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Journal articles on the topic 'Hydrogel'
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1
Li, Zhangkang, Cheng Yu, Hitendra Kumar, Xiao He, Qingye Lu, Huiyu Bai, Keekyoung Kim, and Jinguang Hu. "The Effect of Crosslinking Degree of Hydrogels on Hydrogel Adhesion." Gels 8, no. 10 (October 21, 2022): 682. http://dx.doi.org/10.3390/gels8100682.
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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.
2
Lee, Celine, He-Shin Huang, Yun-Ying Wang, You-Sheng Zhang, Rajan Deepan Chakravarthy, Mei-Yu Yeh, Hsin-Chieh Lin, and Jeng Wei. "Stretchable, Adhesive, and Biocompatible Hydrogel Based on Iron–Dopamine Complexes." Polymers 15, no. 22 (November 10, 2023): 4378. http://dx.doi.org/10.3390/polym15224378.
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Hydrogels’ exceptional mechanical strength and skin-adhesion characteristics offer significant advantages for various applications, particularly in the fields of tissue adhesion and wearable sensors. Herein, we incorporated a combination of metal-coordination and hydrogen-bonding forces in the design of stretchable and adhesive hydrogels. We synthesized four hydrogels, namely PAID-0, PAID-1, PAID-2, and PAID-3, consisting of acrylamide (AAM), N,N′-methylene-bis-acrylamide (MBA), and methacrylic-modified dopamine (DA). The impact of different ratios of iron (III) ions to DA on each hydrogel’s performance was investigated. Our results demonstrate that the incorporation of iron–dopamine complexes significantly enhances the mechanical strength of the hydrogel. Interestingly, as the DA content increased, we observed a continuous and substantial improvement in both the stretchability and skin adhesiveness of the hydrogel. Among the hydrogels tested, PAID-3, which exhibited optimal mechanical properties, was selected for adhesion testing on various materials. Impressively, PAID-3 demonstrated excellent adhesion to diverse materials and, combined with the low cytotoxicity of PAID hydrogel, holds great promise as an innovative option for biomedical engineering applications.
3
Wang, Xinyu, Huiyuan Wang, Hongmin Zhang, Tianxi Yang, Bin Zhao, and Juan Yan. "Investigation of the Impact of Hydrogen Bonding Degree in Long Single-Stranded DNA (ssDNA) Generated with Dual Rolling Circle Amplification (RCA) on the Preparation and Performance of DNA Hydrogels." Biosensors 13, no. 7 (July 23, 2023): 755. http://dx.doi.org/10.3390/bios13070755.
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DNA hydrogels have gained significant attention in recent years as one of the most promising functional polymer materials. To broaden their applications, it is critical to develop efficient methods for the preparation of bulk-scale DNA hydrogels with adjustable mechanical properties. Herein, we introduce a straightforward and efficient molecular design approach to producing physically pure DNA hydrogel and controlling its mechanical properties by adjusting the degree of hydrogen bonding in ultralong single-stranded DNA (ssDNA) precursors, which were generated using a dual rolling circle amplification (RCA)-based strategy. The effect of hydrogen bonding degree on the performance of DNA hydrogels was thoroughly investigated by analyzing the preparation process, morphology, rheology, microstructure, and entrapment efficiency of the hydrogels for Au nanoparticles (AuNPs)–BSA. Our results demonstrate that DNA hydrogels can be formed at 25 °C with simple vortex mixing in less than 10 s. The experimental results also indicate that a higher degree of hydrogen bonding in the precursor DNA resulted in stronger internal interaction forces, a more complex internal network of the hydrogel, a denser hydrogel, improved mechanical properties, and enhanced entrapment efficiency. This study intuitively demonstrates the effect of hydrogen bonding on the preparation and properties of DNA hydrogels. The method and results presented in this study are of great significance for improving the synthesis efficiency and economy of DNA hydrogels, enhancing and adjusting the overall quality and performance of the hydrogel, and expanding the application field of DNA hydrogels.
4
Palungan, Juliana, Widya Luthfiyah, Apon Zaenal Mustopa, Maritsa Nurfatwa, Latifah Rahman, Risfah Yulianty, Nasrul Wathoni, Jin-Wook Yoo, and Nurhasni Hasan. "The Formulation and Characterization of Wound Dressing Releasing S-Nitrosoglutathione from Polyvinyl Alcohol/Borax Reinforced Carboxymethyl Chitosan Self-Healing Hydrogel." Pharmaceutics 16, no. 3 (February 29, 2024): 344. http://dx.doi.org/10.3390/pharmaceutics16030344.
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Self-healing hydrogels often lack mechanical properties, limiting their wound-dressing applications. This study introduced S-Nitrosoglutathione (GSNO) to self-healing hydrogel-based wound dressings. Self-healing hydrogel mechanical properties were improved via polymer blends. Applying this hydrogel to the wound site allows it to self-heal and reattach after mechanical damage. This work evaluated polyvinyl alcohol (PVA)-based self-healing hydrogels with borax as a crosslinking agent and carboxymethyl chitosan as a mechanical property enhancer. Three formulations (F1, F4, and F7) developed self-healing hydrogels. These formulations had borax concentrations of 0.8%, 1.2%, and 1.6%. An FTIR study shows that borate ester crosslinking and hydrogen bonding between polymers generate a self-healing hydrogel. F4 has a highly uniform and regular pore structure, as shown by the scanning electron microscope image. F1 exhibited faster self-healing, taking 13.95 ± 1.45 min compared to other formulations. All preparations had pH values close to neutrality, making them suitable wound dressings. Formula F7 has a high drug content (97.34 ± 1.21%). Good mechanical qualities included high tensile stress–strain intensity and Young’s modulus. After 28 h of storage at −20 °C, 5 °C, and 25 °C, the self-healing hydrogel’s drug content dropped significantly. The Korsmeyer–Peppas release model showed that the release profile of GSNO followed Fickian diffusion. Thus, varying the concentration of crosslinking agent and adding a polymer affects self-healing hydrogels’ physicochemical properties.
5
Dai, Bailin, Ting Cui, Yue Xu, Shaoji Wu, Youwei Li, Wu Wang, Sihua Liu, Jianxin Tang, and Li Tang. "Smart Antifreeze Hydrogels with Abundant Hydrogen Bonding for Conductive Flexible Sensors." Gels 8, no. 6 (June 13, 2022): 374. http://dx.doi.org/10.3390/gels8060374.
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Recently, flexible sensors based on conductive hydrogels have been widely used in human health monitoring, human movement detection and soft robotics due to their excellent flexibility, high water content, good biocompatibility. However, traditional conductive hydrogels tend to freeze and lose their flexibility at low temperature, which greatly limits their application in a low temperature environment. Herein, according to the mechanism that multi−hydrogen bonds can inhibit ice crystal formation by forming hydrogen bonds with water molecules, we used butanediol (BD) and N−hydroxyethyl acrylamide (HEAA) monomer with a multi−hydrogen bond structure to construct LiCl/p(HEAA−co−BD) conductive hydrogel with antifreeze property. The results indicated that the prepared LiCl/p(HEAA−co−BD) conductive hydrogel showed excellent antifreeze property with a low freeze point of −85.6 °C. Therefore, even at −40 °C, the hydrogel can still stretch up to 400% with a tensile stress of ~450 KPa. Moreover, the hydrogel exhibited repeatable adhesion property (~30 KPa), which was attributed to the existence of multiple hydrogen bonds. Furthermore, a simple flexible sensor was fabricated by using LiCl/p(HEAA−co−BD) conductive hydrogel to detect compression and stretching responses. The sensor had excellent sensitivity and could monitor human body movement.
6
Jiang, Zhiqiang, Ya Li, Yirui Shen, Jian Yang, Zongyong Zhang, Yujing You, Zhongda Lv, and Lihui Yao. "Robust Hydrogel Adhesive with Dual Hydrogen Bond Networks." Molecules 26, no. 9 (May 4, 2021): 2688. http://dx.doi.org/10.3390/molecules26092688.
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Hydrogel adhesives are attractive for applications in intelligent soft materials and tissue engineering, but conventional hydrogels usually have poor adhesion. In this study, we designed a strategy to synthesize a novel adhesive with a thin hydrogel adhesive layer integrated on a tough substrate hydrogel. The adhesive layer with positive charges of ammonium groups on the polymer backbones strongly bonds to a wide range of nonporous materials’ surfaces. The substrate layer with a dual hydrogen bond system consists of (i) weak hydrogen bonds between N,N-dimethyl acrylamide (DMAA) and acrylic acid (AAc) units and (ii) strong multiple hydrogen bonds between 2-ureido-4[1H]-pyrimidinone (UPy) units. The dual hydrogen-bond network endowed the hydrogel adhesives with unique mechanical properties, e.g., toughness, highly stretchability, and insensitivity to notches. The hydrogel adhesion to four types of materials like glass, 316L stainless steel, aluminum, Al2O3 ceramic, and two biological tissues including pig skin and pig kidney was investigated. The hydrogel bonds strongly to dry solid surfaces and wet tissue, which is promising for biomedical applications.
7
Juan, Chieh-Yun, You-Sheng Zhang, Jen-Kun Cheng, Yu-Hsu Chen, Hsin-Chieh Lin, and Mei-Yu Yeh. "Lysine-Triggered Polymeric Hydrogels with Self-Adhesion, Stretchability, and Supportive Properties." Polymers 16, no. 10 (May 13, 2024): 1388. http://dx.doi.org/10.3390/polym16101388.
