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Sample records for degradable peg-based hydrogel

  1. PEG-based degradable networks for drug delivery applications

    Science.gov (United States)

    Ostroha, Jamie L.

    The controlled delivery of therapeutic agents by biodegradable hydrogels has become a popular mechanism for drug administration in recent years. Hydrogels are three-dimensional networks of polymer chains held together by crosslinks. Although the changes which the hydrogel undergoes in solution are important to a wide range of experimental studies, they have not been investigated systematically and the factors which influence the degree of swelling have not been adequately described. Hydrogels made of poly(ethylene glycol) (PEG) will generally resist degradation in aqueous conditions, while a hydrogel made from a copolymer of poly(lactic acid) (PLA) and PEG will degrade via hydrolysis of the lactic acid group. This ability to degrade makes these hydrogels promising candidates for controlled release drug delivery systems. The goal of this research was to characterize the swelling and degradation of both degradable and non-degradable gels and to evaluate the release of different drugs from these hydrogels, where the key variable is the molecular weight of the PEG segment. These hydrogels were formed by the addition and subsequent chemically crosslinking of methacrylate end groups. During crosslinking, both PEG and LA-PEG-LA hydrogels of varied PEG molecular weight were loaded with Vitamin B12, Insulin, Haloperidol, and Dextran. It was shown that increasing PEG molecular weight produces a hydrogel with larger pores, thus increasing water uptake and degradation rate. While many environmental factors do not affect the swelling behavior, they do significantly impact the degradation of the hydrogel, and thus the release of incorporated therapeutic agents.

  2. Integration of Self-Assembled Microvascular Networks with Microfabricated PEG-Based Hydrogels.

    Science.gov (United States)

    Cuchiara, Michael P; Gould, Daniel J; McHale, Melissa K; Dickinson, Mary E; West, Jennifer L

    2012-11-07

    Despite tremendous efforts, tissue engineered constructs are restricted to thin, simple tissues sustained only by diffusion. The most significant barrier in tissue engineering is insufficient vascularization to deliver nutrients and metabolites during development in vitro and to facilitate rapid vascular integration in vivo. Tissue engineered constructs can be greatly improved by developing perfusable microvascular networks in vitro in order to provide transport that mimics native vascular organization and function. Here a microfluidic hydrogel is integrated with a self-assembling pro-vasculogenic co-culture in a strategy to perfuse microvascular networks in vitro. This approach allows for control over microvascular network self-assembly and employs an anastomotic interface for integration of self-assembled micro-vascular networks with fabricated microchannels. As a result, transport within the system shifts from simple diffusion to vessel supported convective transport and extra-vessel diffusion, thus improving overall mass transport properties. This work impacts the development of perfusable prevascularized tissues in vitro and ultimately tissue engineering applications in vivo.

  3. Viral infection of human progenitor and liver-derived cells encapsulated in three-dimensional PEG-based hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Nam-Joon; Elazar, Menashe; Xiong, Anming; Glenn, Jeffrey S [Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, CCSR Building Room 3115A, 269 Campus Drive, Stanford, CA 94305 (United States); Lee, Wonjae [Mechanical Engineering, Stanford University, Stanford, CA 94305 (United States); Chiao, Eric; Baker, Julie [Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 (United States); Frank, Curtis W, E-mail: jeffrey.glenn@stanford.ed, E-mail: curt.frank@stanford.ed [Department of Chemical Engineering, Stanford University, Stanford, CA 94305 (United States)

    2009-02-15

    We have studied the encapsulation of human progenitor cells into 3D PEG hydrogels. Replication-incompetent lentivirus promoter reporter vectors were found to efficiently detect the in vivo expression of human hepatic genes in hydrogel-encapsulated liver progenitor cells. Similarly, hydrogel-encapsulated cells could be efficiently infected with hepatitis C virus, and progeny infectious virus could be recovered from the media supernatants of the hydrogels. Provocatively, the diameters of these virus particles range from {approx}50 to 100 nm, while the calculated mesh size of the 8 k hydrogel is 44.6 +- 1.7 A. To reconcile how viral particles can penetrate the hydrogels to infect the encapsulated cells, we propose that microfractures/defects of the hydrogel result in a functional pore size of up to 20 fold greater than predicted by theoretical mesh calculations. These results suggest a new model of hydrogel structure, and have exciting implications for tissue engineering and hepatitis virus studies. (communication)

  4. Viral infection of human progenitor and liver-derived cells encapsulated in three-dimensional PEG-based hydrogel

    International Nuclear Information System (INIS)

    Cho, Nam-Joon; Elazar, Menashe; Xiong, Anming; Glenn, Jeffrey S; Lee, Wonjae; Chiao, Eric; Baker, Julie; Frank, Curtis W

    2009-01-01

    We have studied the encapsulation of human progenitor cells into 3D PEG hydrogels. Replication-incompetent lentivirus promoter reporter vectors were found to efficiently detect the in vivo expression of human hepatic genes in hydrogel-encapsulated liver progenitor cells. Similarly, hydrogel-encapsulated cells could be efficiently infected with hepatitis C virus, and progeny infectious virus could be recovered from the media supernatants of the hydrogels. Provocatively, the diameters of these virus particles range from ∼50 to 100 nm, while the calculated mesh size of the 8 k hydrogel is 44.6 ± 1.7 A. To reconcile how viral particles can penetrate the hydrogels to infect the encapsulated cells, we propose that microfractures/defects of the hydrogel result in a functional pore size of up to 20 fold greater than predicted by theoretical mesh calculations. These results suggest a new model of hydrogel structure, and have exciting implications for tissue engineering and hepatitis virus studies. (communication)

  5. Design of multimodal degradable hydrogels for controlled therapeutic delivery

    Science.gov (United States)

    Kharkar, Prathamesh Madhav

    thiol exchange reaction facilitated rapid and responsive protein release in the presence of GSH. A photolabile o-nitrobenzyl ether group (o-NB) was subsequently incorporated within the PEG-based, gel-forming monomers to demonstrate cargo release triggered by exogenous stimuli for patient-specific therapies. Upon the application of cytocompatible doses of light, the photolabile o-NB linkage underwent irreversible cleavage yielding ketone and carboxylic acid-based cleavage products. Hydrogel degradation kinetics was characterized in response to externally applied cytocompatible light or GSH in aqueous microenvironments. By incorporating a photodegradable o-nitrobenzyl ether group, a thiol-sensitive succinimide thioether linkage, and ester linkages within the hydrogels, we demonstrated unique control over degradation via surface erosion or bulk degradation mechanisms, respectively, with degradation rate constants ranging from 10-1 min-1 to 10-4 min-1. As a proof of concept, the controlled release of nanobeads from the hydrogel was demonstrated in a preprogrammed and stimuli-responsive fashion. The multimodal degradable hydrogels were then investigated for the local controlled release of small molecular weight proteins, which are of interest for regulating various cellular functions and fates in vivo. Low molecular weight heparin, a highly sulfated polysaccharide was incorporated within the hydrogel network by Michael-type reaction due to its affinity with biologics such as growth factors and immunomodulatory proteins. Incorporation of reduction-sensitive linkages resulted in 2.3 fold differences in the release profile of fibroblast growth factor-2 (FGF-2) in the presence of GSH compared to non-reducing microenvironment. Bioactivity of released FGF-2 was comparable to pristine FGF-2, indicating the ability of the hydrogel to retain bioactivity of cargo molecules during encapsulation and release. Further, preliminary in vivo studies demonstrated control over hydrogel

  6. Modulation of Huh7.5 spheroid formation and functionality using modified PEG-based hydrogels of different stiffness.

    Directory of Open Access Journals (Sweden)

    Bae Hoon Lee

    Full Text Available Physical cues, such as cell microenvironment stiffness, are known to be important factors in modulating cellular behaviors such as differentiation, viability, and proliferation. Apart from being able to trigger these effects, mechanical stiffness tuning is a very convenient approach that could be implemented readily into smart scaffold designs. In this study, fibrinogen-modified poly(ethylene glycol-diacrylate (PEG-DA based hydrogels with tunable mechanical properties were synthesized and applied to control the spheroid formation and liver-like function of encapsulated Huh7.5 cells in an engineered, three-dimensional liver tissue model. By controlling hydrogel stiffness (0.1-6 kPa as a cue for mechanotransduction representing different stiffness of a normal liver and a diseased cirrhotic liver, spheroids ranging from 50 to 200 μm were formed over a three week time-span. Hydrogels with better compliance (i.e. lower stiffness promoted formation of larger spheroids. The highest rates of cell proliferation, albumin secretion, and CYP450 expression were all observed for spheroids in less stiff hydrogels like a normal liver in a healthy state. We also identified that the hydrogel modification by incorporation of PEGylated-fibrinogen within the hydrogel matrix enhanced cell survival and functionality possibly owing to more binding of autocrine fibronectin. Taken together, our findings establish guidelines to control the formation of Huh7.5 cell spheroids in modified PEGDA based hydrogels. These spheroids may serve as models for applications such as screening of pharmacological drug candidates.

  7. Facile synthesis of degradable and electrically conductive polysaccharide hydrogels.

    Science.gov (United States)

    Guo, Baolin; Finne-Wistrand, Anna; Albertsson, Ann-Christine

    2011-07-11

    Degradable and electrically conductive polysaccharide hydrogels (DECPHs) have been synthesized by functionalizing polysaccharide with conductive aniline oligomers. DECPHs based on chitosan (CS), aniline tetramer (AT), and glutaraldehyde were obtained by a facile one-pot reaction by using the amine group of CS and AT under mild conditions, which avoids the multistep reactions and tedious purification involved in the synthesis of degradable conductive hydrogels in our previous work. Interestingly, these one-pot hydrogels possess good film-forming properties, electrical conductivity, and a pH-sensitive swelling behavior. The chemical structure and morphology before and after swelling of the hydrogels were verified by FT-IR, NMR, and SEM. The conductivity of the hydrogels was tuned by adjusting the content of AT. The swelling ratio of the hydrogels was altered by the content of tetraaniline and cross-linker. The hydrogels underwent slow degradation in a buffer solution. The hydrogels obtained by this facile approach provide new possibilities in biomedical applications, for example, biodegradable conductive hydrogels, films, and scaffolds for cardiovascular tissue engineering and controlled drug delivery.

  8. A thermo-degradable hydrogel with light-tunable degradation and drug release.

    Science.gov (United States)

    Hu, Jingjing; Chen, Yihua; Li, Yunqi; Zhou, Zhengjie; Cheng, Yiyun

    2017-01-01

    The development of thermo-degradable hydrogels is of great importance in drug delivery. However, it still remains a huge challenge to prepare thermo-degradable hydrogels with inherent degradation, reproducible, repeated and tunable dosing. Here, we reported a thermo-degradable hydrogel that is rapidly degraded above 44 °C by a facile chemistry. Besides thermo-degradability, the hydrogel also undergoes rapid photolysis with ultraviolet light. By embedding photothermal nanoparticles or upconversion nanoparticles into the gel, it can release the entrapped cargoes such as dyes, enzymes and anticancer drugs in an on-demand and dose-tunable fashion upon near-infrared light exposure. The smart hydrogel works well both in vitro and in vivo without involving sophisticated syntheses, and is well suited for clinical cancer therapy due to the high transparency and non-invasiveness features of near-infrared light. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Non-invasive monitoring of in vivo hydrogel degradation and cartilage regeneration by multiparametric MR imaging

    Science.gov (United States)

    Chen, Zelong; Yan, Chenggong; Yan, Shina; Liu, Qin; Hou, Meirong; Xu, Yikai; Guo, Rui

    2018-01-01

    Numerous biodegradable hydrogels for cartilage regeneration have been widely used in the field of tissue engineering. However, to non-invasively monitor hydrogel degradation and efficiently evaluate cartilage restoration in situ is still challenging. Methods: A ultrasmall superparamagnetic iron oxide (USPIO)-labeled cellulose nanocrystal (CNC)/silk fibroin (SF)-blended hydrogel system was developed to monitor hydrogel degradation during cartilage regeneration. The physicochemical characterization and biocompatibility of the hydrogel were evaluated in vitro. The in vivo hydrogel degradation and cartilage regeneration of different implants were assessed using multiparametric magnetic resonance imaging (MRI) and further confirmed by histological analysis in a rabbit cartilage defect model for 3 months. Results: USPIO-labeled hydrogels showed sufficient MR contrast enhancement and retained stability without loss of the relaxation rate. Neither the mechanical properties of the hydrogels nor the proliferation of bone-marrow mesenchymal stem cells (BMSCs) were affected by USPIO labeling in vitro. CNC/SF hydrogels with BMSCs degraded more quickly than the acellular hydrogels as reflected by the MR relaxation rate trends in vivo. The morphology of neocartilage was noninvasively visualized by the three-dimensional water-selective cartilage MRI scan sequence, and the cartilage repair was further demonstrated by macroscopic and histological observations. Conclusion: This USPIO-labeled CNC/SF hydrogel system provides a new perspective on image-guided tissue engineering for cartilage regeneration. PMID:29464005

  10. Preparation of supramolecular hydrogel-enzyme hybrids exhibiting biomolecule-responsive gel degradation.

    Science.gov (United States)

    Shigemitsu, Hajime; Fujisaku, Takahiro; Onogi, Shoji; Yoshii, Tatsuyuki; Ikeda, Masato; Hamachi, Itaru

    2016-09-01

    Hydrogelators are small, self-assembling molecules that form supramolecular nanofiber networks that exhibit unique dynamic properties. Development of supramolecular hydrogels that degrade in response to various biomolecules could potentially be used for applications in areas such as drug delivery and diagnostics. Here we provide a synthetic procedure for preparing redox-responsive supramolecular hydrogelators that are used to create hydrogels that degrade in response to oxidizing or reducing conditions. The synthesis takes ∼2-4 d, and it can potentially be carried out in parallel to prepare multiple hydrogelator candidates. This described solid-phase peptide synthesis protocol can be used to produce previously described hydrogelators or to construct a focused molecular library to efficiently discover and optimize new hydrogelators. In addition, we describe the preparation of redox-responsive supramolecular hydrogel-enzyme hybrids that are created by mixing aqueous solutions of hydrogelators and enzymes, which requires 2 h for completion. The resultant supramolecular hydrogel-enzyme hybrids exhibit gel degradation in response to various biomolecules, and can be rationally designed by connecting the chemical reactions of the hydrogelators with enzymatic reactions. Gel degradation in response to biomolecules as triggers occurs within a few hours. We also describe the preparation of hydrogel-enzyme hybrids arrayed on flat glass slides, enabling high-throughput analysis of biomolecules such as glucose, uric acid, lactate and so on by gel degradation, which is detectable by the naked eye. The protocol requires ∼6 h to prepare the hydrogel-enzyme hybrid array and to complete the biomolecule assay.

  11. Injectable, Biomolecule-Responsive Polypeptide Hydrogels for Cell Encapsulation and Facile Cell Recovery through Triggered Degradation.

    Science.gov (United States)

    Xu, Qinghua; He, Chaoliang; Zhang, Zhen; Ren, Kaixuan; Chen, Xuesi

    2016-11-16

    Injectable hydrogels have been widely investigated in biomedical applications, and increasing demand has been proposed to achieve dynamic regulation of physiological properties of hydrogels. Herein, a new type of injectable and biomolecule-responsive hydrogel based on poly(l-glutamic acid) (PLG) grafted with disulfide bond-modified phloretic acid (denoted as PLG-g-CPA) was developed. The hydrogels formed in situ via enzymatic cross-linking under physiological conditions in the presence of horseradish peroxidase and hydrogen peroxide. The physiochemical properties of the hydrogels, including gelation time and the rheological property, were measured. Particularly, the triggered degradation of the hydrogel in response to a reductive biomolecule, glutathione (GSH), was investigated in detail. The mechanical strength and inner porous structure of the hydrogel were influenced by the addition of GSH. The polypeptide hydrogel was used as a three-dimensional (3D) platform for cell encapsulation, which could release the cells through triggered disruption of the hydrogel in response to the addition of GSH. The cells released from the hydrogel were found to maintain high viability. Moreover, after subcutaneous injection into rats, the PLG-g-CPA hydrogels with disulfide-containing cross-links exhibited a markedly faster degradation behavior in vivo compared to that of the PLG hydrogels without disulfide cross-links, implying an interesting accelerated degradation process of the disulfide-containing polypeptide hydrogels in the physiological environment in vivo. Overall, the injectable and biomolecule-responsive polypeptide hydrogels may serve as a potential platform for 3D cell culture and easy cell collection.

  12. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    Directory of Open Access Journals (Sweden)

    Song Bao

    Full Text Available Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1. The hydrogel also exhibited higher separation selectivity to Pb(2+ than Cu(2+. The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.

  13. Heparin-based hydrogels with tunable sulfation & degradation for anti-inflammatory small molecule delivery.

    Science.gov (United States)

    Peng, Yifeng; Tellier, Liane E; Temenoff, Johnna S

    2016-08-16

    Sustained release of anti-inflammatory agents remains challenging for small molecule drugs due to their low molecular weight and hydrophobicity. Therefore, the goal of this study was to control the release of a small molecule anti-inflammatory agent, crystal violet (CV), from hydrogels fabricated with heparin, a highly sulfated glycosaminoglycan capable of binding positively-charged molecules such as CV. In this system, both electrostatic interactions between heparin and CV and hydrogel degradation were tuned simultaneously by varying the level of heparin sulfation and varying the amount of dithiothreitol within hydrogels, respectively. It was found that heparin sulfation significantly affected CV release, whereby more sulfated heparin hydrogels (Hep and Hep(-N)) released CV with near zero-order release kinetics (R-squared values between 0.96-0.99). Furthermore, CV was released more quickly from fast-degrading hydrogels than slow-degrading hydrogels, providing a method to tune total CV release between 5-15 days while maintaining linear release kinetics. In particular, N-desulfated heparin hydrogels exhibited efficient CV loading (∼90% of originally included CV), near zero-order CV release kinetics, and maintenance of CV bioactivity after release, making this hydrogel formulation a promising CV delivery vehicle for a wide range of inflammatory diseases.

  14. Microsphere erosion in outer hydrogel membranes creating macroscopic porosity to counter biofouling-induced sensor degradation.

    Science.gov (United States)

    Vaddiraju, S; Wang, Y; Qiang, L; Burgess, D J; Papadimitrakopoulos, F

    2012-10-16

    Biofouling and tissue inflammation present major challenges toward the realization of long-term implantable glucose sensors. Following sensor implantation, proteins and cells adsorb on sensor surfaces to not only inhibit glucose flux but also signal a cascade of inflammatory events that eventually lead to permeability-reducing fibrotic encapsulation. The use of drug-eluting hydrogels as outer sensor coatings has shown considerable promise to mitigate these problems via the localized delivery of tissue response modifiers to suppress inflammation and fibrosis, along with reducing protein and cell absorption. Biodegradable poly (lactic-co-glycolic) acid (PLGA) microspheres, encapsulated within a poly (vinyl alcohol) (PVA) hydrogel matrix, present a model coating where the localized delivery of the potent anti-inflammatory drug dexamethasone has been shown to suppress inflammation over a period of 1-3 months. Here, it is shown that the degradation of the PLGA microspheres provides an auxiliary venue to offset the negative effects of protein adsorption. This was realized by: (1) the creation of fresh porosity within the PVA hydrogel following microsphere degradation (which is sustained until the complete microsphere degradation) and (2) rigidification of the PVA hydrogel to prevent its complete collapse onto the newly created void space. Incubation of the coated sensors in phosphate buffered saline (PBS) led to a monotonic increase in glucose permeability (50%), with a corresponding enhancement in sensor sensitivity over a 1 month period. Incubation in serum resulted in biofouling and consequent clogging of the hydrogel microporosity. This, however, was partially offset by the generated macroscopic porosity following microsphere degradation. As a result of this, a 2-fold recovery in sensor sensitivity for devices with microsphere/hydrogel composite coatings was observed as opposed to similar devices with blank hydrogel coatings. These findings suggest that the use of

  15. Kinetic Degradation and Controlled Drug Delivery System Studies for Sensitive Hydrogels Prepared by Gamma Irradiation

    International Nuclear Information System (INIS)

    Eid, M.; El-Arnaouty, M.B.

    2008-01-01

    Ternary mixtures of N-vinyle-2-pyrrolidone(NVP ), itaconic acid (IA) and gelatin (G) were gamma irradiated to prepared poly(NVP/IA/G) hydrogels. The equilibrium kinetic swelling, drug release behavior, Scan Electron Microscope (SEM) and the swelling-degradation kinetics were studied. Both the diffusion exponent and the diffusion coefficient increase with increasing content of (IA). Also, the swelling behavior of copolymer hydrogels in response to ph value of the external media was studied, it is noted that the highest swelling values at ph 4. The in vitro drug release behavior of these hydrogels was examined by quantification analysis with a UV/VIS spectrophotometers. Chlorpromazine hydrochloride was loaded into dried hydrogels to investigate the stimuli-sensitive property at the specific ph. The release studies show that the highest value of release was at ph 4 which can be used for drug delivery system

  16. Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

    Science.gov (United States)

    Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

    2018-01-01

    Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

  17. Degradation-mediated cellular traction directs stem cell fate in covalently crosslinked three-dimensional hydrogels

    Science.gov (United States)

    Khetan, Sudhir; Guvendiren, Murat; Legant, Wesley R.; Cohen, Daniel M.; Chen, Christopher S.; Burdick, Jason A.

    2013-05-01

    Although cell-matrix adhesive interactions are known to regulate stem cell differentiation, the underlying mechanisms, in particular for direct three-dimensional encapsulation within hydrogels, are poorly understood. Here, we demonstrate that in covalently crosslinked hyaluronic acid (HA) hydrogels, the differentiation of human mesenchymal stem cells (hMSCs) is directed by the generation of degradation-mediated cellular traction, independently of cell morphology or matrix mechanics. hMSCs within HA hydrogels of equivalent elastic moduli that permit (restrict) cell-mediated degradation exhibited high (low) degrees of cell spreading and high (low) tractions, and favoured osteogenesis (adipogenesis). Moreover, switching the permissive hydrogel to a restrictive state through delayed secondary crosslinking reduced further hydrogel degradation, suppressed traction, and caused a switch from osteogenesis to adipogenesis in the absence of changes to the extended cellular morphology. Furthermore, inhibiting tension-mediated signalling in the permissive environment mirrored the effects of delayed secondary crosslinking, whereas upregulating tension induced osteogenesis even in the restrictive environment.

  18. Poly(amido-amine)-based hydrogels with tailored mechanical properties and degradation rates for tissue engineering.

    Science.gov (United States)

    Martello, Federico; Tocchio, Alessandro; Tamplenizza, Margherita; Gerges, Irini; Pistis, Valentina; Recenti, Rossella; Bortolin, Monica; Del Fabbro, Massimo; Argentiere, Simona; Milani, Paolo; Lenardi, Cristina

    2014-03-01

    Poly(amido-amine) (PAA) hydrogels containing the 2,2-bisacrylamidoacetic acid-4-amminobutyl guanidine monomeric unit have a known ability to enhance cellular adhesion by interacting with the arginin-glycin-aspartic acid (RGD)-binding αVβ3 integrin, expressed by a wide number of cell types. Scientific interest in this class of materials has traditionally been hampered by their poor mechanical properties and restricted range of degradation rate. Here we present the design of novel biocompatible, RGD-mimic PAA-based hydrogels with wide and tunable degradation rates as well as improved mechanical and biological properties for biomedical applications. This is achieved by radical polymerization of acrylamide-terminated PAA oligomers in both the presence and absence of 2-hydroxyethylmethacrylate. The degradation rate is found to be precisely tunable by adjusting the PAA oligomer molecular weight and acrylic co-monomer concentration in the starting reaction mixture. Cell adhesion and proliferation tests on Madin-Darby canine kidney epithelial cells show that PAA-based hydrogels have the capacity to promote cell adhesion up to 200% compared to the control. Mechanical tests show higher compressive strength of acrylic chain containing hydrogels compared to traditional PAA hydrogels. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Degradation Behaviour of Gamma Irradiated Poly(Acrylic Acid)-graft-Chitosan Superabsorbent Hydrogel

    Science.gov (United States)

    Ria Barleany, Dhena; Ilhami, Alpin; Yusuf Yudanto, Dea; Erizal

    2018-03-01

    A series of superabsorbent hydrogels were prepared from chitosan and partially neutralized acrylic acid at room temperature by gamma irradiation technique. The effect of irradiation and chitosan addition to the degradation behaviour of polymer were investigated. The gel content, swelling capacity, Equillibrium Degree of Swelling (EDS), Fourier Transform Infra Red (FTIR), and Scanning Electron Microscopy (SEM) study were also performed. Natural degradation in soil and thermal degradation by using of TGA analysis were observed. The variation of chitosan compositions were 0.5, 1, 1.5, and 2 g and the total irradiation doses were 5, 10, 15, and 20 kGy. The highest water capacity of 583.3 g water/g dry hydrogel was resulted from 5 kGy total irradiation dose and 0,5 g addition of chitosan. From the thermal degradation evaluation by using of TGA analysis showed that irradiation dose did not give a significant influence to the degradation rate. The rate of thermal degradation was ranged between 2.42 to 2.55 mg/min. In the natural test of degradation behaviour by using of soil medium, the hydrogel product with chitosan addition was found to have better degradability compared with the poly(acrylic acid) polymer without chitosan.

  20. Injectable, degradable, electroactive nanocomposite hydrogels containing conductive polymer nanoparticles for biomedical applications

    Directory of Open Access Journals (Sweden)

    Wang QM

    2016-01-01

    Full Text Available Qinmei Wang,1 Qiong Wang,2 Wei Teng2 1Laboratory of Biomaterials, Key Laboratory on Assisted Circulation, Ministry of Health, Cardiovascular Division, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, People’s Republic of China; 2Department of Prosthodontics, Hospital of Stomatology, Institute of Stomatological Research, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, People’s Republic of China Abstract: Injectable electroactive hydrogels (eGels are promising in regenerative medicine and drug delivery, however, it is still a challenge to obtain such hydrogels simultaneously possessing other properties including uniform structure, degradability, robustness, and biocompatibility. An emerging strategy to endow hydrogels with desirable properties is to incorporate functional nanoparticles in their network. Herein, we report the synthesis and characterization of an injectable hydrogel based on oxidized alginate (OA crosslinking gelatin reinforced by electroactive tetraaniline-graft-OA nanoparticles (nEOAs, where nEOAs are expected to impart electroactivity besides reinforcement without significantly degrading the other properties of hydrogels. Assays of transmission electron microscopy, 1H nuclear magnetic resonance, and dynamic light scattering reveal that EOA can spontaneously and quickly self-assemble into robust nanoparticles in water, and this nanoparticle structure can be kept at pH 3~9. Measurement of the gel time by rheometer and the stir bar method confirms the formation of the eGels, and their gel time is dependent on the weight content of nEOAs. As expected, adding nEOAs to hydrogels does not cause the phase separation (scanning electron microscopy observation, but it improves mechanical strength up to ~8 kPa and conductivity up to ~10-6 S/cm in our studied range. Incubating eGels in phosphate-buffered saline leads to their further swelling with an increase of water content <6% and gradual degradation

  1. Stereolithographic printing of ionically-crosslinked alginate hydrogels for degradable biomaterials and microfluidics.

    Science.gov (United States)

    Valentin, Thomas M; Leggett, Susan E; Chen, Po-Yen; Sodhi, Jaskiranjeet K; Stephens, Lauren H; McClintock, Hayley D; Sim, Jea Yun; Wong, Ian Y

    2017-10-11

    3D printed biomaterials with spatial and temporal functionality could enable interfacial manipulation of fluid flows and motile cells. However, such dynamic biomaterials are challenging to implement since they must be responsive to multiple, biocompatible stimuli. Here, we show stereolithographic printing of hydrogels using noncovalent (ionic) crosslinking, which enables reversible patterning with controlled degradation. We demonstrate this approach using sodium alginate, photoacid generators and various combinations of divalent cation salts, which can be used to tune the hydrogel degradation kinetics, pattern fidelity, and mechanical properties. This approach is first utilized to template perfusable microfluidic channels within a second encapsulating hydrogel for T-junction and gradient devices. The presence and degradation of printed alginate microstructures were further verified to have minimal toxicity on epithelial cells. Degradable alginate barriers were used to direct collective cell migration from different initial geometries, revealing differences in front speed and leader cell formation. Overall, this demonstration of light-based 3D printing using non-covalent crosslinking may enable adaptive and stimuli-responsive biomaterials, which could be utilized for bio-inspired sensing, actuation, drug delivery, and tissue engineering.

  2. Injectable, degradable, electroactive nanocomposite hydrogels containing conductive polymer nanoparticles for biomedical applications.

    Science.gov (United States)

    Wang, Qinmei; Wang, Qiong; Teng, Wei

    2016-01-01

    Injectable electroactive hydrogels (eGels) are promising in regenerative medicine and drug delivery, however, it is still a challenge to obtain such hydrogels simultaneously possessing other properties including uniform structure, degradability, robustness, and biocompatibility. An emerging strategy to endow hydrogels with desirable properties is to incorporate functional nanoparticles in their network. Herein, we report the synthesis and characterization of an injectable hydrogel based on oxidized alginate (OA) crosslinking gelatin reinforced by electroactive tetraaniline-graft-OA nanoparticles (nEOAs), where nEOAs are expected to impart electroactivity besides reinforcement without significantly degrading the other properties of hydrogels. Assays of transmission electron microscopy, (1)H nuclear magnetic resonance, and dynamic light scattering reveal that EOA can spontaneously and quickly self-assemble into robust nanoparticles in water, and this nanoparticle structure can be kept at pH 3~9. Measurement of the gel time by rheometer and the stir bar method confirms the formation of the eGels, and their gel time is dependent on the weight content of nEOAs. As expected, adding nEOAs to hydrogels does not cause the phase separation (scanning electron microscopy observation), but it improves mechanical strength up to ~8 kPa and conductivity up to ~10(-6) S/cm in our studied range. Incubating eGels in phosphate-buffered saline leads to their further swelling with an increase of water content <6% and gradual degradation. When growing mesenchymal stem cells on eGels with nEOA content ≤14%, the growth curves and morphology of cells were found to be similar to that on tissue culture plastic; when implanting these eGels on a chick chorioallantoic membrane for 1 week, mild inflammation response appeared without any other structural changes, indicating their good in vitro and in vivo biocompatibility. With injectability, uniformity, degradability, electroactivity, relative

  3. Balancing Cell Migration with Matrix Degradation Enhances Gene Delivery to Cells Cultured Three-Dimensionally Within Hydrogels

    Science.gov (United States)

    Shepard, Jaclyn A.; Huang, Alyssa; Shikanova, Ariella; Shea, Lonnie D.

    2010-01-01

    In regenerative medicine, hydrogels are employed to fill defects and support the infiltration of cells that can ultimately regenerate tissue. Gene delivery within hydrogels targeting infiltrating cells has the potential to promote tissue formation, but the delivery efficiency of nonviral vectors within hydrogels is low hindering their applicability in tissue regeneration. To improve their functionality, we have conducted a mechanistic study to investigate the contribution of cell migration and matrix degradation on gene delivery. In this report, lipoplexes were entrapped within hydrogels based on poly(ethylene glycol) (PEG) crosslinked with peptides containing matrix metalloproteinase degradable sequences. The mesh size of these hydrogels is substantially less than the size of the entrapped lipoplexes, which can function to retain vectors. Cell migration and transfection were simultaneously measured within hydrogels with varying density of cell adhesion sites (Arg-Gly-Asp peptides) and solids content. Increasing RGD density increased expression levels up to 100-fold, while greater solids content sustained expression levels for 16 days. Increasing RGD density and decreasing solids content increased cell migration, which indicates expression levels increase with increased cell migration. Initially exposing cells to vector resulted in transient expression that declined after 2 days, verifying the requirement of migration to sustain expression. Transfected cells were predominantly located within the population of migrating cells for hydrogels that supported cell migration. Although the small mesh size retained at least 70% of the lipoplexes in the absence of cells after 32 days, the presence of cells decreased retention to 10% after 16 days. These results indicate that vectors retained within hydrogels contact migrating cells, and that persistent cell migration can maintain elevated expression levels. Thus matrix degradation and cell migration are fundamental design

  4. Nondestructive evaluation of a new hydrolytically degradable and photo-clickable PEG hydrogel for cartilage tissue engineering.

    Science.gov (United States)

    Neumann, Alexander J; Quinn, Timothy; Bryant, Stephanie J

    2016-07-15

    Photopolymerizable and hydrolytically labile poly(ethylene glycol) (PEG) hydrogels formed from photo-clickable reactions were investigated as cell delivery platforms for cartilage tissue engineering (TE). PEG hydrogels were formed from thiol-norbornene PEG macromers whereby the crosslinks contained caprolactone segments with hydrolytically labile ester linkages. Juvenile bovine chondrocytes encapsulated in the hydrogels were cultured for up to four weeks and assessed biochemically and histologically, using standard destructive assays, and for mechanical and ultrasound properties, as nondestructive assays. Bulk degradation of acellular hydrogels was confirmed by a decrease in compressive modulus and an increase in mass swelling ratio over time. Chondrocytes deposited increasing amounts of sulfated glycosaminoglycans and collagens in the hydrogels with time. Spatially, collagen type II and aggrecan were present in the neotissue with formation of a territorial matrix beginning at day 21. Nondestructive measurements revealed an 8-fold increase in compressive modulus from days 7 to 28, which correlated with total collagen content. Ultrasound measurements revealed changes in the constructs over time, which differed from the mechanical properties, and appeared to correlate with ECM structure and organization shown by immunohistochemical analysis. Overall, non-destructive and destructive measurements show that this new hydrolytically degradable PEG hydrogel is promising for cartilage TE. Designing synthetic hydrogels whose degradation matches tissue growth is critical to maintaining mechanical integrity as the hydrogel degrades and new tissue forms, but is challenging due to the nature of the hydrogel crosslinks that inhibit diffusion of tissue matrix molecules. This study details a promising, new, photo-clickable and synthetic hydrogel whose degradation supports cartilaginous tissue matrix growth leading to the formation of a territorial matrix, concomitant with an

  5. Combining a hydrogel and an electrochemical biosensor to determine the extent of degradation of paper artworks.

    Science.gov (United States)

    Micheli, Laura; Mazzuca, Claudia; Palleschi, Antonio; Palleschi, Giuseppe

    2012-06-01

    Paper-based artworks are among the most valuable assets for transmission of knowledge. Historical paper is composed of different polysaccharides (e.g. cellulose), binders, and glues. During aging all of these components undergo several degradation processes, as a result of external and intrinsic causes, and these can compromise the state of conservation of the document. In this work, application of a new biotechnological strategy for paper artefact preservation is reported. By making use of innovative and non-invasive materials, for example appropriate hydrogels, in combination with selective electrochemical biosensors, it is possible to simultaneously verify the degradation condition of the paper artwork and then to efficiently clean it, while monitoring the process of removal of both pollution and degradation products. In this paper, we focus on specific examples in which such techniques have been applied to paper artworks and that illustrate the advantages and potential of this biotechnology compared with the traditional paper-cleaning methods currently in use.

  6. Poly(ethylene glycol) (PEG)-lactic acid nanocarrier-based degradable hydrogels for restoring the vaginal microenvironment

    Science.gov (United States)

    Rajan, Sujata Sundara; Turovskiy, Yevgeniy; Singh, Yashveer; Chikindas, Michael L.; Sinko, Patrick J.

    2014-01-01

    Women with bacterial vaginosis (BV) display reduced vaginal acidity, which make them susceptible to associated infections such as HIV. In the current study, poly(ethylene glycol) (PEG) nanocarrier-based degradable hydrogels were developed for the controlled release of lactic acid in the vagina of BV-infected women. PEG-lactic acid (PEG-LA) nanocarriers were prepared by covalently attaching lactic acid to 8-arm PEG-SH via cleavable thioester bonds. PEG-LA nanocarriers with 4 copies of lactic acid per molecule provided controlled release of lactic acid with a maximum release of 23% and 47% bound lactic acid in phosphate buffered saline (PBS, pH 7.4) and acetate buffer (AB, pH 4.3), respectively. The PEG nanocarrier-based hydrogels were formed by cross-linking the PEG-LA nanocarriers with 4-arm PEG-NHS via degradable thioester bonds. The nanocarrier-based hydrogels formed within 20 min under ambient conditions and exhibited an elastic modulus that was 100-fold higher than the viscous modulus. The nanocarrier-based degradable hydrogels provided controlled release of lactic acid for several hours; however, a maximum release of only 10%–14% bound lactic acid was observed possibly due to steric hindrance of the polymer chains in the cross-linked hydrogel. In contrast, hydrogels with passively entrapped lactic acid showed burst release with complete release within 30 min. Lactic acid showed antimicrobial activity against the primary BV pathogen Gardnerella vaginalis with a minimum inhibitory concentration (MIC) of 3.6 mg/ml. In addition, the hydrogels with passively entrapped lactic acid showed retained antimicrobial activity with complete inhibition G. vaginalis growth within 48 h. The results of the current study collectively demonstrate the potential of PEG nanocarrier-based hydrogels for vaginal administration of lactic acid for preventing and treating BV. PMID:25223229

  7. A novel reducing graphene/polyaniline/cuprous oxide composite hydrogel with unexpected photocatalytic activity for the degradation of Congo red

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Jie; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Cao, Juan; Shen, Yuhua, E-mail: yhshen@ahu.edu.cn

    2016-01-01

    Graphical abstract: Excellent photocatalytic activity of the RGO/PANI/Cu{sub 2}O composite hydrogel for CR degradation under UV–vis light irradiation. - Highlights: • The RGO/PANI/Cu{sub 2}O composite hydrogel was first synthesized via a facile method. • Photocatalytic performance was studied under UV–vis light. • The ternary composite hydrogel shows unexpected photocatalytic activity. • A possible photocatalysis mechanism was illustrated. - Abstract: In this work, a novel reducing graphene/polyaniline/cuprous oxide (RGO/PANI/Cu{sub 2}O) composite hydrogel with a 3D porous network has been successfully prepared via a one-pot method in the presence of cubic Cu{sub 2}O nanoparticles. The as-synthesized ternary composites hydrogel shows unexpected photocatalytic activity such that Congo red (CR) degradation efficiency can reaches 97.91% in 20 min under UV–vis light irradiation, which is much higher than that of either the single component (Cu{sub 2}O nanoparticles), or two component systems (RGO/Cu{sub 2}O composite hydrogel and PANI/Cu{sub 2}O nanocomposites). Furthermore, the ternary composite hydrogel exhibits high stability and do not show any significant loss after five recycles. Such outstanding photocatalytic activity of the RGO/PANI/Cu{sub 2}O composite hydrogel was ascribed to the high absorption ability of the product for CR and the synergic effect among RGO, PANI and Cu{sub 2}O in photocatalytic process. The product of this work would provide a new sight for the construction of UV–vis light responsive photocatalyst with high performance.

  8. A novel reducing graphene/polyaniline/cuprous oxide composite hydrogel with unexpected photocatalytic activity for the degradation of Congo red

    International Nuclear Information System (INIS)

    Miao, Jie; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Cao, Juan; Shen, Yuhua

    2016-01-01

    Graphical abstract: Excellent photocatalytic activity of the RGO/PANI/Cu_2O composite hydrogel for CR degradation under UV–vis light irradiation. - Highlights: • The RGO/PANI/Cu_2O composite hydrogel was first synthesized via a facile method. • Photocatalytic performance was studied under UV–vis light. • The ternary composite hydrogel shows unexpected photocatalytic activity. • A possible photocatalysis mechanism was illustrated. - Abstract: In this work, a novel reducing graphene/polyaniline/cuprous oxide (RGO/PANI/Cu_2O) composite hydrogel with a 3D porous network has been successfully prepared via a one-pot method in the presence of cubic Cu_2O nanoparticles. The as-synthesized ternary composites hydrogel shows unexpected photocatalytic activity such that Congo red (CR) degradation efficiency can reaches 97.91% in 20 min under UV–vis light irradiation, which is much higher than that of either the single component (Cu_2O nanoparticles), or two component systems (RGO/Cu_2O composite hydrogel and PANI/Cu_2O nanocomposites). Furthermore, the ternary composite hydrogel exhibits high stability and do not show any significant loss after five recycles. Such outstanding photocatalytic activity of the RGO/PANI/Cu_2O composite hydrogel was ascribed to the high absorption ability of the product for CR and the synergic effect among RGO, PANI and Cu_2O in photocatalytic process. The product of this work would provide a new sight for the construction of UV–vis light responsive photocatalyst with high performance.

  9. Influence of Aloe vera on water absorption and enzymatic in vitro degradation of alginate hydrogel films.

    Science.gov (United States)

    Pereira, Rúben F; Carvalho, Anabela; Gil, M H; Mendes, Ausenda; Bártolo, Paulo J

    2013-10-15

    This study investigates the influence of Aloe vera on water absorption and the in vitro degradation rate of Aloe vera-Ca-alginate hydrogel films, for wound healing and drug delivery applications. The influence of A. vera content (5%, 15% and 25%, v/v) on water absorption was evaluated by the incubation of the films into a 0.1 M HCl solution (pH 1.0), acetate buffer (pH 5.5) and simulated body fluid solution (pH 7.4) during 24h. Results show that the water absorption is significantly higher for films containing high A. vera contents (15% and 25%), while no significant differences are observed between the alginate neat film and the film with 5% of A. vera. The in vitro enzymatic degradation tests indicate that an increase in the A. vera content significantly enhances the degradation rate of the films. Control films, incubated in a simulated body fluid solution without enzymes, are resistant to the hydrolytic degradation, exhibiting reduced weight loss and maintaining its structural integrity. Results also show that the water absorption and the in vitro degradation rate of the films can be tailored by changing the A. vera content. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Promoted Chondrogenesis of Cocultured Chondrocytes and Mesenchymal Stem Cells under Hypoxia Using In-situ Forming Degradable Hydrogel Scaffolds

    NARCIS (Netherlands)

    Huang, Xiaobin; Hou, Yong; Zhong, Leilei; Huang, Dechun; Qian, Hongliang; Karperien, Marcel; Chen, Wei

    2018-01-01

    We investigated the effects of different oxygen tension (21% and 2.5% O2) on the chondrogenesis of different cell systems cultured in pH-degradable PVA hydrogels, including human articular chondrocytes (hACs), human mesenchymal stem cells (hMSCs), and their cocultures with a hAC/hMSC ratio of 20/80.

  11. Integrating valve-inspired design features into poly(ethylene glycol) hydrogel scaffolds for heart valve tissue engineering.

    Science.gov (United States)

    Zhang, Xing; Xu, Bin; Puperi, Daniel S; Yonezawa, Aline L; Wu, Yan; Tseng, Hubert; Cuchiara, Maude L; West, Jennifer L; Grande-Allen, K Jane

    2015-03-01

    The development of advanced scaffolds that recapitulate the anisotropic mechanical behavior and biological functions of the extracellular matrix in leaflets would be transformative for heart valve tissue engineering. In this study, anisotropic mechanical properties were established in poly(ethylene glycol) (PEG) hydrogels by crosslinking stripes of 3.4 kDa PEG diacrylate (PEGDA) within 20 kDa PEGDA base hydrogels using a photolithographic patterning method. Varying the stripe width and spacing resulted in a tensile elastic modulus parallel to the stripes that was 4.1-6.8 times greater than that in the perpendicular direction, comparable to the degree of anisotropy between the circumferential and radial orientations in native valve leaflets. Biomimetic PEG-peptide hydrogels were prepared by tethering the cell-adhesive peptide RGDS and incorporating the collagenase-degradable peptide PQ (GGGPQG↓IWGQGK) into the polymer network. The specific amounts of RGDS and PEG-PQ within the resulting hydrogels influenced the elongation, de novo extracellular matrix deposition and hydrogel degradation behavior of encapsulated valvular interstitial cells (VICs). In addition, the morphology and activation of VICs grown atop PEG hydrogels could be modulated by controlling the concentration or micro-patterning profile of PEG-RGDS. These results are promising for the fabrication of PEG-based hydrogels using anatomically and biologically inspired scaffold design features for heart valve tissue engineering. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. On the role of hydrogel structure and degradation in controlling the transport of cell-secreted matrix molecules for engineered cartilage.

    Science.gov (United States)

    Dhote, Valentin; Skaalure, Stacey; Akalp, Umut; Roberts, Justine; Bryant, Stephanie J; Vernerey, Franck J

    2013-03-01

    Damage to cartilage caused by injury or disease can lead to pain and loss of mobility, diminishing one's quality of life. Because cartilage has a limited capacity for self-repair, tissue engineering strategies, such as cells encapsulated in synthetic hydrogels, are being investigated as a means to restore the damaged cartilage. However, strategies to date are suboptimal in part because designing degradable hydrogels is complicated by structural and temporal complexities of the gel and evolving tissue along multiple length scales. To address this problem, this study proposes a multi-scale mechanical model using a triphasic formulation (solid, fluid, unbound matrix molecules) based on a single chondrocyte releasing extracellular matrix molecules within a degrading hydrogel. This model describes the key players (cells, proteoglycans, collagen) of the biological system within the hydrogel encompassing different length scales. Two mechanisms are included: temporal changes of bulk properties due to hydrogel degradation, and matrix transport. Numerical results demonstrate that the temporal change of bulk properties is a decisive factor in the diffusion of unbound matrix molecules through the hydrogel. Transport of matrix molecules in the hydrogel contributes both to the development of the pericellular matrix and the extracellular matrix and is dependent on the relative size of matrix molecules and the hydrogel mesh. The numerical results also demonstrate that osmotic pressure, which leads to changes in mesh size, is a key parameter for achieving a larger diffusivity for matrix molecules in the hydrogel. The numerical model is confirmed with experimental results of matrix synthesis by chondrocytes in biodegradable poly(ethylene glycol)-based hydrogels. This model may ultimately be used to predict key hydrogel design parameters towards achieving optimal cartilage growth. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels for pH-sensitive photocatalytic degradation of organic pollutants

    International Nuclear Information System (INIS)

    Moon, Young-E; Jung, Gowun; Yun, Jumi; Kim, Hyung-Il

    2013-01-01

    Graphical abstract: The photocatalytic removal of pollutants was improved by the two-step mechanism based on the adsorption of pollutants by hydrogel and the effective decomposition by combination of TiO 2 and graphene oxide. -- Highlights: • pH sensitive PVA/PAAc hydrogels were prepared by radical polymerization and condensation reaction. • PVA/PAAc/TiO 2 /graphene oxide nanocomposite hydrogels were used for treatment of basic waste water. • Photocatalytic acitivity of TiO 2 was improved by incorporation of graphene oxide. • Photocatalytic decomposition by nanocomposite hydrogel was improved by increasing pH. -- Abstract: Poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were prepared using radical polymerization and condensation reaction for the photocatalytic treatment of waste water. Graphene oxide was used as an additive to improve the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 nanocomposite hydrogels. Both TiO 2 and graphene oxide were immobilized in poly(vinyl alcohol)/poly(acrylic acid) hydrogel matrix for an easier recovery after the waste water treatment. The photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer. The improved removal of pollutants was due to the two-step mechanism based on the adsorption of pollutants by nanocomposite hydrogel and the effective decomposition of pollutants by TiO 2 and graphene oxide. The highest swelling of nanocomposite hydrogel was observed at pH 10 indicating that poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were suitable as a promising system for the treatment of basic waste water

  14. pH-responsive and enzymatically-responsive hydrogel microparticles for the oral delivery of therapeutic proteins: Effects of protein size, crosslinking density, and hydrogel degradation on protein delivery.

    Science.gov (United States)

    Koetting, Michael Clinton; Guido, Joseph Frank; Gupta, Malvika; Zhang, Annie; Peppas, Nicholas A

    2016-01-10

    Two potential platform technologies for the oral delivery of protein therapeutics were synthesized and tested. pH-responsive poly(itaconic acid-co-N-vinyl-2-pyrrolidone) (P(IA-co-NVP)) hydrogel microparticles were tested in vitro with model proteins salmon calcitonin, urokinase, and rituximab to determine the effects of particle size, protein size, and crosslinking density on oral delivery capability. Particle size showed no significant effect on overall delivery potential but did improve percent release of encapsulated protein over the micro-scale particle size range studied. Protein size was shown to have a significant impact on the delivery capability of the P(IA-co-NVP) hydrogel. We show that when using P(IA-co-NVP) hydrogel microparticles with 3 mol% tetra(ethylene glycol) dimethacrylate crosslinker, a small polypeptide (salmon calcitonin) loads and releases up to 45 μg/mg hydrogel while the mid-sized protein urokinase and large monoclonal antibody rituximab load and release only 19 and 24 μg/mg hydrogel, respectively. We further demonstrate that crosslinking density offers a simple method for tuning hydrogel properties to variously sized proteins. Using 5 mol% TEGDMA crosslinker offers optimal performance for the small peptide, salmon calcitonin, whereas lower crosslinking density of 1 mol% offers optimal performance for the much larger protein rituximab. Finally, an enzymatically-degradable hydrogels of P(MAA-co-NVP) crosslinked with the peptide sequence MMRRRKK were synthesized and tested in simulated gastric and intestinal conditions. These hydrogels offer ideal loading and release behavior, showing no degradative release of encapsulated salmon calcitonin in gastric conditions while yielding rapid and complete release of encapsulated protein within 1h in intestinal conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Formation of model hepatocellular aggregates in a hydrogel scaffold using degradable genipin crosslinked gelatin microspheres as cell carriers

    International Nuclear Information System (INIS)

    Lau, Ting Ting; Lee, Li Qi Priscilyn; Leong, Wenyan; Wang, Dong-An

    2012-01-01

    Primary hepatocyte is probably the preferred cell for cell therapy in liver regeneration. However, its non-ideal proliferation capacity and rapid loss of phenotype during 2D culture compromises the quality and quantity of the transplanted hepatocytes, resulting in variable success rates of this treatment. Many studies have shown that the formation of 3D hepatocellular spheroids aids in the maintenance of liver-specific functions in hepatocytes. However, many of the methodologies employed require a sophisticated set-up or specialized equipment which makes it uneconomical to scale up for clinical applications. In this study, we have developed dual-functioning genipin crosslinked gelatin microspheres that serve as cell carriers as well as porogens for delivering the model cells and also for creating cavities. The cells were first seeded onto genipin crosslinked gelatin microspheres for attachment, followed by encapsulation in alginate hydrogel. Collagenase, MMP-9, was introduced either in the culture media or mixed with alginate precursor solution to allow microsphere degradation for creating cavities within the gel bulk. Accordingly, the cells proliferate within the cavities, forming hepatocellular aggregates while the alginate hydrogel serves as a confinement, restricting the size and the shape of the aggregates to the size of the cavities. In addition, the final hepatocellular aggregates could be harvested from the system by removing the alginate hydrogel via citrate treatment. Therefore, this versatile platform not only has the advantage of injectability and simplicity, the cellular aggregates generated are in a controlled size and shape and can be extracted from the system. (paper)

  16. Intracellular degradation of microspheres based on cross-linked dextran hydrogels or amphiphilic block copolymers: A comparative Raman microscopy study

    Science.gov (United States)

    van Manen, Henk-Jan; van Apeldoorn, Aart A; Verrijk, Ruud; van Blitterswijk, Clemens A; Otto, Cees

    2007-01-01

    Micro- and nanospheres composed of biodegradable polymers show promise as versatile devices for the controlled delivery of biopharmaceuticals. Whereas important properties such as drug release profiles, biocompatibility, and (bio)degradability have been determined for many types of biodegradable particles, information about particle degradation inside phagocytic cells is usually lacking. Here, we report the use of confocal Raman microscopy to obtain chemical information about cross-linked dextran hydrogel microspheres and amphiphilic poly(ethylene glycol)-terephthalate/poly(butylene terephthalate) (PEGT/PBT) microspheres inside RAW 264.7 macrophage phagosomes. Using quantitative Raman microspectroscopy, we show that the dextran concentration inside phagocytosed dextran microspheres decreases with cell incubation time. In contrast to dextran microspheres, we did not observe PEGT/PBT microsphere degradation after 1 week of internalization by macrophages, confirming previous studies showing that dextran microsphere degradation proceeds faster than PEGT/PBT degradation. Raman microscopy further showed the conversion of macrophages to lipid-laden foam cells upon prolonged incubation with both types of microspheres, suggesting that a cellular inflammatory response is induced by these biomaterials in cell culture. Our results exemplify the power of Raman microscopy to characterize microsphere degradation in cells and offer exciting prospects for this technique as a noninvasive, label-free optical tool in biomaterials histology and tissue engineering. PMID:17722552

  17. MoS{sub 2}–GO nanocomposites synthesized via a hydrothermal hydrogel method for solar light photocatalytic degradation of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yong; Zhou, Yifeng, E-mail: yifengzhou@126.com; Nie, Wangyan; Chen, Pengpeng, E-mail: chenpp@ahu.edu.cn

    2015-12-01

    Graphical abstract: - Highlights: • The molybdenum disulfide–graphene oxide (MoS{sub 2}–GO) nanocomposite was synthesized via a one-step hydrothermal hydrogel method. • MoS{sub 2} and GO were composited fairly well in the obtained nanocomposites. • The electrons–hole pair recombination rate of MoS{sub 2} was greatly reduced via compositing with graphene. • The MoS{sub 2}–GO nanocomposite exhibited excellent photocatalytic performance for the degradation of methylene blue under solar light irradiation. - Abstract: In this work, molybdenum disulfide–graphene oxide (MoS{sub 2}–GO) composite hydrogel was prepared via a one-step hydrothermal method. The morphology and structure of the as-prepared hydrogels with different proportions of MoS{sub 2} and GO were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical impedance spectra and UV–vis absorption spectroscopy. The photocatalytic performance of MoS{sub 2}–GO nanocomposites was studied toward the degradation of methylene blue (MB). Results showed that the MoS{sub 2}–GO nanocomposites exhibited improved photocatalytic activities in the degradation of MB with a maximum degradation rate of 99% under solar lights irradiation within 60 min. The synthesized MoS{sub 2}–GO composite hydrogel possesses great potential toward the development of newly synthesizable catalysts in the field of organic degradation in water.

  18. Interplay between stiffness and degradation of architectured gelatin hydrogels leads to differential modulation of chondrogenesis in vitro and in vivo.

    Science.gov (United States)

    Sarem, Melika; Arya, Neha; Heizmann, Miriam; Neffe, Axel T; Barbero, Andrea; Gebauer, Tim P; Martin, Ivan; Lendlein, Andreas; Shastri, V Prasad

    2018-03-15

    The limited capacity of cartilage to heal large lesions through endogenous mechanisms has led to extensive effort to develop materials to facilitate chondrogenesis. Although physical-chemical properties of biomaterials have been shown to impact in vitro chondrogenesis, whether these findings are translatable in vivo is subject of debate. Herein, architectured 3D hydrogel scaffolds (ArcGel) (produced by crosslinking gelatin with ethyl lysine diisocyanate (LDI)) were used as a model system to investigate the interplay between scaffold mechanical properties and degradation on matrix deposition by human articular chondrocytes (HAC) from healthy donors in vitro and in vivo. Using ArcGel scaffolds of different tensile and shear modulus, and degradation behavior; in this study, we compared the fate of ex vivo engineered ArcGels-chondrocytes constructs, i.e. the traditional tissue engineering approach, with thede novoformation of cartilaginous tissue in HAC laden ArcGels in an ectopic nude mouse model. While the softer and fast degrading ArcGel (LNCO3) was more efficient at promoting chondrogenic differentiation in vitro, upon ectopic implantation, the stiffer and slow degrading ArcGel (LNCO8) was superior in maintaining chondrogenic phenotype in HAC and retention of cartilaginous matrix. Furthermore, surprisingly the de novo formation of cartilage tissue was promoted only in LNCO8. Since HAC cultured for only three days in the LNCO8 environment showed upregulation of hypoxia-associated genes, this suggests a potential role for hypoxia in the observed in vivo outcomes. In summary, this study sheds light on how immediate environment (in vivo versus in vitro) can significantly impact the outcomes of cell-laden biomaterials. In this study, 3D architectured hydrogels (ArcGels) with different mechanical and biodegradation properties were investigated for their potential to promote formation of cartilaginous matrix by human articular chondrocytes in vitro and in vivo. Two

  19. Reductively degradable poly(2-hydroxyethyl methacrylate) hydrogels with oriented porosity for tissue engineering applications

    Czech Academy of Sciences Publication Activity Database

    Macková, Hana; Plichta, Zdeněk; Hlídková, Helena; Sedláček, Ondřej; Konefal, Rafal; Sadakbayeva, Zhansaya; Dušková-Smrčková, Miroslava; Horák, Daniel; Kubinová, Šárka

    2017-01-01

    Roč. 9, č. 12 (2017), s. 10544-10553 ISSN 1944-8244 R&D Projects: GA ČR(CZ) GA14-14961S Institutional support: RVO:61389013 ; RVO:68378041 Keywords : poly(2-hydroxyethyl methacrylate) * 2-methacryloyloxyethyl phosphorylcholine * hydrogel Subject RIV: CD - Macromolecular Chemistry; JJ - Other Materials (UEM-P) OBOR OECD: Polymer science; Nano-materials (production and properties) (UEM-P) Impact factor: 7.504, year: 2016

  20. Digital Drug Dosing: Dosing in Drug Assays by Light-Defined Volumes of Hydrogels with Embedded Drug-Loaded Nanoparticles

    DEFF Research Database (Denmark)

    Faralli, Adele; Melander, Fredrik; Larsen, Esben Kjær Unmack

    2014-01-01

    Polyethylene glycol (PEG)-based hydrogels are widely used for biomedical applications, including matrices for controlled drug release. We present a method for defining drug dosing in screening assays by light-activated cross-linking of PEG-diacrylate hydrogels with embedded drug-loaded liposome...

