Gels | October 2022 - Browse Articles

15 pages, 4922 KiB

Open AccessArticle

Fabrication of Textile Waste Fibers Aerogels with Excellent Oil/Organic Solvent Adsorption and Thermal Properties

by Chunlei Dong, Yangzhao Hu, Yuxuan Zhu, Jiale Wang, Xuerui Jia, Jianbing Chen and Jingliang Li

Gels 2022, 8(10), 684; https://doi.org/10.3390/gels8100684 - 21 Oct 2022

Cited by 7 | Viewed by 3349

Abstract

In recent years, the treatment of textile waste has attracted more and more attention around the world. The reuse of textile waste can contribute to the reduction of carbon emissions and the sustainable development of the economy. Herein, we proposed a facile and [...] Read more.

In recent years, the treatment of textile waste has attracted more and more attention around the world. The reuse of textile waste can contribute to the reduction of carbon emissions and the sustainable development of the economy. Herein, we proposed a facile and cost-effective approach to fabricating aerogel by using textile waste fibers as the matrix and polyvinyl alcohol (PVA) and glutaraldehyde (GA) as crosslinking agents. After being modified with methyltrimethoxysilane (MTMS) via chemical vapor deposition, both the interior and exterior of the textile waste aerogels exhibit a hydrophobic property with a water contact angle of up to 136.9° ± 2.3°. A comprehensive investigation of the structure, thermal properties, mechanical properties and oil absorption capacity of this aerogel shows its potential for building insulation and oil spill cleanup. The textile waste fibers aerogels have low density and high porosity, good thermal stability and outstanding heat insulation properties (K_avg. = 0.049–0.061 W/m·K). With a maximum oil absorption value of 26.9 ± 0.6 g/g and rapid and effective oil/water mixture separation, the aerogel exhibits competitive commercial application value. Full article

(This article belongs to the Special Issue Dynamics of Gels and Its Applications)

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14 pages, 2995 KiB

Open AccessArticle

Thermo-/pH-Dual-Sensitive PEG/PAMAM Nanogel: Reaction Dynamics and Plugging Application of CO₂ Channeling

by Xiangbin Liu, Suling Wang, Weiguang Shi and He Liu

Gels 2022, 8(10), 683; https://doi.org/10.3390/gels8100683 - 21 Oct 2022

Cited by 6 | Viewed by 1634

Abstract

Smart hydrogels, owing to their exceptional viscoelastic and deformable capacity in response to environmental stimulation involving temperature and pH, have been successfully applied in oilfields for purposes such as water and/or gas shutoff treatments. However, the CO₂ breakthrough problem in low permeability [...] Read more.

Smart hydrogels, owing to their exceptional viscoelastic and deformable capacity in response to environmental stimulation involving temperature and pH, have been successfully applied in oilfields for purposes such as water and/or gas shutoff treatments. However, the CO₂ breakthrough problem in low permeability reservoirs has not been well solved. In this work, a rheological method-based Avrami dynamics model and Dickinson dynamics model were employed to investigate the dynamic gelation process of thermo-/pH-dual-sensitive PEG/PAMAM nanogels to further our understanding of the microstructure of their gelation and pertinence plugging application. Plugging experiments were performed by alternating injections of CO₂ and hydrogel solution in a slug type on three fractured low permeability cores with a backpressure of 13 MPa. The nanogels presented a secondary growth pattern from three to one dimension from micrometer to nanometer size with a morphological transformation from a sphere to an irregular ellipsoid or disk shape. The phase transition temperature was 50 °C, and the phase transition pH was 10. If both or either were below these values, the hydrogel swelled; otherwise, it shrank. Plugging results show that the plugging efficiency was higher than 99%. The maximum breakthrough pressure was 19.93 MPa, and the corresponding residual pressure remained 17.64 MPa for a 10 mD core, exhibiting great plugging performance and high residual resistance after being broken through by CO₂. Full article

(This article belongs to the Section Gel Applications)

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10 pages, 1881 KiB

Open AccessArticle

The Effect of Crosslinking Degree of Hydrogels on Hydrogel Adhesion

by Zhangkang Li, Cheng Yu, Hitendra Kumar, Xiao He, Qingye Lu, Huiyu Bai, Keekyoung Kim and Jinguang Hu

Gels 2022, 8(10), 682; https://doi.org/10.3390/gels8100682 - 21 Oct 2022

Cited by 39 | Viewed by 5731

Abstract

The development of adhesive hydrogel materials has brought numerous advances to biomedical engineering. Hydrogel adhesion has drawn much attention in research and applications. In this paper, the study of hydrogel adhesion is no longer limited to the surface of hydrogels. Here, the effect [...] Read more.

The development of adhesive hydrogel materials has brought numerous advances to biomedical engineering. Hydrogel adhesion has drawn much attention in research and applications. In this paper, the study of hydrogel adhesion is no longer limited to the surface of hydrogels. Here, the effect of the internal crosslinking degree of hydrogels prepared by different methods on hydrogel adhesion was explored to find the generality. The results show that with the increase in crosslinking degree, the hydrogel adhesion decreased significantly due to the limitation of segment mobility. Moreover, two simple strategies to improve hydrogel adhesion generated by hydrogen bonding were proposed. One was to keep the functional groups used for hydrogel adhesion and the other was to enhance the flexibility of polymer chains that make up hydrogels. We hope this study can provide another approach for improving the hydrogel adhesion generated by hydrogen bonding. Full article

(This article belongs to the Special Issue Advances in Hydrogels)

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21 pages, 6279 KiB

Open AccessArticle

Bioinspired Remineralization of Artificial Caries Lesions Using PDMAEMA/Carbomer/Calcium Phosphates Hybrid Microgels

by Alexander Bonchev, Marin Simeonov, Pavletta Shestakova, Radosveta Vasileva, Rositsa Titorenkova, Anton Apostolov, Elena Dyulgerova and Elena Vassileva

Gels 2022, 8(10), 681; https://doi.org/10.3390/gels8100681 - 21 Oct 2022

Cited by 3 | Viewed by 2521

Abstract

Dental caries remains one of the most prevalent bacterium-caused chronic diseases affecting both adults and children worldwide. The development of new materials for enhancing its remineralization is one of the most promising approaches in the field of advanced dental materials as well as [...] Read more.

Dental caries remains one of the most prevalent bacterium-caused chronic diseases affecting both adults and children worldwide. The development of new materials for enhancing its remineralization is one of the most promising approaches in the field of advanced dental materials as well as one of the main challenges in non-invasive dentistry. The aim of the present study is to develop novel hybrid materials based on (PDMAEMA)/Carbomer 940 microgels with in situ deposited calcium phosphates (CaP) and to reveal their potential as a remineralization system for artificial caries lesions. To this purpose, novel PDMAEMA/Carbomer 940 microgels were obtained and their core–shell structure was revealed by transmission electron microscopy (TEM). They were successfully used as a matrix for in situ calcium phosphate deposition, thus giving rise to novel hybrid microgels. The calcium phosphate phases formed during the deposition process were studied by X-ray diffraction and infrared spectroscopy, however, due to their highly amorphous nature, the nuclear magnetic resonance (NMR) was the method that was able to provide reliable information about the formed inorganic phases. The novel hybrid microgels were used for remineralization of artificial caries lesions in order to prove their ability to initiate their remineralization. The remineralization process was followed by scanning electron microscopy (SEM), X-ray diffraction, infrared and Raman spectroscopies and all these methods confirmed the successful enamel rod remineralization upon the novel hybrid microgel application. Thus, the study confirmed that novel hybrid microgels, which could ensure a constant supply of calcium and phosphate ions, are a viable solution for early caries treatment. Full article

(This article belongs to the Special Issue Functional Hydrogels for Biomedical Applications)

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17 pages, 1550 KiB

Open AccessEditor’s ChoiceArticle

Magnetically Activated Piezoelectric 3D Platform Based on Poly(Vinylidene) Fluoride Microspheres for Osteogenic Differentiation of Mesenchymal Stem Cells

by Maria Guillot-Ferriols, María Inmaculada García-Briega, Laia Tolosa, Carlos M. Costa, Senentxu Lanceros-Méndez, José Luis Gómez Ribelles and Gloria Gallego Ferrer

Gels 2022, 8(10), 680; https://doi.org/10.3390/gels8100680 - 20 Oct 2022

Cited by 5 | Viewed by 2890

Abstract

Mesenchymal stem cells (MSCs) osteogenic commitment before injection enhances bone regeneration therapy results. Piezoelectric stimulation may be an effective cue to promote MSCs pre-differentiation, and poly(vinylidene) fluoride (PVDF) cell culture supports, when combined with CoFe₂O₄ (CFO), offer a wireless in [...] Read more.

