Journal articles on the topic 'Hydrogen'
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1
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.
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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.
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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.
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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.
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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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Fan, Xiangchao, Zhaojun Chen, Haotian Sun, Sijia Zeng, Ruonan Liu, and Ye Tian. "Polyelectrolyte-based conductive hydrogels: from theory to applications." Soft Science 2, no. 3 (2022): 10. http://dx.doi.org/10.20517/ss.2022.09.
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With the continuous development of soft conductive materials, polyelectrolyte-based conductive hydrogels have gradually become a major research hotspot because of their strong application potential. This review first considers the basic conductive theory of hydrogels, which can be divided into the hydrogel structure and zwitterionic enhancing conductivity theories. We then classify polyelectrolyte-based conductive hydrogels into different types, including double, ionic-hydrogen bond, hydrogen bond，and physically crosslinked networks. Furthermore, the mechanical, electrical, and self-healing properties and fatigue and temperature interference resistance of polyelectrolyte-based conductive hydrogels are described in detail. We then discuss their versatile applications in strain sensors, solid-state supercapacitors, visual displays, wound dressings, and drug delivery. Finally, we offer perspectives on future research trends for polyelectrolyte-based conductive hydrogels.
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Cai, Hao-Kun, Zhong-Yi Jiang, Siyuan Xu, Ying Xu, Ping Lu, and Jian Dong. "Polymer Hydrogel Supported Ni/Pd Alloys for Hydrogen Gas Production from Hydrolysis of Dimethylamine Borane with a Long Recyclable Lifetime." Polymers 14, no. 21 (November 1, 2022): 4647. http://dx.doi.org/10.3390/polym14214647.
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Hydrogen gas production can be produced from dimethylamine borane by the catalytic effect of metal nanoparticles. Past research efforts were heavily focused on dehydrogenation in organic solvents. In this study, hydrolysis of the borane in aqueous solutions was investigated, which bears two significant advantages: that two-thirds of the hydrogen generated originate from water and that the hydrogen storage materials are non-flammable. Polymer hydrogels serve as good carriers for metal particles as catalysts in aqueous solutions. Kinetic analysis of hydrogen production was performed for Ni/Pd bimetallic nanoclusters dispersed in a polymer hydrogel with a 3-D network structure. The reaction catalyzed by the bimetallic nanoclusters has an activation energy of only 34.95 kJ/mol, considerably lower than that by Ni or other metal catalysts reported. A significant synergistic effect was observed in the Ni/Pd bimetallic catalysts (Ni–Pd = 20/1) with a higher activity than Pd or Ni alone. This proves the alloy nature of the nanoparticles in the borane hydrolysis and the activation of water and borane by both metals to break the O–H and B–H bonds. The hydrogel with the Ni/Pd metal can be recycled with a much longer lifetime than all the previously prepared catalysts. The aqueous borane solutions with a polymer hydrogel can become a more sustainable hydrogen supplier for long-term use.
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Mucaria, Angelica, Demetra Giuri, Claudia Tomasini, Giuseppe Falini, and Devis Montroni. "Tunable Oxidized-Chitin Hydrogels with Customizable Mechanical Properties by Metal or Hydrogen Ion Exposure." Marine Drugs 22, no. 4 (April 3, 2024): 164. http://dx.doi.org/10.3390/md22040164.
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This study focuses on the optimization of chitin oxidation in C6 to carboxylic acid and its use to obtain a hydrogel with tunable resistance. After the optimization, water-soluble crystalline β-chitin fibrils (β-chitOx) with a degree of functionalization of 10% were obtained. Diverse reaction conditions were also tested for α-chitin, which showed a lower reactivity and a slower reaction kinetic. After that, a set of hydrogels was synthesized from β-chitOx 1 wt.% at pH 9, inducing the gelation by sonication. These hydrogels were exposed to different environments, such as different amounts of Ca2+, Na+ or Mg2+ solutions, buffered environments such as pH 9, PBS, pH 5, and pH 1, and pure water. These hydrogels were characterized using rheology, XRPD, SEM, and FT-IR. The notable feature of these hydrogels is their ability to be strengthened through cation chelation, being metal cations or hydrogen ions, with a five- to tenfold increase in their storage modulus (G’). The ions were theorized to alter the hydrogen-bonding network of the polymer and intercalate in chitin’s crystal structure along the a-axis. On the other hand, the hydrogel dissolved at pH 9 and pure water. These bio-based tunable hydrogels represent an intriguing material suitable for biomedical applications.
