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He, Chubin, Xiuru Xu, Yang Lin, Yang Cui und Zhengchun Peng. „A Bilayer Skin-Inspired Hydrogel with Strong Bonding Interface“. Nanomaterials 12, Nr. 7 (29.03.2022): 1137. http://dx.doi.org/10.3390/nano12071137.
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Conductive hydrogels are widely used in sports monitoring, healthcare, energy storage, and other fields, due to their excellent physical and chemical properties. However, synthesizing a hydrogel with synergistically good mechanical and electrical properties is still challenging. Current fabrication strategies are mainly focused on the polymerization of hydrogels with a single component, with less emphasis on combining and matching different conductive hydrogels. Inspired by the gradient modulus structures of the human skin, we propose a bilayer structure of conductive hydrogels, composed of a spray-coated poly(3,4-dihydrothieno-1,4-dioxin): poly(styrene sulfonate) (PEDOT:PSS) as the bonding interface, a relatively low modulus hydrogel on the top, and a relatively high modulus hydrogel on the bottom. The spray-coated PEDOT:PSS constructs an interlocking interface between the top and bottom hydrogels. Compared to the single layer counterparts, both the mechanical and electrical properties were significantly improved. The as-prepared hydrogel showed outstanding stretchability (1763.85 ± 161.66%), quite high toughness (9.27 ± 0.49 MJ/m3), good tensile strength (0.92 ± 0.08 MPa), and decent elastic modulus (69.16 ± 8.02 kPa). A stretchable strain sensor based on the proposed hydrogel shows good conductivity (1.76 S/m), high sensitivity (a maximum gauge factor of 18.14), and a wide response range (0–1869%). Benefitting from the modulus matching between the two layers of the hydrogels, the interfacial interlocking network, and the patch effect of the PEDOT:PSS, the strain sensor exhibits excellent interface robustness with stable performance (>12,500 cycles). These results indicate that the proposed bilayer conductive hydrogel is a promising material for stretchable electronics, soft robots, and next-generation wearables.
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Lim, Chanhyuk, Yongseok Joseph Hong, Jaebong Jung, Yoonsoo Shin, Sung-Hyuk Sunwoo, Seungmin Baik, Ok Kyu Park et al. „Tissue-like skin-device interface for wearable bioelectronics by using ultrasoft, mass-permeable, and low-impedance hydrogels“. Science Advances 7, Nr. 19 (Mai 2021): eabd3716. http://dx.doi.org/10.1126/sciadv.abd3716.
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Hydrogels consist of a cross-linked porous polymer network and water molecules occupying the interspace between the polymer chains. Therefore, hydrogels are soft and moisturized, with mechanical structures and physical properties similar to those of human tissue. Such hydrogels have a potential to turn the microscale gap between wearable devices and human skin into a tissue-like space. Here, we present material and device strategies to form a tissue-like, quasi-solid interface between wearable bioelectronics and human skin. The key material is an ultrathin type of functionalized hydrogel that shows unusual features of high mass-permeability and low impedance. The functionalized hydrogel acted as a liquid electrolyte on the skin and formed an extremely conformal and low-impedance interface for wearable electrochemical biosensors and electrical stimulators. Furthermore, its porous structure and ultrathin thickness facilitated the efficient transport of target molecules through the interface. Therefore, this functionalized hydrogel can maximize the performance of various wearable bioelectronics.
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Michel, Raphaël, Léna Poirier, Quentin van Poelvoorde, Josette Legagneux, Mathieu Manassero und Laurent Corté. „Interfacial fluid transport is a key to hydrogel bioadhesion“. Proceedings of the National Academy of Sciences 116, Nr. 3 (02.01.2019): 738–43. http://dx.doi.org/10.1073/pnas.1813208116.
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Attaching hydrogels to soft internal tissues is a key to the development of a number of biomedical devices. Nevertheless, the wet nature of hydrogels and tissues renders this adhesion most difficult to achieve and control. Here, we show that the transport of fluids across hydrogel−tissue interfaces plays a central role in adhesion. Using ex vivo peeling experiments on porcine liver, we characterized the adhesion between model hydrogel membranes and the liver capsule and parenchyma. By varying the contact time, the tissue hydration, and the swelling ratio of the hydrogel membrane, a transition between two peeling regimes is found: a lubricated regime where a liquid layer wets the interface, yielding low adhesion energies (0.1 J/m2 to 1 J/m2), and an adhesive regime with a solid binding between hydrogel and tissues and higher adhesion energies (1 J/m2 to 10 J/m2). We show that this transition corresponds to a draining of the interface inducing a local dehydration of the tissues, which become intrinsically adhesive. A simple model taking into account the microanatomy of tissues captures the transition for both the liver capsule and parenchyma. In vivo experiments demonstrate that this effect still holds on actively hydrated tissues like the liver capsule and show that adhesion can be strongly enhanced when using superabsorbent hydrogel meshes. These results shed light on the design of predictive bioadhesion tests as well as on the development of improved bioadhesive strategies exploiting interfacial fluid transport.
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Zhao, Wenyu, Zhuofan Lin, Xiaopu Wang, Ziya Wang und Zhenglong Sun. „Mechanically Interlocked Hydrogel–Elastomer Strain Sensor with Robust Interface and Enhanced Water—Retention Capacity“. Gels 8, Nr. 10 (30.09.2022): 625. http://dx.doi.org/10.3390/gels8100625.
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Hydrogels are stretchable ion conductors that can be used as strain sensors by transmitting strain-dependent electrical signals. However, hydrogels are susceptible to dehydration in the air, leading to a loss of flexibility and functions. Here, a simple and general strategy for encapsulating hydrogel with hydrophobic elastomer is proposed to realize excellent water-retention capacity. Elastomers, such as polydimethylsiloxanes (PDMS), whose hydrophobicity and dense crosslinking network can act as a barrier against water evaporation (lost 4.6 wt.% ± 0.57 in 24 h, 28 °C, and ≈30% humidity). To achieve strong adhesion between the hydrogel and elastomer, a porous structured thermoplastic polyurethane (TPU) is used at the hydrogel-elastomer interface to interlock the hydrogel and bond the elastomer simultaneously (the maximum interfacial toughness is over 1200 J/m2). In addition, a PDMS encapsulated ionic hydrogel strain sensor is proposed, demonstrating an excellent water-retention ability, superior mechanical performance, highly linear sensitivity (gauge factor = 2.21, at 100% strain), and robust interface. Various human motions were monitored, proving the effectiveness and practicability of the hydrogel-elastomer hybrid.
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Chen, Jing, Jingli Yang, Guorong Gao und Jun Fu. „Responsive Bilayered Hydrogel Actuators Assembled by Supramolecular Recognition“. MRS Advances 3, Nr. 28 (2018): 1583–88. http://dx.doi.org/10.1557/adv.2018.222.
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ABSTRACTMacroscopic assembling of responsive hydrogels has been used to construct soft actuators that transform their shape upon external stimuli. It remains a challenge to establish a robust assembling interface between gels. Here, we demonstrate a fabrication of bilayered hydrogel actuators assembled by host-guest recognition at the interface. The supramolecular recognition enabled efficient, rapid, and robust macroscopic assembling of hydrogels, which was utilized to create gel bilayers that were actuated upon unbalanced swelling/deswelling.
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Shay, Tim, Orlin D. Velev und Michael D. Dickey. „Soft electrodes combining hydrogel and liquid metal“. Soft Matter 14, Nr. 17 (2018): 3296–303. http://dx.doi.org/10.1039/c8sm00337h.
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Liquid metals interfaced with hydrogels create soft, deformable electrodes for emerging wearable devices and soft robotics. This paper quantifies and tunes the impedance of this interface for use in ECG electrodes.
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Zhao, Xinyi, Bilal Javed, Furong Tian und Kangze Liu. „Hydrogel on a Smart Nanomaterial Interface to Carry Therapeutics for Digitalized Glioma Treatment“. Gels 8, Nr. 10 (17.10.2022): 664. http://dx.doi.org/10.3390/gels8100664.