Mesenchymal stem cells (MSCs) osteogenic commitment before injection enhances bone regeneration therapy results. Piezoelectric stimulation may be an effective cue to promote MSCs pre-differentiation, and poly(vinylidene) fluoride (PVDF) cell culture supports, when combined with CoFe₂O₄ (CFO), offer a wireless in vitro stimulation strategy. Under an external magnetic field, CFO shift and magnetostriction deform the polymer matrix varying the polymer surface charge due to the piezoelectric effect. To test the effect of piezoelectric stimulation on MSCs, our approach is based on a gelatin hydrogel with embedded MSCs and PVDF-CFO electroactive microspheres. Microspheres were produced by electrospray technique, favouring CFO incorporation, crystallisation in β-phase (85%) and a crystallinity degree of around 55%. The absence of cytotoxicity of the 3D construct was confirmed 24 h after cell encapsulation. Cells were viable, evenly distributed in the hydrogel matrix and surrounded by microspheres, allowing local stimulation. Hydrogels were stimulated using a magnetic bioreactor, and no significant changes were observed in MSCs proliferation in the short or long term. Nevertheless, piezoelectric stimulation upregulated RUNX2 expression after 7 days, indicating the activation of the osteogenic differentiation pathway. These results open the door for optimising a stimulation protocol allowing the application of the magnetically activated 3D electroactive cell culture support for MSCs pre-differentiation before transplantation. Full article

(This article belongs to the Special Issue Injectable Gels: Applications in Drug Delivery and Tissue Engineering)

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21 pages, 6399 KiB

Open AccessArticle

Mussel-Inspired Surface Functionalization of Porous Albumin Cryogels Supporting Synergistic Antibacterial/Antioxidant Activity and Bone-Like Apatite Formation

by Nabila Mehwish, Mengdie Xu, Muhammad Zaeem and Bae Hoon Lee

Gels 2022, 8(10), 679; https://doi.org/10.3390/gels8100679 - 20 Oct 2022

Cited by 9 | Viewed by 2306

Abstract

A crucial method for adding new functions to current biomaterials for biomedical applications has been surface functionalization via molecular design. Mussel-inspired polydopamine (PDA) has generated much attention as a facile method for the functionalization of biomaterials because of its substantial independence in deposition, [...] Read more.

A crucial method for adding new functions to current biomaterials for biomedical applications has been surface functionalization via molecular design. Mussel-inspired polydopamine (PDA) has generated much attention as a facile method for the functionalization of biomaterials because of its substantial independence in deposition, beneficial cell interactions, and significant responsiveness aimed at secondary functionalization. Because of their porous structure, the bovine serum albumin methacryloyl (BSAMA)-BM cryogels were functionalized with PDA (BM-PDA), which may reproduce the architecture and biological purpose of the natural extracellular environment. Excellent antioxidative and antibacterial qualities, improved mineralization, and better cell responsiveness were all demonstrated by BM-PDA. BM-PDA scaffolds maintained their linked and uniform pores after functionalization, which can make it easier for nutrients to be transported during bone repair. As a result, hydroxyapatite (HA)-coated BM* and BM-PDA* cryogels were created through successive mineralization with the goal of mineralized bone tissue repair. The heterogeneous nucleation and surface roughness contributed to rod-like apatite production in BM-PDA* cryogels whereas BM* cryogels were made up of plate-like HA morphologies. Analysis results showed that after five cycles, the mineral contents were around 57% and the HA units remained equally dispersed on the surface of BM-PDA* with a Ca/P ratio of 1.63. Other natural polymer-based cryogels can be coated using this general, rapid, and simple PDA coating technique and utilized as implants for bone tissue engineering. Future clinical uses of albumin cryogels for bone tissue engineering will advance as a result of additional in-vivo testing of such PDA-coated cryogels. Full article

(This article belongs to the Special Issue Engineering Advanced Hydrogels for Biomedical Applications)

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16 pages, 3591 KiB

Open AccessArticle

One-Step Process of Mixed Oleic Acid Esters and Its High Temperature Lubrication Properties in Bentonite Gelling Suspension

by Xincheng Bao, Cunfa Ma and Fengshan Zhou

Gels 2022, 8(10), 678; https://doi.org/10.3390/gels8100678 - 20 Oct 2022

Cited by 1 | Viewed by 2048

Abstract

In recent years, with the increase in requirements for horizontal wells, ultra-high depth wells, small wells and branching wells, it has become increasingly important to deal with the conflict between drilling safety and bottomhole friction. In order to meet the requirements of complex [...] Read more.

In recent years, with the increase in requirements for horizontal wells, ultra-high depth wells, small wells and branching wells, it has become increasingly important to deal with the conflict between drilling safety and bottomhole friction. In order to meet the requirements of complex boreholes and deepwater drilling processes, it is crucial to improve the performance of ester-based lubricants. Oleic acid esters are relatively stable and have high lubricity at low temperature, however, these can be hydrolyzed at high temperature. However, the structure of carboxylic acids and alcohols can significantly affect the performance of synthetic esters. In order to solve the problem of balancing the high-temperature performance and low temperature performance of oleic acid esters with different structures, we propose a new oleic acid esterification process. After mixing methanol and ethylene glycol, it is reacted with oleic acid, and the mixed oleate prepared is named MEO-21, and the optimal esterification conditions are obtained as follows: the reaction time is 3 h, the reaction temperature is 150 °C, and concentrated sulfuric acid is the catalyst. MEO-21 not only achieves an extreme pressure lubrication coefficient reduction rate (Δf) of 86.57% at room temperature, but maintains a stable performance after hot rolling at high temperatures. Hot rolling at 150 °C for 16 h, Δf was 85.25%, hot rolling at 180 °C for 16 h, Δf was 89.56%. MEO-21 was used as a base oil with other industrial by-product oils to compound and produce a high-temperature-resistant lubricant that was named L-541, L-541′s Δf was 90.39% at room temperature. L-541 was hot-rolling at 120 °C, 150 °C and 180 °C for 16 h, the Δf was stabled at 89%. Full article

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19 pages, 6368 KiB

Open AccessArticle

Novel Silica Hybrid Xerogels Prepared by Co-Condensation of TEOS and ClPhTEOS: A Chemical and Morphological Study

by Guillermo Cruz-Quesada, Maialen Espinal-Viguri, María Victoria López-Ramón and Julián J. Garrido

Gels 2022, 8(10), 677; https://doi.org/10.3390/gels8100677 - 20 Oct 2022

Cited by 9 | Viewed by 2900

Abstract

The search for new materials with improved properties for advanced applications is, nowadays, one of the most relevant and booming fields for scientists due to the environmental and technological needs of our society. Within this demand, hybrid siliceous materials, made out of organic [...] Read more.

