Gels | Special Issue : Supramolecular/Supramolecular Hybrid Hydrogel

Research

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13 pages, 3268 KiB

Open AccessArticle

Significant Interfacial Dielectric Relaxation of Covalently Bonded Ice-Hydrogels

by Yongqiang Li, Liufang Chen, Chuanfu Li, Lin Lin, Zhibo Yan and Junming Liu

Gels 2022, 8(7), 409; https://doi.org/10.3390/gels8070409 - 28 Jun 2022

Cited by 1 | Viewed by 1455

Abstract

Hydrogels are composed of a three-dimensional network of cross-linked hydrophilic polymer chains and large amounts of water. The physicochemical properties of the polymer-water interface in hydrogels draw our attention. Due to the complex structure of hydrogel systems, it is still a challenge to [...] Read more.

Hydrogels are composed of a three-dimensional network of cross-linked hydrophilic polymer chains and large amounts of water. The physicochemical properties of the polymer-water interface in hydrogels draw our attention. Due to the complex structure of hydrogel systems, it is still a challenge to investigate the interfacial layer properties of hydrogels through experiments. In this work, we investigate the properties of the covalently bonded chitosan-based ice-hydrogels interfacial layer by dielectric relaxation spectroscopy (DRS) techniques in the presence of avoided electrode polarization. The DRS data exhibit that the polymer-water interfacial layer has a strong dielectric signal response, which indicates that a large number of polar electric dipoles or polar molecules may be contained in the interfacial layer. The variable temperature dielectric relaxation behavior of a series of chitosan-base ice-hydrogels showed that the value of dielectric activation energy for different water contents is about 180 kJ/mol, which is much larger than that of the polymer and ice phases, suggesting a strong coupling of polar electric dipoles within the interfacial layer. This work demonstrates the important role of the polymer-water interface in covalently bonded hydrogels, which will provide assistance in the design and application of covalently bonded hydrogels. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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18 pages, 5696 KiB

Open AccessArticle

Study of Several Alginate-Based Hydrogels for In Vitro 3D Cell Cultures

by Weijie Jiao, Xiaohong Li, Jingxin Shan and Xiaohong Wang

Gels 2022, 8(3), 147; https://doi.org/10.3390/gels8030147 - 27 Feb 2022

Cited by 6 | Viewed by 2923

Abstract

Hydrogel, a special system of polymer solutions, can be obtained through the physical/chemical/enzymic crosslinking of polymer chains in a water-based dispersion medium. Different compositions and crosslinking methods endow hydrogel with diverse physicochemical properties. Those hydrogels with suitable physicochemical properties hold manifold functions in [...] Read more.

Hydrogel, a special system of polymer solutions, can be obtained through the physical/chemical/enzymic crosslinking of polymer chains in a water-based dispersion medium. Different compositions and crosslinking methods endow hydrogel with diverse physicochemical properties. Those hydrogels with suitable physicochemical properties hold manifold functions in biomedical fields, such as cell transplantation, tissue engineering, organ manufacturing, drug releasing and pathological model analysis. In this study, several alginate-based composite hydrogels, including gelatin/alginate (G-A), gelatin/alginate/agarose (G-A-A), fibrinogen/alginate (F-A), fibrinogen/alginate/agarose (F-A-A) and control alginate (A) and alginate/agarose (A-A), were constructed. We researched the advantages and disadvantages of these hydrogels in terms of their microscopic structure (cell living space), water holding capacity, swelling rate, swelling–erosion ratio, mechanical properties and biocompatibility. Briefly, alginate-based hydrogels can be used for three-dimensional (3D) cell culture alone. However, when mixed with other natural polymers in different proportions, a relatively stable network with a good cytocompatibility, mechanical strength and water holding capacity can be formed. The physical and chemical properties of the hydrogels can be adjusted by changing the composition, proportion and cross-linking methods of the polymers. Conclusively, the G-A-A and F-A-A hydrogels are the best hydrogels for the in vitro 3D cell cultures and pathological model construction. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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19 pages, 59469 KiB