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Glioma is considered the primary brain tumor to cause brain illnesses, and it is difficult to treat and shows resistance to various routine therapeutics. The most common treatments to cure glioma are the surgical removal of tumors followed by adjuvant chemotherapy and radiation therapy. The latest biocompatible interfaces have been incorporated into therapeutic modalities such as the targeted delivery of drugs using hydrogels to treat and manage brain glioma. This review illustrates the applications of the multimodal hydrogel as the carrier of therapeutics, gene therapy, therapeutic tactics, and glioma devices. The scientific articles were retrieved from 2019 to 2022 on Google Scholar and the Scopus database and screened to determine whether they were suitable for review. The 20 articles that fit the study are summarized in this review. These studies indicated that the sizes of the hydrogel range from 28 nm to 500 nm. There are 16 out of 20 articles that also explain the post-surgical application of hydrogels, and 13 out of 20 articles are employed in 3D culture and other structural manifestations of hydrogels. The pros of the hydrogel include the quick formulation for a sufficient filling of irregular damage sites, solubilizing hydrophobic drugs, continuously slowing drug release, provision of a 3D cell growth environment, improving efficacy, targetability of soluble biomolecules, increasing patient compliance, and decreased side effects. The cons of the hydrogel include difficult real-time monitoring, genetic manipulations, the cumbersome synchronized release of components, and lack of safety data. The prospects of the hydrogel may include the development of electronic hydrogel sensors that can be used to enhance guidance for the precise targeting patterns using patient-specific pathological idiosyncrasies. This technology has the potential to revolutionize the precision medicine approaches that would aid in the early detection and management of solid brain tumors.
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Lin, Yue-Xian, Shu-Han Li und Wei-Chen Huang. „Fabrication of Soft Tissue Scaffold-Mimicked Microelectrode Arrays Using Enzyme-Mediated Transfer Printing“. Micromachines 12, Nr. 9 (31.08.2021): 1057. http://dx.doi.org/10.3390/mi12091057.
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Hydrogels are the ideal materials in the development of implanted bioactive neural interfaces because of the nerve tissue-mimicked physical and biological properties that can enhance neural interfacing compatibility. However, the integration of hydrogels and rigid/dehydrated electronic microstructure is challenging due to the non-reliable interfacial bonding, whereas hydrogels are not compatible with most conditions required for the micromachined fabrication process. Herein, we propose a new enzyme-mediated transfer printing process to design an adhesive biological hydrogel neural interface. The donor substrate was fabricated via photo-crosslinking of gelatin methacryloyl (GelMA) containing various conductive nanoparticles (NPs), including Ag nanowires (NWs), Pt NWs, and PEDOT:PSS, to form a stretchable conductive bioelectrode, called NP-doped GelMA. On the other hand, a receiver substrate composed of microbial transglutaminase-incorporated gelatin (mTG-Gln) enabled simultaneous temporally controlled gelation and covalent bond-enhanced adhesion to achieve one-step transfer printing of the prefabricated NP-doped GelMA features. The integrated hydrogel microelectrode arrays (MEA) were adhesive, and mechanically/structurally bio-compliant with stable conductivity. The devices were structurally stable in moisture to support the growth of neuronal cells. Despite that the introduction of AgNW and PEDOT:PSS NPs in the hydrogels needed further study to avoid cell toxicity, the PtNW-doped GelMA exhibited a comparable live cell density. This Gln-based MEA is expected to be the next-generation bioactive neural interface.
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Gevrek, Tugce Nihal, Aysun Degirmenci, Rana Sanyal und Amitav Sanyal. „Multifunctional and Transformable ‘Clickable’ Hydrogel Coatings on Titanium Surfaces: From Protein Immobilization to Cellular Attachment“. Polymers 12, Nr. 6 (26.05.2020): 1211. http://dx.doi.org/10.3390/polym12061211.
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Multifunctionalizable hydrogel coatings on titanium interfaces are useful in a wide range of biomedical applications utilizing titanium-based materials. In this study, furan-protected maleimide groups containing multi-clickable biocompatible hydrogel layers are fabricated on a titanium surface. Upon thermal treatment, the masked maleimide groups within the hydrogel are converted to thiol-reactive maleimide groups. The thiol-reactive maleimide group allows facile functionalization of these hydrogels through the thiol-maleimide nucleophilic addition and Diels–Alder cycloaddition reactions, under mild conditions. Additionally, the strained alkene unit in the furan-protected maleimide moiety undergoes radical thiol-ene reaction, as well as the inverse-electron-demand Diels–Alder reaction with tetrazine containing molecules. Taking advantage of photo-initiated thiol-ene ‘click’ reactions, we demonstrate spatially controlled immobilization of the fluorescent dye thiol-containing boron dipyrromethene (BODIPY-SH). Lastly, we establish that the extent of functionalization on hydrogels can be controlled by attachment of biotin-benzyl-tetrazine, followed by immobilization of TRITC-labelled ExtrAvidin. Being versatile and practical, we believe that the described multifunctional and transformable ‘clickable’ hydrogels on titanium-based substrates described here can find applications in areas involving modification of the interface with bioactive entities.
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Qiu, Fei, Xiaopeng Fan, Wen Chen, Chunming Xu, Yumei Li und Renjian Xie. „Recent Progress in Hydrogel-Based Synthetic Cartilage: Focus on Lubrication and Load-Bearing Capacities“. Gels 9, Nr. 2 (08.02.2023): 144. http://dx.doi.org/10.3390/gels9020144.
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Articular cartilage (AC), which covers the ends of bones in joints, particularly the knee joints, provides a robust interface to maintain frictionless movement during daily life due to its remarkable lubricating and load-bearing capacities. However, osteoarthritis (OA), characterized by the progressive degradation of AC, compromises the properties of AC and thus leads to frayed and rough interfaces between the bones, which subsequently accelerates the progression of OA. Hydrogels, composed of highly hydrated and interconnected polymer chains, are potential candidates for AC replacement due to their physical and chemical properties being similar to those of AC. In this review, we summarize the recent progress of hydrogel-based synthetic cartilage, or cartilage-like hydrogels, with a particular focus on their lubrication and load-bearing properties. The different formulations, current limitations, and challenges of such hydrogels are also discussed. Moreover, we discuss the future directions of hydrogel-based synthetic cartilage to repair and even regenerate the damaged AC.
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Li, Peiyun, Wenxi Sun, Jiulong Li, Ju-Peng Chen, Xinyue Wang, Zi Mei, Guanyu Jin et al. „N-type semiconducting hydrogel“. Science 384, Nr. 6695 (03.05.2024): 557–63. http://dx.doi.org/10.1126/science.adj4397.
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Hydrogels are an attractive category of biointerfacing materials with adjustable mechanical properties, diverse biochemical functions, and good ionic conductivity. Despite these advantages, their application in electronics has been restricted because of their lack of semiconducting properties, and they have traditionally only served as insulators or conductors. We developed single- and multiple-network hydrogels based on a water-soluble n-type semiconducting polymer, endowing conventional hydrogels with semiconducting capabilities. These hydrogels show good electron mobilities and high on/off ratios, enabling the fabrication of complementary logic circuits and signal amplifiers with low power consumption and high gains. We demonstrate that hydrogel electronics with good bioadhesive and biocompatible interface can sense and amplify electrophysiological signals with enhanced signal-to-noise ratios.
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Liu, Junjie, Nan Hu, Yao Xie, Peng Wang, Jingxiang Chen und Qianhua Kan. „Polyacrylic Acid Hydrogel Coating for Underwater Adhesion: Preparation and Characterization“. Gels 9, Nr. 8 (29.07.2023): 616. http://dx.doi.org/10.3390/gels9080616.