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Jiang, Weihui, Peiyao Shen, and Ju Gu. "Nanocrystalline cellulose prepared by double oxidation as reinforcement in polyvinyl alcohol hydrogels." Journal of Polymer Engineering 40, no. 1 (December 18, 2019): 67–74. http://dx.doi.org/10.1515/polyeng-2019-0258.
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Abstract As a biopolymer with high mechanical strength, nanocellulose was increasingly studied to improve polymer properties. In this study, nanocrystalline cellulose (NCC) was efficiently isolated from eucalyptus pulp by double oxidation (ammonium persulfate oxidation and ultrasonic oxidation). The total yield of NCC (405.1 ± 180.5 nm long and 31.7 ± 9.5 nm wide) was 38.3%. A novel hybrid hydrogel was produced from polyvinyl alcohol (PVA) and NCC using the freeze-thaw technique. In this hybrid architecture, hydrogen bonds were formed between PVA and NCC. With the increasing proportion of NCC, the pore size of hydrogels shank gradually and the structure of the hybrid hydrogels became denser. The tensile strength of PVA/NCC hybrid hydrogels increased by 42.4% compared to the neat PVA hydrogel. The results showed that NCC can improve the swelling, thermal properties, and water evaporation rate of PVA hydrogels due to the hydrophilic hydroxyl groups of NCC and hydrogen bonds between PVA and NCC, indicating that PVA hydrogels would have a wider range of application due to the existence of NCC, a green hybrid filler. Most importantly, this novel double oxidation method for preparing nanocellulose will promote an efficient production of nanocellulose.
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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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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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Kumar Soni, Rakesh, Shailesh M Kewatkar, Vidhi Jain, and Manmeet Singh Saluja. "A Review of Hydrogels, with its Properties and Applications in Medicine." Journal of Biomedical and Pharmaceutical Research 12, no. 2 (April 3, 2023): 20–33. http://dx.doi.org/10.32553/jbpr.v12i2.970.
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A hydrogel is an insoluble in water three-dimensional polymer network that has the potential to absorb bodily fluids in a biological setting. Hydrogels may also be used in medical applications. Chemical crosslinking mechanisms such as optical polymerization, enzymatic reactions, and physical crosslinking mechanisms such as temperature- and pH-dependent processes, as well as ionic crosslinking, are all responsible for the formation of a network of polymers of this kind. Both physical and chemical hydrogels may be generated by the application of weak secondary forces, but chemical hydrogels can also be formed through the application of covalent forces. Hydrogels may be made from a wide variety of polymers derived from either natural or synthetic sources. The swelling, the mechanical characteristics, and the biological properties of hydrogels are some of the most essential aspects of hydrogels, and each of these qualities may have an effect on the structure and morphology of the hydrogel. Hydrogen is utilized in a variety of medical applications, including tissue engineering, contact lenses, wound dressings, and the release of therapeutic agents. This is possible because hydrogen has a structure that is analogous to the extracellular matrix (ECM), and it also has the ability to absorb water. There is a discussion on hydrogels, the many varieties of hydrogels, the characteristics of hydrogels, and their uses in medicine.
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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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Jeon, Dasom, Jinwoo Park, Changhwan Shin, Hyunwoo Kim, Ji-Wook Jang, Dong Woog Lee, and Jungki Ryu. "Superaerophobic hydrogels for enhanced electrochemical and photoelectrochemical hydrogen production." Science Advances 6, no. 15 (April 2020): eaaz3944. http://dx.doi.org/10.1126/sciadv.aaz3944.
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The efficient removal of gas bubbles in (photo)electrochemical gas evolution reactions is an important but underexplored issue. Conventionally, researchers have attempted to impart bubble-repellent properties (so-called superaerophobicity) to electrodes by controlling their microstructures. However, conventional approaches have limitations, as they are material specific, difficult to scale up, possibly detrimental to the electrodes’ catalytic activity and stability, and incompatible with photoelectrochemical applications. To address these issues, we report a simple strategy for the realization of superaerophobic (photo)electrodes via the deposition of hydrogels on a desired electrode surface. For a proof-of-concept demonstration, we deposited a transparent hydrogel assembled from M13 virus onto (photo)electrodes for a hydrogen evolution reaction. The hydrogel overlayer facilitated the elimination of hydrogen bubbles and substantially improved the (photo)electrodes’ performances by maintaining high catalytic activity and minimizing the concentration overpotential. This study can contribute to the practical application of various types of (photo)electrochemical gas evolution reactions.
