Cardiac tissue regeneration is an integrated process involving both cells and supporting matrix. Cardiomyocytes and stem cells are utilized to regenerate cardiac tissue. Hydrogels, because of their tissue-like properties, have been used as supporting matrices to deliver cells into infarcted cardiac muscle. Bioactive and biocompatible hydrogels mimicking biochemical and biomechanical microenvironments in native tissue are needed for successful cardiac tissue regeneration. These hydrogels not only retain cells in the infarcted area, but also provide support for restoring myocardial wall stress and cell survival and functioning. Many hydrogels, including natural polymer hydrogels, synthetic polymer hydrogels, and natural/synthetic hybrid hydrogels are employed for cardiac tissue engineering. In this review, types of hydrogels used for cardiac tissue engineering are briefly introduced. Their advantages and disadvantages are discussed. Furthermore, strategies for cardiac regeneration using hydrogels are
Gelatin hydrogels can mimic the microenvironments of natural tissues and encapsulate cells homogeneously, which makes them attractive for cartilage tissue engineering. Both the mechanical and biochemical properties of hydrogels can affect the phenotype of chondrocytes. However, the influence of each property on chondrocyte phenotype is unclear due to the difficulty in separating the roles of these properties. In this study, we aimed to study the influence of hydrogel stiffness on chondrocyte phenotype while excluding the role of biochemical factors, such as adhesion site density in the hydrogels. By altering the degree of methacryloyl functionalization, gelatin hydrogels with different stiffnesses of 3.8, 17.1, and 29.9 kPa Youngs modulus were prepared from the same concentration of gelatin methacryloyl (GelMA) macromers. Bovine articular chondrocytes were encapsulated in the hydrogels and cultured for 14 days. The influence of hydrogel stiffness on the cell behaviors including cell viability, cell
TY - JOUR. T1 - Polypyrrole/Alginate Hybrid Hydrogels. T2 - Electrically Conductive and Soft Biomaterials for Human Mesenchymal Stem Cell Culture and Potential Neural Tissue Engineering Applications. AU - Yang, Sumi. AU - Jang, Lindyk. AU - Kim, Semin. AU - Yang, Jongcheol. AU - Yang, Kisuk. AU - Cho, Seung Woo. AU - Lee, Jae Young. PY - 2016/11/1. Y1 - 2016/11/1. N2 - Electrically conductive biomaterials that can efficiently deliver electrical signals to cells or improve electrical communication among cells have received considerable attention for potential tissue engineering applications. Conductive hydrogels are desirable particularly for neural applications, as they can provide electrical signals and soft microenvironments that can mimic native nerve tissues. In this study, conductive and soft polypyrrole/alginate (PPy/Alg) hydrogels are developed by chemically polymerizing PPy within ionically cross-linked alginate hydrogel networks. The synthesized hydrogels exhibit a Youngs modulus of ...
Intrarenal drug delivery from a hydrogel carrier implanted under the kidney capsule is an innovative way to induce kidney tissue regeneration and/or prevent kidney inflammation or fibrosis. We report here on the development of supramolecular hydrogels for this application. We have synthesized two types of supramolecular hydrogelators by connecting the hydrogen bonding moieties to poly(ethylene glycols) in two different ways in order to obtain hydrogels with different physico-chemical properties. Chain-extended hydrogelators containing hydrogen bonding units in the main chain, and bifunctional hydrogelators end-functionalized with hydrogen bonding moieties, were made. The influence of these hydrogels on the renal cortex when implanted under the kidney capsule was studied. The overall tissue response to these hydrogels was found to be mild, and minimal damage to the cortex was observed, using the infiltration of macrophages, formation of myofibroblasts, and the deposition of collagen III as ...
Some cationic composite hydrogels based on chitosan (CS) and poly (N-2-aminoethyl acrylamide) (PAEA) covalently cross-linked with glutaraldehyde (GA) were tested as novel sorbents for two dis-azo dyes: Congo Red and Direct Blue 1. Three CS-based composite hydrogels having different molar ratios between the primary amine groups and the cross-linking agent (GA/NH2 = 5.3 and 12.5), the same total concentration of polycations (CPC = 2 wt%) and two molar ratios between polycations (PAEA:CS = 0.25 and 1.2) were used for this study. Pseudo-first order model, pseudo-second order model and the intraparticle diffusion model were used to analyze the experimental data in order to establish the mechanism of adsorption. The adsorption kinetics has been well described by the pseudo-second order model. The effect of temperature on the adsorption of both dyes has been also investigated.