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Underwater adhesion involves bonding substrates in aqueous environments or wet surfaces, with applications in wound dressing, underwater repairs, and underwater soft robotics. In this study, we investigate the underwater adhesion properties of a polyacrylic acid hydrogel coated substrate. The underwater adhesion is facilitated through hydrogen bonds formed at the interface. Our experimental results, obtained through probe-pull tests, demonstrate that the underwater adhesion is rapid and remains unaffected by contact pressure and pH levels ranging from 2.5 to 7.0. However, it shows a slight increase with a larger adhesion area. Additionally, we simulate the debonding process and observe that the high-stress region originates from the outermost bonding region and propagates towards the center, spanning the thickness of the target substrate. Furthermore, we showcase the potential of using the underwater adhesive hydrogel coating to achieve in-situ underwater bonding between a flexible electronic demonstration device and a hydrogel contact lens. This work highlights the advantages of employing hydrogel coatings in underwater adhesion applications and serves as inspiration for the advancement of underwater adhesive hydrogel coatings capable of interacting with a wide range of substrates through diverse chemical and physical interactions at the interface.
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Tan, Jue, Yu Dong Zheng, Ru Tian, Shi Bo Zhang und Hong Yan Chen. „Interfacial Combination and Mechanical Properties of BC/PVA Multilayer Composite Hydrogels“. Advanced Materials Research 335-336 (September 2011): 116–19. http://dx.doi.org/10.4028/www.scientific.net/amr.335-336.116.
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Bacterial cellulose (BC)/Poly vinyl alcohol (PVA) multilayer composite hydrogels were prepared by freezing and thawing. The mechanical properties of the composite were investigated in this paper with different mass percent of PVA, number of BC layers. Scanning electron microscope (SEM) was used to characterize the fracture characterizations of the composite and the interface structure between BC membrane and PVA hydrogel. It was found that composite hydrogels with 15wt% PVA and 2 layers BC membranes exhibit excellent mechanical properties and wonderful bonding effect of the interface.
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Chin, Che-Lun, Lu-Jan Huang, Zheng-Xian Lu, Wei-Chun Weng und Ling Chao. „Using the Water Absorption Ability of Dried Hydrogels to Form Hydrogel-Supported Lipid Bilayers“. Gels 9, Nr. 9 (15.09.2023): 751. http://dx.doi.org/10.3390/gels9090751.
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The formation of supported lipid bilayers (SLBs) on hydrogels can act as a biocompatible anti-fouling interface. However, generating continuous and mobile SLBs on materials other than conventional glass or mica remains a significant challenge. The interaction between lipid membrane vesicles and a typical hydrogel is usually insufficient to induce membrane vesicle rupture and form a planar lipid membrane. In this study, we demonstrate that the water absorption ability of a dried polyacrylamide (PAAm) hydrogel could serve as a driving force to facilitate the formation of the hydrogel–SLBs. The absorption driving force vanishes after the hydrogels are fully hydrated, leaving no extra interaction hindering lipid lateral mobility in the formed SLBs. Our fluorescence recovery after photobleaching (FRAP) results show that SLBs only form on hydrogels with adequate absorption abilities. Moreover, we discovered that exposure to oxygen during drying could lead to the formation of an oxidized crust on the PAAm hydrogel surface, impeding SLB formation. Therefore, minimizing oxygen exposure during drying is crucial to achieving high-quality hydrogel surfaces for SLB formation. This water absorption method enables the straightforward fabrication of hydrogel–SLBs without the need for additional substrates or charges, thereby expanding their potential applications.
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Yang, Renhao, Gen Li, Chengyu Zhuang, Pei Yu, Tingjun Ye, Yin Zhang, Peiyang Shang et al. „Gradient bimetallic ion–based hydrogels for tissue microstructure reconstruction of tendon-to-bone insertion“. Science Advances 7, Nr. 26 (Juni 2021): eabg3816. http://dx.doi.org/10.1126/sciadv.abg3816.
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Although gradients play an essential role in guiding the function of tissues, achieving synchronous regeneration of gradient tissue injuries remains a challenge. Here, a gradient bimetallic (Cu and Zn) ion–based hydrogel was first constructed via the one-step coordinative crosslinking of sulfhydryl groups with copper and zinc ions for the microstructure reconstruction of the tendon-to-bone insertion. In this bimetallic hydrogel system, zinc and copper ions could not only act as crosslinkers but also provide strong antibacterial effects and induce regenerative capacity in vitro. The capability of hydrogels in simultaneously promoting tenogenesis and osteogenesis was further verified in a rat rotator cuff tear model. It was found that the Cu/Zn gradient layer could induce considerable collagen and fibrocartilage arrangement and ingrowth at the tendon-to-bone interface. Overall, the gradient bimetallic ion–based hydrogel ensures accessibility and provides opportunities to regenerate inhomogeneous tissue with physiological complexity or interface tissue.
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Jiang, Qixiang, Angelika Menner und Alexander Bismarck. „Emulsion-templated macroporous polymer/polymer composites with switchable stiffness“. Pure and Applied Chemistry 86, Nr. 2 (01.02.2014): 203–13. http://dx.doi.org/10.1515/pac-2014-5001.
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Abstract Emulsion templates containing monomers in both emulsion phases were used to manufacture polystyrene-co-divinylbenzene based polymerized high internal phase emulsions (polyHIPEs) which have been reinforced by poly(methacrylic acid) (polyMAA) and poly(dimethyl aminoethyl methacrylate) (polyDMAEMA). The morphology of the hydrogel-filled polyHIPEs is affected by the hydrogels synthesized in the aqueous emulsion phase. The pore structure of polyMAA-filled polyHIPEs is highly interconnected indicating the formation of a methacrylic acid-co-styrene copolymer at the oil/water interface of the emulsion templates during synthesis. However, polyDMAEMA-filled polyHIPEs are predominately closed celled and the pore walls are covered by grafted hydrogel. The ability of the hydrogel-filled polyHIPEs to absorb water decreased with increasing crosslinking density of the hydrogels. The dry hydrogel reinforced the polyHIPE scaffolds possessed higher elastic moduli and crush strengths than the control polyHIPEs. The reinforcing ability of the dry hydrogels was further enhanced by increasing their degree of crosslinking. However, the reinforcement could be “switched off” simply by hydrating the hydrogels. The switchable mechanical properties of the hydrogel-filled polyHIPEs could potentially be utilized in smart humidity sensor technology.
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Zhang, Sufeng, Amy Jin, Jochen Lennerz, Joshua Korzenik und Carlo Traverso. „POLYMER-BASED INTERFACE TARGETING INFLAMMATION IN ULCERATIVE COLITIS“. Inflammatory Bowel Diseases 30, Supplement_1 (25.01.2024): S4. http://dx.doi.org/10.1093/ibd/izae020.009.
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Abstract A major hurdle in the treatment of inflammatory bowel disease (IBD) is the lack of effective drug carriers that can precisely deliver the required amount of drug to the sites of inflammation. Available therapies have limited efficacy or severe side effects, largely because of the low concentration of active drugs at the disease sites and non-specific systemic absorption of the administered drugs. Drug delivery targeting the sites of intestinal inflammation offers an approach to maximize therapeutic efficacy while minimizing adverse side effects. We focus on developing formulations that can provide improved local drug administration in the treatment of ulcerative colitis (UC), one of the two main types of IBD. Targeting sites of inflammation in the gastrointestinal tract can be achieved using drug delivery systems that exploit pathophysiological features of the inflamed intestine. Our previous study showed preferential adhesion of a negatively charged small-molecule-based hydrogel to the inflamed colon in murine models of colitis and biopsies from UC patients; further, a corticosteroid drug delivered by this hydrogel demonstrated an improved efficacy compared to the drug alone. Based on our previous experience, we expanded the small-molecule-based hydrogel to polymer-based hydrogels for enhanced selective targeting. We designed the material so that it has a strong affinity towards ulcers. Through molecular structure design, we functionalized thermo-responsive poly(N-isopropylacrylamide) (PNIPAM)-based polymers to modulate the physicochemical properties of the materials and compared the resultant polymers’ gelation and adhesion to the inflamed colon in dextran sulfate sodium (DSS)-induced colitis in mice. We showed that both the types of chemical modification and polymer molecular weight affected the adhesion of the resultant hydrogels to the inflamed colon. We further quantified the disease parameters of colitis for individual mice and correlated the colitis parameters with polymers’ adhesion. Our study suggests a new strategy for targeting the inflamed colon through harnessing charge-mediated interaction and thermo-responsiveness of PNIPAM-based polymers. By adhering to the inflamed mucosa, our delivery system has the potential to maintain the drug locally at the active ulcer sites where it is needed, thereby minimizing the adverse effects of drugs on the healthy tissue. The examination of these polymeric hydrogels’ mucosal binding provides a further understanding of interactions between the polymers and the biological interface in colitis. These studies were performed in preclinical models of UC that develop colitis similar to human UC, as a prerequisite for future studies.