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Iresha, Harshani, and Takaomi Kobayashi. "In Situ Viscoelasticity Behavior of Cellulose–Chitin Composite Hydrogels during Ultrasound Irradiation." Gels 7, no. 3 (June 30, 2021): 81. http://dx.doi.org/10.3390/gels7030081.
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Composite hydrogels with different cellulose and chitin loading were prepared, and their in-situ viscoelastic properties were estimated under cyclic exposure of 43 kHz and 30 W ultrasound (US) using a sono-deviced rheometer. US transmitted into the hydrogel caused it to soften within about 10 sec, thus causing a decline in the storage modulus (G′) and loss modulus (G″). However, when the US was stopped, the G′ and G″ returned to their initial values. Here, G′ dropped gradually in response to the US irradiation, especially in the first cycle. After the second and third cycles, the decline was much quicker, within a few seconds. When the chitin component in the hydrogel was increased, the drop was significant. FTIR analysis of the hydrogels suggested that the peaks of -OH stretching and amide I vibration near 1655 cm−1 shifted towards lower wave numbers after the third cycle, meaning that the US influenced the hydrogen bonding interaction of the chitin amide group. This repetitive effect contributed to the breakage of hydrogen bonds and increased the interactions of the acetylamine group in chitin and in the -OH groups. Eventually, the matrix turned into a more stabilized hydrogel.
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Hamri, Salah, Bouchra Bouzi, Djahida Lerari, Fayçal Dergal, Tewfik Bouchaour, Khaldoun Bachari, Zohra Bouberka, and Ulrich Maschke. "Removal of Malachite Green by Poly(acrylamide-co-acrylic acid) Hydrogels: Analysis of Coulombic and Hydrogen Bond Donor–Acceptor Interactions." Gels 9, no. 12 (December 1, 2023): 946. http://dx.doi.org/10.3390/gels9120946.
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Water pollution caused by dyes poses a significant threat to life on earth. Poly(acrylamide-co-acrylic acid) hydrogels are widely used to treat wastewater from various pollutants. This study aims to examine the removal of malachite green (MG), a harmful and persistent dye that could cause extensive environmental damage, from an aqueous solution by adjusting the initial concentration of acrylamide (AM) and the degree of copolymer crosslinking. The copolymer hydrogels efficiently eliminate MG in a brief timeframe. The most successful hydrogel accomplished a removal rate exceeding 96%. The copolymer of 4 wt % 1,6-hexanediol diacrylate and a concentration of 100 mg/mL AM was effective. The degree of swelling was affected by crosslinking density as expected, with low crosslinking ratios resulting in significant swelling and high ratios resulting in less swelling. To evaluate the results, a docking approach was used which presented three crosslinked models: low, medium, and high. The copolymer–dye hydrogel system displayed robust hydrogen bonding interactions, as confirmed by the high quantities of both donors and acceptors. It was determined that MG contains six rotatable bonds, enabling it to adapt and interact with the copolymer chains. The dye and copolymer enhance H-bond formation by providing two hydrogen bond donors and 16 hydrogen bond acceptors, respectively. Through capitalizing on cationic and anionic effects, the ionic MG/copolymer hydrogel system improves retention efficiency by enhancing attraction between opposing charges. It is interesting to note that the synthesized copolymer is able to remove 96.4% of MG from aqueous media within one hour of contact time.
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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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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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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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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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Zomrawi, Dr Albashir, and K. AlNaimee. "Comparison Study Between Hydrogen Palladium Sensor and Hydrogen Manganese Dioxide Sensor." International Journal of Trend in Scientific Research and Development Volume-2, Issue-4 (June 30, 2018): 912–17. http://dx.doi.org/10.31142/ijtsrd13088.