Noncovalently cross-linked networks are attractive hydrogel platforms because of their facile fabrication, dynamic behavior, and biocompatibility. The majority of noncovalently cross-linked hydrogels, however, exhibits poor mechanical properties, which significantly limit their utility in load bearing applications. To address this limitation, hydrogels are presented composed of micelles created from genetically engineered, amphiphilic, elastin-like polypeptides that contain a relatively large hydrophobic block and a hydrophilic terminus that can be cross-linked through metal ion coordination. To create the hydrogels, heat is firstly used to trigger the self-assembly of the polypeptides into monodisperse micelles that display transition metal coordination motifs on their coronae, and subsequently cross-link the micelles by adding zinc ions. These hydrogels exhibit hierarchical structure, are stable over a large temperature range, and exhibit tunable stiffness, self-healing, and fatigue ...
TY - JOUR. T1 - Bioinspired glycosaminoglycan hydrogels via click chemistry for 3D dynamic cell encapsulation. AU - Kuang, Liangju. AU - Damayanti, Nur P.. AU - Jiang, Chunhui. AU - Fei, Xing. AU - Liu, Wenjie. AU - Narayanan, Naagarajan. AU - Irudayaraj, Joseph Maria Kumar. AU - Campanella, Osvaldo. AU - Deng, Meng. PY - 2019/2/5. Y1 - 2019/2/5. N2 - Cell encapsulation within 3D hydrogels is an attractive approach to develop effective cell-based therapies. However, little is known about how cells respond to the dynamic microenvironment resulting from hydrogel gelation-based cell encapsulation. Here, a tunable biomimetic hydrogel system that possesses alterable gelation kinetics and biologically relevant matrix stiffness is developed to study 3D dynamic cellular responses during encapsulation. Hydrogels are synthesized by crosslinking thiolated hyaluronic acid and thiolated chondroitin sulfate with poly(ethylene glycol) diacrylate under cell-compatible conditions. Hydrogel properties are ...
TY - JOUR. T1 - Preparation and properties of biodegradable hydrogels based on glutaraldehyde-crosslinked poly(2-hydroxyethyl aspartamide). AU - Kim, Jeong Hoon. AU - Sim, Sang Jun. AU - Lee, Dong Hyun. AU - Kim, Dukjoon. AU - Lee, Young Kwan. AU - Kim, Ji Heung. PY - 2004. Y1 - 2004. N2 - α, β-Poly(N-2-hydroxyethyl-DL-aspartamide), PHEA, one of the poly(amino acid)s having pendent hydroxyl groups, is biodegradable and biocompatible, and has been studied as a useful biomaterial, especially for drug delivery, by appropriate structural modification. In this work, PHEA, which we derived from polysuccinimide, was crosslinked by glutaraldehyde units in the presence of an acid catalyst to provide hydrogels with relatively good gel strength. The dry gels were formed into pressed discs, and their swelling behavior was investigated in different media under various conditions (pH, temperature, etc). In addition, we examined the hydrolytic degradation in aqueous solution. A porous scaffold was fabricated ...
Poly(vinyl alcohol) (PVA)/Ag-zeolite nanocomposite hydrogels were prepared by UV irradiation using PVA solution mixed with Ag-zeolite nanoparticles. Physical properties and changes in morphology of the PVA/Ag-zeolite hydrogels were investigated. The PVA/Ag-zeolite hydrogels were prepared at a PVA concentration of 9 wt% with a UV irradiation distance of 15 cm, where gel fraction and swelling ratio were optimized. Hardness of the PVA/Ag-zeolite hydrogels decreased with increasing amounts of Ag-zeolite, reaching that of soft elastomer when the amount of Ag-zeolite was 5 % by weight. The PVA/Ag-zeolite hydrogels showed strong antimicrobial activities against Staphylococcus aureus and Klebsiellapneumoniae, inducing a reduction of bacteria of over 99.9 % at a Ag-zeolite content of 3 wt ...
Supramolecular assemblies are promising building blocks for the fabrication of functional soft devices for high-tech applications. However, there is a lack of effective methods for large-scale manipulation and integration of nano-sized supramolecular structures on soft substrate. Now, functional soft devices composed of micellar filaments and hydrogels can be created through a versatile approach involving guided dewetting, transfer-printing, and laser-assisted patterning. Such an approach enables unprecedented control over the location and alignment of the micellar filaments on hydrogel substrates. As examples, freely suspended micellar fishnets immobilized on hydrogels are formed, showing the capability of trapping and releasing micro-objects and the piconewton force sensitivity. By incorporating responsive moieties into hydrogels, shape-morphing actuators with micelle-controlled rolling directionality are constructed. ...