The search for new materials with improved properties for advanced applications is, nowadays, one of the most relevant and booming fields for scientists due to the environmental and technological needs of our society. Within this demand, hybrid siliceous materials, made out of organic and inorganic species (ORMOSILs), have emerged as an alternative with endless chemical and textural possibilities by incorporating in their structure the properties of inorganic compounds (i.e., mechanical, thermal, and structural stability) in synergy with those of organic compounds (functionality and flexibility), and thus, bestowing the material with unique properties, which allow access to multiple applications. In this work, synthesis using the sol-gel method of a series of new hybrid materials prepared by the co-condensation of tetraethoxysilane (TEOS) and 4-chlorophenyltriethoxysilane (ClPhTEOS) in different molar ratios is described. The aim of the study is not only the preparation of new materials but also their characterization by means of different techniques (FT-IR, ²⁹Si NMR, X-ray Diffraction, and N₂/CO₂ adsorption, among others) to obtain information on their chemical behavior and porous structure. Understanding how the chemical and textural properties of these materials are modulated with respect to the molar percentage of organic precursor will help to envisage their possible applications: From the most conventional such as catalysis, adsorption, or separation, to the most advanced in nanotechnology such as microelectronics, photoluminescence, non-linear optics, or sensorics. Full article

(This article belongs to the Special Issue Advances in Silica Xero- and Aerogels: From Synthesis to Structure–Activity Relationship)

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13 pages, 2959 KiB

Open AccessArticle

Development and Characterization of Chitosan and Chondroitin Sulfate Based Hydrogels Enriched with Garlic Extract for Potential Wound Healing/Skin Regeneration Applications

by Fatima Masood, Muhammad Atif Makhdoom, Iftikhar Ahmed Channa, Sadaf Jamal Gilani, Ahmad Khan, Rabia Hussain, Syeda Ammara Batool, Kiran Konain, Saeed Ur Rahman, Abdul Wadood, May Nasser bin Jumah and Muhammad Atiq Ur Rehman

Gels 2022, 8(10), 676; https://doi.org/10.3390/gels8100676 - 20 Oct 2022

Cited by 8 | Viewed by 3103

Abstract

Hydrogels can provide instant relief to pain and facilitate the fast recovery of wounds. Currently, the incorporation of medicinal herbs/plants in polymer matrix is being investigated due to their anti-bacterial and wound healing properties. Herein, we investigated the novel combination of chitosan (CS) [...] Read more.

Hydrogels can provide instant relief to pain and facilitate the fast recovery of wounds. Currently, the incorporation of medicinal herbs/plants in polymer matrix is being investigated due to their anti-bacterial and wound healing properties. Herein, we investigated the novel combination of chitosan (CS) and chondroitin sulfate (CHI) to synthesize hydrogels through freeze gelation process and enriched it with garlic (Gar) by soaking the hydrogels in garlic juice for faster wound healing and resistance to microbial growth at the wound surface. The synthesized hydrogels were characterized via Fourier-transform infrared spectroscopy (FTIR), which confirmed the presence of relevant functional groups. The scanning electron microscopy (SEM) images exhibited the porous structure of the hydrogels, which is useful for the sustained release of Gar from the hydrogels. The synthesized hydrogels showed significant inhibition zones against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, cell culture studies confirmed the cyto-compatibility of the synthesized hydrogels. Thus, the novel hydrogels presented in this study can offer an antibacterial effect during wound healing and promote tissue regeneration. Full article

(This article belongs to the Special Issue Advanced Hydrogels for Regenerative Medicine and Tissue Engineering)

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19 pages, 6108 KiB

Open AccessArticle

Hydrophobic Modification of ZrO₂-SiO₂ Xerogel and Its Adsorption Properties to Rhodamine B

by Yan Liu and Jing Yang

Gels 2022, 8(10), 675; https://doi.org/10.3390/gels8100675 - 20 Oct 2022

Cited by 5 | Viewed by 1679 | Correction

Abstract

Zirconium nitrate pentahydrate (Zr(NO₃)₄·5H₂O) and tetraethyl orthosilicate (TEOS) are used as the zirconium source and silicon source, respectively, and methyltriethoxysilane (MTES) as the hydrophobic modifier; the hydrophilic and hydrophobic ZrO₂-SiO₂ xerogels were prepared successfully. [...] Read more.

Zirconium nitrate pentahydrate (Zr(NO₃)₄·5H₂O) and tetraethyl orthosilicate (TEOS) are used as the zirconium source and silicon source, respectively, and methyltriethoxysilane (MTES) as the hydrophobic modifier; the hydrophilic and hydrophobic ZrO₂-SiO₂ xerogels were prepared successfully. The xerogels were characterized using Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and N₂ adsorption–desorption measurement. The adsorption mechanism of hydrophobic ZrO₂-SiO₂ xerogels to RhB was described by the kinetic and adsorption isotherms. The results showed that the introduction of Si-CH₃ groups can make the average pore size, BET surface area, and total pore volume of ZrO₂-SiO₂ xerogel increase. The hydrophobic ZrO₂-SiO₂ xerogel displays an adsorption capacity of 169.23 mg·g⁻¹ for RhB dye at 25 °C and pH = 3. The adsorption process of hydrophobic ZrO₂-SiO₂ xerogel to RhB followed a pseudo–second-order kinetic model. Fitting results from the D–R model of adsorption indicate that the adsorption of RhB onto the hydrophobic ZrO₂-SiO₂ xerogels is mainly physical, accompanied by a spontaneous heat absorption process. The regeneration and recycling properties of hydrophobic xerogels were investigated, and their recoverability and reusability were demonstrated. Full article

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13 pages, 3327 KiB

Open AccessArticle

Secretion of Bacillus amyloliquefaciens Transglutaminase from Lactococcus lactis and Its Enhancement of Food Gel Properties

by Tiange Ma, Xingjiang Li, Manuel Montalbán-López, Xuefeng Wu, Zhi Zheng and Dongdong Mu

Gels 2022, 8(10), 674; https://doi.org/10.3390/gels8100674 - 20 Oct 2022

Cited by 2 | Viewed by 1681

Abstract

(1) Background: Microbial transglutaminases (MTGase) catalyze protein crosslink. This is useful in the food industry to improve gelation, water holding capacity, and emulsifying capacity during foodstuff manufacturing. The production of MTGase in wild-type strains renders low yield and high costs of downstream purification, [...] Read more.

(1) Background: Microbial transglutaminases (MTGase) catalyze protein crosslink. This is useful in the food industry to improve gelation, water holding capacity, and emulsifying capacity during foodstuff manufacturing. The production of MTGase in wild-type strains renders low yield and high costs of downstream purification, limiting its industrial applications. (2) Methods: In this work, MTGase from Bacillus amyloliquefaciens BH072 (BaMTGase) has been heterologously expressed in Lactococcus lactis, using the signal peptide Usp45 to direct the secretion of recombinant BaMTGase out of the cell for easier purification. (3) Results: In these conditions, MTGase was purified with a high yield (48.7 ± 0.2 mg/L) and high enzyme activity (28.6 ± 0.5 U/mg). Next, BaMTGase was tested for industrial applications. Recombinant BaMTGase and commercial MTGase were used for SPI solution crosslinking. BaMTGase formed a harder gel with higher water-holding capacity and a dense and smooth gel microstructure. (4) Conclusions: This work provides an attractive food-grade cell factory for the food industry and offers a suitable chassis for MTGase production. Full article

(This article belongs to the Special Issue Research Progress in Food Gels)

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20 pages, 7826 KiB

Open AccessArticle

Photocatalytic and Antibacterial Properties of Doped TiO₂ Nanopowders Synthesized by Sol−Gel Method

by Silviu Preda, Jeanina Pandele-Cușu, Simona Viorica Petrescu, Elena Mădălina Ciobanu, Gabriela Petcu, Daniela C. Culiță, Nicoleta G. Apostol, Ruxandra M. Costescu, Iuliana Raut, Mariana Constantin and Luminița Predoană

Gels 2022, 8(10), 673; https://doi.org/10.3390/gels8100673 - 20 Oct 2022

Cited by 14 | Viewed by 2261

Abstract

For environmental applications, nanosized TiO₂-based materials are known as the most important photocatalyst and are intensively studied for their advantages such as their higher activity, lower price, and chemical and photoresist properties. Zn or Cu doped TiO₂ nanoparticles with anatase [...] Read more.