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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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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, Bing, Xu Zhang, Kening Wan, Jixin Zhu, Jingsan Xu, Chao Zhang, and Tianxi Liu. "Dense Hydrogen-Bonding Network Boosts Ionic Conductive Hydrogels with Extremely High Toughness, Rapid Self-Recovery, and Autonomous Adhesion for Human-Motion Detection." Research 2021 (April 15, 2021): 1–14. http://dx.doi.org/10.34133/2021/9761625.
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The construction of ionic conductive hydrogels with high transparency, excellent mechanical robustness, high toughness, and rapid self-recovery is highly desired yet challenging. Herein, a hydrogen-bonding network densification strategy is presented for preparing a highly stretchable and transparent poly(ionic liquid) hydrogel (PAM-r-MVIC) from the perspective of random copolymerization of 1-methyl-3-(4-vinylbenzyl) imidazolium chloride and acrylamide in water. Ascribing to the formation of a dense hydrogen-bonding network, the resultant PAM-r-MVIC exhibited an intrinsically high stretchability (>1000%) and compressibility (90%), fast self-recovery with high toughness (2950 kJ m-3), and excellent fatigue resistance with no deviation for 100 cycles. Dissipative particle dynamics simulations revealed that the orientation of hydrogen bonds along the stretching direction boosted mechanical strength and toughness, which were further proved by the restriction of molecular chain movements ascribing to the formation of a dense hydrogen-bonding network from mean square displacement calculations. Combining with high ionic conductivity over a wide temperature range and autonomous adhesion on various surfaces with tailored adhesive strength, the PAM-r-MVIC can readily work as a highly stretchable and healable ionic conductor for a capacitive/resistive bimodal sensor with self-adhesion, high sensitivity, excellent linearity, and great durability. This study might provide a new path of designing and fabricating ionic conductive hydrogels with high mechanical elasticity, high toughness, and excellent fatigue resilience for skin-inspired ionic sensors in detecting complex human motions.
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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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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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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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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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Okay, Oguz. "Re-Entrant Conformation Transition in Hydrogels." Gels 7, no. 3 (July 20, 2021): 98. http://dx.doi.org/10.3390/gels7030098.
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Hydrogels are attractive materials not only for their tremendous applications but also for theoretical studies as they provide macroscopic monitoring of the conformation change of polymer chains. The pioneering theoretical work of Dusek predicting the discontinuous volume phase transition in gels followed by the experimental observation of Tanaka opened up a new area, called smart hydrogels, in the gel science. Many ionic hydrogels exhibit a discontinuous volume phase transition due to the change of the polymer–solvent interaction parameter χ depending on the external stimuli such as temperature, pH, composition of the solvent, etc. The observation of a discontinuous volume phase transition in nonionic hydrogels or organogels is still a challenging task as it requires a polymer–solvent system with a strong polymer concentration dependent χ parameter. Such an observation may open up the use of organogels as smart and hydrophobic soft materials. The re-entrant phenomenon first observed by Tanaka is another characteristic of stimuli responsive hydrogels in which they are frustrated between the swollen and collapsed states in a given solvent mixture. Thus, the hydrogel first collapses and then reswells if an environmental parameter is continuously increased. The re-entrant phenomenon of hydrogels in water–cosolvent mixtures is due to the competitive hydrogen-bonding and hydrophobic interactions leading to flow-in and flow-out of the cosolvent molecules through the hydrogel moving boundary as the composition of the solvent mixture is varied. The experimental results reviewed here show that a re-entrant conformation transition in hydrogels requires a hydrophobically modified hydrophilic network, and a moderate hydrogen-bonding cosolvent having competitive attractions with water and polymer. The re-entrant phenomenon may widen the applications of the hydrogels in mechanochemical transducers, switches, memories, and sensors.
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Chen, Ying, Xiaomin Wang, Yudong Huang, Peipei Kuang, Yushu Wang, Yong Liu, Weihan Yin, et al. "In Situ-Forming Cellulose/Albumin-Based Injectable Hydrogels for Localized Antitumor Therapy." Polymers 13, no. 23 (December 1, 2021): 4221. http://dx.doi.org/10.3390/polym13234221.