In this study, the release of recombinant human interleukin-2 (rhlL-2) from methacrylated dextran (dex-MA) and (lactate-)hydroxyethyl methacrylated dextran (dex-(lactate-)HEMA) hydrogels with varying crosslink density was investigated. Hydrogels derived from dex-MA are stable under physiological conditions (pH 7 and 37degreesC), whereas dex-HEMA and dex-lactate-HEMA hydrogels degrade due to the presence of hydrolytically sensitive esters in the crosslinks of the gels. The protein release profiles both the non-degradable and degradable dextran-based hydrogels showed that with increasing crosslink density of the get, the release of rhIL-2 decreases. From dex-MA hydrogels with an initial water content above 70%, the rhIL-2 release followed Fickian diffusion, whereas from gels with an initial water content of 70% or lower the protein was fully entrapped in the hydrogel meshes. In contrast with non-degradable dex-MA hydrogels, degradable dex-lactate-HEMA gels with comparable network characteristics ...
TY - JOUR. T1 - Time controlled release of arabinofuranosylcytosine (Ara-C) from agarose hydrogels using layer-by-layer assembly. T2 - Journal of Biomaterials Science, Polymer Edition. AU - Mehrotra,Sumit. AU - Lynam,Daniel. AU - Liu,Chun. AU - Shahriari,Dena. AU - Lee,Ilsoon. AU - Tuszynski,Mark. AU - Sakamoto,Jeffrey. AU - Chan,Christina. PY - 2012. Y1 - 2012. N2 - Experimentally induced axonal regeneration is compromised by glial scar formation arising from leptomeningeal fibroblasts cells in and around the hydrogel scaffold implanted for nerve repair. Strategies are needed to prevent such fibroblastic reactive cell layer formation for enhanced axonal regeneration. Here, we implement the technique of layer-by-layer assembled degradable, hydrogen bonded multilayers on agarose hydrogels to incorporate an anti-mitotic drug (1-β-D-arabinofuranosylcytosine (Ara-C)) within the agarose hydrogels. We show controlled release of Ara-C under physiological conditions over a period of days. The ...
The similarity between the extracellular matrix of soft tissue and hydrogels, characterized by high-water-content viscoelastic polymeric networks, has been sustaining the advancement of hydrogels for tissue engineering and regenerative medicine (TERM) purposes. Current research on hydrogels has focused on introducing cell-adhesive peptides to promote cell adhesion and spreading, a critical applicability limitation. Here we report the development of gellan gum (GG) spongy-like hydrogels with ameliorated mechanical performance and flexibility in relation to hydrogels, using a simple and cost-effective method. Most importantly, these materials allow the entrapment of different cell types representing mesenchymal, epidermal and osteoblastic phenotypes that spread within the three-dimensional microstructure. This effect was associated with microstructural rearrangements characterized by pore wall thickening and pore size augmentation, and lower water content than precursor hydrogels. These properties ...
Hydrogels, formed through crosslinking of hydrophilic polymer chains, represent a class of materials that are capable of holding large volumes of water. Here we report a novel class of hydrophobic hydrogels that can free-float on the surface of different aqueous media by coating conventional hydrogels with a layer of hydrophobic microparticles. We further demonstrate that these floating hydrogel-based devices can be used for sensing applications on liquid surfaces such as the construction of floating pH meters. Moreover, we demonstrate that the floating hydrogels present high mobility with excellent self-assembling property on the surface of water. Importantly, the floating systems reserved the intrinsic biocompatibility of the core hydrogels, enabling microengineering of floating tissue constructs. It is expected that these floating hydrophobic hydrogel-based devices will likely find widespread applications including but not limited to sensing, tissue engineering, and biomedicine. ...
In this study, acrylamide-based hydrogels are synthesized by free radical solution polymerization in aqueous solution using ethylene glycol dimethacrylate (EGDMA) and its derivative polyethylene glycol dimethacrylate (PEGDMA) with different molecular weights as crosslinkers in the solution medium. The Fourier transform infrared spectroscopy technique is used for the structural characterization of the hydrogels. Dynamic swelling tests are conducted on acrylamide-based hydrogels for the determination of the swelling characteristics with respect to different crosslinking concentrations at room temperature. The parameters of swelling kinetics and diffusion mechanisms of the hydrogels are calculated with the aid of the data obtained. Accordingly, PEGDMA and EGDMA absorption capacity is found to increase with increasing concentrations. The lowest and highest water absorption capacities in PEGDMA(810) and EGDMA crosslinked hydrogels are 22.73-48.39 and 10.15-16.02 g/g, respectively. Water intake of ...