  1. Transient Dynamic Mechanical Analysis of Resilin-based Elastomeric Hydrogels

    Science.gov (United States)

    Li, Linqing; Kiick, Kristi

    2014-04-01

    The outstanding high-frequency properties of emerging resilin-like polypeptides (RLPs) have motivated their development for vocal fold tissue regeneration and other applications. Recombinant RLP hydrogels show efficient gelation, tunable mechanical properties, and display excellent extensibility, but little has been reported about their transient mechanical properties. In this manuscript, we describe the transient mechanical behavior of new RLP hydrogels investigated via both sinusoidal oscillatory shear deformation and uniaxial tensile testing. Oscillatory stress relaxation and creep experiments confirm that RLP-based hydrogels display significantly reduced stress relaxation and improved strain recovery compared to PEG-based control hydrogels. Uniaxial tensile testing confirms the negligible hysteresis, reversible elasticity and superior resilience (up to 98%) of hydrated RLP hydrogels, with Young’s modulus values that compare favorably with those previously reported for resilin and that mimic the tensile properties of the vocal fold ligament at low strain (engineering applications, of a range of RLP hydrogels.

  2. A paradigm for peptide vaccine delivery using viral epitopes encapsulated in degradable polymer hydrogel capsules.

    Science.gov (United States)

    Chong, Siow-Feng; Sexton, Amy; De Rose, Robert; Kent, Stephen J; Zelikin, Alexander N; Caruso, Frank

    2009-10-01

    We report on the use of degradable polymer capsules as carriers for the delivery of oligopeptide antigens to professional antigen presenting cells (APCs). To achieve encapsulation, oligopeptide sequences were covalently linked to a negatively charged carrier polymer via biodegradable linkages and the resulting conjugate was then adsorbed onto amine-functionalized silica particles. These peptide-coated particles were then used as templates for the layer-by-layer (LbL) deposition of thiolated poly(methacrylic acid) (PMA(SH)) and poly(vinylpyrrolidone) (PVPON) multilayers. Removal of the silica core and disruption of the hydrogen bonding between PMA(SH) and PVPON by altering the solution pH yielded disulfide-stabilized PMA capsules that retain the encapsulated cargo in an oxidative environment. In the presence of a natural reducing agent, glutathione, cleavage of the disulfide bonds causes release of the peptide from the capsules. The developed strategy provides control over peptide loading into polymer capsules and yields colloidally stable micron- and submicron-sized carriers with uniform size and peptide loading. The conjugation and encapsulation procedures were proven to be non-degrading to the peptide vaccines. The peptide-loaded capsules were successfully used to deliver their cargo to APCs and activate CD8 T lymphocytes in a non-human primate model of SIV infection ex vivo. The reported approach represents a novel paradigm in the delivery of peptide vaccines and other therapeutic agents.

  3. The in vitro effects of macrophages on the osteogenic capabilities of MC3T3-E1 cells encapsulated in a biomimetic poly(ethylene glycol) hydrogel.

    Science.gov (United States)

    Saleh, Leila S; Carles-Carner, Maria; Bryant, Stephanie J

    2018-04-15

    Poly(ethylene glycol) PEG-based hydrogels are promising for cell encapsulation and tissue engineering, but are known to elicit a foreign body response (FBR) in vivo. The goal of this study was to investigate the impact of the FBR, and specifically the presence of inflammatory macrophages, on encapsulated cells and their ability to synthesize new extracellular matrix. This study employed an in vitro co-culture system with murine macrophages and MC3T3-E1 pre-osteoblasts encapsulated in a bone-mimetic hydrogel, which were cultured in transwell inserts, and exposed to an inflammatory stimulant, lipopolysaccharide (LPS). The co-culture was compared to mono-cultures of the cell-laden hydrogels alone and with LPS over 28 days. Two macrophage cell sources, RAW 264.7 and primary derived, were investigated. The presence of LPS-stimulated primary macrophages led to significant changes in the cell-laden hydrogel by a 5.3-fold increase in percent apoptotic osteoblasts at day 28, 4.2-fold decrease in alkaline phosphatase activity at day 10, and 7-fold decrease in collagen deposition. The presence of LPS-stimulated RAW macrophages led to significant changes in the cell-laden hydrogel by 5-fold decrease in alkaline phosphatase activity at day 10 and 4-fold decrease in collagen deposition. Mineralization, as measured by von Kossa stain or quantified by calcium content, was not sensitive to macrophages or LPS. Elevated interleukin-6 and tumor necrosis factor-α secretion were detected in mono-cultures with LPS and co-cultures. Overall, primary macrophages had a more severe inhibitory effect on osteoblast differentiation than the macrophage cell line, with greater apoptosis and collagen I reduction. In summary, this study highlights the detrimental effects of macrophages on encapsulated cells for bone tissue engineering. Poly(ethylene glycol) (PEG)-based hydrogels are promising for cell encapsulation and tissue engineering, but are known to elicit a foreign body response (FBR) in

  4. Osteochondral repair in the rabbit model utilizing bilayered, degradable oligo(poly(ethylene glycol) fumarate) hydrogel scaffolds.

    NARCIS (Netherlands)

    Holland, T.A.; Bodde, E.W.H.; Baggett, L.S.; Tabata, Y.; Mikos, A.G.; Jansen, J.A.

    2005-01-01

    In this study, hydrogel scaffolds, based on the polymer oligo(poly(ethylene glycol) fumarate) (OPF), were implanted into osteochondral defects in the rabbit model. Scaffolds consisted of two layers-a bottom, bone forming layer and a top, cartilage forming layer. Three scaffold formulations were

  5. Poly(ethylene glycol)-containing hydrogel surfaces for antifouling applications in marine and freshwater environments

    NARCIS (Netherlands)

    Ekblad, T.; Bergström, G.; Ederth, T.; Conlan, S.L.; Mutton, R.; Clare, A.S.; Wang, S.; Liu, Y.; Zhao, Q.; D'Souza, F.; Donnelly, G.T.; Willemsen, P.R.; Pettitt, M.E.; Callow, M.E.; Callow, J.A.; Liedberg, B.

    2008-01-01

    This work describes the fabrication, characterization, and biological evaluation of a thin protein-resistant poly(ethylene glycol) (PEG)-based hydrogel coating for antifouling applications. The coating was fabricated by free-radical polymerization on silanized glass and silicon and on

  6. Biodegradable and biocompatible poly(ethylene glycol)-based hydrogel films for the regeneration of corneal endothelium.

    Science.gov (United States)

    Ozcelik, Berkay; Brown, Karl D; Blencowe, Anton; Ladewig, Katharina; Stevens, Geoffrey W; Scheerlinck, Jean-Pierre Y; Abberton, Keren; Daniell, Mark; Qiao, Greg G

    2014-09-01

    Corneal endothelial cells (CECs) are responsible for maintaining the transparency of the human cornea. Loss of CECs results in blindness, requiring corneal transplantation. In this study, fabrication of biocompatible and biodegradable poly(ethylene glycol) (PEG)-based hydrogel films (PHFs) for the regeneration and transplantation of CECs is described. The 50-μm thin hydrogel films have similar or greater tensile strengths to human corneal tissue. Light transmission studies reveal that the films are >98% optically transparent, while in vitro degradation studies demonstrate their biodegradation characteristics. Cell culture studies demonstrate the regeneration of sheep corneal endothelium on the PHFs. Although sheep CECs do not regenerate in vivo, these cells proliferate on the films with natural morphology and become 100% confluent within 7 d. Implantation of the PHFs into live sheep corneas demonstrates the robustness of the films for surgical purposes. Regular slit lamp examinations and histology of the cornea after 28 d following surgery reveal minimal inflammatory responses and no toxicity, indicating that the films are benign. The results of this study suggest that PHFs are excellent candidates as platforms for the regeneration and transplantation of CECs as a result of their favorable biocompatibility, degradability, mechanical, and optical properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Sequentially-crosslinked bioactive hydrogels as nano-patterned substrates with customizable stiffness and degradation for corneal tissue engineering applications.

    Science.gov (United States)

    Rizwan, Muhammad; Peh, Gary S L; Ang, Heng-Pei; Lwin, Nyein Chan; Adnan, Khadijah; Mehta, Jodhbir S; Tan, Wui Siew; Yim, Evelyn K F

    2017-03-01

    Naturally-bioactive hydrogels like gelatin provide favorable properties for tissue-engineering but lack sufficient mechanical strength for use as implantable tissue engineering substrates. Complex fabrication or multi-component additives can improve material strength, but often compromises other properties. Studies have shown gelatin methacrylate (GelMA) as a bioactive hydrogel with diverse tissue growth applications. We hypothesize that, with suitable material modifications, GelMA could be employed for growth and implantation of tissue-engineered human corneal endothelial cell (HCEC) monolayer. Tissue-engineered HCEC monolayer could potentially be used to treat corneal blindness due to corneal endothelium dysfunction. Here, we exploited a sequential hybrid (physical followed by UV) crosslinking to create an improved material, named as GelMA+, with over 8-fold increase in mechanical strength as compared to regular GelMA. The presence of physical associations increased the subsequent UV-crosslinking efficiency resulting in robust materials able to withstand standard endothelium insertion surgical device loading. Favorable biodegradation kinetics were also measured in vitro and in vivo. We achieved hydrogels patterning with nano-scale resolution by use of oxygen impermeable stamps that overcome the limitations of PDMS based molding processes. Primary HCEC monolayers grown on GelMA+ carrier patterned with pillars of optimal dimension demonstrated improved zona-occludin-1 expression, higher cell density and cell size homogeneity, which are indications of functionally-superior transplantable monolayers. The hybrid crosslinking and fabrication approach offers potential utility for development of implantable tissue-engineered cell-carrier constructs with enhanced bio-functional properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. The Formation Mechanism of Hydrogels.

    Science.gov (United States)

    Lu, Liyan; Yuan, Shiliang; Wang, Jing; Shen, Yun; Deng, Shuwen; Xie, Luyang; Yang, Qixiang

    2017-06-12

    Hydrogels are degradable polymeric networks, in which cross-links play a vital role in structure formation and degradation. Cross-linking is a stabilization process in polymer chemistry that leads to the multi-dimensional extension of polymeric chains, resulting in network structures. By cross-linking, hydrogels are formed into stable structures that differ from their raw materials. Generally, hydrogels can be prepared from either synthetic or natural polymers. Based on the types of cross-link junctions, hydrogels can be categorized into two groups: the chemically cross-linked and the physically cross-linked. Chemically cross-linked gels have permanent junctions, in which covalent bonds are present between different polymer chains, thus leading to excellent mechanical strength. Although chemical cross-linking is a highly resourceful method for the formation of hydrogels, the cross-linkers used in hydrogel preparation should be extracted from the hydrogels before use, due to their reported toxicity, while, in physically cross-linked gels, dissolution is prevented by physical interactions, such as ionic interactions, hydrogen bonds or hydrophobic interactions. Physically cross-linked methods for the preparation of hydrogels are the alternate solution for cross-linker toxicity. Both methods will be discussed in this essay. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. Antifouling activities of β-cyclodextrin stabilized peg based silver nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Punitha, N., E-mail: punithasan@gmail.com [Department of Physics, St. Joseph’s College of Engineering, Chennai 600119 (India); Saravanan, P. [Department of Chemistry, St. Joseph’s College of Engineering, Chennai 600119 (India); Mohan, R. [Department of Physics, Surya College of Engineering and Technology, Villupuram (India); Ramesh, P.S. [Department of Physics (DDE), Annamalai University, Annamalai Nagar 608002 (India)

    2017-01-15

    Highlights: • Simple, novel and cost effective. • Functionalized Ag nanocomposites exhibit enhanced biological activity. • The SNCs were crystalline nature and shows good stability. - Abstract: Self-polishing polymer composites which release metal biocide in a controlled rate have been widely used in the design of antimicrobial agents and antifouling coatings. The present work focuses on the environmental friendly green synthesis of PEG based SNCs and their application to biocidal activity including marine biofouling. Biocompatible polymer β-CD and adhesive resistance polymer PEG were used to functionalize the SNPs and the as synthesized SNCs exhibit excellent micro fouling activities. The structural and optical properties were confirmed by XRD and UV–visible techniques respectively. The particle surface and cross sectional characteristics were examined by SEM-EDS, HR-TEM, AFM and FTIR. The surface potential was evaluated using ZP analysis and assessment of antibiofouling property was investigated using static immersion method.

  10. Antifouling activities of β-cyclodextrin stabilized peg based silver nanocomposites

    Science.gov (United States)

    Punitha, N.; Saravanan, P.; Mohan, R.; Ramesh, P. S.

    2017-01-01

    Self-polishing polymer composites which release metal biocide in a controlled rate have been widely used in the design of antimicrobial agents and antifouling coatings. The present work focuses on the environmental friendly green synthesis of PEG based SNCs and their application to biocidal activity including marine biofouling. Biocompatible polymer β-CD and adhesive resistance polymer PEG were used to functionalize the SNPs and the as synthesized SNCs exhibit excellent micro fouling activities. The structural and optical properties were confirmed by XRD and UV-visible techniques respectively. The particle surface and cross sectional characteristics were examined by SEM-EDS, HR-TEM, AFM and FTIR. The surface potential was evaluated using ZP analysis and assessment of antibiofouling property was investigated using static immersion method.

  11. Antifouling activities of β-cyclodextrin stabilized peg based silver nanocomposites

    International Nuclear Information System (INIS)

    Punitha, N.; Saravanan, P.; Mohan, R.; Ramesh, P.S.

    2017-01-01

    Highlights: • Simple, novel and cost effective. • Functionalized Ag nanocomposites exhibit enhanced biological activity. • The SNCs were crystalline nature and shows good stability. - Abstract: Self-polishing polymer composites which release metal biocide in a controlled rate have been widely used in the design of antimicrobial agents and antifouling coatings. The present work focuses on the environmental friendly green synthesis of PEG based SNCs and their application to biocidal activity including marine biofouling. Biocompatible polymer β-CD and adhesive resistance polymer PEG were used to functionalize the SNPs and the as synthesized SNCs exhibit excellent micro fouling activities. The structural and optical properties were confirmed by XRD and UV–visible techniques respectively. The particle surface and cross sectional characteristics were examined by SEM-EDS, HR-TEM, AFM and FTIR. The surface potential was evaluated using ZP analysis and assessment of antibiofouling property was investigated using static immersion method.

  12. Optimization of PEG-based extraction of polysaccharides from Dendrobium nobile Lindl. and bioactivity study.

    Science.gov (United States)

    Zhang, Yi; Wang, Hongxin; Wang, Peng; Ma, ChaoYang; He, GuoHua; Rahman, Md Ramim Tanver

    2016-11-01

    Polyethylene glycol (PEG) as a green solvent was employed to extract polysaccharide. The optimal conditions for PEG-based ultrasonic extraction of Dendrobium nobile Lindl. polysaccharide (JCP) were determined by response surface methodology. Under the optimal conditions: extraction temperature of 58.5°C; ultrasound power of 193W, and the concentration of polyethylene glycol-200 (PEG-200) solution of 45%, the highest JCP yield was obtained as 15.23±0.57%, which was close to the predicted yield, 15.57%. UV and FT-IR analysis revealed the general characteristic absorption peaks of both JCP with water extraction (JCP w ) and PEG-200 solvent extraction (JCP p ). Thermal analysis of both JCPs was performed with Thermal Gravimetric Analyzer (TGA) and Differential Scanning Calorimeter (DSC). Antioxidant activities of two polysaccharides were also compared and no significant difference in vitro was obtained. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Stereocomplexed 8-armed poly(ethylene glycol)-poly(lactide) star block copolymer hydrogels: Gelation mechanism, mechanical properties and degradation behavior

    NARCIS (Netherlands)

    Buwalda, S.J.; Calucci, L.; Forte, C.; Dijkstra, Pieter J.; Feijen, Jan

    2012-01-01

    Mixing aqueous poly(ethylene glycol)-poly(d-lactide) and poly(ethylene glycol)-poly(l-lactide) star block copolymer solutions resulted in the formation of stereocomplexed hydrogels within 1 min. A study towards the mechanism of the temperature dependent formation of stereocomplexes in the hydrogels

  14. Synthesis and Characterization of Phosphated Konjac Glucomannan Hydrogels

    Institute of Scientific and Technical Information of China (English)

    Li Gui CHEN; Zhi Lan LIU; Ying Jun CHEN; Ren Xi ZHUO

    2005-01-01

    Konjac glucomannan (KGM) was crosslinked with sodium tripolyphosphate (STPP) to synthesize hydrogels. The crosslinking reaction was confirmed by FT-IR. The results of degradation test show that the hydrogels retain the enzymatic degradation character of KGM and can be degraded for 74.45% in 5 days by cellulase E0240.

  15. Effect of MWCNT Filler on Properties and Flux of Chitosan/ PEG based Nanocomposites Membranes

    Directory of Open Access Journals (Sweden)

    Khoerunnisa Fitri

    2018-01-01

    Full Text Available Biopolymer are expected to be environmentally compatible and to have great potential application as membranes material. The chitosan-poly (ethylene glycol/PEG based composite membranes was successfully synthesized via inversed phase method. The effect of multiwalled carbon nanotubes (MWCNT as nanofiller on properties and performances of composite membranes were intensively evaluated. The membrane was prepared by mixing of chitosan and PEG solutions at the same composition ratio while MWCNT amount in the mixture was varied. The synthesized membrane was characterized by means of FTIR spectroscopy, scanning electron microscopy (SEM, contact angle, and tensile strength measurement. The performance of composite membrane on filtration was evaluated in term of flux (permeability and rejection (rejection tests. The results showed that the optimum volume ratio of composite membrane solution was found at 30:10:7.5 for chitosan/ PEG/ MWCNT, respectively, as indicated by the largest flux. Insertion of MWCNT nanofiller notably enhanced hydrophilicity, porosity, and mechanical properties of composites membranes that are confirmed by contact angle, SEM images and elongation forces value, respectively. The MWCNT nanofiller remarkably increased both of flux and rejection of composite membranes up to 60 Lm2h-1 and 96%, respectively. The remarkable enhancement of composite membrane performance is attributed to the effective interaction of MWCNT with polymeric matrix.

  16. Fibrin-genipin adhesive hydrogel for annulus fibrosus repair: performance evaluation with large animal organ culture, in situ biomechanics, and in vivo degradation tests

    Directory of Open Access Journals (Sweden)

    M Likhitpanichkul

    2014-07-01

    Full Text Available Annulus fibrosus (AF defects from annular tears, herniation, and discectomy procedures are associated with painful conditions and accelerated intervertebral disc (IVD degeneration. Currently, no effective treatments exist to repair AF damage, restore IVD biomechanics and promote tissue regeneration. An injectable fibrin-genipin adhesive hydrogel (Fib-Gen was evaluated for its performance repairing large AF defects in a bovine caudal IVD model using ex vivo organ culture and biomechanical testing of motion segments, and for its in vivo longevity and biocompatibility in a rat model by subcutaneous implantation. Fib-Gen sealed AF defects, prevented IVD height loss, and remained well-integrated with native AF tissue following approximately 14,000 cycles of compression in 6-day organ culture experiments. Fib-Gen repair also retained high viability of native AF cells near the repair site, reduced nitric oxide released to the media, and showed evidence of AF cell migration into the gel. Biomechanically, Fib-Gen fully restored compressive stiffness to intact levels validating organ culture findings. However, only partial restoration of tensile and torsional stiffness was obtained, suggesting opportunities to enhance this formulation. Subcutaneous implantation results, when compared with the literature, suggested Fib-Gen exhibited similar biocompatibility behaviour to fibrin alone but degraded much more slowly. We conclude that injectable Fib-Gen successfully sealed large AF defects, promoted functional restoration with improved motion segment biomechanics, and served as a biocompatible adhesive biomaterial that had greatly enhanced in vivo longevity compared to fibrin. Fib-Gen offers promise for AF repairs that may prevent painful conditions and accelerated degeneration of the IVD, and warrants further material development and evaluation.

  17. Studies on radiation synthesis of polyethyleneimine/acrylamide hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Sanju [ISOMED, Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India); Varshney, Lalit [ISOMED, Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)]. E-mail: lalitv@magnum.barc.ernet.in; Tirumalesh, K. [Isotope Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)

    2006-07-15

    Polyethyleneimine(PEI)/acrylamide(AAM) hydrogels were synthesized by {gamma}-radiation-induced polymerization/crosslinking of aqueous mixtures containing different ratios of PEI and AAM. The gel percentage and equilibrium degree of swelling (EDS) of the synthesized hydrogels were investigated. The compositions of the hydrogels produced were found to be different from the feed composition. Ion-chromatography technique was used to determine the amount of Pb (II) and Cd (II) absorbed by the hydrogel. The maximum binding capacity of the PEI/AAM hydrogels, for Pb and Cd was found to be 19 and 12.6 mg/g, respectively (at 100 ppm). PEI/AAM hydrogels had better metal uptake efficiency than the pure AAM hydrogel at concentrations less than 50 ppm. Pure PEI was observed to be highly degrading type polymer on exposure to gamma radiation. TGA and FT-IR techniques were used to characterize the prepared hydrogels.

  18. Fluxgate magnetorelaxometry of superparamagnetic nanoparticles for hydrogel characterization

    International Nuclear Information System (INIS)

    Heim, Erik; Harling, Steffen; Poehlig, Kai; Ludwig, Frank; Menzel, Henning; Schilling, Meinhard

    2007-01-01

    A new characterization method for hydrogels based on the relaxation behavior of superparamagnetic nanoparticles (MNPs) is proposed. MNPs are incorporated in the hydrogel to examine its network properties. By analyzing their relaxation behavior, incorporated and mobile nanoparticles can be studied. In the case of mobile nanoparticles, the microviscosity of the hydrogel can be determined. Thus, this method allows the studying of gelation as well as the degradation process of hydrogels. Furthermore, the hydrogel can have any shape (e.g. microspheres or larger blocks) and no sample preparation is needed, avoiding artefacts

  19. Keratocyte behavior in three-dimensional photopolymerizable poly(ethylene glycol) hydrogels

    Science.gov (United States)

    Thibault, Richard; Ambrose, Winnette McIntosh; Schein, Oliver D.; Chakravarti, Shukti; Elisseeff, Jennifer

    2015-01-01

    The goal of this study was to evaluate three-dimensional (3-D) poly(ethylene glycol) (PEG) hydrogels as a culture system for studying corneal keratocytes. Bovine keratocytes were subcultured in DMEM/F-12 containing 10% fetal bovine serum (FBS) through passage 5. Primary keratocytes (P0) and corneal fibroblasts from passages 1 (P1) and 3 (P3) were photoencapsulated at various cell concentrations in PEG hydrogels via brief exposure to light. Additional hydrogels contained adhesive YRGDS and nonadhesive YRDGS peptides. Hydrogel constructs were cultured in DMEM/F-12 with 10% FBS for 2 and 4 weeks. Cell viability was assessed by DNA quantification and vital staining. Biglycan, type I collagen, type III collagen, keratocan and lumican expression were determined by reverse transcriptase–polymerase chain reaction. Deposition of type I collagen, type III collagen and keratan sulfate (KS)-containing matrix components was visualized using confocal microscopy. Keratocytes in a monolayer lost their stellate morphology and keratocan expression, displayed elongated cell bodies, and up-regulated biglycan, type I collagen and type III collagen characteristic of corneal fibroblasts. Encapsulated keratocytes remained viable for 4 weeks with spherical morphologies. Hydrogels supported production of KS, type I collagen and type III collagen matrix components. PEG-based hydrogels can support keratocyte viability and matrix production. 3-D hydrogel culture can stabilize but not restore the keratocyte phenotype. This novel application of PEG hydrogels has potential use in the study of corneal keratocytes in a 3-D environment. PMID:18567550

  20. Enzymatically crosslinked silk-hyaluronic acid hydrogels.

    Science.gov (United States)

    Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

    2017-07-01

    In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Hydrogel based occlusion systems

    NARCIS (Netherlands)

    Stam, F.A.; Jackson, N.; Dubruel, P.; Adesanya, K.; Embrechts, A.; Mendes, E.; Neves, H.P.; Herijgers, P.; Verbrugghe, Y.; Shacham, Y.; Engel, L.; Krylov, V.

    2013-01-01

    A hydrogel based occlusion system, a method for occluding vessels, appendages or aneurysms, and a method for hydrogel synthesis are disclosed. The hydrogel based occlusion system includes a hydrogel having a shrunken and a swollen state and a delivery tool configured to deliver the hydrogel to a

  2. In situ forming poly(ethylene glycol)- Poly(L -lactide) hydrogels via michael addition: Mechanical properties, degradation, and protein release

    NARCIS (Netherlands)

    Buwalda, S.J.; Dijkstra, Pieter J.; Feijen, Jan

    2012-01-01

    Chemically crosslinked hydrogels are prepared at remarkably low macromonomer concentrations from 8-arm poly(ethylene glycol)-poly(L-lactide) star block copolymers bearing acrylate end groups (PEG-(PLLAn)8-AC, n = 4 or 12) and multifunctional PEG thiols (PEG-(SH)n, n = 2, 4, or 8) through a

  3. Alginate/PEG based microcarriers with cleavable crosslinkage for expansion and non-invasive harvest of human umbilical cord blood mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chunge [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, No. 92, Weijin Road, Tianjin 300072 (China); Qian, Yufeng [Department of Chemistry and Biochemistry, University of Texas at Austin, 2500 Speedway, Austin, TX 78712 (United States); Zhao, Shuang [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, No. 92, Weijin Road, Tianjin 300072 (China); Yin, Yuji, E-mail: yinyuji@tju.edu.cn [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, No. 92, Weijin Road, Tianjin 300072 (China); Li, Junjie, E-mail: li41308@tju.edu.cn [Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, No. 92, Weijin Road, Tianjin 300072 (China); Department of Advanced Interdisciplinary Studies, Institute of Basic Medical Sciences and Tissue Engineering Research Center, Academy of Military Medical Sciences, No. 27, Taiping Road, Beijing 100850 (China)

    2016-07-01

    Porous microcarriers are increasingly used to expand and harvest stem cells. Generally, the cells are harvested via proteolytic enzyme treatment, which always leads to damages to stem cells. To address this disadvantage, a series of alginate/PEG (AL/PEG) semi-interpenetrating network microcarriers are prepared in this study. In this AL/PEG system, the chemically cross-linked alginate networks are formed via the reaction between carboxylic acid group of alginate and di-terminated amine groups of cystamine. PEG is introduced to modulate the degradation of microcarriers, which does not participate in this cross-linked reaction, while it interpenetrates in alginate network via physical interactions. In addition, chitosan are coated on the surface of AL/PEG to improve the mechanical strength via the electrostatic interactions. Biocompatible fibronectin are also coated on these microcarriers to modulate the biological behaviors of cells seeded in microcarriers. Results suggest that the size of AL/PEG microcarriers can be modulated via adjusting the contents and molecular weight of PEG. Moreover, the microcarriers are designed to be degraded with cleavage of disulfide crosslinkage. By changing the type and concentration of reductant, the ratio of AL to PEG, and the magnitude of chitosan coating, the degradation ability of AL/PEG microcarriers can be well controlled. In addition, AL/PEG microcarriers can support the attachment and proliferation of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs). More importantly, the expanded hUCB-MSCs can be detached from microcarriers after addition of reductant, which indeed reduce the cell damage caused by proteolytic enzyme treatment. Therefore, it is convinced that AL/PEG based microcarriers will be a promising candidate for large-scale expansion of hUCB-MSCs. - Graphical abstract: Alginate/PEG IPN microcarriers can support the attachment and expansion of hUCB-MSCs. More importantly, the expanded cells can be harvested

  4. Alginate/PEG based microcarriers with cleavable crosslinkage for expansion and non-invasive harvest of human umbilical cord blood mesenchymal stem cells

    International Nuclear Information System (INIS)

    Li, Chunge; Qian, Yufeng; Zhao, Shuang; Yin, Yuji; Li, Junjie

    2016-01-01

    Porous microcarriers are increasingly used to expand and harvest stem cells. Generally, the cells are harvested via proteolytic enzyme treatment, which always leads to damages to stem cells. To address this disadvantage, a series of alginate/PEG (AL/PEG) semi-interpenetrating network microcarriers are prepared in this study. In this AL/PEG system, the chemically cross-linked alginate networks are formed via the reaction between carboxylic acid group of alginate and di-terminated amine groups of cystamine. PEG is introduced to modulate the degradation of microcarriers, which does not participate in this cross-linked reaction, while it interpenetrates in alginate network via physical interactions. In addition, chitosan are coated on the surface of AL/PEG to improve the mechanical strength via the electrostatic interactions. Biocompatible fibronectin are also coated on these microcarriers to modulate the biological behaviors of cells seeded in microcarriers. Results suggest that the size of AL/PEG microcarriers can be modulated via adjusting the contents and molecular weight of PEG. Moreover, the microcarriers are designed to be degraded with cleavage of disulfide crosslinkage. By changing the type and concentration of reductant, the ratio of AL to PEG, and the magnitude of chitosan coating, the degradation ability of AL/PEG microcarriers can be well controlled. In addition, AL/PEG microcarriers can support the attachment and proliferation of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs). More importantly, the expanded hUCB-MSCs can be detached from microcarriers after addition of reductant, which indeed reduce the cell damage caused by proteolytic enzyme treatment. Therefore, it is convinced that AL/PEG based microcarriers will be a promising candidate for large-scale expansion of hUCB-MSCs. - Graphical abstract: Alginate/PEG IPN microcarriers can support the attachment and expansion of hUCB-MSCs. More importantly, the expanded cells can be harvested

  5. Smart hydrogel functional materials

    CERN Document Server

    Chu, Liang-Yin; Ju, Xiao-Jie

    2014-01-01

    This book systematically introduces smart hydrogel functional materials with the configurations ranging from hydrogels to microgels. It serves as an excellent reference for designing and fabricating artificial smart hydrogel functional materials.

  6. Biomolecule-Responsive Hydrogels in Medicine.

    Science.gov (United States)

    Sharifzadeh, Ghorbanali; Hosseinkhani, Hossein

    2017-12-01

    Recent advances and applications of biomolecule-responsive hydrogels, namely, glucose-responsive hydrogels, protein-responsive hydrogels, and nucleic-acid-responsive hydrogels are highlighted. However, achieving the ultimate purpose of using biomolecule-responsive hydrogels in preclinical and clinical areas is still at the very early stage and calls for more novel designing concepts and advance ideas. On the way toward the real/clinical application of biomolecule-responsive hydrogels, plenty of factors should be extensively studied and examined under both in vitro and in vivo conditions. For example, biocompatibility, biointegration, and toxicity of biomolecule-responsive hydrogels should be carefully evaluated. From the living body's point of view, biocompatibility is seriously depended on the interactions at the tissue/polymer interface. These interactions are influenced by physical nature, chemical structure, surface properties, and degradation of the materials. In addition, the developments of advanced hydrogels with tunable biological and mechanical properties which cause no/low side effects are of great importance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Long-Term Stability of PEG-Based Antifouling Surfaces in a Marine Environment

    DEFF Research Database (Denmark)

    Noguer, Albert Camós; Kiil, Søren; Hvilsted, Søren

    are disclosed. The results show how the degradation of different polyethers can be followed, both in laboratory accelerated conditions and real life exposure by size exclusion chromatography (SEC) and nuclear magnetic resonance spectroscopy (NMR). Preliminary results indicate the influence of the chemical...

  8. Adhesive PEG-based binder for aqueous fabrication of thick Li4Ti5O12 electrode

    International Nuclear Information System (INIS)

    Tran, Binh; Oladeji, Isaiah O.; Wang, Zedong; Calderon, Jean; Chai, Guangyu; Atherton, David; Zhai, Lei

    2013-01-01

    We report the first fully compressed Li 4 Ti 5 O 12 electrode designed by an aqueous process. An adhesive, elastomeric, and lithium ion conductive PEG-based copolymer is used as a binder for the aqueous fabrication thick, flexible, and densely packed Li 4 Ti 5 O 12 (LTO) electrodes. Self-adherent cathode films exceeding 200 μm in thickness and withholding high active mass loadings of 28 mg/cm 2 deliver 4.2 mAh/cm 2 at C/2 rate. Structurally defect-free electrodes are fabricated by casting aqueous cathode slurries onto nickel foam, dried, and hard-calendared at 10 tons/cm 2 . As a multifunctional material, the binder is synthesized by the copolymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA), methyl methacrylate (MMA), and isobutyl vinyl ether (IBVE) in optimal proportions. Furthermore, coordinating the binder with lithium salt is necessary for the electrode to function

  9. Thermal Stabilization of Biologics with Photoresponsive Hydrogels.

    Science.gov (United States)

    Sridhar, Balaji V; Janczy, John R; Hatlevik, Øyvind; Wolfson, Gabriel; Anseth, Kristi S; Tibbitt, Mark W

    2018-03-12

    Modern medicine, biological research, and clinical diagnostics depend on the reliable supply and storage of complex biomolecules. However, biomolecules are inherently susceptible to thermal stress and the global distribution of value-added biologics, including vaccines, biotherapeutics, and Research Use Only (RUO) proteins, requires an integrated cold chain from point of manufacture to point of use. To mitigate reliance on the cold chain, formulations have been engineered to protect biologics from thermal stress, including materials-based strategies that impart thermal stability via direct encapsulation of the molecule. While direct encapsulation has demonstrated pronounced stabilization of proteins and complex biological fluids, no solution offers thermal stability while enabling facile and on-demand release from the encapsulating material, a critical feature for broad use. Here we show that direct encapsulation within synthetic, photoresponsive hydrogels protected biologics from thermal stress and afforded user-defined release at the point of use. The poly(ethylene glycol) (PEG)-based hydrogel was formed via a bioorthogonal, click reaction in the presence of biologics without impact on biologic activity. Cleavage of the installed photolabile moiety enabled subsequent dissolution of the network with light and release of the encapsulated biologic. Hydrogel encapsulation improved stability for encapsulated enzymes commonly used in molecular biology (β-galactosidase, alkaline phosphatase, and T4 DNA ligase) following thermal stress. β-galactosidase and alkaline phosphatase were stabilized for 4 weeks at temperatures up to 60 °C, and for 60 min at 85 °C for alkaline phosphatase. T4 DNA ligase, which loses activity rapidly at moderately elevated temperatures, was protected during thermal stress of 40 °C for 24 h and 60 °C for 30 min. These data demonstrate a general method to employ reversible polymer networks as robust excipients for thermal stability of complex

  10. Mechanical properties, structure, bioadhesion, and biocompatibility of pectin hydrogels.

    Science.gov (United States)

    Markov, Pavel A; Krachkovsky, Nikita S; Durnev, Eugene A; Martinson, Ekaterina A; Litvinets, Sergey G; Popov, Sergey V

    2017-09-01

    The surface structure, biocompatibility, textural, and adhesive properties of calcium hydrogels derived from 1, 2, and 4% solutions of apple pectin were examined in this study. An increase in the pectin concentration in hydrogels was shown to improve their stability toward elastic and plastic deformation. The elasticity of pectin hydrogels, measured as Young's modulus, ranged from 6 to 100 kPa. The mechanical properties of the pectin hydrogels were shown to correspond to those of soft tissues. The characterization of surface roughness in terms of the roughness profile (Ra) and the root-mean-square deviation of the roughness profile (Rq) indicated an increased roughness profile for hydrogels depending on their pectin concentration. The adhesion of AU2% and AU4% hydrogels to the serosa abdominal wall, liver, and colon was higher than that of the AU1% hydrogel. The adhesion of macrophages and the non-specific adsorption of blood plasma proteins were found to increase as the pectin concentration in the hydrogels increased. The rate of degradation of all hydrogels was higher in phosphate buffered saline (PBS) than that in DMEM and a fibroblast cell monolayer. The pectin hydrogel was also found to have a low cytotoxicity. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2572-2581, 2017. © 2017 Wiley Periodicals, Inc.

  11. Photodegradable, Photoadaptable Hydrogels via Radical-Mediated Disulfide Fragmentation Reaction.

    Science.gov (United States)

    Fairbanks, Benjamin D; Singh, Samir P; Bowman, Christopher N; Anseth, Kristi S

    2011-04-26

    Various techniques have been adopted to impart a biological responsiveness to synthetic hydrogels for the delivery of therapeutic agents as well as the study and manipulation of biological processes and tissue development. Such techniques and materials include polyelectrolyte gels that swell and deswell with changes in pH, thermosensitive gels that contract at physiological temperatures, and peptide cross-linked hydrogels that degrade upon peptidolysis by cell-secreted enzymes. Herein we report a unique approach to photochemically deform and degrade disulfide cross-linked hydrogels, mitigating the challenges of light attenuation and low quantum yield, permitting the degradation of hydrogels up to 2 mm thick within 120 s at low light intensities (10 mW/cm(2) at 365 nm). Hydrogels were formed by the oxidation of thiol-functionalized 4-armed poly(ethylene glycol) macromolecules. These disulfide cross-linked hydrogels were then swollen in a lithium acylphosphinate photoinitiator solution. Upon exposure to light, photogenerated radicals initiate multiple fragmentation and disulfide exchange reactions, permitting and promoting photodeformation, photowelding, and photodegradation. This novel, but simple, approach to generate photoadaptable hydrogels portends the study of cellular response to mechanically and topographically dynamic substrates as well as novel encapsulations by the welding of solid substrates. The principles and techniques described herein hold implications for more than hydrogel materials but also for photoadaptable polymers more generally.

  12. Development of a P((MAA-co-NVP)-g-EG) Hydrogel Platform for Oral Protein Delivery: Effects of Hydrogel Composition on Environmental Response and Protein Partitioning.

    Science.gov (United States)

    Steichen, Stephanie; O'Connor, Colleen; Peppas, Nicholas A

    2017-01-01

    Hydrogels based upon terpolymers of methacrylic acid, N-vinyl pyrrolidone, and poly(ethylene glycol) are developed and characterized for their ability to respond to changes in environmental pH and to partition protein therapeutics of varying molecular weights and isoelectric points. P((MAA-co-NVP)-g-EG) hydrogels are synthesized with PEG-based cross-linking agents of varying length and incorporation densities. The composition is confirmed using FT-IR spectroscopy and shows peak shifts indicating hydrogen bonding. Scanning electron microscopy reveals microparticles with an irregular, planar morphology. The pH-responsive behavior of the hydrogels is confirmed under equilibrium and dynamic conditions, with the hydrogel collapsed at acidic pH and swollen at neutral pH. The ability of the hydrogels to partition model protein therapeutics at varying pH and ionic strength is evaluated using three model proteins: insulin, porcine growth hormone, and ovalbumin. Finally, the microparticles are evaluated for adverse interactions with two model intestinal cell lines and show minimal cytotoxicity at concentrations below 5 mg mL -1 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Enhancement of Curcumin Bioavailability Using Nanocellulose Reinforced Chitosan Hydrogel

    Directory of Open Access Journals (Sweden)

    Thennakoon M. Sampath Udeni Gunathilake

    2017-02-01

    Full Text Available A unique biodegradable, superporous, swellable and pH sensitive nanocellulose reinforced chitosan hydrogel with dynamic mechanical properties was prepared for oral administration of curcumin. Curcumin, a less water-soluble drug was used due to the fact that the fast swellable, superporous hydrogel could release a water-insoluble drug to a great extent. CO2 gas foaming was used to fabricate hydrogel as it eradicates using organic solvents. Field emission scanning electron microscope images revealed that the pore size significantly increased with the formation of widely interconnected porous structure in gas foamed hydrogels. The maximum compression of pure chitosan hydrogel was 25.9 ± 1 kPa and it increased to 38.4 ± 1 kPa with the introduction of 0.5% cellulose nanocrystals. In vitro degradation of hydrogels was found dependent on the swelling ratio and the amount of CNC of the hydrogel. All the hydrogels showed maximum swelling ratios greater than 300%. The 0.5% CNC-chitosan hydrogel showed the highest swelling ratio of 438% ± 11%. FTIR spectrum indicated that there is no interaction between drug and ingredients present in hydrogels. The drug release occurred in non-Fickian (anomalous manner in simulated gastric medium. The drug release profiles of hydrogels are consistent with the data obtained from the swelling studies. After gas foaming of the hydrogel, the drug loading efficiency increased from 41% ± 2.4% to 50% ± 2.0% and release increased from 0.74 to 1.06 mg/L. The drug release data showed good fitting to Ritger-Peppas model. Moreover, the results revealed that the drug maintained its chemical activity after in vitro release. According to the results of this study, CNC reinforced chitosan hydrogel can be suggested to improve the bioavailability of curcumin for the absorption from stomach and upper intestinal tract.

  14. Synthesis and Properties of IPN Hydrogels Based on Konjac Glucomannan and Poly(acrylic acid)

    Institute of Scientific and Technical Information of China (English)

    Bing LIU; Zhi Lan LIU; Ren Xi ZHUO

    2006-01-01

    Novel interpenetrating polymer network (IPN) hydrogels based on konjac glucomannan (KGM) and poly(acrylic acid) (PAA) were prepared by polymerization and cross-linking of acrylic acid (AA) in the pre-fabricated KGM gel. The IPN gel was analyzed by FT-IR. The studies on the equilibrium swelling ratio of IPN hydrogels revealed their sensitive response to environmental pH value. The results of in vitro degradation showed that the IPN hydrogels retain the enzymatic degradation character of KGM.

  15. Improved stability and enhanced efficiency to degrade chlorimuron-ethyl by the entrapment of esterase SulE in cross-linked poly (γ-glutamic acid)/gelatin hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liqiang [State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang (China); University of Chinese Academy of Sciences, Beijing (China); Li, Xinyu; Li, Xu; Su, Zhencheng; Zhang, Chenggang; Xu, MingKai [State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang (China); Zhang, Huiwen, E-mail: hwzhang@iae.ac.cn [State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang (China)

    2015-04-28

    Highlights: • Esterase SulE was entrapped in a three-dimensional network of CPE. • CPE-SulE obviously improved thermostability, pH stability and reusability. • CPE-SulE displayed obviously enhanced efficiency in degrading chlorimuron-ethyl. • The three-dimensional network and kinetic parameters of CPE-SulE were analysed. • CPE-SulE possesses the great potential to remediate chlorimuron-ethyl contaminated in situ. - Abstract: Free enzymes often undergo some problems such as easy deactivation, low stability, and less recycling in biodegradation processes, especially in soil condition. A novel esterase SulE, which is responsible for primary degradation of a wide range of sulfonylurea herbicides by methyl or ethyl ester de-esterification, was expressed by strain Hansschlegelia sp. CHL1 and entrapped for the first time in an environment-friendly, biocompatible and biodegradable cross-linked poly (γ-glutamic acid)/gelatin hydrogel (CPE). The activity and stability of CPE-SulE were compared with free SulE under varying pH and temperature condition by measuring chlorimuron-ethyl residue. Meanwhile, the three-dimensional network of CPE-SulE was verified by scanning electron microscopy (SEM). The results showed that CPE-SulE obviously improved thermostability, pH stability and reusability compared with free SulE. Furthermore, CPE-SulE enhanced degrading efficiency of chlorimuron-ethyl in both soil and water system, especially in acid environment. The characteristics of CPE-SulE suggested the great potential to remediate chlorimuron-ethyl contaminated soils in situ.

  16. Improved stability and enhanced efficiency to degrade chlorimuron-ethyl by the entrapment of esterase SulE in cross-linked poly (γ-glutamic acid)/gelatin hydrogel

    International Nuclear Information System (INIS)

    Yang, Liqiang; Li, Xinyu; Li, Xu; Su, Zhencheng; Zhang, Chenggang; Xu, MingKai; Zhang, Huiwen

    2015-01-01

    Highlights: • Esterase SulE was entrapped in a three-dimensional network of CPE. • CPE-SulE obviously improved thermostability, pH stability and reusability. • CPE-SulE displayed obviously enhanced efficiency in degrading chlorimuron-ethyl. • The three-dimensional network and kinetic parameters of CPE-SulE were analysed. • CPE-SulE possesses the great potential to remediate chlorimuron-ethyl contaminated in situ. - Abstract: Free enzymes often undergo some problems such as easy deactivation, low stability, and less recycling in biodegradation processes, especially in soil condition. A novel esterase SulE, which is responsible for primary degradation of a wide range of sulfonylurea herbicides by methyl or ethyl ester de-esterification, was expressed by strain Hansschlegelia sp. CHL1 and entrapped for the first time in an environment-friendly, biocompatible and biodegradable cross-linked poly (γ-glutamic acid)/gelatin hydrogel (CPE). The activity and stability of CPE-SulE were compared with free SulE under varying pH and temperature condition by measuring chlorimuron-ethyl residue. Meanwhile, the three-dimensional network of CPE-SulE was verified by scanning electron microscopy (SEM). The results showed that CPE-SulE obviously improved thermostability, pH stability and reusability compared with free SulE. Furthermore, CPE-SulE enhanced degrading efficiency of chlorimuron-ethyl in both soil and water system, especially in acid environment. The characteristics of CPE-SulE suggested the great potential to remediate chlorimuron-ethyl contaminated soils in situ

  17. Bioprinting Cellularized Constructs Using a Tissue-specific Hydrogel Bioink

    Science.gov (United States)

    Skardal, Aleksander; Devarasetty, Mahesh; Kang, Hyun-Wook; Seol, Young-Joon; Forsythe, Steven D.; Bishop, Colin; Shupe, Thomas; Soker, Shay; Atala, Anthony

    2016-01-01

    Bioprinting has emerged as a versatile biofabrication approach for creating tissue engineered organ constructs. These constructs have potential use as organ replacements for implantation in patients, and also, when created on a smaller size scale as model "organoids" that can be used in in vitro systems for drug and toxicology screening. Despite development of a wide variety of bioprinting devices, application of bioprinting technology can be limited by the availability of materials that both expedite bioprinting procedures and support cell viability and function by providing tissue-specific cues. Here we describe a versatile hyaluronic acid (HA) and gelatin-based hydrogel system comprised of a multi-crosslinker, 2-stage crosslinking protocol, which can provide tissue specific biochemical signals and mimic the mechanical properties of in vivo tissues. Biochemical factors are provided by incorporating tissue-derived extracellular matrix materials, which include potent growth factors. Tissue mechanical properties are controlled combinations of PEG-based crosslinkers with varying molecular weights, geometries (linear or multi-arm), and functional groups to yield extrudable bioinks and final construct shear stiffness values over a wide range (100 Pa to 20 kPa). Using these parameters, hydrogel bioinks were used to bioprint primary liver spheroids in a liver-specific bioink to create in vitro liver constructs with high cell viability and measurable functional albumin and urea output. This methodology provides a general framework that can be adapted for future customization of hydrogels for biofabrication of a wide range of tissue construct types. PMID:27166839

  18. Bioprinting Cellularized Constructs Using a Tissue-specific Hydrogel Bioink.

    Science.gov (United States)

    Skardal, Aleksander; Devarasetty, Mahesh; Kang, Hyun-Wook; Seol, Young-Joon; Forsythe, Steven D; Bishop, Colin; Shupe, Thomas; Soker, Shay; Atala, Anthony

    2016-04-21

    Bioprinting has emerged as a versatile biofabrication approach for creating tissue engineered organ constructs. These constructs have potential use as organ replacements for implantation in patients, and also, when created on a smaller size scale as model "organoids" that can be used in in vitro systems for drug and toxicology screening. Despite development of a wide variety of bioprinting devices, application of bioprinting technology can be limited by the availability of materials that both expedite bioprinting procedures and support cell viability and function by providing tissue-specific cues. Here we describe a versatile hyaluronic acid (HA) and gelatin-based hydrogel system comprised of a multi-crosslinker, 2-stage crosslinking protocol, which can provide tissue specific biochemical signals and mimic the mechanical properties of in vivo tissues. Biochemical factors are provided by incorporating tissue-derived extracellular matrix materials, which include potent growth factors. Tissue mechanical properties are controlled combinations of PEG-based crosslinkers with varying molecular weights, geometries (linear or multi-arm), and functional groups to yield extrudable bioinks and final construct shear stiffness values over a wide range (100 Pa to 20 kPa). Using these parameters, hydrogel bioinks were used to bioprint primary liver spheroids in a liver-specific bioink to create in vitro liver constructs with high cell viability and measurable functional albumin and urea output. This methodology provides a general framework that can be adapted for future customization of hydrogels for biofabrication of a wide range of tissue construct types.

  19. Free radical scavenging injectable hydrogels for regenerative therapy

    International Nuclear Information System (INIS)

    Komeri, Remya; Thankam, Finosh Gnanaprakasam; Muthu, Jayabalan

    2017-01-01

    . • The PEAX-P hydrogel has suitable swelling, mechanical and degradation characterestics for injectable myocardial therapy. • The PEAX-P hydrogel scavenge 51% DPPH radical, 40% hydroxyl radicals and 41% nitrate radicals. • The in vitro studies confirm the protective effect of the present hydrogel on cardiomyoblast cells under oxidative stress. • The free electrons, hydrogen atoms and free water are responsible for the free radical scavenging property of hydrogel. • The present hydrogel is a potential candidate for myocardial regenerative therapy even with hypoxic microenvironment.

  20. Free radical scavenging injectable hydrogels for regenerative therapy

    Energy Technology Data Exchange (ETDEWEB)

    Komeri, Remya [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Polymer Science Division, BMT Wing, Thiruvananthapuram 695 012, Kerala State (India); Thankam, Finosh Gnanaprakasam [Dept. of Biomedical Sciences, Creighton University, 2500 California Plaza, Omaha NE68178 (United States); Muthu, Jayabalan, E-mail: mjayabalan52@gmail.com [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Polymer Science Division, BMT Wing, Thiruvananthapuram 695 012, Kerala State (India)

    2017-02-01

    . • The PEAX-P hydrogel has suitable swelling, mechanical and degradation characterestics for injectable myocardial therapy. • The PEAX-P hydrogel scavenge 51% DPPH radical, 40% hydroxyl radicals and 41% nitrate radicals. • The in vitro studies confirm the protective effect of the present hydrogel on cardiomyoblast cells under oxidative stress. • The free electrons, hydrogen atoms and free water are responsible for the free radical scavenging property of hydrogel. • The present hydrogel is a potential candidate for myocardial regenerative therapy even with hypoxic microenvironment.

  1. Aqueous biphasic systems containing PEG-based deep eutectic solvents for high-performance partitioning of RNA.

    Science.gov (United States)

    Zhang, Hongmei; Wang, Yuzhi; Zhou, Yigang; Xu, Kaijia; Li, Na; Wen, Qian; Yang, Qin

    2017-08-01

    In this work, 16 kinds of novel deep eutectic solvents (DESs) composed of polyethylene glycol (PEG) and quaternary ammonium salts, were coupled with Aqueous Biphasic Systems (ABSs) to extract RNA. The phase forming ability of ABSs were comprehensively evaluated, involving the effects of various proportions of DESs' components, carbon chain length and anions species of quaternary ammonium salts, average molecular weights of PEG and inorganic salts nature. Then the systems were applied in RNA extraction, and the results revealed that the extraction efficiency values were distinctly enhanced by relatively lower PEG content in DESs, smaller PEG molecular weights, longer carbon chain of quaternary ammonium salts and more hydrophobic inorganic salts. Then the systems composed of [TBAB][PEG600] and Na 2 SO 4 were utilized in the influence factor experiments, proving that the electrostatic interaction was the dominant force for RNA extraction. Therefore, back-extraction efficiency values ranging between 85.19% and 90.78% were obtained by adjusting the ionic strength. Besides, the selective separation of RNA and tryptophane (Trp) was successfully accomplished. It was found that 86.19% RNA was distributed in the bottom phase, while 72.02% Trp was enriched in the top phase in the novel ABSs. Finally, dynamic light scattering (DLS) and transmission electron microscope (TEM) were used to further investigate the extraction mechanism. The proposed method reveals the outstanding feasibility of the newly developed ABSs formed by PEG-based DESs and inorganic salts for the green extraction of RNA. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Design properties of hydrogel tissue-engineering scaffolds

    Science.gov (United States)

    Zhu, Junmin; Marchant, Roger E

    2011-01-01

    This article summarizes the recent progress in the design and synthesis of hydrogels as tissue-engineering scaffolds. Hydrogels are attractive scaffolding materials owing to their highly swollen network structure, ability to encapsulate cells and bioactive molecules, and efficient mass transfer. Various polymers, including natural, synthetic and natural/synthetic hybrid polymers, have been used to make hydrogels via chemical or physical crosslinking. Recently, bioactive synthetic hydrogels have emerged as promising scaffolds because they can provide molecularly tailored biofunctions and adjustable mechanical properties, as well as an extracellular matrix-like microenvironment for cell growth and tissue formation. This article addresses various strategies that have been explored to design synthetic hydrogels with extracellular matrix-mimetic bioactive properties, such as cell adhesion, proteolytic degradation and growth factor-binding. PMID:22026626

  3. In vitro and in vivo evaluation of a hydrogel reservoir as a continuous drug delivery system for inner ear treatment.

    Directory of Open Access Journals (Sweden)

    Mareike Hütten

    Full Text Available Fibrous tissue growth and loss of residual hearing after cochlear implantation can be reduced by application of the glucocorticoid dexamethasone-21-phosphate-disodium-salt (DEX. To date, sustained delivery of this agent to the cochlea using a number of pharmaceutical technologies has not been entirely successful. In this study we examine a novel way of continuous local drug application into the inner ear using a refillable hydrogel functionalized silicone reservoir. A PEG-based hydrogel made of reactive NCO-sP(EO-stat-PO prepolymers was evaluated as a drug conveying and delivery system in vitro and in vivo. Encapsulating the free form hydrogel into a silicone tube with a small opening for the drug diffusion resulted in delayed drug release but unaffected diffusion of DEX through the gel compared to the free form hydrogel. Additionally, controlled DEX release over several weeks could be demonstrated using the hydrogel filled reservoir. Using a guinea-pig cochlear trauma model the reservoir delivery of DEX significantly protected residual hearing and reduced fibrosis. As well as being used as a device in its own right or in combination with cochlear implants, the hydrogel-filled reservoir represents a new drug delivery system that feasibly could be replenished with therapeutic agents to provide sustained treatment of the inner ear.

