共查询到20条相似文献,搜索用时 31 毫秒
1.
Wet‐Responsive,Reconfigurable, and Biocompatible Hydrogel Adhesive Films for Transfer Printing of Nanomembranes
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hoon Yi Minho Seong Kahyun Sun Insol Hwang Kangseok Lee Chaenyung Cha Tae‐il Kim Hoon Eui Jeong 《Advanced functional materials》2018,28(18)
This study presents a wet‐responsive and biocompatible smart hydrogel adhesive that exhibits switchable and controllable adhesions on demand for the simple and efficient transfer printing of nanomembranes. The prepared hydrogel adhesives show adhesion strength as high as ≈191 kPa with the aid of nano‐ or microstructure arrays on the surface in the dry state. When in contact with water, the nano/microscopic and macroscopic shape reconfigurations of the hydrogel adhesive occur, which turns off the adhesion (≈0.30 kPa) with an extremely high adhesion switching ratio (>640). The superior adhesion behaviors of the hydrogels are maintained over repeating cycles of hydration and dehydration, indicating their ability to be used repeatedly. The adhesives are made of a biocompatible hydrogel and their adhesion on/off can be controlled with water, making the adhesives compatible with various materials and surfaces, including biological substrates. Based on these smart adhesion capabilities, diverse metallic and semiconducting nanomembranes can be transferred from donor substrates to either rigid or flexible surfaces including biological tissues in a reproducible and robust fashion. Transfer printing of a nanoscale crack sensor onto a bovine eye further demonstrates the potential of the reconfigurable hydrogel adhesive for use as a stimuli‐responsive, smart, and versatile functional adhesive for nanotransfer printing. 相似文献
2.
Stimuli‐responsive hydrogels with decent electrical properties are a promising class of polymeric materials for a range of technological applications, such as electrical, electrochemical, and biomedical devices. In this paper, thermally responsive and conductive hybrid hydrogels are synthesized by in situ formation of continuous network of conductive polymer hydrogels crosslinked by phytic acid in poly(N‐isopropylacrylamide) matrix. The interpenetrating binary network structure provides the hybrid hydrogels with continuous transporting path for electrons, highly porous microstructure, strong interactions between two hydrogel networks, thus endowing the hybrid hydrogels with a unique combination of high electrical conductivity (up to 0.8 S m?1), high thermoresponsive sensitivity (significant volume change within several seconds), and greatly enhanced mechanical properties. This work demonstrates that the architecture of the filling phase in the hydrogel matrix and design of hybrid hydrogel structure play an important role in determining the performance of the resulting hybrid material. The attractive performance of these hybrid hydrogels is further demonstrated by the developed switcher device which suggests potential applications in stimuli‐responsive electronic devices. 相似文献
3.
Jun Wu Dequn Wu Martha A. Mutschler Chih‐Chang Chu 《Advanced functional materials》2012,22(18):3815-3823
A family of biodegradable, biocompatible, water soluble cationic polymer precursor, arginine‐based unsaturated poly (ester amide) (Arg‐UPEA), is reported. Its incorporation into conventional Pluronic diacrylate (Pluronic‐DA) to form hybrid hydrogels for a significant improvement of the biological performance of current synthetic hydrogels is shown. The gel fraction (Gf), equilibrium swelling ratio (Qeq), compressive modulus, and interior morphology of the hybrid hydrogels as well as their interactions with human fibroblasts and bovine endothelial cells are fully investigated. It is found that the incorporation of Arg‐UPEA into Pluronic‐DA hydrogels significantly changes their Qeq, mechanical strength, and interior morphology. The structure–property relationship of the newly fabricated hybrid hydrogels is studied in terms of the chemical structure of the Arg‐UPEA precursor, i.e., the number of methylene groups in the Arg‐UPEA repeating unit. The results indicate that increasing methylene groups in the Arg‐UPEA repeating unit increases Qeq and decreases the compressive modulus of hydrogels. When compared with a pure Pluronic hydrogel, the cationic Arg‐UPEAs/Pluronic hybrid hydrogels greatly improve the attachment and proliferation of human fibroblasts on hydrogel surfaces. A bovine aortic endothelial cells (BAEC) viability test in the interior of the hydrogels shows that the positively charged hybrid hydrogels can significantly improve the viability of the encapsulated endothelial cell over a 2 week study period when compared with a pure Pluronic hydrogel. 相似文献
4.