Injectable and biodegradable supramolecular hydrogels were prepared by nucleobase (adenine/thymine)-terminated poly(ethylene oxide)s (A-PEG-A/T-PEG-T) and α-cyclodextrin (α-CD). The supramolecular hydrogels were thoroughly characterized by WXRD, rheometer, and SEM. The gelation time depended on the molecular
Large-scaled composite hydrogels (several. centimeters) have been prepared for use in biomedical applications such as cartilage and bone. However, few preparation methods of nanocomposites of PVA and Hap have been reported. In this study, the nano-, microparticles of PVA, HAp and DNA were obtained by using high hydrostatic pressure technology. It is thought that this is achieved by the pressure-induced Inhibitors,research,lifescience,medical quick formation of PVA particles that could incorporate secondary and third substrates, such as DNA and HAp, without phase separation [15, 31]. 3.2. Cytotoxicity Test Figure 4 shows the result of the cytotoxicity test of PVA/DNA and PVA/HAp/DNA complexes. Inhibitors,research,lifescience,medical The high viability of COS-7 cells incubated with them is shown, irrespective of the concentration of PVA and HAp. PVA and HAp are biocompatible materials [32, 33]. The PVA/DNA complex is nontoxic. because of the composite formation of PVA and DNA via hydrogen bonding ...
We report here on new composite polymer hydrogel particles with light-absorbing carbon particles incorporated within them that can be used as draw agents in the forward osmosis process of desalination. These hydrogels are synthesized by free-radical polymerization of different monomers (e.g. sodium acrylate, N-isopropylacrylamide or their mixtures) and the crosslinker N,N′-methylenebisacrylamide with light-absorbing carbon particles. We have previously shown that hydrogel particles are able to draw pure water through forward osmosis membranes, and then the water can be removed by pressure or heating, or a mixture of both. The incorporation of light-absorbing particles leads to natural, enhanced heating and dewatering of the composites compared to neat hydrogels during such irradiation with light. However, it is also advantageously found that these composite polymer hydrogels exhibit higher swelling ratios, and thus produce higher water fluxes in the FO process. Furthermore, with the increasing ...
Hydrogels releasing or producing NO, most preferably photopolymerizable biodegradable hydrogels capable of releasing physiological amounts of NO for prolonged periods of time, are applied to sites on or in a patient in need of treatment thereof for disorders such as restenosis, thrombosis, asthma, wound healing, arthritis, penile erectile dysfunction or other conditions where NO plays a significant role. The hydrogels are typically formed of macromers, which preferably include biodegradable regions, and have bound thereto groups that are released in situ to elevate or otherwise modulate NO levels at the site where treatment is needed. The macromers can form a homo or hetero-dispersion or solution, which is polymerized to form a hydrogel material, that in the latter case can be a semi-interpenetrating network or interpenetrating network. Compounds to be released can be physically entrapped, covalently or ionically bound to macromer, or actually form a part of the polymeric material. The hydrogel ...
Injectable hydrogels with biodegradability have in situ formability which in vitro/in vivo allows an effective and homogeneous encapsulation of drugs/cells, and convenient in vivo surgical operation in a minimally invasive way, causing smaller scar size and less pain for patients. Therefore, they have found
TY - JOUR. T1 - Enhanced tissue production through redox control in stem cell-laden hydrogels. AU - Reid, Branden. AU - Afzal, Junaid M.. AU - Mccartney, Annemarie M.. AU - Abraham, M. Roselle. AU - ORourke, Brian. AU - Elisseeff, Jennifer Hartt. PY - 2013/9/1. Y1 - 2013/9/1. N2 - Cellular bioenergetics and redox (reduction-oxidation) play an important role in cell proliferation and differentiation, key aspects of building new tissues. In the present study, we examined the metabolic characteristics of human adipose-derived stem cells (hASCs) during proliferation and differentiation in both monolayer and three-dimensional biomaterial scaffolds. In monolayer, hASCs exhibited higher glycolysis and lower ox-phos as compared to both adipogenic and osteogenic differentiated cells, and hASCs demonstrated the Warburg effect (aerobic glycolysis). However, reactive oxygen species (ROS) levels increased during adipogenic differentiation, but decreased during osteogenic differentiation. Similarly, a ...
The main focus of this thesis centers on the development of stimuli-responsive hydrogels that have utility for pH-responsive valves, biomacromolecule sensing, irreversible biomacromolecule immobilization, and reversible biomacromolecule immobilization. Each system discussed has its function derived from a novel fabrication protocol or through the development of new hybrid polymer biomaterials. Molecular sensing was accomplished by preparing crosslink-cleavable hydrogels with progressively more complex recognition elements. Initial work investigated the swelling kinetics of disulfide crosslinked hydrogels as a model system for protease responsive hydrogels. More complex peptide-containing hydrogels that have utility for biomacromolecule detection, were then prepared using a novel disulfide-exchange protocol for the preparation of methacrylamide containing peptides. Utilizing this protocol, methacrylamide containing peptides that were responsive to alpha-chymotrypsin (CKYC) and botulism neurotoxin ...