  4. Thermo-responsive hydrogels for intravitreal injection and biomolecule release

    Science.gov (United States)

    Drapala, Pawel

    In this dissertation, we develop an injectable polymer system to enable localized and prolonged release of therapeutic biomolecules for improved treatment of Age-Related Macular Degeneration (AMD). Thermo-responsive hydrogels derived from N-isopropylacrylamide (NIPAAm) and cross-linked with poly(ethylene glycol) (PEG) poly(L-Lactic acid) (PLLA) copolymer were synthesized via free-radical polymerization. These materials were investigated for (a) phase change behavior, (b) in-vitro degradation, (c) capacity for controlled drug delivery, and (d) biocompatibility. The volume-phase transition temperature (VPTT) of the PNIPAAm- co-PEG-b-PLLA hydrogels was adjusted using hydrophilic and hydrophobic moieties so that it is ca. 33°C. These hydrogels did not initially show evidence of degradation at 37°C due to physical cross-links of collapsed PNIPAAm. Only after addition of glutathione chain transfer agents (CTA)s to the precursor did the collapsed hydrogels become fully soluble at 37°C. CTAs significantly affected the release kinetics of biomolecules; addition of 1.0 mg/mL glutathione to 3 mM cross-linker accelerated hydrogel degradation, resulting in 100% release in less than 2 days. This work also explored the effect of PEGylation in order to tether biomolecules to the polymer matrix. It was demonstrated that non-site-specific PEGylation can postpone the burst release of solutes (up to 10 days in hydrogels with 0.5 mg/mL glutathione). Cell viability assays showed that at least two 20-minute buffer extraction steps were needed to remove cytotoxic elements from the hydrogels. Clinically-used therapeutic biomolecules LucentisRTM and AvastinRTM were demonstrated to be both stable and bioactive after release form PNIPAAm-co-PEG-b-PLLA hydrogels. The thermo-responsive hydrogels presented here offer a promising platform for the localized delivery of proteins such as recombinant antibodies.

  5. Biodegradable Cellulose-based Hydrogels: Design and Applications

    Science.gov (United States)

    Sannino, Alessandro; Demitri, Christian; Madaghiele, Marta

    2009-01-01

    Hydrogels are macromolecular networks able to absorb and release water solutions in a reversible manner, in response to specific environmental stimuli. Such stimuli-sensitive behaviour makes hydrogels appealing for the design of ‘smart’ devices, applicable in a variety of technological fields. In particular, in cases where either ecological or biocompatibility issues are concerned, the biodegradability of the hydrogel network, together with the control of the degradation rate, may provide additional value to the developed device. This review surveys the design and the applications of cellulose-based hydrogels, which are extensively investigated due to the large availability of cellulose in nature, the intrinsic degradability of cellulose and the smart behaviour displayed by some cellulose derivatives.

  6. Biodegradable Cellulose-based Hydrogels: Design and Applications

    Directory of Open Access Journals (Sweden)

    Marta Madaghiele

    2009-04-01

    Full Text Available Hydrogels are macromolecular networks able to absorb and release water solutions in a reversible manner, in response to specific environmental stimuli. Such stimuli-sensitive behaviour makes hydrogels appealing for the design of ‘smart’ devices, applicable in a variety of technological fields. In particular, in cases where either ecological or biocompatibility issues are concerned, the biodegradability of the hydrogel network, together with the control of the degradation rate, may provide additional value to the developed device. This review surveys the design and the applications of cellulose-based hydrogels, which are extensively investigated due to the large availability of cellulose in nature, the intrinsic degradability of cellulose and the smart behaviour displayed by some cellulose derivatives.

  7. Processing Techniques and Applications of Silk Hydrogels in Bioengineering

    Directory of Open Access Journals (Sweden)

    Michael Floren

    2016-09-01

    Full Text Available Hydrogels are an attractive class of tunable material platforms that, combined with their structural and functional likeness to biological environments, have a diversity of applications in bioengineering. Several polymers, natural and synthetic, can be used, the material selection being based on the required functional characteristics of the prepared hydrogels. Silk fibroin (SF is an attractive natural polymer for its excellent processability, biocompatibility, controlled degradation, mechanical properties and tunable formats and a good candidate for the fabrication of hydrogels. Tremendous effort has been made to control the structural and functional characteristic of silk hydrogels, integrating novel biological features with advanced processing techniques, to develop the next generation of functional SF hydrogels. Here, we review the several processing methods developed to prepare advanced SF hydrogel formats, emphasizing a bottom-up approach beginning with critical structural characteristics of silk proteins and their behavior under specific gelation environments. Additionally, the preparation of SF hydrogel blends and other advanced formats will also be discussed. We conclude with a brief description of the attractive utility of SF hydrogels in relevant bioengineering applications.

  8. Targeted PEG-based bioconjugates enhance the cellular uptake and transport of a HIV-1 TAT nonapeptide.

    Science.gov (United States)

    Ramanathan, S; Qiu, B; Pooyan, S; Zhang, G; Stein, S; Leibowitz, M J; Sinko, P J

    2001-12-13

    We previously described the enhanced cell uptake and transport of R.I-K(biotin)-Tat9, a large ( approximately 1500 Da) peptidic inhibitor of HIV-1 Tat protein, via SMVT, the intestinal biotin transporter. The aim of the present study was to investigate the feasibility of targeting biotinylated PEG-based conjugates to SMVT in order to enhance cell uptake and transport of Tat9. The 29 kDa peptide-loaded bioconjugate (PEG:(R.I-Cys-K(biotin)-Tat9)8) used in these studies contained eight copies of R.I-K(biotin)-Tat9 appended to PEG by means of a cysteine linkage. The absorptive transport of biotin-PEG-3400 (0.6-100 microM) and the bioconjugate (0.1-30 microM) was studied using Caco-2 cell monolayers. Inhibition of biotin-PEG-3400 by positive controls (biotin, biocytin, and desthiobiotin) was also determined. Uptake of these two compounds was also determined in CHO cells transfected with human SMVT (CHO/hSMVT) and control cells (CHO/pSPORT) over the concentration ranges of 0.05-12.5 microM and 0.003-30 microM, respectively. Nonbiotinylated forms of these two compounds, PEG-3350 and PEG:(R.I-Cys-K-Tat9)8, were used in the control studies. Biotin-PEG-3400 transport was found to be concentration-dependent and saturable in Caco-2 cells (K(m)=6.61 microM) and CHO/hSMVT cells (K(m)=1.26 microM). Transport/uptake was significantly inhibited by positive control substrates of SMVT. PEG:(R.I-Cys-K(biotin)Tat9)8 also showed saturable transport kinetics in Caco-2 cells (K(m)=6.13 microM) and CHO/hSMVT cells (K(m)=8.19 microM). Maximal uptake in molar equivalents of R.I-Cys-K(biotin)Tat9 was 5.7 times greater using the conjugate versus the biotinylated peptide alone. Transport of the nonbiotinylated forms was significantly lower (PPEG-3400 and PEG:(R.I-Cys-K(biotin)Tat9)8 interact with human SMVT to enhance the cellular uptake and transport of these larger molecules and that targeted bioconjugates may have potential for enhancing the cellular uptake and transport of small peptide

  9. HLC/pullulan and pullulan hydrogels: their microstructure, engineering process and biocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xian [College of chemistry & materials science, Northwest University, Taibai North Road 229, Xi’an, Shaanxi 710069 (China); Shaanxi Key Laboratory of Degradable Biomedical Materials, Department of Chemical Engineering, Northwest University, Taibai North Road 229, Xi’an, Shaanxi 710069 (China); Xue, Wenjiao [Shannxi provincial institute of microbiology, Xi’ an 710043 (China); Liu, Yannan; Li, Weina [Shaanxi Key Laboratory of Degradable Biomedical Materials, Department of Chemical Engineering, Northwest University, Taibai North Road 229, Xi’an, Shaanxi 710069 (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, Department of Chemical Engineering, Northwest University, Taibai North Road 229, Xi’an, Shaanxi 710069 (China); Zhu, Chenhui [Shaanxi Key Laboratory of Degradable Biomedical Materials, Department of Chemical Engineering, Northwest University, Taibai North Road 229, Xi’an, Shaanxi 710069 (China); Wang, Yaoyu, E-mail: wyaoyu@nwu.edu.cn [College of chemistry & materials science, Northwest University, Taibai North Road 229, Xi’an, Shaanxi 710069 (China)

    2016-01-01

    New locally injectable biomaterials that are suitable for use as soft tissue fillers are needed to address a significant unmet medical need. In this study, we used pullulan and human-like collagen (HLC) based hydrogels with various molecular weights (MWs) in combination therapy against tissue defects. Briefly, pullulan was crosslinked with NaIO{sub 4} to form a pullulan hydrogel and then may coupled with HLC using the reaction between the –NH{sub 2} end-group of HLC and the –CHO group present on the aldehyde pullulan to form the HLC/pullulan hydrogel, wherein the NaIO{sub 4} acted as the crosslinking and oxidizing agent. The good miscibility of pullulan and HLC in the hydrogels was confirmed via Fourier transform infrared spectroscopy, scanning electron microscopy, compression testing, enzyme degradation testing, cell adhesions, live/dead staining and subcutaneous filling assays. Here, pullulan hydrogels with various MWs were fabricated and physicochemically characterized. Limitations of the pullulan hydrogels included inflammation, poor mechanical strength, and degradation. By contrast, the properties of the HLC/pullulan hydrogels strongly enhanced. The efficacy of these hydrogels was evaluated both in vitro and in vivo. Our results indicate that HLC/pullulan hydrogels may have therapeutic value as efficient soft tissue fillers, with reduced inflammation, improved cell adhesion and delayed hydrogel degradation. - Graphical abstract: The HLC/pullulan hydrogels were prepared by dialysis, wet granulation and UV radiation after various MWs of pullulan and HLC were crosslinked with NaIO{sub 4}, and injected subcutaneously into Kunming mouse. The formation of HLC/pullulan hydrogels is due to the amide bond linkage with the amino group of HLC and the aldehyde groups in pullulan aqueous media after crosslinking by NaIO{sub 4}. HLC/pullulan hydrogels may have therapeutic value as efficient soft tissue fillers, with reduced inflammation, improved cell adhesion and

  10. Biomimetic hydrogel materials

    Science.gov (United States)

    Bertozzi, Carolyn; Mukkamala, Ravindranath; Chen, Qing; Hu, Hopin; Baude, Dominique

    2000-01-01

    Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

  11. Antifouling properties of hydrogels

    International Nuclear Information System (INIS)

    Murosaki, Takayuki; Gong, Jian Ping; Ahmed, Nafees

    2011-01-01

    Marine sessile organisms easily adhere to submerged solids such as rocks, metals and plastics, but not to seaweeds and fishes, which are covered with soft and wet 'hydrogel'. Inspired by this fact, we have studied long-term antifouling properties of hydrogels against marine sessile organisms. Hydrogels, especially those containing hydroxy group and sulfonic group, show excellent antifouling activity against barnacles both in laboratory assays and in the marine environment. The extreme low settlement on hydrogels in vitro and in vivo is mainly caused by antifouling properties against the barnacle cypris. (topical review)

  12. Antifouling properties of hydrogels

    Directory of Open Access Journals (Sweden)

    Takayuki Murosaki, Nafees Ahmed and Jian Ping Gong

    2011-01-01

    Full Text Available Marine sessile organisms easily adhere to submerged solids such as rocks, metals and plastics, but not to seaweeds and fishes, which are covered with soft and wet 'hydrogel'. Inspired by this fact, we have studied long-term antifouling properties of hydrogels against marine sessile organisms. Hydrogels, especially those containing hydroxy group and sulfonic group, show excellent antifouling activity against barnacles both in laboratory assays and in the marine environment. The extreme low settlement on hydrogels in vitro and in vivo is mainly caused by antifouling properties against the barnacle cypris.

  13. Synthesis of PVA-Chitosan Hydrogels for Wound Dressing Using Gamma Irradiation. Part I: Radiation Degradation of Chitosan in Solid State and in Solution

    International Nuclear Information System (INIS)

    Mahlous, M.; Tahtat, D.; Benamer, S.; Nacer Khodja, A.; Larbi Youcef, S.

    2010-01-01

    Chitosan is a partially deacetylated product of chitin, a very abundant polysaccharide, existing in exoskeleton of crustaceans. It is a polymer consisting of glucosamine and N-acetylglucosamine units linked by β-1-4-glycosidic bonds. Chitosan, like others polysaccharides, such as cellulose derivatives, alginates and carrageenan is widely used in food, medicine and cosmetic fields. Chitosan presents a variety of distinctive properties, such as biocompatibility, biodegradability, nontoxicity and nonantigenicity. Chitosan obtained by the deacetylation of chitin has, generally, a high molecular weight, which limits its solubility in aqueous solvents. The reduction of its molecular weight by degradation is usually used in order to improve its water solubility. Water-soluble chitosan exhibit some specific properties, such as antifungal activity, antimicrobial activity and plant growth promotion. Among the methods that have been tried to produce low molecular weight chitosan, radiation processing is the most promising one, since the process is simple, it is carried out at room temperature and no purification of the product is required after processing

  14. Physically crosslinked composite hydrogels of PVA with natural macromolecules: structure, mechanical properties, and endothelial cell compatibility.

    Science.gov (United States)

    Liu, Y; Vrana, N E; Cahill, P A; McGuinness, G B

    2009-08-01

    Polyvinyl alcohol (PVA) hydrogels have been considered potentially suitable for applications as engineered blood vessels because of their structure and mechanical properties. However, PVA's hydrophilicity hinders its capacity to act as a substrate for cell attachment. As a remedy, PVA was blended with chitosan, gelatin, or starch, and hydrogels were formed by subjecting the solutions to freeze-thaw cycles followed by coagulation bath immersion. The structure-property relationships for these hydrogels were examined by measurement of their swelling, rehydration, degradation, and mechanical properties. For the case of pure PVA hydrogels, the equilibrium swelling ratio was used to predict the effect of freeze thaw cycles and coagulation bath on average molecular weights between crosslinks and on mesh size. For all hydrogels, trends for the reswelling ratio, which is indicative of the crosslinked polymer fraction, were consistent with relative tensile properties. The coagulation bath treatment increased the degradation resistance of the hydrogels significantly. The suitability of each hydrogel for cell attachment and proliferation was examined by protein adsorption and bovine vascular endothelial cell culture experiments. Protein adsorption and cell proliferation was highest on the PVA/gelatin hydrogels. This study demonstrates that the potential of PVA hydrogels for artificial blood vessel applications can be improved by the addition of natural polymers, and that freeze-thawing and coagulation bath treatment can be utilized for fine adjustment of the physical characteristics.

  15. Enzymatically crosslinked gelatin hydrogel promotes the proliferation of adipose tissue-derived stromal cells

    Directory of Open Access Journals (Sweden)

    Gang Yang

    2016-09-01

    Full Text Available Gelatin hydrogel crosslinked by microbial transglutaminase (mTG exhibits excellent performance in cell adhesion, proliferation, and differentiation. We examined the gelation time and gel strength of gelatin/mTG hydrogels in various proportions to investigate their physical properties and tested their degradation performances in vitro. Cell morphology and viability of adipose tissue-derived stromal cells (ADSCs cultured on the 2D gel surface or in 3D hydrogel encapsulation were evaluated by immunofluorescence staining. Cell proliferation was tested via Alamar Blue assay. To investigate the hydrogel effect on cell differentiation, the cardiac-specific gene expression levelsof Nkx2.5, Myh6, Gja1, and Mef2c in encapsulated ADSCs with or without cardiac induction medium were detected by real-time RT-PCR. Cell release from the encapsulated status and cell migration in a 3D hydrogel model were assessed in vitro. Results show that the gelatin/mTG hydrogels are not cytotoxic and that their mechanical properties are adjustable. Hydrogel degradation is related to gel concentration and the resident cells. Cell growth morphology and proliferative capability in both 2D and 3D cultures were mainly affected by gel concentration. PCR result shows that hydrogel modulus together with induction medium affects the cardiac differentiation of ADSCs. The cell migration experiment and subcutaneous implantation show that the hydrogels are suitable for cell delivery.

  16. Construction and characterization of a pure protein hydrogel for drug delivery application.

    Science.gov (United States)

    Xu, Xu; Xu, ZhaoKang; Yang, XiaoFeng; He, YanHao; Lin, Rong

    2017-02-01

    Injectable hydrogels have a variety of applications, including regenerative medicine, tissue engineering and controlled drug delivery. In this paper, we reported on a pure protein hydrogel based on tetrameric recombinant proteins for the potential drug delivery application. This protein hydrogel was formed instantly by simply mixing two recombinant proteins (ULD-TIP1 and ULD-GGGWRESAI) through the specific protein-peptide interaction. The protein hydrogel was characterized by rheology and scanning electron microscopy (SEM). In vitro cytotoxicity test indicated that the developed protein hydrogel had no apparent cytotoxicity against L-929 cells and HCEC cells after 48h incubation. The formed protein hydrogels was gradually degraded after incubation in phosphate buffered solution (PBS, pH=7.4) for a period of 144h study, as indicated by in vitro degradation test. Encapsulation of model drug (sodium diclofenac; DIC) were achieved by simple mixing of drugs with hydrogelator and the entrapped drugs was almost completely released from hydrogels within 24h via a diffusion manner. As a conclusion, the simple and mild preparation procedure and good biocompatibility of protein hydrogel would render its good promising candidate for drug delivery applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Fabrication of Hyaluronan-Poly(vinylphosphonic acid-Chitosan Hydrogel for Wound Healing Application

    Directory of Open Access Journals (Sweden)

    Dang Hoang Phuc

    2016-01-01

    Full Text Available A new hydrogel made of hyaluronan, poly(vinylphosphonic acid, and chitosan (HA/PVPA/CS hydrogel was fabricated and characterized to be used for skin wound healing application. Firstly, the component ratio of hydrogel was studied to optimize the reaction effectiveness. Next, its microstructure was observed by light microscope. The chemical interaction in hydrogel was evaluated by nuclear magnetic resonance spectroscopy and Fourier transform-infrared spectroscopy. Then, a study on its degradation rate was performed. After that, antibacterial activity of the hydrogel was examined by agar diffusion method. Finally, in vivo study was performed to evaluate hydrogel’s biocompatibility. The results showed that the optimized hydrogel had a three-dimensional highly porous structure with the pore size ranging from about 25 µm to less than 125 µm. Besides, with a degradation time of two weeks, it could give enough time for the formation of extracellular matrix framework during remodeling stages. Furthermore, the antibacterial test showed that hydrogel has antimicrobial activity against E. coli. Finally, in vivo study indicated that the hydrogel was not rejected by the immune system and could enhance wound healing process. Overall, HA/PVPA/CS hydrogel was successfully fabricated and results implied its potential for wound healing applications.

  18. Biodestruction of strongly swelling polymer hydrogels and its effect on the water retention capacity of soils

    Science.gov (United States)

    Smagin, A. V.; Sadovnikova, N. B.; Smagina, M. V.

    2014-06-01

    The biodestruction of strongly swelling polymer hydrogels (water adsorbing soil conditioners of the new generation) has been studied at the quantitative level using original mathematical models. In laboratory experiments, a relationship between the hydrogel degradation rate and the temperature has been obtained, and the effect of the biodestruction on the water retention curve of soil compositions with hydrogels (used as an index of their water retention capacity) has been assessed. From the automatic monitoring data of the temperature regime of soils, the potential biodestruction of hydrogels has been predicted for different climatic conditions. The loss of hydrogels during three months of the vegetation period because of destruction can exceed 30% of their initial content in irrigated agriculture under arid climatic conditions and more than 10% under humid climatic conditions. Thus, the biodestruction of hydrogels is one of the most important factors decreasing their efficiency under actual soil conditions.

  19. The rational design of a peptide-based hydrogel responsive to H2S.

    Science.gov (United States)

    Peltier, Raoul; Chen, Ganchao; Lei, Haipeng; Zhang, Mei; Gao, Liqian; Lee, Su Seong; Wang, Zuankai; Sun, Hongyan

    2015-12-18

    The development of hydrogels that are responsive to external stimuli in a well-controlled manner is important for numerous biomedical applications. Herein we reported the first example of a hydrogel responsive to hydrogen sulphide (H2S). H2S is an important gasotransmitter whose deregulation has been associated with a number of pathological conditions. Our hydrogel design is based on the functionalization of an ultrashort hydrogelating peptide sequence with an azidobenzyl moiety, which was reported to react with H2S selectively under physiological conditions. The resulting peptide was able to produce hydrogels at a concentration as low as 0.1 wt%. It could then be fully degraded in the presence of excess H2S. We envision that the novel hydrogel developed in this study may provide useful tools for biomedical research.

  20. Study On The Application Of Hydrogel Prepared By Radiation Technique For Fermentation Of Sawdust

    International Nuclear Information System (INIS)

    Le Thuy Trang; Nguyen Huynh Phuong Uyen; Vo Thu Ha; Le Quang Luan

    2011-01-01

    The super water-adsorption hydrogels was successfully preparation by radiation crosslinking CMC in paste condition and radiation grafting acrylic acid into starch. The hydrogel with 76.36% gel fraction and 91.13% swelling degree were obtained by irradiation of CMC 20% at 20 kGy, while the hydrogel with 65.3% gel fraction and 234 swelling degree was acrylic acid and starch at 4 kGy. The supplementation of hydrogels prepared by radiation technique showed a higher cellulose degradation effect of waste of cattle after fermenting 30 and 45 days. The optimum condition was determined by mixing 1% (w/w) dried hydrogel in 99% (w/w) waste of cattle. The fermented sawdust using hydrogel prepared by radiation technique showed a better effect on the growth of F1 Chinese cabbage (Brassica Pe-tsai Bailey L.). (author)

  1. Synthesis and characterization of an in situ forming hydrogel using tyramine conjugated high methoxyl gum tragacanth.

    Science.gov (United States)

    Tavakol, Moslem; Vasheghani-Farahani, Ebrahim; Mohammadifar, Mohammad Amin; Soleimani, Masoud; Hashemi-Najafabadi, Sameereh

    2016-02-01

    In this study, an enzyme catalyzed in situ forming hydrogel based on tyramine conjugated high methoxyl content gum tragacanth (TA-HMGT) was prepared and characterized. TA-HMGT was synthesized via heterogeneous ammonolysis of methyl ester groups of HMGT. Then, the hydrogel was prepared via horseradish peroxidase catalyzed coupling reaction in the presence of hydrogen peroxide. Hydrogel properties, such as gelation time, swelling/degradation behavior and rheological properties could be adjusted by tuning the gelation parameters and extent of tyramine conjugation. This system was a soft elastic hydrogel with appropriate biocompatibility. The fast gelation of the hydrogel is desirable for clinical applications. Also, in vitro bovine serum albumin release from the synthesized hydrogel showed good release profile with limited burst release. © The Author(s) 2015.

  2. Dextran/Albumin hydrogel sealant for Dacron(R) vascular prosthesis.

    Science.gov (United States)

    Lisman, Anna; Butruk, Beata; Wasiak, Iga; Ciach, Tomasz

    2014-05-01

    In this paper, the authors describe a novel type of hydrogel coating prepared from the copolymer of human serum albumin and oxidized dextran. The material was designed as a hydrogel sealant for polyester (Dacron®)-based vascular grafts. Dextran was chosen as a coating material due to its anti-thrombogenic properties. Prepared hydrogels were compared with similar, already known biomaterial made from gelatine with the same cross-linking agent. Obtained hydrogels, prepared from various ratios of oxidized dextran/albumin or oxidized dextran/gelatine, showed different cross-linking densities, which caused differences in swelling, degradation rate and mechanical properties. Permeability tests confirmed the complete tightness of the hydrogel-modified prosthesis. Results showed that application of the hydrogel coating provided leakage-free prosthesis and eliminated the need of pre-clotting.

  3. Hydrogel formulation determines cell fate of fetal and adult neural progenitor cells

    Directory of Open Access Journals (Sweden)

    Emily R. Aurand

    2014-01-01

    Full Text Available Hydrogels provide a unique tool for neural tissue engineering. These materials can be customized for certain functions, i.e. to provide cell/drug delivery or act as a physical scaffold. Unfortunately, hydrogel complexities can negatively impact their biocompatibility, resulting in unintended consequences. These adverse effects may be combated with a better understanding of hydrogel chemical, physical, and mechanical properties, and how these properties affect encapsulated neural cells. We defined the polymerization and degradation rates and compressive moduli of 25 hydrogels formulated from different concentrations of hyaluronic acid (HA and poly(ethylene glycol (PEG. Changes in compressive modulus were driven primarily by the HA concentration. The in vitro biocompatibility of fetal-derived (fNPC and adult-derived (aNPC neural progenitor cells was dependent on hydrogel formulation. Acute survival of fNPC benefited from hydrogel encapsulation. NPC differentiation was divergent: fNPC differentiated into mostly glial cells, compared with neuronal differentiation of aNPC. Differentiation was influenced in part by the hydrogel mechanical properties. This study indicates that there can be a wide range of HA and PEG hydrogels compatible with NPC. Additionally, this is the first study comparing hydrogel encapsulation of NPC derived from different aged sources, with data suggesting that fNPC and aNPC respond dissimilarly within the same hydrogel formulation.

  4. Live RB51 vaccine lyophilized hydrogel formulations with increased shelf life for practical ballistic delivery

    Science.gov (United States)

    Ballistic delivery capability is essential to delivering vaccines and other therapeutics effectively to both livestock and wildlife in many global scenarios. Here, lyophilized poly(ethylene glycol) (PEG)-glycolide dimethacrylate crosslinked but degradable hydrogels were assessed as payload vehicles ...

  5. Sodium alginate/gelatin with silica nanoparticles a novel hydrogel for 3D printing

    Science.gov (United States)

    Soni, Raghav; Roopavath, Uday Kiran; Mahanta, Urbashi; Deshpande, A. S.; Rath, S. N.

    2018-05-01

    Sodium alginate/gelatin hydrogels are promising materials for 3D bio-printing due to its good biocompatibility and biodegradability. Gelatin is used for thermal crosslinking and its cell adhesion properties. Hence patient specific sodium alginate/gelatin hydrogel scaffolds can be bio-fabricated in a temperature range of 4-14 oC. In this study we made an attempt to introduce silica (SiO2) nanoparticles in the polymer network of sodium alginate (2.5%)/gelatin (8%) hydrogel at different concentrations (w/v) as 0%, 1.25%, 2.5%, 5%, and 7.5%. The effect of silica nanoparticles on viscosity, swelling behavior, and degradation rate are analyzed. Hydrogels with 5% silica nanoparticles show significantly less swelling and degradation when compared to other concentrations. The viscosity of the hydrogels gradually increases up to 5% addition of silica nanoparticles enhancing the stability of 3D printed structures.

  6. Polypeptide based hydrogels

    OpenAIRE

    Hanay, Saltuk

    2018-01-01

    There is a need for biocompatible, biodegradable, 3-D printable and stable hydrogels especially in the areas of tissue engineering, drug delivery, bio-sensing technologies and antimicrobial coatings. The main aim of this Ph.D. work was to fabricate polypeptide based hydrogel which may find a potential application in those fields. Focusing on tyrosine or tryptophan-containing copolypeptides prepared by NCarboxyanhydride (NCA) polymerizations, three different crosslinking strategies have been t...

  7. Biomimetic hydrogel loaded with silk and l-proline for tissue engineering and wound healing applications.

    Science.gov (United States)

    Thangavel, Ponrasu; Ramachandran, Balaji; Kannan, Ramya; Muthuvijayan, Vignesh

    2017-08-01

    The aim of this article was to develop silk protein (SF) and l-proline (LP) loaded chitosan-(CS) based hydrogels via physical cross linking for tissue engineering and wound healing applications. Silk fibroin, a biodegradable and biocompatible protein, and l-proline, an important imino acid that is required for collagen synthesis, were added to chitosan to improve the wound healing properties of the hydrogel. Characterization of these hydrogels revealed that CS/SF/LP hydrogels were blended properly and LP incorporated hydrogels showed excellent thermal stability and good surface morphology. Swelling study showed the water holding efficiency of the hydrogels to provide enough moisture at the wound surface. In vitro biodegradation results demonstrated that the hydrogels had good degradation rate in PBS with lysozyme. LP loaded hydrogels showed approximately a twofold increase in antioxidant activity. In vitro cytocompatibility studies using NIH 3T3 L1 cells showed increased cell viability (p Cell adhesion on SF and LP hydrogels were observed using SEM and compared to CS hydrogel. LP incorporation showed 74-78% of wound closure compared to 35% for CS/SF and 3% for CS hydrogels at 48 h. These results suggest that incorporation of LP can significantly accelerate wound healing process compared to pure CS and SF-loaded CS hydrogels. Hence, CS/LP hydrogels could be a potential wound dressing material for the enhanced wound tissue regeneration and repair. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1401-1408, 2017. © 2016 Wiley Periodicals, Inc.

  8. An Optimized Injectable Hydrogel Scaffold Supports Human Dental Pulp Stem Cell Viability and Spreading

    Directory of Open Access Journals (Sweden)

    T. D. Jones

    2016-01-01

    Full Text Available Introduction. HyStem-C™ is a commercially available injectable hydrogel composed of polyethylene glycol diacrylate (PEGDA, hyaluronan (HA, and gelatin (Gn. These components can be mechanically tuned to enhance cell viability and spreading. Methods. The concentration of PEGDA with an added disulfide bond (PEGSSDA was varied from 0.5 to 8.0% (w/v to determine the optimal concentration for injectable clinical application. We evaluated the cell viability of human dental pulp stem cells (hDPSCs embedded in 2% (w/v PEGSSDA-HA-Gn hydrogels. Volume ratios of HA : Gn from 100 : 0 to 25 : 75 were varied to encourage hDPSC spreading. Fibronectin (Fn was added to our model to determine the effect of extracellular matrix protein concentration on hDPSC behavior. Results. Our preliminary data suggests that the hydrogel gelation time decreased as the PEGSSDA cross-linker concentration increased. The PEGSSDA-HA-Gn was biocompatible with hDPSCs, and increased ratios of HA : Gn enhanced cell viability for 14 days. Additionally, cell proliferation with added fibronectin increased significantly over time at concentrations of 1.0 and 10.0 μg/mL in PEGDA-HA-Gn hydrogels, while cell spreading significantly increased at Fn concentrations of 0.1 μg/mL. Conclusions. This study demonstrates that PEG-based injectable hydrogels maintain hDPSC viability and facilitate cell spreading, mainly in the presence of extracellular matrix (ECM proteins.

  9. Automation of 3D cell culture using chemically defined hydrogels.

    Science.gov (United States)

    Rimann, Markus; Angres, Brigitte; Patocchi-Tenzer, Isabel; Braum, Susanne; Graf-Hausner, Ursula

    2014-04-01

    Drug development relies on high-throughput screening involving cell-based assays. Most of the assays are still based on cells grown in monolayer rather than in three-dimensional (3D) formats, although cells behave more in vivo-like in 3D. To exemplify the adoption of 3D techniques in drug development, this project investigated the automation of a hydrogel-based 3D cell culture system using a liquid-handling robot. The hydrogel technology used offers high flexibility of gel design due to a modular composition of a polymer network and bioactive components. The cell inert degradation of the gel at the end of the culture period guaranteed the harmless isolation of live cells for further downstream processing. Human colon carcinoma cells HCT-116 were encapsulated and grown in these dextran-based hydrogels, thereby forming 3D multicellular spheroids. Viability and DNA content of the cells were shown to be similar in automated and manually produced hydrogels. Furthermore, cell treatment with toxic Taxol concentrations (100 nM) had the same effect on HCT-116 cell viability in manually and automated hydrogel preparations. Finally, a fully automated dose-response curve with the reference compound Taxol showed the potential of this hydrogel-based 3D cell culture system in advanced drug development.

  10. Injectable dual redox responsive diselenide-containing poly(ethylene glycol) hydrogel.

    Science.gov (United States)

    Gong, Chu; Shan, Meng; Li, Bingqiang; Wu, Guolin

    2017-09-01

    An injectable dual redox responsive diselenide-containing poly(ethylene glycol) (PEG) hydrogel was successfully developed by combining the conceptions of injectable hydrogels and dual redox responsive diselenides. In the first step, four-armed PEG was modified with N-hydroxysuccinimide (NHS)-activated esters and thereafter, crosslinked by selenocystamine crosslinkers to form injectable hydrogels via the rapid reaction between NHS-activated esters and amino groups. The cross-sectional morphology, mechanical properties, and crosslinking modes of hydrogels were well characterized via scanning electron microscope (SEM), rheological measurements, and Fourier transform infrared spectra, respectively. In addition, the oxidation- and reduction-responsive degradation behaviors of hydrogels were observed and analyzed. The model drug, rhodamine B, was encapsulated in the hydrogel. The drug-loaded hydrogel exhibited a dual redox responsive release profile, which was consistent with the degradation experiments. The results of all experiments indicated that the formulated injectable dual redox responsive diselenide-containing PEG hydrogel can have potential applications in various biomedical fields such as drug delivery and stimuli-responsive drug release. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2451-2460, 2017. © 2017 Wiley Periodicals, Inc.

  11. Cartilage-like mechanical properties of poly (ethylene glycol)-diacrylate hydrogels.

    Science.gov (United States)

    Nguyen, Quynhhoa T; Hwang, Yongsung; Chen, Albert C; Varghese, Shyni; Sah, Robert L

    2012-10-01

    Hydrogels prepared from poly-(ethylene glycol) (PEG) have been used in a variety of studies of cartilage tissue engineering. Such hydrogels may also be useful as a tunable mechanical material for cartilage repair. Previous studies have characterized the chemical and mechanical properties of PEG-based hydrogels, as modulated by precursor molecular weight and concentration. Cartilage mechanical properties vary substantially, with maturation, with depth from the articular surface, in health and disease, and in compression and tension. We hypothesized that PEG hydrogels could mimic a broad range of the compressive and tensile mechanical properties of articular cartilage. The objective of this study was to characterize the mechanical properties of PEG hydrogels over a broad range and with reference to articular cartilage. In particular, we assessed the effects of PEG precursor molecular weight (508 Da, 3.4 kDa, 6 kDa, and 10 kDa) and concentration (10-40%) on swelling property, equilibrium confined compressive modulus (H(A0)), compressive dynamic stiffness, and hydraulic permeability (k(p0)) of PEG hydrogels in static/dynamic confined compression tests, and equilibrium tensile modulus (E(ten)) in tension tests. As molecular weight of PEG decreased and concentration increased, hydrogels exhibited a decrease in swelling ratio (31.5-2.2), an increase in H(A0) (0.01-2.46 MPa) and E(ten) (0.02-3.5 MPa), an increase in dynamic compressive stiffness (0.055-42.9 MPa), and a decrease in k(p0) (1.2 × 10(-15) to 8.5 × 10(-15) m(2)/(Pa s)). The frequency-dependence of dynamic compressive stiffness amplitude and phase, as well as the strain-dependence of permeability, were typical of the time- and strain-dependent mechanical behavior of articular cartilage. H(A0) and E(ten) were positively correlated with the final PEG concentration, accounting for swelling. These results indicate that PEG hydrogels can be prepared to mimic many of the static and dynamic mechanical

  12. Biomedical hydrogels biochemistry, manufacture and medical applications

    CERN Document Server

    Rimmer, Steve

    2011-01-01

    Hydrogels are very important for biomedical applications because they can be chemically manipulated to alter and control the hydrogel's interaction with cells and tissues. Their flexibility and high water content is similar to that of natural tissue, making them extremely suitable for biomaterials applications. Biomedical hydrogels explores the diverse range and use of hydrogels, focusing on processing methods and novel applications in the field of implants and prostheses. Part one of this book concentrates on the processing of hydrogels, covering hydrogel swelling behaviour, superabsorbent cellulose-based hydrogels and regulation of novel hydrogel products, as well as chapters focusing on the structure and properties of hydrogels and different fabrication technologies. Part two covers existing and novel applications of hydrogels, including chapters on spinal disc and cartilage replacement implants, hydrogels for ophthalmic prostheses and hydrogels for wound healing applications. The role of hydrogels in imag...

  13. Chitosan-containing hydrogel wound dressings prepared by radiation technique

    International Nuclear Information System (INIS)

    Mozalewska, Wiktoria; Czechowska-Biskup, Renata; Olejnik, Alicja K.; Wach, Radoslaw A.; Ulański, Piotr; Rosiak, Janusz M.

    2017-01-01

    The aim of the study was to develop an antimicrobial hydrogel wound dressing by means of radiation-initiated crosslinking of hydrophilic polymers, i.e. by well-established technology comprising gel manufacturing and its sterilization in one process. The approach included admixture of chitosan of relatively low molecular weight dissolved in lactic acid (LA) into the initial regular components of the conventional hydrogel dressing based on poly(N-vinyl pyrrolidone) (PVP) and agar. Molecular weight of chitosan was regulated by radiation-initiated degradation in the range of 39–132 kg mol −1 . Optimum total concentration of LA in the resultant hydrogel dressing was evaluated as 0.05 mol dm −3 , that is ca. 0.5%. Presence of LA in the system influenced essential radiation and technological parameters of hydrogel manufacturing. The setting temperature of the pre-hydrogel mixture, resulting from agar ability to congeal, was reduced with LA concentration, yet remained significantly above the room temperature. 0.5% of chitosan was effectively dissolved in aqueous solution of lactic acid due to its pH (lower than 5.5). Radiation parameters of PVP crosslinking in the presence of LA, as determined with generalized Charlesby–Pinner equation, were reflected in slight reduction of the maximum gel fraction and increase in gelation dose and in the factor comparing yields of scission to crosslinking. Nevertheless, essentially physical characteristics of the hydrogel was not affected, except for somewhat increased water uptake capacity, what in turn improves functionality of the dressing as extensive exudate for the wound can be efficiently absorbed. Preliminary microbiological studies showed antimicrobial character of the chitosan-containing hydrogel towards Gram-positive bacterial strain. - Highlights: • Radiation synthesis of bioactive hydrogel wound dressing based on PVP. • Sol-gel analysis, radiation yield of crosslinking and degradation, gel fraction.

  14. Cell-laden hydrogels for osteochondral and cartilage tissue engineering.

    Science.gov (United States)

    Yang, Jingzhou; Zhang, Yu Shrike; Yue, Kan; Khademhosseini, Ali

    2017-07-15

    Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered artificial matrices that can replace the damaged regions and promote tissue regeneration. Hydrogels are emerging as a promising class of biomaterials for both soft and hard tissue regeneration. Many critical properties of hydrogels, such as mechanical stiffness, elasticity, water content, bioactivity, and degradation, can be rationally designed and conveniently tuned by proper selection of the material and chemistry. Particularly, advances in the development of cell-laden hydrogels have opened up new possibilities for cell therapy. In this article, we describe the problems encountered in this field and review recent progress in designing cell-hydrogel hybrid constructs for promoting the reestablishment of osteochondral/cartilage tissues. Our focus centers on the effects of hydrogel type, cell type, and growth factor delivery on achieving efficient chondrogenesis and osteogenesis. We give our perspective on developing next-generation matrices with improved physical and biological properties for osteochondral/cartilage tissue engineering. We also highlight recent advances in biomanufacturing technologies (e.g. molding, bioprinting, and assembly) for fabrication of hydrogel-based osteochondral and cartilage constructs with complex compositions and microarchitectures to mimic their native counterparts. Despite tremendous advances in the field of regenerative medicine, it still remains challenging to repair the osteochondral interface and full-thickness articular cartilage defects. This inefficiency largely originates from the lack of appropriate tissue-engineered biomaterials that replace the damaged regions and promote tissue regeneration. Cell-laden hydrogel systems have emerged as a promising tissue

  15. The self-crosslinking smart hyaluronic acid hydrogels as injectable three-dimensional scaffolds for cells culture.

    Science.gov (United States)

    Bian, Shaoquan; He, Mengmeng; Sui, Junhui; Cai, Hanxu; Sun, Yong; Liang, Jie; Fan, Yujiang; Zhang, Xingdong

    2016-04-01

    Although the disulfide bond crosslinked hyaluronic acid hydrogels have been reported by many research groups, the major researches were focused on effectively forming hydrogels. However, few researchers paid attention to the potential significance of controlling the hydrogel formation and degradation, improving biocompatibility, reducing the toxicity of exogenous and providing convenience to the clinical operations later on. In this research, the novel controllable self-crosslinking smart hydrogels with in-situ gelation property was prepared by a single component, the thiolated hyaluronic acid derivative (HA-SH), and applied as a three-dimensional scaffold to mimic native extracellular matrix (ECM) for the culture of fibroblasts cells (L929) and chondrocytes. A series of HA-SH hydrogels were prepared depending on different degrees of thiol substitution (ranging from 10 to 60%) and molecule weights of HA (0.1, 0.3 and 1.0 MDa). The gelation time, swelling property and smart degradation behavior of HA-SH hydrogel were evaluated. The results showed that the gelation and degradation time of hydrogels could be controlled by adjusting the component of HA-SH polymers. The storage modulus of HA-SH hydrogels obtained by dynamic modulus analysis (DMA) could be up to 44.6 kPa. In addition, HA-SH hydrogels were investigated as a three-dimensional scaffold for the culture of fibroblasts cells (L929) and chondrocytes cells in vitro and as an injectable hydrogel for delivering chondrocytes cells in vivo. These results illustrated that HA-SH hydrogels with controllable gelation process, intelligent degradation behavior, excellent biocompatibility and convenient operational characteristics supplied potential clinical application capacity for tissue engineering and regenerative medicine. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Graphene hydrogels with embedded metal nanoparticles as efficient catalysts in 4-nitrophenol reduction and methylene blue decolorization

    Directory of Open Access Journals (Sweden)

    Żelechowska Kamila

    2016-12-01

    Full Text Available Synthesis and characterization of the graphene hydrogels with three different metallic nanoparticles, that is Au, Ag and Cu, respectively is presented. Synthesized in a one-pot approach graphene hydrogels with embedded metallic nanoparticles were tested as heterogeneous catalysts in a model reaction of 4-nitrophenol reduction. The highest activity was obtained for graphene hydrogel with Cu nanoparticles and additional reaction of methylene blued degradation was evaluated using this system. The obtained outstanding catalytic activity arises from the synergistic effect of graphene and metallic nanoparticles. The hydrogel form of the catalyst benefits in the easiness in separation from the reaction mixture (for example using tweezers and reusability.

  17. Improvement of mechanical properties of hydrogel by irradiation of polymers in aqueous solution with κ-carrageenan

    International Nuclear Information System (INIS)

    Makuuchi, K.; Yoshii, F.; Zhai, M.

    2000-01-01

    Predominate radiation reaction of κ-carrageenan (KC) hydrogel is the main chain scission of KC. The gel strength of KC hydrogel decreased with increasing irradiation dose. However, KC was found to enhances the radiation crosslinking of synthetic water-soluble polymer (SWSP) such as poly(ethylene oxide) (PEO) and poly(N-vinylpyrolidone) (PVP) in aqueous solution. The gel strength of SWSP hydrogel increased with increasing dose when KC was blended. Probably the radiation degraded KC radicals are recombined with radicals of PVP and PEO. The hydrogel thus prepared absorbs huge amounts of water due to the presence of strong hydrophilic -OSO 3 - groups in KC. (author)

  18. Improvement of mechanical properties of hydrogel by irradiation of polymers in aqueous solution with {kappa}-carrageenan

    Energy Technology Data Exchange (ETDEWEB)

    Makuuchi, K.; Yoshii, F. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Aranilla, C.T. [Philippine Nuclear Research Institute, Diliman, Quezon (Philippines); Zhai, M. [Department of Technical Physics, Peking Univ., Beijing (China)

    2000-03-01

    Predominate radiation reaction of {kappa}-carrageenan (KC) hydrogel is the main chain scission of KC. The gel strength of KC hydrogel decreased with increasing irradiation dose. However, KC was found to enhances the radiation crosslinking of synthetic water-soluble polymer (SWSP) such as poly(ethylene oxide) (PEO) and poly(N-vinylpyrolidone) (PVP) in aqueous solution. The gel strength of SWSP hydrogel increased with increasing dose when KC was blended. Probably the radiation degraded KC radicals are recombined with radicals of PVP and PEO. The hydrogel thus prepared absorbs huge amounts of water due to the presence of strong hydrophilic -OSO{sub 3}{sup -} groups in KC. (author)

  19. Prodrugs as self-assembled hydrogels: a new paradigm for biomaterials.

    Science.gov (United States)

    Vemula, Praveen Kumar; Wiradharma, Nikken; Ankrum, James A; Miranda, Oscar R; John, George; Karp, Jeffrey M

    2013-12-01

    Prodrug-based self-assembled hydrogels represent a new class of active biomaterials that can be harnessed for medical applications, in particular the design of stimuli responsive drug delivery devices. In this approach, a promoiety is chemically conjugated to a known-drug to generate an amphiphilic prodrug that is capable of forming self-assembled hydrogels. Prodrug-based self-assembled hydrogels are advantageous as they alter the solubility of the drug, enhance drug loading, and eliminate the use of harmful excipients. In addition, self-assembled prodrug hydrogels can be designed to undergo controlled drug release or tailored degradation in response to biological cues. Herein we review the development of prodrug-based self-assembled hydrogels as an emerging class of biomaterials that overcome several common limitations encountered in conventional drug delivery. Published by Elsevier Ltd.

  20. Polymers in the gut compress the colonic mucus hydrogel.

    Science.gov (United States)

    Datta, Sujit S; Preska Steinberg, Asher; Ismagilov, Rustem F

    2016-06-28

    Colonic mucus is a key biological hydrogel that protects the gut from infection and physical damage and mediates host-microbe interactions and drug delivery. However, little is known about how its structure is influenced by materials it comes into contact with regularly. For example, the gut abounds in polymers such as dietary fibers or administered therapeutics, yet whether such polymers interact with the mucus hydrogel, and if so, how, remains unclear. Although several biological processes have been identified as potential regulators of mucus structure, the polymeric composition of the gut environment has been ignored. Here, we demonstrate that gut polymers do in fact regulate mucus hydrogel structure, and that polymer-mucus interactions can be described using a thermodynamic model based on Flory-Huggins solution theory. We found that both dietary and therapeutic polymers dramatically compressed murine colonic mucus ex vivo and in vivo. This behavior depended strongly on both polymer concentration and molecular weight, in agreement with the predictions of our thermodynamic model. Moreover, exposure to polymer-rich luminal fluid from germ-free mice strongly compressed the mucus hydrogel, whereas exposure to luminal fluid from specific-pathogen-free mice-whose microbiota degrade gut polymers-did not; this suggests that gut microbes modulate mucus structure by degrading polymers. These findings highlight the role of mucus as a responsive biomaterial, and reveal a mechanism of mucus restructuring that must be integrated into the design and interpretation of studies involving therapeutic polymers, dietary fibers, and fiber-degrading gut microbes.

  1. Engineering Hydrogel Microenvironments to Recapitulate the Stem Cell Niche.

    Science.gov (United States)

    Madl, Christopher M; Heilshorn, Sarah C

    2018-06-04

    Stem cells are a powerful resource for many applications including regenerative medicine, patient-specific disease modeling, and toxicology screening. However, eliciting the desired behavior from stem cells, such as expansion in a naïve state or differentiation into a particular mature lineage, remains challenging. Drawing inspiration from the native stem cell niche, hydrogel platforms have been developed to regulate stem cell fate by controlling microenvironmental parameters including matrix mechanics, degradability, cell-adhesive ligand presentation, local microstructure, and cell-cell interactions. We survey techniques for modulating hydrogel properties and review the effects of microenvironmental parameters on maintaining stemness and controlling differentiation for a variety of stem cell types. Looking forward, we envision future hydrogel designs spanning a spectrum of complexity, ranging from simple, fully defined materials for industrial expansion of stem cells to complex, biomimetic systems for organotypic cell culture models.

  2. About the Sterilization of Chitosan Hydrogel Nanoparticles.

    Science.gov (United States)

    Galante, Raquel; Rediguieri, Carolina F; Kikuchi, Irene Satiko; Vasquez, Pablo A S; Colaço, Rogério; Serro, Ana Paula; Pinto, Terezinha J A

    2016-01-01

    In the last years, nanostructured biomaterials have raised a great interest as platforms for delivery of drugs, genes, imaging agents and for tissue engineering applications. In particular, hydrogel nanoparticles (HNP) associate the distinctive features of hydrogels (high water uptake capacity, biocompatibility) with the advantages of being possible to tailor its physicochemical properties at nano-scale to increase solubility, immunocompatibility and cellular uptake. In order to be safe, HNP for biomedical applications, such as injectable or ophthalmic formulations, must be sterile. Literature is very scarce with respect to sterilization effects on nanostructured systems, and even more in what concerns HNP. This work aims to evaluate the effect and effectiveness of different sterilization methods on chitosan (CS) hydrogel nanoparticles. In addition to conventional methods (steam autoclave and gamma irradiation), a recent ozone-based method of sterilization was also tested. A model chitosan-tripolyphosphate (TPP) hydrogel nanoparticles (CS-HNP), with a broad spectrum of possible applications was produced and sterilized in the absence and in the presence of protective sugars (glucose and mannitol). Properties like size, zeta potential, absorbance, morphology, chemical structure and cytotoxicity were evaluated. It was found that the CS-HNP degrade by autoclaving and that sugars have no protective effect. Concerning gamma irradiation, the formation of agglomerates was observed, compromising the suspension stability. However, the nanoparticles resistance increases considerably in the presence of the sugars. Ozone sterilization did not lead to significant physical adverse effects, however, slight toxicity signs were observed, contrarily to gamma irradiation where no detectable changes on cells were found. Ozonation in the presence of sugars avoided cytotoxicity. Nevertheless, some chemical alterations were observed in the nanoparticles.

  3. About the Sterilization of Chitosan Hydrogel Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Raquel Galante

    Full Text Available In the last years, nanostructured biomaterials have raised a great interest as platforms for delivery of drugs, genes, imaging agents and for tissue engineering applications. In particular, hydrogel nanoparticles (HNP associate the distinctive features of hydrogels (high water uptake capacity, biocompatibility with the advantages of being possible to tailor its physicochemical properties at nano-scale to increase solubility, immunocompatibility and cellular uptake. In order to be safe, HNP for biomedical applications, such as injectable or ophthalmic formulations, must be sterile. Literature is very scarce with respect to sterilization effects on nanostructured systems, and even more in what concerns HNP. This work aims to evaluate the effect and effectiveness of different sterilization methods on chitosan (CS hydrogel nanoparticles. In addition to conventional methods (steam autoclave and gamma irradiation, a recent ozone-based method of sterilization was also tested. A model chitosan-tripolyphosphate (TPP hydrogel nanoparticles (CS-HNP, with a broad spectrum of possible applications was produced and sterilized in the absence and in the presence of protective sugars (glucose and mannitol. Properties like size, zeta potential, absorbance, morphology, chemical structure and cytotoxicity were evaluated. It was found that the CS-HNP degrade by autoclaving and that sugars have no protective effect. Concerning gamma irradiation, the formation of agglomerates was observed, compromising the suspension stability. However, the nanoparticles resistance increases considerably in the presence of the sugars. Ozone sterilization did not lead to significant physical adverse effects, however, slight toxicity signs were observed, contrarily to gamma irradiation where no detectable changes on cells were found. Ozonation in the presence of sugars avoided cytotoxicity. Nevertheless, some chemical alterations were observed in the nanoparticles.

  4. Synthesis and characterization of hyaluronic acid/human-like collagen hydrogels

    International Nuclear Information System (INIS)

    Zhang, Jingjing; Ma, Xiaoxuan; Fan, Daidi; Zhu, Chenhui; Deng, Jianjun; Hui, Junfeng; Ma, Pei

    2014-01-01

    Injectable hydrogel plays an important role in soft tissue filling and repair. We report an injectable hydrogel based on hyaluronic acid (HA) and human-like collagen (HLC), both with favorable biocompatibility and biodegradability. These two types of biomacromolecules were crosslinked with 1,4-butanediol diglycidyl ether to form a three-dimensional network. The redundant crosslinker was removed by dialysis and distillation. An HA-based hydrogel prepared by the same method was used as a control. The cytocompatibility was studied with a Cell Counting Kit-8 (CCK-8) test. Carbazole colorimetry was used to analyze the in vitro degradation rate. The histocompatibility was evaluated by hematoxylin and eosin (H and E) staining analysis and immunohistochemical analysis. The CCK-8 assay demonstrated that the HA/HLC hydrogel was less cytotoxic than the HA-based hydrogel and could promote baby hamster kidney cell (BHK) proliferation. The cell adhesion indicated that BHK could grow well on the surface of the materials and maintain good cell viability. The in vitro degradation test showed that the HA/HLC hydrogel had a longer degradation time and an excellent antienzyme ability. In vivo injection showed that there was little inflammatory response to HA/HLC after 1, 2, and 4 weeks. Therefore, the HA/HLC hydrogel is a promising biomaterial for soft tissue filling and repair. - Highlights: • Human-like collagen was used with hyaluronic acid to prepare soft tissue filling meterials. • 1,4-Butanediol diglycidyl ether (BDDE) was introduced to treat the hydrogels. • The addition of human-like collagen could improve the biological properties of hydrogels

  5. Synthesis and characterization of hyaluronic acid/human-like collagen hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingjing; Ma, Xiaoxuan, E-mail: xiaoxuanma@163.com; Fan, Daidi, E-mail: fandaidi@nwu.edu.cn; Zhu, Chenhui; Deng, Jianjun; Hui, Junfeng; Ma, Pei

    2014-10-01

    Injectable hydrogel plays an important role in soft tissue filling and repair. We report an injectable hydrogel based on hyaluronic acid (HA) and human-like collagen (HLC), both with favorable biocompatibility and biodegradability. These two types of biomacromolecules were crosslinked with 1,4-butanediol diglycidyl ether to form a three-dimensional network. The redundant crosslinker was removed by dialysis and distillation. An HA-based hydrogel prepared by the same method was used as a control. The cytocompatibility was studied with a Cell Counting Kit-8 (CCK-8) test. Carbazole colorimetry was used to analyze the in vitro degradation rate. The histocompatibility was evaluated by hematoxylin and eosin (H and E) staining analysis and immunohistochemical analysis. The CCK-8 assay demonstrated that the HA/HLC hydrogel was less cytotoxic than the HA-based hydrogel and could promote baby hamster kidney cell (BHK) proliferation. The cell adhesion indicated that BHK could grow well on the surface of the materials and maintain good cell viability. The in vitro degradation test showed that the HA/HLC hydrogel had a longer degradation time and an excellent antienzyme ability. In vivo injection showed that there was little inflammatory response to HA/HLC after 1, 2, and 4 weeks. Therefore, the HA/HLC hydrogel is a promising biomaterial for soft tissue filling and repair. - Highlights: • Human-like collagen was used with hyaluronic acid to prepare soft tissue filling meterials. • 1,4-Butanediol diglycidyl ether (BDDE) was introduced to treat the hydrogels. • The addition of human-like collagen could improve the biological properties of hydrogels.

  6. Foamed oligo(poly(ethylene glycol)fumarate) hydrogels as versatile prefabricated scaffolds for tissue engineering.

    Science.gov (United States)

    Henke, Matthias; Baumer, Julia; Blunk, Torsten; Tessmar, Joerg

    2014-03-01

    Radically cross-linked hydrogels are frequently used as cell carriers due to their excellent biocompatibility and their tissue-like mechanical properties. Through frequent investigation, PEG-based polymers such as oligo(poly(ethylene glycol)fumarate [OPF] have proven to be especially suitable as cell carriers by encapsulating cells during hydrogel formation. In some cases, NaCl or biodegradable gelatin microparticles were added prior to cross-linking in order to provide space for the proliferating cells, which would otherwise stay embedded in the hydrogel matrix. However, all of these immediate cross-linking procedures involve time consuming sample preparation and sterilization directly before cell culture and often show notable swelling after their preparation. In this study, ready to use OPF-hydrogel scaffolds were prepared by gas foaming, freeze drying, individual packing into bags and subsequent γ-sterilization. The scaffolds could be stored and used "off-the-shelf" without any need for further processing prior to cell culture. Thus the handling was simplified and the sterility of the cell carrier was assured. Further improvement of the gel system was achieved using a two component injectable system, which may be used for homogenous injection molding in order to create individually shaped three dimensional scaffolds. In order to evaluate the suitability of the scaffolds for tissue engineering, constructs were seeded with juvenile bovine chondrocytes and cultured for 28 days. Cross-sections of the respective constructs showed an intense and homogenous red staining of GAG with safranin O, indicating a homogenous cell distribution within the scaffolds and the production of substantial amounts of GAG-rich matrix. Copyright © 2012 John Wiley & Sons, Ltd.