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Hydrogels, recognized for their flexibility and diverse characteristics, are extensively used in medical fields such as wearable sensors and soft robotics. However, many hydrogel sensors derived from biomaterials lack mechanical strength and fatigue resistance, emphasizing the necessity for enhanced formulations. In this work, we utilized acrylamide and polyacrylamide as the primary polymer network, incorporated chemically modified poly(ethylene glycol) (DF-PEG) as a physical crosslinker, and introduced varying amounts of methacrylated lysine (LysMA) to prepare a series of hydrogels. This formulation was labeled as poly(acrylamide)-DF-PEG-LysMA, abbreviated as pADLx, with x denoting the weight/volume percentage of LysMA. We observed that when the hydrogel contained 2.5% w/v LysMA (pADL2.5), compared to hydrogels without LysMA (pADL0), its stress increased by 642 ± 76%, strain increased by 1790 ± 95%, and toughness increased by 2037 ± 320%. Our speculation regarding the enhanced mechanical performance of the pADL2.5 hydrogel revolves around the synergistic effects arising from the co-polymerization of LysMA with acrylamide and the formation of multiple intermolecular hydrogen bonds within the network structures. Moreover, the acid, amine, and amide groups present in the LysMA molecules have proven to be instrumental contributors to the self-adhesion capability of the hydrogel. The validation of the pADL2.5 hydrogel’s exceptional mechanical properties through rigorous tensile tests further underscores its suitability for use in strain sensors. The outstanding stretchability, adhesive strength, and fatigue resistance demonstrated by this hydrogel affirm its potential as a key component in the development of robust and reliable strain sensors that fulfill practical requirements.
8
Fu, Qiang, Junxiao Tang, Weimin Wang, and Rongjie Wang. "Biocomposite Polyvinyl Alcohol/Ferritin Hydrogels with Enhanced Stretchability and Conductivity for Flexible Strain Sensors." Gels 11, no. 1 (January 11, 2025): 59. https://doi.org/10.3390/gels11010059.
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Protein-based hydrogels with stretchability and conductivity have potential applications in wearable electronic devices. However, the development of protein-based biocomposite hydrogels is still limited. In this work, we used natural ferritin to develop a PVA/ferritin biocomposite hydrogel by a repetitive freeze–thaw method. In this biocomposite hydrogel, ferritin, as a nano spring, forms a hydrogen bond with the PVA networks, which reduces the crystallinity of PVA and significantly improves the stretchability of the hydrogel. The fracture strain of the PVA/ferritin hydrogel is 203%, and the fracture stress is 112.2 kPa. The fracture toughness of the PVA/ferritin hydrogel is significantly enhanced to 147.03 kJ/m3, more than 3 times that of the PVA hydrogel (39.17 kJ/m3). In addition, the free residues and iron ions of ferritin endow the biocomposite hydrogel with enhanced ionic conductivity (0.15 S/m). The strain sensor constructed from this hydrogel shows good sensitivity (gauge factor = 1.7 at 150% strain), accurate real-time resistance response, and good long cyclic working stability when used for joint motion monitoring. The results indicate that a PVA/ferritin biocomposite hydrogel prepared by a facile method has enhanced stretchability and conductivity for flexible strain sensors. This work develops a new method for the preparation of protein-based hydrogels for wearable electronic devices.
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Xing, Wenjin, Amin Jamshidi Ghahfarokhi, Chaoming Xie, Sanaz Naghibi, Jonathan A. Campbell, and Youhong Tang. "Mechanical Properties of a Supramolecular Nanocomposite Hydrogel Containing Hydroxyl Groups Enriched Hyper-Branched Polymers." Polymers 13, no. 5 (March 6, 2021): 805. http://dx.doi.org/10.3390/polym13050805.
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Owing to highly tunable topology and functional groups, hyper-branched polymers are a potential candidate for toughening agents, for achieving supramolecular interactions with hydrogel networks. However, their toughening effects and mechanisms are not well understood. Here, by means of tensile and pure shear testings, we characterise the mechanics of a nanoparticle–hydrogel hybrid system that incorporates a hyper-branched polymer (HBP) with abundant hydroxyl end groups into the matrix of the polyacrylic acid (PAA) hydrogel. We found that the third and fourth generations of HBP are more effective than the second one in terms of strengthening and toughening effects. At a HBP content of 14 wt%, compared to that of the pure PAA hydrogel, strengths of the hybrid hydrogels with the third and fourth HBPs are 2.3 and 2.5 times; toughnesses are increased by 525% and 820%. However, for the second generation, strength is little improved, and toughness is increased by 225%. It was found that the stiffness of the hybrid hydrogel is almost unchanged relative to that of the PAA hydrogel, evidencing the weak characteristic of hydrogen bonds in this system. In addition, an outstanding self-healing feature was observed, confirming the fast reforming nature of broken hydrogen bonds. For the hybrid hydrogel, the critical size of failure zone around the crack tip, where serious viscous dissipation occurs, is related to a fractocohesive length, being about 0.62 mm, one order of magnitude less than that of other tough double-network hydrogels. This study can promote the application of hyper-branched polymers in the rapid evolving field of hydrogels for improved performance.
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Rao, Kummara Madhusudana, Kannan Badri Narayanan, Uluvangada Thammaiah Uthappa, Pil-Hoon Park, Inho Choi, and Sung Soo Han. "Tissue Adhesive, Self-Healing, Biocompatible, Hemostasis, and Antibacterial Properties of Fungal-Derived Carboxymethyl Chitosan-Polydopamine Hydrogels." Pharmaceutics 14, no. 5 (May 10, 2022): 1028. http://dx.doi.org/10.3390/pharmaceutics14051028.
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In this work, fungal mushroom-derived carboxymethyl chitosan-polydopamine hydrogels (FCMCS-PDA) with multifunctionality (tissue adhesive, hemostasis, self-healing, and antibacterial properties) were developed for wound dressing applications. The hydrogel is obtained through dynamic Schiff base cross-linking and hydrogen bonds between FCMCS-PDA and covalently cross-linked polyacrylamide (PAM) networks. The FCMCS-PDA-PAM hydrogels have a good swelling ratio, biodegradable properties, excellent mechanical properties, and a highly interconnected porous structure with PDA microfibrils. Interestingly, the PDA microfibrils were formed along with FCMCS fibers in the hydrogel networks, which has a high impact on the biological performance of hydrogels. The maximum adhesion strength of the hydrogel to porcine skin was achieved at about 29.6 ± 2.9 kPa. The hydrogel had good self-healing and recoverable properties. The PDA-containing hydrogels show good antibacterial properties on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria. Moreover, the adhesive hydrogels depicted good viability and attachment of skin fibroblasts and keratinocyte cells. Importantly, FCMCS and PDA combined resulted in fast blood coagulation within 60 s. Hence, the adhesive hydrogel with multifunctionality has excellent potential as a wound dressing material for infected wounds.
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Fan, Jie-Ping, Ming-Ru Xie, Chao Yuan, Jia Ma, Ke-Pu Fu, Chun-Hong Huang, Hui-Ping Chen, Hai-Long Peng, and Chun-Fang Xie. "Fabricating a SFMA/BAChol/PAA/ZnCl2 Hydrogel with Excellent Versatile Comprehensive Properties and Stable Sensitive Freezing-Tolerant Conductivity for Wearable Sensors." International Journal of Molecular Sciences 25, no. 24 (December 12, 2024): 13339. https://doi.org/10.3390/ijms252413339.
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Flexible wearable sensors have obtained tremendous interest in various fields and conductive hydrogels are a promising candidate. Nevertheless, the insufficient mechanical properties, the low electrical conductivity and sensitivity, and the limited functional properties prevent the development of hydrogels as wearable sensors. In this study, an SFMA/BAChol/PAA/ZnCl2 hydrogel was fabricated with high mechanical strength and versatile comprehensive properties. Specifically, the obtained hydrogel displayed excellent adhesion and mechanical stability, cryophylactic ability, stable sensitive freezing-tolerant conductivity, and feasible electrical conduction under a wide temperature range, demonstrating the high application potential as a flexible wearable sensor for movement behavior surveillance, even under harsh environments. Furthermore, the mechanical strength of the hydrogel could easily be regulated by varying the copolymer content. The molecular mechanisms of the hydrogel formation and the reversible adhesion during the wet-dry transition were proposed. The non-covalent interactions, including the electrostatic interaction, hydrogen bond interaction and hydrophobic association, and coordination interaction, were dynamically presented in the hydrogel network and hence supported the versatile comprehensive properties of the hydrogel. This study provides a strategy for designing novel hydrogels to promote the development of flexible sensors with stable sensitive freezing-tolerant conductivity.
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Li, Xin, Hui Gao, Qiang Wang, and Shanshan Liu. "Enhancing the Toughness of PAA/LCNF/SA Hydrogel through Double-Network Crosslinking for Strain Sensor Application." Polymers 16, no. 1 (December 28, 2023): 102. http://dx.doi.org/10.3390/polym16010102.
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Lignin-containing nanocellulose fibers (LCNF) have been considered as a valuable enhancer for polyacrylic acid (PAA)-based hydrogels that can form rigid porous network structures and provide abundant polar groups. However, the PAA–LCNF hydrogel is dominated by a single-network (SN) structure, which shows certain limitations when encountering external environments with high loads and large deformations. In this paper, sodium alginate (SA) was introduced into the PAA–LCNF hydrogel network to prepare a double-network (DN) hydrogel structure of the SA-Ca2+ and PAA–LCNF through a two-step process. The covalent network of PAA–LCNF acts as the resilient framework of the hydrogel, while the calcium bridging networks of SA, along with the robust hydrogen bonding network within the system, function as sacrificial bonds that dissipate energy and facilitate stress transfer. The resulting hydrogel has porous morphologies. Results show that SA can effectively improve the mechanical properties of DN hydrogels and endow them with excellent thermal stability and electrical conductivity. Compared with pure PAA–LCNF hydrogel, the elongation at break of DN hydrogel increased from 3466% to 5607%. The good electrical conductivity makes it possible to use the flexible sensors based on DN hydrogel to measure electrophysiological signals. Our results can provide a reference for developing multifunctional hydrogels that can withstand ultra large deformation.