The development of adhesives that can achieve robust and repeatable adhesion to various surfaces underwater is promising; however, this remains a major challenge primarily because the surface hydration layer weakens the interfacial molecular interactions. Herein, a strategy is proposed to develop tough hydrogels that are robust, reusable, and long-lasting for underwater adhesion. Hydrogels from cationic and aromatic monomers with an aromatic-rich composition inspired by the amino acid residuals in barnacle cement proteins are synthesized. The hydrogels are mechanically strong and tough (elastic modulus 0.35 MPa, fracture stress 1.0 MPa, and fracture strain 720%), owing to the interchain π–π and cation–π interactions. In water, the hydrogels firmly adhere to diverse surfaces through interfacial electrostatic and hydrophobic interactions (adhesion strength of 180 kPa), which allows for instant adhesion and reversibility (50 times). Moreover, the hydrogel shows long-lasting adhesion in water for months (100 days). Novel adhesive hydrogels may be useful in many applications, including underwater transfer, water-based devices, underwater repair, and underwater soft robots. 相似文献
5.
Hong Chen Yonglan Liu Baiping Ren Yanxian Zhang Jie Ma Lijian Xu Qiang Chen Jie Zheng 《Advanced functional materials》2017,27(44)
Conventional design wisdom prevents both bulk and interfacial toughness to be presented in the same hydrogel, because the bulk properties of hydrogels are usually different from the interfacial properties of the same hydrogels on solid surfaces. Here, a fully‐physically‐linked agar (the first network)/poly(N ‐hydroxyethyl acrylamide) (pHEAA, the second network), where both networks are physically crosslinked via hydrogen bonds, is designed and synthesized. Bulk agar/pHEAA hydrogels exhibit high mechanical properties (2.6 MPa tensile stress, 8.0 tensile strain, 8000 J m?2 tearing energy, 1.62 MJ m?3 energy dissipation), high self‐recovery without any external stimuli (62%/30% toughness/stiffness recovery), and self‐healing property. More impressively, without any surface modification, agar/pHEAA hydrogels can be easily and physically anchored onto different nonporous solid substrates of glass, titanium, aluminum, and ceramics to produce superadhesive hydrogel–solid interfaces (i.e., high interfacial toughness of 2000–7000 J m?2). Comparison of as‐prepared and swollen gels in water and hydrogen‐bond‐breaking solvents reveals that strong bulk toughness provides a structural basis for strong interfacial toughness, and both high toughness mainly stem from cooperative hydrogen bonds between and within two networks and between two networks and solid substrates. This work demonstrates a new gel system to achieve superhigh bulk and interfacial toughness on nonporous solid surfaces. 相似文献
6.
Hydrogel microstructures with micrometer‐scale topography and controllable functionality have great potential for numerous nanobiotechnology applications including, for example, three‐dimensional structures that exhibit controlled interactions with proteins and cells. Taking advantage of the strong affinity of histidine (His) residues for metal‐ion–nitrilotriacetic acid (NTA) complexes, we have chemically modified hydrogels to enable protein immobilization with retention of activity by incorporating 2‐methacrylamidobutyl nitrilotriacetic acid, an NTA‐containing monomer that can be copolymerized with a series of monomers to form NTA‐containing hydrogels. By varying the NTA‐monomer composition in the hydrogels, it is possible to control the amount of protein bound to the hydrogel surface. The retention of biological activity was demonstrated by microtubule gliding assays. Normally, hydrogels are resistant to protein binding, but we have selected these materials because of their porous nature. Bringing together hydrogel functionalization and soft‐lithography patterning techniques, it was possible to create a hybrid hydrogel superstructure that possesses binding specificity to His‐tagged protein in selected sites. This type of surface and microstructure is not only advantageous for motor protein integration, but it can also be generally applied to the formation of His‐tagged molecules for sensors and biochip applications. 相似文献
7.