  7. Methylcellulose Based Thermally Reversible Hydrogel System for Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Ram V. Devireddy

    2013-06-01

    Full Text Available The thermoresponsive behavior of a Methylcellulose (MC polymer was systematically investigated to determine its usability in constructing MC based hydrogel systems in cell sheet engineering applications. Solution-gel analyses were made to study the effects of polymer concentration, molecular weight and dissolved salts on the gelation of three commercially available MCs using differential scanning calorimeter and rheology. For investigation of the hydrogel stability and fluid uptake capacity, swelling and degradation experiments were performed with the hydrogel system exposed to cell culture solutions at incubation temperature for several days. From these experiments, the optimal composition of MC-water-salt that was able to produce stable hydrogels at or above 32 °C, was found to be 12% to 16% of MC (Mol. wt. of 15,000 in water with 0.5× PBS (~150mOsm. This stable hydrogel system was then evaluated for a week for its efficacy to support the adhesion and growth of specific cells in culture; in our case the stromal/stem cells derived from human adipose tissue derived stem cells (ASCs. The results indicated that the addition (evenly spread of ~200 µL of 2 mg/mL bovine collagen type -I (pH adjusted to 7.5 over the MC hydrogel surface at 37 °C is required to improve the ASC adhesion and proliferation. Upon confluence, a continuous monolayer ASC sheet was formed on the surface of the hydrogel system and an intact cell sheet with preserved cell–cell and cell–extracellular matrix was spontaneously and gradually detached when the grown cell sheet was removed from the incubator and exposed to room temperature (~30 °C within minutes.

  8. Methylcellulose based thermally reversible hydrogel system for tissue engineering applications.

    Science.gov (United States)

    Thirumala, Sreedhar; Gimble, Jeffrey M; Devireddy, Ram V

    2013-06-25

    The thermoresponsive behavior of a Methylcellulose (MC) polymer was systematically investigated to determine its usability in constructing MC based hydrogel systems in cell sheet engineering applications. Solution-gel analyses were made to study the effects of polymer concentration, molecular weight and dissolved salts on the gelation of three commercially available MCs using differential scanning calorimeter and rheology. For investigation of the hydrogel stability and fluid uptake capacity, swelling and degradation experiments were performed with the hydrogel system exposed to cell culture solutions at incubation temperature for several days. From these experiments, the optimal composition of MC-water-salt that was able to produce stable hydrogels at or above 32 °C, was found to be 12% to 16% of MC (Mol. wt. of 15,000) in water with 0.5× PBS (~150mOsm). This stable hydrogel system was then evaluated for a week for its efficacy to support the adhesion and growth of specific cells in culture; in our case the stromal/stem cells derived from human adipose tissue derived stem cells (ASCs). The results indicated that the addition (evenly spread) of ~200 µL of 2 mg/mL bovine collagen type -I (pH adjusted to 7.5) over the MC hydrogel surface at 37 °C is required to improve the ASC adhesion and proliferation. Upon confluence, a continuous monolayer ASC sheet was formed on the surface of the hydrogel system and an intact cell sheet with preserved cell-cell and cell-extracellular matrix was spontaneously and gradually detached when the grown cell sheet was removed from the incubator and exposed to room temperature (~30 °C) within minutes.

  9. Structural and behavioral characteristics of radiolytically synthesized polyacrylic acid–polyacrylonitrile copolymeric hydrogels

    International Nuclear Information System (INIS)

    Bera, Anuradha; Misra, R.K.; Singh, Shailendra K.

    2013-01-01

    Copolymeric hydrogels of polyacrylic acid (PAA) – polyacrylonitrile (PAN) was radiolytically synthesized from their respective monomers with trimethyloltrimethacrylate (TMPTMA) as the crosslinker wherein both polymerization and crosslinking could be achieved in a single step reaction using 60 Co γ-radiation under varying doses and dose rates. The formation of the hydrogels was confirmed by their FT-IR analysis, while their thermal degradation patterns were investigated through thermogravimetric analysis in both the dry and swelled state. The water sorption studies showed rapid swelling behavior of these hydrogels, where swelling (%EWC) was found to be strongly dependent on the ratio of the two monomers in the hydrogels and the swelling kinetics dependent on the dose rates of hydrogel synthesis. These radiolytically synthesized hydrogels responded to electrical stimulus both in terms of the bending speed as well as bending angle under an applied voltage. The nature of the deformation was reversible and can be controlled through switching the voltage on and off. - Highlights: • Polyacrylic acid – polyacrilonitrile copolymeric hydrogel has been radiolytically synthesized. • Trimethyloltrimethacrylate (TMPTMA) used as crosslinker. • Hydrogel has been characterized and tested for electroresponsive character. • Bending angles and bending speed were found dependent upon applied voltage

  10. Multiscale approach for the construction of equilibrated all-atom models of a poly(ethylene glycol)-based hydrogel

    Science.gov (United States)

    Li, Xianfeng; Murthy, N. Sanjeeva; Becker, Matthew L.; Latour, Robert A.

    2016-01-01

    A multiscale modeling approach is presented for the efficient construction of an equilibrated all-atom model of a cross-linked poly(ethylene glycol) (PEG)-based hydrogel using the all-atom polymer consistent force field (PCFF). The final equilibrated all-atom model was built with a systematic simulation toolset consisting of three consecutive parts: (1) building a global cross-linked PEG-chain network at experimentally determined cross-link density using an on-lattice Monte Carlo method based on the bond fluctuation model, (2) recovering the local molecular structure of the network by transitioning from the lattice model to an off-lattice coarse-grained (CG) model parameterized from PCFF, followed by equilibration using high performance molecular dynamics methods, and (3) recovering the atomistic structure of the network by reverse mapping from the equilibrated CG structure, hydrating the structure with explicitly represented water, followed by final equilibration using PCFF parameterization. The developed three-stage modeling approach has application to a wide range of other complex macromolecular hydrogel systems, including the integration of peptide, protein, and/or drug molecules as side-chains within the hydrogel network for the incorporation of bioactivity for tissue engineering, regenerative medicine, and drug delivery applications. PMID:27013229

  11. Ionic Conductivity of Polyelectrolyte Hydrogels.

    Science.gov (United States)

    Lee, Chen-Jung; Wu, Haiyan; Hu, Yang; Young, Megan; Wang, Huifeng; Lynch, Dylan; Xu, Fujian; Cong, Hongbo; Cheng, Gang

    2018-02-14

    Polyelectrolytes have many important functions in both living organisms and man-made applications. One key property of polyelectrolytes is the ionic conductivity due to their porous networks that allow the transport of water and small molecular solutes. Among polyelectrolytes, zwitterionic polymers have attracted huge attention for applications that involve ion transport in a polyelectrolyte matrix; however, it is still unclear how the functional groups of zwitterionic polymer side chains affect their ion transport and swelling properties. In this study, zwitterionic poly(carboxybetaine acrylamide), poly(2-methacryloyloxyethyl phosphorylcholine), and poly(sulfobetaine methacrylate) hydrogels were synthesized and their ionic conductivity was studied and compared to cationic, anionic, and nonionic hydrogels. The change of the ionic conductivity of zwitterionic and nonionic hydrogels in different saline solutions was investigated in detail. Zwitterionic hydrogels showed much higher ionic conductivity than that of the widely used nonionic poly(ethylene glycol) methyl ether methacrylate hydrogel in all tested solutions. For both cationic and anionic hydrogels, the presence of mobile counterions led to high ionic conductivity in low salt solutions; however, the ionic conductivity of zwitterionic hydrogels surpassed that of cationic and ionic hydrogels in high salt solutions. Cationic and anionic hydrogels showed much higher water content than that of zwitterionic hydrogels in deionized water; however, the cationic hydrogels shrank significantly with increasing saline concentration. This work provides insight into the effects of polyelectrolyte side chains on ion transport. This can guide us in choosing better polyelectrolytes for a broad spectrum of applications, including bioelectronics, neural implants, battery, and so on.

  12. Peritoneal adhesion prevention with a biodegradable and injectable N,O-carboxymethyl chitosan-aldehyde hyaluronic acid hydrogel in a rat repeated-injury model

    Science.gov (United States)

    Song, Linjiang; Li, Ling; He, Tao; Wang, Ning; Yang, Suleixin; Yang, Xi; Zeng, Yan; Zhang, Wenli; Yang, Li; Wu, Qinjie; Gong, Changyang

    2016-11-01

    Postoperative peritoneal adhesion is one of the serious issues because it induces severe clinical disorders. In this study, we prepared biodegradable and injectable hydrogel composed of N,O-carboxymethyl chitosan (NOCC) and aldehyde hyaluronic acid (AHA), and assessed its anti-adhesion effect in a rigorous and severe recurrent adhesion model which is closer to clinical conditions. The flexible hydrogel, which gelated in 66 seconds at 37 °C, was cross-linked by the schiff base derived from the amino groups of NOCC and aldehyde groups in AHA. In vitro cytotoxicity test showed the hydrogel was non-toxic. In vitro and in vivo degradation examinations demonstrated the biodegradable and biocompatibility properties of the hydrogel. The hydrogel discs could prevent the invasion of fibroblasts, whereas fibroblasts encapsulated in the porous 3-dimensional hydrogels could grow and proliferate well. Furthermore, the hydrogel was applied to evaluate the anti-adhesion efficacy in a more rigorous recurrent adhesion model. Compared with normal saline group and commercial hyaluronic acid (HA) hydrogel, the NOCC-AHA hydrogel exhibited significant reduction of peritoneal adhesion. Compared to control group, the blood and abdominal lavage level of tPA was increased in NOCC-AHA hydrogel group. These findings suggested that NOCC-AHA hydrogel had a great potential to serve as an anti-adhesion candidate.

  13. Core-shell silk hydrogels with spatially tuned conformations as drug-delivery system.

    Science.gov (United States)

    Yan, Le-Ping; Oliveira, Joaquim M; Oliveira, Ana L; Reis, Rui L

    2017-11-01

    Hydrogels of spatially controlled physicochemical properties are appealing platforms for tissue engineering and drug delivery. In this study, core-shell silk fibroin (SF) hydrogels of spatially controlled conformation were developed. The core-shell structure in the hydrogels was formed by means of soaking the preformed (enzymatically crosslinked) random coil SF hydrogels in methanol. When increasing the methanol treatment time from 1 to 10 min, the thickness of the shell layer can be tuned from about 200 to about 850 μm as measured in wet status. After lyophilization of the rehydrated core-shell hydrogels, the shell layer displayed compact morphology and the core layer presented porous structure, when observed by scanning electron microscopy. The conformation of the hydrogels was evaluated by Fourier transform infrared spectroscopy in wet status. The results revealed that the shell layer possessed dominant β-sheet conformation and the core layer maintained mainly random coil conformation. Enzymatic degradation data showed that the shell layers presented superior stability to the core layer. The mechanical analysis displayed that the compressive modulus of the core-shell hydrogels ranged from about 25 kPa to about 1.1 MPa by increasing the immersion time in methanol. When incorporated with albumin, the core-shell SF hydrogels demonstrated slower and more controllable release profiles compared with the non-treated hydrogel. These core-shell SF hydrogels of highly tuned properties are useful systems as drug-delivery system and may be applied as cartilage substitute. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Hydrogel nanoparticles in drug delivery.

    Science.gov (United States)

    Hamidi, Mehrdad; Azadi, Amir; Rafiei, Pedram

    2008-12-14

    Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system (e.g., hydrophilicity and extremely high water content) with a nanoparticle (e.g., very small size). Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based on both natural and synthetic polymers, each with its own advantages and drawbacks. Among the natural polymers, chitosan and alginate have been studied extensively for preparation of hydrogel nanoparticles and from synthetic group, hydrogel nanoparticles based on poly (vinyl alcohol), poly (ethylene oxide), poly (ethyleneimine), poly (vinyl pyrrolidone), and poly-N-isopropylacrylamide have been reported with different characteristics and features with respect to drug delivery. Regardless of the type of polymer used, the release mechanism of the loaded agent from hydrogel nanoparticles is complex, while resulting from three main vectors, i.e., drug diffusion, hydrogel matrix swelling, and chemical reactivity of the drug/matrix. Several crosslinking methods have been used in the way to form the hydrogel matix structures, which can be classified in two major groups of chemically- and physically-induced crosslinking.

  15. Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

    Science.gov (United States)

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2015-01-01

    Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91-93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability.

  16. Functionalization of oligo(poly(ethylene glycol)fumarate) hydrogels with finely dispersed calcium phosphate nanocrystals for bone-substituting purposes.

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Jansen, J.A.; Mikos, A.G.

    2007-01-01

    Biodegradable polymers that can be processed into injectable hydrogel matrices are promising candidates for bone-substituting purposes. Furthermore, by incorporating degradable calcium phosphate (CaP) particles and growth factors into these hydrogel matrices, a bone construct can be designed which

  17. Hydrogel Design for Supporting Neurite Outgrowth and Promoting Gene Delivery to Maximize Neurite Extension

    Science.gov (United States)

    Shepard, Jaclyn A.; Stevans, Alyson C.; Holland, Samantha; Wang, Christine E.; Shikanov, Ariella; Shea, Lonnie D.

    2012-01-01

    Hydrogels capable of gene delivery provide a combinatorial approach for nerve regeneration, with the hydrogel supporting neurite outgrowth and gene delivery inducing the expression of inductive factors. This report investigates the design of hydrogels that balance the requirements for supporting neurite growth with those requirements for promoting gene delivery. Enzymatically-degradable PEG hydrogels encapsulating dorsal root ganglia explants, fibroblasts, and lipoplexes encoding nerve growth factor were gelled within channels that can physically guide neurite outgrowth. Transfection of fibroblasts increased with increasing concentration of Arg-Gly-Asp (RGD) cell adhesion sites and decreasing PEG content. The neurite length increased with increasing RGD concentration within 10% PEG hydrogels, yet was maximal within 7.5% PEG hydrogels at intermediate RGD levels. Delivering lipoplexes within the gel produced longer neurites than culture in NGF-supplemented media or co-culture with cells exposed to DNA prior to encapsulation. Hydrogels designed to support neurite outgrowth and deliver gene therapy vectors locally may ultimately be employed to address multiple barriers that limit regeneration. PMID:22038654

  18. Drug-Loadable Calcium Alginate Hydrogel System for Use in Oral Bone Tissue Repair.

    Science.gov (United States)

    Chen, Luyuan; Shen, Renze; Komasa, Satoshi; Xue, Yanxiang; Jin, Bingyu; Hou, Yepo; Okazaki, Joji; Gao, Jie

    2017-05-06

    This study developed a drug-loadable hydrogel system with high plasticity and favorable biological properties to enhance oral bone tissue regeneration. Hydrogels of different calcium alginate concentrations were prepared. Their swelling ratio, degradation time, and bovine serum albumin (BSA) release rate were measured. Human periodontal ligament cells (hPDLCs) and bone marrow stromal cells (BMSCs) were cultured with both calcium alginate hydrogels and polylactic acid (PLA), and then we examined the proliferation of cells. Inflammatory-related factor gene expressions of hPDLCs and osteogenesis-related gene expressions of BMSCs were observed. Materials were implanted into the subcutaneous tissue of rabbits to determine the biosecurity properties of the materials. The materials were also implanted in mandibular bone defects and then scanned using micro-CT. The calcium alginate hydrogels caused less inflammation than the PLA. The number of mineralized nodules and the expression of osteoblast-related genes were significantly higher in the hydrogel group compared with the control group. When the materials were implanted in subcutaneous tissue, materials showed favorable biocompatibility. The calcium alginate hydrogels had superior osteoinductive bone ability to the PLA. The drug-loadable calcium alginate hydrogel system is a potential bone defect reparation material for clinical dental application.

  19. Biodegradation and Osteosarcoma Cell Cultivation on Poly(aspartic acid) Based Hydrogels.

    Science.gov (United States)

    Juriga, Dávid; Nagy, Krisztina; Jedlovszky-Hajdú, Angéla; Perczel-Kovách, Katalin; Chen, Yong Mei; Varga, Gábor; Zrínyi, Miklós

    2016-09-14

    Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.

  20. Preparation and properties of polyvinyl alcohol (PVA) and hydroxylapatite (HA) hydrogels for cartilage tissue engineering.

    Science.gov (United States)

    Yuan, F; Ma, M; Lu, L; Pan, Z; Zhou, W; Cai, J; Luo, S; Zeng, W; Yin, F

    2017-05-20

    A novel bioactive hydrogel for cartilage tissue based on polyvinyl alcohol (PVA) and hydroxylapatite (HA) were prepared, the effects of its component contents on the mechanical properties and microstructure of the hydrogel were investigated. The important properties of the scaffold composites, such as density, porosity, compressive modulus and microstructure were studied and analyzed through various measurements and methods. The biodegradability of hydrogel was evaluated by soaking the samples into artificial degradation solution at body temperature (36 - 37 oC) in vitro. Experimental results showed that the PVA/HA hydrogels had a density of 0.572 - 0.683 g/cm3, a porosity of 63.25 - 96.14% and a compressive modulus of 5.62 - 8.24 MP. The HA compound in the hydrogels enhanced the biodegradation significantly and linearly increased the rate of biodegradation by 2.3 - 8.5 %. The compressive modulus of PVA/HA exhibited a linear reduce to 0.86 - 1.53 MP with the time of degradation. The scaffold composites PVA/HA possess a high porosity, decent compressive modulus and good biodegradability. After further optimizing the structure and properties, this composite might be considered as novel hydrogel biomaterials to be applied in the field of cartilage tissue engineering.

  1. Genipin-cross-linked poly(L-lysine)-based hydrogels: synthesis, characterization, and drug encapsulation.

    Science.gov (United States)

    Wang, Steven S S; Hsieh, Ping-Lun; Chen, Pei-Shan; Chen, Yu-Tien; Jan, Jeng-Shiung

    2013-11-01

    Genipin-cross-linked hydrogels composed of biodegradable and pH-sensitive cationic poly(L-lysine) (PLL), poly(L-lysine)-block-poly(L-alanine) (PLL-b-PLAla), and poly(L-lysine)-block-polyglycine (PLL-b-PGly) polypeptides were synthesized, characterized, and used as carriers for drug delivery. These polypeptide hydrogels can respond to pH-stimulus and their gelling and mechanical properties, degradation rate, and drug release behavior can be tuned by varying polypeptide composition and cross-linking degree. Comparing with natural polymers, the synthetic polypeptides with well-defined chain length and composition can warrant the preparation of the hydrogels with tunable properties to meet the criteria for specific biomedical applications. These hydrogels composed of natural building blocks exhibited good cell compatibility and enzyme degradability and can support cell attachment/proliferation. The evaluation of these hydrogels for in vitro drug release revealed that the controlled release profile was a biphasic pattern with a mild burst release and a moderate release rate thereafter, suggesting the drug molecules were encapsulated inside the gel matrix. With the versatility of polymer chemistry and conjugation of functional moieties, it is expected these hydrogels can be useful for biomedical applications such as polymer therapeutics and tissue engineering. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Hypoxia-induced angiogenesis is increased by the controlled release of deferoxiamine from gelatin hydrogels.

    Science.gov (United States)

    Saito, Takashi; Tabata, Yasuhiko

    2014-08-01

    The objective of this study is to design biodegradable hydrogels for the controlled release of deferoxiamine (DFO) and evaluate their biological activity. When the DFO was added to human umbilical vein endothelial cells cultured in 5.0% O2, the level of hypoxia-inducible factor-1α and vascular endothelial growth factor significantly increased compared with that without DFO. The expression of angiogenesis-related genes was accordingly increased by the DFO addition. An aqueous solution of mixed gelatin and DFO was freeze-dried, and dehydrothermally treated at 140°C for 24h to prepare a gelatin hydrogel incorporating DFO. In the release test with phosphate-buffered saline solution (PBS) at 37°C, an initial DFO release of 60% was observed, followed by no release. When placed in PBS containing collagenase, the hydrogel was enzymatically degraded with time, and consequently released DFO in a degradation-dependent manner. After the hydrogel incorporating DFO was injected intramuscularly into a mouse model of hind limb ischemia, the number of new blood vessels formed was significantly higher than that with free DFO and DFO-free hydrogel. It is concluded that the DFO-containing hydrogel shows promising for inducing angiogenesis locally. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Eco-friendly PEG-based controlled release nano-formulations of Mancozeb: Synthesis and bioefficacy evaluation against phytopathogenic fungi Alternaria solani and Sclerotium rolfsii.

    Science.gov (United States)

    Majumder, Sujan; Shakil, Najam A; Kumar, Jitendra; Banerjee, Tirthankar; Sinha, Parimal; Singh, Braj B; Garg, Parul

    2016-12-01

    Controlled release (CR) nano-formulations of Mancozeb (manganese-zinc double salt of N,N-bisdithiocarbamic acid), a protective fungicide, have been prepared using laboratory-synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers without using any surfactants or external additives. The release kinetics of the developed Mancozeb CR formulations were studied and compared with that of commercially available 42% suspension concentrate and 75% wettable powder. Maximum amount of Mancozeb was released on 42nd day for PEG-600 and octyl chain, PEG-1000 and octyl chain, and PEG-600 and hexadecyl chain, on 35th day for PEG-1000 and hexadecyl chain, on 28th day for PEG-1500 and octyl chain, PEG-2000 and octyl chain, PEG-1500 and hexadecyl chain, and PEG-2000 and hexadecyl chain in comparison to both commercial formulations (15th day). The diffusion exponent (n value) of Mancozeb in water ranged from 0.42 to 0.62 in tested formulations. The half-release (t 1/2 ) values ranged from 17.35 to 35.14 days, and the period of optimum availability of Mancozeb ranged from 18.54 to 35.42 days. Further, the in vitro bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Alternaria solani and Sclerotium rolfsii by poison food technique. Effective dose for 50% inhibition in mgL -1 (ED 50 ) values of developed formulations varied from 1.31 to 2.79 mg L -1 for A. solani, and 1.60 to 3.14 mg L -1 for S. rolfsii. The present methodology is simple, economical, and eco-friendly for the development of environment-friendly CR formulations of Mancozeb. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, the maximum amount of active ingredient remains available for a reasonable period after application. In addition, the developed CR formulations were found to be suitable for fungicidal applications, allowing

  4. HYDROGELS AND THEIR APLICATION AREAS

    Directory of Open Access Journals (Sweden)

    AÇIKEL Safiye Meriç

    2016-05-01

    Full Text Available Hydrogels, being polymeric material,are named “Hydrophilic Polymer” because of their capable of holding large amounts of water in their three-dimensional networks. Hydrogels is not solved in water; however they have been swollen to their balace volume. Because of this swell behavior, they can adsorb big quantity of water in this structure. So they can term of “three sized polymers” due to protect their existing shape. Their cross linked bound structures are able to covalent or ionic and also one polymer which can for use of hydrogel polymer, must have hydrophilic groups such as carboxyl, carbonyl, amine and amide in main chains or side chains, and because of these groups water bound the polymer and polymer start to swell with rising volume and mass. Swell behavior of hydrogel is interested in quantity of hydrophilic groups. Hydrogels can use in different industrial and environmental areas with this high amount water holding capacity. They are used in food industry, biomedical, bioengineering, biotechnology, veterinary, pharmacist, agriculture, telecommunication, etc. Especially in current life, baby nappy has been including inside hydrogel beads. Also they used in contact lens, artificial cornea, synthetic cartilage and gullet, controlled medicine release, surgery yarns. This article general inform about usage area of hydrogels.

  5. Hydrogels with tunable stress relaxation regulate stem cell fate and activity

    Science.gov (United States)

    Chaudhuri, Ovijit; Gu, Luo; Klumpers, Darinka; Darnell, Max; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Lee, Hong-Pyo; Lippens, Evi; Duda, Georg N.; Mooney, David J.

    2016-03-01

    Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel's initial elastic modulus, degradation, and cell-adhesion-ligand density. We find that cell spreading, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) are all enhanced in cells cultured in gels with faster relaxation. Strikingly, MSCs form a mineralized, collagen-1-rich matrix similar to bone in rapidly relaxing hydrogels with an initial elastic modulus of 17 kPa. We also show that the effects of stress relaxation are mediated by adhesion-ligand binding, actomyosin contractility and mechanical clustering of adhesion ligands. Our findings highlight stress relaxation as a key characteristic of cell-ECM interactions and as an important design parameter of biomaterials for cell culture.

  6. Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

    International Nuclear Information System (INIS)

    Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

    2015-01-01

    Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91–93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability. - Highlights: • HA/CS/PAAc hydrogels were synthesized by gamma-ray irradiation. • HA/CS/PAAc hydrogels exhibited 91–93% gel fractions under 15 kGy radiation. • All of the HA/CS/PAAc hydrogels exhibited high water contents of over 90%. • The hydrogel samples showed relatively high cell viabilities of more than

  7. Photo-patterning of porous hydrogels for tissue engineering.

    Science.gov (United States)

    Bryant, Stephanie J; Cuy, Janet L; Hauch, Kip D; Ratner, Buddy D

    2007-07-01

    Since pore size and geometry strongly impact cell behavior and in vivo reaction, the ability to create scaffolds with a wide range of pore geometries that can be tailored to suit a particular cell type addresses a key need in tissue engineering. In this contribution, we describe a novel and simple technique to design porous, degradable poly(2-hydroxyethyl methacrylate) hydrogel scaffolds with well-defined architectures using a unique photolithography process and optimized polymer chemistry. A sphere-template was used to produce a highly uniform, monodisperse porous structure. To create a patterned and porous hydrogel scaffold, a photomask and initiating light were employed. Open, vertical channels ranging in size from 360+/-25 to 730+/-70 microm were patterned into approximately 700 microm thick hydrogels with pore diameters of 62+/-8 or 147+/-15 microm. Collagen type I was immobilized onto the scaffolds to facilitate cell adhesion. To assess the potential of these novel scaffolds for tissue engineering, a skeletal myoblast cell line (C2C12) was seeded onto scaffolds with 147 microm pores and 730 microm diameter channels, and analyzed by histology and digital volumetric imaging. Cell elongation, cell spreading and fibrillar formation were observed on these novel scaffolds. In summary, 3D architectures can be patterned into porous hydrogels in one step to create a wide range of tissue engineering scaffolds that may be tailored for specific applications.

  8. Regenerable Photovoltaic Devices with a Hydrogel-Embedded Microvascular Network

    Science.gov (United States)

    Koo, Hyung-Jun; Velev, Orlin D.

    2013-01-01

    Light-driven degradation of photoactive molecules could be one of the major obstacles to stable long term operation of organic dye-based solar light harvesting devices. One solution to this problem may be mimicking the regeneration functionality of a plant leaf. We report an organic dye photovoltaic system that has been endowed with such microfluidic regeneration functionality. A hydrogel medium with embedded channels allows rapid and uniform supply of photoactive reagents by a convection-diffusion mechanism. A washing-activation cycle enables reliable replacement of the organic component in a dye-sensitized photovoltaic system. Repetitive restoration of photovoltaic performance after intensive device degradation is demonstrated. PMID:23912814

  9. Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier

    International Nuclear Information System (INIS)

    Haryanto,; Singh, Deepti; Han, Sung Soo; Son, Jun Hyuk; Kim, Seong Cheol

    2015-01-01

    The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC–5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33 ± 6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03 ± 0.01%) and the highest tissue adherence (75.67 ± 1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®. - Highlights: • The crosslinked PEGDC/PEO hydrogel was developed by e-beam irradiation. • 10% PEGDC hydrogel film showed the highest elongation at break and tissue adhesion. • The COOH group enhanced the tissue adherence of hydrogel films on the intestine. • 10% PEGDC hydrogel film demonstrated a good anti-adhesive effect in animal study. • All of the hydrogel films with 10% PEGDC degraded in vivo within three weeks

  10. Preparation and properties of EDC/NHS mediated crosslinking poly (gamma-glutamic acid)/epsilon-polylysine hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Jiachuan [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Li, Zheng, E-mail: lizheng_nx@163.com [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Xia, Wen; Yang, Ning; Gong, Jixian [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Zhang, Jianfei, E-mail: zhangjianfei1960@126.com [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Qiao, Changsheng [Key Laboratory of Industrial Microbiology, Tianjin University of Science and Technology, Ministry of Education, Tianjin 300457 (China)

    2016-04-01

    In this paper, a novel pH-sensitive poly (amino acid) hydrogel based on poly γ-glutamic acid (γ-PGA) and ε-polylysine (ε-PL) was prepared by carbodiimide (EDC) and N-hydroxysuccinimide (NHS) mediated polymerization. The influence of PGA/PL molar ratio and EDC/NHS concentration on the structure and properties was studied. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved that hydrogels were crosslinked through amide bond linkage, and the conversion rate of a carboxyl group could reach 96%. Scanning electron microscopy (SEM) results showed a regularly porous structure with 20 μm pore size in average. The gelation time in the crosslink process of PGA/PL hydrogels was within less than 5 min. PGA/PL hydrogels had excellent optical performance that was evaluated by a novel optotype method. Furthermore, PGA/PL hydrogels were found to be pH-sensitive, which could be adjusted to the pH of swelling media intelligently. The terminal pH of swelling medium could be controlled at 5 ± 1 after equilibrium when the initial pH was within 3–11. The swelling kinetics was found to follow a Voigt model in deionized water but a pseudo-second-order model in normal saline and phosphate buffer solution, respectively. The differential swelling degrees were attributed to the swelling theory based on the different ratio of –COOH/–NH{sub 2} and pore size in hydrogels. The results of mechanical property indicated that PGA/PL hydrogels were soft and elastic. Moreover, PGA/PL hydrogels exhibited excellent biocompatibility by cell proliferation experiment. PGA/PL hydrogels could be degraded in PBS solution and the degradation rate was decreased with the increase of the molar ratio of PL. Considering the simple preparation process and pH-sensitive property, these PGA/PL hydrogels might have high potential for use in medical and clinical fields. - Highlights: • We prepared a biocompatible and degradable poly amino acids hydrogel via EDC

  11. Fluxgate magnetorelaxometry: a new approach to study the release properties of hydrogel cylinders and microspheres.

    Science.gov (United States)

    Wöhl-Bruhn, S; Heim, E; Schwoerer, A; Bertz, A; Harling, S; Menzel, H; Schilling, M; Ludwig, F; Bunjes, H

    2012-10-15

    Hydrogels are under investigation as long term delivery systems for biomacromolecules as active pharmaceutical ingredients. The release behavior of hydrogels can be tailored during the fabrication process. This study investigates the applicability of fluxgate magnetorelaxometry (MRX) as a tool to characterize the release properties of such long term drug delivery depots. MRX is based on the use of superparamagnetic core-shell nanoparticles as model substances. The feasibility of using superparamagnetic nanoparticles to study the degradation of and the associated release from hydrogel cylinders and hydrogel microspheres was a major point of interest. Gels prepared from two types of photo crosslinkable polymers based on modified hydroxyethylstarch, specifically hydroxyethyl starch-hydroxyethyl methacrylate (HES-HEMA) and hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)(6)MA), were analyzed. MRX analysis of the incorporated nanoparticles allowed to evaluate the influence of different crosslinking conditions during hydrogel production as well as to follow the increase in nanoparticle mobility as a result of hydrogel degradation during release studies. Conventional release studies with fluorescent markers (half-change method) were performed for comparison. MRX with superparamagnetic nanoparticles as model substances is a promising method to analyze pharmaceutically relevant processes such as the degradation of hydrogel drug carrier systems. In contrast to conventional release experiments MRX allows measurements in closed vials (reducing loss of sample and sampling errors), in opaque media and at low magnetic nanoparticle concentrations. Magnetic markers possess a better long-term stability than fluorescent ones and are thus also promising for the use in in vivo studies. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Injectable MMP-sensitive alginate hydrogels as hMSC delivery systems.

    Science.gov (United States)

    Fonseca, Keila B; Gomes, David B; Lee, Kangwon; Santos, Susana G; Sousa, Aureliana; Silva, Eduardo A; Mooney, David J; Granja, Pedro L; Barrias, Cristina C

    2014-01-13

    Hydrogels with the potential to provide minimally invasive cell delivery represent a powerful tool for tissue-regeneration therapies. In this context, entrapped cells should be able to escape the matrix becoming more available to actively participate in the healing process. Here, we analyzed the performance of proteolytically degradable alginate hydrogels as vehicles for human mesenchymal stem cells (hMSC) transplantation. Alginate was modified with the matrix metalloproteinase (MMP)-sensitive peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG), which did not promote dendritic cell maturation in vitro, neither free nor conjugated to alginate chains, indicating low immunogenicity. hMSC were entrapped within MMP-sensitive and MMP-insensitive alginate hydrogels, both containing cell-adhesion RGD peptides. Softer (2 wt % alginate) and stiffer (4 wt % alginate) matrices were tested. When embedded in a Matrigel layer, hMSC-laden MMP-sensitive alginate hydrogels promoted more extensive outward cell migration and invasion into the tissue mimic. In vivo, after 4 weeks of subcutaneous implantation in a xenograft mouse model, hMSC-laden MMP-sensitive alginate hydrogels showed higher degradation and host tissue invasion than their MMP-insensitive equivalents. In both cases, softer matrices degraded faster than stiffer ones. The transplanted hMSC were able to produce their own collagenous extracellular matrix, and were located not only inside the hydrogels, but also outside, integrated in the host tissue. In summary, injectable MMP-sensitive alginate hydrogels can act as localized depots of cells and confer protection to transplanted cells while facilitating tissue regeneration.

  13. Cytocompatible cellulose hydrogels containing trace lignin

    International Nuclear Information System (INIS)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-01-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm"2 and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  14. Cytocompatible cellulose hydrogels containing trace lignin

    Energy Technology Data Exchange (ETDEWEB)

    Nakasone, Kazuki; Kobayashi, Takaomi, E-mail: takaomi@nagaoakut.ac.jp

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12 h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43 N/mm{sup 2} and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference. - Highlights: • Cellulose hydrogel films with trace lignin were obtained from sugarcane bagasse. • Lignin content was found to be in the range of 1.62 − 0.68% by UV–Vis spectroscopy. • Higher lignin content strengthened mechanical properties of the hydrogel films. • Trace lignin affected the hydrogel morphology such as roughness and porosity. • High cell proliferation was observed in the hydrogel containing 1.68% lignin.

  15. Energy conversion in polyelectrolyte hydrogels

    Science.gov (United States)

    Olvera de La Cruz, Monica; Erbas, Aykut; Olvera de la Cruz Team

    Energy conversion and storage have been an active field of research in nanotechnology parallel to recent interests towards renewable energy. Polyelectrolyte (PE) hydrogels have attracted considerable attention in this field due to their mechanical flexibility and stimuli-responsive properties. Ideally, when a hydrogel is deformed, applied mechanical work can be converted into electrostatic, elastic and steric-interaction energies. In this talk, we discuss the results of our extensive molecular dynamics simulations of PE hydrogels. We demonstrate that, on deformation, hydrogels adjust their deformed state predominantly by altering electrostatic interactions between their charged groups rather than excluded-volume and bond energies. This is due to the hydrogel's inherent tendency to preserve electro-neutrality in its interior, in combination with correlations imposed by backbone charges. Our findings are valid for a wide range of compression ratios and ionic strengths. The electrostatic-energy alterations that we observe in our MD simulations may induce pH or redox-potential changes inside the hydrogels. The resulting energetic difference can be harvested, for instance, analogously to a Carnot engine, or facilitated for sensor applications. Center for Bio-inspired Energy Science (CBES).

  16. Microencapsulation of purple Brazilian cherry juice in xanthan, tara gums and xanthan-tara hydrogel matrixes.

    Science.gov (United States)

    Rutz, Josiane K; Zambiazi, Rui C; Borges, Caroline D; Krumreich, Fernanda D; da Luz, Suzane R; Hartwig, Naralice; da Rosa, Cleonice G

    2013-11-06

    The purple Brazilian cherry (Eugenia uniflora L.) juice was encapsulated in xanthan, tara and xanthan-tara hydrogel matrixes. Encapsulation efficiency, Differential Scanning Calorimetry (DSC), X-ray diffractometry, release profile, stability of carotenoids, phenolic compounds and antioxidant activity of microparticles were evaluated. Encapsulation was confirmed. The highest encapsulation efficiency was obtained with xanthan gum and hydrogel was mostly indicated for the release of carotenoids in GFS and IFS medium. Phenolic compounds had the highest release rate but not in a gradually way, regardless of wall material and fluids under analysis. Stored microparticles at 4 and 25 °C, showed carotenoid degradation. Xanthan and hydrogel wall material provided the greatest stability to these compounds. The microparticles' anti-oxidant activity decreased during storage due to the degradation of carotenoids. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Hydrogels in Miniemulsions

    Science.gov (United States)

    Landfester, Katharina; Musyanovych, Anna

    In the last decade, the synthesis of polymeric materials that respond to specific environment stimuli by changing their size has attracted widespread interest in both fundamental and applied areas of research. Hydrogels in dispersions are composed of randomly oriented, physically or chemically crosslinked hydrophilic or amphiphilic polymer chains. The synthesis of these gels at the nanoscale (nanogels or microgels) is especially of great importance for their application in drug delivery and controlled release systems, and in biomimetics, biosensing, tissue regeneration, heterogeneous catalysis, etc. The focus of this review is to present the versatility of the miniemulsion process for the formation of monodisperse nanogels from synthetic and natural polymers. Several applications of the obtained microgels are briefly described.

  18. Alginate-Collagen Fibril Composite Hydrogel

    Directory of Open Access Journals (Sweden)

    Mahmoud Baniasadi

    2015-02-01

    Full Text Available We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.

  19. Sustained Delivery of Chondroitinase ABC from Hydrogel System

    Directory of Open Access Journals (Sweden)

    Filippo Rossi

    2012-03-01

    Full Text Available In the injured spinal cord, chondroitin sulfate proteoglycans (CSPGs are the principal responsible of axon growth inhibition and they contribute to regenerative failure, promoting glial scar formation. Chondroitinase ABC (chABC is known for being able to digest proteoglycans, thus degrading glial scar and favoring axonal regrowth. However, its classic administration is invasive, infection-prone and clinically problematic. An agarose-carbomer (AC1 hydrogel, already used in SCI repair strategies, was here investigated as a delivery system capable of an effective chABC administration: the material ability to include chABC within its pores and the possibility to be injected into the target tissue were firstly proved. Subsequently, release kinetic and the maintenance of enzymatic activity were positively assessed: AC1 hydrogel was thus confirmed to be a feasible tool for chABC delivery and a promising device for spinal cord injury topic repair strategies.

  20. Synthesis and preparation of biodegradable hybrid dextran hydrogel incorporated with biodegradable curcumin nanomicelles for full thickness wound healing.

    Science.gov (United States)

    Alibolandi, Mona; Mohammadi, Marzieh; Taghdisi, Seyed Mohammad; Abnous, Khalil; Ramezani, Mohammad

    2017-10-30

    There is a clinical need for a novel, more efficient therapy for full thickness wound healing. In the current study, curcumin encapsulated PEG-PLA [poly(lactide)-block-poly(ethylene glycol)] nanomicelles were incorporated into dextran hydrogel for a full thickness dermal wound healing application. To assess the application of the hydrogel as a therapeutic wound dressing, its morphology, swelling pattern, kinetics of degradation, and capacity to control curcumin release were evaluated. It was found that the prepared hybrid hydrogel had acceptable biocompatibility, incorporation capacity of curcumin nanomicelles, and mechanical properties. An in vitro release experiment also demonstrated the sustained release of curcumin from dextran hydrogel, which was first controlled by the diffusion of curcumin from hydrogel and continued through hydrogel matrix erosion at the terminal phase. An in vivo wound healing experiment was carried out using dressing hydrogels on full thickness wounds in BALB/c mice. An histological study demonstrated that the application of curcumin nanomicelles incorporated hydrogel could significantly augment the re-epithelialization of epidermis and collagen deposition in the wound area. Expression of CD31 and vimentin in wound tissue was investigated using immunohistochemistry tests on the eighth day post wounding. The results obtained demonstrated that curcumin nanomicelles incorporated hydrogel could significantly accelerate angiogenesis, fibroblast accumulation, and the process of wound healing. Together, the data indicate that the prepared hybrid curcumin PEG-PLA nanomicelles incorporated dextran hydrogel is a promising candidate for full thickness wound treatment that increases re-epithelialization, collagen deposition, angiogenesis, and tissue granulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Novel Hydrogels from Renewable Resources

    Science.gov (United States)

    Karaaslan, Muzafer Ahmet

    2011-12-01

    The cell wall of most plant biomass from forest and agricultural resources consists of three major polymers, cellulose, hemicellulose and lignin. Of these, hemicelluloses have gained increasing attention as sustainable raw materials. In the first part of this study, novel pH-sensitive semi-IPN hydrogels based on hemicelluloses and chitosan were prepared using glutaraldehyde as the crosslinking agent. The hemicellulose isolated from aspen was analyzed for sugar content by HPLC, and its molecular weight distribution was determined by high performance size exclusion chromatography. Results revealed that hemicellulose had a broad molecular weight distribution with a fair amount of polymeric units, together with xylose, arabinose and glucose. The effect of hemicellulose content on mechanical properties and swelling behavior of hydrogels were investigated. The semi-IPNs hydrogel structure was confirmed by FT-IR, X-ray study and ninhydrin assay method. X-ray analysis showed that higher hemicellulose contents yielded higher crystallinity. Mechanical properties were mainly dependent on the crosslink density and average molecular weight between crosslinks. Swelling ratios increased with increasing hemicellulose content and were high at low pH values due to repulsion between similarly charged groups. In vitro release study of a model drug showed that these semi-IPN hydrogels could be used for controlled drug delivery into gastric fluid. The aim of the second part of this study was to control the crosslink density and the mechanical properties of hemicellulose/chitosan semi-IPN hydrogels by changing the crosslinking sequence. It has been hypothesized that by performing the crosslinking step before introducing hemicellulose, covalent crosslinking of chitosan would not be hindered and therefore more and/or shorter crosslinks could be formed. Furthermore, additional secondary interactions and crystalline domains introduced through hemicellulose could be favorable in terms of

  2. Injectable hydrogel as stem cell scaffolds from the thermosensitive terpolymer of NIPAAm/AAc/HEMAPCL

    Directory of Open Access Journals (Sweden)

    Lian S

    2012-09-01

    Full Text Available Sheng Lian,1Yan Xiao,1 Qingqing Bian,1Yu Xia,2 Changfa Guo,2 Shenguo Wang,2 Meidong Lang11Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, People's Republic of China; 2Department of Cardiac Surgery, Zhongshan Hospital, Fudan University and Shanghai Institute of Cardiovascular Diseases, Shanghai, People's Republic of ChinaAbstract: A series of biodegradable thermosensitive copolymers was synthesized by free radical polymerization with N-isopropylacrylamide (NIPAAm, acrylic acid (AAc and macromer 2-hydroxylethyl methacrylate-poly(ε-caprolactone (HEMAPCL. The structure and composition of the obtained terpolymers were confirmed by proton nuclear magnetic resonance spectroscopy, while their molecular weight was measured using gel permeation chromatography. The copolymers were dissolved in phosphate-buffered saline (PBS solution (pH = 7.4 with different concentrations to prepare hydrogels. The lower critical solution temperature (LCST, cloud point, and rheological property of the hydrogels were determined by differential scanning calorimetry, ultraviolet-visible spectrometry, and rotational rheometry, respectively. It was found that LCST of the hydrogel increased significantly with the increasing NIPAAm content, and hydrogel with higher AAc/HEMAPCL ratio exhibited better storage modulus, water content, and injectability. The hydrogels were formed by maintaining the copolymer solution at 37°C. The degradation experiment on the formed hydrogels was conducted in PBS solution for 2 weeks and demonstrated a less than 20% weight loss. Scanning electron microscopy was also used to study the morphology of the hydrogel. The copolymer with NIPAAm/AAc/HEMAPCL ratio of 88:9.6:2.4 was bioconjugated with type I collagen for the purpose of biocompatibility enhancement. In-vitro cytotoxicity

  3. Radiation processing of biodegradable polymer hydrogel from cellulose derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Wach, Radoslaw A.; Mitomo, Hiroshi [Gunma Univ., Faculty of Engineering, Department of Biological and Chemical Engineering, Kiryu, Gunma (Japan); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    The effects of high-energy radiation on ethers of cellulose: carboxymethyl-, hydroxypropyl- and hydroxyethylcellulose have been investigated. Polymers were irradiated in solid state and aqueous solution at various concentrations. Degree of substitution (DS), the concentration in the solution and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid and in diluted solution resulted in their degradation. A novel hydrogels of such natural polymers were synthesized, without using any additives, by irradiation at high concentration. It was found that high DS of CMC promoted crosslinking and, for all of the ethers, the gel formation occurred easier for more concentrated solutions. Paste-like form of the initial material, when water plasticised the bulk of polymer mass, along with the high dose rate and preventing oxygen accessibility to the sample during irradiation were favorable for hydrogel preparation. Up to 95% of gel fraction was obtained from 50 and 60% CMC solutions irradiated by gamma rays or by a beam of accelerated electrons (EB). The other polymers were more sensitive to the dose rate and formed gels with higher gel fraction while processed by EB. Moreover, polymers (except CMC) treated by gamma rays were susceptible to degradation after application of a dose over 50-100 kGy. The presence of oxygen in the system during irradiation limited a gel content and was prone to easier degradation of already formed gel. Produced hydrogels swelled markedly by absorption when paced in the solvent. Crosslinked polymers showed susceptibility to degradation by cellulase enzyme and by the action of microorganisms in compost or under natural conditions in soil thus could be included into the group of biodegradable materials. (author)

  4. Radiation processing of biodegradable polymer hydrogel from cellulose derivatives

    International Nuclear Information System (INIS)

    Wach, Radoslaw A.; Mitomo, Hiroshi; Yoshii, Fumio; Kume, Tamikazu

    2001-01-01

    The effects of high-energy radiation on ethers of cellulose: carboxymethyl-, hydroxypropyl- and hydroxyethylcellulose have been investigated. Polymers were irradiated in solid state and aqueous solution at various concentrations. Degree of substitution (DS), the concentration in the solution and irradiation conditions had a significant impact on the obtained products. Irradiation of polymers in solid and in diluted solution resulted in their degradation. A novel hydrogels of such natural polymers were synthesized, without using any additives, by irradiation at high concentration. It was found that high DS of CMC promoted crosslinking and, for all of the ethers, the gel formation occurred easier for more concentrated solutions. Paste-like form of the initial material, when water plasticised the bulk of polymer mass, along with the high dose rate and preventing oxygen accessibility to the sample during irradiation were favorable for hydrogel preparation. Up to 95% of gel fraction was obtained from 50 and 60% CMC solutions irradiated by gamma rays or by a beam of accelerated electrons (EB). The other polymers were more sensitive to the dose rate and formed gels with higher gel fraction while processed by EB. Moreover, polymers (except CMC) treated by gamma rays were susceptible to degradation after application of a dose over 50-100 kGy. The presence of oxygen in the system during irradiation limited a gel content and was prone to easier degradation of already formed gel. Produced hydrogels swelled markedly by absorption when paced in the solvent. Crosslinked polymers showed susceptibility to degradation by cellulase enzyme and by the action of microorganisms in compost or under natural conditions in soil thus could be included into the group of biodegradable materials. (author)

  5. Molecular imprinted hydrogel polymer (MIHP) as microbial immobilization media in artificial produced water treatment

    Science.gov (United States)

    Kardena, E.; Ridhati, S. L.; Helmy, Q.

    2018-01-01

    Produced water generated during oil and gas exploration and drilling, consists of many chemicals which used in drilling process. The production of produced water is over three fold of the oil production. The water-cut has increased over time and continues to do so because the fraction of oil in the reservoir decreases and it is more difficult to get the oil out from an old oil-field. It therefore requires more sea water to be injected in order to force the oil out; hence more produced water is generated. Produced water can pollute the environment if it is not treated properly. In this research, produced water will be treated biologically using bacterial consortium which is isolated from petroleum processing facility with Molecular Imprinted Hydrogel Polymer (MIHP) for microbial immobilization media. Microbial growth rate is determined by measuring the MLVSS and hydrogel mass, also by SEM-EDS analysis. SEM-EDS analysis is an analysis to evidence the presence of microbe trapped in hydrogel, and also to determine the types and weight of the molecules of hydrogel. From this research, suspended microbial growth rate was found at 0.1532/days and attached microbial growth rate was 0.3322/days. Furthermore, based on SEM analysis, microbe is entrapped inside the hydrogel. Effectiveness of microbial degradation activity was determined by measuring organic materials as COD. Based on COD measurement, degradation rate of organic materials in wastewater is 0.3089/days, with maximum COD removal efficiency of 76.67%.

  6. Nanohybrid hydrogels of laponite: PVA-Alginate as a potential wound healing material.

    Science.gov (United States)

    Golafshan, Nasim; Rezahasani, R; Tarkesh Esfahani, M; Kharaziha, M; Khorasani, S N

    2017-11-15

    The aim of this study was to develop a novel nanohybrid interpenetrating network hydrogel composed of laponite:polyvinyl alcohol (PVA)-alginate (LAP:PVA-Alginate) with adjustable mechanical, physical and biological properties for wound healing application. Results demonstrated that compared to PVA-Alginate, mechanical strength of LAP:PVA-Alginate significantly enhanced (upon 2 times). Moreover, incorporation of 2wt.% laponite reduced swelling ability (3 times) and degradation ratio (1.2 times) originating from effective enhancement of crosslinking density in the nanohybrid hydrogels. Furthermore, nanohybrid hydrogels revealed admirable biocompatibility against MG63 and fibroblast cells. Noticeably, MTT assay demonstrated that fibroblast proliferation significantly enhanced on 0.5wt.% LAP:PVA-alginate compared to PVA-alginate. Moreover, hemolysis and clotting tests indicated that the nanohybrid hydrogels promoted hemostasis which could be helpful in the wound dressing. Therefore, the synergistic effects of the nanohybrid hydrogels such as superior mechanical properties, adjustable degradation rate and admirable biocompatibility and hemolysis make them a desirable candidate for wound healing process. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Anisotropic dehydration of hydrogel surfaces.

    Science.gov (United States)

    Kaklamani, Georgia; Cheneler, David; Grover, Liam M; Adams, Michael J; Anastasiadis, Spiros H; Bowen, James

    2017-12-01

    Efforts to develop tissue-engineered skin for regenerative medicine have explored natural, synthetic, and hybrid hydrogels. The creation of a bilayer material, with the stratification exhibited by native skin, is a complex problem. The mechanically robust, waterproof epidermis presents the stratum corneum at the tissue/air interface, which confers many of these protective properties. In this work, we explore the effect of high temperatures on alginate hydrogels, which are widely employed for tissue engineering due to their excellent mechanical properties and cellular compatibility. In particular, we investigate the rapid dehydration of the hydrogel surface which occurs following local exposure to heated surfaces with temperatures in the range 100-200 °C. We report the creation of a mechanically strengthened hydrogel surface, with improved puncture resistance and increased coefficient of friction, compared to an unheated surface. The use of a mechanical restraint during heating promoted differences in the rate of mass loss; the rate of temperature increase within the hydrogel, in the presence and absence of restraint, is simulated and discussed. It is hoped that the results will be of use in the development of processes suitable for preparing skin-like analogues; application areas could include wound healing and skin restoration.

  8. The effect of glutathione as chain transfer agent in PNIPAAm-based thermo-responsive hydrogels for controlled release of proteins.

    Science.gov (United States)

    Drapala, Pawel W; Jiang, Bin; Chiu, Yu-Chieh; Mieler, William F; Brey, Eric M; Kang-Mieler, Jennifer J; Pérez-Luna, Victor H

    2014-03-01

    To control degradation and protein release using thermo-responsive hydrogels for localized delivery of anti-angiogenic proteins. Thermo-responsive hydrogels derived from N-isopropylacrylamide (NIPAAm) and crosslinked with poly(ethylene glycol)-co-(L-lactic acid) diacrylate (Acry-PLLA-b-PEG-b-PLLA-Acry) were synthesized via free radical polymerization in the presence of glutathione, a chain transfer agent (CTA) added to modulate their degradation and release properties. Immunoglobulin G (IgG) and the recombinant proteins Avastin® and Lucentis® were encapsulated in these hydrogels and their release was studied. The encapsulation efficiency of IgG was high (75-87%) and decreased with CTA concentration. The transition temperature of these hydrogels was below physiological temperature, which is important for minimally invasive therapies involving these materials. The toxicity from unreacted monomers and free radical initiators was eliminated with a minimum of three buffer extractions. Addition of CTA accelerated degradation and resulted in complete protein release. Glutathione caused the degradation products to become solubilized even at 37°C. Hydrogels prepared without glutathione did not disintegrate nor released protein completely after 3 weeks at 37°C. PEGylation of IgG postponed the burst release effect. Avastin® and Lucentis® released from degraded hydrogels retained their biological activity. These systems offer a promising platform for the localized delivery of proteins.

  9. MMP-sensitive PEG diacrylate hydrogels with spatial variations in matrix properties stimulate directional vascular sprout formation.

    Directory of Open Access Journals (Sweden)

    Michael V Turturro

    Full Text Available The spatial presentation of immobilized extracellular matrix (ECM cues and matrix mechanical properties play an important role in directed and guided cell behavior and neovascularization. The goal of this work was to explore whether gradients of elastic modulus, immobilized matrix metalloproteinase (MMP-sensitivity, and YRGDS cell adhesion ligands are capable of directing 3D vascular sprout formation in tissue engineered scaffolds. PEGDA hydrogels were engineered with mechanical and biofunctional gradients using perfusion-based frontal photopolymerization (PBFP. Bulk photopolymerized hydrogels with uniform mechanical properties, degradation, and immobilized biofunctionality served as controls. Gradient hydrogels exhibited an 80.4% decrease in elastic modulus and a 56.2% decrease in immobilized YRGDS. PBFP hydrogels also demonstrated gradients in hydrogel degradation with degradation times ranging from 10-12 hours in the more crosslinked regions to 4-6 hours in less crosslinked regions. An in vitro model of neovascularization, composed of co-culture aggregates of endothelial and smooth muscle cells, was used to evaluate the effect of these gradients on vascular sprout formation. Aggregate invasion in gradient hydrogels occurred bi-directionally with sprout alignment observed in the direction parallel to the gradient while control hydrogels with homogeneous properties resulted in uniform invasion. In PBFP gradient hydrogels, aggregate sprout length was found to be twice as long in the direction parallel to the gradient as compared to the perpendicular direction after three weeks in culture. This directionality was found to be more prominent in gradient regions of increased stiffness, crosslinked MMP-sensitive peptide presentation, and immobilized YRGDS concentration.

  10. pH-responsive self-healing injectable hydrogel based on N-carboxyethyl chitosan for hepatocellular carcinoma therapy.