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Zhang, Ran, Wenhui Zhao, Fangdong Ning, Jinming Zhen, Huifen Qiang, Yujue Zhang, Fengzhen Liu, and Zhengfeng Jia. "Alginate Fiber-Enhanced Poly(vinyl alcohol) Hydrogels with Superior Lubricating Property and Biocompatibility." Polymers 14, no. 19 (September 28, 2022): 4063. http://dx.doi.org/10.3390/polym14194063.
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The design of a novel interpenetrating network hydrogel inspired by the microscopic architecture of natural cartilage based on a supramolecular sodium alginate (SA) nanofibril network is reported in this paper. The mechanical strength and toughness of the poly (vinyl alcohol) (PVA) hydrogel were significantly improved after being incorporated with the alginate nanofibril network. The multiple hydrogen bonds between PVA chains and alginate fibers provided an efficient energy dissipation, thus leading to a significant increase in the mechanical strength of the PVA/SA/NaCl hydrogel. The PVA/SA/NaCl hydrogel demonstrated superior water-lubrication and load-bearing performance due to noncovalent interactions compared with pure PVA hydrogels. Moreover, the bioactivity of the PVA/SA/NaCl hydrogel was proved by the MC3T3 cell proliferation and viability assays over 7 days. Therefore, alginate fiber-enhanced hydrogels with high strength and low friction properties are expected to be used as novel biomimetic lubrication materials.
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Zhang, Yulin, Shiyu Wang, Yi Tian, Long Chen, Yuhan Du, Gehong Su, and Yu Hu. "Multi-Physically Cross-Linked Hydrogels for Flexible Sensors with High Strength and Self-Healing Properties." Polymers 15, no. 18 (September 13, 2023): 3748. http://dx.doi.org/10.3390/polym15183748.
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Excellent mechanical properties and self-healing properties are very important for the practical application of hydrogel flexible sensors. In this study, acrylic acid and stearyl methyl acrylate were selected as monomers to synthesize hydrophobic association hydrogels, and multi-physically cross-linked hydrogels were synthesized by adding ferric chloride and polyvinyl alcohol to introduce ion interaction and a hydrogen bond cross-linking network. The hydrogels were characterized by FTIR, XRD and SEM, and the mechanical properties and self-healing properties were tested using a universal testing machine. It was confirmed that the strength of the hydrogel was significantly improved with the addition of ferric chloride and polyvinyl alcohol, and the hydrogel still showed good self-healing properties. Further testing of its application as a conductive sensor has demonstrated sensitive and stable motion sensing capabilities. This provides an important reference for high-performance hydrogel sensors with both high strength and self-healing properties.
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Ji, Feng, Pengbo Shang, Yingkai Lai, Jinmei Wang, Guangcai Zhang, Dengchao Lin, Jing Xu, Daniu Cai, and Zhihui Qin. "Fully Physically Crosslinked Conductive Hydrogel with Ultrastretchability, Transparency, and Self-Healing Properties for Strain Sensors." Materials 16, no. 19 (September 29, 2023): 6491. http://dx.doi.org/10.3390/ma16196491.
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Currently, conductive hydrogels have received great attention as flexible strain sensors. However, the preparation of such sensors with integrated stretchability, transparency, and self-healing properties into one gel through a simple method still remains a huge challenge. Here, a fully physically crosslinked double network hydrogel was developed based on poly(hydroxyethyl acrylamide) (PHEAA) and κ-carrageenan (Car). The driving forces for physical gelation were hydrogen bonds, ion bonding, and electrostatic interactions. The resultant PHEAA-Car hydrogel displayed stretchability (1145%) and optical transparency (92%). Meanwhile, the PHEAA-Car hydrogel exhibited a self-healing property at 25 °C. Additionally, the PHEAA-Car hydrogel-based strain sensor could monitor different joint movements. Based on the above functions, the PHEAA-Car hydrogel can be applied in flexible strain sensors.
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Tang, Yuanhan, Junjie Ding, Xun Zhou, Xintao Ma, Yi Zhao, Qiyu Mu, Zixu Huang, Qian Tao, Fangjie Liu, and Ling Wang. "Injectable hydrogels of enzyme-catalyzed cross-linked tyramine-modified gelatin for drug delivery." Australian Journal of Chemistry 76, no. 2 (February 28, 2023): 88–99. http://dx.doi.org/10.1071/ch22188.
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Enzymatically catalyzed cross-linking is a hydrogel fabrication method that generally is considered to have lower cytotoxicity than traditional chemical cross-linking methods. In order to optimize the properties of injectable hydrogels and expand their applications, an enzyme-catalyzed cross-linked injectable hydrogel was designed. The tyramine-modified gelatin (G-T) was formed into a stable injectable hydrogel by the combination of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) catalysis. 1H NMR spectroscopy was used to demonstrate the successful modification of gelatin by tyramine. The surface morphology of the prepared hydrogels was characterized jointly by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Rheological tests demonstrated the tunable mechanical strength, formation kinetics, shear thinning and good self-recovery properties of the hydrogels. In addition, the hydrogels can be formed into various shapes by injection. The hydrogel network structure is complex and interlaced, as such it is suitable to encapsulate drugs for controlled release. The drug release from the prepared hydrogels followed the Peppas–Sahlin model and belonged to Fickian diffusion. This study constructed injectable hydrogels through the enzyme-catalyzed cross-linking of modified gelatin and applied the hydrogels for drug release, which is expected to expand the application in biomedical fields.
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Lan, Yu-Ting, Qian-Pu Cheng, Junpeng Xu, Shih-Ho Lin, Jhih-Min Lin, and Shan-hui Hsu. "Gelation and the Self-Healing Behavior of the Chitosan–Catechol Hydrogel." Polymers 14, no. 21 (October 30, 2022): 4614. http://dx.doi.org/10.3390/polym14214614.
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Mussel-inspired adhesive hydrogels have been developed in biomedical fields due to their strong adhesive property, cohesive capability, biocompatibility, and hemostatic ability. Catechol-functionalized chitosan is a potential polymer used to prepare adhesive hydrogels. However, the unique gelation mechanism and self-healing properties of catechol-grafted chitosan alone have not yet been explored. Herein, catechol-grafted chitosan (CC) was synthesized and further concentrated to obtain the self-healing CC hydrogels. The gelation mechanism of CC hydrogels may be attributed to the formation of hydrogen bonding, cation–π interactions, Michael addition, or Schiff base reactions during concentration phases. Rheological studies showed that the CC hydrogel owned self-healing properties in repeated damage–healing cycles. Coherent small-angle X-ray scattering (SAXS) analyses revealed the formation of a mesoscale structure (~9 nm) as the solid content of the hydrogel increased. In situ SAXS combined with rheometry verified the strain-dependent behavior of the CC hydrogel. The CC hydrogel displayed the osmotic-responsive behavior and enhanced adhesive strength (0.38 N/cm2) after immersion in the physiological saline. The CC scaffold prepared by lyophilizing the CC hydrogel revealed a macroporous structure (~200 µm), a high swelling ratio (9656%), good compressibility, and durability. This work provides an insight into the design of using chitosan–catechol alone to produce hydrogels or scaffolds with tunable mechanical properties for further applications in biomedical fields.
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Adjuik, Toby A., Sue E. Nokes, Michael Montross, Ole Wendroth, and Riley Walton. "Alkali Lignin-Based Hydrogel: Synthesis, Characterization, and Impact on Soil Water Retention From Near Saturation to Dryness." Journal of the ASABE 66, no. 1 (2023): 85–98. http://dx.doi.org/10.13031/ja.15207.
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Highlights A lignin-based hydrogel was synthesized and shown to possess a swelling ratio of 2013%. The hydrogel contained important hydrophilic hydroxyl groups and macropores for water retention. The hydrogel improved soil water retention in silt loam soil at high matric potentials and in the dry soil range. Increasing hydrogel concentration increased water retention in a loamy fine sand soil at high and low matric potentials. Abstract. Superabsorbent polymers (hydrogels) have been proposed as soil amendments to increase the amount of plant-available water in the soil. Synthetic hydrogels have been widely investigated for use in agriculture. Due to increasing environmental concerns related to synthetic hydrogels, naturally sourced hydrogels are of interest because of their potential for increased biodegradability and biocompatibility. A lignin-based hydrogel was synthesized for this study, and its swelling properties and water absorption capacity were determined. The hydrogel was characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and gas pycnometry. A hanging water column, pressure plate apparatus, and dew point potentiometer were used to measure the soil water retention curve from saturation to oven-dryness for silt loam and loamy fine sand soils after amendment with the lignin-based hydrogel. Results showed a maximum swelling ratio in deionized water of 2013% of the hydrogel’s original mass, 1092% in tap water, and 825% in a 0.9% NaCl solution. The FTIR spectra of the hydrogel showed the presence of O-H bonds from the lignin structure, which renders the hydrogel reactive to a crosslinker and forms insoluble bonds, thereby allowing the hydrogel to swell when exposed to water. SEM images of the lignin hydrogels indicate large macropores, which allowed for water absorption. Applying hydrogels significantly increased the soil's water-holding capacity at 0.3% (w/w) treatment. Hydrogel treatment significantly increased water retention at saturation or near saturation by 0.12 cm3 cm-3 and at field capacity by 0.08 cm3 cm-3 for silt loam soil at 1% (w/w) treatment compared to the control treatment with no added lignin hydrogel. Hydrogel application increased water retention over the range of the soil water retention curve from -3 to -15,000 cm for the loamy fine sand soil at 1% (w/w) treatment. However, the application of lignin-based hydrogel did not affect plant available water capacity (PAWC) in either soil tested. These results serve as preliminary evidence upon which further lignin-based hydrogel amendment studies could be built by testing higher concentrations of hydrogel in the soil. Keywords: Lignin, Soil water retention curve, Super absorbent polymers, Swelling capacity, Water retention.