Bioactive hydrogels formed by Michael-type addition reactions of end-functionalized poly(ethylene glycol) macromers with cysteine-containing peptides have been described as extracellular matrix mimetics and tissue engineering scaffolds. Although these materials have shown favorable behavior in vivo in tissue repair, we sought to develop materials formulations that would be more rapidly responsive to cell-induced enzymatic remodeling. In this study, protease-sensitive peptides that have increased k(cat) values were characterized and evaluated for their effects on gel degradability. Biochemical properties for soluble peptides and hydrogels were examined for matrix metalloproteinase (MMP)-1 and MMP-2. The most efficient peptide substrates in some cases overlap and in other cases differ between the two enzymes tested, and a range of k(cat) values was obtained. For each enzyme, hydrogels formed using the peptides with higher k(cat) values degraded faster than a reference with lower k(cat). ...
Self-healing hydrogels are a specialized type of polymer hydrogel. A hydrogel is a macromolecular polymer gel constructed of a network of crosslinked polymer chains. Hydrogels are synthesized from hydrophilic monomers by either chain or step growth, along with a functional crosslinker to promote network formation. A net-like structure along with void imperfections enhance the hydrogels ability to absorb large amounts of water via hydrogen bonding. As a result, hydrogels, self-healing alike, develop characteristic firm yet elastic mechanical properties. Self-healing refers to the spontaneous formation of new bonds when old bonds are broken within a material. The structure of the hydrogel along with electrostatic attraction forces drive new bond formation through reconstructive covalent dangling side chain or non-covalent hydrogen bonding. These flesh-like properties have motivated the research and development of self-healing hydrogels in fields such as reconstructive tissue engineering as ...
In order for transplanted cells to survive in the body, they need to be gently implanted, as well as provide a suitable environment allowing them to attach, survive, grow and function. Because different cell types prefer different types of environments, the delivery matrix can be modified. The HyStem® hydrogels permit gentle implantation by supporting cells when they are injected through a needle. HyStem® hydrogels are highly customizable, allowing for a variation of gel stiffness, viscosity and gelation time. They are also biocompatible. BioTime has designed these hydrogels to dissolve when needed to gently release cells from the matrix.. In addition to cells, proteins and/or other biological factors it can also be used as a time-release depot for drugs or biological molecules.. The technology underlying BioTimes HyStem® hydrogels was developed at the University of Utah and is based on a unique chemical cross-linking strategy. Building upon this platform, BioTime has developed the HyStem ...
File:Physical link.jpg Physical hydrogels are not homogeneous, since the molecular entanglements or hydrophobic or ionic domains can form clusters, creating inhomogeneities. One example of the hydrogels in this class is calcium alginate hydrogel. When a polyelectrolyte is exposed to multivalent ions of the opposite charge, this so-called "ionotropic" hydrogel is formed. The gelation or precipitation depends on the concentration of the ions, the ionic strength, and pH of the solution. The interactions in these hydrogels are reversible, which means they can be disrupted by changes in the physical conditions, including stress, temperature, and pH.[1] Chemical Hydrogels The hydrogels are called "permanent" or "chemical" gels if they form covalently-crosslinked networks. The crosslinkers are small molecules with functional groups, which could be polymerized with the macromers, forming bridges that connect these lengthy polymer chains and eventually result in a hydrogel network. This class of ...
Before we start this issue of J-club, I would like to recommend Prof. Langers lecture for his MRS Von Hippel Award in the 2005 MRS Fall Meeting (Langer, 2006). His lecture not only delineated the history of the new exciting field of drug delivery and controlled release, but also told us many interesting stories happened in his career development. With Prof. Langers pioneer work, many new materials are developed for designing new drug delivery and controlled drug release systems. Environmentally responsive (ER) hydrogels are one of such materials. ER hydrogels can experience an abrupt volume change and hence hold or release a large amount of solvent under the change of environmental conditions, such as temperatures, pH values, and electric signals. Two recent review papers (Qiu and Park, 2001; and Bromberg and Ron, 1998) provide excellent overviews of the state-of-the-art and challenges of ER hydrogels for drug delivery and controlled release applications. The mechanism of large volume change ...
The present work investigates Ca2+-crosslinked nanofibrillated cellulose hydrogels as potential hemostatic wound dressings by studying core interactions between the materials and a central component of wounds and wound healing-the blood. Hydrogels of wood-derived anionic nanofibrillated cellulose (NFC) and NFC hydrogels that incorporate kaolin or collagen are studied in an in vitro whole blood model and with platelet-free plasma assays. The evaluation of thrombin and factor XIIa formation, platelet reduction, and the release of activated complement system proteins, shows that the NFC hydrogel efficiently triggered blood coagulation, with a rapid onset of clot formation, while displaying basal complement system activation. By using the NFC hydrogel as a carrier of kaolin, the onset of hemostasis is further boosted, while the NFC hydrogel containing collagen exhibits blood activating properties comparable to the anionic NFC hydrogel. The herein studied NFC hydrogels demonstrate great potential for ...