    Science.gov (United States)

    Qu, Jin; Zhao, Xin; Ma, Peter X; Guo, Baolin

    2017-08-01

    Injectable hydrogels with pH-responsiveness and self-healing ability have great potential for anti-cancer drug delivery. Herein, we developed a series of polysaccharide-based self-healing hydrogels with pH-sensitivity as drug delivery vehicles for hepatocellular carcinoma therapy. The hydrogels were prepared by using N-carboxyethyl chitosan (CEC) synthesized via Michael reaction in aqueous solution and dibenzaldehyde-terminated poly(ethylene glycol) (PEGDA). Doxorubicin (Dox), as a model of water-soluble small molecule anti-cancer drug was encapsulated into the hydrogel in situ. Self-healing behavior of the hydrogels was investigated at microscopic and macroscopic levels, and the hydrogels showed rapid self-healing performance without any external stimulus owing to the dynamic covalent Schiff-base linkage between amine groups from CEC and benzaldehyde groups from PEGDA. The chemical structures, rheological property, in vitro gel degradation, morphology, gelation time and in vitro Dox release behavior from the hydrogels were characterized. Injectability was verified by in vitro injection and in vivo subcutaneous injection in a rat. pH-responsive behavior was verified by in vitro Dox release from hydrogels in PBS solutions with different pH values. Furthermore, the activity of Dox released from hydrogel matrix was evaluated by employing human hepatocellular liver carcinoma (HepG2). Cytotoxicity test of the hydrogels using L929 cells confirmed their good cytocompatibility. Together, these pH-responsive self-healing injectable hydrogels are excellent candidates as drug delivery vehicles for liver cancer treatment. STATEMENT OF SIGNIFICANCE: pH-responsive drug delivery system could release drug efficiently in targeted acid environment and minimalize the amount of drug release in normal physiological environment. pH-sensitive injectable hydrogels as smart anti-cancer drug delivery carriers show great potential application for cancer therapy. The hydrogels with self

  11. Development of polymer-polysaccharide hydrogels for controlling drug delivery

    Science.gov (United States)

    Baldwin, Aaron David

    The use of polymers as biomaterials has evolved over the past several decades, encompassing an expanding synthetic toolbox and many bio-mimetic approaches. Both synthetic and natural polymers have been used as components for biomaterials as their unique chemical structures can provide specific functions for desired applications. Of these materials, heparin, a highly sulfated naturally occurring polysaccharide, has been investigated extensively as a core component in drug delivery platforms and tissue engineering. The goal of this work was to further explore the use of heparin via conjugation with synthetic polymers for applications in drug delivery. We begin by investigating low molecular weight heparin (LMWH), a depolymerized heparin that is used medicinally in the prevention of thrombosis by subcutaneous injection or intravenous drip. Certain disease states or disorders require frequent administration with invasive delivery modalities leading to compliance issues for individuals on prolonged therapeutic courses. To address these issues, a long-term delivery method was developed for LMWH via subcutaneous injection of in situ hydrogelators. This therapy was accomplished by chemical modification of LMWH with maleimide functionality so that it may be crosslinked into continuous hydrogel networks with four-arm thiolated polyethylene glycol (PEG-SH). These hydrogels degrade via hydrolysis over a period of weeks and release bioactive LMWH with first-order kinetics as determined by in vitro and in vivo models, thus indicating the possibility of an alternative means of heparin delivery over current accepted methodologies. Evaluation of the maleimide-thiol chemistries applied in the LMWH hydrogels revealed reversibility for some conjugates under reducing conditions. Addition chemistries, such as maleimide-thiol reactions, are widely employed in biological conjugates and are generally accepted as stable. Here we show that the resulting succinimide thioether formed by the

  12. Angiogenic competency of biodegradable hydrogels fabricated from polyethylene glycol-crosslinked tyrosine-derived polycarbonates

    Directory of Open Access Journals (Sweden)

    HJ Sung

    2008-04-01

    Full Text Available Synthetic biomaterials can be used as instructive biological milieus to guide cellular behaviour and function. To further realize this application, we synthesized a series of structurally similar hydrogels and tested their ability to modulate angiogenesis. Hydrogels were synthesized from poly(DTE-co-x% DT carbonate crosslinked by y% poly(ethylene glycol (PEG. Hydrogel desaminotyrosyl tyrosine (DT contents (x% ranged from 10-100%, and crosslink densities (y% PEG-crosslinker ranged from 5-80%. The hydrogels were fashioned into porous scaffolds with highly interconnected macro- and micro-pore (>100 and <10 mm in diameter, respectively architecture using poly(DTE-co-10%DT carbonate crosslinked with 8% PEG. Under physiological conditions (in vitro, the hydrogels degraded into three major products: desaminotyrosyl-tyrosine ethyl ester (DTE, desaminotyrosyl tyrosine (DT, and poly(ethylene glycol-di-DT-hydrazide (PEG-di-DT hydrazide. Increasing either DT content or crosslink density brought quickened degradation. Because DT and DTE, two of the three major degradation products, have not demonstrated any noticeable cytotoxicity or angiogenic effect in previous studies, we measured the cytotoxicity of PEG-di-DT hydrazide, the third major degradation product. We found that PEG-di-DT hydrazide only displayed significant cytotoxicity at the high concentration of 100 mg/mL. Interestingly, PEG-di-DT hydrazide and its further degradation product PEG-dihydrazide stimulated in vitro endothelial cell migration and tubulogenesis, which is comparable to results found with FGF-beta treatment. Subcutaneous implantation of the PEG-crosslinked poly(DTE-co-10%DT carbonate scaffolds into the backs of rats elicited greater tissue growth over time and superior vascularization than poly(DTE carbonate implantation. These results show that this new class of biomaterials has a strong potential to modulate angiogenesis.

  13. Electrochemical characterization of hydrogels for biomimetic applications

    DEFF Research Database (Denmark)

    Peláez, L.; Romero, V.; Escalera, S.

    2011-01-01

    ) or a photoinitiator (P) to encapsulate and stabilize biomimetic membranes for novel separation technologies or biosensor applications. In this paper, we have investigated the electrochemical properties of the hydrogels used for membrane encapsulation. Specifically, we studied the crosslinked hydrogels by using...... electrochemical impedance spectroscopy (EIS), and we demonstrated that chemically crosslinked hydrogels had lower values for the effective electrical resistance and higher values for the electrical capacitance compared with hydrogels with photoinitiated crosslinking. Transport numbers were obtained using......〉 and 〈Pw〉 values than PEG‐1000‐DMA‐P and PEG‐400‐DA‐P hydrogels. In conclusion, our results show that hydrogel electrochemical properties can be controlled by the choice of polymer and type of crosslinking used and that their water and salt permeability properties are congruent with the use of hydrogels...

  14. [Thromboresistance of glucose-containing hydrogels].

    Science.gov (United States)

    Valuev, I L; Valuev, L I; Vanchugova, L V; Obydennova, I V; Valueva, T A

    2013-01-01

    The thromboresistance of glucose-sensitive polymer hydrogels, modeling one of the functions of the pancreas, namely, the ability to secrete insulin in response to the introduction of glucose into the environment, has been studied. Hydrogels were synthesized by the copolymerization of hydroxyethyl methacrylate with N-acryloyl glucosamine in the presence of a cross-linking agent and subsequently treated with concanavalin A. Introduction of glucose residues into the hydrogel did not result in significant changes in either the number of trombocytes adhered to the hydrogel or the degree of denaturation of blood plasma proteins interacting with the hydrogel. Consequently, the biological activity of insulin did not change after release from the hydrogel. The use of glucose-sensitive hydrogels is supposed to contribute to the development of a novel strategy for the treatment of diabetes.

  15. Hydrogels and their medical applications

    Science.gov (United States)

    Rosiak, Janusz M.; Yoshii, Fumio

    1999-05-01

    Biomaterials play a key role in most approaches for engineering tissues as substitutes for functional replacement, for components of devices related to therapy and diagnosis, for drug delivery systems and supportive scaffolds for guided tissue growth. Modern biomaterials could be composed of various components, e.g. metals, ceramics, natural tissues, polymers. In this last group, the hydrogels, hydrophilic polymeric gels with requested biocompatibility and designed interaction with living surrounding seem to be one of the most promising group of biomaterials. Especially, if they are formed by means of ionizing radiation. In early 1950s, the pioneers of the radiation chemistry of polymers began some experiments with radiation crosslinking of hydrophilic polymers. However, hydrogels were analyzed mainly from the point of view of the phenomenon associated with radiation synthesis, with topology of network and relation between radiation parameters of the processes. Fundamental monographs on radiation polymer physics and chemistry written by A. Charlesby (Atomic Radition and polymers, Pergamon Press, Oxford, 1960) and A. Chapiro (Radiation Chemistry of Polymeric Systems, Interscience, New York, 1962) proceed from this time. The noticeable interest in the application of radiation techniques to obtain hydrogels for biomedical purposes began in the late sixties as a result of the papers and patents invented by Japanese and American scientists, headed by Kaetsu in Japan and Hoffman in USA. Immobilization of biologically active species in hydrogel matrices, their use as drug delivery systems and enzyme traps as well as the modification of material surfaces to improve biocompatibility and their ability to bond antigens and antibodies had been the main subjects of these investigations. In this article a brief summary of investigations on mechanism and kinetics of radiation formation of hydrogels as well as some examples of commercialized hydrogel biomaterials have been

  16. Hydrogels and their medical applications

    International Nuclear Information System (INIS)

    Rosiak, Janusz M.; Yoshii, Fumio

    1999-01-01

    Biomaterials play a key role in most approaches for engineering tissues as substitutes for functional replacement, for components of devices related to therapy and diagnosis, for drug delivery systems and supportive scaffolds for guided tissue growth. Modern biomaterials could be composed of various components, e.g. metals, ceramics, natural tissues, polymers. In this last group, the hydrogels, hydrophilic polymeric gels with requested biocompatibility and designed interaction with living surrounding seem to be one of the most promising group of biomaterials. Especially, if they are formed by means of ionizing radiation. In early 1950s, the pioneers of the radiation chemistry of polymers began some experiments with radiation crosslinking of hydrophilic polymers. However, hydrogels were analyzed mainly from the point of view of the phenomenon associated with radiation synthesis, with topology of network and relation between radiation parameters of the processes. Fundamental monographs on radiation polymer physics and chemistry written by A. Charlesby (Atomic Radition and polymers, Pergamon Press, Oxford, 1960) and A. Chapiro (Radiation Chemistry of Polymeric Systems, Interscience, New York, 1962) proceed from this time. The noticeable interest in the application of radiation techniques to obtain hydrogels for biomedical purposes began in the late sixties as a result of the papers and patents invented by Japanese and American scientists, headed by Kaetsu in Japan and Hoffman in USA. Immobilization of biologically active species in hydrogel matrices, their use as drug delivery systems and enzyme traps as well as the modification of material surfaces to improve biocompatibility and their ability to bond antigens and antibodies had been the main subjects of these investigations. In this article a brief summary of investigations on mechanism and kinetics of radiation formation of hydrogels as well as some examples of commercialized hydrogel biomaterials have been

  17. Short-peptide-based molecular hydrogels: novel gelation strategies and applications for tissue engineering and drug delivery

    Science.gov (United States)

    Wang, Huaimin; Yang, Zhimou

    2012-08-01

    Molecular hydrogels hold big potential for tissue engineering and controlled drug delivery. Our lab focuses on short-peptide-based molecular hydrogels formed by biocompatible methods and their applications in tissue engineering (especially, 3D cell culture) and controlled drug delivery. This feature article firstly describes our recent progresses of the development of novel methods to form hydrogels, including the strategy of disulfide bond reduction and assistance with specific protein-peptide interactions. We then introduce the applications of our hydrogels in fields of controlled stem cell differentiation, cell culture, surface modifications of polyester materials by molecular self-assembly, and anti-degradation of recombinant complex proteins. A novel molecular hydrogel system of hydrophobic compounds that are only formed by hydrolysis processes was also included in this article. The hydrogels of hydrophobic compounds, especially those of hydrophobic therapeutic agents, may be developed into a carrier-free delivery system for long term delivery of therapeutic agents. With the efforts in this field, we believe that molecular hydrogels formed by short peptides and hydrophobic therapeutic agents can be practically applied for 3D cell culture and long term drug delivery in near future, respectively.

  18. Cytocompatible in situ forming chitosan/hyaluronan hydrogels via a metal-free click chemistry for soft tissue engineering.

    Science.gov (United States)

    Fan, Ming; Ma, Ye; Mao, Jiahui; Zhang, Ziwei; Tan, Huaping

    2015-07-01

    Injectable hydrogels are important cell scaffolding materials for tissue engineering and regenerative medicine. Here, we report a new class of biocompatible and biodegradable polysaccharide hydrogels derived from chitosan and hyaluronan via a metal-free click chemistry, without the addition of copper catalyst. For the metal-free click reaction, chitosan and hyaluronan were modified with oxanorbornadiene (OB) and 11-azido-3,6,9-trioxaundecan-1-amine (AA), respectively. The gelation is attributed to the triazole ring formation between OB and azido groups of polysaccharide derivatives. The molecular structures were verified by FT-IR spectroscopy and elemental analysis, giving substitution degrees of 58% and 47% for chitosan-OB and hyaluronan-AA, respectively. The in vitro gelation, morphologies, equilibrium swelling, compressive modulus and degradation of the composite hydrogels were examined. The potential of the metal-free hydrogel as a cell scaffold was demonstrated by encapsulation of human adipose-derived stem cells (ASCs) within the gel matrix in vitro. Cell culture showed that this metal-free hydrogel could support survival and proliferation of ASCs. A preliminary in vivo study demonstrated the usefulness of the hydrogel as an injectable scaffold for adipose tissue engineering. These characteristics provide a potential opportunity to use the metal-free click chemistry in preparation of biocompatible hydrogels for soft tissue engineering applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Self-degradation of tissue adhesive based on oxidized dextran and poly-L-lysine.

    Science.gov (United States)

    Matsumura, Kazuaki; Nakajima, Naoki; Sugai, Hajime; Hyon, Suong-Hyu

    2014-11-26

    We have developed a low-toxicity bioadhesive based on oxidized dextran and poly-L-lysine. Here, we report that the mechanical properties and degradation of this novel hydrogel bioadhesive can be controlled by changing the extent of oxidation of the dextran and the type or concentration of the anhydride species in the acylated poly-L-lysine. The dynamic moduli of the hydrogels can be controlled from 120 Pa to 20 kPa, suggesting that they would have mechanical compatibility with various tissues, and could have applications as tissue adhesives. Development of the hydrogel color from clear to brown indicates that the reaction between the dextran aldehyde groups and the poly-L-lysine amino groups may be induced by a Maillard reaction via Schiff base formation. Degradation of the aldehyde dextran may begin by reaction of the amino groups in the poly-L-lysine. The gel degradation can be ascribed to degradation of the aldehyde dextran in the hydrogel, although the aldehyde dextran itself is relatively stable in water. The oxidized dextran and poly-L-lysine, and the degraded hydrogel showed low cytotoxicities. These findings indicate that a hydrogel consisting of oxidized dextran and poly-L-lysine has low toxicity and a well-controlled degradation rate, and has potential clinical applications as a bioadhesive. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Alginate hydrogel as a promising scaffold for dental-derived stem cells: an in vitro study.

    Science.gov (United States)

    Moshaverinia, Alireza; Chen, Chider; Akiyama, Kentaro; Ansari, Sahar; Xu, Xingtian; Chee, Winston W; Schricker, Scott R; Shi, Songtao

    2012-12-01

    The objectives of this study were to: (1) develop an injectable and biodegradable scaffold based on oxidized alginate microbeads encapsulating periodontal ligament (PDLSCs) and gingival mesenchymal stem cells (GMSCs); and (2) investigate the stem cell viability, and osteogenic differentiation of the stem cells in vitro. Stem cells were encapsulated using alginate hydrogel. The stem cell viability, proliferation and differentiation to adipogenic and osteogenic tissues were studied. To investigate the expression of both adipogenesis and ontogenesis related genes, the RNA was extracted and RT-PCR was performed. The degradation behavior of hydrogel based on oxidized sodium alginate with different degrees of oxidation was studied in PBS at 37 °C as a function of time by monitoring the changes in weight loss. The swelling kinetics of alginate hydrogel was also investigated. The results showed that alginate is a promising candidate as a non-toxic scaffold for PDLSCs and GMSCs. It also has the ability to direct the differentiation of these stem cells to osteogenic and adipogenic tissues as compared to the control group in vitro. The encapsulated stem cells remained viable in vitro and both osteo-differentiated and adipo-differentiated after 4 weeks of culturing in the induction media. It was found that the degradation profile and swelling kinetics of alginate hydrogel strongly depends on the degree of oxidation showing its tunable chemistry and degradation rate. These findings demonstrate for the first time that immobilization of PDLSCs and GMSCs in the alginate microspheres provides a promising strategy for bone tissue engineering.

  1. Maintenance of neural progenitor cell stemness in 3D hydrogels requires matrix remodelling

    Science.gov (United States)

    Madl, Christopher M.; Lesavage, Bauer L.; Dewi, Ruby E.; Dinh, Cong B.; Stowers, Ryan S.; Khariton, Margarita; Lampe, Kyle J.; Nguyen, Duong; Chaudhuri, Ovijit; Enejder, Annika; Heilshorn, Sarah C.

    2017-12-01

    Neural progenitor cell (NPC) culture within three-dimensional (3D) hydrogels is an attractive strategy for expanding a therapeutically relevant number of stem cells. However, relatively little is known about how 3D material properties such as stiffness and degradability affect the maintenance of NPC stemness in the absence of differentiation factors. Over a physiologically relevant range of stiffness from ~0.5 to 50 kPa, stemness maintenance did not correlate with initial hydrogel stiffness. In contrast, hydrogel degradation was both correlated with, and necessary for, maintenance of NPC stemness. This requirement for degradation was independent of cytoskeletal tension generation and presentation of engineered adhesive ligands, instead relying on matrix remodelling to facilitate cadherin-mediated cell-cell contact and promote β-catenin signalling. In two additional hydrogel systems, permitting NPC-mediated matrix remodelling proved to be a generalizable strategy for stemness maintenance in 3D. Our findings have identified matrix remodelling, in the absence of cytoskeletal tension generation, as a previously unknown strategy to maintain stemness in 3D.

  2. Photocrosslinkable Gelatin/Tropoelastin Hydrogel Adhesives for Peripheral Nerve Repair.

    Science.gov (United States)

    Soucy, Jonathan R; Shirzaei Sani, Ehsan; Portillo Lara, Roberto; Diaz, David; Dias, Felipe; Weiss, Anthony S; Koppes, Abigail N; Koppes, Ryan A; Annabi, Nasim

    2018-05-09

    Suturing peripheral nerve transections is the predominant therapeutic strategy for nerve repair. However, the use of sutures leads to scar tissue formation, hinders nerve regeneration, and prevents functional recovery. Fibrin-based adhesives have been widely used for nerve reconstruction, but their limited adhesive and mechanical strength and inability to promote nerve regeneration hamper their utility as a stand-alone intervention. To overcome these challenges, we engineered composite hydrogels that are neurosupportive and possess strong tissue adhesion. These composites were synthesized by photocrosslinking two naturally derived polymers, gelatin-methacryloyl (GelMA) and methacryloyl-substituted tropoelastin (MeTro). The engineered materials exhibited tunable mechanical properties by varying the GelMA/MeTro ratio. In addition, GelMA/MeTro hydrogels exhibited 15-fold higher adhesive strength to nerve tissue ex vivo compared to fibrin control. Furthermore, the composites were shown to support Schwann cell (SC) viability and proliferation, as well as neurite extension and glial cell participation in vitro, which are essential cellular components for nerve regeneration. Finally, subcutaneously implanted GelMA/MeTro hydrogels exhibited slower degradation in vivo compared with pure GelMA, indicating its potential to support the growth of slowly regenerating nerves. Thus, GelMA/MeTro composites may be used as clinically relevant biomaterials to regenerate nerves and reduce the need for microsurgical suturing during nerve reconstruction.

  3. Fabrication of keratin-silica hydrogel for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kakkar, Prachi; Madhan, Balaraman, E-mail: bmadhan76@yahoo.co.in

    2016-09-01

    In the recent past, keratin has been fabricated into different forms of biomaterials like scaffold, gel, sponge, film etc. In lieu of the myriad advantages of the hydrogels for biomedical applications, a keratin-silica hydrogel was fabricated using tetraethyl orthosilicate (TEOS). Textural analysis shed light on the physical properties of the fabricated hydrogel, inturn enabling the optimization of the hydrogel. The optimized keratin-silica hydrogel was found to exhibit instant springiness, optimum hardness, with ease of spreadability. Moreover, the hydrogel showed excellent swelling with highly porous microarchitecture. MTT assay and DAPI staining revealed that keratin-silica hydrogel was biocompatible with fibroblast cells. Collectively, these properties make the fabricated keratin-silica hydrogel, a suitable dressing material for biomedical applications. - Highlights: • Keratin-silica hydrogel has been fabricated using sol–gel technique. • The hydrogel shows appropriate textural properties. • The hydrogel promotes fibroblast cells proliferation. • The hydrogel has potential soft tissue engineering applications like wound healing.

  4. Novel thermosensitive hydrogel for preventing formation of abdominal adhesions

    Directory of Open Access Journals (Sweden)

    Gao X

    2013-07-01

    Full Text Available Xiang Gao,1,2 Xiaohui Deng,3 Xiawei Wei,2 Huashan Shi,2 Fengtian Wang,2 Tinghong Ye,2 Bin Shao,2 Wen Nie,2 Yuli Li,2 Min Luo,2 Changyang Gong,2 Ning Huang1 1Department of Pathophysiology, College of Preclinical and Forensic Medical Sciences, Sichuan University, Chengdu, 2State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, 3Department of Human Anatomy, Xinxiang Medical University, Xinxiang, People’s Republic of China Abstract: Adhesions can form after almost any type of abdominal surgery. Postoperative adhesions can be prevented by improved surgical techniques, such as reducing surgical trauma, preventing ischemia, and avoiding exposure of the peritoneal cavity to foreign materials. Although improved surgical techniques can potentially reduce formation of adhesions, they cannot be eliminated completely. Therefore, finding more effective methods to prevent postoperative adhesions is imperative. Recently, we found that a novel thermosensitive hydrogel, ie, poly(ε-caprolactone-poly(ethylene glycol-poly(ε-caprolactone (PCEC had the potential to prevent postoperative adhesions. Using the ring-opening polymerization method, we prepared a PCEC copolymer which could be dissolved and assembled at 55°C into PCEC micelles with mean size of 25 nm. At body temperature, a solution containing PCEC micelles could convert into a hydrogel. The PCEC copolymer was biodegradable and had low toxicity in vitro and in vivo. We found that most animals in a hydrogel-treated group (n = 10 did not develop adhesions. In contrast, 10 untreated animals developed adhesions that could only be separated by sharp dissection (P < 0.001. The hydrogel could adhere to peritoneal wounds and degraded gradually over 7–9 days, transforming into a viscous fluid that was completely absorbed within 12 days. The injured parietal and visceral peritoneum remesothelialized over about seven and nine days

  5. Polyvinyl alcohol hydrogels for iontohporesis

    Science.gov (United States)

    Bera, Prasanta; Alam, Asif Ali; Arora, Neha; Tibarewala, Dewaki Nandan; Basak, Piyali

    2013-06-01

    Transdermal therapeutic systems propound controlled release of active ingredients through the skin into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. The iontophoresis deal with the systemic delivery of the bioactive agents (drug) by applying an electric current. It is basically an injection without the needle. The iontophoretic system requires a gel-based matrix to accommodate the bioactive agent. Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability. In this work we have prepared polyvinyl alcohol (PVA) hydrogel. We have cross linked polyvinyl alcohol chemically with Glutaraldehyde with different wt%. FTIR study reveals the chemical changes during cross linking. Swelling in water, is done to have an idea about drug loading and drug release from the membrane. After drug loading to the hydrogels, we have studied the drug release property of the hydrogels using salicylic acid as a model drug.

  6. Synthesis and characterization of polymeric hydrogel containing caffeine for cosmeceutical applications

    International Nuclear Information System (INIS)

    Santos, Tiago C.; Oliveira, Maria José A.; Lugão, Ademar B.

    2017-01-01

    Caffeine, a substance with belongs to the group of methylxanthines, is alkaloids that penetrate in the human epidermis but is not easily absorbed into the bloodstream. With a dermatological active substance, it exerts action on the subcutaneous adipose tissue causing adipocyte lipolysis through the inhibition of phosphodiesterase. Based on these considerations, the objective of this study was to investigate the behavior of caffeine in a polymeric hydrogel matrix, for possible cosmeceutical applications. The hydrogels were cross-linked and sterilized by Cobalt-60 source gamma irradiation. In the characterization, were used thermogravimetry (TGA), scanning electron microscopy (SEM), differential scanning calorimetry (DSC). It was possible to observe by SEM the presence of crystals in the hydrogel sample. The DSC experiment confirmed a crystallinity of the sample and that caffeine is not degraded by gamma irradiation at 25 kGy. The results were satisfactory, allowing a new investigations that certify the benefits of its application. (author)

  7. Synthesis and characterization of polymeric hydrogel containing caffeine for cosmeceutical applications

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Tiago C.; Oliveira, Maria José A.; Lugão, Ademar B., E-mail: tiagocesar-13@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNE-SP), Sao Paulo, SP (Brazil)

    2017-07-01

    Caffeine, a substance with belongs to the group of methylxanthines, is alkaloids that penetrate in the human epidermis but is not easily absorbed into the bloodstream. With a dermatological active substance, it exerts action on the subcutaneous adipose tissue causing adipocyte lipolysis through the inhibition of phosphodiesterase. Based on these considerations, the objective of this study was to investigate the behavior of caffeine in a polymeric hydrogel matrix, for possible cosmeceutical applications. The hydrogels were cross-linked and sterilized by Cobalt-60 source gamma irradiation. In the characterization, were used thermogravimetry (TGA), scanning electron microscopy (SEM), differential scanning calorimetry (DSC). It was possible to observe by SEM the presence of crystals in the hydrogel sample. The DSC experiment confirmed a crystallinity of the sample and that caffeine is not degraded by gamma irradiation at 25 kGy. The results were satisfactory, allowing a new investigations that certify the benefits of its application. (author)

  8. Photoreversible Covalent Hydrogels for Soft-Matter Additive Manufacturing.

    Science.gov (United States)

    Kabb, Christopher P; O'Bryan, Christopher S; Deng, Christopher C; Angelini, Thomas E; Sumerlin, Brent S

    2018-05-16

    Reversible covalent chemistry provides access to robust materials with the ability to be degraded and reformed upon exposure to an appropriate stimulus. Photoresponsive units are attractive for this purpose, as the spatial and temporal application of light is easily controlled. Coumarin derivatives undergo a [2 + 2] cycloaddition upon exposure to long-wave UV irradiation (365 nm), and this process can be reversed using short-wave UV light (254 nm). Therefore, polymers cross-linked by coumarin groups are excellent candidates as reversible covalent gels. In this work, copolymerization of coumarin-containing monomers with the hydrophilic comonomer N, N-dimethylacrylamide yielded water-soluble, linear polymers that could be cured with long-wave UV light into free-standing hydrogels, even in the absence of a photoinitiator. Importantly, the gels were reverted back to soluble copolymers upon short-wave UV irradiation. This process could be cycled, allowing for recycling and remolding of the hydrogel into additional shapes. Further, this hydrogel can be imprinted with patterns through a mask-based, post-gelation photoetching method. Traditional limitations of this technique, such as the requirement for uniform etching in one direction, have been overcome by combining these materials with a soft-matter additive manufacturing methodology. In a representative application of this approach, we printed solid structures in which the interior coumarin-cross-linked gel is surrounded by a nondegradable gel. Upon exposure to short-wave UV irradiation, the coumarin-cross-linked gel was reverted to soluble prepolymers that were washed away to yield hollow hydrogel objects.

  9. Collagen hydrogels incorporated with surface-aminated mesoporous nanobioactive glass: Improvement of physicochemical stability and mechanical properties is effective for hard tissue engineering.

    Science.gov (United States)

    El-Fiqi, Ahmed; Lee, Jae Ho; Lee, Eun-Jung; Kim, Hae-Won

    2013-12-01

    Collagen (Col) hydrogels have poor physicochemical and mechanical properties and are susceptible to substantial shrinkage during cell culture, which limits their potential applications in hard tissue engineering. Here, we developed novel nanocomposite hydrogels made of collagen and mesoporous bioactive glass nanoparticles (mBGns) with surface amination, and addressed the effects of mBGn addition (Col:mBG = 2:1, 1:1 and 1:2) and its surface amination on the physicochemical and mechanical properties of the hydrogels. The amination of mBGn was shown to enable chemical bonding with collagen molecules. As a result, the nanocomposite hydrogels exhibited a significantly improved physicochemical and mechanical stability. The hydrolytic and enzymatic degradation of the Col-mBGn hydrogels were slowed down due to the incorporation of mBGn and its surface amination. The mechanical properties of the hydrogels, specifically the resistance to loading as well as the stiffness, significantly increased with the addition of mBGn and its aminated form, as assessed by a dynamic mechanical analysis. Mesenchymal stem cells cultivated within the Col-mBGn hydrogels were highly viable, with enhanced cytoskeletal extensions, due to the addition of surface aminated mBGn. While the Col hydrogel showed extensive shrinkage (down to ∼20% of initial size) during a few days of culture, the shrinkage of the mBGn-added hydrogel was substantially reduced, and the aminated mBGn-added hydrogel had no observable shrinkage over 21 days. Results demonstrated the effective roles of aminated mBGn in significantly improving the physicochemical and mechanical properties of Col hydrogel, which are ultimately favorable for applications in stem cell culture for bone tissue engineering. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Polysaccharides and lignin based hydrogels with potential pharmaceutical use as a drug delivery system produced by a reactive extrusion process.

    Science.gov (United States)

    Farhat, Wissam; Venditti, Richard; Mignard, Nathalie; Taha, Mohamed; Becquart, Frederic; Ayoub, Ali

    2017-11-01

    Currently, there is very strong interest to replace synthetic polymers with biological macromolecules of natural source for applications that interact with humans or the environment. This research describes the development of drug delivery hydrogels from natural polymers, starch, lignin and hemicelluloses by means of reactive extrusion. The hydrogels show a strong swelling ability dependent on pH which may be used to control diffusion rates of water and small molecules in and out of the gel. Also the hydrogels degradation rates were studied in a physiological solution (pH 7.4) for 15days. The results indicated that for all three macromolecules, lower molecular weight and higher level of plasticizer both increase the rate of weight loss of the hydrogels. The degradation was extremely reduced when the polymers were extruded in the presence of a catalyst. Finally the dynamic mechanical analysis revealed that the degradation of the hydrogels induce a significant reduction in the compressive modulus. This study demonstrates the characteristics and potential of natural polymers as a drug release system. Published by Elsevier B.V.

  11. An interpenetrating HA/G/CS biomimic hydrogel via Diels-Alder click chemistry for cartilage tissue engineering.

    Science.gov (United States)

    Yu, Feng; Cao, Xiaodong; Zeng, Lei; Zhang, Qing; Chen, Xiaofeng

    2013-08-14

    In order to mimic the natural cartilage extracellular matrix, a novel biological degradable interpenetrating network hydrogel was synthesized from the gelatin (G), hyaluronic acid (HA) and chondroitin sulfate (CS) by Diels-Alder "click" chemistry. HA was modified with furylamine and G was modified with furancarboxylic acid respectively. (1)H NMR spectra and elemental analysis showed that the substitution degrees of HA-furan and G-furan were 71.5% and 44.5%. Then the hydrogels were finally synthesized by cross-linking furan-modified HA and G derivatives with dimaleimide poly(ethylene glycol) (MAL-PEG-MAL). The mechanical and degradation properties of the hydrogels could be tuned simply through varying the molar ratio between furan and maleimide. Rheological, mechanical and degradation studies demonstrated that the Diels-Alder "click" chemistry is an efficient method for preparing high performance biological interpenetrating hydrogels. This biomimic hydrogel with improved mechanical properties could have great potential applications in cartilage tissue engineering. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Promotion of peripheral nerve regeneration of a peptide compound hydrogel scaffold

    Directory of Open Access Journals (Sweden)

    Wei GJ

    2013-08-01

    Full Text Available Guo-Jun Wei,1 Meng Yao,1 Yan-Song Wang,1 Chang-Wei Zhou,1 De-Yu Wan,1 Peng-Zhen Lei,1 Jian Wen,1 Hong-Wei Lei,2 Da-Ming Dong1 1Department of Orthopaedics, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China; 2Department of Rheumatology, The 2nd Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China Background: Peripheral nerve injury is a common trauma, but presents a significant challenge to the clinic. Silk-based materials have recently become an important biomaterial for tissue engineering applications due to silk’s biocompatibility and impressive mechanical and degradative properties. In the present study, a silk fibroin peptide (SF16 was designed and used as a component of the hydrogel scaffold for the repair of peripheral nerve injury. Methods: The SF16 peptide’s structure was characterized using spectrophotometry and atomic force microscopy, and the SF16 hydrogel was analyzed using scanning electron microscopy. The effects of the SF16 hydrogel on the viability and growth of live cells was first assessed in vitro, on PC12 cells. The in vivo test model involved the repair of a nerve gap with tubular nerve guides, through which it was possible to identify if the SF16 hydrogel would have the potential to enhance nerve regeneration. In this model physiological saline was set as the negative control, and collagen as the positive control. Walking track analysis and electrophysiological methods were used to evaluate the functional recovery of the nerve at 4 and 8 weeks after surgery. Results: Analysis of the SF16 peptide’s characteristics indicated that it consisted of a well-defined secondary structure and exhibited self-assembly. Results of scanning electron microscopy showed that the peptide based hydrogel may represent a porous scaffold that is viable for repair of peripheral nerve injury. Analysis of cell culture also supported that the hydrogel was an effective

  13. Cartilaginous extracellular matrix-modified chitosan hydrogels for cartilage tissue engineering.

    Science.gov (United States)

    Choi, Bogyu; Kim, Soyon; Lin, Brian; Wu, Benjamin M; Lee, Min

    2014-11-26

    Cartilaginous extracellular matrix (ECM) components such as type-II collagen (Col II) and chondroitin sulfate (CS) play a crucial role in chondrogenesis. However, direct clinical use of natural Col II or CS as scaffolds for cartilage tissue engineering is limited by their instability and rapid enzymatic degradation. Here, we investigate the incorporation of Col II and CS into injectable chitosan hydrogels designed to gel upon initiation by exposure to visible blue light (VBL) in the presence of riboflavin. Unmodified chitosan hydrogel supported proliferation and deposition of cartilaginous ECM by encapsulated chondrocytes and mesenchymal stem cells. The incorporation of native Col II or CS into chitosan hydrogels further increased chondrogenesis. The incorporation of Col II, in particular, was found to be responsible for the enhanced cellular condensation and chondrogenesis observed in modified hydrogels. This was mediated by integrin α10 binding to Col II, increasing cell-matrix adhesion. These findings demonstrate the potential of cartilage ECM-modified chitosan hydrogels as biomaterials to promote cartilage regeneration.

  14. Injectable alginate-O-carboxymethyl chitosan/nano fibrin composite hydrogels for adipose tissue engineering.

    Science.gov (United States)

    Jaikumar, Dhanya; Sajesh, K M; Soumya, S; Nimal, T R; Chennazhi, K P; Nair, Shantikumar V; Jayakumar, R

    2015-03-01

    Injectable, biodegradable scaffolds are required for soft tissue reconstruction owing to its minimally invasive approach. Such a scaffold can mimic the native extracellular matrix (ECM), provide uniform distribution of cells and overcome limitations like donor site morbidity, volume loss, etc. So, here we report two classes of biocompatible and biodegradable hydrogel blend systems namely, Alginate/O-carboxymethyl chitosan (O-CMC) and Alginate/poly (vinyl alcohol) (PVA) with the inclusion of fibrin nanoparticles in each. The hydrogels were prepared by ionic cross-linking method. The developed hydrogels were compared in terms of its swelling ratio, degradation profile, compressive strength and elastic moduli. From these preliminary findings, it was concluded that Alginate/O-CMC formed a better blend for tissue engineering applications. The potential of the formed hydrogel as an injectable scaffold was revealed by the survival of adipose derived stem cells (ADSCs) on the scaffold by its adhesion, proliferation and differentiation into adipocytes. Cell differentiation studies of fibrin incorporated hydrogel scaffolds showed better differentiation was confirmed by Oil Red O staining technique. These injectable gels have potential in soft tissue regeneration. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Multifunctional magnetic-responsive hydrogels to engineer tendon-to-bone interface.

    Science.gov (United States)

    Silva, Elsa D; Babo, Pedro S; Costa-Almeida, Raquel; Domingues, Rui M A; Mendes, Bárbara B; Paz, Elvira; Freitas, Paulo; Rodrigues, Márcia T; Granja, Pedro L; Gomes, Manuela E

    2017-06-11

    Photocrosslinkable magnetic hydrogels are attracting great interest for tissue engineering strategies due to their versatility and multifunctionality, including their remote controllability ex vivo, thus enabling engineering complex tissue interfaces. This study reports the development of a photocrosslinkable magnetic responsive hydrogel made of methacrylated chondroitin sulfate (MA-CS) enriched with platelet lysate (PL) with tunable features, envisioning their application in tendon-to-bone interface. MA-CS coated iron-based magnetic nanoparticles were incorporated to provide magnetic responsiveness to the hydrogel. Osteogenically differentiated adipose-derived stem cells and/or tendon-derived cells were encapsulated within the hydrogel, proliferating and expressing bone- and tendon-related markers. External magnetic field (EMF) application modulated the swelling, degradation and release of PL-derived growth factors, and impacted both cell morphology and the expression and synthesis of tendon- and bone-like matrix with a more evident effect in co-cultures. Overall, the developed magnetic responsive hydrogel represents a potential cell carrier system for interfacial tissue engineering with EMF-controlled properties. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Radiologic Findings in Hydrated Hydrogel Buckles

    International Nuclear Information System (INIS)

    Lee, Sung Bok; Lee, Nam Ho; Jo, Young Joon; Kim, Jung Yeul; Lee, Yeon Hee; Kim, Song Soo

    2008-01-01

    Hydrogel buckles, which are used in scleral buckling surgery for retinal detachment, have been associated with late complications after successful retinal reattachment surgery, including strabismus, extraocular motility restriction, extrusion through the eyelid or conjunctiva, intraocular erosion, and scleral erosion. Hydrogel buckles sometimes appear as well-marginated, circumferential, lobulating, contoured cystic masses mimicking orbital cysts on orbital CT or MRI. We report the radiologic findings in 5 patients whose hydrogel buckles needed to be differentiated from orbital cysts

  17. Radiologic Findings in Hydrated Hydrogel Buckles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Bok; Lee, Nam Ho; Jo, Young Joon; Kim, Jung Yeul; Lee, Yeon Hee; Kim, Song Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2008-11-15

    Hydrogel buckles, which are used in scleral buckling surgery for retinal detachment, have been associated with late complications after successful retinal reattachment surgery, including strabismus, extraocular motility restriction, extrusion through the eyelid or conjunctiva, intraocular erosion, and scleral erosion. Hydrogel buckles sometimes appear as well-marginated, circumferential, lobulating, contoured cystic masses mimicking orbital cysts on orbital CT or MRI. We report the radiologic findings in 5 patients whose hydrogel buckles needed to be differentiated from orbital cysts.

  18. Polysaccharides as Hydrogel and Bioplastics. Chapter 4

    International Nuclear Information System (INIS)

    Kamaruddin Hashim; Sarada Idris; Norzita Yacob; Maznah Mahmud

    2017-01-01

    The use of radiation technology in producing hydrogel is increasingly popular nowadays. The hydrogel which produce through the radiation method has it own advantages. For example, easy to operate, reduce the cost production and also decrease the harmful chemical usage such as monomer. The cross-linking bonds which has been produced this hydrogel during the irradiation process can be controlled by the radiation dosage even though using the same material and composition.

  19. Design, fabrication and characterization of oxidized alginate-gelatin hydrogels for muscle tissue engineering applications.

    Science.gov (United States)

    Baniasadi, Hossein; Mashayekhan, Shohreh; Fadaoddini, Samira; Haghirsharifzamini, Yasamin

    2016-07-01

    In this study, we reported the preparation of self cross-linked oxidized alginate-gelatin hydrogels for muscle tissue engineering. The effect of oxidation degree (OD) and oxidized alginate/gelatin (OA/GEL) weight ratio were examined and the results showed that in the constant OA/GEL weight ratio, both cross-linking density and Young's modulus enhanced by increasing OD due to increment of aldehyde groups. Furthermore, the degradation rate was increased with increasing OD probably due to decrement in alginate molecular weight during oxidation reaction facilitated degradation of alginate chains. MTT cytotoxicity assays performed on Wharton's Jelly-derived umbilical cord mesenchymal stem cells cultured on hydrogels with OD of 30% showed that the highest rate of cell proliferation belong to hydrogel with OA/GEL weight ratio of 30/70. Overall, it can be concluded from all obtained results that the prepared hydrogel with OA/GEL weight ratio and OD of 30/70 and 30%, respectively, could be proper candidate for use in muscle tissue engineering. © The Author(s) 2016.

  20. Influence of residual composition on the structure and properties of extracellular matrix derived hydrogels.

    Science.gov (United States)

    Claudio-Rizo, Jesús A; Rangel-Argote, Magdalena; Castellano, Laura E; Delgado, Jorge; Mata-Mata, José L; Mendoza-Novelo, Birzabith

    2017-10-01

    In this work, hydrolysates of extracellular matrix (hECM) were obtained from rat tail tendon (TR), bovine Achilles tendon (TAB), porcine small intestinal submucosa (SIS) and bovine pericardium (PB), and they were polymerized to generate ECM hydrogels. The composition of hECM was evaluated by quantifying the content of sulphated glycosaminoglycans (sGAG), fibronectin and laminin. The polymerization process, structure, physicochemical properties, in vitro degradation and biocompatibility were studied and related to their composition. The results indicated that the hECM derived from SIS and PB were significantly richer in sGAG, fibronectin and laminin, than those derived from TAB and TR. These differences in hECM composition influenced the polymerization and the structural characteristics of the fibrillar gel network. Consequently, the swelling, mechanics and degradation of the hydrogels showed a direct relationship with the remaining composition. Moreover, the cytocompatibility and the secretion of transforming growth factor beta-1 (TGF-β1) by macrophages were enhanced in hydrogels with the highest residual content of ECM biomolecules. The results of this work evidenced the role of the ECM molecules remaining after both decellularization and hydrolysis steps to produce tissue derived hydrogels with structure and properties tailored to enhance their performance in tissue engineering and regenerative medicine applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Drug delivery systems based on biocompatible imino-chitosan hydrogels for local anticancer therapy.

    Science.gov (United States)

    Ailincai, Daniela; Tartau Mititelu, Liliana; Marin, Luminita

    2018-11-01

    A series of drug delivery systems were prepared by chitosan hydrogelation with citral in the presence of an antineoplastic drug: 5-fluorouracil. The dynamic covalent chemistry of the imine linkage allowed the obtaining of supramolecular tridimensional architectures in which the drug has been homogenously dispersed. Fourier-transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WXRD) and polarized light microscopy (POM) measurements were used in order to follow the hydrogelation and drug encapsulation processes. The ability of the prepared systems to release the drug has been investigated by UV-Vis spectroscopy using a calibration curve and by fitting the results with different mathematic models. To mimic the behavior of the hydrogel matrix in bio-environmental conditions in view of applications, their enzymatic degradability was monitored in the presence of lysozyme. The in vivo side effects of the systems, in terms of their influence on the blood elements, biochemical and immune parameters were monitored on white Swiss mice by intraperitoneal administration of the injectable obtained hydrogels. All the characteristics of the obtained systems, such as micro-porous morphology, uniform drug encapsulation, enzymatic degradability, lack of side effects, other than the one of the drug itself, along with their ability to release the drug in a sustained manner proved that these material meet the requirements for the development of drug delivery systems, making them suitable for being applied in intraperitoneal chemotherapy.

  2. Micromechanical Characterization of Hydrogels Undergoing Swelling and Dissolution at Alkaline pH

    Directory of Open Access Journals (Sweden)

    Wei Hu

    2017-11-01

    Full Text Available The swelling of polyelectrolyte hydrogels usually depends on the pH, and if the pH is high enough degradation can occur. A microindentation device was developed to dynamically test these processes in whey protein isolate hydrogels at alkaline pH 7–14. At low alkaline pH the shear modulus decreases during swelling, consistent with rubber elasticity theory, yet when chemical degradation occurs at pH ≥ 11.5 the modulus decreases quickly and extensively. The apparent modulus was constant with the indentation depth when swelling predominates, but gradients were observed when fast chemical degradation occurs at 0.05–0.1 M NaOH. In addition, these profiles were constant with time when dissolution rates are also constant, the first evidence that a swollen layer with steady state mechanical properties is achieved despite extensive dissolution. At >0.5 M NaOH, we provide mechanical evidence showing that most interactions inside the gels are destroyed, gels were very weak and hardly swell, yet they still dissolve very slowly. Microindentation can provide complementary valuable information to study the degradation of hydrogels.

  3. Near-Infrared Light-Sensitive Polyvinyl Alcohol Hydrogel Photoresist for Spatiotemporal Control of Cell-Instructive 3D Microenvironments.

    Science.gov (United States)

    Qin, Xiao-Hua; Wang, Xiaopu; Rottmar, Markus; Nelson, Bradley J; Maniura-Weber, Katharina

    2018-03-01

    Advanced hydrogel systems that allow precise control of cells and their 3D microenvironments are needed in tissue engineering, disease modeling, and drug screening. Multiphoton lithography (MPL) allows true 3D microfabrication of complex objects, but its biological application requires a cell-compatible hydrogel resist that is sufficiently photosensitive, cell-degradable, and permissive to support 3D cell growth. Here, an extremely photosensitive cell-responsive hydrogel composed of peptide-crosslinked polyvinyl alcohol (PVA) is designed to expand the biological applications of MPL. PVA hydrogels are formed rapidly by ultraviolet light within 1 min in the presence of cells, providing fully synthetic matrices that are instructive for cell-matrix remodeling, multicellular morphogenesis, and protease-mediated cell invasion. By focusing a multiphoton laser into a cell-laden PVA hydrogel, cell-instructive extracellular cues are site-specifically attached to the PVA matrix. Cell invasion is thus precisely guided in 3D with micrometer-scale spatial resolution. This robust hydrogel enables, for the first time, ultrafast MPL of cell-responsive synthetic matrices at writing speeds up to 50 mm s -1 . This approach should enable facile photochemical construction and manipulation of 3D cellular microenvironments with unprecedented flexibility and precision. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. An injectable and biodegradable hydrogel based on poly(α,β-aspartic acid) derivatives for localized drug delivery.

    Science.gov (United States)

    Lu, Caicai; Wang, Xiaojuan; Wu, Guolin; Wang, Jingjing; Wang, Yinong; Gao, Hui; Ma, Jianbiao

    2014-03-01

    An injectable hydrogel via hydrazone cross-linking was prepared under mild conditions without addition of cross-linker or catalyst. Hydrazine and aldehyde modified poly(aspartic acid)s were used as two gel precursors. Both of them are water-soluble and biodegradable polymers with a protein-like structure, and obtained by aminolysis reaction of polysuccinimide. The latter can be prepared by thermal polycondensation of aspartic acid. Hydrogels were prepared in PBS solution and characterized by different methods including gel content and swelling, Fourier transformed-infrared spectroscopy, and in vitro degradation experiment. A scanning electron microscope viewed the interior morphology of the obtained hydrogels, which showed porous three-dimensional structures. Different porous sizes were present, which could be well controlled by the degree of aldehyde substitution in precursor poly(aspartic acid) derivatives. The doxorubicin-loaded hydrogels were prepared and showed a pH-sensitive release profile. The release rate can be accelerated by decreasing the environmental pH from a physiological to a weak acidic condition. Moreover, the cell adhesion and growth behaviors on the hydrogel were studied and the polymeric hydrogel showed good biocompatibility. Copyright © 2013 Wiley Periodicals, Inc.

  5. Gum ghatti and poly(acrylamide-co-acrylic acid) based biodegradable hydrogel-evaluation of the flocculation and adsorption properties

    CSIR Research Space (South Africa)

    Mittal, H

    2015-10-01

    Full Text Available removal of cationic dyes from the aqueous solutions and it was found to adsorb 96% of malachite green and 99% of methyl violet. Finally, the hydrogel polymer was subjected to biodegradation using the composting method and 91.77% degradation was achieved...

  6. Hydrogel nanoparticle based immunoassay

    Science.gov (United States)

    Liotta, Lance A; Luchini, Alessandra; Petricoin, Emanuel F; Espina, Virginia

    2015-04-21

    An immunoassay device incorporating porous polymeric capture nanoparticles within either the sample collection vessel or pre-impregnated into a porous substratum within fluid flow path of the analytical device is presented. This incorporation of capture particles within the immunoassay device improves sensitivity while removing the requirement for pre-processing of samples prior to loading the immunoassay device. A preferred embodiment is coreshell bait containing capture nanoparticles which perform three functions in one step, in solution: a) molecular size sieving, b) target analyte sequestration and concentration, and c) protection from degradation. The polymeric matrix of the capture particles may be made of co-polymeric materials having a structural monomer and an affinity monomer, the affinity monomer having properties that attract the analyte to the capture particle. This device is useful for point of care diagnostic assays for biomedical applications and as field deployable assays for environmental, pathogen and chemical or biological threat identification.

  7. Evaluation of Photocrosslinked Lutrol Hydrogel for Tissue Printing applications

    NARCIS (Netherlands)

    Fedorovich, Natalja E.; Swennen, Ives; Girones, Jordi; Moroni, Lorenzo; van Blitterswijk, Clemens; Schacht, Etienne; Alblas, Jacqueline; Dhert, Wouter J.A.

    2009-01-01

    Application of hydrogels in tissue engineering and innovative strategies such as organ printing, which is based on layered 3D deposition of cell-laden hydrogels, requires design of novel hydrogel matrices. Hydrogel demands for 3D printing include: 1) preservation of the printed shape after the

  8. A novel platelet lysate hydrogel for endothelial cell and mesenchymal stem cell-directed neovascularization.

    Science.gov (United States)

    Robinson, Scott T; Douglas, Alison M; Chadid, Tatiana; Kuo, Katie; Rajabalan, Ajai; Li, Haiyan; Copland, Ian B; Barker, Thomas H; Galipeau, Jacques; Brewster, Luke P

    2016-05-01

    Mesenchymal stem cells (MSC) hold promise in promoting vascular regeneration of ischemic tissue in conditions like critical limb ischemia of the leg. However, this approach has been limited in part by poor cell retention and survival after delivery. New biomaterials offer an opportunity to localize cells to the desired tissue after delivery, but also to improve cell survival after delivery. Here we characterize the mechanical and microstructural properties of a novel hydrogel composed of pooled human platelet lysate (PL) and test its ability to promote MSC angiogenic activity using clinically relevant in vitro and in vivo models. This PL hydrogel had comparable storage and loss modulus and behaved as a viscoelastic solid similar to fibrin hydrogels despite having 1/4-1/10th the fibrin content of standard fibrin gels. Additionally, PL hydrogels enabled sustained release of endogenous PDGF-BB for up to 20days and were resistant to protease degradation. PL hydrogel stimulated pro-angiogenic activity by promoting human MSC growth and invasion in a 3D environment, and enhancing endothelial cell sprouting alone and in co-culture with MSCs. When delivered in vivo, the combination of PL and human MSCs improved local tissue perfusion after 8days compared to controls when assessed with laser Doppler perfusion imaging in a murine model of hind limb ischemia. These results support the use of a PL hydrogel as a scaffold for MSC delivery to promote vascular regeneration. Innovative strategies for improved retention and viability of mesenchymal stem cells (MSCs) are needed for cellular therapies. Human platelet lysate is a potent serum supplement that improves the expansion of MSCs. Here we characterize our novel PL hydrogel's desirable structural and biologic properties for human MSCs and endothelial cells. PL hydrogel can localize cells for retention in the desired tissue, improves cell viability, and augments MSCs' angiogenic activity. As a result of these unique traits, PL

  9. Investigating hydrogel dosimeter decomposition by chemical methods

    International Nuclear Information System (INIS)

    Jordan, Kevin

    2015-01-01

    The chemical oxidative decomposition of leucocrystal violet micelle hydrogel dosimeters was investigated using the reaction of ferrous ions with hydrogen peroxide or sodium bicarbonate with hydrogen peroxide. The second reaction is more effective at dye decomposition in gelatin hydrogels. Additional chemical analysis is required to determine the decomposition products

  10. Thermal Transport in Soft PAAm Hydrogels

    Directory of Open Access Journals (Sweden)

    Ni Tang

    2017-12-01

    Full Text Available As the interface between human and machine becomes blurred, hydrogel incorporated electronics and devices have emerged to be a new class of flexible/stretchable electronic and ionic devices due to their extraordinary properties, such as softness, mechanically robustness, and biocompatibility. However, heat dissipation in these devices could be a critical issue and remains unexplored. Here, we report the experimental measurements and equilibrium molecular dynamics simulations of thermal conduction in polyacrylamide (PAAm hydrogels. The thermal conductivity of PAAm hydrogels can be modulated by both the effective crosslinking density and water content in hydrogels. The effective crosslinking density dependent thermal conductivity in hydrogels varies from 0.33 to 0.51 Wm−1K−1, giving a 54% enhancement. We attribute the crosslinking effect to the competition between the increased conduction pathways and the enhanced phonon scattering effect. Moreover, water content can act as filler in polymers which leads to nearly 40% enhancement in thermal conductivity in PAAm hydrogels with water content vary from 23 to 88 wt %. Furthermore, we find the thermal conductivity of PAAm hydrogel is insensitive to temperature in the range of 25–40 °C. Our study offers fundamental understanding of thermal transport in soft materials and provides design guidance for hydrogel-based devices.

  11. Highly Stretchable, Strain Sensing Hydrogel Optical Fibers.

    Science.gov (United States)

    Guo, Jingjing; Liu, Xinyue; Jiang, Nan; Yetisen, Ali K; Yuk, Hyunwoo; Yang, Changxi; Khademhosseini, Ali; Zhao, Xuanhe; Yun, Seok-Hyun

    2016-12-01

    A core-clad fiber made of elastic, tough hydrogels is highly stretchable while guiding light. Fluorescent dyes are easily doped into the hydrogel fiber by diffusion. When stretched, the transmission spectrum of the fiber is altered, enabling the strain to be measured and also its location. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Synthesis and characterization of superabsorbent hydrogel based ...

    African Journals Online (AJOL)

    The hydrogels structure was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effect of grafting variables, that is, AA/AN weight ratio and concentration of MBA and APS, was systematically optimized to achieve a hydrogel with ...

  13. Application of collagen hydrogel/sponge scaffold facilitates periodontal wound healing in class II furcation defects in beagle dogs.

    Science.gov (United States)

    Kosen, Y; Miyaji, H; Kato, A; Sugaya, T; Kawanami, M

    2012-10-01

    A three-dimensional scaffold may play an important role in periodontal tissue engineering. We prepared bio-safe collagen hydrogel, which exhibits properties similar to those of native extracellular matrix. The aim of this study was to examine the effect of implantation of collagen hydrogel/sponge scaffold on periodontal wound healing in class II furcation defects in dogs. The collagen hydrogel/sponge scaffold was prepared by injecting collagen hydrogel, cross-linked to the ascorbate-copper ion system, into a collagen sponge. Class II furcation defects (of 5 mm depth and 3 mm width) were surgically created in beagle dogs. The exposed root surface was planed and demineralized with EDTA. In the experimental group, the defect was filled with collagen hydrogel/sponge scaffold. In the control group, no implantation was performed. Histometric parameters were evaluated 2 and 4 wk after surgery. At 2 wk, the collagen hydrogel/sponge scaffold displayed high biocompatibility and biodegradability with numerous cells infiltrating the scaffold. In the experimental group, reconstruction of alveolar bone and cementum was frequently observed 4 wk after surgery. Periodontal ligament tissue was also re-established between alveolar bone and cementum. Volumes of new bone, new cementum and new periodontal ligament were significantly greater in the experimental group than in the control group. In addition, epithelial down-growth was suppressed by application of collagen hydrogel. The collagen hydrogel/sponge scaffold possessed high tissue compatibility and degradability. Implantation of the scaffold facilitated periodontal wound healing in class II furcation defects in beagle dogs. © 2012 John Wiley & Sons A/S.

  14. Cross-Linked Hydrogel for Pharmaceutical Applications: A Review

    Directory of Open Access Journals (Sweden)

    Rabinarayan parhi

    2017-12-01

    Full Text Available Hydrogels are promising biomaterials because of their important qualities such as biocompatibility, biodegradability, hydrophilicity and non-toxicity. These qualities make hydrogels suitable for application in medical and pharmaceutical field. Recently, a tremendous growth of hydrogel application is seen, especially as gel and patch form, in transdermal drug delivery. This review mainly focuses on the types of hydrogels based on cross-linking and; secondly to describe the possible synthesis methods to design hydrogels for different pharmaceutical applications. The synthesis and chemistry of these hydrogels are discussed using specific pharmaceutical examples. The structure and water content in a typical hydrogel have also been discussed.

  15. A phytomodulatory hydrogel with enhanced healing effects.

    Science.gov (United States)

    Vasconcelos, Mirele S; Souza, Tamiris F G; Figueiredo, Ingrid S; Sousa, Emília T; Sousa, Felipe D; Moreira, Renato A; Alencar, Nylane M N; Lima-Filho, José V; Ramos, Márcio V

    2018-04-01

    The healing performance of a hydrogel composed of hemicelluloses extracted from seeds of Caesalpinia pulcherrima (Fabaceae) and mixed with phytomodulatory proteins obtained from the latex of Calotropis procera was characterized on excisional wounds. The hydrogel did not induce dermal irritability. When topically used on excisional wounds, the hydrogel enhanced healing by wound contraction. Histology and the measurement of inflammatory mediators (myeloperoxidase, interleukin-1β, and interleukin-6) suggested that the inflammatory phase of the healing process was intensified, stimulating fibroplasia and neovascularization (proliferative phase) and tissue remodeling by increasing new collagen fiber deposition. In addition, reduction on levels of malondialdehyde in the groups that the hydrogel was applied suggested that the oxidative stress was reduced. The hydrogel performed better than the reference drug used, as revealed by the extended thickness of the remodeled epithelium. Copyright © 2018 John Wiley & Sons, Ltd.