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Wu, Hongyi, Nitong Bu, Jie Chen, Yuanyuan Chen, Runzhi Sun, Chunhua Wu, and Jie Pang. "Construction of Konjac Glucomannan/Oxidized Hyaluronic Acid Hydrogels for Controlled Drug Release." Polymers 14, no. 5 (February 25, 2022): 927. http://dx.doi.org/10.3390/polym14050927.
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Konjac glucomannan (KGM) hydrogel has favorable gel-forming abilities, but its insufficient swelling capacity and poor control release characteristics limit its application. Therefore, in this study, oxidized hyaluronic acid (OHA) was used to improve the properties of KGM hydrogel. The influence of OHA on the structure and properties of KGM hydrogels was evaluated. The results show that the swelling capacity and rheological properties of the composite hydrogels increased with OHA concentration, which might be attributed to the hydrogen bond between the KGM and OHA, resulting in a compact three-dimensional gel network structure. Furthermore, epigallocatechin gallate (EGCG) was efficiently loaded into the KGM/OHA composite hydrogels and liberated in a sustained pattern. The cumulative EGCG release rate of the KGM/OHA hydrogels was enhanced by the increasing addition of OHA. The results show that the release rate of composite hydrogel can be controlled by the content of OHA. These results suggest that OHA has the potential to improve the properties and control release characteristics of KGM hydrogels.
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Zitouni, Mohammed Amine, and Sofia Borsali Kara Slimane. "Preparation and Characterization of Hydrogels Based on Chitsoan/Polyvinyl Alcohol Blends." Advanced Materials Research 1105 (May 2015): 203–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1105.203.
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In this study, a series of poly (vinyl alcohol) (PVA)/chitosan (CS) hydrogels with different weight ratio of PVA to CS were prepared by freezing-thawing (F-T) method. The structure, morphology, and crystallinity of hydrogels were investigated by Fourier Transform Infrared (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). FTIR demonstrated the presence of strong intermolecular hydrogen bonds between CS and PVA molecules. SEM images showed that the higher the chitosan, the greater the porous size of the hydrogel and DSC confirmed that crystallinity is higher when PVA is more in hydrogel. The mechanical properties of these hydrogels were studied by rheometry. The study of swelling ability demonstrated that the hydrogel developed with PVA and Cs was more swellable than that with PVA only because of its cross-linking interaction with PVA.
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Agusnar, Harry. "Comparison Study of Fabrication and Characterization of Bead Chitosan Hydrogel and Yarn Chitosan Hydrogel From High Molecular Chitosan." Journal of Chemical Natural Resources 2, no. 2 (August 19, 2022): 150–55. http://dx.doi.org/10.32734/jcnar.v2i2.9328.
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The research about comparison study of fabrication and characterization of bead chitosan hydrogel and yarn chitosan hydrogel from high molecular chitosan has been successfully conducted. High molecular chitosan was dissolved into 100 ml of 1, 1.5, and 2% of acetic acid and stirred until the chitosan was dissolved completely. The formed chitosan solution was then taken as much as 6 mL using a syringe and dropped slowly to form small beads into a Petri dish containing NaOH 0.3 M then string into a Petri dish containing acetone 1% and dried at ±50ºC. The bead chitosan hydrogel and yarn chitosan hydrogen results were characterized in which differences of functional groups on chitosan with beads chitosan hydrogel and yarn chitosan hydrogel that occurred in the highest spectra peaks was the band at 3433.29 cm-1, which indicated NH groups on chitosan had changed into an O-H group (3653.18 cm-1) on the bead chitosan hydrogels 1% and yarn chitosan hydrogel 1% which showed the existence of chemical interactions. The yarn chitosan hydrogel has better absorption capability compared to bead chitosan hydrogel. Due to the surface area of the chitosan yarn hydrogel being wider than the beads' chitosan hydrogel.
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Vera Nanda, E., Y. Yusmaniar, R. Juniar, and Y. Pratiwi. "Utilizing Nata de Pina for Hydrogel Synthesis: Effects of Citric Acid on Hydrogel Characteristics." Journal of Physics: Conference Series 2866, no. 1 (October 1, 2024): 012058. http://dx.doi.org/10.1088/1742-6596/2866/1/012058.
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Abstract The increasing production of pineapples will produce waste that’s increasing anyway. To optimize the utilization of pineapple skin waste One solution is to use the pineapple skin waste To be used as the main material for making nata de pina. Nata de pina is fiber cellulose on the surface of pineapple medium from the results of Acetobacter xylinum bacterial metabolism. The resulting cellulose is then used as a basic material manufacture of natural polimer as hydrogel. The research stage consists of 3 stages, namely making Nata de Pina, the manufacture of hydrogels as well as the characterization of the resulting hydrogels. The method used in hydrogel synthesis is chemical crosslinking with citric acid as a crosslinking agent. Variable variations performed in This study is the use of citric acid concentrations of 35%,37,5%,40%, and 42.5%. Nata de Pina-based hydrogel was successfully synthesized. Hydrogels based on Nata de Pina were successfully synthesized. It is shown based on the results of the FTIR test that the hydrogel has a C=O group that proving that there has been a cross-linking between cellulose and citric acid. The resulting hydrogel has good antibacterial activity against bacteria-positive and negative grams. The best results are shown by hydrogels with 40% concentration where the hydrogel has a maximum tensile strength value by 11.4 MPa. This study aim the innovative use of Nata de Pina, a byproduct of pineapple peel waste, as a novel material for hydrogel synthesis. By employing citric acid as a crosslinking agent, we investigated the effects on the hydrogel’s mechanical and swelling properties. Our findings demonstrate the potential of Nata de Pina-based hydrogels in sustainable material applications, offering an eco-friendly alternative to synthetic polymers.
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Wei, Shih-Yen, Tzu-Hsuan Chen, Feng-Sheng Kao, Yi-Jung Hsu, and Ying-Chieh Chen. "Strategy for improving cell-mediated vascularized soft tissue formation in a hydrogen peroxide-triggered chemically-crosslinked hydrogel." Journal of Tissue Engineering 13 (January 2022): 204173142210840. http://dx.doi.org/10.1177/20417314221084096.
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The physically-crosslinked collagen hydrogels can provide suitable microenvironments for cell-based functional vascular network formation due to their biodegradability, biocompatibility, and good diffusion properties. However, encapsulation of cells into collagen hydrogels results in extensive contraction and rapid degradation of hydrogels, an effect known from their utilization as a pre-vascularized graft in vivo. Various types of chemically-crosslinked collagen-based hydrogels have been successfully synthesized to decrease volume contraction, retard the degradation rate, and increase mechanical tunability. However, these hydrogels failed to form vascularized tissues with uniformly distributed microvessels in vivo. Here, the enzymatically chemically-crosslinked collagen-Phenolic hydrogel was used as a model to determine and overcome the difficulties in engineering vascular networks. Results showed that a longer duration of inflammation and excessive levels of hydrogen peroxide limited the capability for blood vessel forming cells-mediated vasculature formation in vivo. Lowering the unreacted amount of crosslinkers reduced the densities of infiltrating host myeloid cells by half on days 2–4 after implantation, but blood vessels remained at low density and were mainly located on the edge of the implanted constructs. Co-implantation of a designed spacer with cell-laden hydrogel maintained the structural integrity of the hydrogel and increased the degree of hypoxia in embedded cells. These effects resulted in a two-fold increase in the density of perfused blood vessels in the hydrogel. Results agreed with computer-based simulations. Collectively, our findings suggest that simultaneous reduction of the crosslinker-induced host immune response and increase in hypoxia in hydrogen peroxide-triggered chemically-crosslinked hydrogels can effectively improve the formation of cell-mediated functional vascular networks.
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Santos, Francisco, Carolina Marto-Costa, Ana Catarina Branco, Andreia Sofia Oliveira, Rui Galhano dos Santos, Madalena Salema-Oom, Roberto Leonardo Diaz, et al. "Tribomechanical Properties of PVA/Nomex® Composite Hydrogels for Articular Cartilage Repair." Gels 10, no. 8 (August 3, 2024): 514. http://dx.doi.org/10.3390/gels10080514.
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Due to the increasing prevalence of articular cartilage diseases and limitations faced by current therapeutic methodologies, there is an unmet need for new materials to replace damaged cartilage. In this work, poly(vinyl alcohol) (PVA) hydrogels were reinforced with different amounts of Nomex® (known for its high mechanical toughness, flexibility, and resilience) and sterilized by gamma irradiation. Samples were studied concerning morphology, chemical structure, thermal behavior, water content, wettability, mechanical properties, and rheological and tribological behavior. Overall, it was found that the incorporation of aramid nanostructures improved the hydrogel’s mechanical performance, likely due to the reinforcement’s intrinsic strength and hydrogen bonding to PVA chains. Additionally, the sterilization of the materials also led to superior mechanical properties, possibly related to the increased crosslinking density through the hydrogen bonding caused by the irradiation. The water content, wettability, and tribological performance of PVA hydrogels were not compromised by either the reinforcement or the sterilization process. The best-performing composite, containing 1.5% wt. of Nomex®, did not induce cytotoxicity in human chondrocytes. Plugs of this hydrogel were inserted in porcine femoral heads and tested in an anatomical hip simulator. No significant changes were observed in the hydrogel or cartilage, demonstrating the material’s potential to be used in cartilage replacement.
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Duan, Bingchao, Minghui Yang, Quanchao Chao, Lan Wang, Lingli Zhang, Mengxing Gou, Yuling Li, Congjun Liu, and Kui Lu. "Preparation and Properties of Egg White Dual Cross-Linked Hydrogel with Potential Application for Bone Tissue Engineering." Polymers 14, no. 23 (November 24, 2022): 5116. http://dx.doi.org/10.3390/polym14235116.