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Injectable hydrogels, which are formed in situ by changing the external stimuli, have the unique characteristics of easy handling and minimal invasiveness, thus providing the advantage of bypass surgical operation and improving patient compliance. Using external temperature stimuli to realize the sol-to-gel transition when preparing injectable hydrogel is essential since the temperature is stable in vivo and controllable during ex vivo, although the hydrogels obtained possibly have low mechanical strength and stability. In this work, we designed an in situ fast-forming injectable cellulose/albumin-based hydrogel (HPC-g-AA/BSA hydrogels) that responded to body temperature and which was a well-stabilized hydrogen-bonding network, effectively solving the problem of poor mechanical properties. The application of localized delivery of chemotherapeutic drugs of HPC-g-AA/BSA hydrogels was evaluated. In vitro and in vivo results show that HPC-g-AA/BSA hydrogels exhibited higher antitumor efficacy of reducing tumor size and seem ideal for localized antitumor therapy.
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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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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.
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VM, Aroutiounian. "Hydrogen Peroxide Gas Sensors." Physical Science & Biophysics Journal 5, no. 2 (2021): 1–22. http://dx.doi.org/10.23880/psbj-16000194.
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The results of studies of many types of semiconductor H 2 O 2 sensors are discussed in this review of 195 articles about hydrogen peroxide. The properties of electrochemical detectors, sensors based on organic and inorganic materials, graphene, and nano-sensors are analyzed. Optical and fluorescent sensors, detectors made of porous materials, quantum dots, fibers, and spheres are briefly discussed. The results of our studies in the YSU of hydrogen peroxide sensors made from solid solutions of carbon nanotubes with semiconducting metal oxides are also presented in the review. The fundamentals of the manufacture of biomarkers of respiration containing hydrogen peroxide vapors, which make it possible to judge the degree of a person’s illness with various respiratory diseases (asthma, lung cancer, etc.), are discussed.
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Erikci, Saliha, Patricia Mundinger, and Heike Boehm. "Small Physical Cross-Linker Facilitates Hyaluronan Hydrogels." Molecules 25, no. 18 (September 11, 2020): 4166. http://dx.doi.org/10.3390/molecules25184166.
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In this study, we demonstrate that small charged molecules (NH4+, GluA+, dHA+) can form physical cross-links between hyaluronan chains, facilitating polymerization reactions between synthetically introduced thiol groups (HA-DTPH). These hybrid hydrogels can be obtained under physiological conditions ideally suited for 3D cell culture systems. The type and concentration of a physical crosslinker can be adjusted to precisely tune mechanical properties as well as degradability of the desired hydrogel system. We analyze the influence of hydrogen bond formation, concentration and additional ionic interactions on the polymerization reaction of HA-DTPH hydrogels and characterize the resulting hydrogels in regard to mechanical and biocompatibility aspects.
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Mubarok, Wildan, Kelum Chamara Manoj Lakmal Elvitigala, Masaki Nakahata, Masaru Kojima, and Shinji Sakai. "Modulation of Cell-Cycle Progression by Hydrogen Peroxide-Mediated Cross-Linking and Degradation of Cell-Adhesive Hydrogels." Cells 11, no. 5 (March 3, 2022): 881. http://dx.doi.org/10.3390/cells11050881.
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The cell cycle is known to be regulated by features such as the mechanical properties of the surrounding environment and interaction of cells with the adhering substrates. Here, we investigated the possibility of regulating cell-cycle progression of the cells on gelatin/hyaluronic acid composite hydrogels obtained through hydrogen peroxide (H2O2)-mediated cross-linking and degradation of the polymers by varying the exposure time to H2O2 contained in the air. The stiffness of the hydrogel varied with the exposure time. Human cervical cancer cells (HeLa) and mouse mammary gland epithelial cells (NMuMG) expressing cell-cycle reporter Fucci2 showed the exposure-time-dependent different cell-cycle progressions on the hydrogels. Although HeLa/Fucci2 cells cultured on the soft hydrogel (Young’s modulus: 0.20 and 0.40 kPa) obtained through 15 min and 120 min of the H2O2 exposure showed a G2/M-phase arrest, NMuMG cells showed a G1-phase arrest. Additionally, the cell-cycle progression of NMuMG cells was not only governed by the hydrogel stiffness, but also by the low-molecular-weight HA resulting from H2O2-mediated degradation. These results indicate that H2O2-mediated cross-linking and degradation of gelatin/hyaluronic acid composite hydrogel could be used to control the cell adhesion and cell-cycle progression.