  16. Arct'Alg release from hydrogel membranes

    International Nuclear Information System (INIS)

    Amaral, Renata H.; Rogero, Sizue O.; Shihomatsu, Helena M.; Lugao, Ademar B.

    2009-01-01

    The hydrogel properties make them attractive for a variety of biomedical and pharmaceutical applications, primarily in drug delivery system. Synthetic hydrogels have been studied to develop new devices for drugs or cosmetic active agents release. Arct'Alg R is an extract derived from red algae biomass which has antioxidant, anti-inflammatory and tissue regeneration stimulant properties. This extract was incorporated to poly(N-vinyl pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) hydrogel membranes obtained by gamma rays crosslinking technique. The ionizing radiation presents the advantage to occur polymerization and sterilization simultaneously in the same process. The aim of this work was the in vitro release kinetic study of Arct'Alg R from hydrogel membranes during 24 hours to verify the possibility of use in cosmetic and dermatological treatments. Results showed that about 50% and 30% of incorporated Arct'Alg R was released from PVP and PVA hydrogel membrane devices respectively. (author)

  17. Hybrid hydrogels produced by ionizing radiation technique

    Science.gov (United States)

    Oliveira, M. J. A.; Amato, V. S.; Lugão, A. B.; Parra, D. F.

    2012-09-01

    The interest in biocompatible hydrogels with particular properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl and 0.5, 1.0, 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopy (FTIR) and swelling in solutions of different pH. The membranes have no toxicity. The nano-clay influences directly the equilibrium swelling.

  18. Self-assembling Fmoc dipeptide hydrogel for in situ 3D cell culturing

    Directory of Open Access Journals (Sweden)

    Akpe Victor

    2007-12-01

    Full Text Available Abstract Background Conventional cell culture studies have been performed on 2D surfaces, resulting in flat, extended cell growth. More relevant studies are desired to better mimic 3D in vivo tissue growth. Such realistic environments should be the aim of any cell growth study, requiring new methods for culturing cells in vitro. Cell biology is also tending toward miniaturization for increased efficiency and specificity. This paper discusses the application of a self-assembling peptide-derived hydrogel for use as a 3D cell culture scaffold at the microscale. Results Phenylalanine derivative hydrogel formation was seen to occur in multiple dispersion media. Cells were immobilized in situ within microchambers designed for cell analysis. Use of the highly biocompatible hydrogel components and simplistic procedures significantly reduced the cytotoxic effects seen with alternate 3D culture materials and microstructure loading methods. Cells were easily immobilized, sustained and removed from microchambers. Differences in growth morphology were seen in the cultured cells, owing to the 3-dimentional character of the gel structure. Degradation improved the removal of hydrogel from the microstructures, permitting reuse of the analysis platforms. Conclusion Self-assembling diphenylalanine derivative hydrogel provided a method to dramatically reduce the typical difficulties of microculture formation. Effective generation of patterned 3D cultures will lead to improved cell study results by better modeling in vivo growth environments and increasing efficiency and specificity of cell studies. Use of simplified growth scaffolds such as peptide-derived hydrogel should be seen as highly advantageous and will likely become more commonplace in cell culture methodology.

  19. A facile route to the synthesis of anilinic electroactive colloidal hydrogels for neural tissue engineering applications.

    Science.gov (United States)

    Zarrintaj, Payam; Urbanska, Aleksandra M; Gholizadeh, Saman Seyed; Goodarzi, Vahabodin; Saeb, Mohammad Reza; Mozafari, Masoud

    2018-04-15

    An innovative drug-loaded colloidal hydrogel was synthesized for applications in neural interfaces in tissue engineering by reacting carboxyl capped aniline dimer and gelatin molecules. Dexamethasone was loaded into the gelatin-aniline dimer solution as a model drug to form an in situ drug-loaded colloidal hydrogel. The conductivity of the hydrogel samples fluctuated around 10 -5  S/cm which appeared suitable for cellular activities. Cyclic voltammetry was used for electroactivity determination, in which 2 redox states were observed, suggesting that the short chain length and steric hindrance prevented the gel from achieving a fully oxidized state. Rheological data depicted the modulus decreasing with aniline dimer increment due to limited hydrogen bonds accessibility. Though the swelling ratio of pristine gelatin (600%) decreased by the introduction and increasing the concentration of aniline dimer because of its hydrophobic nature, it took the value of 300% at worst, which still seems promising for drug delivery uses. Degradation rate of hydrogel was similarly decreased by adding aniline dimer. Drug release was evaluated in passive and stimulated patterns demonstrating tendency of aniline dimer to form a vesicle that controls the drug release behavior. The optimal cell viability, proper cell attachment and neurite extension was achieved in the case of hydrogel containing 10 wt% aniline dimer. Based on tissue/organ behavior, it was promisingly possible to adjust the characteristics of the hydrogels for an optimal drug release. The outcome of this simple and effective approach can potentially offer additional tunable characteristics for recording and stimulating purposes in neural interfaces. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Enhanced intestinal anastomotic healing with gelatin hydrogel incorporating basic fibroblast growth factor.

    Science.gov (United States)

    Hirai, Kenjiro; Tabata, Yasuhiko; Hasegawa, Suguru; Sakai, Yoshiharu

    2016-10-01

    Anastomotic leakage is a common complication of intestinal surgery. In an attempt to resolve this issue, a promising approach is enhancement of anastomotic wound healing. A method for controlled release of basic fibroblast growth factor (bFGF) using a gelatin hydrogel was developed with the objective of investigating the effects of this technology on intestinal anastomotic healing. The small intestine of Wistar rats was cut, end-to-end anastomosis was performed and rats were divided into three groups: bFGF group (anastomosis wrapped with a hydrogel sheet incorporating bFGF), PBS group (wrapped with a sheet incorporating phosphate-buffered saline solution) and NT group (no additional treatment). Degradation profiles of gelatin hydrogels in vivo and histological examinations were performed using gelatin hydrogels with various water contents and bFGF concentrations to define the optimal bFGF dose and hydrogel biodegradability. The anastomotic wound healing process was evaluated by histological examinations, adhesion-related score and bursting pressure. The optimal water content of the hydrogel and bFGF dose was determined as 96% and 30 µg per sheet, respectively. Application of bFGF significantly enhanced neovascularization, fibroblast infiltration and collagen production around the anastomotic site when compared with the other groups. Bursting pressure was significantly increased in the bFGF group. No significant difference was observed in the adhesion-related score among the groups and no anastomotic obstruction and leakage were observed. Therefore controlled release of bFGF enhanced healing of an intestinal anastomosis during the early postoperative period and is a promising method to suppress anastomotic leakage. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Photocrosslinked PLA-PEO-PLA Hydrogels from Self-Assembled Physical Networks: Mechanical Properties and Influence of Assumed Constitutive Relationships

    Science.gov (United States)

    Sanabria-DeLong, Naomi; Crosby, Alfred J.; Tew, Gregory N.

    2014-01-01

    Poly(lactide) – block – poly(ethylene oxide) – block – poly(lactide) [PLA-PEO-PLA] triblock copolymers are known to form physical hydrogels in water, due to the polymer's amphiphilicity. Their mechanical properties, biocompatibility, and biodegradability have made them attractive for use as soft tissue scaffolds. However, the network junction points are not covalently crosslinked and in a highly aqueous environment these hydrogels adsorb more water, transform from gel to sol, and lose the designed mechanical properties. In this report, a hydrogel was formed by using a novel two step approach. In the first step end-functionalized PLA-PEOPLA triblock was self-assembled into a physical hydrogel through hydrophobic micelle network junctions, and then, in the second step, this self-assembled physical network structure was locked into place by photocrosslinking the terminal acrylate groups. In contrast to physical hydrogels, the photocrosslinked gels remained intact in phosphate buffered solution at body temperature. The swelling, degradation, and mechanical properties were characterized and demonstrated extended degradation time (~ 65 days), exponential decrease in modulus with degradation time, and tunable shear modulus (1.6 – 133 kPa) by varying concentration. We also discuss the various constitutive relationships (Hookean, Neo-Hookean, and Mooney-Rivlin) that can be used to describe the stress-strain behavior of these hydrogels. The chosen model and assumptions used for data fitting influences the obtained modulus values by as much as a factor of 3.5, demonstrating the importance of clearly stating one's data fitting parameters so that accurate comparisons can be made within the literature. PMID:18817440

  2. Synthesis of PVA Hydrogel for Prosthetic Discus Nucleus Pulposus: Formation of Interpenetrating Polymer Network (IPN) PVA Hydrogel by Gamma Rays

    International Nuclear Information System (INIS)

    Darwis, Darmawan; Erizal; Lely Hardiningsih; Razzak, Mirzan T.

    2004-01-01

    Research on synthesis of IPN PVA hydrogel for using as prosthetic discus nucleus has been carried out. Base hydrogel network (network I) was made by reacting the solution of polyvinyl alcohol (PVA) 10 - 15 % w/w with formaldehyde at 80 o C for several hours. Hydrogel network II (as IPN network) was then made by immersion of base hydrogel into polymer solution (PVP or PVA) until hydrogel swell to equilibrium volume. The hydrogel then irradiated using gamma rays at various doses. The results show that IPN PVA-PVP and IPN PVA-PVP hydrogels have higher compression strength compared to base hydrogel. IPN PVA-PVA hydrogel made by irradiating base hydrogel (immersed into polymer solution) with 25, 50 and 100 kGy have compression strength at 5 mm displacement 2.72; 2.83; and 3.25 kg/cm 2 respectively, While base hydrogel has compression strength of 1.75 kg/cm 2 . IPN PVA-PVP and PVA-PVA hydrogels made by irradiating base hydrogel with 100 kGy still retain high water content i.e. 72 and 74 % respectively. Beside that they show good re-absorption property after compression treatment that is hydrogel can return to the original shape after compressed to 12 mm displacement (80% of initial height on hydrogel) at relatively short time, less than 15 minutes. (author)

  3. Biocompatibility and intradiscal application of a thermoreversible celecoxib-loaded poly-N-isopropylacrylamide MgFe-layered double hydroxide hydrogel in a canine model.

    Science.gov (United States)

    Willems, Nicole; Yang, Hsiao-Yin; Langelaan, Marloes L P; Tellegen, Anna R; Grinwis, Guy C M; Kranenburg, Hendrik-Jan C; Riemers, Frank M; Plomp, Saskia G M; Craenmehr, Eric G M; Dhert, Wouter J A; Papen-Botterhuis, Nicole E; Meij, Björn P; Creemers, Laura B; Tryfonidou, Marianna A

    2015-08-20

    Chronic low back pain due to intervertebral disc (IVD) degeneration is associated with increased levels of inflammatory mediators. Current medical treatment consists of oral anti-inflammatory drugs to alleviate pain. In this study, the efficacy and safety of a novel thermoreversible poly-N-isopropylacrylamide MgFe-layered double hydroxide (pNIPAAM MgFe-LDH) hydrogel was evaluated for intradiscal controlled delivery of the selective cyclooxygenase (COX) 2 inhibitor and anti-inflammatory drug celecoxib (CXB). Degradation, release behavior, and the ability of a CXB-loaded pNIPAAM MgFe-LDH hydrogel to suppress prostaglandin E2 (PGE2) levels in a controlled manner in the presence of a proinflammatory stimulus (TNF-α) were evaluated in vitro. Biocompatibility was evaluated histologically after subcutaneous injection in mice. Safety of intradiscal application of the loaded and unloaded hydrogels was studied in a canine model of spontaneous mild IVD degeneration by histological, biomolecular, and biochemical evaluation. After the hydrogel was shown to be biocompatible and safe, an in vivo dose-response study was performed in order to determine safety and efficacy of the pNIPAAM MgFe-LDH hydrogel for intradiscal controlled delivery of CXB. CXB release correlated to hydrogel degradation in vitro. Furthermore, controlled release from CXB-loaded hydrogels was demonstrated to suppress PGE2 levels in the presence of TNF-α. The hydrogel was shown to exhibit a good biocompatibility upon subcutaneous injection in mice. Upon intradiscal injection in a canine model, the hydrogel exhibited excellent biocompatibility based on histological evaluation of the treated IVDs. Gene expression and biochemical analyses supported the finding that no substantial negative effects of the hydrogel were observed. Safety of application was further confirmed by the absence of clinical symptoms, IVD herniation or progression of degeneration. Controlled release of CXB resulted in a nonsignificant

  4. Bioinspired Nanocomposite Hydrogels with Highly Ordered Structures.

    Science.gov (United States)

    Zhao, Ziguang; Fang, Ruochen; Rong, Qinfeng; Liu, Mingjie

    2017-12-01

    In the human body, many soft tissues with hierarchically ordered composite structures, such as cartilage, skeletal muscle, the corneas, and blood vessels, exhibit highly anisotropic mechanical strength and functionality to adapt to complex environments. In artificial soft materials, hydrogels are analogous to these biological soft tissues due to their "soft and wet" properties, their biocompatibility, and their elastic performance. However, conventional hydrogel materials with unordered homogeneous structures inevitably lack high mechanical properties and anisotropic functional performances; thus, their further application is limited. Inspired by biological soft tissues with well-ordered structures, researchers have increasingly investigated highly ordered nanocomposite hydrogels as functional biological engineering soft materials with unique mechanical, optical, and biological properties. These hydrogels incorporate long-range ordered nanocomposite structures within hydrogel network matrixes. Here, the critical design criteria and the state-of-the-art fabrication strategies of nanocomposite hydrogels with highly ordered structures are systemically reviewed. Then, recent progress in applications in the fields of soft actuators, tissue engineering, and sensors is highlighted. The future development and prospective application of highly ordered nanocomposite hydrogels are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Hybrid hydrogels produced by ionizing radiation technique

    International Nuclear Information System (INIS)

    Oliveira, M.J.A.; Amato, V.S.; Lugão, A.B.; Parra, D.F.

    2012-01-01

    The interest in biocompatible hydrogels with particular properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl and 0.5, 1.0, 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopy (FTIR) and swelling in solutions of different pH. The membranes have no toxicity. The nano-clay influences directly the equilibrium swelling. - Highlights: ► Chemical interaction is observed when nanoclay is irradiated in PVAl hybrid hydrogels. ► Osmotic pressure within network promotes the rehydration capacity of the membranes. ► This effect is an important characteristic for hydrogels drug delivery systems.

  6. Peptide based hydrogels for bone tissue engineering

    International Nuclear Information System (INIS)

    Ranny, H.R.; Schneider, J.P.

    2007-01-01

    Peptide hydrogels are potentially ideal scaffolds for tissue repair and regeneration due to their ability to mimic natural extra cellular matrix. The 20 amino acid peptide HPL8 (H2N- VKVKVKVKVDPP TKVKVKVKV-CONH2), has been shown to fold and self-assemble into a rigid hydrogel based on Environmental cues such as pH, salt, and temperature. Due to its environmental responsiveness, hydrogel assembly can be induced by cell culture media, allowing for 3D encapsulation of osteogenic cells. Initially, 20 cultures of MC3T3 cells proved that the hydrogel is nontoxic and sustains cellular attachment in the absence of serum proteins without altering the physical properties of the hydrogel. The cell-material structure relationship in normal and pathological conditions was further investigated by 3D encapsulation. Cell were viable for 3 weeks and grew in clonogenic spheroids. Characterization of the proliferation, differentiation and constitutive expression of various osteoblastic markers was performed using spectrophotometric methods. The well-defined, fibrillar nanostructure of the hydrogel directs the attachment and attachment and growth of osteoblast cells and dictates the mineralization of hydroxyapatite in a manner similar to bone. This study will enable control over the interaction of cellular systems with the peptide hydrogel with designs for biomedical applications of bone repair. (author)

  7. Conversion of Lignocellulosic Bagasse Biomass into Hydrogel

    Directory of Open Access Journals (Sweden)

    Farzaneh Amiri

    2016-11-01

    Full Text Available In recent years, the main objective of developing new hydrogel systems has been to convert biomass into environmentally-friendly hydrogels. Hybrid hydrogels are usually prepared by graft copolymerization of acrylic monomers onto natural polymers or biomass. In this study, sugarcane bagasse was used to prepare semi-synthetic hybrid hydrogels without delignification, which is a costly and timeconsuming process. Sugarcane bagasse as a source of polysaccharide was modified using polymer microgels based on acrylic monomers such as acrylic acid, acrylamide and 2-acrylamido-2-methyl propane sulfonic acid which were prepared through inverse emulsion polymerization. By this process, biomass as a low-value by-product was converted into a valuable semi-synthetic hydrogel. In the following, the effect of latex type¸ the aqueous-to-organic phase ratio in the polymer latex, time and temperature of modification reaction on the swelling capacity of the hybrid hydrogel were evaluated. The chemical reaction between sugarcane bagasse and acrylic latex was carried out during heating of the modified bagasse which led to obtain a semisynthetic hydrogel with 60% natural components and 40% synthetic components. Among the latexes with different structures, poly(AA-NaAA-AM-AMPS was the most suitable polymer latex for the conversion of biomass into hydrogel. The bagasse modified with this latex had a water absorption capacity up to 112 g/g, while the water absorption capacity of primary sugarcane bagasse was only equal to 3.6 g/g. The prepared polymer hydrogels were characterized using Fourier transform infrared spectroscopy (FTIR, dynamic-mechanical thermal analysis (DMTA, thermal gravimetric analysis (TGA, scanning electron microscopy (SEM and determination of the amount of swelling capacity.

  8. A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings

    Directory of Open Access Journals (Sweden)

    Elbadawy A. Kamoun

    2017-05-01

    Full Text Available This review presents the past and current efforts with a brief description on the featured properties of hydrogel membranes fabricated from biopolymers and synthetic ones for wound dressing applications. Many endeavors have been exerted during past ten years for developing new artificial polymeric membranes, which fulfill the demanded conditions for the treatment of skin wounds. This review mainly focuses on representing specifications of ideal polymeric wound dressing membranes, such as crosslinked hydrogels compatible with wound dressing purposes. But as the hydrogels with single component have low mechanical strength, recent trends have offered composite or hybrid hydrogel membranes to achieve the typical wound dressing requirements.

  9. Radiation Synthesis and Application of Carboxymethylated Chitosan Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Young Chang

    2007-08-15

    This research proposal is to investigate radiation effect of carboxymethylated chitosan in order to obtain the crosslinked carboxymethylated chitosan. The application studies on CM-chitosan- based intelligent hydrogels will be tried too. Chitin is the most abundant natural amino polysaccharide and estimated to be produced annually almost as much as cellulose. Chitosan is the deacetylated product of chitin showing the enhanced solubility in dilute acids, further, carboxymethylated chitosan (CM-chitosan) can solve in both acidic and basic physiological media, which might be good candidates as a kind of biomedical materials. Radiation technique is an important method for modification of chitin derivatives. It includes radiation-induced degradation, grafting, and crosslinking. It was found that CM-chitosan degraded in solid state or dilute aqueous solution under irradiation, but crosslinked at paste-like sate when the concentration of CM-chitosan is more than 10%. Both degraded and crosslinked CM-chitosan have antibacterial activity, so it is essential to investigate in detail the radiation effect of CM-chitosan. Study on radiation effect of CM-chitosan in different condition is beneficial to modification of CM-chitosan by irradiation technique. However, little study was reported on radiation crosslinking and application of CM-chitosan. The radiation-closslinked CM-chitosan synthesized from chitosan was characterized by a Fourier transform infrared spectroscopy (FT-IR) analysis. A kinetic swelling in water and the mechanical properties such as a gelation, water absorptivity, and gel strength were also investigated. For the preparation of crosslinked CM-chitosan by using gamma irradiation, the concentration of an aqueous CM-chitosan is above 10wt%. We confirmed that the gel contents was in the range of 15-63%, and when the irradiation dose was increased, the degree of gelation was decreased by disintegration of the CM-chitosan. In conclusion, we developed a new

  10. Radiation Synthesis and Application of Carboxymethylated Chitosan Hydrogels

    International Nuclear Information System (INIS)

    Noh, Young Chang

    2007-08-01

    This research proposal is to investigate radiation effect of carboxymethylated chitosan in order to obtain the crosslinked carboxymethylated chitosan. The application studies on CM-chitosan- based intelligent hydrogels will be tried too. Chitin is the most abundant natural amino polysaccharide and estimated to be produced annually almost as much as cellulose. Chitosan is the deacetylated product of chitin showing the enhanced solubility in dilute acids, further, carboxymethylated chitosan (CM-chitosan) can solve in both acidic and basic physiological media, which might be good candidates as a kind of biomedical materials. Radiation technique is an important method for modification of chitin derivatives. It includes radiation-induced degradation, grafting, and crosslinking. It was found that CM-chitosan degraded in solid state or dilute aqueous solution under irradiation, but crosslinked at paste-like sate when the concentration of CM-chitosan is more than 10%. Both degraded and crosslinked CM-chitosan have antibacterial activity, so it is essential to investigate in detail the radiation effect of CM-chitosan. Study on radiation effect of CM-chitosan in different condition is beneficial to modification of CM-chitosan by irradiation technique. However, little study was reported on radiation crosslinking and application of CM-chitosan. The radiation-closslinked CM-chitosan synthesized from chitosan was characterized by a Fourier transform infrared spectroscopy (FT-IR) analysis. A kinetic swelling in water and the mechanical properties such as a gelation, water absorptivity, and gel strength were also investigated. For the preparation of crosslinked CM-chitosan by using gamma irradiation, the concentration of an aqueous CM-chitosan is above 10wt%. We confirmed that the gel contents was in the range of 15-63%, and when the irradiation dose was increased, the degree of gelation was decreased by disintegration of the CM-chitosan. In conclusion, we developed a new

  11. Fabricating customized hydrogel contact lens

    Science.gov (United States)

    Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

    2016-10-01

    Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

  12. Formulation Changes Affect Material Properties and Cell Behavior in HA-Based Hydrogels

    Directory of Open Access Journals (Sweden)

    Thomas Lawyer

    2012-01-01

    Full Text Available To develop and optimize new scaffold materials for tissue engineering applications, it is important to understand how changes to the scaffold affect the cells that will interact with that scaffold. In this study, we used a hyaluronic acid- (HA- based hydrogel as a synthetic extracellular matrix, containing modified HA (CMHA-S, modified gelatin (Gtn-S, and a crosslinker (PEGda. By varying the concentrations of these components, we were able to change the gelation time, enzymatic degradation, and compressive modulus of the hydrogel. These changes also affected fibroblast spreading within the hydrogels and differentially affected the proliferation and metabolic activity of fibroblasts and mesenchymal stem cells (MSCs. In particular, PEGda concentration had the greatest influence on gelation time, compressive modulus, and cell spreading. MSCs appeared to require a longer period of adjustment to the new microenvironment of the hydrogels than fibroblasts. Fibroblasts were able to proliferate in all formulations over the course of two weeks, but MSCs did not. Metabolic activity changed for each cell type during the two weeks depending on the formulation. These results highlight the importance of determining the effect of matrix composition changes on a particular cell type of interest in order to optimize the formulation for a given application.

  13. Biomimetic Membrane Arrays on Cast Hydrogel Supports

    DEFF Research Database (Denmark)

    Roerdink-Lander, Monique; Ibragimova, Sania; Rein Hansen, Christian

    2011-01-01

    , provides mechanical support but at the cost of small molecule transport through the membrane−support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane−support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE......)/hydrogel sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self......-supporting ETFE/hydrogel sandwiches. We demonstrate how the ETFE/hydrogel sandwich support promotes rapid self-thinning of lipid bilayers suitable for hosting membrane-spanning proteins....

  14. Responsive polyelectrolyte hydrogels and soft matter micromanipulation

    NARCIS (Netherlands)

    Glazer, P.J.

    2013-01-01

    This dissertation describes experimental studies on the mechanisms underlying the dynamic response of polyelectrolyte hydrogels when submitted to an external electric potential. In addition, we explore the possibilities of miniaturization and manipulation of responsive gels and other soft matter

  15. Hydrogels: Lets Thicken the Prebiotic Soup

    Science.gov (United States)

    Dass, A. V.; Georgelin, T.; Kee, T. P.; Brack, A.; Westall, F.

    2017-07-01

    We introduce a new class of material that could be interesting in prebiotic chemistry: The silica hydrogel. Inorganic cells could have provided an alternative mode of compatmentalisation on early earth.

  16. Enzymatic Inverse Opal Hydrogel Particles for Biocatalyst.

    Science.gov (United States)

    Wang, Huan; Gu, Hongcheng; Chen, Zhuoyue; Shang, Luoran; Zhao, Ze; Gu, Zhongze; Zhao, Yuanjin

    2017-04-19

    Enzymatic carriers have a demonstrated value for chemical reactions and industrial applications. Here, we present a novel kind of inverse opal hydrogel particles as the enzymatic carriers. The particles were negatively replicated from spherical colloidal crystal templates by using magnetic nanoparticles tagged acrylamide hydrogel. Thus, they were endowed with the features of monodispersity, small volume, complete penetrating structure, and controllable motion, which are all beneficial for improving the efficiency of biocatalysis. In addition, due to the ordered porous nanostructure, the inverse opal hydrogel particles were imparted with unique photonic band gaps (PBGs) and vivid structural colors for encoding varieties of immobilized enzymes and for constructing a multienzymes biocatalysis system. These features of the inverse opal hydrogel particles indicate that they are ideal enzymatic carriers for biocatalysis.

  17. Radiochromic leuco dye micelle hydrogels: I. Initial investigation

    International Nuclear Information System (INIS)

    Jordan, Kevin; Avvakumov, Nikita

    2009-01-01

    This investigation reports the use of surfactants and colorless leuco triarylmethane dyes to form a new class of radiochromic micelle hydrogels for three-dimensional (3D) water-equivalent dosimetry. Gelatin gel samples with several surfactants and leuco dyes were prepared and evaluated for optical transparency, dose sensitivity and diffusion rates. The addition of Triton X-100, a non-ionic surfactant, at levels exceeding the critical micelle concentration provides a transparent hydrogel in which the water insoluble leuco Malachite Green (LMG) can dissolve. During irradiation, the LMG dye precursor converts to Malachite Green (MG + ). The most sensitive reported LMG gel formulation contains 0.3 mM LMG leuco dye, 16 mM trichloroacetic acid, 7 mM Triton X-100 and 4% w/w gelatin. A diffusion coefficient of 0.14 mm 2 h -1 was determined for MG + in this gel by fitting the time-dependent degradation of the transmission profile after irradiating half of the sample. The diffusion rate was three times lower than the standard radiochromic ferrous xylenol-orange (FX) gel. The primary feature of this 3D hydrogel is that it introduces transparent, radiochromic, micelle hydrogels. The radiochromic response to dose is instantaneous and images are stable for several hours. A dosimetric characterization revealed that the dose response is reproducible to within 10% over five separate batches and independent of both energy and dose rate. Uniform pre-irradiation of samples to 5 Gy provided a subsequent near linear response to greater than 110 Gy. LMG gels when read with a fast optical CT scanner can provide full 3D dose distributions in less than 30 min post-irradiation. LMG micelle gels scanned with a 633 nm light source are a promising system for quantitative water- or tissue-equivalent 3D dose verification in the 5-100 Gy dose range. These gels are useful for the scanning of larger volume dosimeters (i.e. >15 cm diameter) since they are easily prepared with inexpensive ingredients

  18. Modeling Alveolar Epithelial Cell Behavior In Spatially Designed Hydrogel Microenvironments

    Science.gov (United States)

    Lewis, Katherine Jean Reeder

    The alveolar epithelium consists of two cell phenotypes, elongated alveolar type I cells (AT1) and rounded alveolar type II cells (ATII), and exists in a complex three-dimensional environment as a polarized cell layer attached to a thin basement membrane and enclosing a roughly spherical lumen. Closely surrounding the alveolar cysts are capillary endothelial cells as well as interstitial pulmonary fibroblasts. Many factors are thought to influence alveolar epithelial cell differentiation during lung development and wound repair, including physical and biochemical signals from the extracellular matrix (ECM), and paracrine signals from the surrounding mesenchyme. In particular, disrupted signaling between the alveolar epithelium and local fibroblasts has been implicated in the progression of several pulmonary diseases. However, given the complexity of alveolar tissue architecture and the multitude of signaling pathways involved, designing appropriate experimental platforms for this biological system has been difficult. In order to isolate key factors regulating cellular behavior, the researcher ideally should have control over biophysical properties of the ECM, as well as the ability to organize multiple cell types within the scaffold. This thesis aimed to develop a 3D synthetic hydrogel platform to control alveolar epithelial cyst formation, which could then be used to explore how extracellular cues influence cell behavior in a tissue-relevant cellular arrangement. To accomplish this, a poly(ethylene glycol) (PEG) hydrogel network containing enzymatically-degradable crosslinks and bioadhesive pendant peptides was employed as a base material for encapsulating primary alveolar epithelial cells. First, an array of microwells of various cross-sectional shapes was photopatterned into a PEG gel containing photo-labile crosslinks, and primary ATII cells were seeded into the wells to examine the role of geometric confinement on differentiation and multicellular arrangement

  19. A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles.

    Science.gov (United States)

    Dai, Juan; Long, Wei; Liang, Zhongping; Wen, Lu; Yang, Fan; Chen, Gang

    2018-01-01

    Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2 b (IFN α-2 b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37 °C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.

  20. Hyaluronic Acid (HA)-Polyethylene glycol (PEG) as injectable hydrogel for intervertebral disc degeneration patients therapy

    Science.gov (United States)

    Putri Kwarta, Cityta; Widiyanti, Prihartini; Siswanto

    2017-05-01

    Chronic Low Back Pain (CLBP) is one health problem that is often encountered in a community. Inject-able hydrogels are the newest way to restore the disc thickness and hydration caused by disc degeneration by means of minimally invasive surgery. Thus, polymers can be combined to improve the characteristic properties of inject-able hydrogels, leading to use of Hyaluronic Acid (a natural polymer) and Polyethylene glycol (PEG) with Horse Radish Peroxide (HRP) cross linker enzymes. The swelling test results, which approaches were the ideal disc values, were sampled with variation of enzyme concentrations of 0.25 µmol/min/mL. The enzyme concentrations were 33.95%. The degradation test proved that the sample degradation increased along with the decrease of the HRP enzyme concentration. The results of the cytotoxicity assay with MTT assay method showed that all samples resulted in the 90% of living cells are not toxic. In vitro injection, models demonstrated that higher concentration of the enzymes was less state of gel which would rupture when released from the agarose gel. The functional group characterization shows the cross linking bonding in sample with enzyme adding. The conclusion of this study is PEG-HA-HRP enzyme are safe polymer composites which have a potential to be applied as an injectable hydrogel for intervertebral disc degeneration.

  1. Use of hydrogels in the planting of industrial wood plantations ...

    African Journals Online (AJOL)

    This article provides an overview of the concepts of post-plant water stress, a review of trials that tested application of hydrogels to forest tree species, and discussion on probable reasons for failure or success in the use of hydrogels. Hydrogels applied in pot trials, under controlled conditions, tended to have a higher ...

  2. Natural fibers for hydrogels production and their applications in agriculture

    Directory of Open Access Journals (Sweden)

    Liliana Serna Cock

    2017-10-01

    Full Text Available This paper presents a review on hydrogels applied to agriculture emphasizing on the use of natural fibers. The objectives were to examine, trends in research addressed to identify natural fibers used in hydrogels development and methods for modifying natural fibers, understand factors which determine the water retention capacity of a hydrogel. Consequently, this paper shows some methodologies used to evaluate the hydrogels efficiency and to collect in tables, relevant information in relation to methods of natural fibers modification and hydrogel synthesis. It was found that previous research focused on hydrogels development processed with biodegradable polymers such as starch, chitosan and modified natural fibers, cross-linked with potassium acrylate and acrylamide, respectively. In addition, current researches aimed to obtaining hydrogels with improved properties, which have allowed a resistance to climatic variations and soil physicochemical changes, such as pH, presence of salts, temperature and composition. In fact, natural fibers such as sugarcane, agave fiber and kapok fiber, modified with maleic anhydride, are an alternative to obtain hydrogels due to an increasing of mechanical properties and chemically active sites. However, the use of natural nanofibers in hydrogels, has been a successful proposal to improve hydrogels mechanical and swelling properties, since they give to material an elasticity and rigidity properties. A hydrogel efficiency applied to soil, is measured throughout properties as swellability, mechanical strength, and soil water retention. It was concluded that hydrogels, are an alternative to the current needs for the agricultural sector.

  3. Co-assembly of chitosan and phospholipids into hybrid hydrogels

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Shekarforoush, Elhamalsadat; Engwer, Christoph

    2016-01-01

    Novel hybrid hydrogels were formed by adding chitosan (Ch) to phospholipids (P) self-assembled particles in lactic acid. The effect of the phospholipid concentration on the hydrogel properties was investigated and was observed to affect the rate of hydrogel formation and viscoelastic properties...

  4. Resilin-like polypeptide-poly(ethylene gylcol) hybrid hydrogels for mechanically-demanding tissue engineering applications

    Science.gov (United States)

    McGann, Christopher Leland

    Technological progress in the life sciences and engineering has combined with important insights in the fields of biology and material science to make possible the development of biological substitutes which aim to restore function to damaged tissue. Numerous biomimetic hydrogels have been developed with the purpose of harnessing the regenerative capacity of cells and tissue through the rational deployment of biological signals. Aided by recombinant DNA technology and protein engineering methods, a new class of hydrogel precursor, the biosynthetic protein polymer, has demonstrated great promise towards the development of highly functional tissue engineering materials. In particular, protein polymers based upon resilin, a natural protein elastomer, have demonstrated outstanding mechanical properties that would have great value in soft tissue applications. This dissertation introduces hybrid hydrogels composed of recombinant resilin-like polypeptides (RLPs) cross-linked with multi-arm PEG macromers. Two different chemical strategies were employed to form RLP-PEG hydrogels: one utilized a Michael-type addition reaction between the thiols of cysteine residues present within the RLP and vinyl sulfone moieties functionalized on a multi-arm PEG macromer; the second system cross-links a norbornene-functionalized RLP with a thiol-functionalized multi-arm PEG macromer via a photoinitiated thiol-ene step polymerization. Oscillatory rheology and tensile testing confirmed the formation of elastic, resilient hydrogels in the RLP-PEG system cross-linked via Michael-type addition. These hydrogels supported the encapsulation and culture of both human aortic adventitial fibroblasts and human mesenchymal stem cells. Additionally, these RLP-PEG hydrogels exhibited phase separation behavior during cross-linking that led to the formation of a heterogeneous microstructure. Degradation could be triggered through incubation with matrix metalloproteinase. Photocross-linking was conferred to

  5. Changes in myopia with low-Dk hydrogel and high-Dk silicone hydrogel extended wear.

    Science.gov (United States)

    Jalbert, Isabelle; Stretton, Serina; Naduvilath, Thomas; Holden, Brien; Keay, Lisa; Sweeney, Deborah

    2004-08-01

    This study compared changes in myopia between wearers of high-oxygen permeability (Dk) silicone hydrogel lenses and low-Dk hydrogel lenses after 1 year of extended wear (EW). Ninety-two adult subjects were randomly assigned to a lens type. Subjective refraction and autokeratometry were performed at baseline and at 6 and 12 months. After 6 months of EW, myopia (spherical equivalent) regressed by 0.18 +/- 0.33 D (p Dk silicone hydrogel group and progressed by -0.23 +/- 0.36 D (p Dk hydrogel group. There were no further changes after 12 months. Previous lens wear history, baseline refractive error, and age and gender did not have an impact on the change in myopia, and only 35% of the variation could be accounted for by changes in corneal curvature and lens type. Soft contact lens type significantly affects the direction of change in myopia during EW. We hypothesize that these changes are driven by pressure-related redistribution of corneal tissue in high-Dk silicone hydrogel lens wearers and by hypoxia-associated corneal thinning in low-Dk hydrogel wearers. More long-term studies are required to confirm whether the effects of high-Dk silicone hydrogel lens wear on myopia are permanent.

  6. Injectable hydrogels for central nervous system therapy

    International Nuclear Information System (INIS)

    Pakulska, Malgosia M; Shoichet, Molly S; Ballios, Brian G

    2012-01-01

    Diseases and injuries of the central nervous system (CNS) including those in the brain, spinal cord and retina are devastating because the CNS has limited intrinsic regenerative capacity and currently available therapies are unable to provide significant functional recovery. Several promising therapies have been identified with the goal of restoring at least some of this lost function and include neuroprotective agents to stop or slow cellular degeneration, neurotrophic factors to stimulate cellular growth, neutralizing molecules to overcome the inhibitory environment at the site of injury, and stem cell transplant strategies to replace lost tissue. The delivery of these therapies to the CNS is a challenge because the blood–brain barrier limits the diffusion of molecules into the brain by traditional oral or intravenous routes. Injectable hydrogels have the capacity to overcome the challenges associated with drug delivery to the CNS, by providing a minimally invasive, localized, void-filling platform for therapeutic use. Small molecule or protein drugs can be distributed throughout the hydrogel which then acts as a depot for their sustained release at the injury site. For cell delivery, the hydrogel can reduce cell aggregation and provide an adhesive matrix for improved cell survival and integration. Additionally, by choosing a biodegradable or bioresorbable hydrogel material, the system will eventually be eliminated from the body. This review discusses both natural and synthetic injectable hydrogel materials that have been used for drug or cell delivery to the CNS including hyaluronan, methylcellulose, chitosan, poly(N-isopropylacrylamide) and Matrigel. (paper)

  7. Surface Friction of Polyacrylamide Hydrogel Particles

    Science.gov (United States)

    Cuccia, Nicholas; Burton, Justin

    Polyacrylamide hydrogel particles have recently become a popular system for modeling low-friction, granular materials near the jamming transition. Because a gel consists of a polymer network filled with solvent, its frictional behavior is often explained using a combination of hydrodynamic lubrication and polymer-surface interactions. As a result, the frictional coefficient can vary between 0.001 and 0.03 depending on several factors such as contact area, sliding velocity, normal force, and the gel surface chemistry. Most tribological measurements of hydrogels utilize two flat surfaces, where the contact area is not well-defined. We have built a custom, low-force tribometer to measure the single-contact frictional properties of spherical hydrogel particles on flat hydrogel surfaces under a variety of measurement conditions. At high velocities (> 1 cm/s), the friction coefficient depends linearly on velocity, but does not tend to zero at zero velocity. We also compare our measurements to solid particles (steel, glass, etc.) on hydrogel surfaces, which exhibit larger frictional forces, and show less dependence on velocity. A physical model for the friction which includes the lubrication layer between the deformed surfaces will be discussed. National Science Foundation Grant No. 1506446.

  8. Effect of gamma radiation on polyvinylpyrrolidone hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, M.J.A.; Vásquez, P.A.S.; Alcântara, M.T.S.; Munhoz, M.M.L.; Lugão, A.B., E-mail: mariajhho@yahoo.com.br, E-mail: pavsalva@ipen.br, E-mail: ablugao@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Polyvinylpyrrolidone (PVP) hydrogels have been investigated as drug delivery matrices for the treatment of wounds, such as cutaneous leishmaniasis, and matrices with silver nanoparticles for chronic wounds and burns. The preparation of such hydrogels can occur by various cross-linking methods, such as gamma, chemical, physical, among others. The most feasible for wound dressings is gamma irradiation from cobalt-60, because gamma irradiation simultaneously promotes crosslinking and sterilization, leaving the wound dressing ready for use. The objective of this work was to investigate the effect on physico- chemical properties of gamma radiation on PVP hydrogel according to the radiation absorbed dose variation. The PVP hydrogels were irradiated with doses of 5, 15, 25, 35, 45, 55, 65, 75 and 95kGy at dose rate of 5 kGy/h and characterized by swelling, thermogravimetric and mechanical analysis. Results shown a favorable dose range window for processing of these hydrogels related to the application. The results showed that mechanical strength was affected at doses starting at 25 kGy. (author)

  9. Effect of gamma radiation on polyvinylpyrrolidone hydrogels

    International Nuclear Information System (INIS)

    Oliveira, M.J.A.; Vásquez, P.A.S.; Alcântara, M.T.S.; Munhoz, M.M.L.; Lugão, A.B.

    2017-01-01

    Polyvinylpyrrolidone (PVP) hydrogels have been investigated as drug delivery matrices for the treatment of wounds, such as cutaneous leishmaniasis, and matrices with silver nanoparticles for chronic wounds and burns. The preparation of such hydrogels can occur by various cross-linking methods, such as gamma, chemical, physical, among others. The most feasible for wound dressings is gamma irradiation from cobalt-60, because gamma irradiation simultaneously promotes crosslinking and sterilization, leaving the wound dressing ready for use. The objective of this work was to investigate the effect on physico- chemical properties of gamma radiation on PVP hydrogel according to the radiation absorbed dose variation. The PVP hydrogels were irradiated with doses of 5, 15, 25, 35, 45, 55, 65, 75 and 95kGy at dose rate of 5 kGy/h and characterized by swelling, thermogravimetric and mechanical analysis. Results shown a favorable dose range window for processing of these hydrogels related to the application. The results showed that mechanical strength was affected at doses starting at 25 kGy. (author)

  10. PVA hydrogel properties for biomedical application.

    Science.gov (United States)

    Jiang, Shan; Liu, Sha; Feng, Wenhao

    2011-10-01

    PVA has been proposed as a promising biomaterial suitable for tissue mimicking, vascular cell culturing and vascular implanting. In this research, a kind of transparent PVA hydrogel has been investigated in order to mimic the creatural soft tissue deformation during mini-invasive surgery with needle intervention, such as brachytherapy. Three kinds of samples with the same composition of 3 g PVA, 17 g de-ionized water, 80 g dimethyl-sulfoxide but different freeze/thaw cycles have been prepared. In order to investigate the structure and properties of polyvinyl alcohol hydrogel, micro-structure, mechanical property and deformation measurement have been conducted. As the SEM image comparison results show, with the increase of freeze/thaw cycles, PVA hydrogel revealed the similar micro-structure to porcine liver tissue. With uniaxial tensile strength test, the above composition with a five freeze/thaw cycle sample resulted in Young's modulus similar to that of porcine liver's property. Through the comparison of needle insertion deformation experiment and the clinical experiment during brachytherapy, results show that the PVA hydrogel had the same deformation property as prostate tissue. These transparent hydrogel phantom materials can be suitable soft tissue substitutes in needle intervention precision or pre-operation planning studies, particularly in the cases of mimicking creatural tissue deformation and analysing video camera images. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Controlled release studies of calcium alginate hydrogels

    International Nuclear Information System (INIS)

    Rendevski, S.; Andonovski, A.; Mahmudi, N.

    2012-01-01

    Controlled release of substances in many cases may be achieved from calcium alginate hydrogels. In this research, the time dependence of the mass of released model substance bovine serum albumin (BSA) from calcium alginate spherical hydrogels of three different types (G/M ratio) have been investigated. The hydrogels were prepared with the drop-wise method of sodium alginate aqueous solutions with concentration of 0.02 g/cm 3 with 0.01 g/cm 3 BSA and a gelling water bath of chitosan in 0.2 M CH 3 COOH/0.4 M CH 3 COONa with added 0.2 M CaCl 2 .The hydrogel structures were characterized by dynamic light scattering and scanning electron microscopy. The controlled release studies were conducted by UV-Vis spectrophotometry of the released medium with p H=7 at 37 °C. The results showed that the model of osmotic pumping is the dominant mechanism of the release. Also, large dependences of the release profile on the homogeneity of the hydrogels were found. (Author)

  12. Magnetic hyaluronate hydrogels: preparation and characterization

    International Nuclear Information System (INIS)

    Tóth, Ildikó Y.; Veress, Gábor; Szekeres, Márta; Illés, Erzsébet; Tombácz, Etelka

    2015-01-01

    A novel soft way of hyaluronate (HyA) based magnetic hydrogel preparation was revealed. Magnetite nanoparticles (MNPs) were prepared by co-precipitation. Since the naked MNPs cannot be dispersed homogenously in HyA-gel, their surface was modified with natural and biocompatible chondroitin-sulfate-A (CSA) to obtain CSA-coated MNPs (CSA@MNPs). The aggregation state of MNPs and that loaded with increasing amount of CSA up to 1 mmol/g was measured by dynamic light scattering at pH~6. Only CSA@MNP with ≥0.2 mmol/g CSA content was suitable for magnetic HyA-gel preparation. Rheological studies showed that the presence of CSA@MNP with up to 2 g/L did not affect the hydrogel's rheological behavior significantly. The results suggest that the HyA-based magnetic hydrogels may be promising formulations for future biomedical applications, e.g. as intra-articular injections in the treatment of osteoarthritis. - Highlights: • Novel hyaluronate(HyA)-based biocompatible magnetic hydrogels were prepared. • Chondroitin-sulfate-A coating is needed to disperse magnetite particles in HyA-gel. • Rheological behavior of hydrogels was independent of the magnetite content (<2 g/L). • Gels remained in stable and homogeneously dispersed state even after 90 days storage. • Magnetic HyA-gels are promising candidates for use as intra-articular injection

  13. Magnetic hyaluronate hydrogels: preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Tóth, Ildikó Y., E-mail: Ildiko.Toth@chem.u-szeged.hu; Veress, Gábor; Szekeres, Márta; Illés, Erzsébet; Tombácz, Etelka, E-mail: tombacz@chem.u-szeged.hu

    2015-04-15

    A novel soft way of hyaluronate (HyA) based magnetic hydrogel preparation was revealed. Magnetite nanoparticles (MNPs) were prepared by co-precipitation. Since the naked MNPs cannot be dispersed homogenously in HyA-gel, their surface was modified with natural and biocompatible chondroitin-sulfate-A (CSA) to obtain CSA-coated MNPs (CSA@MNPs). The aggregation state of MNPs and that loaded with increasing amount of CSA up to 1 mmol/g was measured by dynamic light scattering at pH~6. Only CSA@MNP with ≥0.2 mmol/g CSA content was suitable for magnetic HyA-gel preparation. Rheological studies showed that the presence of CSA@MNP with up to 2 g/L did not affect the hydrogel's rheological behavior significantly. The results suggest that the HyA-based magnetic hydrogels may be promising formulations for future biomedical applications, e.g. as intra-articular injections in the treatment of osteoarthritis. - Highlights: • Novel hyaluronate(HyA)-based biocompatible magnetic hydrogels were prepared. • Chondroitin-sulfate-A coating is needed to disperse magnetite particles in HyA-gel. • Rheological behavior of hydrogels was independent of the magnetite content (<2 g/L). • Gels remained in stable and homogeneously dispersed state even after 90 days storage. • Magnetic HyA-gels are promising candidates for use as intra-articular injection.

  14. Characterization and improvement of PVAl/PVP/PEG hydrogels

    International Nuclear Information System (INIS)

    Oliveira, Maria Jose A.; Parra, Duclerc F.; Almeida, Monise F.; Lugao, Ademar B.

    2009-01-01

    The use of hydrogels matrices for particular drug release applications has been investigated with the synthesis of modified polymeric hydrogel of poly (vinyl alcohol) (PVAl), poly (N-vinyl-2-pyrrolidone) (PVP) and poly (ethylene glycol). They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. In this study it was compared the hydrogels reticulation for irradiation gamma O 2 and N 2 atmosphere. The characterization of the hydrogels was conducted and the toxicity was evaluated. The dried hydrogel was analyzed by differential scanning calorimetry (DSC), thermogravimetry (TGA), swelling and gel determinations. The membranes have no toxicity and gel content revealed the crosslinking degree. (author)

  15. Radiation synthesis and characterization of polyacrylic acid hydrogels

    International Nuclear Information System (INIS)

    Yang Mingcheng; Song Hongyan; Zhu Chengshen; He Suqin

    2007-01-01

    The pH-sensitive polyacrylic acid (PAA) hydrogels were synthesized by gamma-ray irradiation at an ambient temperature. The influences of dose, monomer concentration, cross-linking agent content, pH, and ionic strength on the swelling ratio (SR) of the PAA hydrogels were investigated in detail. The results show that the SR of the hydrogel decreases with an increase in the dose, monomer concentration, and cross-linking agent content. In alkaline solution, the SR of the hydrogels is much higher than that in acid solution. Also, the ionic strength can influence the SR of the hydrogels. The more the concentration, the lower the SR. (authors)

  16. Novel in situ forming, degradable dextran hydrogels by michael addition chemistry: synthesis, rheology, and degradation

    NARCIS (Netherlands)

    Hiemstra, C.; van der Aa, L.J.; Zhong, Zhiyuan; Dijkstra, Pieter J.; Feijen, Jan

    2007-01-01

    Various vinyl sulfone functionalized dextrans (dex-VS) (Mn,dextran = 14K or 31K) with degrees of substitution (DS) ranging from 2 to 22 were conveniently prepared by a one-pot synthesis procedure at room temperature. This procedure involved reaction of a mercaptoalkanoic acid with an excess amount

  17. Production of hydrogel wound dressing by radiation

    International Nuclear Information System (INIS)

    Isobe, Kazuki

    2008-01-01

    It has been thought that making a dry scab helps to cure a wound faster. However, recently a treatment of a wound according to moist healing theory which cure a wound without making a scab is becoming popular. Accordingly, we prepared a highly stable sheet type hydrogel in a short period by radiating electron beam to an aqueous solution of a polymer. The hydrogel is not soluble in water and keeps suitable moist environment for wound healing. Therefore, a hydrogel a wound dressing, Viewgel R in which represents a registered trademark and is referred to Viewgel hereinafter, is developed and released from July of 2004. In this paper we report the process of the development of Viewgel. (author)

  18. Synthesis and characterization of anisotropic magnetic hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichs, Stephan, E-mail: stephan.hinrichs@chemie.uni-hamburg.de; Nun, Nils; Fischer, Birgit, E-mail: birgit.fischer@chemie.uni-hamburg.de

    2017-06-01

    Multiresponsive hydrogels are an interesting new class of materials. They offer the advantage, that they respond to different stimuli like temperature, pH and magnetic fields. By this they can change their properties which makes the hydrogels ideal candidates for many applications in the technical as well as medical field. Here we present the synthesis and characterization of hydrogels - micro- as well as macrogels - which consist of an iron oxide core, varying in phase and morphology, embedded in a thermoresponsive polymer, consisting of poly N-isopropylacrylamide. By using dynamic light scattering we investigated the thermoresponsive properties. In addition we were able to follow the formation of the macrogel by monitoring the shear viscosity.

  19. Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Szu-Hsien [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Tsao, Ching-Ting [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Epithelial Biology Laboratory/Transgenic Mice Core-Laboratory, Department of Anatomy, Chang Gung University, Taoyuan 33302, Taiwan (China); Chang, Chih-Hao [Department of Orthopedics, National Taiwan University Hospital, Taiwan (China); National Taiwan University College of Medicine, No. 1, Jen-Ai Road, Taipei City 10018, Taiwan (China); Lai, Yi-Ting [Department of Chemical Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Wu, Ming-Fung [Animal Medicine Center, College of Medicine, National Taiwan University, No. 1, Jen-Ai Road, Taipei City 10018, Taiwan (China); Chuang, Ching-Nan [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Chou, Hung-Chia [Department of Chemical Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China); Wang, Chih-Kuang, E-mail: ckwang@kmu.edu.tw [Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan (China); Hsieh, Kuo-Haung, E-mail: khhsieh@ntu.edu.tw [Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei City 10617, Taiwan (China)

    2013-07-01

    Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m{sup 2}/day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing. Highlights: ► Mouse angiogenesis study on reinforced poly(ethylene glycol)-chitosan (RPC) ► Water vapor transmission rate of about 2000 g/m{sup 2}/day is characteristic of RPC. ► RPC suppressed inflammatory cells and accelerated fibroblast proliferation. ► RPC composed of 1000-RP10C90 can be used as a biomaterial for wound dressing.

  20. Assessment of reinforced poly(ethylene glycol) chitosan hydrogels as dressings in a mouse skin wound defect model

    International Nuclear Information System (INIS)

    Chen, Szu-Hsien; Tsao, Ching-Ting; Chang, Chih-Hao; Lai, Yi-Ting; Wu, Ming-Fung; Chuang, Ching-Nan; Chou, Hung-Chia; Wang, Chih-Kuang; Hsieh, Kuo-Haung

    2013-01-01

    Wound dressings of chitosan are biocompatible, biodegradable, antibacterial and hemostatic biomaterials. However, applications for chitosan are limited due to its poor mechanical properties. Here, we conducted an in vivo mouse angiogenesis study on reinforced poly(ethylene glycol) (PEG)-chitosan (RPC) hydrogels. RPC hydrogels were formed by cross-linking chitosan with PEGs of different molecular weights at various PEG to chitosan ratios in our previous paper. These dressings can keep the wound moist, had good gas exchange capacity, and was capable of absorbing or removing the wound exudate. We examined the ability of these RPC hydrogels and neat chitosan to heal small cuts and full-thickness skin defects on the backs of male Balb/c mice. Histological examination revealed that chitosan suppressed the infiltration of inflammatory cells and accelerated fibroblast proliferation, while PEG enhanced epithelial migration. The RPC hydrogels promoted wound healing in the small cuts and full layer wounds. The optimal RPC hydrogel had a swelling ratio of 100% and a water vapor transmission rate (WVTR) of about 2000 g/m 2 /day. In addition, they possess good mechanical property and appropriate degradation rates. Thus, the optimal RPC hydrogel formulation functioned effectively as a wound dressing and promoted wound healing. Highlights: ► Mouse angiogenesis study on reinforced poly(ethylene glycol)-chitosan (RPC) ► Water vapor transmission rate of about 2000 g/m 2 /day is characteristic of RPC. ► RPC suppressed inflammatory cells and accelerated fibroblast proliferation. ► RPC composed of 1000-RP10C90 can be used as a biomaterial for wound dressing

  1. Gradient Material Strategies for Hydrogel Optimization in Tissue Engineering Applications

    Science.gov (United States)

    2018-01-01

    Although a number of combinatorial/high-throughput approaches have been developed for biomaterial hydrogel optimization, a gradient sample approach is particularly well suited to identify hydrogel property thresholds that alter cellular behavior in response to interacting with the hydrogel due to reduced variation in material preparation and the ability to screen biological response over a range instead of discrete samples each containing only one condition. This review highlights recent work on cell–hydrogel interactions using a gradient material sample approach. Fabrication strategies for composition, material and mechanical property, and bioactive signaling gradient hydrogels that can be used to examine cell–hydrogel interactions will be discussed. The effects of gradients in hydrogel samples on cellular adhesion, migration, proliferation, and differentiation will then be examined, providing an assessment of the current state of the field and the potential of wider use of the gradient sample approach to accelerate our understanding of matrices on cellular behavior. PMID:29485612

  2. pH-Sensitive Hydrogel for Micro-Fluidic Valve

    Directory of Open Access Journals (Sweden)

    Zhengzhi Yang

    2012-07-01

    Full Text Available The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.

  3. 3D-Printable Bioactivated Nanocellulose-Alginate Hydrogels.

    Science.gov (United States)

    Leppiniemi, Jenni; Lahtinen, Panu; Paajanen, Antti; Mahlberg, Riitta; Metsä-Kortelainen, Sini; Pinomaa, Tatu; Pajari, Heikki; Vikholm-Lundin, Inger; Pursula, Pekka; Hytönen, Vesa P

    2017-07-05

    We describe herein a nanocellulose-alginate hydrogel suitable for 3D printing. The composition of the hydrogel was optimized based on material characterization methods and 3D printing experiments, and its behavior during the printing process was studied using computational fluid dynamics simulations. The hydrogel was biofunctionalized by the covalent coupling of an enhanced avidin protein to the cellulose nanofibrils. Ionic cross-linking of the hydrogel using calcium ions improved the performance of the material. The resulting hydrogel is suitable for 3D printing, its mechanical properties indicate good tissue compatibility, and the hydrogel absorbs water in moist conditions, suggesting potential in applications such as wound dressings. The biofunctionalization potential was shown by attaching a biotinylated fluorescent protein and a biotinylated fluorescent small molecule via avidin and monitoring the material using confocal microscopy. The 3D-printable bioactivated nanocellulose-alginate hydrogel offers a platform for the development of biomedical devices, wearable sensors, and drug-releasing materials.