For environmental applications, nanosized TiO₂-based materials are known as the most important photocatalyst and are intensively studied for their advantages such as their higher activity, lower price, and chemical and photoresist properties. Zn or Cu doped TiO₂ nanoparticles with anatase crystalline structure were synthesized by sol−gel process. Titanium (IV) butoxide was used as a TiO₂ precursor, with parental alcohol as a solvent, and a hydrolysing agent (ammonia-containing water) was added to obtain a solution with pH 10. The gels were characterized by TG/DTA analysis, SEM, and XPS. Based on TG/DTA results, the temperature of 500 °C was chosen for processing the powders in air. The structure of the samples thermally treated at 500 °C was analysed by XRD and the patterns show crystallization in a single phase of TiO₂ (anatase). The surface of the samples and the oxidation states was investigated by XPS, confirming the presence of Ti, O, Zn and Cu. The antibacterial activity of the nanoparticle powder samples was verified using the gram−positive bacterium Staphylococcus aureus. The photocatalytic efficiency of the doped TiO₂ nanopowders for degradation of methyl orange (MO) is here examined in order to evaluate the potential applications of these materials for environmental remediation. Full article

(This article belongs to the Special Issue Gels: Synthesis, Characterization and Applications in High Performance Chemistry)

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14 pages, 3053 KiB

Open AccessArticle

A Peptide-Based Hydrogel for Adsorption of Dyes and Pharmaceuticals in Water Remediation

by Anna Fortunato and Miriam Mba

Gels 2022, 8(10), 672; https://doi.org/10.3390/gels8100672 - 19 Oct 2022

Cited by 14 | Viewed by 2743

Abstract

The removal of dyes and pharmaceuticals from water has become a major issue in recent years due to the shortage of freshwater resources. The adsorption of these pollutants through nontoxic, easy-to-make, and environmentally friendly adsorbents has become a popular topic. In this work, [...] Read more.

The removal of dyes and pharmaceuticals from water has become a major issue in recent years due to the shortage of freshwater resources. The adsorption of these pollutants through nontoxic, easy-to-make, and environmentally friendly adsorbents has become a popular topic. In this work, a tetrapeptide–pyrene conjugate was rationally designed to form hydrogels under controlled acidic conditions. The hydrogels were thoroughly characterized, and their performance in the adsorption of various dyes and pharmaceuticals from water was investigated. The supramolecular hydrogel efficiently adsorbed methylene blue (MB) and diclofenac (DCF) from water. The effect of concentration in the adsorption efficiency was studied, and results indicated that while the adsorption of MB is governed by the availability of adsorption sites, in the case of DCF, concentration is the driving force of the process. In the case of MB, the nature of the dye–hydrogel interactions and the mechanism of the adsorption process were investigated through UV–Vis absorption spectroscopy. The studies proved how this dye is first adsorbed as a monomer, probably through electrostatic interactions; successively, at increasing concentrations as the electrostatic adsorption sites are depleted, dimerization on the hydrogel surface occurs. Full article

(This article belongs to the Special Issue Functionalized Gels for Environmental Applications)

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13 pages, 4333 KiB

Open AccessArticle

Hydrophobic Cellulose Acetate Aerogels for Thermal Insulation

by Sizhao Zhang, Zhouyuan Yang, Xing Huang, Jing Wang, Yunyun Xiao, Junpeng He, Jian Feng, Shixian Xiong and Zhengquan Li

Gels 2022, 8(10), 671; https://doi.org/10.3390/gels8100671 - 19 Oct 2022

Cited by 10 | Viewed by 3572

Abstract

As naturally derived material, cellulose aerogels have excellent thermal insulation properties due to their unique high porosity and three-dimensional mesoporous structure. However, its hydrophilic properties limit its application in the field of building insulation. Here, we propose a method to prepare high hydrophobicity [...] Read more.

As naturally derived material, cellulose aerogels have excellent thermal insulation properties due to their unique high porosity and three-dimensional mesoporous structure. However, its hydrophilic properties limit its application in the field of building insulation. Here, we propose a method to prepare high hydrophobicity by adopting the sol-gel method and chemical vapor reaction strategy using cellulose acetate type II as raw material and 2,4-toluene diisocyanate as the cross-linking agent. Thermal properties of cellulose acetate aerogels (CAAs) were measured, where pyridine was the catalyst, acetone was the solvent, and perfluorodecyltriethoxysilane (PFDS), hexamethyldisilazane (HMDS), and methyltriethoxysilane (MTES) were used as hydrophobic agents (by process hydrophobic test). Compared with MTES-modified cellulose acetate aerogels (M-CAAs) and HMDS (H-CAAs)-modified cellulose acetate aerogels, PFDS-modified (P-CAAs) cellulose acetate aerogels are the most hydrophobic. By implementing hydrophobic modification of PFDS both inside and outside the structure of cellulose acetate aerogels, the water contact angle can reach up to 136°, strongly demonstrating the potential of PFDS as a hydrophobic agent. The results show that the thermal conductivity and compressive strength of cellulose acetate aerogel with the best hydrophobic properties are 0.035 W m⁻¹ K⁻¹ at normal pressure and 0.39 MPa at 3% strain, respectively. This work shows that the highly hydrophobic cellulose acetate aerogel has potential as a waterproof material in the field of building thermal-insulation materials. Full article

(This article belongs to the Special Issue Gels as High-Performance Thermal Insulation Materials)

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14 pages, 1807 KiB

Open AccessArticle

An Investigation of the Sol-Gel Transition of Chitosan Lactate and Chitosan Chloride Solutions via Rheological and NMR Studies

by Katarzyna Pieklarz, Jacek Jenczyk, Zofia Modrzejewska, Piotr Owczarz and Stefan Jurga

Gels 2022, 8(10), 670; https://doi.org/10.3390/gels8100670 - 19 Oct 2022

Cited by 6 | Viewed by 2473

Abstract

In recent years, intensive research has been carried out on the use of hydrogels obtained from natural polymers, mainly chitosan. These products are increasingly replacing solutions based on synthetic materials in medicine. This publication presents the results of studies on the sol-gel transition [...] Read more.

In recent years, intensive research has been carried out on the use of hydrogels obtained from natural polymers, mainly chitosan. These products are increasingly replacing solutions based on synthetic materials in medicine. This publication presents the results of studies on the sol-gel transition of chitosan solutions as the base material for the preparation of thermosensitive hydrogels for potential applications in tissue engineering. The measurements were carried out for systems consisting of chitosan lactate and chitosan chloride solutions using β-glycerol phosphate disodium salt pentahydrate and uridine 5′-monophosphate disodium salt as the cross-linking agents. The sol-gel transition point of the solutions was determined based on the rheological measurements in the cone-plate configuration of the rotational rheometer and experiments performed using the method of nuclear magnetic resonance. The obtained results showed a significant influence of the cross-linking agent on the course of the sol-gel transition of chitosan salt solutions, and the systems that consisted of chitosan lactate seemed to be especially interesting for biomedical applications. Full article

(This article belongs to the Special Issue Hydrogel-Based Scaffolds with a Focus on Medical Use)

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11 pages, 2470 KiB

Open AccessArticle

Hydrolytic Stability of Crosslinked, Highly Alkaline Diallyldimethylammonium Hydroxide Hydrogels

by Tim B. Mrohs and Oliver Weichold

Gels 2022, 8(10), 669; https://doi.org/10.3390/gels8100669 - 19 Oct 2022

Cited by 2 | Viewed by 1584

Abstract

The aim of this study was to evaluate the persistence of alkaline hydrogels based on a common (N,N′-methylenebisacrylamide, BIS) and three recently published tetraallyl crosslinkers. Such hydrogels have been shown to be suitable materials for the rehabilitation of cementitious [...] Read more.