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Ouyang, Hongyan, Xiangyan Xie, Yuanjie Xie, Di Wu, Xingqi Luo, Jinrong Wu, Yi Wang, and Lijuan Zhao. "Compliant, Tough, Anti-Fatigue, Self-Recovery, and Biocompatible PHEMA-Based Hydrogels for Breast Tissue Replacement Enabled by Hydrogen Bonding Enhancement and Suppressed Phase Separation." Gels 8, no. 9 (August 25, 2022): 532. http://dx.doi.org/10.3390/gels8090532.
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Although hydrogel is a promising prosthesis implantation material for breast reconstruction, there is no suitable hydrogel with proper mechanical properties and good biocompatibility. Here, we report a series of compliant and tough poly (hydroxyethyl methacrylate) (PHEMA)-based hydrogels based on hydrogen bond-reinforcing interactions and phase separation inhibition by introducing maleic acid (MA) units. As a result, the tensile strength, fracture strain, tensile modulus, and toughness are up to 420 kPa, 293.4%, 770 kPa, and 0.86 MJ/m3, respectively. Moreover, the hydrogels possess good compliance, where the compression modulus is comparable to that of the silicone breast prosthesis (~23 kPa). Meanwhile, the hydrogels have an excellent self-recovery ability and fatigue resistance: the dissipative energy and elastic modulus recover almost completely after waiting for 2 min under cyclic compression, and the maximum strength remains essentially unchanged after 1000 cyclic compressions. More importantly, in vitro cellular experiments and in vivo animal experiments demonstrate that the hydrogels have good biocompatibility and stability. The biocompatible hydrogels with breast tissue-like mechanical properties hold great potential as an alternative implant material for reconstructing breasts.
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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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Li, Zong Sheng. "Density Functional Theory Calculations of Atomic Hydrogen Adsorption on (3, 3) Single-Wall Carbon Nanotubes with Vacancy Defects." Applied Mechanics and Materials 687-691 (November 2014): 4315–18. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.4315.
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In this paper, we have employed density functional theory (DFT) to investigate the adsorption mechanisms of atomic hydrogens on the sidewalls of (3, 3) single-wall carbon nanotubes (CNTs) which have vacancy defects. All the calculations were performed using the generalized gradient approximation (GGA) with the Perdew, Burke and Ernzerhof (PBE) correlation functional.Our results show that hydrogen atoms can chemically adsorb on the defective nanotube. Bonding energy of per hydrogen atom decreases with the number of adsorbed hydrogen atoms. The hydrogen atoms will enhance the electrical conductivity of the (3, 3) nanotube. Besides one hydrogen atom adsorbing on the nanotube with a vacancy defect (MVD), hydrogen atoms move towards the MVD of the nanotube.
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Temel, Sinan, Elif Yaman, Nurgul Ozbay, and Gokmen Ozge. "Synthesis, characterization and adsorption studies of nano-composite hydrogels and the effect of SiO2 on the capacity for the removal of Methylene Blue dye." Journal of the Serbian Chemical Society 85, no. 7 (2020): 939–52. http://dx.doi.org/10.2298/jsc190517114t.
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Nanocomposite hydrogels were produced by free radical polymerization of acrylic acid and N-vinylpyrrolidone in the presence of SiO2 nanoparticles. The chemical and morphological structures of the hydrogels were determined using Fourier transform infra-red spectroscopy (FT-IR) and field emission scanning electron microscopy (FESEM). The nanocomposite hydrogels were used for the adsorption and desorption of Methylene Blue dye from wastewater. Wastewater was referred to distilled water that contained Methylene Blue dye under laboratory conditions. The carbon, hydrogen and nitrogen contents of the dye, hydrogels and dye-adsorbed hydrogels were determined by elemental analysis. The influences of SiO2 nanoparticles and copolymerization on the adsorption capacity were studied. The maximum dye removal of 98.3 % was obtained with AA-co-VP (3:1) copolymeric hydrogel. The synthesized hydrogels could be evaluated as adsorbents in wastewater treatment, effectively.
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Li, Hao, Zhien Zhang, and Zhijian Liu. "Non-Monotonic Trends of Hydrogen Adsorption on Single Atom Doped g-C3N4." Catalysts 9, no. 1 (January 14, 2019): 84. http://dx.doi.org/10.3390/catal9010084.
