelatin composite, which was incorporated with garlic essential oil with a concentration of 2 and 3%. This treatment provided a protective effect against changes in several physicochemical properties: inhibiting weight loss of 36.36 and 37.03%, softening of texture by 0.547 and 0.539 kg/84 mm2, maintaining acidity of 0.0087 and 0.0081%, maintaining vitamin C content of 2.237 and 2.349 mg/gr, anti-oxidant activity (IC50) 546.587 and 524.907; it also provided a protective effect on chili colors changing to red, and retains better total dissolved solid values. Full article
(This article belongs to the Special Issue Recent Developments in Food Gels)
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21 pages, 3115 KiB  
Article
Potential Hemostatic and Wound Healing Effects of Thermoresponsive Wound Dressing Gel Loaded with Lignosus rhinocerotis and Punica granatum Extracts
by Farha Yasmin Faris Taufeq, Nur Hamizah Habideen, Loageshwari Nagaswa Rao, Promit Kumar Podder and Haliza Katas
Gels 2023, 9(1), 48; https://doi.org/10.3390/gels9010048 - 6 Jan 2023
Cited by 3 | Viewed by 2104
Abstract
Biologically active compounds in Lignosus rhinocerotis and Punica granatum are found to facilitate wound healing and exhibit hemostatic activity, making them a good combination as bioactives for wound dressings. This study, therefore, aimed to evaluate the potential of thermoresponsive gels loaded with L. [...] Read more.
Biologically active compounds in Lignosus rhinocerotis and Punica granatum are found to facilitate wound healing and exhibit hemostatic activity, making them a good combination as bioactives for wound dressings. This study, therefore, aimed to evaluate the potential of thermoresponsive gels loaded with L. rhinocerotis (HLRE) and P. granatum (PPE) extracts as dressings for wound treatment. The gels were prepared using Pluronic PF127 polymer and mixed with PEG 400 and/or starch prior to incorporation with both extracts (0.06 to 1 mg/mL). The gelation temperature (Tgel) at the skin temperature was achieved when Pluronic PF127 was mixed with 22% w/v PEG 400 and reduced to 25.7 ± 0.3–26.7 ± 1.2 °C after adding HLRE and PPE. The gels exhibited satisfactory hardness (2.02 ± 0.19–6.45 ± 0.53 N), cohesiveness (0.9 ± 0.07–2.28 ± 0.4 mJ), adhesiveness (5.07 ± 2.41–19.6 ± 1.1 mJ), and viscosity (0.15 ± 0.04–0.95 ± 0.03 Pa.s), suitable for wound dressings. The optimized gels displayed high thrombin activity and cell migration rate (wound closure of 74% ± 12–89% ± 2 within 24 h), demonstrating hemostatic and healing effects. The thermoresponsive gels demonstrated advantages to be used as dressings for treating acute and open wounds. Full article
(This article belongs to the Special Issue Drug-Loaded Hydrogel Biomaterials)
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20 pages, 3983 KiB  
Article
The Influence of Emulsifiers on the Physiochemical Behavior of Soy Wax/Rice Bran Oil-Based Oleogels and Their Application in Nutraceutical Delivery
by Somali Dhal, Abdullah Alhamidi, Saeed M. Al-Zahrani, Arfat Anis and Kunal Pal
Gels 2023, 9(1), 47; https://doi.org/10.3390/gels9010047 - 6 Jan 2023
Cited by 6 | Viewed by 2137
Abstract
This research evaluated the influence of stearic acid, sunflower lecithin, and sorbitan monooleate on soy wax (SYW)/rice bran oil (RBO)-based oleogels. The physiochemical behavior of oleogel samples was evaluated using colorimetry, microscopy, FTIR, mechanical, crystallization kinetics, X-ray diffraction, and a drug release investigation. [...] Read more.