Supertough Hybrid Hydrogels Consisting of a Polymer Double‐Network and Mesoporous Silica Microrods for Mechanically Stimulated On‐Demand Drug Delivery
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Suji Choi Young jin Choi Moon‐Sun Jang Jung Hee Lee Ji Hoon Jeong Jaeyun Kim 《Advanced functional materials》2017,27(42)
Despite their potential in various fields of bioapplications, such as drug/cell delivery, tissue engineering, and regenerative medicine, hydrogels have often suffered from their weak mechanical properties, which are attributed to their single network of polymers. Here, supertough composite hydrogels are proposed consisting of alginate/polyacrylamide double‐network hydrogels embedded with mesoporous silica particles (SBA‐15). The supertoughness is derived from efficient energy dissipation through the multiple bondings, such as ionic crosslinking of alginate, covalent crosslinking of polyacrylamide, and van der Waals interactions and hydrogen bondings between SBA‐15 and the polymers. The superior mechanical properties of these hybrid hydrogels make it possible to maintain the hydrogel structure for a long period of time in a physiological solution. Based on their high mechanical stability, these hybrid hydrogels are demonstrated to exhibit on‐demand drug release, which is controlled by an external mechanical stimulation (both in vitro and in vivo). Moreover, different types of drugs can be separately loaded into the hydrogel network and mesopores of SBA‐15 and can be released with different speeds, suggesting that these hydrogels can also be used for multiple drug release. 相似文献
8.
A Biomimetic Mussel‐Inspired ε‐Poly‐l‐lysine Hydrogel with Robust Tissue‐Anchor and Anti‐Infection Capacity
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rui Wang Jingzhe Li Wei Chen Tingting Xu Shifeng Yun Zheng Xu Zongqi Xu Takashi Sato Bo Chi Hong Xu 《Advanced functional materials》2017,27(8)
In situ hydrogels have attracted considerable attention in tissue engineering because of their minimal invasiveness and ability to match the irregular tissue defects. However, hydrous physiological environments and the high level of moisture in hydrogels severely hamper binding to the target tissue and easily cause wound infection, thereby limiting the effectiveness in wound care management. Thus, forming an intimate assembly of the hydrogel to the tissue and preventing wound infecting still remains a significant challenge. In this study, inspired by mussel adhesive protein, a biomimetic dopamine‐modified ε‐poly‐l ‐lysine‐polyethylene glycol‐based hydrogel (PPD hydrogel) wound dressing is developed in situ using horseradish peroxidase cross‐linking. The biomimetic catechol–Lys residue distribution in PPD polymer provides a catechol–Lys cooperation effect, which endows the PPD hydrogels with superior wet tissue adhesion properties. It is demonstrated that the PPD hydrogel can facilely and intimately integrate with biological tissue and exhibits superior capacity of in vivo hemostatic and accelerated wound repair. In addition, the hydrogels exhibit outstanding anti‐infection property because of the inherent antibacterial ability of ε‐poly‐l ‐lysine. These findings shed new light on the development of mussel‐inspired tissue‐anchored and antibacterial hydrogel materials serving as wound dressings. 相似文献
9.
Zhaoxiang Yang Yonglin He Yingchao Ma Li Li Yapei Wang 《Advanced functional materials》2023,33(12):2213150
Due to the existence of hydration layer at interfaces, the weak affinity between hydrogels and most hydrophobic materials routinely generates weak and brittle bonding, which has been a disadvantage of hydrogels when serving as coatings on solid substrates. Herein, a finding of substantial affinity is presented between polyacrylamide-based hydrogels and cellulose acetate (CA) without particular chemical and physical pretreatments. Besides understanding the mechanism behind it, this unusual finding motivates to make reversible adhesive hydrogel tapes. Learning from the commercial Scotch Magic Tape which typically paints a glue layer on polymer films to achieve appropriate adhesion on solid surfaces, the CA backlayer can be easily glued and firmly bonded to arbitrary solid surfaces without affecting the properties of hydrogel layer on the other side. This particular kind of hydrogel tape can be readily scaled up from laboratory synthesis to a roll-to-roll continuous production. Several applications of hydrogel tapes are succeeded in alarming hyperthermia, thermal dissipation, and serving as ultrasonic couplant. In terms of the advantages of low cost, green fabrication, convenient operation, sticky performance and ignorable residues, the hydrogel tape would be one of the desirable choices to be used as one-off healthcare material. 相似文献
10.