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To estimate the reaction free energies of the hydrogen evolution reaction (HER) on under-coordinated metallic sites, density function theory (DFT) calculations are usually employed to calculate the hydrogen adsorption energy with an “only-one-hydrogen-adsorption” model, assuming that adsorption with one hydrogen is the most thermodynamically favorable situation during catalysis. In this brief report, we show that on many single atom sites, adsorption of more than one hydrogen is sometimes even more thermodynamically favorable, with the presence of two or three hydrogens resulting in lower adsorption energies. These interesting non-monotonic trends indicate that modeling HER and other hydrogen-related reactions on under-coordinated sites should also consider the numbers of hydrogen being adsorbed at the same site, otherwise the results could deviate from real experimental situations.
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Reva, I. V., T. T. Yamamoto, A. N. Gulkov, Y. T. Takafudzhi, S. N. Baldaev, K. S. Pikula, M. V. Indyk, et al. "NEUROPROTECTIVE ROLE OF HYDROGEN PEROXIDE." International Journal of Applied and Fundamental Research (Международный журнал прикладных и фундаментальных исследований) 2, no. 12 2018 (2018): 346–52. http://dx.doi.org/10.17513/mjpfi.12537.
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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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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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Sun, Bo, Wenxin Zhang, Yangyang Liu, Min Xue, Lili Qiu, and Zihui Meng. "A Biomass Based Photonic Crystal Hydrogel Made of Bletilla striata Polysaccharide." Biosensors 12, no. 10 (October 8, 2022): 841. http://dx.doi.org/10.3390/bios12100841.
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Bletilla striata is an herb with a good medicinal value whose main active ingredient is Bletilla striata polysaccharide (BSP) in the tuber of Bletilla striata. In this study, a polysaccharide-based semi-interpenetrating network hydrogel was constructed by introducing BSP into polyacrylamide (PAM) hydrogel. The introduction of the BSP chain no only maintains the excellent mechanical properties of PAM, but also endows it with good biocompatibility. By implanting the colloidal crystal array into the above hydrogels, we obtained a novel biomass-based photonic crystal with good stimulus responsiveness that is sensitive to volatile organic compounds (VOCs), especially alcohol vapor. In addition, due to the scavenging ability of BSP to hydroxyl radicals, the photonic crystal hydrogel also has a good response to hydrogen peroxide (H2O2).
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Bai, Shijie, Lin Liu, Chenyang Liu, and Chao Xie. "Phase-Field Insights into Hydrogen Trapping by Secondary Phases in Alloys." Materials 16, no. 8 (April 18, 2023): 3189. http://dx.doi.org/10.3390/ma16083189.
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Solid-state hydrogen storage is the best choice for balancing economy and safety among various hydrogen storage technologies, and hydrogen storage in the secondary phase might be a promising solid-state hydrogen storage scheme. In the current study, to unmask its physical mechanisms and details, a thermodynamically consistent phase-field framework is built for the first time to model hydrogen trapping, enrichment, and storage in the secondary phases of alloys. The hydrogen trapping processes, together with hydrogen charging, are numerically simulated using the implicit iterative algorithm of the self-defined finite elements. Some important results are attained: 1. Hydrogen can overcome the energy barrier under the assistance of the local elastic driving force and then spontaneously enter the trap site from the lattice site. The high binding energy makes it difficult for the trapped hydrogens to escape. 2. The secondary phase geometry stress concentration significantly induces the hydrogen to overcome the energy barrier. 3. The manipulation of the geometry, volume fraction, dimension, and type of the secondary phases is capable of dictating the tradeoff between the hydrogen storage capacity and the hydrogen charging rate. The new hydrogen storage scheme, together with the material design ideology, promises a viable path toward the optimization of critical hydrogen storage and transport for the hydrogen economy.
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He, Tianjiao, Guolin Tong, Penghui Li, Chen Miao, Xin Zhang, and Xuewen Xu. "Effect of nano precipitated calcium carbonate on the properties of hydrogels prepared with acrylamide, starch, and TEMPO-oxidized nanocellulose." BioResources 17, no. 3 (July 14, 2022): 5079–94. http://dx.doi.org/10.15376/biores.17.3.5079-5094.