The aim of this study was to evaluate the persistence of alkaline hydrogels based on a common (N,N′-methylenebisacrylamide, BIS) and three recently published tetraallyl crosslinkers. Such hydrogels have been shown to be suitable materials for the rehabilitation of cementitious materials. Of the four crosslinkers under investigation, N,N,N′,N′-tetraallylpiperazinium dibromide decomposed quickly in 1 m KOH solution and was not considered further. BIS showed the first signs of a decomposition after several days, while tetraallylammonium bromide and N,N,N′,N′-tetraallyltrimethylene dipiperidine dibromide remained unaffected. In contrast to BIS, which suffers from low solubility in water, the two tetraallyl crosslinkers show unlimited miscibility with diallyldimethylammonium hydroxide solutions. For the study, gels with up to 50 wt % crosslinker were prepared. Of these, gels containing tetraallylammonium bromide always show the highest degrees of swelling, with a peak value of 397 g/g at a content of 2 wt %. Under accelerated ageing at 60 °C for 28 d, gels crosslinked with BIS ultimately turned liquid, while the storage modulus and the degree of swelling of the two tetraallyl-crosslinked gels remained unchanged. This indicates that alkaline gels can be suitable for long application periods, which are common for rehabilitation measures in the construction industry. Full article

(This article belongs to the Special Issue Advances in Smart and Tough Hydrogels)

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11 pages, 1931 KiB

Open AccessEditor’s ChoiceArticle

Thermoresponsive Cationic Polymers: PFAS Binding Performance under Variable pH, Temperature and Comonomer Composition

by E. Molly Frazar, Anicah Smith, Thomas Dziubla and J. Zach Hilt

Gels 2022, 8(10), 668; https://doi.org/10.3390/gels8100668 - 18 Oct 2022

Cited by 2 | Viewed by 3038

Abstract

The versatility and unique qualities of thermoresponsive polymeric systems have led to the application of these materials in a multitude of fields. One such field that can significantly benefit from the use of innovative, smart materials is environmental remediation. Of particular significance, multifunctional [...] Read more.

The versatility and unique qualities of thermoresponsive polymeric systems have led to the application of these materials in a multitude of fields. One such field that can significantly benefit from the use of innovative, smart materials is environmental remediation. Of particular significance, multifunctional poly(N-isopropylacrylamide) (PNIPAAm) systems based on PNIPAAm copolymerized with various cationic comonomers have the opportunity to target and attract negatively charged pollutants such as perfluorooctanoic acid (PFOA). The thermoresponsive cationic PNIPAAm systems developed in this work were functionalized with cationic monomers N-[3-(dimethylamino)propyl]acrylamide (DMAPA) and (3-acrylamidopropyl)trimethylammonium chloride (DMAPAQ). The polymers were examined for swelling capacity behavior and PFOA binding potential when exposed to aqueous environments with varying pH and temperature. Comonomer loading percentages had the most significant effect on polymer swelling behavior and temperature responsiveness as compared to aqueous pH. PFOA removal efficiency was greatly improved with the addition of DMAPA and DMAPAQ monomers. Aqueous pH and buffer selection were important factors when examining binding potential of the polymers, as buffered aqueous environments altered polymer PFOA removal quite drastically. The role of temperature on binding potential was not as expected and had no discernible effect on the ability of DMAPAQ polymers to remove PFOA. Overall, the cationic systems show interesting swelling behavior and significant PFOA removal results that can be explored further for potential environmental remediation applications. Full article

(This article belongs to the Special Issue Functionalized Gels for Environmental Applications)

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11 pages, 3030 KiB

Open AccessArticle

The Influence of Boron on the Structure and Properties of Hybrid Compounds Containing Zirconium and Phosphorus

by Petru Merghes, Gheorghe Ilia, Iosif Hulka, Vlad Chiriac, Narcis Varan and Vasile Simulescu

Gels 2022, 8(10), 667; https://doi.org/10.3390/gels8100667 - 17 Oct 2022

Viewed by 1641

Abstract

In the present work, novel organic–inorganic hybrid materials containing boron, zirconium, and phosphorus were synthesized at different molar ratios, using the sol–gel method, starting from zirconyl chloride hexa-hydrate, triethyl borate, and phenyl phosphonic acid as the precursors. The sol–gel process is used for [...] Read more.

In the present work, novel organic–inorganic hybrid materials containing boron, zirconium, and phosphorus were synthesized at different molar ratios, using the sol–gel method, starting from zirconyl chloride hexa-hydrate, triethyl borate, and phenyl phosphonic acid as the precursors. The sol–gel process is used for the first time in the present work in order to obtain organic–inorganic hybrids (or the so-called inorganic polymers) containing together boron, zirconium, and phosphorus. The sol–gel syntheses were performed at room temperature in ethanol. Zirconium containing compounds are already well known for their applications in medicine in restorative or prosthetic devices, including dental implants, knee and hip replacements, middle-ear ossicular chain reconstruction, and so on. Zirconium is a strong transition metal, which started to replace hafnium and titanium in the last decade in important applications. On the other hand, boron has the capability (similar to carbon) to form stable covalently bonded molecular networks. In addition to this capability, boron also offers mixed metallic and nonmetallic properties, because of its place on the periodic table, at the border between metals and nonmetals. Boron is responsible for the higher thermal stability of synthesized hybrid compounds. In the structure of those hybrid compounds, zirconium, boron, and phosphorus atoms are always connected via an oxygen atom, by P-O-Zr, Zr-O-Zr, or Zr-O-B bridges. Full article

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26 pages, 6727 KiB

Open AccessArticle

Biocompatible Self-Assembled Hydrogen-Bonded Gels Based on Natural Deep Eutectic Solvents and Hydroxypropyl Cellulose with Strong Antimicrobial Activity

by Daniela Filip, Doina Macocinschi, Mihaela Balan-Porcarasu, Cristian-Dragos Varganici, Raluca-Petronela Dumitriu, Dragos Peptanariu, Cristina Gabriela Tuchilus and Mirela-Fernanda Zaltariov

Gels 2022, 8(10), 666; https://doi.org/10.3390/gels8100666 - 17 Oct 2022

Cited by 6 | Viewed by 2690

Abstract

Natural deep eutectic solvents (NADES)-hydroxypropyl cellulose (HPC) self-assembled gels with potential for pharmaceutical applications are prepared. FT-IR, ¹HNMR, DSC, TGA and rheology measurements revealed that hydrogen bond acceptor–hydrogen bond donor interactions, concentration of NADES and the water content influence significantly the physico-chemical [...] Read more.

Natural deep eutectic solvents (NADES)-hydroxypropyl cellulose (HPC) self-assembled gels with potential for pharmaceutical applications are prepared. FT-IR, ¹HNMR, DSC, TGA and rheology measurements revealed that hydrogen bond acceptor–hydrogen bond donor interactions, concentration of NADES and the water content influence significantly the physico-chemical characteristics of the studied gel systems. HPC-NADES gel compositions have thermal stabilities lower than HPC and higher than NADES components. Thermal transitions reveal multiple glass transitions characteristic of phase separated systems. Flow curves evidence shear thinning (pseudoplastic) behavior. The flow curve shear stress vs. shear rate were assessed by applying Bingham, Herschel–Bulkley, Vocadlo and Casson rheological models. The proposed correlations are in good agreement with experimental data. The studied gels evidence thermothickening behavior due to characteristic LCST (lower critical solution temperature) behavior of HPC in aqueous systems and a good biocompatibility with normal cells (human gingival fibroblasts). The order of antibacterial and antifungal activities (S.aureus, E.coli, P. aeruginosa and C. albicans) is as follows: citric acid >lactic acid > urea > glycerol, revealing the higher antibacterial and antifungal activities of acids. Full article

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

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15 pages, 3989 KiB

Open AccessArticle

Characterization of Acid- and Pepsin-Soluble Collagen Extracted from the Skin of Purple-Spotted Bigeye Snapper

by Siti Nur Hazwani Oslan, Rossita Shapawi, Ruzaidi Azli Mohd Mokhtar, Wan Norhana Md. Noordin and Nurul Huda

Gels 2022, 8(10), 665; https://doi.org/10.3390/gels8100665 - 17 Oct 2022

Cited by 21 | Viewed by 3677

Abstract

Fish processing waste is a prospective source of collagen and a cost-effective environmental pollutant. The skin of the purple-spotted bigeye snapper (Priacanthus tayenus) was extracted utilising various acid soluble collagens (ASC) including acetic acid (AAC), lactic acid (LAC), citric acid (CAC) [...] Read more.