This research evaluated the influence of stearic acid, sunflower lecithin, and sorbitan monooleate on soy wax (SYW)/rice bran oil (RBO)-based oleogels. The physiochemical behavior of oleogel samples was evaluated using colorimetry, microscopy, FTIR, mechanical, crystallization kinetics, X-ray diffraction, and a drug release investigation. The prepared oleogels were light yellow, and adding emulsifiers did not change their appearance. All oleogels showed an oil binding capacity of >98%, independent of emulsifier treatment. The surface topography revealed that emulsifiers smoothed the surface of the oleogels. Bright-field and polarized micrographs showed the presence of wax grains and needles. FTIR spectra indicated that oleogel samples had the same functional group diversity as the raw materials. The oleogel samples lacked a hydrogen-bonding peak. Hence, we postulated that non-covalent interactions were involved in the oleogel preparation. According to stress relaxation studies, the firmness and elastic component of oleogels were unaffected by emulsifiers. However, EML3 (oleogel containing sorbitan monooleate) showed lower relaxing characteristics than the others. EML3 exhibited the slowest crystallization profile. Due to its low d-spacing, EML3 was found to have densely packed crystal molecules and the largest crystallite size. The in vitro drug release studies showed that emulsifier-containing oleogels dramatically affected curcumin release. These results may help customize oleogels properties to adjust bioactive component release in the food and pharmaceutical industries. Full article
(This article belongs to the Section Gel Applications)
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2 pages, 196 KiB  
Editorial
Editorial on the Special Issue “Advances in Composite Gels”
by Hiroyuki Takeno
Gels 2023, 9(1), 46; https://doi.org/10.3390/gels9010046 - 6 Jan 2023
Cited by 2 | Viewed by 1248
Abstract
Polymer gels are soft materials composed of a large amount of solvent (water, organic solvent, and ionic liquid) and a polymer, and they are constructed using a three-dimensional network [...] Full article
(This article belongs to the Special Issue Advance in Composite Gels)
18 pages, 7273 KiB  
Article
Enrichment of 3D-Printed k-Carrageenan Food Gel with Callus Tissue of Narrow-Leaved Lupin Lupinus angustifolius
by Kseniya Belova, Elena Dushina, Sergey Popov, Andrey Zlobin, Ekaterina Martinson, Fedor Vityazev and Sergey Litvinets
Gels 2023, 9(1), 45; https://doi.org/10.3390/gels9010045 - 6 Jan 2023
Cited by 4 | Viewed by 2947
Abstract
The aim of the study is to develop and evaluate the printability of k-carrageenan inks enriched with callus tissue of lupin (L. angustifolius) and to determine the effect of two lupin calluses (LA14 and LA16) on the texture and digestibility of [...] Read more.
The aim of the study is to develop and evaluate the printability of k-carrageenan inks enriched with callus tissue of lupin (L. angustifolius) and to determine the effect of two lupin calluses (LA14 and LA16) on the texture and digestibility of 3D-printed gel. The results demonstrated that the enriched ink was successfully 3D printed at concentrations of 33 and 50 g/100 mL of LA14 callus and 33 g/100 mL of LA16 callus. The feasibility of 3D printing is extremely reduced at higher concentrations of callus material in the ink. The hardness, cohesiveness, and gumminess of the 3D-printed gel with LA16 callus were weakened compared to the gel with LA14 callus. The results of rheological measurements showed that an increase in the content of LA16 callus interfered with the formation of a k-carrageenan gel network, while LA14 callus strengthened the k-carrageenan gel with increasing concentration. Gel samples at different concentrations of LA14 and LA16 calluses formed a spongy network structure, but the number of pores decreased, and their size increased, when the volume fraction occupied by LA14 and LA16 calluses increased. Simple polysaccharides, galacturonic acid residues, and phenolic compounds (PCs) were released from A-FP gels after sequential in vivo oral and in vitro gastrointestinal digestion. PCs were released predominantly in the simulated intestinal and colonic fluids. Thus, incorporating lupin callus into the hydrocolloid ink for food 3D printing can be a promising approach to developing a gelling material with new mechanical, rheological, and functional properties. Full article
(This article belongs to the Special Issue Recent Developments in Food Gels)
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14 pages, 3561 KiB  
Article
Preparation of MOF-Based Core-Shell Gel Particles with Catalytic Activity and Their Plugging Performance
by Fengbao Liu, Jinsheng Sun and Xiao Luo
Gels 2023, 9(1), 44; https://doi.org/10.3390/gels9010044 - 4 Jan 2023
Cited by 1 | Viewed by 1633
Abstract
Drilling fluid systems for deep and ultra-deep wells are hampered by both high-temperature downhole environments and lengthy cycle periods. Suppose that the gel particle-plugging agent, the primary treatment agent in the system, fails to offer durable and stable plugging performance. In such a [...] Read more.
Drilling fluid systems for deep and ultra-deep wells are hampered by both high-temperature downhole environments and lengthy cycle periods. Suppose that the gel particle-plugging agent, the primary treatment agent in the system, fails to offer durable and stable plugging performance. In such a scenario, the borehole wall is susceptible to instability and landslide after prolonged immersion, leading to downhole accidents. In this study, novel core-shell gel particles (modified ZIF) with ZIF particles employed as the core material and organosilicon-modified polyethylene polyamine (PEPA) as the polymer shell were fabricated using PEPA, in-house synthesized (3-aminopropyl) triethoxysilane (APTS), and the ZIF-8 metal-organic framework (MOF) as the raw materials to enhance the long-term plugging performance of gel plugging agents. The modified ZIF particles are nanoscale polygonal crystals and differ from conventional core-shell gel particles in that they feature high molecular sieve catalytic activity due to the presence of numerous interior micropores and mesopores. As a result, modified ZIF exhibits the performance characteristics of both rigid and flexible plugging agents and has an excellent catalytic cross-linking effect on the sulfonated phenolic resin (SMP-3) and sulfonated lignite resin (SPNH) in drilling fluids. Consequently, a cross-linking reaction occurs when SMP-3 and SPNH flow through the spacings in the plugging layer formed by the modified ZIF particles. This increases the viscosity of the liquid phase and simultaneously generates an insoluble gel, forming a particle-gel composite plugging structure with the modified ZIF and significantly enhancing the long-term plugging performance of the drilling fluid. Full article
(This article belongs to the Special Issue Gels for Oil Drilling and Enhanced Recovery)
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18 pages, 2657 KiB  
Article
Clarithromycin and Pantoprazole Gastro-Retentive Floating Bilayer Tablet for the Treatment of Helicobacter Pylori: Formulation and Characterization
by Ghufran Ullah, Asif Nawaz, Muhammad Shahid Latif, Kifayat Ullah Shah, Saeed Ahmad, Fatima Javed, Mulham Alfatama, Siti Aisyah Abd Ghafar and Vuanghao Lim
Gels 2023, 9(1), 43; https://doi.org/10.3390/gels9010043 - 4 Jan 2023
Cited by 3 | Viewed by 3109
Abstract
Bilayer/multilayer tablets have been introduced to formulate incompatible components for compound preparations, but they are now more commonly used to tailor drug release. This research aimed to formulate a novel gastro-retentive tablet to deliver a combination of a fixed dose of two drugs [...] Read more.