Jiankang He Yanan Du José L. Villa‐Uribe Changmo Hwang Dichen Li Ali Khademhosseini 《Advanced functional materials》2010,20(1):131-137
Many biological processes are regulated by gradients of bioactive chemicals. Thus, the generation of materials with embedded chemical gradients may be beneficial for understanding biological phenomena and generating tissue‐mimetic constructs. Here a simple and versatile method to rapidly generate materials containing centimeter‐long gradients of chemical properties in a microfluidic channel is described. The formation of a chemical gradient is initiated by a passive‐pump‐induced forward flow and further developed during an evaporation‐induced backward flow. The gradient is spatially controlled by the backward flow time and the hydrogel material containing the gradient is synthesized via photopolymerization. Gradients of a cell‐adhesion ligand, Arg‐Gly‐Asp‐Ser (RGDS), are incorporated in poly(ethylene glycol)‐diacrylate (PEG‐DA) hydrogels to test the response of endothelial cells. The cells attach and spread along the hydrogel material in a manner consistent with the RGDS‐gradient profile. A hydrogel containing a PEG‐DA concentration gradient and constant RGDS concentration is also shown. The morphology of cells cultured on such hydrogel changes from round in the lower PEG‐DA concentration regions to well‐spread in the higher PEG‐DA concentration regions. This approach is expected to be a valuable tool to investigate the cell–material interactions in a simple and high‐throughput manner and to design graded biomimetic materials for tissue engineering applications. 相似文献
11.
Tobias Ekblad Lars Faxälv Olof Andersson Nanny Wallmark Andréas Larsson Tomas L. Lindahl Bo Liedberg 《Advanced functional materials》2010,20(15):2396-2403
This work describes the preparation and properties of hydrogel surface chemistries enabling controlled and well‐defined cell adhesion. The hydrogels may be prepared directly on plastic substrates, such as polystyrene slides or dishes, using a quick and experimentally simple photopolymerization process, compatible with photolithographic and microfluidic patterning methods. The intended application for these materials is as substrates for diagnostic cell adhesion assays, particularly for the analysis of human platelet function. The non‐specific adsorption of fibrinogen, a platelet adhesion promoting protein, is shown to be completely inhibited by the hydrogel, provided that the film thickness is sufficient (>5 nm). This allows the hydrogel to be used as a matrix for presenting selected bioactive ligands without risking interference from non‐specifically adsorbed platelet adhesion factors, even in undiluted whole blood and blood plasma. This concept is demonstrated by preparing patterns of proteins on hydrogel surfaces, resulting in highly controlled platelet adhesion. Further insights into the protein immobilization and platelet adhesion processes are provided by studies using imaging surface plasmon resonance. The hydrogel surfaces used in this work appear to provide an ideal platform for cell adhesion studies of platelets, and potentially also for other cell types. 相似文献
12.
Versatile strategies are currently being discovered for the fabrication of synthetic polypeptide‐based hybrid hydrogels, which have potential applications in polymer therapeutics and regenerative medicine. Herein, a new concept—the reverse micellar hydrogel—is introduced, and a versatile strategy is provided for fabricating supramolecular polypeptide‐based normal micellar hydrogel and reverse micellar hydrogels from the same polypeptide‐based copolymer via the cooperation of host–guest chemistry and hydrogen‐bonding interactions. The supramolecular hydrogels are thoroughly characterized, and a mechanism for their self‐assembly is proposed. These hydrogels can respond to dual stimuli—temperature and pH—and their mechanical and controlled drug‐release properties can be tuned by the copolymer topology and the polypeptide composition. The reverse micellar hydrogel can load 10% of the anticancer drug doxorubicin hydrochloride (DOX) and sustain DOX release for 45 days, indicating that it could be useful as an injectable drug delivery system. 相似文献
13.