Full textAbstract:
A variety of water-retaining hydrogels possessing macroporous interiors resembling a honeycomb framework were developed by free radical polymerization of acrylamide (AM), starch, and TEMPO-oxidized nanofibrillated cellulose (TONFC) (Poly (AM-co-TONFC/Starch) (PATS) hydrogels). With the help of ultrasound, nano precipitated calcium carbonate (NPCC) was gelatinized in the preformed NPCC suspension in a monomer solution that forms a hydrogel. When NPCC was dispersed in water, its surface was positively charged, and NPCC could be used as a condensation center to form hydrogen bonds with AM, TONFC, and starch, shortening the distance between AM, TONFC, and starch, increasing the pore size, and thinning the pore wall. The uniform dispersion of NPCC in hydrogels could also promote a more uniform degree of cross-linking in hydrogels. When the hydrogels was extruded and deformed by external forces, the stress of hydrogels was more uniform, so that they could withstand more forces without collapsing. When 4% NPCC was added (relative to starch and TONFC), the pore size of PATS2 hydrogel was uniformly distributed in the range of 10 to 20 μm. The maximum tensile strength of PATS2 hydrogel reached 84.8 KPa, and the elongation at break was 399%. The water absorption reached 172.3, and 65% water content was maintained after 720 h.
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Borgschulte, Andreas, Jasmin Terreni, Emanuel Billeter, Luke Daemen, Yongqiang Cheng, Anup Pandey, Zbigniew Łodziana, Russell J. Hemley, and Anibal J. Ramirez-Cuesta. "Inelastic neutron scattering evidence for anomalous H–H distances in metal hydrides." Proceedings of the National Academy of Sciences 117, no. 8 (February 6, 2020): 4021–26. http://dx.doi.org/10.1073/pnas.1912900117.
Full textAbstract:
Hydrogen-containing materials are of fundamental as well as technological interest. An outstanding question for both is the amount of hydrogen that can be incorporated in such materials, because that determines dramatically their physical properties such as electronic and crystalline structure. The number of hydrogen atoms in a metal is controlled by the interaction of hydrogens with the metal and by the hydrogen–hydrogen interactions. It is well established that the minimal possible hydrogen–hydrogen distances in conventional metal hydrides are around 2.1 Å under ambient conditions, although closer H–H distances are possible for materials under high pressure. We present inelastic neutron scattering measurements on hydrogen in ZrV2Hx showing nonexpected scattering at low-energy transfer. The analysis of the spectra reveals that these spectral features in part originate from hydrogen vibrations confined by neighboring hydrogen at distances as short as 1.6 Å. These distances are much smaller than those found in related hydrides, thereby violating the so-called Switendick criterion. The results have implications for the design and creation of hydrides with additional properties and applications.
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Elvitigala, Kelum Chamara Manoj Lakmal, Wildan Mubarok, and Shinji Sakai. "Human Umbilical Vein Endothelial Cells Form a Network on a Hyaluronic Acid/Gelatin Composite Hydrogel Moderately Crosslinked and Degraded by Hydrogen Peroxide." Polymers 14, no. 22 (November 20, 2022): 5034. http://dx.doi.org/10.3390/polym14225034.
Full textAbstract:
The study of the capillary-like network formation of human umbilical vein endothelial cells (HUVECs) in vitro is important for understanding the factors that promote or inhibit angiogenesis. Here, we report the behavior of HUVECs on the composite hydrogels containing hyaluronic acid (HA) and gelatin with different degrees of degradation, inducing the different physicochemical properties of the hydrogels. The hydrogels were obtained through horseradish peroxidase (HRP)-catalyzed hydrogelation consuming hydrogen peroxide (H2O2, 16 ppm) supplied from the air, and the degradation degree was tuned by altering the exposure time to the air. The HUVECs on the composite hydrogel with intermediate stiffness (1.2 kPa) obtained through 120 min of the exposure were more elongated than those on the soft (0.4 kPa) and the stiff (2.4 kPa) composite hydrogels obtained through 15 min and 60 min of the exposure, respectively. In addition, HUVECs formed a capillary-like network only on the stiff composite hydrogel although those on the hydrogels with comparable stiffness but containing gelatin alone or alginate instead of HA did not form the network. These results show that the HA/gelatin composite hydrogels obtained through the H2O2-mediated crosslinking and degradation could be a tool for studies using HUVECs to understand the promotion and inhibition of angiogenesis.
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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.
Full textAbstract:
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.