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In this study, an egg white dual cross-linked hydrogel was developed based on the principle that the external stimulus can denature proteins and cause them to aggregate, forming hydrogel. The sodium hydroxide was used to induce gelation of the egg white protein, subsequently introducing calcium ions to cross-link with protein chains, thereby producing a dual cross-linked hydrogel. The characteristics of the dual cross-linked hydrogels—including the secondary structure, stability, microstructure, swelling performance, texture properties, and biosafety—were investigated to determine the effects of calcium ion on the egg white hydrogel (EWG) and evaluate the potential application in the field of tissue engineering. Results showed that calcium ions could change the β-sheet content of the protein in EWG after soaking it in different concentrations of CaCl2 solution, leading to changes in the hydrogen bonds and the secondary structure of polypeptide chains. It was confirmed that calcium ions promoted the secondary cross-linking of the protein chain, which facilitated polypeptide folding and aggregation, resulting in enhanced stability of the egg white dual cross-linked hydrogel. Furthermore, the swelling capacity of the EWG decreased with increasing concentration of calcium ions, and the texture properties including hardness, cohesiveness and springiness of the hydrogels were improved. In addition, the calcium cross-linked EWG hydrogels exhibited biocompatibility and cell-surface adhesion in vitro. Hence, this work develops a versatile strategy to fabricate dual cross-linked protein hydrogel with biosafety and cell-surface adhesion, and both the strategy and calcium-egg white cross-linked hydrogels have potential for use in bone tissue engineering.
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Sihombing, Y. A., N. Nafisah, I. Anshori, D. A. Hapidin, D. Edikresnha, and K. Khairurrijal. "Preparation and Characterization of PVA/Chitosan-Based Hydrogels Enriched with Carbon Materials via the Freeze-Thaw Method." Journal of Physics: Conference Series 2733, no. 1 (March 1, 2024): 012011. http://dx.doi.org/10.1088/1742-6596/2733/1/012011.
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Abstract The freeze-thaw method successfully prepared polyvinyl alcohol (PVA)/chitosan (CS)-based hydrogels. This study evaluated the hydrogel’s physical and thermal properties with a compositional variation of activated carbon (AC) and reduced graphene oxide (rGO) in PVA/CS (PCS) hydrogel. Incorporating AC into the PCS hydrogel led to pore reduction, yielding a lower swelling degree in PCS/AC hydrogel than in PCS hydrogel. On the other hand, adding rGO had minimal impact on the shape and distribution of pores. However, rGO exhibited effective dispersion on the hydrogel surface, reducing the swelling degree of PCS/rGO hydrogel. The maximum swelling degree only showed an increase in PCS/AC 0.1%, attributed to the porous nature of AC, effectively binding water molecules while maintaining a relatively consistent pore size compared to PCS hydrogel. Incorporating AC and rGO into the PCS hydrogel enhanced thermal stability, which is evident from the increased residue and endothermic peak temperature compared to the hydrogel without AC and rGO. These findings suggest that the modification with AC and rGO can enhance the physical and thermal properties of PCS hydrogel.
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Skopinska-Wisniewska, Joanna, Silvia De la Flor, and Justyna Kozlowska. "From Supramolecular Hydrogels to Multifunctional Carriers for Biologically Active Substances." International Journal of Molecular Sciences 22, no. 14 (July 9, 2021): 7402. http://dx.doi.org/10.3390/ijms22147402.
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Supramolecular hydrogels are 3D, elastic, water-swelled materials that are held together by reversible, non-covalent interactions, such as hydrogen bonds, hydrophobic, ionic, host–guest interactions, and metal–ligand coordination. These interactions determine the hydrogels’ unique properties: mechanical strength; stretchability; injectability; ability to self-heal; shear-thinning; and sensitivity to stimuli, e.g., pH, temperature, the presence of ions, and other chemical substances. For this reason, supramolecular hydrogels have attracted considerable attention as carriers for active substance delivery systems. In this paper, we focused on the various types of non-covalent interactions. The hydrogen bonds, hydrophobic, ionic, coordination, and host–guest interactions between hydrogel components have been described. We also provided an overview of the recent studies on supramolecular hydrogel applications, such as cancer therapy, anti-inflammatory gels, antimicrobial activity, controlled gene drug delivery, and tissue engineering.
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Gan, Jing, Lirong Sun, Chenxia Guan, Teng Ren, Qinling Zhang, Shihui Pan, Qian Zhang, and Hao Chen. "Preparation and Properties of Salecan–Soy Protein Isolate Composite Hydrogel Induced by Thermal Treatment and Transglutaminase." International Journal of Molecular Sciences 23, no. 16 (August 20, 2022): 9383. http://dx.doi.org/10.3390/ijms23169383.
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Salecan (Sal) is a novel marine microbial polysaccharide. In the present research, Sal and soy protein isolate (SPI) were adopted to fabricate Sal–SPI composite hydrogel based on a stepwise process (thermal treatment and transglutaminase induction). The effect of Sal concentration on morphology, texture properties, and the microstructure of the hydrogel was evaluated. As Sal concentration varied from 0.4 to 0.6 wt%, hydrogel elasticity increased from 0.49 to 0.85 mm. Furthermore, the internal network structure of Sal–SPI composite hydrogel also became denser and more uniform as Sal concentration increased. Rheological studies showed that Sal–SPI elastic hydrogel formed under the gelation process. Additionally, FTIR and XRD results demonstrated that hydrogen bonds formed between Sal and SPI molecules, inferring the formation of the interpenetrating network structure. This research supplied a green and simple method to fabricate Sal–SPI double network hydrogels.
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Wu, Qingrong, Yu Fu, Wanying Yang, and Shouxin Liu. "A Temperature/pH Double-Responsive and Physical Double-Crosslinked Hydrogel Based on PLA and Histidine." Gels 8, no. 9 (September 7, 2022): 570. http://dx.doi.org/10.3390/gels8090570.
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Hydrogel is a good drug carrier, widely used in the sustained-release aspect of tumor drugs, which can achieve the continuous release of drugs to the tumor sites. In this study, diethylene glycol monomethyl ether methacrylate (MEO2MA) and poly (ethylene glycol) methyl ether methacrylate (OEGMA) are temperature-sensitive monomers. N-Methacryloyl-L-Histidine (Mist) is pH sensitive monomer and ligand for metal coordination bond. The temperature-sensitive monomers and pH sensitive monomer with stereocomplex of modified polylactic acid (HEMA-PLLA30/PDLA30) were mixed, under 2,2’-azobis (2-methylpropionitrile) (AIBN) as radical initiator, polymer was formed by free-radical polymerization. The polymer was then immersed in ZnSO4 solution, the imidazole group of Mist monomer forms a tridentate metal coordination bond with Zn2+, temperature/pH double-responsive and physical double-crosslinked hydrogel was finally obtained. Comparing the hydrogen bond hydrogel, hydrogen bond and metal coordination bond double crosslinking hydrogel, metal coordination bond hydrogel, testing thermal stability, viscoelasticity, swelling, and morphology of three hydrogels. In addition, using UV-Visible spectroscopy (UV-Vis) to test the sustained release of the hydrophobic drug doxorubicin hydrochloride (DOX-HCl) in the human tumor environment (37 °C, pH = 5). We found that the temperature/pH double-responsive and physical double-crosslinked hydrogel had the most potential for the sustained drug release.
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Bibire, Tudor, Radu Dănilă, Cătălina Natalia Yilmaz, Liliana Verestiuc, Isabella Nacu, Ramona Gabriela Ursu, and Cristina Mihaela Ghiciuc. "In Vitro Biological Evaluation of an Alginate-Based Hydrogel Loaded with Rifampicin for Wound Care." Pharmaceuticals 17, no. 7 (July 14, 2024): 943. http://dx.doi.org/10.3390/ph17070943.
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We report a biocompatible hydrogel dressing based on sodium alginate-grafted poly(N-vinylcaprolactam) prepared by encapsulation of Rifampicin as an antimicrobial drug and stabilizing the matrix through the repeated freeze–thawing method. The hydrogel structure and polymer-drug compatibility were confirmed by FTIR, and a series of hydrogen-bond-based interactions between alginate and Rifampicin were identified. A concentration of 0.69% Rifampicin was found in the polymeric matrix using HPLC analysis and spectrophotometric UV–Vis methods. The hydrogel’s morphology was evaluated by scanning electron microscopy, and various sizes and shapes of pores, ranging from almost spherical geometries to irregular ones, with a smooth surface of the pore walls and high interconnectivity in the presence of the drug, were identified. The hydrogels are bioadhesive, and the adhesion strength increased after Rifampicin was encapsulated into the polymeric matrix, which suggests that these compositions are suitable for wound dressings. Antimicrobial activity against S. aureus and MRSA, with an increased effect in the presence of the drug, was also found in the newly prepared hydrogels. In vitro biological evaluation demonstrated the cytocompatibility of the hydrogels and their ability to stimulate cell multiplication and mutual cell communication. The in vitro scratch assay demonstrated the drug-loaded alginate-grafted poly(N-vinylcaprolactam) hydrogel’s ability to stimulate cell migration and wound closure. All of these results suggest that the prepared hydrogels can be used as antimicrobial materials for wound healing and care applications.
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Jiang, Yuchen, Guihua Li, Chenyu Yang, Fangong Kong, and Zaiwu Yuan. "Multiresponsive Cellulose Nanocrystal Cross-Linked Copolymer Hydrogels for the Controlled Release of Dyes and Drugs." Polymers 13, no. 8 (April 9, 2021): 1219. http://dx.doi.org/10.3390/polym13081219.