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Gupta, Vinit, und Arun K. Singh. „Scaling laws of gelatin hydrogels for steady dynamic friction“. International Journal of Modern Physics B 30, Nr. 26 (12.10.2016): 1650198. http://dx.doi.org/10.1142/s0217979216501988.
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In this article, we use population balance based dynamic friction model for steady sliding to develop scaling laws in the terms of mesh size of gelatin hydrogels. First of all, it is observed in the sliding experiments that shear modulus of gelatin hydrogels depends on sliding velocity. This dependence is more evident in the case of low sliding velocity. Moreover, relaxation time constant of a dangling chain at the sliding interface scales with the same exponent as its stiffness. The scaling law is also developed for chain density and viscous retardation at the sliding interface. It is also established that the Hookean-based dynamic friction model is sufficient to study frictional behaviour of hydrogels. The reason for this observation is attributed to the weak bonding between a gelatin hydrogel and glass interface.
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Suresh, Manikandan, V. S. Santosh K. Kondeti und Peter J. Bruggeman. „Production and diffusion of H2O2 during the interaction of a direct current pulsed atmospheric pressure plasma jet on a hydrogel“. Journal of Physics D: Applied Physics 55, Nr. 18 (04.02.2022): 185201. http://dx.doi.org/10.1088/1361-6463/ac4ec6.
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Abstract The interaction of cold atmospheric pressure plasma jets with hydrogels has been used as a model system to study the interaction of plasmas with tissues. In this study, we analyze the diffusion of reactive oxygen species (in particular H2O2) and quantify the amount of plasma-produced H2O2 species that penetrates into a gelatin hydrogel. We show that the diffusion constant of H2O2 in 10% gelatin hydrogel is similar to its diffusion constant in water and that the production of H2O2 in the hydrogel is significantly less than the production of H2O2 in distilled water for the same plasma operation conditions suggesting that the scavenging of OH radicals at the plasma-gel interface significantly reduces the H2O2 production.
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Klučáková, Martina. „Effect of Chitosan as Active Bio-colloidal Constituent on the Diffusion of Dyes in Agarose Hydrogel“. Gels 9, Nr. 5 (09.05.2023): 395. http://dx.doi.org/10.3390/gels9050395.
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Agarose hydrogel was enriched by chitosan as an active substance for the interactions with dyes. Direct blue 1, Sirius red F3B, and Reactive blue 49 were chosen as representative dyes for the study of the effect of their interaction with chitosan on their diffusion in hydrogel. Effective diffusion coefficients were determined and compared with the value obtained for pure agarose hydrogel. Simultaneously, sorption experiments were realized. The sorption ability of enriched hydrogel was several times higher in comparison with pure agarose hydrogel. Determined diffusion coefficients decreased with the addition of chitosan. Their values included the effects of hydrogel pore structure and interactions between chitosan and dyes. Diffusion experiments were realized at pH 3, 7, and 11. The effect of pH on the diffusivity of dyes in pure agarose hydrogel was negligible. Effective diffusion coefficients obtained for hydrogels enriched by chitosan increased gradually with increasing pH value. Electrostatic interactions between amino group of chitosan and sulfonic group of dyes resulted in the formation of zones with a sharp boundary between coloured and transparent hydrogel (mainly at lower pH values). A concentration jump was observed at a given distance from the interface between hydrogel and the donor dye solution.
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Hu, Liang, Zeming Chen und Michael J. Serpe. „Interface assisted synthesis of complex hydrogel particles“. Soft Matter 8, Nr. 39 (2012): 10095. http://dx.doi.org/10.1039/c2sm26403j.
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Shao, Jiao-Jing, Si-Da Wu, Shao-Bo Zhang, Wei Lv, Fang-Yuan Su und Quan-Hong Yang. „Graphene oxide hydrogel at solid/liquid interface“. Chemical Communications 47, Nr. 20 (2011): 5771. http://dx.doi.org/10.1039/c1cc11166c.
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Lu, Jiaju, Fengyi Guan, Fuzhai Cui, Xiaodan Sun, Lingyun Zhao, Ying Wang und Xiumei Wang. „Enhanced angiogenesis by the hyaluronic acid hydrogels immobilized with a VEGF mimetic peptide in a traumatic brain injury model in rats“. Regenerative Biomaterials 6, Nr. 6 (05.08.2019): 325–34. http://dx.doi.org/10.1093/rb/rbz027.
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Abstract Angiogenesis plays an important role in brain injury repair, which contributes to the reconstruction of regenerative neurovascular niche for promoting axonal regeneration in the lesion area. As a major component of developing brain extracellular matrix, hyaluronic acid (HA) has attracted more attention as a supporting matrix for brain repair. In the present study, HA-KLT hydrogel was developed via modifying HA with a VEGF mimetic peptide of KLT (KLTWQELYQLKYKGI). The characterization of the hydrogel shows that it could provide a porous, three-dimensional scaffold structure, which has a large specific surface area available for cell adhesion and interaction. Compared with the unmodified HA hydrogel, the HA-KLT hydrogel could effectively promote the attachment, spreading and proliferation of endothelial cells in vitro. Furthermore, the pro-angiogenic ability of hydrogels in vivo was evaluated by implanting them into the lesion cavities in the injured rat brain. Our results showed that the hydrogels could form a permissive interface with the host tissues at 4 weeks after implantation. Moreover, they could efficiently inhibit the formation of glial scars at the injured sites. The HA-KLT hydrogel could significantly increase the expression of endoglin/CD105 and promote the formation of blood vessels, suggesting that HA-KLT hydrogel promoted angiogenesis in vivo. Collectively, the HA-KLT hydrogel has the potential to repair brain defects by promoting angiogenesis and inhibiting the formation of glial-derived scar tissue.
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Klučáková, Martina, Michal Kalina und Vojtěch Enev. „How the Supramolecular Nature of Lignohumate Affects Its Diffusion in Agarose Hydrogel“. Molecules 25, Nr. 24 (10.12.2020): 5831. http://dx.doi.org/10.3390/molecules25245831.
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Lignohumate, as an industrially produced analog of natural humic substances, is studied from the point of view of its diffusion properties. This work focuses on its permeation ability, important in agricultural and horticultural applications, connected with its penetration into plant organs as leaves and roots. The hydrogel based on agarose was used as a model material for the diffusion of lignohumate. Two types of experiments were realized: the diffusion of lignohumate in the hydrogel diffusion couple and the diffusion of lignohumate from its solution into hydrogel. The diffusion coefficient of lignohumate in the hydrogel was determined and used for the modelling of the time development of concentration profiles. It was found that the model agrees with experimental data for short times but an accumulation of lignohumate in front of the interface between donor and acceptor hydrogels was observed after several days. The particle size distribution of lignohumate and changes in the E4/E6 ratio used as an indicator of molecular weight of humic substances were determined. The results showed that the supramolecular structure of lignohumate can react sensitively to actual changes in its environs and thus affect their mobility and permeability into different materials. A filtration effect at the interface can be observed as an accompanying phenomenon of the re-arrangement in the lignohumate secondary structure.