Open AccessArticle

GOx/Hb Cascade Oxidized Crosslinking of Silk Fibroin for Tissue-Responsive Wound Repair

by Hongdou Shen, Pei Wang, Xiaoke Han, Mengli Ma, Yinghui Shang, Ye Ju, Saiji Shen, Feng Yin and Qigang Wang

Gels 2022, 8(1), 56; https://doi.org/10.3390/gels8010056 - 12 Jan 2022

Cited by 4 | Viewed by 3074

Abstract

Promising wound dressings can achieve rapid soft-tissue filling while refactoring the biochemical and biophysical microenvironment to recruit endogenous cells, facilitating tissue healing, integration, and regeneration. In this study, a tissue biomolecule-responsive hydrogel matrix, employing natural silk fibroin (SF) as a functional biopolymer and [...] Read more.

Promising wound dressings can achieve rapid soft-tissue filling while refactoring the biochemical and biophysical microenvironment to recruit endogenous cells, facilitating tissue healing, integration, and regeneration. In this study, a tissue biomolecule-responsive hydrogel matrix, employing natural silk fibroin (SF) as a functional biopolymer and haemoglobin (Hb) as a peroxidase-like biocatalyst, was fabricated through cascade enzymatic crosslinking. The hydrogels possessed mechanical tunability and displayed adjustable gelation times. A tyrosine unit on SF stabilised the structure of Hb during the cascade oxidation process; thus, the immobilized Hb in SF hydrogels exhibited higher biocatalytic efficiency than the free enzyme system, which provided a continuously antioxidative system. The regulation of the dual enzyme ratio endowed the hydrogels with favourable biocompatibility, biodegradability, and adhesion strength. These multifunctional hydrogels provided a three-dimensional porous extracellular matrix-like microenvironment for promoting cell adhesion and proliferation. A rat model with a full-thickness skin defect revealed accelerated wound regeneration via collagen deposition, re-epithelialisation and revascularisation. Enzyme-loaded hydrogels are an attractive and high-safety biofilling material with the potential for wound healing, tissue regeneration, and haemostasis. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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12 pages, 2384 KiB

Open AccessArticle

Regulating the Homogeneity of Thiol-Maleimide Michael-Type Addition-Based Hydrogels Using Amino Biomolecules

by Yu Guo, Jie Gu, Yuxin Jiang, Yanyan Zhou, Zhenshu Zhu, Tingting Ma, Yuanqi Cheng, Zongzhou Ji, Yonghua Jiao, Bin Xue and Yi Cao

Gels 2021, 7(4), 206; https://doi.org/10.3390/gels7040206 - 11 Nov 2021

Cited by 8 | Viewed by 3126

Abstract

Poly(ethylene glycol) (PEG)-based synthetic hydrogels based on Michael-type addition reaction have been widely used for cell culture and tissue engineering. However, recent studies showed that these types of hydrogels were not homogenous as expected since micro domains generated due to the fast reaction [...] Read more.

Poly(ethylene glycol) (PEG)-based synthetic hydrogels based on Michael-type addition reaction have been widely used for cell culture and tissue engineering. However, recent studies showed that these types of hydrogels were not homogenous as expected since micro domains generated due to the fast reaction kinetics. Here, we demonstrated a new kind of method to prepare homogenous poly(ethylene glycol) hydrogels based on Michael-type addition using the side chain amine-contained short peptides. By introducing such a kind of short peptides, the homogeneity of crosslinking and mechanical property of the hydrogels has been also significantly enhanced. The compressive mechanical and recovery properties of the homogeneous hydrogels prepared in the presence of side chain amine-contained short peptides were more reliable than those of inhomogeneous hydrogels while the excellent biocompatibility remained unchanged. Furthermore, the reaction rate and gelation kinetics of maleimide- and thiol-terminated PEG were proved to be significantly slowed down in the presence of the side chain amine-contained short peptides, thus leading to the improved homogeneity of the hydrogels. We anticipate that this new method can be widely applied to hydrogel preparation and modification based on Michael-type addition gelation. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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13 pages, 4166 KiB