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Multiresponsive hydrogels have attracted tremendous interest due to their promising applications in tissue engineering, wearable devices, and flexible electronics. In this work, we report a multiresponsive upper critical solution temperature (UCST) composite hydrogel based on poly (acrylic acid-co-acrylamide), PAAc-co-PAAm, sequentially cross-linked by acid-hydrolysis cellulose nanocrystals (CNCs). Scanning electron microscopy (SEM) observations demonstrated that the hydrogels are formed by densely cross-linked porous structures. The PAAc/PAAm/CNC hybrid hydrogels exhibit swelling and shrinking properties that can be induced by multiple stimuli, including temperature, pH, and salt concentration. The driving force of the volume transition is the formation and dissociation of hydrogen bonds in the hydrogels. A certain content of CNCs can greatly enhance the shrinkage capability and mechanical strength of the hybrid hydrogels, but an excess addition may impair the contractility of the hydrogel. Furthermore, the hydrogels can be used as a matrix to adsorb dyes, such as methylene blue (MB), for water purification. MB may be partly discharged from hydrogels by saline solutions, especially by those with high ionic strength. Notably, through temperature-controlled hydrogel swelling and shrinking, doxorubicin hydrochloride (DOX-HCl) can be controllably adsorbed and released from the prepared hydrogels.
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., Arushi, and Ruchi Bharti. "Hydrogel." International Journal for Research in Applied Science and Engineering Technology 11, no. 4 (April 30, 2023): 2312–17. http://dx.doi.org/10.22214/ijraset.2023.50627.
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Abstract: The hydrogel is a tri-polymer network that may soak up body fluids in a biological setting but is not soluble in water. Water can cause the hydrogel to structurally bulge and it can hold a lot of water. Such a polymer network is produced by operating a merging of physical and chemical crosslinking techniques, besides ionic crosslinking, temperature- and optical polymerization, pH-dependent processes, and enzymatic reactions.[1] Physical hydrogels are generally supported by modest secondary forces, whereas covalent forces drive chemical hydrogels. Hydrogel is usually built from an assortment of polymers, both natural and manufactured. The extremely crucial traits of hydrogels are mechanical properties, swelling, and biological characteristics, and every one of them can influence the shape and structure of the hydrogel. Moreover, the structures, classification, advantages, and disadvantages of hydrogel kinds are covered.
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Peng, Yi-Yang, Qiuli Cheng, Meng Wu, Wenda Wang, Jianyang Zhao, Diana Diaz-Dussan, Michelle McKay, Hongbo Zeng, Sarute Ummartyotin, and Ravin Narain. "Highly Stretchable, Self-Healing, Injectable and pH Responsive Hydrogel from Multiple Hydrogen Bonding and Boron-Carbohydrate Interactions." Gels 9, no. 9 (September 1, 2023): 709. http://dx.doi.org/10.3390/gels9090709.
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A simple and cost-effective method for the fabrication of a safe, dual-responsive, highly stretchable, self-healing and injectable hydrogel is reported based on a combination of dynamic boronate ester bonds and hydrogen bonding interactions. The mechanical properties of the hydrogel are tunable by adjusting the molar ratios between sugar moieties on the polymer and borax. It was remarkable to note that the 2:1 ratio of sugar and borate ion significantly improves the mechanical strength of the hydrogel. The injectability, self-healing and stretchability properties of the hydrogel were also examined. In addition, the impact of the variation of the pH and the addition of free sugar responsiveness of the hydrogel was studied. High MRC-5 cell viability was noticed by the 3D live/dead assay after 24 h cell culture within the hydrogel scaffold. Hence, the developed hydrogels have desirable features that warrant their applications for drug delivery, scaffolds for cell and tissue engineering.
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Zhang, Rui, Hongwei Peng, Tianxu Zhou, Min Li, Xuhong Guo, and Yuan Yao. "Selective Adsorption and Separation of Organic Dyes by Poly(acrylic acid) Hydrogels Formed with Spherical Polymer Brushes and Chitosan." Australian Journal of Chemistry 71, no. 11 (2018): 846. http://dx.doi.org/10.1071/ch18228.
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Direct discharge of industry organic dyes has caused serious environmental pollution. In this study, a series of double network poly(acrylic acid) (PAA) hydrogels were fabricated with spherical polymer brushes (SPBs) and chitosan (CS) as crosslinker. Neutral spherical polyelectrolyte brushes of polystyrene–poly-N-isopropylacrylamide (PNIPAM@PS) in which poly(N-isopropylacrylamide) (PNIPAM) arms were grafted on polystyrene (PS) nanospheres, were employed as macro-crosslinkers. The innumerable hydrogen bonds both between the highly entangled PAA chains and between PNIPAM and the PAA chains composed the first network of the hydrogels. The electrostatic interactions between CS and the PAA chains formed the second network of the hydrogels. These double network hydrogels, named PNIPAM@PS/CS/PAA, achieve good compressive performance and a low swell ratio because of their compact structure through plentiful hydrogen bonding and electrostatic interactions. The hydrogel could absorb cationic dyes from water with high separation efficiency and selectivity due to the electrostatic interaction between the carboxy groups and dye molecules. The adsorption process fitted a pseudo-second-order kinetic model and Langmuir isotherm model very well. Moreover, the hydrogel can separate cationic dyes from mixed dye solutions through electrostatic interactions. After being loaded with silver nanoparticles, the obtained silver@hydrogel exhibited a good capacity for the photocatalytic degradation towards different dyes. The hydrogels are promising for dye-containing wastewater treatment.
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Wang, Yangyang, and Yansong Wang. "A Composited Povidone-Iodine Silk Fibroin Hydrogel for Wound Infection." Journal of Biomaterials and Tissue Engineering 9, no. 6 (June 1, 2019): 719–30. http://dx.doi.org/10.1166/jbt.2019.2055.
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Wound infections have historically been an important global health concern which seriously affects human life and health. Reducing the number of bacteria at the site of the wound is essential to prevent wound infection and promote wound healing. Povidone-iodine (PVP-I) is widely used as an antiseptic providing useful properties for local anti-infective treatment in skin, mucous membranes, and wounds. In this study, we synthesized a new PVP-I/silk fibroin (SF) hydrogel through a simple preparation method, and to study the physicochemical properties, antibacterial properties and biocompatibility of the composited hydrogel. Compared with the pure SF hydrogel, the composition of PVP-I with SF hydrogels endowed the hydrogel new physicochemical characteristics especially enhanced hydrogel's structural stability and a sustained-release effect of iodine. Moreover, such composited hydrogels showed better antibacterial properties when the content of the compound PVP-I reached a certain degree. In vivo, the results indicate that the composited hydrogel displayed a good histocompatibility and biodegradability. All these results demonstrated that the composited povidone-iodine silk hydrogel can be fabricated as an anti-infective biomaterials with great potential using in wound infection.
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Jiang, Yuheng, Ying Wang, Qin Li, Chen Yu, and Wanli Chu. "Natural Polymer-based Stimuli-responsive Hydrogels." Current Medicinal Chemistry 27, no. 16 (June 4, 2020): 2631–57. http://dx.doi.org/10.2174/0929867326666191122144916.
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The abilities of intelligent polymer hydrogels to change their structure and volume phase in response to external stimuli have provided new possibilities for various advanced technologies and great research and application potentials in the medical field. The natural polymer-based hydrogels have the advantages of environment-friendliness, rich sources and good biocompatibility. Based on their responsiveness to external stimuli, the natural polymer-based hydrogels can be classified into the temperature-responsive hydrogel, pH-responsive hydrogel, light-responsive hydrogel, electricresponsive hydrogel, redox-responsive hydrogel, enzyme-responsive hydrogel, magnetic-responsive hydrogel, multi-responsive hydrogel, etc. In this review, we have compiled some recent studies on natural polymer-based stimuli-responsive hydrogels, especially the hydrogels prepared from polysaccharides. The preparation methods, properties and applications of these hydrogels in the medical field are highlighted.
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Chen, Kai, Wenzhong Lai, Wangchuan Xiao, Lumin Li, Shijun Huang, and Xiufeng Xiao. "Low-Temperature Adaptive Dual-Network MXene Nanocomposite Hydrogel as Flexible Wearable Strain Sensors." Micromachines 14, no. 8 (August 6, 2023): 1563. http://dx.doi.org/10.3390/mi14081563.
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Flexible electronic devices and conductive materials can be used as wearable sensors to detect human motions. However, the existing hydrogels generally have problems of weak tensile capacity, insufficient durability, and being easy to freeze at low temperatures, which greatly affect their application in the field of wearable devices. In this paper, glycerol was partially replaced by water as the solvent, agar was thermally dissolved to initiate acrylamide polymerization, and MXene was used as a conductive filler and initiator promoter to form the double network MXene-PAM/Agar organic hydrogel. The presence of MXene makes the hydrogel produce more conductive paths and enforces the hydrogel’s higher conductivity (1.02 S·m−1). The mechanical properties of hydrogels were enhanced by the double network structure, and the hydrogel had high stretchability (1300%). In addition, the hydrogel-based wearable strain sensor exhibited good sensitivity over a wide strain range (GF = 2.99, 0–200% strain). The strain sensor based on MXene-PAM/Agar hydrogel was capable of real-time monitoring of human movement signals such as fingers, wrists, arms, etc. and could maintain good working conditions even in cold environments (−26 °C). Hence, we are of the opinion that delving into this hydrogel holds the potential to broaden the scope of utilizing conductive hydrogels as flexible and wearable strain sensors, especially in chilly environments.
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Maikovych, O. V., I. A. Dron, N. M. Bukartyk, O. Yu Bordeniuk, and N. G. Nosova. "Іnvestigation of gel formation peculiarities and properties of hydrogels obtained by the structuring of acrylamide prepolymers." Chemistry, Technology and Application of Substances 4, no. 1 (June 1, 2021): 179–85. http://dx.doi.org/10.23939/ctas2021.01.179.