Cong Li Shiyu Feng Caicong Li Yuan Sui Jinghui Shen Chongyu Huang Yonggang Wu Weiguo Huang 《Advanced functional materials》2020,30(32)
A simple yet robust strategy called “‘in situ' transformation” is developed to prepare organo/hydro binary gels based on the aminolysis of poly(pentafluorophenyl acrylate) (pPFPA). Treated with desired hydrophilic, oleophilic alkylamines, and their mixtures, pPFPA‐based organogels can be thoroughly transformed to targeted hydrogels, organogels, and even organohydrogels with outstanding mechanical properties. Further, relying on programed aminolysis procedures, site‐specific “in situ” transformation can be realized, giving rise to organo/hydro binary gels with diverse patterns and morphologies, such as macroscopic layered organo/hydrogel with a smooth‐transitioned yet mechanically robust interface, reconfigurable microscale organo/hydrogel hybrids with a high spatial‐resolution pattern capable of reversibly transforming between 2D sheets and 3D helixes with controlled chirality in different solvents, and core–shell structured organo/hydrogel hybrids with readily adjustable core/shell dimensions, tunable internal stress, and transparency. Finally, an oscillator based on a bilayered organo/hydrogel hybrid is developed. Attributing to the synergistic effect of organogel expansion and hydrogel contraction, as well as the robust interfacial mechanical properties, this oscillator is capable of ultrafast self‐actuating through harvesting surrounding chemical and thermal energy. This work provides new design principles and highly efficient synthetic strategy for organo/hydro binary gels, and expands their potential applications in soft robotics. 相似文献
14.
Yuwei Hu Chun‐Hua Lu Weiwei Guo Miguel Angel Aleman‐Garcia Jiangtao Ren Itamar Willner 《Advanced functional materials》2015,25(44):6867-6874
Shape memory acrylamide/DNA hydrogels include two different crosslinkers as stabilizing elements. The triggered dissociation of one of the crosslinking elements transforms the shaped hydrogel into an arbitrarily shaped (or shapeless) quasi‐liquid state. The remaining crosslinking element, present in the quasi‐liquid, provides an internal memory that restores the original shaped hydrogel upon the stimulus‐triggered regeneration of the second crosslinking element. Two pH‐sensitive shape memory hydrogels, forming Hoogsten‐type triplex DNA structures, are described. In one system, the shaped hydrogel is stabilized at pH = 7.0 by two different duplex crosslinkers, and the transition of the hydrogel into the shapeless quasi‐liquid proceeds at pH = 5.0 by separating one of the crosslinking units into a protonated cytosine–guanine–cytosine (C–G·C+ ) triplex. The second shaped hydrogel is stabilized at pH = 7.0, by cooperative duplex and thymine–adenine–thymine triplex (T–A·T) bridges. At pH = 10.0, the triplex units separate, leading to the dissociation of the hydrogel into the quasi‐liquid state. The cyclic, pH‐stimulated transitions of the two systems between shaped hydrogels and shapeless states are demonstrated. Integrating the two hydrogels into a shaped “two‐arrowhead” hybrid structure allows the pH‐stimulated cyclic transitions of addressable domains of the hybrid between shaped and quasi‐liquid states. 相似文献
15.
Donglin Gan Tong Xu Wensi Xing Xiang Ge Liming Fang Kefeng Wang Fuzeng Ren Xiong Lu 《Advanced functional materials》2019,29(1)
Antibacterial hydrogel has received extensive attention in soft tissue repair, especially preventing infections those associated with impaired wound healing. However, it is challenging in developing an inherent antibacterial hydrogel integrating with excellent cell affinity and superior mechanical properties. Inspired by the mussel adhesion chemistry, a contact‐active antibacterial hydrogel is proposed by copolymerization of methacrylamide dopamine (MADA) and 2‐(dimethylamino)ethyl methacrylate and forming an interpenetrated network with quaternized chitosan. The reactive catechol groups of MADA endow the hydrogel with contact intensified bactericidal activity, because it increases the exposure of bacterial cells to the positively charged groups of the hydrogel and strengthens the bactericidal effect. MADA also maintains the good adhesion of fibroblasts to the hydrogel. Moreover, the hybrid chemical and physical cross‐links inner the hydrogel network makes the hydrogel strong and tough with good recoverability. In vitro and in vivo tests demonstrate that this tough and contact‐active antibacterial hydrogel is a promising material to fulfill the dual functions of promoting tissue regeneration and preventing bacterial infection for wound‐healing applications. 相似文献
16.