Fish processing waste is a prospective source of collagen and a cost-effective environmental pollutant. The skin of the purple-spotted bigeye snapper (Priacanthus tayenus) was extracted utilising various acid soluble collagens (ASC) including acetic acid (AAC), lactic acid (LAC), citric acid (CAC) and pepsin soluble collagens (PSC). In this study, PSC (6.65%) had the highest collagen yield, followed by AAC (5.79%), CAC (4.15%), and LAC (3.19%). The maximum temperatures (T_max) denaturation of AAC, LAC, CAC, and PSC were 31.4, 31.7, 31.5, and 33.2 °C, respectively. UV-VIS absorption spectra showed all extracted collagens had a range of absorbance at 230 nm, due to the presence of glycine, proline, hydroxyproline, and triple-helical collagen. Additionally, they exhibited amide A, B, amide I, II, and III peaks. SDS–PAGE identified all extracted collagens as type I. The PSC had a significantly higher (p < 0.05) hydroxyproline content than acidic extraction 66.3 ± 1.03 (mg/g sample). Furthermore, all samples were extremely soluble in acetic conditions at pH 5, and all collagen was soluble in NaCl up to 3% (w/v). Therefore, PSC was the best treatment since it did not impact collagen triple helical and acetic acid yielded the most collagen in ASC extraction. Overall, the analysis revealed that fish skin waste might be used as an alternate source of collagen in diverse applications, particularly in food applications. Full article

(This article belongs to the Special Issue Application of Hydrocolloids in Human Health and Nutrition)

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13 pages, 1502 KiB

Open AccessSystematic Review

Hydrogel on a Smart Nanomaterial Interface to Carry Therapeutics for Digitalized Glioma Treatment

by Xinyi Zhao, Bilal Javed, Furong Tian and Kangze Liu

Gels 2022, 8(10), 664; https://doi.org/10.3390/gels8100664 - 17 Oct 2022

Cited by 4 | Viewed by 2346

Abstract

Glioma is considered the primary brain tumor to cause brain illnesses, and it is difficult to treat and shows resistance to various routine therapeutics. The most common treatments to cure glioma are the surgical removal of tumors followed by adjuvant chemotherapy and radiation [...] Read more.

Glioma is considered the primary brain tumor to cause brain illnesses, and it is difficult to treat and shows resistance to various routine therapeutics. The most common treatments to cure glioma are the surgical removal of tumors followed by adjuvant chemotherapy and radiation therapy. The latest biocompatible interfaces have been incorporated into therapeutic modalities such as the targeted delivery of drugs using hydrogels to treat and manage brain glioma. This review illustrates the applications of the multimodal hydrogel as the carrier of therapeutics, gene therapy, therapeutic tactics, and glioma devices. The scientific articles were retrieved from 2019 to 2022 on Google Scholar and the Scopus database and screened to determine whether they were suitable for review. The 20 articles that fit the study are summarized in this review. These studies indicated that the sizes of the hydrogel range from 28 nm to 500 nm. There are 16 out of 20 articles that also explain the post-surgical application of hydrogels, and 13 out of 20 articles are employed in 3D culture and other structural manifestations of hydrogels. The pros of the hydrogel include the quick formulation for a sufficient filling of irregular damage sites, solubilizing hydrophobic drugs, continuously slowing drug release, provision of a 3D cell growth environment, improving efficacy, targetability of soluble biomolecules, increasing patient compliance, and decreased side effects. The cons of the hydrogel include difficult real-time monitoring, genetic manipulations, the cumbersome synchronized release of components, and lack of safety data. The prospects of the hydrogel may include the development of electronic hydrogel sensors that can be used to enhance guidance for the precise targeting patterns using patient-specific pathological idiosyncrasies. This technology has the potential to revolutionize the precision medicine approaches that would aid in the early detection and management of solid brain tumors. Full article

(This article belongs to the Special Issue Polymer Hydrogels for Cancer Therapy)

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27 pages, 6450 KiB

Open AccessReview

Chemical Overview of Gel Dosimetry Systems: A Comprehensive Review

by Micaela A. Macchione, Sofía Lechón Páez, Miriam C. Strumia, Mauro Valente and Facundo Mattea

Gels 2022, 8(10), 663; https://doi.org/10.3390/gels8100663 - 17 Oct 2022

Cited by 33 | Viewed by 3598

Abstract

Advances in radiotherapy technology during the last 25 years have significantly improved both dose conformation to tumors and the preservation of healthy tissues, achieving almost real-time feedback by means of high-precision treatments and theranostics. Owing to this, developing high-performance systems capable of coping [...] Read more.

Advances in radiotherapy technology during the last 25 years have significantly improved both dose conformation to tumors and the preservation of healthy tissues, achieving almost real-time feedback by means of high-precision treatments and theranostics. Owing to this, developing high-performance systems capable of coping with the challenging requirements of modern ionizing radiation is a key issue to overcome the limitations of traditional dosimeters. In this regard, a deep understanding of the physicochemical basis of gel dosimetry, as one of the most promising tools for the evaluation of 3D high-spatial-resolution dose distributions, represents the starting point for developing new and innovative systems. This review aims to contribute thorough descriptions of the chemical processes and interactions that condition gel dosimetry outputs, often phenomenologically addressed, and particularly formulations reported since 2017. Full article

(This article belongs to the Special Issue Gel Dosimetry)

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17 pages, 4192 KiB

Open AccessArticle

Mechanical Properties of Polyvinyl Alcohol Fiber-Reinforced Cementitious Composites after High-Temperature Exposure

by Peng Zhang, Peishuo Zhang, Jingjiang Wu, Yong Zhang and Jinjun Guo

Gels 2022, 8(10), 662; https://doi.org/10.3390/gels8100662 - 17 Oct 2022

Cited by 11 | Viewed by 2818

Abstract

The mechanical properties of cementitious composites before and after exposure to high temperature are affected by calcium–silicate–hydrate (C–S–H) gels. To evaluate the effects of high temperature, plyvinyl alcohol (PVA) fiber content, and the cooling method on properties of cementitious composites, physical, mechanical, and [...] Read more.