  4. Thermoresponsive chitosan-agarose hydrogel for skin regeneration.

    Science.gov (United States)

    Miguel, Sónia P; Ribeiro, Maximiano P; Brancal, Hugo; Coutinho, Paula; Correia, Ilídio J

    2014-10-13

    Healing enhancement and pain control are critical issues on wound management. So far, different wound dressings have been developed. Among them, hydrogels are the most applied. Herein, a thermoresponsive hydrogel was produced using chitosan (deacetylation degree 95%) and agarose. Hydrogel bactericidal activity, biocompatibility, morphology, porosity and wettability were characterized by confocal microscopy, MTS assay and SEM. The performance of the hydrogel in the wound healing process was evaluated through in vivo assays, during 21 days. The attained results revealed that hydrogel has a pore size (90-400 μm) compatible with cellular internalization and proliferation. A bactericidal activity was observed for hydrogels containing more than 188 μg/mL of chitosan. The improved healing and the lack of a reactive or a granulomatous inflammatory reaction in skin lesions treated with hydrogel demonstrate its suitability to be used in a near future as a wound dressing. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Development of hydrogels composites for potential use as biomaterials

    International Nuclear Information System (INIS)

    Silva, Gabriela T. da; Alves, Natali O.; Schulz, Gracelie A.S.; Fajardo, Andre R.

    2015-01-01

    Hydrogels, three-dimensional polymer networks that can absorb and retain impressive amounts of liquid, have shown a remarkable evolution in the past years. Since their first description, the hydrogels have replaced their inert characteristic by smart properties, which help enlarging the range of applicability of such soft materials in different fields. Hydrogels had been prepared from various polymers (including synthetic or natural or both), which allows obtaining materials with unique and desirable properties. This work deals with the preparation of hydrogels and hydrogel composites based on a synthetic/natural hybrid polymer network filled with bovine bone powder, which is composed mainly by hydroxyapatite (as inorganic phase) and collagen (as organic phase). The resulting materials were characterized by DRX, FTIR and TGA analyses. Additionally, water uptake capacity was estimated for both hydrogels and hydrogels composites samples by swelling assays. (author)

  6. Photo-cross-linked PLA-PEO-PLA hydrogels from self-assembled physical networks: mechanical properties and influence of assumed constitutive relationships.

    Science.gov (United States)

    Sanabria-DeLong, Naomi; Crosby, Alfred J; Tew, Gregory N

    2008-10-01

    Poly(lactide)-block-poly(ethylene oxide)-block-poly(lactide) (PLA-PEO-PLA) triblock copolymers are known to form physical hydrogels in water as a result of the polymer's amphiphilicity. Their mechanical properties, biocompatibility, and biodegradability have made them attractive for use as soft tissue scaffolds. However, the network junction points are not covalently cross-linked, and in a highly aqueous environment these hydrogels adsorb more water, transform from gel to sol, and lose the designed mechanical properties. In this article, a hydrogel was formed by the use of a novel two-step approach. In the first step, the end-functionalized PLA-PEO-PLA triblock was self-assembled into a physical hydrogel through hydrophobic micelle network junctions, and in the second step, this self-assembled physical network structure was locked into place by photo-cross-linking the terminal acrylate groups. In contrast with physical hydrogels, the photo-cross-linked gels remained intact in phosphate-buffered solution at body temperature. The swelling, degradation, and mechanical properties were characterized, and they demonstrated an extended degradation time (approximately 65 days), an exponential decrease in modulus with degradation time, and a tunable shear modulus (1.6-133 kPa). We also discuss the various constitutive relationships (Hookean, neo-Hookean, and Mooney-Rivlin) that can be used to describe the stress-strain behavior of these hydrogels. The chosen model and assumptions used for data fitting influenced the obtained modulus values by as much as a factor of 3.5, which demonstrates the importance of clearly stating one's data fitting parameters so that accurate comparisons can be made within the literature.

  7. Development of a radiochromic ferric oligomer hydrogel

    International Nuclear Information System (INIS)

    Jordan, Kevin; Sekimoto, Masaya

    2010-01-01

    Ferrous gelatin hydrogels were prepared by using sulphuric acid concentrations lower than required to maintain radiation induced ferric ions fully hydrated. The ferric hydroxyl species that are produced following irradiation exhibit a radiochromic response that can be probed with blue light. The dose distribution shapes were stable in time, indicating no long term diffusion. An over response to dose gradients was observed both in one centimeter cuvette samples and litre volumes probed with optical cone beam CT. This ferrous hydrogel may represent a model system for studying iron radiochemistry in biological systems.

  8. Hydrogel based QCM aptasensor for detection of avian influenza virus.

    Science.gov (United States)

    Wang, Ronghui; Li, Yanbin

    2013-04-15

    The objective of this study was to develop a quartz crystal microbalance (QCM) aptasensor based on ssDNA crosslinked polymeric hydrogel for rapid, sensitive and specific detection of avian influenza virus (AIV) H5N1. A selected aptamer with high affinity and specificity against AIV H5N1 surface protein was used, and hybridization between the aptamer and ssDNA formed the crosslinker in the polymer hydrogel. The aptamer hydrogel was immobilized on the gold surface of QCM sensor using a self-assembled monolayer method. The hydrogel remained in the state of shrink if no H5N1 virus was present in the sample because of the crosslinking between the aptamer and ssDNA in the polymer network. When it exposed to target virus, the binding reaction between the aptamer and H5N1 virus caused the dissolution of the linkage between the aptamer and ssDNA, resulting in the abrupt swelling of the hydrogel. The swollen hydrogel was monitored by the QCM sensor in terms of decreased frequency. Three polymeric hydrogels with different ratio (100:1 hydrogel I, 10:1 hydrogel II, 1:1 hydrogel III) of acrylamide and the aptamer monomer were synthesized, respectively, and then were used as the QCM sensor coating material. The results showed that the developed hydrogel QCM aptasensor was capable of detecting target H5N1 virus, and among the three developed aptamer hydrogels, hydrogel III coated QCM aptasensor achieved the highest sensitivity with the detection limit of 0.0128 HAU (HA unit). The total detection time from sampling to detection was only 30 min. In comparison with the anti-H5 antibody coated QCM immunosensor, the hydrogel QCM aptasensor lowered the detection limit and reduced the detection time. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Engineered 3D-scaffolds of photocrosslinked chitosan-gelatin hydrogel hybrids for chronic wound dressings and regeneration.

    Science.gov (United States)

    Carvalho, Isadora C; Mansur, Herman S

    2017-09-01

    Wound repair is one of the most complex biological processes in human life. To date, no ideal biomaterial solution has been identified, which that encompasses all functions and properties of real skin tissue. Thus, this study focused on the synthesis of new biocompatible hybrid hydrogel scaffolds based on methacrylate-functionalized high molecular mass chitosan with gelatin-A photocrosslinked with UV radiation to tailor matrix network properties. These hybrid hydrogels were produced via freeze-drying and were extensively characterized by swelling and degradation measurements, Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM-EDS), and micro-computed tomography (micro-CT). The results demonstrated that hydrogels were produced with broadly designed swelling degrees typically ranging from 500% to 2000%, which were significantly dependent on the relative concentration of polymers and irradiation time for crosslinking. Analogously, degradation was reduced with increased photocrosslinking of the network. Moreover, insights into the mechanism of photochemical crosslinking were suggested based on FTIR and UV-Vis analyses of the characteristic functional groups involved in the reactions. SEM analysis associated with micro-CT imaging of the hybrid scaffolds showed uniformly interconnected 3D porous structures, with architectural features affected by the crosslinking of the network. These hydrogels were biocompatible, with live cell viability responses of human embryonic kidney (HEK293T) cells being above 95%. Hence, novel hybrid hydrogels were designed and produced with tunable properties through photocrosslinking and with a biocompatible response suitable for use in wound dressing and skin tissue repair applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. The synthesis of hydrogels with controlled distribution of polymer brushes in hydrogel network

    Energy Technology Data Exchange (ETDEWEB)

    Sun, YuWei; Zhou, Chao; Zhang, AoKai; Xu, LiQun; Yao, Fang [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China); Cen, Lian, E-mail: cenlian@hotmail.com [National Tissue Engineering Center of China, No.68, East Jiang Chuan Road, Shanghai, 200241 (China); School of Chemical Engineering, East China University of Science and Technology, No.130, Mei Long Road, Shanghai, 200237 (China); Fu, Guo-Dong, E-mail: fu7352@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China)

    2014-11-30

    Highlights: • Many biological tissues are 3-dimensionally asymmetric in structure and properties, it would be desirable if hydrogels could bear such structural similarity with specialized surface and bulk properties. Moreover, gradual but continuous variation in spatial structural and property is also a common phenomenon in biological tissues, such as interfaces between bone and tendon, or between bone and cartilage. Hence, the development of a method to introduce well-defined functional polymer brushes on PEG hydrogels, especially with precisely controlled spatial structure in 3-dimensions, would impart the hydrogels with special functionalities and wider applications. Poly(ethylene glycol) (PEG) hydrogels with 3-dimensionally controlled well-defined poly(N-isopropylacrylamide) (poly(NIPAAm)) brushes were prepared by combined copper(I)-catalyzed azide-alkyne cycloaddition (“Click Chemistry”) and atom transfer radical polymerization (ATRP). The resulting hydrogels were presented as representatives with their detailed synthesis routes and characterization. H{sub PEG}-S-poly(NIPAAm) is a hydrogel with poly(NIPAAm) brushes mainly grafted on surface, whereas H{sub PEG}-G-poly(NIPAAm) has a gradiently decreased poly(NIPAAm) brushes in their chain length from surface to inside. On the other hand, poly(NIPAAm) brushes in H{sub PEG}-U-poly(NIPAAm) are uniformly dispersed throughout the whole hydrogel network. Successful preparation of H{sub PEG}-S-poly(NIPAAm), H{sub PEG}-G-poly(NIPAAm) and H{sub PEG}-U-poly(NIPAAm) were ascertained by X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. Hence, the flexibility and controllability of the synthetic strategy in varying the distribution of polymer brushes and hydrogel surface properties was demonstrated. Hydrogels with tunable and well-defined 3-dimensional poly(NIPAAm) polymer brushes could be tailor-designed to find potential applications in smart devices or skin dressing, such as for diabetics

  11. Biocompatible Porous Polyester-Ether Hydrogel Scaffolds with Cross-Linker Mediated Biodegradation and Mechanical Properties for Tissue Augmentation

    Directory of Open Access Journals (Sweden)

    Berkay Ozcelik

    2018-02-01

    Full Text Available Porous polyester-ether hydrogel scaffolds (PEHs were fabricated using acid chloride/alcohol chemistry and a salt templating approach. The PEHs were produced from readily available and cheap commercial reagents via the reaction of hydroxyl terminated poly(ethylene glycol (PEG derivatives with sebacoyl, succinyl, or trimesoyl chloride to afford ester cross-links between the PEG chains. Through variation of the acid chloride cross-linkers used in the synthesis and the incorporation of a hydrophobic modifier (poly(caprolactone (PCL, it was possible to tune the degradation rates and mechanical properties of the resulting hydrogels. Several of the hydrogel formulations displayed exceptional mechanical properties, remaining elastic without fracture at compressive strains of up to 80%, whilst still displaying degradation over a period of weeks to months. A subcutaneous rat model was used to study the scaffolds in vivo and revealed that the PEHs were infiltrated with well vascularised tissue within two weeks and had undergone significant degradation in 16 weeks without any signs of toxicity. Histological evaluation for immune responses revealed that the PEHs incite only a minor inflammatory response that is reduced over 16 weeks with no evidence of adverse effects.

  12. Bacterial adhesion to conventional hydrogel and new silicone-hydrogel contact lens materials.

    Science.gov (United States)

    Kodjikian, Laurent; Casoli-Bergeron, Emmanuelle; Malet, Florence; Janin-Manificat, Hélène; Freney, Jean; Burillon, Carole; Colin, Joseph; Steghens, Jean-Paul

    2008-02-01

    As bacterial adhesion to contact lenses may contribute to the pathogenesis of keratitis, the aim of our study was to investigate in vitro adhesion of clinically relevant bacteria to conventional hydrogel (standard HEMA) and silicone-hydrogel contact lenses using a bioluminescent ATP assay. Four types of unworn contact lenses (Etafilcon A, Galyfilcon A, Balafilcon A, Lotrafilcon B) were incubated with Staphylococcus epidermidis (two different strains) and Pseudomonas aeruginosa suspended in phosphate buffered saline (PBS). Lenses were placed with the posterior surface facing up and were incubated in the bacterial suspension for 4 hours at 37 degrees C. Bacterial binding was then measured and studied by bioluminescent ATP assay. Six replicate experiments were performed for each lens and strain. Adhesion of all species of bacteria to standard HEMA contact lenses (Etafilcon A) was found to be significantly lower than that of three types of silicone-hydrogel contact lenses, whereas Lotrafilcon B material showed the highest level of bacterial binding. Differences between species in the overall level of adhesion to the different types of contact lenses were observed. Adhesion of P. aeruginosa was typically at least 20 times greater than that observed with both S. epidermidis strains. Conventional hydrogel contact lenses exhibit significantly lower bacterial adhesion in vitro than silicone-hydrogel ones. This could be due to the greater hydrophobicity but also to the higher oxygen transmissibility of silicone-hydrogel lenses.

  13. Urease immobilized polymer hydrogel: Long-term stability and enhancement of enzymatic activity.

    Science.gov (United States)

    Kutcherlapati, S N Raju; Yeole, Niranjan; Jana, Tushar

    2016-02-01

    A method has been developed in which an enzyme namely urease was immobilized inside hydrogel matrix to study the stability and enzymatic activity in room temperature (∼27-30°C). This urease coupled hydrogel (UCG) was obtained by amine-acid coupling reaction and this procedure is such that it ensured the wider opening of mobile flap of enzyme active site. A systematic comparison of urea-urease assay and the detailed kinetic data clearly revealed that the urease shows activity for more than a month when stored at ∼27-30°C in case of UCG whereas it becomes inactive in case of free urease (enzyme in buffer solution). The aqueous microenvironment inside the hydrogel, unusual morphological features and thermal behaviour were believed to be the reasons for unexpected behaviour. UCG displayed enzyme activity at basic pH and up to 60°C. UCG showed significant enhancement in activity against thermal degradation compared to free urease. In summary, this method is a suitable process to stabilize the biomacromolecules in standard room temperature for many practical uses. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Exploration of alginate hydrogel/nano zinc oxide composite bandages for infected wounds

    Directory of Open Access Journals (Sweden)

    Mohandas A

    2015-10-01

    Full Text Available Annapoorna Mohandas,* Sudheesh Kumar PT,* Biswas Raja, Vinoth-Kumar Lakshmanan, Rangasamy Jayakumar Amrita Centre for Nanosciences and Molecular Medicine, Amrita Institute of Medical Sciences and Research Centre, Amrita Vishwa Vidyapeetham University, Kochi, India *These authors contributed equally to this work Abstract: Alginate hydrogel/zinc oxide nanoparticles (nZnO composite bandage was developed by freeze-dry method from the mixture of nZnO and alginate hydrogel. The developed composite bandage was porous with porosity at a range of 60%–70%. The swelling ratios of the bandages decreased with increasing concentrations of nZnO. The composite bandages with nZnO incorporation showed controlled degradation profile and faster blood clotting ability when compared to the KALTOSTAT® and control bandages without nZnO. The prepared composite bandages exhibited excellent antimicrobial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and methicillin resistant S. aureus (MRSA. Cytocompatibility evaluation of the prepared composite bandages done on human dermal fibroblast cells by Alamar assay and infiltration studies proved that the bandages have a non-toxic nature at lower concentrations of nZnO whereas slight reduction in viability was seen with increasing nZnO concentrations. The qualitative analysis of ex-vivo re-epithelialization on porcine skin revealed keratinocyte infiltration toward wound area for nZnO alginate bandages. Keywords: alginate, hydrogel, ZnO nanoparticle, hemostatic, antimicrobial activity, wound healing

  15. Glycosaminoglycan-based hydrogels to modulate heterocellular communication in in vitro angiogenesis models

    Science.gov (United States)

    Chwalek, Karolina; Tsurkan, Mikhail V.; Freudenberg, Uwe; Werner, Carsten

    2014-03-01

    Angiogenesis, the outgrowth of blood vessels, is crucial in development, disease and regeneration. Studying angiogenesis in vitro remains challenging because the capillary morphogenesis of endothelial cells (ECs) is controlled by multiple exogenous signals. Therefore, a set of in situ-forming starPEG-heparin hydrogels was used to identify matrix parameters and cellular interactions that best support EC morphogenesis. We showed that a particular type of soft, matrix metalloproteinase-degradable hydrogel containing covalently bound integrin ligands and reversibly conjugated pro-angiogenic growth factors could boost the development of highly branched, interconnected, and lumenized endothelial capillary networks. Using these effective matrix conditions, 3D heterocellular interactions of ECs with different mural cells were demonstrated that enabled EC network modulation and maintenance of stable vascular capillaries over periods of about one month in vitro. The approach was also shown to permit in vitro tumor vascularization experiments with unprecedented levels of control over both ECs and tumor cells. In total, the introduced 3D hydrogel co-culture system could offer unique options for dissecting and adjusting biochemical, biophysical, and cell-cell triggers in tissue-related vascularization models.

  16. Kinetic investigation and lifetime prediction of Cs-NIPAM-MBA-based thermo-responsive hydrogels.

    Science.gov (United States)

    Othman, Muhammad Bisyrul Hafi; Khan, Abbas; Ahmad, Zulkifli; Zakaria, Muhammad Razlan; Ullah, Faheem; Akil, Hazizan Md

    2016-01-20

    This study attempted to clarify the influence of a cross-linker, N,N-methylenebisacrylamide (MBA), and N-isopropylacrylamide (NIPAM) on the non-isothermal kinetic degradation, solid state and lifetime of hydrogels using the Flynn-Wall-Ozawa (F-W-O), Kissinger, and Coats-Redfern (C-Red) methods. The series of dual-responsive Cs-PNIPAM-MBA microgels were synthesized by soapless-emulsion free radical copolymerization in an aqueous medium at 70 °C. The thermal properties were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC) under nitrogen atmosphere. The apparent activation energy using the chosen Flynn-Wall-Ozawa and Kissinger methods showed that they fitted each other. Meanwhile, the type of solid state mechanism was determined using the Coats-Redfern method proposed for F1 (pure Cs) and F2 (Cs-PNIPAM-MBA hydrogel series) types, which comprise random nucleation with one nucleus reacting on individual particles, and random nucleation with two nuclei reacting on individual particles, respectively. On average, a higher Ea was attributed to the greater cross-linking density of the Cs hydrogel. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Hydrogels in a historical perspective: From simple networks to smart materials

    NARCIS (Netherlands)

    Buwalda, S.J.; Boere, K.W.M.; Dijkstra, Pieter J.; Feijen, Jan; Vermonden, T.; Hennink, W.E.

    2014-01-01

    Over the past decades, significant progress has been made in the field of hydrogels as functional biomaterials. Biomedical application of hydrogels was initially hindered by the toxicity of crosslinking agents and limitations of hydrogel formation under physiological conditions. Emerging knowledge

  18. Hydrogels in a historical perspective : From simple networks to smart materials

    NARCIS (Netherlands)

    Buwalda, Sytze J.|info:eu-repo/dai/nl/339146850; Boere, Kristel W M|info:eu-repo/dai/nl/338018093; Dijkstra, Pieter J.; Feijen, Jan; Vermonden, Tina|info:eu-repo/dai/nl/275124517; Hennink, Wim E.|info:eu-repo/dai/nl/070880409

    2014-01-01

    Over the past decades, significant progress has been made in the field of hydrogels as functional biomaterials. Biomedical application of hydrogels was initially hindered by the toxicity of crosslinking agents and limitations of hydrogel formation under physiological conditions. Emerging knowledge

  19. Formulation and release of alaptide from cellulose-based hydrogels

    Directory of Open Access Journals (Sweden)

    Zbyněk Sklenář

    2012-01-01

    Full Text Available The modern drug alaptide, synthetic dipeptide, shows regenerative effects and effects on the epitelisation process. A commercial product consisting of 1% alaptide hydrophilic cream is authorised for use in veterinary practice. This study focuses on the formulation of alaptide into semi-synthetic polymer-based hydrogels. The aim of the present study is to prepare hydrogels and to evaluate the liberation of alaptide from hydrogels. The hydrogels were prepared on the basis of three gel-producing substances: methylcellulose, hydroxyethylcellulose and hydroxypropylcellulose. To enhance the drug release from hydrogel humectants, glycerol, propylene glycol and ethanol in various concentrations were evaluated. The permeation of the alaptide from gels into the acceptor solution was evaluated with the use of the permeable membrane neprophane. The amount of drug released from prepared hydrogels was determined spectrophotometrically. Hydrogels with optimal alaptide liberation properties were subjected to the study of rheological properties in the next phase. The optimal composition of hydrogel as established in this study was 1% alaptide + 3% hydroxyethylcellulose with the addition of 10% glycerol as humectant. Due to the advantageous properties of hydrogels in wounds, alaptide could be incorporated into a hydrogel base for use in veterinary medicine.

  20. Methacrylate hydrogels reinforced with bacterial cellulose

    Czech Academy of Sciences Publication Activity Database

    Hobzová, Radka; Dušková-Smrčková, Miroslava; Michálek, Jiří; Karpushkin, Evgeny; Gatenholm, P.

    2012-01-01

    Roč. 61, č. 7 (2012), s. 1193-1201 ISSN 0959-8103 R&D Projects: GA AV ČR KJB400500902 Institutional research plan: CEZ:AV0Z40500505 Keywords : bacterial cellulose * methacrylate hydrogel * composite Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.125, year: 2012

  1. Polymer hydrogels as optimized delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Jorge G.S.; Varca, Gustavo H.C.; Ferraz, Caroline C.; Garrido, Gabriela P.; Diniz, Bruna M.; Carvalho, Vinicius S.; Lugao, Ademar B., E-mail: jorgegabriel@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Hydrogels are formed by polymers capable of absorbing large quantities of water. They consist of one or more three-dimensionally structured polymer networks formed by macromolecular chains linked by covalent bonds-crosslinks - and physical interactions. The application of hydrogels, has been widely studied. Biodegradable synthetic or natural polymers such as chitosan, starch and poly-lactic-co-glycolic acid, have properties that allow the development of biodegradable systems for drug and nutraceutics delivery. This study aimed to develop polymeric hydrogels based on polyvinyl alcohol, polyacrylamide and polyvinylpyrrolidone using ionizing radiation in order to develop hydrogels for improved loading and release of compounds. Polymer solutions were solubilized in water and poured into thermoformed packages. After sealing, the material was subjected to γ-irradiation at 25kGy. The samples were assayed by means of mechanical properties, gel fraction and swelling degree. Nanostructure characterization was performed using Flory's equation to determine crosslinking density. The systems developed showed swelling degree and adequate mechanical resistance. The nanostructure evaluation showed different results for each system demonstrating the need of choosing the polymer based on the specific properties of each material. (author)

  2. Synthesis and characterization of carboxymethyl chitosan hydrogel ...

    Indian Academy of Sciences (India)

    Local application of drug delivery system could be very. ∗. Author for ... In this study, chitosan was modified by car- ... C18 (250 × 4·6mm ID, 5 μm pore size) column with auto .... Some amount of drug was lost during washing of hydrogels.

  3. Polymer hydrogels as optimized delivery systems

    International Nuclear Information System (INIS)

    Batista, Jorge G.S.; Varca, Gustavo H.C.; Ferraz, Caroline C.; Garrido, Gabriela P.; Diniz, Bruna M.; Carvalho, Vinicius S.; Lugao, Ademar B.

    2013-01-01

    Hydrogels are formed by polymers capable of absorbing large quantities of water. They consist of one or more three-dimensionally structured polymer networks formed by macromolecular chains linked by covalent bonds-crosslinks - and physical interactions. The application of hydrogels, has been widely studied. Biodegradable synthetic or natural polymers such as chitosan, starch and poly-lactic-co-glycolic acid, have properties that allow the development of biodegradable systems for drug and nutraceutics delivery. This study aimed to develop polymeric hydrogels based on polyvinyl alcohol, polyacrylamide and polyvinylpyrrolidone using ionizing radiation in order to develop hydrogels for improved loading and release of compounds. Polymer solutions were solubilized in water and poured into thermoformed packages. After sealing, the material was subjected to γ-irradiation at 25kGy. The samples were assayed by means of mechanical properties, gel fraction and swelling degree. Nanostructure characterization was performed using Flory's equation to determine crosslinking density. The systems developed showed swelling degree and adequate mechanical resistance. The nanostructure evaluation showed different results for each system demonstrating the need of choosing the polymer based on the specific properties of each material. (author)

  4. Dual responsive supramolecular hydrogel with electrochemical activity.

    Science.gov (United States)

    Du, Ping; Liu, Jianghua; Chen, Guosong; Jiang, Ming

    2011-08-02

    Supramolecular materials with reversible responsiveness to environmental changes are of particular research interest in recent years. Inclusion complexation between cyclodextrin (CD) and ferrocene (Fc) is well-known and extensively studied because of its reversible association-dissociation controlled by the redox state of Fc. Although there are quite a few reported nanoscale materials incorporating this host-guest pair, polymeric hydrogels with electrochemical activity based on this interactive pair are still rare. Taking advantage of our previous reported hybrid inclusion complex (HIC) hydrogel structure, a new Fc-HIC was designed and obtained with β-CD-modified quantum dots as the core and Fc-ended diblock co-polymer p(DMA-b-NIPAM) as the shell, to achieve an electrochemically active hydrogel at elevated temperatures. Considering the two independent cross-linking strategies in the network structure, i.e., the interchain aggregation of pNIPAM and inclusion complexation between CD and Fc on the surface of the quantum dots, the hydrogel was fully thermo-reversible and its gel-sol transition was achieved after the addition of either an oxidizing agent or a competitive guest to Fc.

  5. Evaluation of a polyacrylamide hydrogel in the treatment of induced osteoarthritis in a goat model

    DEFF Research Database (Denmark)

    Tnibar, Aziz; Persson, Ann; Jensen, Henrik Elvang

    2014-01-01

    Polyacrylamide hydrogel (PAAG) is an inert, non-degradable, non-immunogenic polymer gel with high viscoelasticity consisting of 97.5% sterile water and 2.5% cross-linked polyacrylamide. Its biocompatibility in soft tissues has been demonstrated. PAAG has recently been tested for the treatment of ...... of osteoarthritis (OA) in horses with highly encouraging results; however no standardized experimental studies have been done to explore its efficacy. The purpose of this study was to evaluate PAAG in the treatment of induced OA in a goat model...

  6. Bioprinting three-dimensional cell-laden tissue constructs with controllable degradation.

    Science.gov (United States)

    Wu, Zhengjie; Su, Xin; Xu, Yuanyuan; Kong, Bin; Sun, Wei; Mi, Shengli

    2016-04-19

    Alginate hydrogel is a popular biologically inert material that is widely used in 3D bioprinting, especially in extrusion-based printing. However, the printed cells in this hydrogel could not degrade the surrounding alginate gel matrix, causing them to remain in a poorly proliferating and non-differentiating state. Here, we report a novel study of the 3D printing of human corneal epithelial cells (HCECs)/collagen/gelatin/alginate hydrogel incubated with a medium containing sodium citrate to obtain degradation-controllable cell-laden tissue constructs. The 3D-printed hydrogel network with interconnected channels and a macroporous structure was stable and achieved high cell viability (over 90%). By altering the mole ratio of sodium citrate/sodium alginate, the degradation time of the bioprinting constructs can be controlled. Cell proliferation and specific marker protein expression results also revealed that with the help of sodium citrate degradation, the printed HCECs showed a higher proliferation rate and greater cytokeratin 3(CK3) expression, indicating that this newly developed method may help to improve the alginate bioink system for the application of 3D bioprinting in tissue engineering.

  7. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    OpenAIRE

    Bai, Yuanyuan; Chen, Baohong; Xiang, Feng; Zhou, Jinxiong; Wang, Hong; Suo, Zhigang

    2014-01-01

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chlorid...

  8. Alkylation of human hair keratin for tunable hydrogel erosion and drug delivery in tissue engineering applications.

    Science.gov (United States)

    Han, Sangheon; Ham, Trevor R; Haque, Salma; Sparks, Jessica L; Saul, Justin M

    2015-09-01

    Polymeric biomaterials that provide a matrix for cell attachment and proliferation while achieving delivery of therapeutic agents are an important component of tissue engineering and regenerative medicine strategies. Keratins are a class of proteins that have received attention for numerous tissue engineering applications because, like other natural polymers, they promote favorable cell interactions and have non-toxic degradation products. Keratins can be extracted from various sources including human hair, and they are characterized by a high percentage of cysteine residues. Thiol groups on reductively extracted keratin (kerateine) form disulfide bonds, providing a more stable cross-linked hydrogel network than oxidatively extracted keratin (keratose) that cannot form disulfide crosslinks. We hypothesized that an iodoacetamide alkylation (or "capping") of cysteine thiol groups on the kerateine form of keratin could be used as a simple method to modulate the levels of disulfide crosslinking in keratin hydrogels, providing tunable rates of gel erosion and therapeutic agent release. After alkylation, the alkylated kerateines still formed hydrogels and the alkylation led to changes in the mechanical and visco-elastic properties of the materials consistent with loss of disulfide crosslinking. The alkylated kerateines did not lead to toxicity in MC3T3-E1 pre-osteoblasts. These cells adhered to keratin at levels comparable to fibronectin and greater than collagen. Alkylated kerateine gels eroded more rapidly than non-alkylated kerateine and this control over erosion led to tunable rates of delivery of rhBMP-2, rhIGF-1, and ciprofloxacin. These results demonstrate that alkylation of kerateine cysteine residues provides a cell-compatible approach to tune rates of hydrogel erosion and therapeutic agent release within the context of a naturally-derived polymeric system. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yuanyuan; Xiang, Feng; Wang, Hong, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [Electronic Materials Research Laboratory, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Baohong; Zhou, Jinxiong [State Key Laboratory for Strength and Vibration of Mechanical Structures, International Center for Applied Mechanics and School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China); Suo, Zhigang, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [School of Engineering and Applied Sciences, Kavli Institute of Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2014-10-13

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

  10. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    International Nuclear Information System (INIS)

    Bai, Yuanyuan; Xiang, Feng; Wang, Hong; Chen, Baohong; Zhou, Jinxiong; Suo, Zhigang

    2014-01-01

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

  11. Gelatin- and starch-based hydrogels. Part A: Hydrogel development, characterization and coating.

    Science.gov (United States)

    Van Nieuwenhove, Ine; Salamon, Achim; Peters, Kirsten; Graulus, Geert-Jan; Martins, José C; Frankel, Daniel; Kersemans, Ken; De Vos, Filip; Van Vlierberghe, Sandra; Dubruel, Peter

    2016-11-05

    The present work aims at constructing the ideal scaffold matrix of which the physico-chemical properties can be altered according to the targeted tissue regeneration application. Ideally, this scaffold should resemble the natural extracellular matrix (ECM) as close as possible both in terms of chemical composition and mechanical properties. Therefore, hydrogel films were developed consisting of methacrylamide-modified gelatin and starch-pentenoate building blocks because the ECM can be considered as a crosslinked hydrogel network consisting of both polysaccharides and structural, signaling and cell-adhesive proteins. For the gelatin hydrogels, three different substitution degrees were evaluated including 31%, 72% and 95%. A substitution degree of 32% was applied for the starch-pentenoate building block. Pure gelatin hydrogels films as well as interpenetrating networks with gelatin and starch were developed. Subsequently, these films were characterized using gel fraction and swelling experiments, high resolution-magic angle spinning (1)H NMR spectroscopy, rheology, infrared mapping and atomic force microscopy. The results indicate that both the mechanical properties and the swelling extent of the developed hydrogel films can be controlled by varying the chemical composition and the degree of substitution of the methacrylamide-modified gelatin applied. The storage moduli of the developed materials ranged between 14 and 63kPa. Phase separation was observed for the IPNs for which separated starch domains could be distinguished located in the surrounding gelatin matrix. Furthermore, we evaluated the affinity of aggrecan for gelatin by atomic force microscopy and radiolabeling experiments. We found that aggrecan can be applied as a bioactive coating for gelatin hydrogels by a straightforward physisorption procedure. Thus, we achieved distinct fine-tuning of the physico-chemical properties of these hydrogels which render them promising candidates for tissue engineering

  12. Hydrogel Walkers with Electro-Driven Motility for Cargo Transport.

    Science.gov (United States)

    Yang, Chao; Wang, Wei; Yao, Chen; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

    2015-08-28

    In this study, soft hydrogel walkers with electro-driven motility for cargo transport have been developed via a facile mould-assisted strategy. The hydrogel walkers consisting of polyanionic poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylamide) exhibit an arc looper-like shape with two "legs" for walking. The hydrogel walkers can reversibly bend and stretch via repeated "on/off" electro-triggers in electrolyte solution. Based on such bending/stretching behaviors, the hydrogel walkers can move their two "legs" to achieve one-directional walking motion on a rough surface via repeated "on/off" electro-triggering cycles. Moreover, the hydrogel walkers loaded with very heavy cargo also exhibit excellent walking motion for cargo transport. Such hydrogel systems create new opportunities for developing electro-controlled soft systems with simple design/fabrication strategies in the soft robotic field for remote manipulation and transportation.

  13. Comparison of Pectin Hydrogel Collection Methods in Microfluidic Device

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chaeyeon; Park, Ki-Su; Kang, Sung-Min; Kim, Jongmin; Song, YoungShin; Lee, Chang-Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2015-12-15

    This study investigated the effect of different collection methods on physical properties of pectin hydrogels in microfluidic synthetic approach. The pectin hydrogels were simply produced by the incorporation of calcium ions dissolved in continuous mineral oil. Then, different collection methods, pipetting, tubing, and settling, for harvesting pectin hydrogels were applied. The settling method showed most uniform and monodispersed hydrogels. In the case of settling, a coefficient of variation was 3.46 which was lower than pipetting method (18.60) and tubing method (14.76). Under the settling method, we could control the size of hydrogels, ranging from 30 μm to 180 μm, by simple manipulation of the viscosity of pectin and volumetric flow rate of dispersed and continuous phase. Finally, according to the characteristics of simple encapsulation of biological materials, we envision that the pectin hydrogels can be applied to drug delivery, food, and biocompatible materials.

  14. Optimizing Double-Network Hydrogel for Biomedical Soft Robots.

    Science.gov (United States)

    Banerjee, Hritwick; Ren, Hongliang

    2017-09-01

    Double-network hydrogel with standardized chemical parameters demonstrates a reasonable and viable alternative to silicone in soft robotic fabrication due to its biocompatibility, comparable mechanical properties, and customizability through the alterations of key variables. The most viable hydrogel sample in our article shows tensile strain of 851% and maximum tensile strength of 0.273 MPa. The elasticity and strength range of this hydrogel can be customized according to application requirements by simple alterations in the recipe. Furthermore, we incorporated Agar/PAM hydrogel into our highly constrained soft pneumatic actuator (SPA) design and eventually produced SPAs with escalated capabilities, such as larger range of motion, higher force output, and power efficiency. Incorporating SPAs made of Agar/PAM hydrogel resulted in low viscosity, thermos-reversibility, and ultralow elasticity, which we believe can help to combine with the other functions of hydrogel, tailoring a better solution for fabricating biocompatible soft robots.

  15. Hydrogel-based piezoresistive sensor for the detection of ethanol

    Directory of Open Access Journals (Sweden)

    J. Erfkamp

    2018-04-01

    Full Text Available This article describes a low-cost sensor for the detection of ethanol in alcoholic beverages, which combines alcohol-sensitive hydrogels based on acrylamide and bisacrylamide and piezoresistive sensors. For reproducible measurements, the reversible swelling and deswelling of the hydrogel were shown via microscopy. The response time of the sensor depends on the swelling kinetics of the hydrogel. The selectivity of the hydrogel was tested in different alcohols. In order to understand the influence of monomer and crosslinker content on the swelling degree and on the sensitivity of the hydrogels, gels with variable concentrations of acrylamide and bisacrylamide were synthesized and characterized in different aqueous solutions with alcohol contents. The first measurements of such hydrogel-based piezoresistive ethanol sensors demonstrated a high sensitivity and a short response time over several measuring cycles.

  16. Stimuli-responsive hydrogels in drug delivery and tissue engineering.

    Science.gov (United States)

    Sood, Nikhil; Bhardwaj, Ankur; Mehta, Shuchi; Mehta, Abhinav

    2016-01-01

    Hydrogels are the three-dimensional network structures obtained from a class of synthetic or natural polymers which can absorb and retain a significant amount of water. Hydrogels are one of the most studied classes of polymer-based controlled drug release. These have attracted considerable attention in biochemical and biomedical fields because of their characteristics, such as swelling in aqueous medium, biocompatibility, pH and temperature sensitivity or sensitivity towards other stimuli, which can be utilized for their controlled zero-order release. The hydrogels are expected to explore new generation of self-regulated delivery system having a wide array of desirable properties. This review highlights the exciting opportunities and challenges in the area of hydrogels. Here, we review different literatures on stimuli-sensitive hydrogels, such as role of temperature, electric potential, pH and ionic strength to control the release of drug from hydrogels.

  17. Rationally designed synthetic protein hydrogels with predictable mechanical properties.

    Science.gov (United States)

    Wu, Junhua; Li, Pengfei; Dong, Chenling; Jiang, Heting; Bin Xue; Gao, Xiang; Qin, Meng; Wang, Wei; Bin Chen; Cao, Yi

    2018-02-12

    Designing synthetic protein hydrogels with tailored mechanical properties similar to naturally occurring tissues is an eternal pursuit in tissue engineering and stem cell and cancer research. However, it remains challenging to correlate the mechanical properties of protein hydrogels with the nanomechanics of individual building blocks. Here we use single-molecule force spectroscopy, protein engineering and theoretical modeling to prove that the mechanical properties of protein hydrogels are predictable based on the mechanical hierarchy of the cross-linkers and the load-bearing modules at the molecular level. These findings provide a framework for rationally designing protein hydrogels with independently tunable elasticity, extensibility, toughness and self-healing. Using this principle, we demonstrate the engineering of self-healable muscle-mimicking hydrogels that can significantly dissipate energy through protein unfolding. We expect that this principle can be generalized for the construction of protein hydrogels with customized mechanical properties for biomedical applications.

  18. Design and characterization of tunable hydrogels to examine microenvironmental regulation of breast cancer recurrence

    Science.gov (United States)

    Sawicki, Lisa A.

    Late recurrence of breast cancer within distant metastatic tissue sites is often difficult to diagnose and treat, resulting in poor prognosis for patients. It is hypothesized that cells may go dormant by interactions with or lack of adhesion to the extracellular matrix (ECM) within these tissues, which differs from native breast tissue. The metastatic ECM is a complex microenvironment, containing a mixture of mechanical and chemical cues to which cells respond. To investigate how the ECM regulates cancer recurrence, two-dimensional (2D, plates) and three-dimensional (3D, naturally-derived scaffolds) in vitro culture models have been used. However, lack of complexity (2D), mechanical property control (2D, 3D), and chemical property control (3D) makes it challenging to identify key factors involved in regulating dormancy or activation in these systems. The development of synthetic polymer-based scaffolds in recent years provides an alternate route to investigating cellular response to the presentation of microenvironmental cues in 3D. Initially bioinert, these scaffolds may be modified with chemical ligands to permit cell-matrix interactions and their mechanical properties may be precisely tuned to mimic different tissue sites. The goal of this dissertation is to develop and characterize a novel synthetic material for cell culture applications and to examine how physical and chemical factors in this microenvironment regulate breast cancer activation. Specifically, we have developed a novel poly(ethylene glycol) (PEG)-based hydrogel scaffold for in vitro cell culture. PEG modified with thiols and peptides containing alloxycarbonyl-protected lysines (containing a reactive vinyl) react rapidly upon the application of light in the presence of a photoinitiator, lithium acylphosphinate ( minutes). Scaffold mechanical properties are tuned by varying macromer concentration to mimic soft metastatic site tissue ECMs (Young's modulus 600 - 6000 Pa). These properties remain

  19. Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady [Atomic Energy Authority, Nasr City (Egypt). National Center for Radiation Research and Technology (NCRTT)

    2017-07-01

    Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

  20. HYDROXYETHYL METHACRYLATE BASED NANOCOMPOSITE HYDROGELS WITH TUNABLE PORE ARCHITECTURE

    Directory of Open Access Journals (Sweden)

    Erhan Bat

    2016-10-01

    Full Text Available Hydroxyethyl methacrylate (HEMA based hydrogels have found increasing number of applications in areas such as chromatographic separations, controlled drug release, biosensing, and membrane separations. In all these applications, the pore size and pore interconnectivity are crucial for successful application of these materials as they determine the rate of diffusion through the matrix. 2-Hydroxyethyl methacrylate is a water soluble monomer but its polymer, polyHEMA, is not soluble in water. Therefore, during polymerization of HEMA in aqueous media, a porous structure is obtained as a result of phase separation. Pore size and interconnectivity in these hydrogels is a function of several variables such as monomer concentration, cross-linker concentration, temperature etc. In this study, we investigated the effect of monomer concentration, graphene oxide addition or clay addition on hydrogel pore size, pore interconnectivity, water uptake, and thermal properties. PolyHEMA hydrogels have been prepared by redox initiated free radical polymerization of the monomer using ethylene glycol dimethacrylate as a cross-linker. As a nanofiller, a synthetic hectorite Laponite® XLG and graphene oxide were used. Graphene oxide was prepared by the Tour Method. Pore morphology of the pristine HEMA based hydrogels and nanocomposite hydrogels were studied by scanning electron microscopy. The formed hydrogels were found to be highly elastic and flexible. A dramatic change in the pore structure and size was observed in the range between 22 to 24 wt/vol monomer at 0.5 % of cross-linker. In this range, the hydrogel morphology changes from typical cauliflower architecture to continuous hydrogel with dispersed water droplets forming the pores where the pores are submicron in size and show an interconnected structure. Such controlled pore structure is highly important when these hydrogels are used for solute diffusion or when there’s flow through monolithic hydrogels

  1. Supramolecular polyaniline hydrogel as a support for urease

    International Nuclear Information System (INIS)

    Słoniewska, Anna; Pałys, Barbara

    2014-01-01

    Supramolecular hydrogels of conducting polymers are successfully used in bioelectrochemistry because of their mechanical and swelling properties of gels added to the specific electron transport properties of conducting polymers. We have studied polyaniline-poly(styrene sulfonate) (PANI–PSS) hydrogel as a substrate for the urease. The hydrogels were synthesized at pH = 0 and pH = 5. PANI–PSS hydrogel is a supramolecular self-assembly material consisting of positively-charged PANI chains and negatively-charged PSS chains. The hydrogel was studied by cyclic voltammetry, infrared and Raman spectroscopy and Scanning Electron Microscopy (SEM). Raman spectra revealed presence of phenazine rings in the hydrogel structure. Phenazine rings form covalent cross-linkers contributing to the hydrogel mechanical stability. The covalent cross-linkers influence the cyclic voltammetry responses of the hydrogel in acidic media. We tested the activity of urease immobilized in the PANI–PSS hydrogel by the physical adsorption or by the covalent bonding with the carbodiimide reaction. The enzyme immobilized in hydrogels prepared at higher pH value reveals significantly higher sensitivity. The method of the enzyme immobilization has smaller impact on the sensitivity. All hydrogel sensors reveal largely higher sensitivity to urea comparing to urease immobilized in the typical electrochemically deposited PANI films. The sensitivity of urease covalently bond to the hydrogel obtained at pH = 5 was as high as 1693 μA/(mol dm 3 ). The sensor response was linear in the urea concentration range from 10 −4 to 7 × 10 −2 mol/dm 3

  2. Controlled release fertilizers using superabsorbent hydrogel prepared by gamma radiation

    International Nuclear Information System (INIS)

    Elbarbary, Ahmed M.; Ghobashy, Mohamed Mohamady

    2017-01-01

    Superabsorbent hydrogels (PVP/CMC) based on polyvinylpyrrolidone (PVP)/carboxylmethyl cellulose (CMC) of different copolymer compositions were prepared by gamma radiation. Factors affecting the gel content (%) and the swelling ratio (g/g) of hydrogel such as irradiation dose as well as copolymer composition were investigated. With increasing the CMC content in PVP/CMC hydrogels, increases the swelling and improves the water retention capability. The high swelling ratio was observed at copolymer composition of PVP/CMC (60/40). Fast swelling of the hydrogels was obtained after 20 min. The effect of different fertilizers and buffers of different pH's on equilibrium swelling of hydrogels was investigated. Fertilizers such as urea, monopotassium-phosphate (MPK), and nitrogen-phosphate-potassium (NPK) were loaded onto the hydrogel to supply nitrogen, potassium and phosphorous nutrients. PVP/CMC hydrogels retained 28-36% after 72 h and slow retention was noticed up to 9 days. The swelling of hydrogel in fertilizer solutions is lower than that in water. The hydrogels showed adsorption desorption of fertilizers which governs by slow release property. The release rate of urea is much higher 10 times than that of phosphate. After 3 days, urea released 60%, while phosphate released 10-12%. The applicability of PVP/CMC hydrogels in the agricultural fields shows greater growth effect on zea maize plants. The growth of zea maize plant in soil mixed with PVP/CMC hydrogels loaded fertilizers is greater than untreated soil. The slow release fertilize, the high swelling and the slow water retention behaviors of PVP/CMC hydrogels encourage their use as safer release systems for fertilizers and as soil conditioner in agricultural applications.

  3. Viscoelastic response of hydrogel materials at finite strains

    OpenAIRE

    Skovly, Martin Johannessen

    2015-01-01

    Hydrogel materials are very soft materials consisting of polymer networks and solvent molecules. The materials may exhibit large volume changes depending on its external chemical and mechanical environment and have viscoelastic properties which is common for many polymeric materials. In order to model the material response with the finite element method, a hydrogel constitutive model have been combined with finite viscoelastic theory and the resulting viscoelastic hydrogel constitutive model ...

  4. Production of bioinspired and rationally designed polymer hydrogels for controlled delivery of therapeutic proteins

    Science.gov (United States)

    Kim, Sung Hye

    Hydrogel systems for controlled delivery therapeutic growth factors have been developed in a wide spectrum of strategies: these systems aim for the release of growth factors via a passive diffusion, electrostatic interaction, degradation of hydrogels, and responsiveness to external stimuli. Heparin, a highly sulfated glycosaminoglycan (GAG), was employed for a targeted delivery system of vascular endothelial growth factor (VEGF) to endothelial cells overexpressing a relevant receptor VEGFR-2. Addition of dimeric VEGF to 4-arm star-shaped poly(ethylene glycol) (PEG) immobilized with low-molecular weight heparin (LMWH) afforded a non-covalently assembled hydrogel via interaction between heparin and VEGF, with storage modulus 10 Pa. The release of VEGF and hydrogel erosion reached maximum 100 % at day 4 in the presence of VEGFR-2 overexpressing pocine aortic endothelial cell (PAE/KDR), while those of 80% were achieved via passive release at day 5 in the presence of PAE cell lacking VEGFR-2 or in the absence of cell, indicating that the release of VEGF was in targeted manner toward cell receptor. The proliferation of PAE/KDR in the presence of [PEG-LMWH/VEGF] hydrogel was greater by ca. 30% at day 4 compared to that of PAE, confirming that the release of VEGF was in response to the cellular demand. The phosphorylation fraction of VEGFR-2 on PAE/KDR was greater in the presence of [PEG-LMWH/VEGF] hydrogel, increasing from 0.568 at day 1 to 0.790 at day 4, whereas it was maintained at 0.230 at day 4 in the presence of [PEG-LMWH] hydrogel. This study has proven that this hydrogel, assembled via bio-inspired non-covalent interaction, liberating VEGFon celluar demand to target cell, eroding upon VEGF release, and triggering endothelial cell proliferation, could be used in multiple applications including targeted delivery and angiogenesis. Heparin has been widely exploited in growth factor delivery systems owing to its ability to bind many growth factors through the flexible

  5. Development of injectable hydrogels for nucleus pulposus replacement

    Science.gov (United States)

    Thomas, Jonathan D.

    Intervertebral disc degeneration has been reported as the underlying cause for 75% of cases of lower back pain and is marked by dehydration of the nucleus pulposus within the intervertebral disc. There have been many implant designs to replace the nucleus pulposus. Some researchers have proposed the replacement of the nucleus pulposus with hydrogel materials. The insertion of devices made from these materials further compromises the annulus of the disc. An ideal nucleus replacement could be injected into the disc space and form a solid in vivo. However, injectable replacements using curing elastomers and thermoplastic materials are not ideal because of the potentially harmful exothermic heat evolved from their reactions and the toxicity of the reactants used. We propose a hydrogel system that can be injected as a liquid at 25°C and solidified to yield a hydrogel within the intervertebral disc at 37°C. In aqueous solutions, these polymers have Lower Critical Solution Temperatures (LCST) between 25-37°C, making them unique candidate materials for this application. Poly(N-isopropylacrylamide) (PNIPAAm) is the most widely studied LCST polymer due to its drastic transition near body temperature. However, by itself, pure PNIPAAm forms a hydrogel that has low water content and can readily undergo plastic deformation. To increase the water content and impart elasticity to PNIPAAm hydrogels, grafted and branched hydrogel systems were created that incorporated the thermogelling PNIPAAm and hydrophilic poly(ethylene glycol) (PEG). In this research, the effects of polymer composition and monomer to initiator ratio, which controls polymer MW, on the in vitro swelling properties (mass, chemical, and compressive mechanical stability) of hydrogels formed from aqueous solutions of these polymers were evaluated. Immersion studies were also conducted in solutions to simulate the osmotic environment of the nucleus pulposus. The effects of repeated compression and unloading cycles

  6. PVA/atapulgite hydrogels; Hidrogeis de PVA/atapulgita

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, R.N.; Soares, G.A., E-mail: nunes@metalmat.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Paranhos, C.M. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil); Barreto, L.S. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil)

    2010-07-01

    PVA hydrogels can be used as wound-healing as a consequence of their biocompatibility, flexibility, etc. In order to improve mechanical resistance of wound-healing, polymeric hydrogels reinforced with clay have been studied. Among national clays, attapulgite stands out. Once it is a natural material, acid treatment can be required in order to remove impurities. In the present work, PVA hydrogels reinforced with attapulgite were produced and they were characterized by swelling behavior, XRD, DSC and traction test. Among all properties studied, hydrogels reinforced with activated attapulgite showed better mechanical resistance and Young module than the other samples. (author)

  7. Responsive Hydrogels for Label-Free Signal Transduction within Biosensors

    Directory of Open Access Journals (Sweden)

    Kamila Gawel

    2010-04-01

    Full Text Available Hydrogels have found wide application in biosensors due to their versatile nature. This family of materials is applied in biosensing either to increase the loading capacity compared to two-dimensional surfaces, or to support biospecific hydrogel swelling occurring subsequent to specific recognition of an analyte. This review focuses on various principles underpinning the design of biospecific hydrogels acting through various molecular mechanisms in transducing the recognition event of label-free analytes. Towards this end, we describe several promising hydrogel systems that when combined with the appropriate readout platform and quantitative approach could lead to future real-life applications.

  8. Progress in lignin hydrogels and nanocomposites for water purification

    DEFF Research Database (Denmark)

    Tamulevicius, Sigitas; Thakur, Sourbh; Govender, Penny P.

    2017-01-01

    -based hydrogels have shown excellent performance for removal of various pollutants from water. The adsorption properties of lignin based hydrogels can further be improved by using a combination of nanomaterials and lignin that results in promising hydrogel nanocomposites. In nature, the most abundant structures...... are formed by the combination of lignin, cellulose and hemicelluloses. In this article, we have attempted to comprehensively review the research work carried out in the direction of usage of lignin-based hydrogel for removal of toxic pollutants including metal ions and dyes....

  9. Bioengineering vascularized tissue constructs using an injectable cell-laden enzymatically crosslinked collagen hydrogel derived from dermal extracellular matrix.

    Science.gov (United States)

    Kuo, Kuan-Chih; Lin, Ruei-Zeng; Tien, Han-Wen; Wu, Pei-Yun; Li, Yen-Cheng; Melero-Martin, Juan M; Chen, Ying-Chieh

    2015-11-01

    Tissue engineering promises to restore or replace diseased or damaged tissue by creating functional and transplantable artificial tissues. The development of artificial tissues with large dimensions that exceed the diffusion limitation will require nutrients and oxygen to be delivered via perfusion instead of diffusion alone over a short time period. One approach to perfusion is to vascularize engineered tissues, creating a de novo three-dimensional (3D) microvascular network within the tissue construct. This significantly shortens the time of in vivo anastomosis, perfusion and graft integration with the host. In this study, we aimed to develop injectable allogeneic collagen-phenolic hydroxyl (collagen-Ph) hydrogels that are capable of controlling a wide range of physicochemical properties, including stiffness, water absorption and degradability. We tested whether collagen-Ph hydrogels could support the formation of vascularized engineered tissue graft by human blood-derived endothelial colony-forming cells (ECFCs) and bone marrow-derived mesenchymal stem cells (MSC) in vivo. First, we studied the growth of adherent ECFCs and MSCs on or in the hydrogels. To examine the potential formation of functional vascular networks in vivo, a liquid pre-polymer solution of collagen-Ph containing human ECFCs and MSCs, horseradish peroxidase and hydrogen peroxide was injected into the subcutaneous space or abdominal muscle defect of an immunodeficient mouse before gelation, to form a 3D cell-laden polymerized construct. These results showed that extensive human ECFC-lined vascular networks can be generated within 7 days, the engineered vascular density inside collagen-Ph hydrogel constructs can be manipulated through refinable mechanical properties and proteolytic degradability, and these networks can form functional anastomoses with the existing vasculature to further support the survival of host muscle tissues. Finally, optimized conditions of the cell-laden collagen

  10. Hydrogels for central nervous system therapeutic strategies.

    Science.gov (United States)

    Russo, Teresa; Tunesi, Marta; Giordano, Carmen; Gloria, Antonio; Ambrosio, Luigi

    2015-12-01

    The central nervous system shows a limited regenerative capacity, and injuries or diseases, such as those in the spinal, brain and retina, are a great problem since current therapies seem to be unable to achieve good results in terms of significant functional recovery. Different promising therapies have been suggested, the aim being to restore at least some of the lost functions. The current review deals with the use of hydrogels in developing advanced devices for central nervous system therapeutic strategies. Several approaches, involving cell-based therapy, delivery of bioactive molecules and nanoparticle-based drug delivery, will be first reviewed. Finally, some examples of injectable hydrogels for the delivery of bioactive molecules in central nervous system will be reported, and the key features as well as the basic principles in designing multifunctional devices will be described. © IMechE 2015.

  11. Bioinspired Hydrogels to Engineer Cancer Microenvironments.

    Science.gov (United States)

    Park, Kyung Min; Lewis, Daniel; Gerecht, Sharon

    2017-06-21

    Recent research has demonstrated that tumor microenvironments play pivotal roles in tumor development and metastasis through various physical, chemical, and biological factors, including extracellular matrix (ECM) composition, matrix remodeling, oxygen tension, pH, cytokines, and matrix stiffness. An emerging trend in cancer research involves the creation of engineered three-dimensional tumor models using bioinspired hydrogels that accurately recapitulate the native tumor microenvironment. With recent advances in materials engineering, many researchers are developing engineered tumor models, which are promising platforms for the study of cancer biology and for screening of therapeutic agents for better clinical outcomes. In this review, we discuss the development and use of polymeric hydrogel materials to engineer native tumor ECMs for cancer research, focusing on emerging technologies in cancer engineering that aim to accelerate clinical outcomes.