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The paper represents the results of the investigation of the formation of a polymeric matrix of hydrogel due to the structuring of polyacrylamide using its reactive polymeric derivative – poly-N- (hydroxymethyl) acrylamide. Research determined zones of optimum conditions of synthesis and characterized hydrogel depending on pH of media, the ratio between the concentration of prepolymers, and time of synthesis. The investigation of the reaction mixture showed that the hydrogen index of the synthesis of hydrogels is one of the important factors, which in the design of the polymer framework of hydrogels allows regulating their colloidal chemical properties in a wide range.
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Feyissa, Zerihun, Gemechu Deressa Edossa, Tariku Bayisa Bedasa, and Leta Guta Inki. "Fabrication of pH-Responsive Chitosan/Polyvinylpyrrolidone Hydrogels for Controlled Release of Metronidazole and Antibacterial Properties." International Journal of Polymer Science 2023 (April 18, 2023): 1–18. http://dx.doi.org/10.1155/2023/1205092.
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This research focused on preparing hydrogels with controlled drug release properties to control gastrointestinal tract bacterial infection. Chitosan (CS) and polyvinylpyrrolidone (PVP) were used as the base polymers, with the CS component crosslinked by glutaraldehyde for hydrogel preparation using the solution casting technique. The effect of varying glutaraldehyde content in the hydrogels was characterized by the extent of swelling in simulated physiological fluids of pH 1.2, 6.8, and 7.4; the development of porosity; and gel fraction. Functional groups and covalent and hydrogen bonds formed, thermal stability, phase structure, and morphology were characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. The results show that the components in the hydrogels have good compatibility and formed honeycomb-like structures. In vitro studies confirmed that the hydrogels have good biodegradability at pH 7.4. Based on these properties, a CS/PVP hydrogel of the ratio of 60 : 40 crosslinked with 600 μL glutaraldehyde was selected for the in-situ loading of 200 mg of the drug metronidazole (MTZ). The hydrogel was characterized for cumulative drug release in the simulated physiological fluids and drug release kinetics using different models and for its antibacterial activity. The best-fit Korsmeyer–Peppas model suggests that MTZ release followed diffusion and swelling-controlled time-dependent non-Fickian transport related to hydrogel erosion. This hydrogel displays enhanced antimicrobial activity against Staphylococcus aureus, and Escherichia coli showed substantial inhibition zones indicating the produced CS/PVP hydrogels are promising candidates for controlled drug release applications.
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Zhu, Wantong. "One-step soaking strategy toward mechanical double-network hydrogel." Highlights in Science, Engineering and Technology 116 (November 7, 2024): 21–26. http://dx.doi.org/10.54097/4hreyy45.
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Double-network (DN) hydrogels, which comprise noncovalent interacting networks, are highly sought after due to their controlled compositions and environmental friendliness. However, the complex preparation methods hinder the application of these hydrogels. In this study, we present a simple and feasible approach for fabricating hybrid PAA-CS DN hydrogels by post-treating the PAA-CS composite hydrogels with CuSO4 solutions to induce the formation of physical networks through CS chain entanglement. The composite hydrogel, composed of chitosan (CS) and polyacrylic acid (PAA), readily transforms into a DN hydrogel after soaking in a CuSO4 solution, thanks to in situ formation of chain entanglements, hydrogen bonds, and ionic coordination. The resulting hybrid DN hydrogels exhibit porous networks, high tensile strength, and exceptional toughness. This facile but effective soaking method can be universally applied to fabricate mechanically robust hydrogels, modulate noncovalent interactions, and broaden their potential applications.
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Liu, Shengda, Shengchao Deng, Tengfei Yan, Xin Zhang, Ruizhen Tian, Jiayun Xu, Hongcheng Sun, Shuangjiang Yu, and Junqiu Liu. "Biocompatible Diselenide-Containing Protein Hydrogels with Effective Visible-Light-Initiated Self-Healing Properties." Polymers 13, no. 24 (December 13, 2021): 4360. http://dx.doi.org/10.3390/polym13244360.
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Smart hydrogels are typical functional soft materials, but their functional and mechanical properties are compromised upon micro- or macro-mechanical damage. In contrast, hydrogels with self-healing properties overcome this limitation. Herein, a dual dynamic bind, cross-linked, self-healing protein hydrogel is prepared, based on Schiff base bonds and diselenide bonds. The Schiff base bond is a typical dynamic covalent bond and the diselenide bond is an emerging dynamic covalent bond with a visible light response, which gives the resulting hydrogel a dual response in visible light and a desirable self-healing ability. The diselenide-containing protein hydrogels were biocompatible due to the fact that their main component was protein. In addition, the hydrogels loaded with glucose oxidase (GOx) could be transformed into sols in glucose solution due to the sensitive response of the diselenide bonds to the generated hydrogen peroxide (H2O2) by enzymatic catalysis. This work demonstrated a diselenide-containing protein hydrogel that could efficiently self-heal up to nearly 100% without compromising their mechanical properties under visible light at room temperature.
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Yu, Jie, Fangli Ran, Chenyu Li, Zhenxin Hao, Haodong He, Lin Dai, Jingfeng Wang, and Wenjuan Yang. "A Lignin Silver Nanoparticles/Polyvinyl Alcohol/Sodium Alginate Hybrid Hydrogel with Potent Mechanical Properties and Antibacterial Activity." Gels 10, no. 4 (April 1, 2024): 240. http://dx.doi.org/10.3390/gels10040240.
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Antibacterial hydrogels have attracted significant attention due to their diverse applications, efficient antimicrobial properties, and adaptability to various environments and requirements. However, their relatively fragile structure, coupled with the potential for environmental toxicity when exposed to their surroundings for extended periods, may significantly limit their practical application potential. In this work, a composite hydrogel was synthesized with outstanding mechanical features and antibacterial capability. The hydrogel was developed through the combination of the eco-friendly and enduring antibacterial agent, lignin silver nanoparticles (Lig-Ag NPs), with polyvinyl alcohol (PVA) and sodium alginate (SA), in varying proportions. The successful synthesis of the hydrogel and the dispersed distribution of Lig-Ag NPs within the hydrogel were confirmed by various analytical techniques, including field emission scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), mercury intrusion porosimetry (MIP), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The formation of multiple hydrogen bonds between Lig-Ag NPs and the composites contributed to a more stable and dense network structure of the hydrogel, consequently enhancing its mechanical properties. Rheological tests revealed that the hydrogel exhibited an elastic response and demonstrated outstanding self-recovery properties. Significantly, the antibacterial hydrogel demonstrated effectiveness against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), achieving a <5% survival of bacteria within 12 h. This study presented a green and straightforward synthetic strategy for the application of antibacterial composite hydrogels in various fields.
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Popov, Sergey, Nikita Paderin, Elizaveta Chistiakova, Alisa Sokolova, Ilya V. Konyshev, Vladislav S. Belozerov, and Andrey A. Byvalov. "Swelling, Protein Adsorption, and Biocompatibility of Pectin–Chitosan Hydrogels." Gels 10, no. 7 (July 17, 2024): 472. http://dx.doi.org/10.3390/gels10070472.
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The study aims to determine how chitosan impacts pectin hydrogel’s ability to attach peritoneal leukocytes, activate complement, induce hemolysis, and adsorb blood proteins. The hydrogels PEC-Chi0, PEC-Chi25, PEC-Chi50, and PEC-Chi75 were prepared by placing a mixture solution of 4% pectin and 4% chitosan in a ratio of 4:0, 3:1, 2:2, and 1:3 in a solution of 1.0 M CaCl2. Chitosan was found to modify the mechanical properties of pectin–calcium hydrogels, such as hardness and cohesiveness-to-adhesiveness ratio. Chitosan in the pectin–calcium hydrogel caused pH-sensitive swelling in Hanks’ solution. The PEC-Chi75 hydrogel was shown to adsorb serum proteins at pH 7.4 to a greater extent than other hydrogels. PEC-Chi75’s strong adsorption capacity was related to lower peritoneal leukocyte adherence to its surface when compared to other hydrogels, showing improved biocompatibility. Using the optical tweezers approach, it was shown that the force of interaction between pectin–chitosan hydrogels and plasma proteins increased from 10 to 24 pN with increasing chitosan content from 0 to 75%. Thus, the properties of pectin–calcium hydrogel, which determine interactions with body tissues after implantation, are improved by the addition of chitosan, making pectin–chitosan hydrogel a promising candidate for smart biomaterial development.
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Jiang, Hai Ling. "Network Structure and Water Absorption of Soil Moisture Gel by Coarse-Grained Molecular Dynamics Simulations." International Journal of Engineering Research in Africa 63 (March 30, 2023): 1–12. http://dx.doi.org/10.4028/p-r8o1xc.
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With the wide application of hydrogel materials in agriculture, forestry, flexible electronics, electronic information engineering, environmental detection, flexible electronics, information science, technology and so on, the development of various new functional hydrogel materials has gradually become one of the research hotspots. At present, the research on hydrogel materials is mainly focused on the preparation of various functional hydrogels by experimental methods, there is no fundamental understanding of the relationship between the “stimulus-response” and its inner microstructures. In this paper, the author uses the molecular dynamics simulation method to study the evolution of the hydrogel’s microscopic network structure, the relationship between microstructure and water absorption of hydrogels in the processes of water swelling and “stimulus-response”. The next generation of new super absorbent, high toughness, high strength and other functional hydrogels could be synthesized by the guide of this study, and these new hydrogels have a promising future to apply in new fields of technology such as flexible electronics, and biological medicine.