Li Zhou Yuewei Xi Yumeng Xue Min Wang Yanle Liu Yi Guo Bo Lei 《Advanced functional materials》2019,29(22)
The surgical procedure in skin‐tumor therapy usually results in cutaneous defects, and multidrug‐resistant bacterial infection could cause chronic wounds. Here, for the first time, an injectable self‐healing antibacterial bioactive polypeptide‐based hybrid nanosystem is developed for treating multidrug resistant infection, skin‐tumor therapy, and wound healing. The multifunctional hydrogel is successfully prepared through incorporating monodispersed polydopamine functionalized bioactive glass nanoparticles (BGN@PDA) into an antibacterial F127‐ε‐Poly‐L‐lysine hydrogel. The nanocomposites hydrogel displays excellent self‐healing and injectable ability, as well as robust antibacterial activity, especially against multidrug‐resistant bacteria in vitro and in vivo. The nanocomposites hydrogel also demonstrates outstanding photothermal performance with (near‐infrared laser irradiation) NIR irradiation, which could effectively kill the tumor cell (>90%) and inhibit tumor growth (inhibition rate up to 94%) in a subcutaneous skin‐tumor model. In addition, the nanocomposites hydrogel effectively accelerates wound healing in vivo. These results suggest that the BGN‐based nanocomposite hydrogel is a promising candidate for skin‐tumor therapy, wound healing, and anti‐infection. This work may offer a facile strategy to prepare multifunctional bioactive hydrogels for simultaneous tumor therapy, tissue regeneration, and anti‐infection. 相似文献
17.
Ultracompliant Hydrogel‐Based Neural Interfaces Fabricated by Aqueous‐Phase Microtransfer Printing
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wei‐Chen Huang Xiao Chuan Ong Ik Soo Kwon Chaitanya Gopinath Lee E. Fisher Haosheng Wu Gary K. Fedder Robert A. Gaunt Christopher J. Bettinger 《Advanced functional materials》2018,28(29)
Hydrogel‐based electronics are ideally suited for neural interfaces because they exhibit ultracompliant mechanical properties that match that of excitable tissue in the brain and peripheral nerve. Hydrogel‐based multielectrode arrays (MEAs) can conformably interface with tissues to minimize inflammation and improve the reliability to enhance signal transduction. However, MEA substrates composed of swollen hydrogels exhibit low toughness and poor adhesion when laminated on the tissue surface and also present incompatibilities with processes commonly used in MEA fabrication. Here, a strategy to fabricate an ultracompliant MEA is described based on aqueous‐phase transfer printing. This technique employs redox active adhesive motifs in hygroscopic polymer precursors that simultaneously form hydrogels through sol–gel phase transitions and bond to materials in the underlying microelectronic structures. Specifically, in situ gelation of four‐arm‐polyethylene glycol‐grafted catechol [PEG‐Dopa]4 hydrogels induced by oxidation using Fe3+ produces conformal adhesive contact with the underlying MEA, robust adhesion to electronic sub‐structures, and rapid dissolution of water‐soluble sacrificial release layers. MEAs are integrated on hydrogel‐based substrates to produce free‐standing ultracompliant neural probes, which are then laminated to the surface of the dorsal root ganglia in feline subjects to record single‐unit neural activity. 相似文献
18.