Bacterial cellulose (BC) based hydrogels (BC-PVP and BC-CMC) are modified with β-tri-calcium phosphate (β-TCP) and hydroxyapatite (HA) to improve the structural and functional properties of the existing hydrogel scaffolds. The modified hydrogels are then biomineralized with CaCO3 following liquid diffusion technique, where salt solutions of Na2CO3 (5.25 g/100 mL) and CaCl2 (7.35 g/100 mL) were involved. The BC-PVP and BC-CMC are being compared with the non-mineralized (BC-PVP-β-TCP/HA and BC-CMC-β-TCP/HA) and biomineralized (BC-PVP-β-TCP/HA-CaCO3 and BC-CMC-β-TCP/HA-CaCO3) hydrogels on the basis of their structural and rheological properties. The Fourier Transform Infrared (FTIR) spectral analysis demonstrated the presence of BC, CMC, PVP, β-TCP, HA in the non-mineralized and BC, CMC, PVP, β-TCP, HA and CaCO3 in the biomineralized samples. Interestingly, the morphological property of non-mineralized and biomineralized, hydrogels are different than that of BC-PVP and BC-CMC based novel ...
In situ forming hydrogels were developed from 4-arm poly(ethylene glycol)?methacrylate (PEG-4-MA) and ?tetrazole (PEG-4-Tet) derivatives through catalyst-free and bioorthogonal "tetrazole?alkene" photo-click chemistry. PEG-4-MA and PEG-4-Tet (Mn = 10 kg/mol) were soluble at 37 °C in phosphate buffer (PB, pH 7.4, 10 mM) at total polymer concentrations ranging from 20 to 60 wt % but formed fluorescent hydrogels upon 365 nm UV irradiation at an intensity of 20.6, 30.7, or 60 mW/cm2. The gelation times ranged from ca. 50 s to 5 min, and storage moduli varied from 0.65 to 25.2 kPa depending on polymer concentrations and degrees of Tet substitution in PEG-4-Tet conjugates. The cell experiments via an indirect contact assay demonstrated that these "tetrazole?alkene" photo-click PEG hydrogels were noncytotoxic. The high specificity of photo-click reaction renders ...
Tissue engineering typically requires a use of scaffolds when delivering tissue-specific cells to be engineered. Hydrogels are frequently used as scaffolds, because their composition, structure, and function resemble the natural tissue extracellular matrix. In this study, hyaluronate-alginate hybrid (HAH) was synthesized by conjugating alginate (ALG) with the hyaluronate (HA) backbone using various types of linkers. HAH hydrogel was prepared by physically cross-linking the HAH polymer in the presence of calcium ions without chemical cross-linkers. The mechanical stiffness of HAH hydrogel was significantly affected by changing the type of a linker between HA and ALG. The mechanical stiffness increased with increasing linker length, likely due to enhanced intermolecular reactions between HA and ALG. This enables controlling the mechanical properties of HAH hydrogels. The types of linkers used to synthesize HAHs also influenced the chondrogenic differentiation of ATDC5 cells cultured in HAH ...
University of Debrecen, HU. Keywords: chlorohexidine, dental, hydrogel, nanocopmosite. Hydrogels are three dimensional hydrophilic crosslinked polymer networks, which capable of swelling in water. They have soft and elastic nature, which suggests similarities to natural tissues. Hydrogels are important in dentistry. For example, PerioChip is a hydrogel, used in periodontology as a drug delivery device for the release of chlorhexidine digluconate (CHX). The Atrisorb a bioabsorbable hydrogel that can release antibiotic-doxycycline, or the Aristine what can delivery minocyclin hydrochloride to treat of acne. In this work nanocomposite biocompatible hydrogels (NCHG) were synthesised as model systems for in situ cured potentially local drug delivery devices for curing periodontal infections. The composite consists of the following components: nanoparticles (NPs), matrix gel, and CHX as antibacterial drug. The NPs were obtained by free radical initiated copolymerization of the monomers, 2-hydroxyethyl ...
Hybrid hydrogels containing vertically aligned carbon nanotubes with anisotropic electrical conductivity for muscle myofiber fabrication. on Wyss Institute
Fingerprint Dive into the research topics of Chromophore amphiphile-polyelectrolyte hybrid hydrogels for photocatalytic hydrogen production. Together they form a unique fingerprint. ...