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He, Jiaqing, Qiang Zhou, Zhiqing Ge, Shunfeng Jiang, Jiahe Li, Wei Feng, and Haiyang Yang. "pH‐Gated Switch of LCST‐UCST Phase Transition of Hydrogels." Advanced Functional Materials, May 14, 2024. http://dx.doi.org/10.1002/adfm.202404341.
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AbstractTemperature‐responsive hydrogels including lower critical solution temperature (LCST)‐ and upper critical solution temperature (UCST)‐type hydrogels are attractive in various fields. However, the swift switch between LCST and UCST stimuli‐responsive behaviors remains intriguing and challenging. Here is reported a kind of hydrogel with pH‐gated LCST and UCST response behaviors. This is achieved using the hydrogen bonding between carboxylic acid groups of poly(acrylic acid‐co‐acrylamide) and hydroxyl groups of hydroxypropyl cellulose (HPC). The poly(acrylic acid‐co‐acrylamide)‐HPC (PACA‐HPC) hydrogels exhibit pH‐gated reversible LCST‐UCST phase transition behavior. When the transparent PACA‐HPC hydrogel is placed in an acid bath, the COO− groups get protonated, rapidly forming hydrogen bonds with HPC to render a light‐scattering state making the hydrogel opaque. Furthermore, the opaque hydrogel exhibits UCST phase transition behavior at 20–45 °C. When the opaque PCAC‐HPC hydrogel is placed in an alkaline environment, hydrogen‐bonded complexes gradually dissociate as the COOH groups are deprotonated to form a homogeneous transparent state. The transparent hydrogel exhibits LCST phase transition behavior at 20–45° C. Therefore, is shown the hydrogen bonding strategy to fabricate hydrogels with tunable LCST and UCST responses. With this pH‐gated hydrogel with switchable LCST/UCST responsive behaviors, are demonstrated its applications in smart windows and information encryption.
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Inman, Daniel, Veronika Kozlovskaya, Pavel Nikishau, Sarah Nealy, Maksim Dolmat, Jonghwa Oh, Claudiu T. Lungu, Lynzi Hunter, and Eugenia Kharlampieva. "Multilayer Hydrogel Microcubes: Effects of Templating Particle Morphology on Cubic Hydrogel Properties." Macromolecular Materials and Engineering, October 24, 2023. http://dx.doi.org/10.1002/mame.202300284.
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AbstractNon‐spherical stimuli‐responsive polymeric particles have shown critical importance in therapeutic delivery. Herein, pH‐responsive poly(methacrylic acid) (PMAA) cubic hydrogel microparticles are synthesized by crosslinking PMAA layers within PMAA/poly(N‐vinylpyrrolidone) hydrogen‐bonded multilayers templated on porous inorganic microparticles. This study investigates the effects of template porosity and surface morphology on the PMAA multilayer hydrogel microcube properties. It is found that the hydrogel structure depends on the template's calcination time and temperature. The pH‐triggered PMAA hydrogel cube swelling depends on the hydrogel's internal architecture, either hollow capsule‐like or non‐hollow continuous hydrogels. The loading efficiency of the doxorubicin (DOX) drug inside the microcubes is analyzed by high‐performance liquid chromatography (HPLC), and shows the dependenceof the drug uptake on the network structure and morphology controlled by the template porosity. Varying the template calcination from low (300 °C) to high (1000 °C) temperature results in a 2.5‐fold greater DOX encapsulation by the hydrogel cubes. The effects of hydrogel surface charge on the DOX loading and release are also studied using zeta‐potential measurements. This work provides insight into the effect of structural composition, network morphology, and pH‐induced swelling of the cubical hydrogels and may advance the development of stimuli‐responsive vehicles for targeted anticancer drug delivery.
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Li, Qi, Luochang Wang, Qihan Liu, Wei Hong, and Canhui Yang. "Fatigue Damage–Resistant Physical Hydrogel Adhesion." Frontiers in Robotics and AI 8 (April 15, 2021). http://dx.doi.org/10.3389/frobt.2021.666343.
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Strong adhesion between hydrogels and various engineering surfaces has been achieved; yet, achieving fatigue-resistant hydrogel adhesion remains challenging. Here, we examine the fatigue of a specific type of hydrogel adhesion enabled by hydrogen bonds and wrinkling and show that the physical interactions–based hydrogel adhesion can resist fatigue damage. We synthesize polyacrylamide hydrogel as the adherend and poly(acrylic acid-co-acrylamide) hydrogel as the adhesive. The adherend and the adhesive interact via hydrogen bonds. We further introduce wrinkles at the interface by biaxially prestretching and then releasing the adherends and perform butt-joint tests to probe the adhesion performance. Experimental results reveal that the samples with a wrinkled interface resist fatigue damage, while the samples with a flat interface fail in ~9,000 cycles at stress levels of 70 and 63% peak stresses in static failure. The endurance limit of the wrinkled-interface samples is comparable to the peak stress of the flat-interface samples. Moreover, we find that the nearly perfectly elastic polyacrylamide hydrogel also suffers fatigue damage, which limits the fatigue life of the wrinkled-interface samples. When cohesive failure ensues, the evolutions of the elastic modulus of wrinkled-interface samples and hydrogel bulk, both in satisfactory agreements with the predictions of damage accumulation theory, are alike. We observe similar behaviors in different material systems with polyacrylamide hydrogels with different water contents. This work proves that physical interactions can be engaged in engineering fatigue-resistant adhesion between soft materials such as hydrogels.
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Wang, Yajun, Yiyan Gao, Kai Shi, and Guanghui Gao. "Xanthan gum‐enhanced polyvinyl alcohol hydrogel toward flexible sensor." Journal of Polymer Science, February 29, 2024. http://dx.doi.org/10.1002/pol.20230924.
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AbstractIonic conductive hydrogels attracted much attention for applying as wearable sensors, but most hydrogel sensors were not strong enough to withstand repeated sensing because of their low mechanical strength. Here, xanthan gum and sodium chloride were introduced into the polyvinyl alcohol hydrogel system for constructing hydrogels with high mechanical strength due to the hydrogen bonds formed between polyvinyl alcohol and gum xanthan as well as the chain entanglement of polyvinyl alcohol. Meanwhile, the hydrogel was highly sensitive to mechanical deformation because of the existence of free ions provided by sodium chloride. As a result, the hydrogel could serve as sensors for perceiving various body motions, with the advantages of fast response, reproducibility and durability for repeated stretching or compression. The strategy of xanthan gum‐enhanced hydrogel fuels an exciting new direction for hydrogel‐based wearable sensors.
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Yu, Han, Qiaohong Xiao, Guilin Qi, Feixiang Chen, Biyue Tu, Suo Zhang, Yinping Li, Yun Chen, Hui Yu, and Peng Duan. "A Hydrogen Bonds-Crosslinked Hydrogels With Self-Healing and Adhesive Properties for Hemostatic." Frontiers in Bioengineering and Biotechnology 10 (April 14, 2022). http://dx.doi.org/10.3389/fbioe.2022.855013.
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Hydrogels with adhesive properties have the potential for rapid haemostasis and wound healing in uncontrolled non-pressurized surface bleeding. Herein, a typical hydrogen bond-crosslinked hydrogel with the above functions was constructed by directly mixing solutions of humic acid (HA) and polyvinylpyrrolidone (PVP), in which the HA worked as a crosslinking agent to form hydrogen bonds with the PVP. By altering the concentration of HA, a cluster of stable and uniform hydrogels were prepared within 10 s. The dynamic and reversible nature of the hydrogen bonds gave the HA/PVP complex (HPC) hydrogels injectability and good flexibility, as well as a self-healing ability. Moreover, the numerous functional groups in the hydrogels enhanced the cohesion strength and interaction on the interface between the hydrogel and the substrate, endowing them with good adhesion properties. The unique chemical composition and cross-linking mechanism gave the HPC hydrogel good biocompatibility. Taking advantage of all these features, the HPC hydrogels obtained in this work were broadly applied as haemostatic agents and showed a good therapeutic effect. This work might lead to an improvement in the development of multifunctional non-covalent hydrogels for application to biomaterials.
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Liu, Desheng, Pan Jiang, Yue Hu, Yaozhong Lu, Yixian Wang, Jiayu Wu, Danli Hu, Tao Wu, and Xiaolong Wang. "Slippery Hydrogel with Desiccation-Tolerant "Skin" for High-Precision Additive Manufacturing." International Journal of Extreme Manufacturing, December 19, 2023. http://dx.doi.org/10.1088/2631-7990/ad1730.
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Abstract Hydrogels inevitably undergo dehydration, structural collapse, and shrinkage deformation due to the uninterrupted evaporation in the atmosphere, thereby losing their flexibility, slippery, and manufacturing precision. Here, we propose a novel bioinspired strategy to construct a spontaneously formed “skin” on the slippery hydrogels by incorporating biological stress metabolites trehalose into the hydrogel network, which can generate robust hydrogen bonding interactions to restrain water evaporation. The contents of trehalose in hydrogel matrix can also regulate the desiccation-tolerance, mechanical properties, and lubricating performance of slippery hydrogels in a wide range. Combining vat photopolymerization 3D printing and trehalose-modified slippery hydrogels enables to achieve the structural hydrogels with high resolution, shape fidelity, and sophisticated architectures, instead of structural collapse and shrinkage deformation caused by dehydration. And thus, this proposed functional hydrogel adapts to manufacture large-scale hydrogels with sophisticated architectures in a long-term process. As a proof-of-concept demonstration, a high-precision and sophisticated slippery hydrogel vascular phantom was easily fabricated to imitate guidewire intervention. Additionally, the proposed protocol is universally applicable to diverse types of hydrogel systems. This strategy opens up a versatile methodology to fabricate dry-resistant slippery hydrogel for functional structures and devices, expanding their high-precision processing and broad applications in the atmosphere.