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Sun Han Chang, Raul A., John F. Shanley, Mariana E. Kersh und Brendan A. C. Harley. „Tough and tunable scaffold-hydrogel composite biomaterial for soft-to-hard musculoskeletal tissue interfaces“. Science Advances 6, Nr. 34 (August 2020): eabb6763. http://dx.doi.org/10.1126/sciadv.abb6763.
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Tendon inserts into bone via a fibrocartilaginous interface (enthesis) that reduces mechanical strain and tissue failure. Despite this toughening mechanism, tears occur because of acute (overload) or degradative (aging) processes. Surgically fixating torn tendon into bone results in the formation of a scar tissue interface with inferior biomechanical properties. Progress toward enthesis regeneration requires biomaterial approaches to protect cells from high levels of interfacial strain. We report an innovative tissue reinforcement strategy: a stratified scaffold containing osseous and tendinous tissue compartments attached through a continuous polyethylene glycol (PEG) hydrogel interface. Tuning the gelation kinetics of the hydrogel modulates integration with the flanking compartments and yields biomechanical performance advantages. Notably, the hydrogel interface reduces formation of strain concentrations between tissue compartments in conventional stratified biomaterials that can have deleterious biological effects. This design of mechanically robust stratified composite biomaterials may be appropriate for a broad range of tendon and ligament-to-bone insertions.
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Dragomir, David Catalin, Vlad Carbunaru, Carmen Aura Moldovan, Ioan Lascar, Octavian Dontu, Violeta Ristoiu, Roxana Gheorghe et al. „Biocompatibility Analysis of GelMa Hydrogel and Silastic RTV 9161 Elastomer for Encapsulation of Electronic Devices for Subdermal Implantable Devices“. Coatings 13, Nr. 1 (22.12.2022): 19. http://dx.doi.org/10.3390/coatings13010019.
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The natural differences between human-made electronics and biological tissues constitute a huge challenge in materials and the manufacturing of next-generation bioelectronics. As such, we performed a series of consecutive experiments for testing the biofunctionality and biocompatibility for device implantation, by changing the exterior chemical and physical properties of electronics coating it with silicone or hydrogels. In this article, we present a comparison of the main characteristics of an electronic device coated with either silicone or hydrogel (GelMa). The coating was performed with a bioprinter for accurate silicone and hydrogel deposition around different electronic chips (Step-Down Voltage Regulator U3V15F5 from Pololu Corporation). The results demonstrate that the hydrogel coating presents an augmented biomechanical and biochemical interface and superior biocompatibility, lowers foreign body response, and considerably extends the capabilities for bioelectronic applications.
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Yang, Xin, Bronwin Dargaville und Dietmar Hutmacher. „Elucidating the Molecular Mechanisms for the Interaction of Water with Polyethylene Glycol-Based Hydrogels: Influence of Ionic Strength and Gel Network Structure“. Polymers 13, Nr. 6 (10.03.2021): 845. http://dx.doi.org/10.3390/polym13060845.
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The interaction of water within synthetic and natural hydrogel systems is of fundamental importance in biomaterial science. A systematic study is presented on the swelling behavior and states of water for a polyethylene glycol-diacrylate (PEGDA)-based model neutral hydrogel system that goes beyond previous studies reported in the literature. Hydrogels with different network structures are crosslinked and swollen in different combinations of water and phosphate-buffered saline (PBS). Network variables, polyethylene glycol (PEG) molecular weight (MW), and weight fraction are positively correlated with swelling ratio, while “non-freezable bound water” content decreases with PEG MW. The presence of ions has the greatest influence on equilibrium water and “freezable” and “non-freezable” water, with all hydrogel formulations showing a decreased swelling ratio and increased bound water as ionic strength increases. Similarly, the number of “non-freezable bound water” molecules, calculated from DSC data, is greatest—up to six molecules per PEG repeat unit—for gels swollen in PBS. Fundamentally, the balance of osmotic pressure and non-covalent bonding is a major factor within the molecular structure of the hydrogel system. The proposed model explains the dynamic interaction of water within hydrogels in an osmotic environment. This study will point toward a better understanding of the molecular nature of the water interface in hydrogels.
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Chou, Hsiao-Ying, Chang-Chih Weng, Juin-Yih Lai, Shuian-Yin Lin und Hsieh-Chih Tsai. „Design of an Interpenetrating Polymeric Network Hydrogel Made of Calcium-Alginate from a Thermos-Sensitive Pluronic Template as a Thermal-Ionic Reversible Wound Dressing“. Polymers 12, Nr. 9 (18.09.2020): 2138. http://dx.doi.org/10.3390/polym12092138.
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Polymer-based hydrogels demonstrate superior performance when used as wound dressing. An ideal dressing should possess an active healing function, absorb wound exudates, and provide a moist interface on the wound for rapid injury repair and the prevention of pain and injury during replacement of the dressing. Thus, the aim of this study was to develop a novel, reversible, smart, interpenetrating polymeric network (IPN) by utilizing the thermosensitive network of pluronic F127 (PF127) as a template to regulate the conformation of calcium-ion-crosslinked alginate. We found that the IPN hydrogels formed soft and elastic thermosensitive networks, retaining their form even after absorbing a large amount of wound exudate. The exterior of the hydrogels was made up of a rigid calcium alginate network that supported the entire hydrogel, promoting the stability of the vascular endothelial growth factor (VEGF) payload and controlling its release when the hydrogel was applied topically to wounds. Raman spectroscopy confirmed the layered structure of the hydrogel, which was found to easily disintegrate even after moderate rinsing of the wound with cold phosphate-buffered saline. Taken together, these results show that the IPN hydrogel developed in this study could be a promising delivery platform for growth factors to accelerate wound healing.
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Liu, Hsia-Wei, Chih-Hwa Chen, Ching-Lin Tsai, Chung-Ming Yu, I.-Hsuan Lin und Ging-Ho Hsiue. „ENCAPSULATION OF PERIOSTEAL STEM CELLS IN INJECTABLE PHOTOPOLYMERIZED HYDROGEL ENHANCES TENDON GRAFT OSTEOINTEGRATION“. Journal of Musculoskeletal Research 10, Nr. 03 (September 2006): 109–20. http://dx.doi.org/10.1142/s0218957706001820.
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Photopolymerized hydrogel based on poly(ethylene glycol) diacrylate (PEGDA) was applied to periosteum-derived periosteal stem cell (PSC) encapsulation and orthopedic tissue engineering. To provide support for cell adhesion, hyaluronic acid (HA) was incorporated into the PEGDA solution prior to photopolymerization. HA can be utilized to mimic the extracellular matrix composition as well as control cell growth and differentiation. In vitro studies have demonstrated its ability to encapsulate PSCs to form bone-like tissue in a photopolymerized hydrogel. Osteointegration of a tendon graft within the bone tunnel is a primary concern when employing tendon grafts for ligament reconstruction. This study presents a novel technique for fabricating injectable hydrogel–photoencapsulated PSCs in a bone tunnel to enhance tendon–bone healing. A total of 21 adult New Zealand white rabbits were used. The long extensor digitorum tendon was transplanted into a bone tunnel of the proximal tibia. The tendon was pulled through a drill hole in the proximal tibia and attached to the medial aspect of the tibia. Hydrogel suspension containing PSCs at a concentration of 20 million/mL was injected into the bone tunnel. Histological examination of the tendon–bone interface and biomechanical testing for maximal pull-out load were evaluated at postoperative weeks 3 and 6. Histological analysis of the tendon–bone interface showed an interface fibrous layer formed by the photoencapsulation of PSCs between the tendon and the bone. This layer became progressive integrated with the tendon–bone surface during the healing process. Biomechanical testing revealed higher maximal pull-out strength in experimental groups with a statistically significant difference at 3 and 6 weeks. These results suggest that photopolymerizable PEGDA and HA hydrogels are promising for tissue-engineered stem cell therapy to enhance tendon–bone healing.