Lei Wang Xuehui Zhang Kun Yang Yu Vincent Fu Tianshun Xu Shengliang Li Dawei Zhang Lu‐Ning Wang Chun‐Sing Lee 《Advanced functional materials》2020,30(1)
Most photocrosslinkable hydrogels have inadequacy in either mechanical performance or biodegradability. This issue is addressed by adopting a novel hydrogel design by introducing two different chitosan chains (catechol‐modified methacryloyl chitosan, CMC; methacryloyl chitosan, MC) via the simultaneous crosslinking of carbon–carbon double bonds and catechol‐Fe3+ chelation. This leads to an interpenetrating network of two chitosan chains with high crosslinking‐network density, which enhances mechanical performance including high compressive modulus and high ductility. The chitosan polymers not only endow the hydrogels with good biodegradability and biocompatibility, they also offer intrinsic antibacterial capability. The quinone groups formed by Fe3+ oxidation and protonated amino groups of chitosan polymer further enhance antibacterial property of the hydrogels. Serving as one of the two types of crosslinking mechanisms, the catechol‐Fe3+ chelation can covalently link with amino, thiol, and imidazole groups, which substantially enhance the hydrogel's adhesion to biological tissues. The hydrogel's adhesion to porcine skin shows a lap shear strength of 18.1 kPa, which is 6‐time that of the clinically established Fibrin Glue's adhesion. The hydrogel also has a good hemostatic performance due to the superior tissue adhesion as demonstrated with a hemorrhaging liver model. Furthermore, the hydrogel can remarkably promote healing of bacteria‐infected wound. 相似文献
19.
《Advanced functional materials》2018,28(18)
Polyampholyte hydrogels are synthesized by one‐step copolymerization of cationic monomer 3‐(methacryloylamino)propyltrimethylammonium chloride, anionic monomers sodium p‐styrenesulfonate (NaSS), and methacrylic acid (MAA) without chemical crosslinker and adding salts. The hydrogels exhibit pH responsive shape memory behavior; the temporary shape of the hydrogel is formed manually after immersing in NaOH solution and fixed in HCl solution, while the shape recovery occurs by immersing in NaOH again. Most interestingly, the hydrogel shows a spontaneous shape change after the first shape memory cycle. When the recovered hydrogel with a little residual deformation is immersed in HCl again, it twists spontaneously and rapidly to the previous temporary shape. The spontaneous twisting and recovering can be repeated for ten times. Furthermore, the hydrogel swells quickly and is strengthened in HCl, while shrinks and weakens in NaOH during the shape change procedure. This unique synergistic effect of fast swelling, residual helical deformation, and increased strength plays a significant role in the spontaneous shape alternation. This new finding will initiate a new prosperous design for new soft actuators requiring successive actions. 相似文献
20.
Direct 3D Printing of High Strength Biohybrid Gradient Hydrogel Scaffolds for Efficient Repair of Osteochondral Defect
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Fei Gao Ziyang Xu Qingfei Liang Bo Liu Haofei Li Yuanhao Wu Yinyu Zhang Zifeng Lin Mingming Wu Changshun Ruan Wenguang Liu 《Advanced functional materials》2018,28(13)
The emerging 3D printing technique allows for tailoring hydrogel‐based soft structure tissue scaffolds for individualized therapy of osteochondral defects. However, the weak mechanical strength and uncontrollable swelling intrinsic to conventional hydrogels restrain their use as bioinks. Here, a high‐strength thermoresponsive supramolecular copolymer hydrogel is synthesized by one‐step copolymerization of dual hydrogen bonding monomers, N‐acryloyl glycinamide, and N‐[tris(hydroxymethyl)methyl] acrylamide. The obtained copolymer hydrogels demonstrate excellent mechanical properties—robust tensile strength (up to 0.41 MPa), large stretchability (up to 860%), and high compressive strength (up to 8.4 MPa). The rapid thermoreversible gel ? sol transition behavior makes this copolymer hydrogel suitable for direct 3D printing. Successful preparation of 3D‐printed biohybrid gradient hydrogel scaffolds is demonstrated with controllable 3D architecture, owing to shear thinning property which allows continuous extrusion through a needle and also immediate gelation of fluid upon deposition on the cooled substrate. Furthermore, this biohybrid gradient hydrogel scaffold printed with transforming growth factor beta 1 and β‐tricalciumphosphate on distinct layers facilitates the attachment, spreading, and chondrogenic and osteogenic differentiation of human bone marrow stem cells (hBMSCs) in vitro. The in vivo experiments reveal that the 3D‐printed biohybrid gradient hydrogel scaffolds significantly accelerate simultaneous regeneration of cartilage and subchondral bone in a rat model. 相似文献