Open AccessArticle

Injectable and Antioxidative HT/QGA Hydrogel for Potential Application in Wound Healing

by Yikun Ren, Dan Zhang, Yuanmeng He, Rong Chang, Shen Guo, Shanshan Ma, Minghao Yao and Fangxia Guan

Gels 2021, 7(4), 204; https://doi.org/10.3390/gels7040204 - 9 Nov 2021

Cited by 17 | Viewed by 2603 | Correction

Abstract

Hydrogels have gained a niche in the market as wound dressings due to their high water content and plasticity. However, traditional hydrogel wound dressings are difficult to fully adapt to irregular-shaped wound areas. Additionally, excessive reactive oxygen species (ROS) accumulated in the damaged [...] Read more.

Hydrogels have gained a niche in the market as wound dressings due to their high water content and plasticity. However, traditional hydrogel wound dressings are difficult to fully adapt to irregular-shaped wound areas. Additionally, excessive reactive oxygen species (ROS) accumulated in the damaged area impede the wound healing process. Therefore, hydrogels with injectable and antioxidant properties offer promising qualities for wound healing, but their design and development remain challenges. In this study, HT/QGA (tyramine-grafted hyaluronic acid/gallic acid-grafted quaternized chitosan) hydrogels with injectable and antioxidant properties were prepared and characterized. This hydrogel exhibited excellent injectability, favorable antioxidant activity, and good biocompatibility. Moreover, we evaluated the therapeutic effect of HT/QGA hydrogel in a full-thickness skin injury model. These results suggested that HT/QGA hydrogel may offer a great potential application in wound healing. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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13 pages, 50950 KiB

Open AccessArticle

In Situ Synthesis of Magnetic Poly(DMAEAB-co-NIPAm)@Fe₃O₄ Composite Hydrogel for Removal of Dye from Water

by Zhi Chen, Xia Song, Wilson Wee Mia Soh, Yuting Wen, Jingling Zhu, Miao Zhang and Jun Li

Gels 2021, 7(4), 201; https://doi.org/10.3390/gels7040201 - 5 Nov 2021

Cited by 7 | Viewed by 1991

Abstract

Water pollution by toxic substances, such as dye molecules, remains a major environmental problem that needs to be solved. In the present work, the magnetic composite hydrogel based on the poly(2-(methacryloyloxy)-N-(2-hydroxyethyl)-N,N-dimethylethan-1-aminium bromide-co-N-isopropylacrylamide) copolymer with incorporated [...] Read more.

Water pollution by toxic substances, such as dye molecules, remains a major environmental problem that needs to be solved. In the present work, the magnetic composite hydrogel based on the poly(2-(methacryloyloxy)-N-(2-hydroxyethyl)-N,N-dimethylethan-1-aminium bromide-co-N-isopropylacrylamide) copolymer with incorporated Fe₃O₄ particles ((poly(DMAEAB-co-NIPAm)@Fe₃O₄)) was prepared by an in situ synthesis technique for the efficient removal of dye molecules from water. The successfully synthesized magnetic hydrogel was characterized by FTIR, XRD, TGA, and TEM. The removal efficiency of the anionic dye bromophenol blue (BPB) and the cationic dye rhodamine B (RDM) by the prepared hydrogel adsorbents was evaluated. Various adsorption parameters, including the concentration of adsorbents and adsorption time, were also investigated. The results showed that the synthesized magnetic hydrogel had excellent BPB removal performance compared to the removal of RDM. The optimum adsorbent concentration for 0.5 mM BPB solution was approximately 0.5 g/L, and the removal efficiency was more than 99%. The kinetics data of BPB removal fitted well into the pseudo-2nd-order model, indicating that BPB dye adsorption involves chemical adsorption and physical adsorption. In addition, recycling studies were conducted to examine the reusability of the magnetic hydrogel for BPB removal for up to five cycles and the hydrogel could be reused without losing its high removal efficiency. The magnetic hydrogel poly(DMAEAB-co-NIPAm)@Fe₃O₄ with high removal efficiency, good selectivity, and reusability shows great potential for the removal of anionic dyes in wastewater treatment. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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13 pages, 3359 KiB