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Dai, Ranran, Hao Zhou, Wei Huang, Chaoyue Li, Cheng Qin, Xiaomin Liu und Zhifeng Pan. „Conductive Hydrogel-Based Electronics for Intelligent Sensing and Smart Controlling“. Journal of Nanoelectronics and Optoelectronics 16, Nr. 5 (01.05.2021): 689–98. http://dx.doi.org/10.1166/jno.2021.3024.
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Soft and flexible materials have recently attracted great attention as a sensing layer in the fields of health monitoring, human-machine interface, internet of things and soft robotics. Owing to its unique merits such as excellent flexibility, outstanding biocompatibility and superb sensitivity, conductive hydrogel can meet the need of soft sensing materials in the fields above. However, nonlinear sensitivities under high strains affect the application in practice. Moreover, the free water in conductive hydrogel will freeze or dry under extreme environment, even slowly evaporating at room temperature. Current innovation researches have demonstrated some advanced measures to improve its shortcomings and fit the applications in special environment. This review provides an overview of current flexible electronics based on conductive hydrogel for intelligent sensing and smart controlling. We sort and introduce the fabrication of conductive hydrogel according to different conductive materials. Furthermore, we focus on three classes of applications, including human-machine interfaces (HMIs), health monitoring and motion detection. At the end of the review, the still unresolved challenges are briefly summarized and novel directions for conductive hydrogel-based electronics are provided.
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Wu, Mengfan, Chuyan Zhang, Fujing Wei, Huifang An, Xiaqing Wang, Dan Li, Haoyu Wang, Kexiong Wen, Qingyu Lin und Yixiang Duan. „A self-assembly based on a hydrogel interface: facile, rapid, and large-scale preparation of colloidal photonic crystals“. Materials Chemistry Frontiers 4, Nr. 8 (2020): 2409–17. http://dx.doi.org/10.1039/d0qm00266f.
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Kang, Kyumin, Hyunjin Jung, Soojung An, Hyoung Won Baac, Mikyung Shin und Donghee Son. „Skin-like Transparent Polymer-Hydrogel Hybrid Pressure Sensor with Pyramid Microstructures“. Polymers 13, Nr. 19 (25.09.2021): 3272. http://dx.doi.org/10.3390/polym13193272.
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Soft biomimetic electronic devices primarily comprise an electronic skin (e-skin) capable of implementing various wearable/implantable applications such as soft human–machine interfaces, epidermal healthcare systems, and neuroprosthetics owing to its high mechanical flexibility, tissue conformability, and multifunctionality. The conformal contact of the e-skin with living tissues enables more precise analyses of physiological signals, even in the long term, as compared to rigid electronic devices. In this regard, e-skin can be considered as a promising formfactor for developing highly sensitive and transparent pressure sensors. Specifically, to minimize the modulus mismatch at the biotic–abiotic interface, transparent-conductive hydrogels have been used as electrodes with exceptional pressing durability. However, critical issues such as dehydration and low compatibility with elastomers remain a challenge. In this paper, we propose a skin-like transparent polymer-hydrogel hybrid pressure sensor (HPS) with microstructures based on the polyacrylamide/sodium-alginate hydrogel and p-PVDF-HFP-DBP polymer. The encapsulated HPS achieves conformal contact with skin due to its intrinsically stretchable, highly transparent, widely sensitive, and anti-dehydrative properties. We believe that the HPS is a promising candidate for a robust transparent epidermal stretchable-skin device.
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He, Weizhong, Yajuan Zhu, Yan Chen, Qi Shen, Zhenyu Hua, Xian Wang und Peng Xue. „Inhibitory Effect and Mechanism of Chitosan–Ag Complex Hydrogel on Fungal Disease in Grape“. Molecules 27, Nr. 5 (04.03.2022): 1688. http://dx.doi.org/10.3390/molecules27051688.
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Hydrogel antibacterial agent is an ideal antibacterial material because of its ability to diffuse antibacterial molecules into the decayed area by providing a suitable microenvironment and acting as a protective barrier on the decay interface. The biocompatibility and biodegradation make the removal process easy and it is already widely used in medical fields. However, there have been few reports on its application for controlling postharvest diseases in fruit. In this study, the Chitosan–silver (CS–Ag) complex hydrogels were prepared using the physical crosslinking method, which is used for controlling postharvest diseases in grape. The prepared hydrogels were stable for a long period at room temperature. The structure and surface morphology of CS–Ag composite hydrogels were characterized by UV-Vis, FTIR, SEM, and XRD. The inhibitory effects of CS–Ag hydrogel on disease in grape caused by P. expansum, A. niger, and B. cinerea were investigated both in vivo and in vitro. The remarkable antibacterial activity of CS–Ag hydrogels was mainly due to the combined antibacterial and antioxidant effects of CS and Ag. Preservation tests showed that the CS–Ag hydrogel had positive fresh-keeping effect. This revealed that CS–Ag hydrogels can play a critical role in controlling fungal disease in grapes.
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Zhu, Chenkai, Changyong Huang, Wuxiang Zhang, Xilun Ding und Yang Yang. „Biodegradable-Glass-Fiber Reinforced Hydrogel Composite with Enhanced Mechanical Performance and Cell Proliferation for Potential Cartilage Repair“. International Journal of Molecular Sciences 23, Nr. 15 (05.08.2022): 8717. http://dx.doi.org/10.3390/ijms23158717.
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Polyvinyl alcohol (PVA) hydrogels are promising implants due to the similarity of their low-friction behavior to that of cartilage tissue, and also due to their non-cytotoxicity. However, their poor mechanical resistance and insufficient durability restricts their application in this area. With the development of biodegradable glass fibers (BGF), which show desirable mechanical performance and bioactivity for orthopedic engineering, we designed a novel PVA hydrogel composite reinforced with biodegradable glass fibers, intended for use in artificial cartilage repair with its excellent cytocompatibility and long-term mechanical stability. Using structure characterization and thermal properties analysis, we found hydrogen bonding occurred among PVA molecular networks as well as in the PVA–BGF interface, which explained the increase in crystallinity and glass transition temperature, and was the reason for the improved mechanical performance and better anti-fatigue behavior of the composites in comparison with PVA. The compressive strength and modulus for the PBGF-15 composite reached 3.05 and 3.97 MPa, respectively, equaling the mechanical properties of human articular cartilage. Moreover, the increase in BGF content was found to support the proliferation of chondrocytes in vitro, whilst the PVA hydrogel matrix was able to control the ion concentration by adjusting the ions released from the BGF. Therefore, this novel biodegradable-glass-fiber-reinforced hydrogel composite possesses excellent properties for cartilage repair with potential in medical application.
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Dortdivanlioglu, Berkin, Nil Ezgi Dincer Yilmaz, K. B. Goh, Xiaolin Zheng und Christian Linder. „Swelling-Induced Interface Crease Instabilities at Hydrogel Bilayers“. Journal of Elasticity 145, Nr. 1-2 (20.01.2021): 31–47. http://dx.doi.org/10.1007/s10659-020-09810-8.
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Yang, Quansan, Ziying Hu und John A. Rogers. „Functional Hydrogel Interface Materials for Advanced Bioelectronic Devices“. Accounts of Materials Research 2, Nr. 11 (28.10.2021): 1010–23. http://dx.doi.org/10.1021/accountsmr.1c00142.
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Wen, Yajie, Xiaobin Yang, Yangxue Li, Linlin Yan, Pengzhan Sun und Lu Shao. „Hydrogel/mineral-integrated interface for synergistic antifouling membrane“. Separation and Purification Technology 340 (Juli 2024): 126775. http://dx.doi.org/10.1016/j.seppur.2024.126775.
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Wu, Xiaotong, Ying Liu, Yunlei Zhang, Xingwei Wang, Wufang Yang, Lang Jiang, Shuanhong Ma, Meirong Cai und Feng Zhou. „Interfacial mechanism of hydrogel with controllable thickness for stable drag reduction“. Friction 12, Nr. 2 (29.11.2023): 231–44. http://dx.doi.org/10.1007/s40544-023-0744-z.