The present invention relates to crosslinked polymers, synthesized through ring-opening polymerization of ethylenically unsaturated epoxides, in combination with α-hydroxy acids using a hydrophilic macroinitiator, such as poly(ethylene glycol), to form substituted copolymers having ethylenically unsaturated functionality randomly distributed along the polyester polymer backbone. That copolymer is subsequently crosslinked to form a hydrogel network. More particularly, the present invention relates to the synthesis of biodegradable poly(α-hydroxy acid-co-glycidyl methacrylate)-block-poly(ethylene glycol)-block-poly(α-hydroxy acid-co-glycidyl methacrylate) copolymers, which are subsequently crosslinked to form hydrogel networks. The invention also relates to the use of these hydrogel networks in various applications, in particular, for the controlled release of drugs and proteins.
Associate Professor Jin Kim Montclare of the Department of Chemical and Biomolecular Engineering received $368,000 over three years to fabricate patterned protein hydrogels for applications in sensing, drug delivery, and wound healing. As an example, these biomimetic materials could mimic the adhesion properties of the human body well enough to heal wounds. Montclare also envisions biomimetic materials that will be able to sense and control the flow of fluids, or even control the delivery of drugs within the bloodstream.. After testing the protein hydrogels, which are made from the Escherichia coli bacterium, they will be patterned onto various solid substrates to mimic biological functions. An example of this would be the patterning on a geckos finger that allows it to adhere to surfaces. A similarly designed protein hydrogel could yield a similar stickiness. Using different patterning, protein hydrogels can adopt various other capabilities seen in nature.. Montclares research differs from ...
Hydrogels are three-dimensional water-insoluble hydrophilic natural or synthetic polymer networks made up of crosslinked water-soluble polymers. The purpose of this study was to develop and directly compare photo crosslinked hydrogels on the basis of pure gelatin, alginate and hyaluronic acid as well as their blends. The functionalization of starting materials with methacrylate moieties was evaluated by 1H-NMR spectroscopy. Hydrogels were prepared from methacrylates by photo cross-linking using UV light. The effect of changing the hydrogel composition was quantified through examination of hydrogel swelling behavior and rheological properties. In addition, the viability and adhesion of neonatal rat cardiomyocytes (NRCM) seeded onto the hydrogels was examined by in vivo imaging of NRCM-mediated scaffold contraction as well as by histological evaluation after immunostaining. Biological testing showed good biocompatibility and cell survival in the presence of all materials discussed. Adhesion of ...
article{835383, author = {Censi, R and Vermonden, T and van Steenbergen, MJ and Deschout, Hendrik and Braeckmans, Kevin and De Smedt, Stefaan and van Nostrum, CF and di Martino, P and Hennink, WE}, issn = {0168-3659}, journal = {JOURNAL OF CONTROLLED RELEASE}, keyword = {GLYCOL) HYDROGELS,POLYMERIC MICELLES,DRUG-DELIVERY,MODEL PROTEINS,Fickian diffusion,Degradation,Swelling,Photopolymerization,Injectable thermosensitive hydrogels,DEGRADABLE NETWORKS,FLUORESCENCE RECOVERY,CONTROLLED-RELEASE,BIOMEDICAL APPLICATIONS,IN-VITRO,DEXTRAN}, language = {eng}, location = {Salt Lake City, UT, USA}, number = {3}, pages = {230--236}, title = {Photopolymerized thermosensitive hydrogels for tailorable diffusion-controlled protein delivery}, url = {http://dx.doi.org/10.1016/j.jconrel.2009.06.003}, volume = {140}, year = {2009 ...
Page contains details about Nile Red-loaded hyaluronic acid hydrogel . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Chemical engineers at MIT developed a way to add structure to hydrogels injected in the body as treatments, to prevent them from liquifying.
Novel supramolecular hydrogels were formed between pyrene-terminated poly(ethylene glycol) star polymers and γ-cyclodextrin (γ-CD), through the inclusion complexation of dimers of the pyrene terminals with γ-CD, where γ-CD was directly used as a supramolecular cross-linking reagent without any modification. © 2012 The Royal Society of Chemistry ...
Enzymatically degradable poly(ethylene glycol) hydrogels for the 3D culture and release of human embryonic stem cell derived pancreatic precursor cell aggregates Journal Article ...
HyStem® hydrogels key feature is the ability to control matrix characteristics by changing hydrogel stiffness or adding extracellular matrix (ECM) proteins and growth factors. HyStem hydrogels can be used to coat plates or encapsulate cells.
HyStem® hydrogels key feature is the ability to control matrix characteristics by changing hydrogel stiffness or adding extracellular matrix (ECM) proteins and growth factors. HyStem hydrogels can be used to coat plates or encapsulate cells.