Open AccessArticle

Polypeptide Composition and Topology Affect Hydrogelation of Star-Shaped Poly(_L-lysine)-Based Amphiphilic Copolypeptides

by Thi Ha My Phan, Ching-Chia Huang, Yi-Jen Tsai, Jin-Jia Hu and Jeng-Shiung Jan

Gels 2021, 7(3), 131; https://doi.org/10.3390/gels7030131 - 30 Aug 2021

Cited by 10 | Viewed by 2536

Abstract

In this research, we studied the effect of polypeptide composition and topology on the hydrogelation of star-shaped block copolypeptides based on hydrophilic, coil poly(_L-lysine)₂₀ (s-PLL₂₀) tethered with a hydrophobic, sheet-like polypeptide segment, which is poly(_L [...] Read more.

In this research, we studied the effect of polypeptide composition and topology on the hydrogelation of star-shaped block copolypeptides based on hydrophilic, coil poly(_L-lysine)₂₀ (s-PLL₂₀) tethered with a hydrophobic, sheet-like polypeptide segment, which is poly(_L-phenylalanine) (PPhe), poly(_L-leucine) (PLeu), poly(_L-valine) (PVal) or poly(_L-alanine) (PAla) with a degree of polymerization (DP) about 5. We found that the PPhe, PLeu, and PVal segments are good hydrogelators to promote hydrogelation. The hydrogelation and hydrogel mechanical properties depend on the arm number and hydrophobic polypeptide segment, which are dictated by the amphiphilic balance between polypeptide blocks and the hydrophobic interactions/hydrogen bonding exerted by the hydrophobic polypeptide segment. The star-shaped topology could facilitate their hydrogelation due to the branching chains serving as multiple interacting depots between hydrophobic polypeptide segments. The 6-armed diblock copolypeptides have better hydrogelation ability than 3-armed ones and s-PLL-b-PPhe exhibits better hydrogelation ability than s-PLL-b-PVal and s-PLL-b-PLeu due to the additional cation–π and π–π interactions. This study highlights that polypeptide composition and topology could be additional parameters to manipulate polypeptide hydrogelation. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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Review

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20 pages, 3077 KiB

Open AccessReview

Bone Regeneration Using MMP-Cleavable Peptides-Based Hydrogels

by Weikai Chen, Ziyang Zhou, Dagui Chen, Yinghua Li, Qin Zhang and Jiacan Su

Gels 2021, 7(4), 199; https://doi.org/10.3390/gels7040199 - 5 Nov 2021

Cited by 20 | Viewed by 4174

Abstract

Accumulating evidence has suggested the significant potential of chemically modified hydrogels in bone regeneration. Despite the progress of bioactive hydrogels with different materials, structures and loading cargoes, the desires from clinical applications have not been fully validated. Multiple biological behaviors are orchestrated precisely [...] Read more.

Accumulating evidence has suggested the significant potential of chemically modified hydrogels in bone regeneration. Despite the progress of bioactive hydrogels with different materials, structures and loading cargoes, the desires from clinical applications have not been fully validated. Multiple biological behaviors are orchestrated precisely during the bone regeneration process, including bone marrow mesenchymal stem cells (BMSCs) recruitment, osteogenic differentiation, matrix calcification and well-organized remodeling. Since matrix metalloproteinases play critical roles in such bone metabolism processes as BMSC commitment, osteoblast survival, osteoclast activation matrix calcification and microstructure remodeling, matrix metalloproteinase (MMP) cleavable peptides-based hydrogels could respond to various MMP levels and, thus, accelerate bone regeneration. In this review, we focused on the MMP-cleavable peptides, polymers, functional modification and crosslinked reactions. Applications, perspectives and limitations of MMP-cleavable peptides-based hydrogels for bone regeneration were then discussed. Full article

(This article belongs to the Special Issue Supramolecular/Supramolecular Hybrid Hydrogel)

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