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AbstractSurface wettability plays a significant role in reducing solid-liquid frictional resistance, especially the superhydrophilic/hydrophilic interface because of its excellent thermodynamic stability. In this work, poly(acrylic acid)-poly(acrylamide) (PAA–PAM) hydrogel coatings with different thicknesses were prepared in situ by polydopamine (PDA)-UV assisted surface catalytically initiated radical polymerization. Fluid drag reduction performance of hydrogel surface was measured using a rotational rheometer by the plate-plate mode. The experimental results showed that the average drag reduction of hydrogel surface could reach up to about 56% in Couette flow, which was mainly due to the interfacial polymerization phenomenon that enhanced the ability of hydration layer to delay the momentum dissipation between fluid layers and the diffusion behavior of surface. The proposed drag reduction mechanism of hydrogel surface was expected to shed new light on hydrogel-liquid interface interaction and provide a new way for the development of steady-state drag reduction methods.
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Wang, Huiming, und Jianpeng Yang. „Quantifying the equilibrium swelling responses and swelling-induced snap-through of heterogeneous spherical hydrogels“. Journal of Intelligent Material Systems and Structures 32, Nr. 1 (25.08.2020): 113–23. http://dx.doi.org/10.1177/1045389x20951247.
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We employ the finite deformation theory to analyze the inhomogeneous large deformation of a heterogeneous spherical hydrogel subjected to chemo-mechanical loadings. The heterogeneous spherical hydrogel is composed of two concentric spherical hydrogel layers with different material properties. The Gent model is employed for the free energy function of the polymer stretching part in order to tackle the effect of the limiting chain extensibility. The heterogeneous spherical hydrogel is assumed to be perfectly bonded at the interface and is traction free at the external surface. At the internal surface, two boundary conditions are considered: one is internally fixed and the other is internally pressurized. Numerical examples are performed to describe the nonlinear behaviors of a heterogeneous spherical hydrogel when subjected to the swelling and mechanical loadings. For internally fixed case, numerical results show that the limiting chain extensibility and the initial swelling ratio have significant effect on the actuation deformation of a heterogeneous spherical hydrogel. For internally pressurized case, we find that the swelling-induced snap-through instability can be triggered under specified conditions. It is shown that the chemo-mechanical behaviors of the heterogeneous spherical hydrogels can be adjusted by tuning the material properties and the initial swelling ratios.
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Boni, Rossana, und Lynne Regan. „Modulating the Viscoelastic Properties of Covalently Crosslinked Protein Hydrogels“. Gels 9, Nr. 6 (12.06.2023): 481. http://dx.doi.org/10.3390/gels9060481.
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Protein engineering allows for the programming of specific building blocks to form functional and novel materials with customisable physical properties suitable for tailored engineering applications. We have successfully designed and programmed engineered proteins to form covalent molecular networks with defined physical characteristics. Our hydrogel design incorporates the SpyTag (ST) peptide and SpyCatcher (SC) protein that spontaneously form covalent crosslinks upon mixing. This genetically encodable chemistry allowed us to easily incorporate two stiff and rod-like recombinant proteins in the hydrogels and modulate the resulting viscoelastic properties. We demonstrated how differences in the composition of the microscopic building blocks change the macroscopic viscoelastic properties of the hydrogels. We specifically investigated how the identity of the protein pairs, the molar ratio of ST:SC, and the concentration of the proteins influence the viscoelastic response of the hydrogels. By showing tuneable changes in protein hydrogel rheology, we increased the capabilities of synthetic biology to create novel materials, allowing engineering biology to interface with soft matter, tissue engineering, and material science.
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Reynolds, Madelyn, Lindsay M. Stoy, Jindi Sun, Prince Emmanuel Opoku Amponsah, Lin Li, Misael Soto und Shang Song. „Fabrication of Sodium Trimetaphosphate-Based PEDOT:PSS Conductive Hydrogels“. Gels 10, Nr. 2 (01.02.2024): 115. http://dx.doi.org/10.3390/gels10020115.
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Conductive hydrogels are highly attractive for biomedical applications due to their ability to mimic the electrophysiological environment of biological tissues. Although conducting polymer polythiophene-poly-(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonate (PSS) alone exhibit high conductivity, the addition of other chemical compositions could further improve the electrical and mechanical properties of PEDOT:PSS, providing a more promising interface with biological tissues. Here we study the effects of incorporating crosslinking additives, such as glycerol and sodium trimetaphosphate (STMP), in developing interpenetrating PEDOT:PSS-based conductive hydrogels. The addition of glycerol at a low concentration maintained the PEDOT:PSS conductivity with enhanced wettability but decreased the mechanical stiffness. Increasing the concentration of STMP allowed sufficient physical crosslinking with PEDOT:PSS, resulting in improved hydrogel conductivity, wettability, and rheological properties without glycerol. The STMP-based PEDOT:PSS conductive hydrogels also exhibited shear-thinning behaviors, which are potentially favorable for extrusion-based 3D bioprinting applications. We demonstrate an interpenetrating conducting polymer hydrogel with tunable electrical and mechanical properties for cellular interactions and future tissue engineering applications.
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Demirci, Gokhan, Malwina J. Niedźwiedź, Nina Kantor-Malujdy und Miroslawa El Fray. „Elastomer–Hydrogel Systems: From Bio-Inspired Interfaces to Medical Applications“. Polymers 14, Nr. 9 (29.04.2022): 1822. http://dx.doi.org/10.3390/polym14091822.
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Novel advanced biomaterials have recently gained great attention, especially in minimally invasive surgical techniques. By applying sophisticated design and engineering methods, various elastomer–hydrogel systems (EHS) with outstanding performance have been developed in the last decades. These systems composed of elastomers and hydrogels are very attractive due to their high biocompatibility, injectability, controlled porosity and often antimicrobial properties. Moreover, their elastomeric properties and bioadhesiveness are making them suitable for soft tissue engineering. Herein, we present the advances in the current state-of-the-art design principles and strategies for strong interface formation inspired by nature (bio-inspiration), the diverse properties and applications of elastomer–hydrogel systems in different medical fields, in particular, in tissue engineering. The functionalities of these systems, including adhesive properties, injectability, antimicrobial properties and degradability, applicable to tissue engineering will be discussed in a context of future efforts towards the development of advanced biomaterials.
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Smilek, Jiří, Michal Kalina, Marcela Laštůvková, Irena Türkeová, Petr Sedlacek und Martina Klučáková. „Reactivity-Mapping Tool Based on Diffusion Techniques for Characterization of Biocolloids“. Materials Science Forum 851 (April 2016): 130–34. http://dx.doi.org/10.4028/www.scientific.net/msf.851.130.
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The universal reactivity-mapping tool was developed for characterization and study on barrier properties of selected biopolymers. The reactivity of biocolloids (humic acids) was studied by both diffusion techniques (break-through diffusion technique and non-stationary diffusion). The rate of reactivity of humic acids was compared by the interactions with basic cationic organic dye (Methylene Blue) because of the positive interactions among anionic supramolecular humic acids and cationic organic dyes were expected. The reactivity and barrier properties of biocolloids were compared by determination of fundamental diffusion parameters such as effective diffusion coefficient, sorption capacity, break-through time (the time needed for penetration of chosen organic dye through hydrogel porous barrier) or the concentration of organic dye on the interface hydrogel-solution. The original combination of simple diffusion experiments of suitable diffusion probe (organic dye) with the advantages of hydrogel porous media (simple preparation of hydrogels, the diffusion is undisturbed by convection, etc.) provides very valuable information about the reactivity of chosen biocolloids.
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Gao, Xu, Jun-Feng Su, Sai Wang und Peng Yang. „Smart Self-Nourishing and Self-Healing Artificial Skin Composite Using Bionic Microvascular Containing Liquid Agent“. Polymers 14, Nr. 19 (21.09.2022): 3941. http://dx.doi.org/10.3390/polym14193941.