The mechanical properties of cementitious composites before and after exposure to high temperature are affected by calcium–silicate–hydrate (C–S–H) gels. To evaluate the effects of high temperature, plyvinyl alcohol (PVA) fiber content, and the cooling method on properties of cementitious composites, physical, mechanical, and microscopic tests were performed in this study. The target temperatures were 25, 100, 200, 300, 400, 600, and 800 °C. The PVA fiber contents were 0.0, 0.3, 0.6, 0.9, 1.2, and 1.5 vol%. The high-temperature resistance of PVA fiber-reinforced cementitious composite (PVA-FRCC) specimens was investigated through changes in their appearance, mass loss, compressive strength, splitting tensile strength, flexural strength, and microstructure. The results showed that PVA fibers reduced the probability of explosion spalling in the PVA-FRCC specimens exposed to high temperatures. The mass loss rate of samples exposed to temperatures below 200 °C was small and lower than 5%, whereas a significant mass loss was observed at 200 °C to 800 °C. A small rise in the cubic compressive and splitting tensile strengths of samples was found at 400 °C and 300 °C, respectively. Below 400 °C, the fibers were beneficial to the mechanical strength of the PVA-FRCC specimens. Nevertheless, when the temperature was heated above 400 °C, melted fibers created many pores and channels, which caused a decrease in the strength of the specimens. The method of cooling with water could aggravate the damage to the cementitious composites exposed to temperatures above 200 °C. High temperature could lead to the decomposition of the C–S–H gels of the PVA-FRCC samples, which makes C–S–H gels lose their bonding ability. From the perspective of the microstructure, the structure of PVA-FRCC samples exposed to 600 °C and 800 °C became loose and the number of microcracks increased, which confirmed the reduction in macro-mechanical properties. Full article

(This article belongs to the Special Issue Geopolymer Gels for Next-Generation Construction)

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17 pages, 6682 KiB

Open AccessEditor’s ChoiceArticle

A Multifractal Vision of 5-Fluorouracil Release from Chitosan-Based Matrix

by Maria-Alexandra Paun, Vladimir-Alexandru Paun and Viorel-Puiu Paun

Gels 2022, 8(10), 661; https://doi.org/10.3390/gels8100661 - 16 Oct 2022

Cited by 5 | Viewed by 1778

Abstract

A suite of four drug deliverance formulations grounded on 5-fluorouracil enclosed in a chitosan-founded intercellular substance was produced by 3,7-dimethyl-2,6-octadienal with in situ hydrogelation. The formulations have been examined from a morphological and structural point of view by Fourier transform infrared (FTIR) spectroscopy [...] Read more.

A suite of four drug deliverance formulations grounded on 5-fluorouracil enclosed in a chitosan-founded intercellular substance was produced by 3,7-dimethyl-2,6-octadienal with in situ hydrogelation. The formulations have been examined from a morphological and structural point of view by Fourier transform infrared (FTIR) spectroscopy and microscopy with polarized light, respectively. The polarized optical microscopy (POM) pictures of the three representative formulations obtained were investigated by fractal analysis. The fractal dimension and lacunarity of each of them were thus calculated. In this paper, a novel theoretical method for mathematically describing medicament deliverance dynamics in the context of the polymeric medicament constitution limit has been advanced. Assuming that the polymeric drug motion unfolds only on the so-called non-differentiable curves (considered mathematically multifractal curves), it looks like in a one-dimensional hydrodynamic movement within a multifractal formalism, the drug-release physics models are provided by isochronous kinetics, but at a scale of resolution necessarily non-differentiable. Full article

(This article belongs to the Special Issue Gels: Synthesis, Characterization and Applications in High Performance Chemistry)

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14 pages, 1679 KiB

Open AccessArticle

Hydrogels, Oleogels and Bigels as Edible Coatings of Sardine Fillets and Delivery Systems of Rosemary Extract

by Aikaterini Kanelaki, Konstantina Zampouni, Ioannis Mourtzinos and Eugenios Katsanidis

Gels 2022, 8(10), 660; https://doi.org/10.3390/gels8100660 - 16 Oct 2022

Cited by 23 | Viewed by 2742

Abstract

Edible coatings provide an alternative way to reduce packaging requirements and extend the shelf life of foods by delaying oxidation and microbial spoilage. Hydrogels, oleogels and bigels were applied as coatings on fresh sardine fillets. The effectiveness of these coatings as delivery systems [...] Read more.

Edible coatings provide an alternative way to reduce packaging requirements and extend the shelf life of foods by delaying oxidation and microbial spoilage. Hydrogels, oleogels and bigels were applied as coatings on fresh sardine fillets. The effectiveness of these coatings as delivery systems of rosemary extract (RE) was also evaluated. Three groups of sardine fillet treatments were prepared: (i) the control (C), which comprised sardine fillets without coating, (ii) sardine fillets with plain hydrogel (H), oleogel (O) or bigel (BG) coatings, and (iii) sardine fillets with RE incorporated into the H, O and BG coatings. The different treatments were evaluated for lipid oxidation (TBA test), total volatile basic nitrogen (TVB-N) and microbiological growth during cold storage at 4 °C. Results showed that hydrogel, oleogel and bigel coatings delayed oxidation. The incorporation of RE into coatings significantly retarded lipid oxidation but did not affect the proliferation of microorganisms during storage. When RE was incorporated in the oleogel phase of the bigel coating, it produced significantly lower TVB-N values compared to the control and BG treatments. The incorporation of RE into the oleogel phase of the bigel coating may be a promising method of maintaining the storage quality of the sardine fillets stored at refrigerated temperatures. Full article

(This article belongs to the Special Issue Application of Oleogel and Oleogel-Based Systems in Foods: Effective Strategies to Satisfy People's Demands for Nutrition and Health)

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13 pages, 5924 KiB

Open AccessArticle

Osmanthus Fragrans Loaded NIPAAM Hydrogel Promotes Osteogenic Differentiation of MC3T3-E1

by Bin Huang, Mengyao Zhao, Mingzhe Yang, Lu Rao, Chizhou Wu, Yuzhu Hu, Huangqin Chen and Yuesheng Li

Gels 2022, 8(10), 659; https://doi.org/10.3390/gels8100659 - 15 Oct 2022

Cited by 2 | Viewed by 2000

Abstract

There is an urgent need to find long-acting, natural osteogenesis-promoting drug systems. In this study, first the potential targets and mechanism of osmanthus fragrans (O. fragrans) extract in regulating osteogenic differentiation based on autophagy were analyzed by network pharmacology and molecular docking. Then, [...] Read more.

There is an urgent need to find long-acting, natural osteogenesis-promoting drug systems. In this study, first the potential targets and mechanism of osmanthus fragrans (O. fragrans) extract in regulating osteogenic differentiation based on autophagy were analyzed by network pharmacology and molecular docking. Then, osmanthus fragrans was extracted using the ethanol reflux method and an osmanthus fragrans extract loaded Poly N-isopropylacrylamide (OF/NIPAAM) hydrogel was prepared by electron beam radiation. The chemical components of the osmanthus fragrans extract and the microstructure of OF/NIPAAM hydrogels were characterized by ultraviolet-visible spectrophotometry (UV-Vis) and X-ray diffraction (XRD), respectively. Mouse embryonic osteoblast precursor cells MC3T3-E1 were cultured with different concentrations of OF/NIPAAM hydrogel to discover cell proliferation activity by CCK-8 assay. Alkaline phosphatase (ALP) staining and alizarin red staining were used to observe the differentiation and calcification. Through experimental exploration, we found that a total of 11 targets were predicted, which are TP53, CASP3, SIRT1, etc., and osmanthus fragrans had good binding activity to TP53. In vitro, except for proliferation promotion, OF/NIPAAM hydrogel enhanced ALP activity and formation of mineralized nodules of MC3T3-E1 cells at a concentration equal to or less than 62.5 μg/mL (p < 0.05). The addition of autophagy inhibitor 3-methyladenine (3-MA) reduced ALP activity and mineralized nodule formation. Full article

(This article belongs to the Special Issue Gels in Medicine and Pharmacological Therapies)

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14 pages, 5610 KiB

Open AccessArticle

Acceleration of Wound Healing in Rats by Modified Lignocellulose Based Sponge Containing Pentoxifylline Loaded Lecithin/Chitosan Nanoparticles

by Pouya Dehghani, Aliakbar Akbari, Milad Saadatkish, Jaleh Varshosaz, Monireh Kouhi and Mahdi Bodaghi

Gels 2022, 8(10), 658; https://doi.org/10.3390/gels8100658 - 15 Oct 2022

Cited by 3 | Viewed by 2355

Abstract

Dressing wounds accelerates the re-epithelialization process and changes the inflammatory environment towards healing. In the current study, a lignocellulose sponge containing pentoxifylline (PTX)-loaded lecithin/chitosan nanoparticles (LCNs) was developed to enhance the wound healing rate. Lecithin/chitosan nanoparticles were obtained by the solvent-injection method and [...] Read more.