Hydrogels that mimic the natural extracellular matrix (ECM) are used in three-dimensional cell culture, cell therapy, and tissue engineering. A semi-synthetic ECM based on cross-linked hyaluronana offers experimental control of both composition and gel stiffness. The mechanical properties of the ECM in part determine the ultimate cell phenotype. We now describe a rheological study of synthetic ECM hydrogels with storage shear moduli that span three orders of magnitude, from 11 to 3 500 Pa, a range important for engineering of soft tissues. The concentration of the chemically modified HA and the cross-linking density were the main determinants of gel stiffness. Increase in the ratio of thiol-modified gelatin reduced gel stiffness by diluting the effective concentration of the HA component. ...
Novel anionic hydrogels, containing acidic groups, and their preparation are described. These novel hydrogels are stable, three-dimensional polymer networks, having good water permeability and mechanical properties. They are obtained by simultaneous polymerization and cross-linking, in the presence of a polymerization catalyst, such as an organic peroxide, azobisisobutyronitrile or other free radical polymerization catalyst, of a mixture of (a) a heterocyclic monomer preferably an N-vinyl lactam, (b) a polymerizable acidic monomer, such as acrylic or methacrylic acid, sulfo-ethyl methacrylate or a sulfated or phosphated derivative of a hydroxyalkyl- acrylate or methacrylate and (c) a cross-linking agent, such as a glycol or polyglycol diacrylate or dimethacrylate and also, preferably, (d) at least one acrylic monomer capable of polymerizing to a very molecular weight, such as hydroxyethyl- or hydroxypropyl-acrylate or methacrylate, acrylamide or methacrylamide, or a lower alkyl acrylate or
The change in rheological and mechanical properties for some ionotropic cross-linked metal-alginate hydrogel complexes in particularly copper-alginate membranes in the presence of some organic solvents (benzene, toluene, xylene, carbon tetrachloride, ace-tone, chloroform, dichloroethane, isobutyl alcohol and ethyl alcohol) or buffer solutions (acetates, borates and universal buffers) have been investigated. The experimental results showed a remarkable tendency of the studied hydrogels for shrinking in polar solvents, whereas no influence was observed for the hydrogels in non-polar solvents. On the other hand, the gels were found to swell or shrink in the buffer solutions depending on the pH of the buffer used. The swelling extent for hydrogel spheres was found to decrease in the order Cu > Ba ≈ Ca > Zn > Pb-alginates in universal buffers of pH = 5.33. The factors affected this behavior have been examined and discussed.
The present work aims at computational analysis of environmentally responsive hydrogels with enormous prospective in the formulation aspect of drug delivery systems. The drug delivery potential of hydrogels to the targets is owing to the specific stimuli responsive nature of the hydrogels. The environmental factors looked upon in the study are changes in pH, alteration of temperature and glucose concentration rise originated in the body as a result of various disease conditions. Polymers, synthetic polypeptides and dendrimers have been used in the present work to study the feasibility of drug delivery. The computational methods have been used to formulate polymer properties, pharmacokinetics and toxicity studies. Diverse interactions approximating electrostatic, hydrophobic and hydrogen bond interactions acquire place during incorporation of drugs within the polymer and dendrimers. The covalent and electrostatic interactions between a drug and the surface of polymer and dendrimer have been ...
According to a multiphase mixture theory, we have mathematically developed a multiphysical model with chemoelectromechanical coupling considerations, termed the multieffect-coupling electric-stimulus (MECe) model, to simulate the responsive behavior of electric-sensitive hydrogels immersed in a bath solution under an externally applied electric field. For solutions of the MECe model consisting of coupled nonlinear partial differential governing equations, a meshless Hermite-Cloud method with a hierarchical iteration technique has been used for a one-dimensional steady-state analysis of a hydrogel strip. The computed results are compared with the experimental data, and there is very good agreement. Simulations within the domains of both hydrogels and surrounding solutions also present distributions of the ionic concentrations and electric potential as well as the hydrogel displacement. The effects of various physical parameters on the response behavior of electric-stimulus responsive hydrogels ...
Les hydrogels sont des structures en réseau 3D, obtenues à partir de polymères naturels ou synthétiques. Ces biomatériaux sont largement conçus et utilisés pour répondre aux besoins de diverses applications. Leur teneur en eau élevée, leur porosité, leur consistance molle et leur biocompatibilité sont des propriétés uniques qui les ont amenés à devenir très populaires. Basée à la Haute Ecole dingénierie et darchitecture de Fribourg - HEIA-FR, léquipe du professeur Roger Marti a développé une expertise autour des smart hydrogels et des stimuli responsive hydrogels.. Découvrez cette innovation et son potentiel dans cette nouvelle vidéo de la série Innosquare HES-SO, portée par la Fondation Inartis, qui nous amènera à la grande journée événement du 18 mai 2018 (inscriptions ci-dessous). Video. Inscriptions à la journée du 18 mai. ...