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Artificial skin composites have attracted great interest in functional composite materials. The aim of this study was to prepare and characterize a smart artificial skin composite comprising a bionic microvascular with both self-nourishing and self-healing functions. A poly(vinyl alcohol)–glycerol–gelatin double network organic hydrogel was used as the artificial skin matrix. The hydrogel had high mechanical strength because of the strong hydrogen bond formed between the PVA and glycerol (GL). The gelatin (GEL) increased the toughness and elasticity of the hydrogel to ensure the strength of the artificial skin and fit of the interface with the body. The bionic polyvinylidene fluoride (PVDF) microvascular had excellent thermal stability and mechanical property in artificial skin. Results indicated that self-nourishing was successfully realized by liquid release through the pore structures of the bionic microvascular. The bionic microvascular healed microcracks in the artificial skin when damage occurred, based on a self-healing test.
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Li, Qi, Luochang Wang, Qihan Liu, Wei Hong und Canhui Yang. „Fatigue Damage–Resistant Physical Hydrogel Adhesion“. Frontiers in Robotics and AI 8 (15.04.2021). 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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Liu, Changyi, Kexin Peng, Yilun Wu und Fanfan Fu. „Functional adhesive hydrogels for biological interfaces“. Smart Medicine, 07.10.2023. http://dx.doi.org/10.1002/smmd.20230024.
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AbstractHydrogel adhesives are extensively employed in biological interfaces such as epidermal flexible electronics, tissue engineering, and implanted device. The development of functional hydrogel adhesives is a critical, yet challenging task since combining two or more attributes that seem incompatible into one adhesive hydrogel without sacrificing the hydrogel's pristine capabilities. In this Review, we highlight current developments in the fabrication of functional adhesive hydrogels, which are suitable for a variety of application scenarios, particularly those that occur underwater or on tissue/organ surface conditions. The design strategies for a multifunctional adhesive hydrogel with desirable properties including underwater adhesion, self‐healing, good biocompatibility, electrical conductivity, and anti‐swelling are discussed comprehensively. We then discuss the challenges faced by adhesive hydrogels, as well as their potential applications in biological interfaces. Adhesive hydrogels are the star building blocks of bio‐interface materials for individualized healthcare and other bioengineering areas.
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Yi, Bo, Tianjie Li, Boguang Yang, Sirong Chen, Jianyang Zhao, Pengchao Zhao, Kunyu Zhang, Yi Wang, Zuankai Wang und Liming Bian. „Surface hydrophobization of hydrogels via interface dynamics-induced network reconfiguration“. Nature Communications 15, Nr. 1 (03.01.2024). http://dx.doi.org/10.1038/s41467-023-44646-5.
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AbstractEffective and easy regulation of hydrogel surface properties without changing the overall chemical composition is important for their diverse applications but remains challenging to achieve. We report a generalizable strategy to reconfigure hydrogel surface networks based on hydrogel–substrate interface dynamics for manipulation of hydrogel surface wettability and bioadhesion. We show that the grafting of hydrophobic yet flexible polymeric chains on mold substrates can significantly elevate the content of hydrophobic polymer backbones and reduce the presence of polar groups in hydrogel surface networks, thereby transforming the otherwise hydrophilic hydrogel surface into a hydrophobic surface. Experimental results show that the grafted highly dynamic hydrophobic chains achieved with optimal grafting density, chain length, and chain structure are critical for such substantial hydrogel surface network reconfiguration. Molecular dynamics simulations further reveal the atomistic details of the hydrogel network reconfiguration induced by the dynamic interface interactions. The hydrogels prepared using our strategy show substantially enhanced bioadhesion and transdermal delivery compared with the hydrogels of the same chemical composition but fabricated via the conventional method. Our findings provide important insights into the dynamic hydrogel–substrate interactions and are instrumental to the preparation of hydrogels with custom surface properties.
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Chen, Liangyuan, Tuo Xiao, Jin-Lin Yang, Yipu Liu, Jinglin Xian, Kang Liu, Yan Zhao, Hong Jin Fan und Peihua Yang. „In‐Situ Spontaneous Electropolymerization Enables Robust Hydrogel Electrolyte Interfaces in Aqueous Batteries“. Angewandte Chemie International Edition, 22.03.2024. http://dx.doi.org/10.1002/anie.202400230.
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Hydrogels hold great promise as electrolytes for emerging aqueous batteries, for which establishing a robust electrode‐hydrogel interface is crucial for mitigating side reactions. Conventional hydrogel electrolytes fabricated by ex‐situ polymerization through either thermal stimulation or photo exposure cannot ensure complete interfacial contact with electrodes. Herein, we introduce an in‐situ electropolymerization approach for constructing hydrogel electrolytes. The hydrogel is spontaneously generated during the initial cycling of the battery, eliminating the need of additional initiators for polymerization. The involvement of electrodes during the hydrogel synthesis yields well‐bonded and deep infiltrated electrode‐electrolyte interfaces. As a case study, we attest that, the in‐situ formed polyanionic hydrogel in Zn‐MnO2 battery substantially improves the stability and kinetics of both Zn anode and porous MnO2 cathode owing to the robust interfaces. This research provides insight to the function of hydrogel electrolyte interfaces and constitute a critical advancement in designing highly durable aqueous batteries.
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Chen, Liangyuan, Tuo Xiao, Jin-Lin Yang, Yipu Liu, Jinglin Xian, Kang Liu, Yan Zhao, Hong Jin Fan und Peihua Yang. „In‐Situ Spontaneous Electropolymerization Enables Robust Hydrogel Electrolyte Interfaces in Aqueous Batteries“. Angewandte Chemie, 22.03.2024. http://dx.doi.org/10.1002/ange.202400230.
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Hydrogels hold great promise as electrolytes for emerging aqueous batteries, for which establishing a robust electrode‐hydrogel interface is crucial for mitigating side reactions. Conventional hydrogel electrolytes fabricated by ex‐situ polymerization through either thermal stimulation or photo exposure cannot ensure complete interfacial contact with electrodes. Herein, we introduce an in‐situ electropolymerization approach for constructing hydrogel electrolytes. The hydrogel is spontaneously generated during the initial cycling of the battery, eliminating the need of additional initiators for polymerization. The involvement of electrodes during the hydrogel synthesis yields well‐bonded and deep infiltrated electrode‐electrolyte interfaces. As a case study, we attest that, the in‐situ formed polyanionic hydrogel in Zn‐MnO2 battery substantially improves the stability and kinetics of both Zn anode and porous MnO2 cathode owing to the robust interfaces. This research provides insight to the function of hydrogel electrolyte interfaces and constitute a critical advancement in designing highly durable aqueous batteries.
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Wang, Zibi, Fahu Yang, Xiaoxu Liu, Xiang Han, Xinxin Li, Chenxi Huyan, Dong Liu und Fei Chen. „Hydrogen Bonds‐Pinned Entanglement Blunting The Interfacial Crack of Hydrogel‐Elastomer Hybrids“. Advanced Materials, 25.01.2024. http://dx.doi.org/10.1002/adma.202313177.
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AbstractAnchoring a layer of amorphous hydrogel on an antagonistic elastomer has potential applications in surface aqueous lubrication. However, the interfacial crack propagation usually occurs under continuous loads for amorphous hydrogel, leading to the failure of hydrogel interface. This work presents a universal strategy to blunt the interfacial cracks by designing a hydrogen bonds‐pinned entanglement (Hb‐En) structure of amorphous hydrogel on engineering elastomers. The unique Hb‐En structures is created by pinning well‐tailored entanglements via covalent‐like hydrogen bonds, which can amplify the delocalization of interfacial stress concentration and elevate the necessary fracture energy barrier within hydrogel interface. Therefore, the interfacial crack propagation could be suppressed under single and cyclic loads, resulting in a high interfacial toughness over 1650 J/m2 and an excellent interfacial fatigue threshold of 423 J/m2. Such a strategy universally works on blunting the interfacial crack between hydrogel coating and various elastomer materials with arbitrary shapes. The superb fatigue‐crack insensitivity at the interface allows for durable aqueous lubrication of hydrogel coating with low friction.This article is protected by copyright. All rights reserved