Dressing wounds accelerates the re-epithelialization process and changes the inflammatory environment towards healing. In the current study, a lignocellulose sponge containing pentoxifylline (PTX)-loaded lecithin/chitosan nanoparticles (LCNs) was developed to enhance the wound healing rate. Lecithin/chitosan nanoparticles were obtained by the solvent-injection method and characterized in terms of morphology, particle size distribution, and zeta potential. The lignocellulose hydrogels were functionalized through oxidation/amination and freeze-dried to obtain sponges. The prepared sponge was then loaded with LCNs/PTX to control drug release. The nanoparticle containing sponges were characterized using FTIR and SEM analysis. The drug release study from both nanoparticles and sponges was performed in PBS at 37 °C at different time points. The results demonstrated that PTX has sustained release from lignocellulose hydrogels. The wound healing was examined using a standard rat model. The results exhibited that PTX loaded hydrogels could achieve significantly accelerated and enhanced healing compared to the drug free hydrogels and the normal saline treatment. Histological examination of the healed skin confirmed the visual observations. Overall speaking, the in vivo assessment of the developed sponge asserts its suitability as wound dressing for treatment of chronic skin wounds. Full article

(This article belongs to the Special Issue Design of Polymeric Hydrogels Biomaterials)

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31 pages, 8071 KiB

Open AccessArticle

Self-Healing and Super-Elastomeric PolyMEA-co-SMA Nanocomposites Crosslinked by Clay Platelets

by Beata Strachota, Adam Strachota, Katarzyna Byś, Ewa Pavlova, Jiří Hodan and Beata Mossety-Leszczak

Gels 2022, 8(10), 657; https://doi.org/10.3390/gels8100657 - 15 Oct 2022

Cited by 2 | Viewed by 1933

Abstract

Novel solvent-free ultra-extensible, tough, and self-healing nanocomposite elastomers were synthesized. The self-assembled materials were based on the copolymer matrix poly(methoxyethyl acrylate-co-sodium methacrylate) physically crosslinked by clay nano-platelets (‘poly[MEA-co-SMA]/clay’). Depending on the content of SMA, the super-elastomers were predominantly hydrophobic, water-swelling, or fully water-soluble, [...] Read more.

Novel solvent-free ultra-extensible, tough, and self-healing nanocomposite elastomers were synthesized. The self-assembled materials were based on the copolymer matrix poly(methoxyethyl acrylate-co-sodium methacrylate) physically crosslinked by clay nano-platelets (‘poly[MEA-co-SMA]/clay’). Depending on the content of SMA, the super-elastomers were predominantly hydrophobic, water-swelling, or fully water-soluble, and hence repeatedly processible. The SMA co-monomer introduces a tremendous increase in tensile strength, an increase in toughness, while ultra-extensibility is preserved. By tuning the contents of nano-clay and SMA co-monomer, a very wide range of product properties was achieved, including extreme ultra-extensibility, or high stiffness combined with more moderate super-extensibility, or very different values of tensile strength. There was very attractive, great improvement in autonomous self-healing ability induced by SMA, combined with tremendously enhanced self-recovery of internal mechanical damage: even complete self-recovery could be achieved. The ionic SMA repeat units were found to assemble to multiplets, which are phase-separated in the hydrophobic polyMEA matrix. The dynamics of SMA-units-hopping between these aggregates was of key importance for the mechanical, visco-elastic, tensile, and self-healing properties. The studied super-elastomers are attractive as advanced self-healing materials in engineering, soft robotics, and in medical or implant applications. Full article

(This article belongs to the Special Issue Self-Healing Hydrogels for Applications in Regenerative Medicine)

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13 pages, 2882 KiB

Open AccessArticle

Water Desalination Using Polyelectrolyte Hydrogel: Gibbs Ensemble Modeling

by Mikhail Laktionov, Lucie Nová and Oleg V. Rud

Gels 2022, 8(10), 656; https://doi.org/10.3390/gels8100656 - 15 Oct 2022

Cited by 4 | Viewed by 1905

Abstract

Polyelectrolyte hydrogels can absorb a large amount of water across an osmotic membrane as a result of their swelling pressure. On the other hand, the insoluble cross-linked hydrogel network enables dewatering under the influence of external (thermal and/or mechanical) stimuli. Moreover, from a [...] Read more.

Polyelectrolyte hydrogels can absorb a large amount of water across an osmotic membrane as a result of their swelling pressure. On the other hand, the insoluble cross-linked hydrogel network enables dewatering under the influence of external (thermal and/or mechanical) stimuli. Moreover, from a thermodynamic perspective, a polyelectrolyte hydrogel is already an osmotic membrane. These properties designate hydrogels as excellent candidates for use in desalination, at the same time avoiding the use of expensive membranes. In this article, we present our recent theoretical study of polyelectrolyte hydrogel usage for water desalination. Employing a coarse-grained model and the Gibbs ensemble, we modeled the thermodynamic equilibrium between the coexisting gel phase and the supernate aqueous salt solution phase. We performed a sequence of step-by-step hydrogel swellings and compressions in open and closed systems, i.e., in equilibrium with a large and with a comparably small reservoir of aqueous solution. The swelling in an open system removes ions from the large reservoir, whereas the compression in a closed system decreases the salt concentration in the small reservoir. We modeled this stepwise process of continuous decrease of water salinity from seawater up to freshwater concentrations and estimated the energy cost of the process to be comparable to that of reverse osmosis. Full article

(This article belongs to the Section Gel Applications)

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12 pages, 1437 KiB

Open AccessArticle

Solubility Enhancement, Formulation Development, and Antibacterial Activity of Xanthan-Gum-Stabilized Colloidal Gold Nanogel of Hesperidin against Proteus vulgaris

by Aftab Alam, Talha Jawaid, Saud M. Alsanad, Mehnaz Kamal, Pinki Rawat, Vinita Singh, Pravej Alam and Prawez Alam

Gels 2022, 8(10), 655; https://doi.org/10.3390/gels8100655 - 14 Oct 2022

Cited by 14 | Viewed by 2236

Abstract

The objective of the study was to develop a transdermal nanoformulation of hesperidin (HSP) against Proteus vulgaris (P. vulgaris). Based on the low water solubility of HSP, we prepared HSP-enabled AuNPs stabilized with xanthan gum (XA), referred to as HSP@XA@AuNPs. The [...] Read more.

The objective of the study was to develop a transdermal nanoformulation of hesperidin (HSP) against Proteus vulgaris (P. vulgaris). Based on the low water solubility of HSP, we prepared HSP-enabled AuNPs stabilized with xanthan gum (XA), referred to as HSP@XA@AuNPs. The HSP@XA@AuNP formulation was evaluated for particle size (43.16 nm), PDI (0.565), zeta potential (−31.9 mV), and entrapment efficiency (56.7%). The HSP@XA@AuNPs gel was developed by incorporating selected formulation grades into a 1% Carbopol gel base and characterized by physical evaluation and rheological studies. The color of the HSP@XA@AuNP gel was light pink, and the texture was very smooth and non-greasy. The gel was shown to be odorless. A field emission scanning electron microscope (FESEM) was used to investigate the shape of HSP@XA@AuNPs further. The drug release was 73.08% for the HSP@XA@AuNPs and 86.26% for the HSP@XA@AuNPs gel in 500 min. The prepared gel showed antimicrobial activity against P. vulgaris with an MIC of 1.78 μg/mL. In conclusion, the HSP@XA@AuNPs gel could be an advanced modality for treating P. vulgaris. Full article

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