Bilayer/multilayer tablets have been introduced to formulate incompatible components for compound preparations, but they are now more commonly used to tailor drug release. This research aimed to formulate a novel gastro-retentive tablet to deliver a combination of a fixed dose of two drugs to eliminate Helicobacter pylori (H. pylori) in the gastrointestinal tract. The bilayer tablets were prepared by means of the direct compression technique. The controlled-release bilayer tablets were prepared using various hydrophilic swellable polymers (sodium alginate, chitosan, and HPMC-K15M) alone and in combination to investigate the percent of swelling behavior and average drug release. The weight of the controlled-release floating layer was 500 mg, whereas the weight of the floating tablets of pantoprazole was 100 mg. To develop the most-effective formulation, the effects of the experimental components on the floating lag time, the total floating time, T 50%, and the amount of drug release were investigated. The drugs’ and excipients’ compatibilities were evaluated using ATR-FTIR and DSC. Pre-compression and post-compression testing were carried out for the prepared tablets, and they were subjected to in vitro characterization studies. The pantoprazole layer of the prepared tablet demonstrated drug release (95%) in 2 h, whereas clarithromycin demonstrated sustained drug release (83%) for up to 24 h (F7). The present study concluded that the combination of sodium alginate, chitosan, and HPMC polymers (1:1:1) resulted in a gastro-retentive and controlled-release drug delivery system of the drug combination. Thus, the formulation of the floating bilayer tablets successfully resulted in a biphasic drug release. Moreover, the formulation (F7) offered the combination of two drugs in a single-tablet formulation containing various polymers (sodium alginate, chitosan, and HPMC polymers) as the best treatment option for local infections such as gastric ulcers. Full article
(This article belongs to the Special Issue Engineering Hydrogel for Biomedical Applications)
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12 pages, 10332 KiB  
Article
Calcium-Polyphosphate Submicroparticles (CaPP) Improvement Effect of the Experimental Bleaching Gels’ Chemical and Cellular-Viability Properties
by Mariángela Ivette Guanipa Ortiz, Juliana Jarussi dos Santos, Jonny Burga Sánchez, Ubirajara Pereira Rodrigues-Filho, Flávio Henrique Baggio Aguiar, Klaus Rischka and Débora Alves Nunes Leite Lima
Gels 2023, 9(1), 42; https://doi.org/10.3390/gels9010042 - 4 Jan 2023
Cited by 3 | Viewed by 1731
Abstract
The aim of this research was to develop and characterize the chemical and cellular-viability properties of an experimental high-concentration bleaching gel (35 wt%-H2O2) containing calcium-polyphosphate particles (CaPP) at two concentrations (0.5 wt% and 1.5 wt%). The CaPP submicroparticles were [...] Read more.
The aim of this research was to develop and characterize the chemical and cellular-viability properties of an experimental high-concentration bleaching gel (35 wt%-H2O2) containing calcium-polyphosphate particles (CaPP) at two concentrations (0.5 wt% and 1.5 wt%). The CaPP submicroparticles were synthesized by coprecipitation, keeping a Ca:P ratio of 2:1. The CaPP morphology, size, and chemical and crystal profiles were characterized through scanning and transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction, respectively. The assessed bleaching gels were experimental (without CaPP); 0.5% CaPP; 1.5% CaPP; and commercial. The gels’ pH values and H2O2 concentrations (iodometric titration) were determined. The odontoblast-like cell viability after a gel’s exposure was assessed by the MTT assay. The pH and H2O2 concentration were compared through a repeated-measures analysis of variance (ANOVA) and a Tukey’s test and the cell viability through a one-way ANOVA and a Tukey’s test using a GraphPad Prism (α < 0.05). The CaPP particles were spherical (with Ca and P, 135.7 ± 80.95 nm size) and amorphous. The H2O2 concentration decreased in all groups after mixing (p < 0.001). The 0.5% CaPP resulted in more-stable pH levels and higher viability levels than the experimental one (p < 0.05). The successful incorporation of CaPP had a positive impact on the bleaching gel’s chemical and cellular-viability properties when compared to the experimental gel without these particles. Full article
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