  12. Controlled Delivery of Vancomycin via Charged Hydrogels.

    Directory of Open Access Journals (Sweden)

    Carl T Gustafson

    Full Text Available Surgical site infection (SSI remains a significant risk for any clean orthopedic surgical procedure. Complications resulting from an SSI often require a second surgery and lengthen patient recovery time. The efficacy of antimicrobial agents delivered to combat SSI is diminished by systemic toxicity, bacterial resistance, and patient compliance to dosing schedules. We submit that development of localized, controlled release formulations for antimicrobial compounds would improve the effectiveness of prophylactic surgical wound antibiotic treatment while decreasing systemic side effects. Our research group developed and characterized oligo(poly(ethylene glycolfumarate/sodium methacrylate (OPF/SMA charged copolymers as biocompatible hydrogel matrices. Here, we report the engineering of this copolymer for use as an antibiotic delivery vehicle in surgical applications. We demonstrate that these hydrogels can be efficiently loaded with vancomycin (over 500 μg drug per mg hydrogel and this loading mechanism is both time- and charge-dependent. Vancomycin release kinetics are shown to be dependent on copolymer negative charge. In the first 6 hours, we achieved as low as 33.7% release. In the first 24 hours, under 80% of total loaded drug was released. Further, vancomycin release from this system can be extended past four days. Finally, we show that the antimicrobial activity of released vancomycin is equivalent to stock vancomycin in inhibiting the growth of colonies of a clinically derived strain of methicillin-resistant Staphylococcus aureus. In summary, our work demonstrates that OPF/SMA hydrogels are appropriate candidates to deliver local antibiotic therapy for prophylaxis of surgical site infection.

  13. Biocompatible hydrogels in spinal cord injury repair

    Czech Academy of Sciences Publication Activity Database

    Hejčl, Aleš; Lesný, Petr; Přádný, Martin; Michálek, Jiří; Jendelová, Pavla; Štulík, J.; Syková, Eva

    2008-01-01

    Roč. 57, Suppl.3 (2008), S121-S132 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LC554; GA ČR GA309/06/1246 Grant - others:GA ČR(CZ) 1A8697 Institutional research plan: CEZ:AV0Z50390703; CEZ:AV0Z40500505 Keywords : Spinal cord injury * Hydrogel * Tissue engineering Subject RIV: FH - Neurology Impact factor: 1.653, year: 2008

  14. Chitosan composite hydrogels reinforced with natural clay nanotubes.

    Science.gov (United States)

    Huang, Biao; Liu, Mingxian; Zhou, Changren

    2017-11-01

    Here, chitosan composites hydrogels were prepared by addition of halloysite nanotubes (HNTs) in the chitosan KOH/LiOH/urea solution. The raw chitosan and chitosan/HNTs composite hydrogels were obtained by heat treatment at 60°C for 8h and then regeneration in ethanol solution. The viscosity of the composite solution is increased with HNTs content. The Fourier transform infrared spectroscopy (FT-IR) shows that the hydrogen bonds interactions exist between the HNTs and the chitosan. X-ray diffraction (XRD) results show that the crystal structure of HNT is not changed in the composite hydrogels. The compressive property test and storage modulus determination show that the mechanical properties and anti-deformation ability of the composite hydrogel significantly increase owing to the reinforcing effect of HNTs. The composites hydrogel with 66.7% HNTs can undergo 7 times compression cycles without breaking with compressive strength of 0.71MPa at 70% deformation, while pure chitosan hydrogel is broken after bearing 5 compression cycles with compressive strength of 0.14MPa and a maximum deformation of 59%. A porous structure with pore size of 100-500μm is found in the composite hydrogels by scanning electron microscopy (SEM), and the pore size and the swelling ratio in NaCl solution decrease by the addition of HNTs and the immersing of ethanol. Chitosan/HNTs composite hydrogels show low cytotoxicity towards MC3T3-E1 cells. Also, the composite hydrogels show a maximum drug entrapment efficiency of 45.7% for doxorubicin (DOX) which is much higher than that of pure chitosan hydrogel (27.5%). All the results illustrate that the chitosan/HNTs composite hydrogels show promising applications as biomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Fibre-reinforced hydrogels for tissue engineering

    Science.gov (United States)

    Waters, Sarah; Byrne, Helen; Chen, Mike; Dias Castilho, Miguel; Kimpton, Laura; Please, Colin; Whiteley, Jonathan

    2017-11-01

    Tissue engineers aim to grow replacement tissues in vitro to replace those in the body that have been damaged through age, trauma or disease. One approach is to seed cells within a scaffold consisting of an interconnected 3D-printed lattice of polymer fibres, cast in a hydrogel, and subject the construct (cell-seeded scaffold) to an applied load in a bioreactor. A key question is to understand how this applied load is distributed throughout the construct to the mechanosensitive cells. To address this, we exploit the disparate length scales (small inter-fibre spacing compared with construct dimensions). The fibres are treated as a linear elastic material and the hydrogel as a poroelastic material. We employ homogenisation theory to derive equations governing the material properties of a periodic, elastic-poroelastic composite. To validate the mobel, model solutions are compared to experimental data describing the unconfined compression of the fibre-reinforced hydrogels. The model is used to derive the bulk mechanical properties of a cylindrical construct of the composite material for a range of fibre spacings, and the local mechanical environment experienced by cells embedded within the construct is determined. Funded by the European Union Seventh Framework Programme (FP7/2007-2013).

  16. Water diffusion in phosphate-containing hydrogels

    International Nuclear Information System (INIS)

    George, K.A.; Wentrup-Byrne, E.; Hill, D.J.T.; Whittaker, A.K.

    2003-01-01

    An understanding of the kinetics and diffusion of liquids through polymeric hydrogels is critical for the successful design and application of these materials in biomedical field, particularly as controlled drug delivery systems. In this study, the mechanisms of water transport and parameters that describe the diffusion process in crosslinked poly(2-hydroxyethylmethacrylate-co-methyloxyethylene phosphate), poly(HEMA-co-MOEP) polymers were investigated. The copolymerisation of HEMA with MOEP was initiated by γ radiolysis with full conversion of monomer to polymer. The sorption of water into the polymers with 0 - 30 mol% MOEP was monitored gravimetrically over a period of 2 - 3 weeks. This study provided an insight into the diffusion mechanism and showed that the PHEMA hydrogel displayed concentration-independent Fickian diffusion. As the concentration of MOEP in the network increased, the diffusion rate and the rigidity of the network also increased in a linear fashion. NMR imaging was used in conjunction with the gravimetric study to elucidate the transport mechanisms, diffusion coefficients and proportionality constants governing the water diffusion in the phosphate-containing polymers. The hydrogels with 3 - 20 mol% MOEP exhibited exponential concentration-dependent Fickian diffusion and the transport mechanism in the system with 30 mol% MOEP was shown to be anomalous. The systems with greater concentrations of MOEP displayed a high degree of fracturing during water sorption and resulted in the ultimate destruction of the cylindrical geometry

  17. Connections matter: channeled hydrogels to improve vascularization

    Directory of Open Access Journals (Sweden)

    Severin eMuehleder

    2014-11-01

    Full Text Available The use of cell-laden hydrogels to engineer soft tissue has been emerging within the past years. Despite several newly developed and sophisticated techniques to encapsulate different cell types the importance of vascularization of the engineered constructs is often underestimated. As a result, cell death within a construct leads to impaired function and inclusion of the implant. Here, we discuss the fabrication of hollow channels within hydrogels as a promising strategy to facilitate vascularization. Furthermore, we present an overview on the feasible use of removable spacers, 3D laser- and planar processing strategies to create channels within hydrogels. The implementation of these structures promotes control over cell distribution and increases oxygen transport and nutrient supply in vitro. However, many studies lack the use of endothelial cells in their approaches leaving out an important factor to enhance vessel ingrowth and anastomosis formation upon implantation. In addition, the adequate endothelial cell type needs to be considered to make these approaches bridge the gap to in vivo applications.

  18. Connections matter: channeled hydrogels to improve vascularization.

    Science.gov (United States)

    Muehleder, Severin; Ovsianikov, Aleksandr; Zipperle, Johannes; Redl, Heinz; Holnthoner, Wolfgang

    2014-01-01

    The use of cell-laden hydrogels to engineer soft tissue has been emerging within the past years. Despite, several newly developed and sophisticated techniques to encapsulate different cell types the importance of vascularization of the engineered constructs is often underestimated. As a result, cell death within a construct leads to impaired function and inclusion of the implant. Here, we discuss the fabrication of hollow channels within hydrogels as a promising strategy to facilitate vascularization. Furthermore, we present an overview on the feasible use of removable spacers, 3D laser-, and planar processing strategies to create channels within hydrogels. The implementation of these structures promotes control over cell distribution and increases oxygen transport and nutrient supply in vitro. However, many studies lack the use of endothelial cells in their approaches leaving out an important factor to enhance vessel ingrowth and anastomosis formation upon implantation. In addition, the adequate endothelial cell type needs to be considered to make these approaches bridge the gap to in vivo applications.

  19. Synthesis and application of intelligent hydrogels

    International Nuclear Information System (INIS)

    Kaetsu, I.; Uchida, K.; Sutani, K.; Nakayama, H.; Tamori, A.

    2000-01-01

    The authors have studied synthesis and application of stimule-sensitive and responsive hydrogels. In this report, two kinds of investigations were carried out on the intelligent hydrogels and the applications with radiation techniques. 1. Synthesis of temperature responsive sol-gel transition polymer and the application to drug delivery systems. Polysopropyl acrylamide is a typical temperature responsive polymers and the copolymers show broad variation of LCST (sol-gel transition temperature). The various copolymers of isopropyl acrylamide were synthesized by UV or radiation. 2. Surface curing of pH and electric field responsive hydrogel and the application to drug delivery systems. Electrolyte monomers such as acrylic acid was coated on the surface of polymer membrane (porous or non-porous) including drugs, and cured by UV or radiation various enzymes were immobilized in the coating layer in many cases. The product showed pH, electro-field and substrate responsive releases of model drug under on-off switching of environmental conditions. (J.P.N.)

  20. Synthesis and application of intelligent hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Kaetsu, I.; Uchida, K.; Sutani, K.; Nakayama, H.; Tamori, A. [Kinki Univ., Higashi-Osaka, Osaka (Japan). Faculty of Science and Technology

    2000-03-01

    The authors have studied synthesis and application of stimule-sensitive and responsive hydrogels. In this report, two kinds of investigations were carried out on the intelligent hydrogels and the applications with radiation techniques. 1. Synthesis of temperature responsive sol-gel transition polymer and the application to drug delivery systems. Polysopropyl acrylamide is a typical temperature responsive polymers and the copolymers show broad variation of LCST (sol-gel transition temperature). The various copolymers of isopropyl acrylamide were synthesized by UV or radiation. 2. Surface curing of pH and electric field responsive hydrogel and the application to drug delivery systems. Electrolyte monomers such as acrylic acid was coated on the surface of polymer membrane (porous or non-porous) including drugs, and cured by UV or radiation various enzymes were immobilized in the coating layer in many cases. The product showed pH, electro-field and substrate responsive releases of model drug under on-off switching of environmental conditions. (J.P.N.)

  1. Degradation of chitosan-based materials after different sterilization treatments

    International Nuclear Information System (INIS)

    San Juan, A; Montembault, A; Royaud, I; David, L; Gillet, D; Say, J P; Rouif, S; Bouet, T

    2012-01-01

    Biopolymers have received in recent years an increasing interest for their potential applications in the field of biomedical engineering. Among the natural polymers that have been experimented, chitosan is probably the most promising in view of its exceptional biological properties. Several techniques may be employed to sterilize chitosan-based materials. The aim of our study was to compare the effect of common sterilization treatments on the degradation of chitosan-based materials in various physical states: solutions, hydrogels and solid flakes. Four sterilization methods were compared: gamma irradiation, beta irradiation, exposure to ethylene oxide and saturated water steam sterilization (autoclaving). Exposure to gamma or beta irradiation was shown to induce an important degradation of chitosan, regardless of its physical state. The chemical structure of chitosan flakes was preserved after ethylene oxide sterilization, but this technique has a limited use for materials in the dry state. Saturated water steam sterilization of chitosan solutions led to an important depolymerization. Nevertheless, steam sterilization of chitosan flakes bagged or dispersed in water was found to preserve better the molecular weight of the polymer. Hence, the sterilization of chitosan flakes dispersed in water would represent an alternative step for the preparation of sterilized chitosan solutions. Alternatively, autoclaving chitosan physical hydrogels did not significantly modify the macromolecular structure of the polymer. Thus, this method is one of the most convenient procedures for the sterilization of physical chitosan hydrogels after their preparation.

  2. On the Interaction between Superabsorbent Hydrogels and Cementitious Materials

    Science.gov (United States)

    Farzanian, Khashayar

    Autogenous shrinkage induced cracking is a major concern in high performance concretes (HPC), which are produced with low water to cement ratios. Internal curing to maintain high relative humidity in HPC with the use of an internal water reservoir has proven effective in mitigating autogenous shrinkage in HPC. Superabsorbent polymers (SAP) or hydrogels have received increasing attention as an internal curing agent in recent years. A key advantage of SAP is its versatility in size distribution and absorption/desorption characteristics, which allow it to be adapted to specific mix designs. Understanding the behavior of superabsorbent hydrogels in cementitious materials is critical for accurate design of internal curing. The primary goal of this study is to fundamentally understand the interaction between superabsorbent hydrogels and cementitious materials. In the first step, the effect of chemical and mechanical conditions on the absorption of hydrogels is investigated. In the second step, the desorption of hydrogels in contact with porous cementitious materials is examined to aid in understanding the mechanisms of water release from superabsorbent hydrogels (SAP) into cementitious materials. The dependence of hydrogel desorption on the microstructure of cementitious materials and relative humidity is studied. It is shown that the capillary forces developed at the interface between the hydrogel and cementitious materials increased the desorption of the hydrogels. The size of hydrogels is shown to influence desorption, beyond the known size dependence of bulk diffusion, through debonding from the cementitious matrix, thereby decreasing the effect of the Laplace pressure on desorption. In the third step, the desorption of hydrogels synthesized with varied chemical compositions in cementitious materials are investigated. The absorption, chemical structure and mechanical response of hydrogels swollen in a cement mixture are studied. The effect of the capillary forces on

  3. Lima Bean Starch-Based Hydrogels | Oladebeye | Nigerian Journal ...

    African Journals Online (AJOL)

    Hydrogels were prepared by crosslinking native lima bean starch and polyvinyl alcohol (PVA) with glutaraldehyde (GA) at varying proportions in an acidic medium. The native starch (N-LBS) and hydrogels (L-GA (low glutaraldehyde) and H-GA (high glutaraldehyde)) were examined for their water absorption capacity (WAC) ...

  4. Keratin sponge/hydrogel II, active agent delivery

    Science.gov (United States)

    Keratin sponge/hydrogels from oxidation and reduction hydrolysis of fine and coarse wool fibers were formed to behave as cationic hydrogels to swell and release active agents in the specific region of the gastro-intestinal (GI) tract. Their porous, interpenetrating networks (IPN) were effective for...

  5. Artificial Auricular Cartilage Using Silk Fibroin and Polyvinyl Alcohol Hydrogel

    Science.gov (United States)

    Lee, Jung Min; Sultan, Md. Tipu; Kim, Soon Hee; Kumar, Vijay; Yeon, Yeung Kyu; Lee, Ok Joo; Park, Chan Hum

    2017-01-01

    Several methods for auricular cartilage engineering use tissue engineering techniques. However, an ideal method for engineering auricular cartilage has not been reported. To address this issue, we developed a strategy to engineer auricular cartilage using silk fibroin (SF) and polyvinyl alcohol (PVA) hydrogel. We constructed different hydrogels with various ratios of SF and PVA by using salt leaching, silicone mold casting, and freeze-thawing methods. We characterized each of the hydrogels in terms of the swelling ratio, tensile strength, pore size, thermal properties, morphologies, and chemical properties. Based on the cell viability results, we found a blended hydrogel composed of 50% PVA and 50% SF (P50/S50) to be the best hydrogel among the fabricated hydrogels. An intact 3D ear-shaped auricular cartilage formed six weeks after the subcutaneous implantation of a chondrocyte-seeded 3D ear-shaped P50/S50 hydrogel in rats. We observed mature cartilage with a typical lacunar structure both in vitro and in vivo via histological analysis. This study may have potential applications in auricular tissue engineering with a human ear-shaped hydrogel. PMID:28777314

  6. Functionalized graphene hydrogel-based high-performance supercapacitors.

    Science.gov (United States)

    Xu, Yuxi; Lin, Zhaoyang; Huang, Xiaoqing; Wang, Yang; Huang, Yu; Duan, Xiangfeng

    2013-10-25

    Functionalized graphene hydrogels are prepared by a one-step low-temperature reduction process and exhibit ultrahigh specific capacitances and excellent cycling stability in the aqueous electrolyte. Flexible solid-state supercapacitors based on functionalized graphene hydrogels are demonstrated with superior capacitive performances and extraordinary mechanical flexibility. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Lab-on-a-chip devices with patterned hydrogels

    NARCIS (Netherlands)

    Gümüscü, B.

    2016-01-01

    Hydrogels are considered to be in the class of smart materials that find application in diagnostic, therapeutic,and fundamental science tools for miniaturized total analysis systems. In this thesis, the focus is on three major applications of patterned hydrogels, which are explored as an alternative

  8. initiated small intestinal sub-mucosal wound-healing hydrogel

    African Journals Online (AJOL)

    In vitro cell culture was carried out on the hydrogels, and cell count was obtained on ... a crucial role in stem cell differentiation. ... biodegradable material, especially in tissue engineering [10,11]. .... The test procedures used were based on the method of ..... responsive hydrogels for controlled drug release. Polymer. 2009 ...

  9. Volume changes in hydrogels subjected to finite deformations

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville

    2013-01-01

    Constitutive equations are derived for the elastic response of hydrogels under an arbitrary deformationwith finite strains. An expression is proposed for the free energy density of a hydrogel based on the Floryconcept of a network of flexible chains with constrained junctions whose reference conf...

  10. Hydrogel-based sensor for CO2 measurements

    NARCIS (Netherlands)

    Herber, S.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2004-01-01

    A hydrogel-based sensor is presented for CO2 measurements. The sensor consists of a pressure sensor and porous silicon cover. A pH-sensitive hydrogel is confined between the two parts. Furthermore the porous cover contains a bicarbonate solution and a gaspermeable membrane. CO2 reacts with the

  11. Reinforcement of hydrogels using three-dimensionally printed microfibres

    NARCIS (Netherlands)

    Visser, Jetze; Melchels, Ferry P. W.; Jeon, June E.; van Bussel, Erik M.; Kimpton, Laura S.; Byrne, Helen M.; Dhert, Wouter J. A.; Dalton, Paul D.; Hutmacher, Dietmar W.; Malda, J

    Despite intensive research, hydrogels currently available for tissue repair in the musculoskeletal system are unable to meet the mechanical, as well as the biological, requirements for successful outcomes. Here we reinforce soft hydrogels with highly organized, high-porosity microfibre networks that

  12. Two-component thermosensitive hydrogels : Phase separation affecting rheological behavior

    NARCIS (Netherlands)

    Abbadessa, Anna; Landín, Mariana; Oude Blenke, Erik; Hennink, Wim E.; Vermonden, Tina

    2017-01-01

    Extracellular matrices are mainly composed of a mixture of different biopolymers and therefore the use of two or more building blocks for the development of tissue-mimicking hydrogels is nowadays an attractive strategy in tissue-engineering. Multi-component hydrogel systems may undergo phase

  13. Extracellular matrix hydrogels from decellularized tissues: Structure and function.

    Science.gov (United States)

    Saldin, Lindsey T; Cramer, Madeline C; Velankar, Sachin S; White, Lisa J; Badylak, Stephen F

    2017-02-01

    Extracellular matrix (ECM) bioscaffolds prepared from decellularized tissues have been used to facilitate constructive and functional tissue remodeling in a variety of clinical applications. The discovery that these ECM materials could be solubilized and subsequently manipulated to form hydrogels expanded their potential in vitro and in vivo utility; i.e. as culture substrates comparable to collagen or Matrigel, and as injectable materials that fill irregularly-shaped defects. The mechanisms by which ECM hydrogels direct cell behavior and influence remodeling outcomes are only partially understood, but likely include structural and biological signals retained from the native source tissue. The present review describes the utility, formation, and physical and biological characterization of ECM hydrogels. Two examples of clinical application are presented to demonstrate in vivo utility of ECM hydrogels in different organ systems. Finally, new research directions and clinical translation of ECM hydrogels are discussed. More than 70 papers have been published on extracellular matrix (ECM) hydrogels created from source tissue in almost every organ system. The present manuscript represents a review of ECM hydrogels and attempts to identify structure-function relationships that influence the tissue remodeling outcomes and gaps in the understanding thereof. There is a Phase 1 clinical trial now in progress for an ECM hydrogel. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Biochemical analyses of lipids deposited on silicone hydrogel lenses

    Directory of Open Access Journals (Sweden)

    Shin Hatou

    2010-07-01

    Conclusions: The quantity of total lipid and cholesterol deposited on the 3 silicone hydrogel lenses tested did not differ. However, there were significant differences in the amounts of phospholipid deposited among the 3 silicone hydrogel lenses, of which clinical significance should be explored in the future study.

  15. The matrix reloaded: the evolution of regenerative hydrogels

    NARCIS (Netherlands)

    Jabbari, E.; Leijten, Jeroen Christianus Hermanus; Xu, Q.; Khademhosseini, A.

    2016-01-01

    Cell-laden hydrogels can regenerate lost, damaged or malfunctioning tissues. Clinical success of such hydrogels is strongly dependent on the ability to tune their chemical, physico-mechanical, and biological properties to a specific application. In particular, mimicking the intricate arrangement of

  16. Nanoreinforced biocompatible hydrogels from wood hemicelluloses and cellulose whiskers

    Science.gov (United States)

    Muzaffer Ahmet Karaaslan; Mandla A. Tshabalala; Daniel J. Yelle; Gisela Buschle-Diller

    2011-01-01

    Nanoreinforced hydrogels with a unique network structure were prepared from wood cellulose whiskers coated with chemically modified wood hemicelluloses. The hemicelluloses were modified with 2-hydroxyethylmethacrylate prior to adsorption onto the cellulose whiskers in aqueous medium. Synthesis of the hydrogels was accomplished by in situ radical polymerization of the...

  17. An ultra melt-resistant hydrogel from food grade carbohydrates

    NARCIS (Netherlands)

    Thompson, Benjamin R.; Horozov, Tommy S.; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2017-01-01

    We report a binary hydrogel system made from two food grade biopolymers, agar and methylcellulose (agar-MC), which does not require addition of salt for gelation to occur and has very unusual rheological and thermal properties. It is found that the storage modulus of the agar-MC hydrogel far

  18. Biocompatibility of hydrogel-based scaffolds for tissue engineering applications.

    Science.gov (United States)

    Naahidi, Sheva; Jafari, Mousa; Logan, Megan; Wang, Yujie; Yuan, Yongfang; Bae, Hojae; Dixon, Brian; Chen, P

    2017-09-01

    Recently, understanding of the extracellular matrix (ECM) has expanded rapidly due to the accessibility of cellular and molecular techniques and the growing potential and value for hydrogels in tissue engineering. The fabrication of hydrogel-based cellular scaffolds for the generation of bioengineered tissues has been based on knowledge of the composition and structure of ECM. Attempts at recreating ECM have used either naturally-derived ECM components or synthetic polymers with structural integrity derived from hydrogels. Due to their increasing use, their biocompatibility has been questioned since the use of these biomaterials needs to be effective and safe. It is not surprising then that the evaluation of biocompatibility of these types of biomaterials for regenerative and tissue engineering applications has been expanded from being primarily investigated in a laboratory setting to being applied in the multi-billion dollar medicinal industry. This review will aid in the improvement of design of non-invasive, smart hydrogels that can be utilized for tissue engineering and other biomedical applications. In this review, the biocompatibility of hydrogels and design criteria for fabricating effective scaffolds are examined. Examples of natural and synthetic hydrogels, their biocompatibility and use in tissue engineering are discussed. The merits and clinical complications of hydrogel scaffold use are also reviewed. The article concludes with a future outlook of the field of biocompatibility within the context of hydrogel-based scaffolds. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Multi-scale Multi-mechanism Toughening of Hydrogels

    Science.gov (United States)

    Zhao, Xuanhe

    Hydrogels are widely used as scaffolds for tissue engineering, vehicles for drug delivery, actuators for optics and fluidics, and model extracellular matrices for biological studies. The scope of hydrogel applications, however, is often severely limited by their mechanical properties. Inspired by the mechanics and hierarchical structures of tough biological tissues, we propose that a general principle for the design of tough hydrogels is to implement two mechanisms for dissipating mechanical energy and maintaining high elasticity in hydrogels. A particularly promising strategy for the design is to integrate multiple pairs of mechanisms across multiple length scales into a hydrogel. We develop a multiscale theoretical framework to quantitatively guide the design of tough hydrogels. On the network level, we have developed micro-physical models to characterize the evolution of polymer networks under deformation. On the continuum level, we have implemented constitutive laws formulated from the network-level models into a coupled cohesive-zone and Mullins-effect model to quantitatively predict crack propagation and fracture toughness of hydrogels. Guided by the design principle and quantitative model, we will demonstrate a set of new hydrogels, based on diverse types of polymers, yet can achieve extremely high toughness superior to their natural counterparts such as cartilages. The work was supported by NSF(No. CMMI- 1253495) and ONR (No. N00014-14-1-0528).

  20. Hydrogels Prepared from Cross-Linked Nanofibrillated Cellulose

    Science.gov (United States)

    Sandeep S. Nair; J.Y. Zhu; Yulin Deng; Arthur J. Ragauskas

    2014-01-01

    Nanocomposite hydrogels were developed by cross-linking nanofibrillated cellulose with poly(methyl vinyl ether-co-maleic acid) and polyethylene glycol. The cross-linked hydrogels showed enhanced water absorption and gel content with the addition of nanocellulose. In addition, the thermal stability, mechanical strength, and modulus increased with an increase in the...

  1. Radiation-chemical preparation of poly(vinyl alcohol) hydrogels

    International Nuclear Information System (INIS)

    Duflot, Anastasia V.; Kitaeva, Natalia K.; Duflot, Vladimir R.

    2015-01-01

    This work reports the usage of method of radiation-chemical synthesis to prepare cross-linked hydrogels from poly(vinyl alcohol) modified with glycidyl methacrylate. Synthesis kinetics of modified poly(vinyl alcohol) and properties of hydrogels were studied. The gel fraction, swelling, mechanical properties, and water content of the hydrogels were measured. It was found that gel fraction increases with increasing radiation dose, concentration of modified poly(vinyl alcohol), and reaches 60%. It was established by differential scanning calorimetry that a fraction of the “bound” water in hydrogels is 50–70% and independent of gel fraction content. In addition to “bound” and “free” states, water in hydrogels is also present in the intermediate state. - Highlights: • The synthesis and the properties of poly(vinyl alcohol) hydrogels were studied. • PVA was modified by glycidyl methacrylate before gamma cross-linking. • The modification results in decreasing of PVA cross-linking dose by 3 orders lower. • The gel fraction and water content of the hydrogels were measured. • A fraction of the “bound” water in hydrogels is independent of gel fraction content

  2. Computational Study of pH-sensitive Hydrogel-based Microfluidic Flow Controllers

    Science.gov (United States)

    Kurnia, Jundika C.; Birgersson, Erik; Mujumdar, Arun S.

    2011-01-01

    This computational study investigates the sensing and actuating behavior of a pH-sensitive hydrogel-based microfluidic flow controller. This hydrogel-based flow controller has inherent advantage in its unique stimuli-sensitive properties, removing the need for an external power supply. The predicted swelling behavior the hydrogel is validated with steady-state and transient experiments. We then demonstrate how the model is implemented to study the sensing and actuating behavior of hydrogels for different microfluidic flow channel/hydrogel configurations: e.g., for flow in a T-junction with single and multiple hydrogels. In short, the results suggest that the response of the hydrogel-based flow controller is slow. Therefore, two strategies to improve the response rate of the hydrogels are proposed and demonstrated. Finally, we highlight that the model can be extended to include other stimuli-responsive hydrogels such as thermo-, electric-, and glucose-sensitive hydrogels. PMID:24956303

  3. Classification, processing and application of hydrogels: A review.

    Science.gov (United States)

    Ullah, Faheem; Othman, Muhammad Bisyrul Hafi; Javed, Fatima; Ahmad, Zulkifli; Md Akil, Hazizan

    2015-12-01

    This article aims to review the literature concerning the choice of selectivity for hydrogels based on classification, application and processing. Super porous hydrogels (SPHs) and superabsorbent polymers (SAPs) represent an innovative category of recent generation highlighted as an ideal mould system for the study of solution-dependent phenomena. Hydrogels, also termed as smart and/or hungry networks, are currently subject of considerable scientific research due to their potential in hi-tech applications in the biomedical, pharmaceutical, biotechnology, bioseparation, biosensor, agriculture, oil recovery and cosmetics fields. Smart hydrogels display a significant physiochemical change in response to small changes in the surroundings. However, such changes are reversible; therefore, the hydrogels are capable of returning to its initial state after a reaction as soon as the trigger is removed. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Preparation and characterization of bioglass/polyvinyl alcohol composite hydrogel

    International Nuclear Information System (INIS)

    Xu Hong; Wang Yingjun; Zheng Yudong; Chen Xiaofeng; Ren Li; Wu Gang; Huang Xiaoshan

    2007-01-01

    In order to form firm active fixation with the adjacent bone, a new kind of bioactive composite hydrogel was prepared with polyvinyl alcohol (PVA) and bioglass (BG) through ultrasonic dispersion, heat-high-pressure and freeze/thawed technique. A digital speckle correlation method (DSCM) was utilized to characterize the mechanical properties of the series of BG/PVA composites. Results showed that at different load pressures, the composite hydrogel displayed different displacement and deformation in the V field. Results also showed that an increase of PVA percentage (15-30 wt%) or of bioglass percentage (2-10 wt%) in composite hydrogel could lead to an increase in the elastic compression modulus. Scanning electron microscope results indicated that bioglass was uniformly dispersed in the BG/PVA composite hydrogel. The BG/PVA composite hydrogel shows a promising prospect as a new bionic cartilage implantation material

  5. Development of sago starch hydrogel for wound dressing

    Energy Technology Data Exchange (ETDEWEB)

    Kamaruddin Hashim; Khairul Zaman HJ. Mohd Dahlan; Kamarudin Bahari [Malaysian Institute for Nuclear Technology Research (MINT), Bangi (Malaysia); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Sago starch is utilized in Malaysia mainly for food production. The purpose of the research is to diversify the use of sago starch for medical application particularly in development of hydrogel burn wound dressing. The sago starch is blending with mixture of PVP and PVA to improve the degree of crosslink, mechanical properties, swelling ability and tackiness of the blend hydrogel (sago/PVA and sago PVP). Additives have been introduced into the system such as, polypropylene glycol or carboxymethyl cellulose to improved further the swelling ability and tackiness properties of the blend hydrogel as well as other properties. Effect of irradiation dose on the blend hydrogel has also been studied to optimize the effective dose for blend hydrogel and simultaneously for sterilization purpose. (author)

  6. Engineering three-dimensional cell mechanical microenvironment with hydrogels.

    Science.gov (United States)

    Huang, Guoyou; Wang, Lin; Wang, Shuqi; Han, Yulong; Wu, Jinhui; Zhang, Qiancheng; Xu, Feng; Lu, Tian Jian

    2012-12-01

    Cell mechanical microenvironment (CMM) significantly affects cell behaviors such as spreading, migration, proliferation and differentiation. However, most studies on cell response to mechanical stimulation are based on two-dimensional (2D) planar substrates, which cannot mimic native three-dimensional (3D) CMM. Accumulating evidence has shown that there is a significant difference in cell behavior in 2D and 3D microenvironments. Among the materials used for engineering 3D CMM, hydrogels have gained increasing attention due to their tunable properties (e.g. chemical and mechanical properties). In this paper, we provide an overview of recent advances in engineering hydrogel-based 3D CMM. Effects of mechanical cues (e.g. hydrogel stiffness and externally induced stress/strain in hydrogels) on cell behaviors are described. A variety of approaches to load mechanical stimuli in 3D hydrogel-based constructs are also discussed.

  7. Advances in the Fabrication of Antimicrobial Hydrogels for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Carmen M. González-Henríquez

    2017-02-01

    Full Text Available This review describes, in an organized manner, the recent developments in the elaboration of hydrogels that possess antimicrobial activity. The fabrication of antibacterial hydrogels for biomedical applications that permits cell adhesion and proliferation still remains as an interesting challenge, in particular for tissue engineering applications. In this context, a large number of studies has been carried out in the design of hydrogels that serve as support for antimicrobial agents (nanoparticles, antibiotics, etc.. Another interesting approach is to use polymers with inherent antimicrobial activity provided by functional groups contained in their structures, such as quaternary ammonium salt or hydrogels fabricated from antimicrobial peptides (AMPs or natural polymers, such as chitosan. A summary of the different alternatives employed for this purpose is described in this review, considering their advantages and disadvantages. Finally, more recent methodologies that lead to more sophisticated hydrogels that are able to react to external stimuli are equally depicted in this review.

  8. Construction of Injectable Double-Network Hydrogels for Cell Delivery.

    Science.gov (United States)

    Yan, Yan; Li, Mengnan; Yang, Di; Wang, Qian; Liang, Fuxin; Qu, Xiaozhong; Qiu, Dong; Yang, Zhenzhong

    2017-07-10

    Herein we present a unique method of using dynamic cross-links, which are dynamic covalent bonding and ionic interaction, for the construction of injectable double-network (DN) hydrogels, with the objective of cell delivery for cartilage repair. Glycol chitosan and dibenzaldhyde capped poly(ethylene oxide) formed the first network, while calcium alginate formed the second one, and in the resultant DN hydrogel, either of the networks could be selectively removed. The moduli of the DN hydrogel were significantly improved compared to that of the parent single-network hydrogels and were tunable by changing the chemical components. In situ 3D cell encapsulation could be easily performed by mixing cell suspension to the polymer solutions and transferred through a syringe needle before sol-gel transition. Cell proliferation and mediated differentiation of mouse chondrogenic cells were achieved in the DN hydrogel extracellular matrix.

  9. Development of sago starch hydrogel for wound dressing

    International Nuclear Information System (INIS)

    Kamaruddin Hashim; Khairul Zaman HJ Mohd Dahlan; Kamarudin Bahari; Yoshii, Fumio; Kume, Tamikazu

    2001-01-01

    Sago starch is utilized in Malaysia mainly for food production. The purpose of the research is to diversify the use of sago starch for medical application particularly in development of hydrogel burn wound dressing. The sago starch is blending with mixture of PVP and PVA to improve the degree of crosslink, mechanical properties, swelling ability and tackiness of the blend hydrogel (sago/PVA and sago PVP). Additives have been introduced into the system such as, polypropylene glycol or carboxymethyl cellulose to improved further the swelling ability and tackiness properties of the blend hydrogel as well as other properties. Effect of irradiation dose on the blend hydrogel has also been studied to optimize the effective dose for blend hydrogel and simultaneously for sterilization purpose. (author)

  10. Engineering three-dimensional cell mechanical microenvironment with hydrogels

    International Nuclear Information System (INIS)

    Huang Guoyou; Wang Lin; Han Yulong; Zhang Qiancheng; Xu Feng; Lu Tianjian; Wang Shuqi; Wu Jinhui

    2012-01-01

    Cell mechanical microenvironment (CMM) significantly affects cell behaviors such as spreading, migration, proliferation and differentiation. However, most studies on cell response to mechanical stimulation are based on two-dimensional (2D) planar substrates, which cannot mimic native three-dimensional (3D) CMM. Accumulating evidence has shown that there is a significant difference in cell behavior in 2D and 3D microenvironments. Among the materials used for engineering 3D CMM, hydrogels have gained increasing attention due to their tunable properties (e.g. chemical and mechanical properties). In this paper, we provide an overview of recent advances in engineering hydrogel-based 3D CMM. Effects of mechanical cues (e.g. hydrogel stiffness and externally induced stress/strain in hydrogels) on cell behaviors are described. A variety of approaches to load mechanical stimuli in 3D hydrogel-based constructs are also discussed. (topical review)

  11. Free radical scavenging injectable hydrogels for regenerative therapy.

    Science.gov (United States)

    Komeri, Remya; Thankam, Finosh Gnanaprakasam; Muthu, Jayabalan

    2017-02-01

    Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Hydrogels That Allow and Facilitate Bone Repair, Remodeling, and Regeneration.

    Science.gov (United States)

    Short, Aaron R; Koralla, Deepthi; Deshmukh, Ameya; Wissel, Benjamin; Stocker, Benjamin; Calhoun, Mark; Dean, David; Winter, Jessica O

    2015-10-28

    Bone defects can originate from a variety of causes, including trauma, cancer, congenital deformity, and surgical reconstruction. Success of the current "gold standard" treatment (i.e., autologous bone grafts) is greatly influenced by insufficient or inappropriate bone stock. There is thus a critical need for the development of new, engineered materials for bone repair. This review describes the use of natural and synthetic hydrogels as scaffolds for bone tissue engineering. We discuss many of the advantages that hydrogels offer as bone repair materials, including their potential for osteoconductivity, biodegradability, controlled growth factor release, and cell encapsulation. We also discuss the use of hydrogels in composite devices with metals, ceramics, or polymers. These composites are useful because of the low mechanical moduli of hydrogels. Finally, the potential for thermosetting and photo-cross-linked hydrogels as three-dimensionally (3D) printed, patient-specific devices is highlighted. Three-dimensional printing enables controlled spatial distribution of scaffold materials, cells, and growth factors. Hydrogels, especially natural hydrogels present in bone matrix, have great potential to augment existing bone tissue engineering devices for the treatment of critical size bone defects.

  13. Radiation Synthesis of Stimuli-Responsive Hydrogels for Biological Applications

    International Nuclear Information System (INIS)

    Eid, M.; Hegazy, S.A.

    2009-01-01

    Poly(acrylamide/maleic acid/gelatin) P(AAm/MA/G) hydrogel networks were synthesized by 60 Co gamma irradiation at different doses. The properties of the hydrogels such as gelation percent, porosity, and moisture retention were investigated. The swelling ratio (S), equilibrium water content (EWC) and diffusion characteristics, including equilibrium swelling ratio (ESR), diffusion constant (n) and diffusion coefficients (D) were investigated and a non-Fickian type of diffusion characteristics was found in all the swelling media for the diffusion of water into these hydrogels. Further, the swelling pattern of P(AAm/MA/G) hydrogels was studied in different physiological bio-fluids, ph and ionic/salt solutions and showed great responsiveness due to their ionic character. The penetration velocity (v) of these biological fluids into such hydrogels was also calculated and it was found to be the maximum in urea and the minimum in synthetic urine. The higher equilibrium water content of these hydrogels, promotes them to be used as biomedical/pharmaceutical technology. The caffeine release as a drug model has been studied at ph 1 and ph 7 to resemble the ph of the stomach and the intestine, respectively. The caffeine release was controlled by the hydrogel crosslinking density that caused in increase of the irradiation dose

  14. Significance of Glucose Addition on Chitosan-Glycerophosphate Hydrogel Properties

    Directory of Open Access Journals (Sweden)

    Dian Susanthy

    2016-03-01

    Full Text Available Chitosan-glycerophosphate hydrogel can be used as dental scaffold due to its thermosensitivity, gelation performance at body temperature, suitable acidity for body condition, biocompatibility, and ability to provide good environment for cell proliferation and differentiation. Previous study showed that glucose addition to the chitosan solution before steam sterilization improved its hydrogel mechanical strength. However, the effectiveness of glucose addition was still doubted because glucose might undergo Maillard reaction in that particular condition. The aims of this study are to confirm whether the glucose addition can increase the hydrogel mechanical strength and gelation rate effectively and also to compare their performance to be dental scaffold. This research was performed through several steps, namely preparation of chitosan-glycerophosphate solution, addition of glucose, gelation time test, gel mechanical strength measurement, functional group analysis, and physical properties measurements (pH, viscosity, and pore size. The result showed that glucose addition did not improve the hydrogel mechanical strength and gelation rate, neither when it was added before nor after steam sterilization. Glucose addition before steam sterilization seemed to trigger Maillard reaction or browning effect, while glucose addition after steam sterilization increased the amount of free water molecules in the hydrogel. Chitosan and glycerophosphate interact physically, but interaction between chitosan and glucose seems to occur chemically and followed by the formation of free water molecules. Glucose addition decreases the solution viscosity and hydrogel pore size so the hydrogel performance as dental scaffold is lowered.

  15. Gamma radiation synthesis of super absorbent hydrogels for different applications

    International Nuclear Information System (INIS)

    Marzouk, H.M.G.

    2015-01-01

    Super absorbent polymers (SAP) of carboxymethyl cellulose/acrylamide (CMC/PAM), carboxymethyl cellulose/acrylamide/Silica (CMC/AM/Si) and carboxymethyl cellulose/Polyvinyl alcohol (CMC/PVA) were synthesized by radiation-induced grafting using γ-irradiation technique. The effects of various parameters, such as irradiation dose, the content of CMC, PAM, PVA, and Silica gel on the swelling percent of produced hydrogels have been evaluated. The kinetic equilibrium swelling of the prepared copolymer hydrogels was studied, it was found that the maximum swelling percent was 5000 % for the CMC/PAM hydrogel, 12000 % for the CMC/PAM/Si composite hydrogel, and 6200 % for the CMC/PVA hydrogel. The gel fraction, equilibrium swelling and effect of ph on the swelling percent were also studied. The prepared copolymers were also characterized by FTIR spectral analysis, thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM) techniques. In order to evaluate its controlled release potential, different prepared hydrogels were loaded with KNO 3 as an agrochemical model and its potential for controlled release of KNO 3 was studied and evaluated with respect to different parameters such as time of release, ph of the medium, and temperatures. The results obtained from swelling, loading of KNO 3 , and release behavior studies suggested and recommended the possible use of prepared hydrogels for enhancing the plantation of Linum Usitatissimum.

  16. A Method for Seawater Desalination via Squeezing Ionic Hydrogels.

    Science.gov (United States)

    Yu, Chi; Wang, Yanhong; Lang, Xuemei; Fan, Shuanshi

    2016-12-06

    In this study, mechanical force applied to squeeze poly(sodium acrylate-co-2-hydroxyethyl methacrylate) hydrogels that contained seawater in order to obtain fresh water. By incorporating ionic monomer sodium acrylate (SA) into hydrogels, the salt rejection was significantly enhanced from 27.62% to 64.57% (feed concentration 35.00g/L NaCl solution). As SA's concentration continuously increased, salt rejection declined due to the change in hydrogel's matrix structure. Therefore, water recovery raised as the current swelling degree increased. We also measured pore size distribution by applying mercury intrusion porosimetry on each hydrogel sample in the interest of finding out whether the sample SA5/HEMA15 owned multi pore structure, since the result could be good for the desalination performance. After 4 times reused, the hydrogel remained good desalination performance. Although compared to reverse osmosis (RO) and multistage flash distillation (MSF) & multiple effect distillation (MED) the salt rejection of this hydrogel (roughly 64%) seemed low, the hydrogels can be used for forward osmosis and reverse osmosis, as pretreatment of seawater to reduce the energy consumption for the downstream.

  17. Role of natural polysaccharides in radiation formation of PVA hydrogel wound dressing

    Science.gov (United States)

    Varshney, Lalit

    2007-02-01

    Radiation processed PVA-polysaccharides hydrogels have been observed to be suitable for producing transparent, flexible, mechanically strong, biocompatible, effective and economical hydrogel dressings. The dressings were formed in single stage irradiation process achieving gel formation and sterilization at 25-30 kGy gamma radiation dose. No synthetic plasticizers and additives were used. Different formulations containing poly-vinylalcohol (PVA) and polysaccharides selected from combinations of agar and carrageenan were used to make the dressings. The selected polysaccharides themselves form thermo-reversible gels and degrade on irradiation. Using concentration of polysaccharides as low as 0.5-2% resulted in increase of tensile strength from 45 g/cm 2 to 411 g/cm 2, elongation from 30% to 410% and water uptake from 25% to 157% with respect to PVA gel without polysaccharides. Besides improving mechanical strength, agar contributes more to elongation and carrageenan to mechanical strength of the gel dressing. PVA formulations containing the polysaccharides show significantly different pre-gel viscosities behaviour. Increasing the concentration of agar in the formulation to about 2% converts the sheet gel to paste gel useful for filling wound cavities. The results indicate that pre irradiation network structure of the formulation plays an important role in determining mechanical properties of the irradiated gel dressing. Formulations containing 7-9% PVA, 0.5-1.5% carrageenan and 0.5-1% agar gave highly effective usable hydrogel dressings. Scanning electron micrographs show highly porous structure of the gel. Clinical trials of wound dressing on human patients established safety and efficacy of the dressing. The dressing has been observed to be useful in treating burns, non-healing ulcers of diabetes, leprosy and other external wounds. The dressings are now being marketed in India under different brand names.

  18. Role of natural polysaccharides in radiation formation of PVA-hydrogel wound dressing

    Energy Technology Data Exchange (ETDEWEB)

    Varshney, Lalit [ISOMED, Radiation Technology Development Section, Radio-Chemistry and Isotope Group, B.A.R.C, Mumbai 400 085 (India)]. E-mail: lalitv@barc.gov.in

    2007-02-15

    Radiation processed PVA-polysaccharides hydrogels have been observed to be suitable for producing transparent, flexible, mechanically strong, biocompatible, effective and economical hydrogel dressings. The dressings were formed in single stage irradiation process achieving gel formation and sterilization at 25-30 kGy gamma radiation dose. No synthetic plasticizers and additives were used. Different formulations containing poly-vinylalcohol (PVA) and polysaccharides selected from combinations of agar and carrageenan were used to make the dressings. The selected polysaccharides themselves form thermo-reversible gels and degrade on irradiation. Using concentration of polysaccharides as low as 0.5-2% resulted in increase of tensile strength from 45 g/cm{sup 2} to 411 g/cm{sup 2}, elongation from 30% to 410% and water uptake from 25% to 157% with respect to PVA gel without polysaccharides. Besides improving mechanical strength, agar contributes more to elongation and carrageenan to mechanical strength of the gel dressing. PVA formulations containing the polysaccharides show significantly different pre-gel viscosities behaviour. Increasing the concentration of agar in the formulation to about 2% converts the sheet gel to paste gel useful for filling wound cavities. The results indicate that pre irradiation network structure of the formulation plays an important role in determining mechanical properties of the irradiated gel dressing. Formulations containing 7-9% PVA, 0.5-1.5% carrageenan and 0.5-1% agar gave highly effective usable hydrogel dressings. Scanning electron micrographs show highly porous structure of the gel. Clinical trials of wound dressing on human patients established safety and efficacy of the dressing. The dressing has been observed to be useful in treating burns, non-healing ulcers of diabetes, leprosy and other external wounds. The dressings are now being marketed in India under different brand names.

  19. A Cooperative Copper Metal-Organic Framework-Hydrogel System Improves Wound Healing in Diabetes.

    Science.gov (United States)

    Xiao, Jisheng; Chen, Siyu; Yi, Ji; Zhang, Hao; Ameer, Guillermo A

    2017-01-05

    Chronic non-healing wounds remain a major clinical challenge that would benefit from the development of advanced, regenerative dressings that promote wound closure within a clinically relevant time frame. The use of copper ions has shown promise in wound healing applications possibly by promoting angiogenesis. However, reported treatments that use copper ions require multiple applications of copper salts or oxides to the wound bed, exposing the patient to potentially toxic levels of copper ions and resulting in variable outcomes. Herein we set out to assess whether copper metal organic framework nanoparticles (HKUST-1 NPs) embedded within an antioxidant thermoresponsive citrate-based hydrogel would decrease copper ion toxicity and accelerate wound healing in diabetic mice. HKUST-1 and poly-(polyethyleneglycol citrate-co- N -isopropylacrylamide) (PPCN) were synthesized and characterized. HKUST-1 NP stability in a protein solution with and without embedding them in PPCN hydrogel was determined. Copper ion release, cytotoxicity, apoptosis, and in vitro migration processes were measured. Wound closure rates and wound blood perfusion were assessed in vivo using the splinted excisional dermal wound diabetic mouse model. HKUST-1 NP disintegrated in protein solution while HKUST-1 NPs embedded in PPCN (H-HKUST-1) were protected from degradation and copper ions were slowly released. Cytotoxicity and apoptosis due to copper ion release were significantly reduced while dermal cell migration in vitro and wound closure rates in vivo were significantly enhanced. In vivo , H-HKUST-1 induced angiogenesis, collagen deposition, and re-epithelialization during wound healing in diabetic mice. These results suggest that a cooperatively stabilized, copper ion-releasing H-HKUST-1 hydrogel is a promising innovative dressing for the treatment of chronic wounds.

  20. Role of natural polysaccharides in radiation formation of PVA-hydrogel wound dressing

    International Nuclear Information System (INIS)

    Varshney, Lalit

    2007-01-01

    Radiation processed PVA-polysaccharides hydrogels have been observed to be suitable for producing transparent, flexible, mechanically strong, biocompatible, effective and economical hydrogel dressings. The dressings were formed in single stage irradiation process achieving gel formation and sterilization at 25-30 kGy gamma radiation dose. No synthetic plasticizers and additives were used. Different formulations containing poly-vinylalcohol (PVA) and polysaccharides selected from combinations of agar and carrageenan were used to make the dressings. The selected polysaccharides themselves form thermo-reversible gels and degrade on irradiation. Using concentration of polysaccharides as low as 0.5-2% resulted in increase of tensile strength from 45 g/cm 2 to 411 g/cm 2 , elongation from 30% to 410% and water uptake from 25% to 157% with respect to PVA gel without polysaccharides. Besides improving mechanical strength, agar contributes more to elongation and carrageenan to mechanical strength of the gel dressing. PVA formulations containing the polysaccharides show significantly different pre-gel viscosities behaviour. Increasing the concentration of agar in the formulation to about 2% converts the sheet gel to paste gel useful for filling wound cavities. The results indicate that pre irradiation network structure of the formulation plays an important role in determining mechanical properties of the irradiated gel dressing. Formulations containing 7-9% PVA, 0.5-1.5% carrageenan and 0.5-1% agar gave highly effective usable hydrogel dressings. Scanning electron micrographs show highly porous structure of the gel. Clinical trials of wound dressing on human patients established safety and efficacy of the dressing. The dressing has been observed to be useful in treating burns, non-healing ulcers of diabetes, leprosy and other external wounds. The dressings are now being marketed in India under different brand names

  1. Studies on Radiation Synthesis of Poly(vinyl alcohol)- Natural Polysaccharides Hydrogel Wound Dressing

    International Nuclear Information System (INIS)

    Varshney, L.

    2006-01-01

    Radiation processed PVA-polysaccharides hydrogels have been observed to be suitable for producing transparent, flexible and mechanically strong, biocompatible, effective and economical hydrogel dressings(HD). The dressings were formed in single stage irradiation process achieving gel formation and sterilization at 25-30 kGy gamma radiation dose. No synthetic plasticizers and additives were used. Different formulations containing Poly-vinylalcohol, (PVA) and polysaccharides selected from combinations of agar and carrageenan were used to make the dressings. The selected polysaccharides themselves form thermo-reversible gels and degrade on irradiation. Using concentration of polysaccharides as low as 0.5 -2 % resulted in increase of tensile strength from 45 g/cm 2 to 400 g/cm 2 , elongation from 30 % to 410 % and water uptake from 25 % to 120% with respect to PVA gel without polysaccharides. Besides improving mechanical strength, agar contributes more to elongation and carrageenan to mechanical strength of the gel dressing. The polysaccharides show different pre-gel viscosities behaviour indicating different individual contribution to the PVA network. Increasing the concentration of agar in the formulation to about 2% converts the sheet gel to paste gel useful for filling wound cavities. The polysaccharides also provide desirable plasticizer and humectant effect into the dressing. Formulations containing 7-9% PVA, 0.5- 1.5 % carrageenan and 0.5-1% agar gave highly effective usable hydrogel dressings. Scanning Electron Micrographs show highly porous structure of the gel. Clinical trials of wound dressing on human patients established safety and efficacy of the dressing. The dressing has been observed to be useful in treating burns, non healing ulcers of Diabetes, Leprosy and other external wounds. The dressings are now being marketed in India under different brand names

  2. Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

    International Nuclear Information System (INIS)

    Jiang, Huixin; Kobayashi, Takaomi

    2017-01-01

    Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm 3 ) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm 3 of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

  3. Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Huixin; Kobayashi, Takaomi, E-mail: takaomi@nagaokaut.ac.jp

    2017-06-01

    Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm{sup 3}) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm{sup 3} of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

  4. Poly (vinyl alcohol-alginate physically crosslinked hydrogel membranes for wound dressing applications: Characterization and bio-evaluation

    Directory of Open Access Journals (Sweden)

    Elbadawy A. Kamoun

    2015-01-01

    Full Text Available PVA-sodium alginate (SA hydrogel membranes containing sodium ampicillin as a topical antibiotic were developed using the freeze–thawing method for wound dressing application. Aqueous solution of sodium alginate has been blended in a certain ratio with PVA, followed by the crosslinking method has been conducted by freeze–thawing method as physical crosslinking instead of the use of traditional chemical crosslinking to avoid riskiness of chemical reagents and crosslinkers. The physicochemical properties of PVA-SA membranes e.g. gel fraction and water uptake % have been performed. Increased SA content with PVA decreased gel fraction, elasticity, and elongation to break of PVA-SA membranes. However, it resulted in an increase in swelling degree, protein adsorption, and roughness of membrane surface. High SA content in PVA membranes had apparently an impact on surface morphology structure of hydrogel membranes. Pore size and pore area distribution have been observed with addition of high SA concentration. However, high SA content had an insignificant effect on the release of ampicillin. The hydrolytic degradation of PVA-SA membranes has prominently increased with increasing SA content. Furthermore, hemolysis (% and in vitro inhibition (% for both Gram positive and negative bacteria have been sharply affected by addition of SA into PVA, indicating the improved blood hemocompatibility. Thus, PVA-SA hydrogel membrane based wound dressing system containing ampicillin could be a good polymeric membrane candidate in wound care.

  5. Heparin-Poloxamer Thermosensitive Hydrogel Loaded with bFGF and NGF Enhances Peripheral Nerve Regeneration in Diabetic Rats.

    Science.gov (United States)

    Li, Rui; Li, Yiyang; Wu, Yanqing; Zhao, Yingzheng; Chen, Huanwen; Yuan, Yuan; Xu, Ke; Zhang, Hongyu; Lu, Yingfeng; Wang, Jian; Li, Xiaokun; Jia, Xiaofeng; Xiao, Jian

    2018-06-01

    Peripheral nerve injury (PNI) is a major burden to society with limited therapeutic options, and novel biomaterials have great potential for shifting the current paradigm of treatment. With a rising prevalence of chronic illnesses such as diabetes mellitus (DM), treatment of PNI is further complicated, and only few studies have proposed therapies suitable for peripheral nerve regeneration in DM. To provide a supportive environment to restore structure and/or function of nerves in DM, we developed a novel thermo-sensitive heparin-poloxamer (HP) hydrogel co-delivered with basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) in diabetic rats with sciatic nerve crush injury. The delivery vehicle not only had a good affinity for large amounts of growth factors (GFs), but also controlled their release in a steady fashion, preventing degradation in vitro. In vivo, compared with HP hydrogel alone or direct GFs administration, GFs-HP hydrogel treatment is more effective at facilitating Schwann cell (SC) proliferation, leading to an increased expression of nerve associated structural proteins, enhanced axonal regeneration and remyelination, and improved recovery of motor function (all p nerve regeneration in patients with DM. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Physically crosslinked poly(vinyl alcohol-hydroxyethyl starch blend hydrogel membranes: Synthesis and characterization for biomedical applications

    Directory of Open Access Journals (Sweden)

    El-Refaie Kenawy

    2014-07-01

    Full Text Available Poly(vinyl alcohol, PVA is a polymer of great importance because of its many appealing characteristics specifically for various pharmaceutical and biomedical applications. Physically crosslinked hydrogel membranes composed of different amounts of hydroxyethyl starch (HES in (PVA and ampicillin were prepared by applying freeze–thawing method. This freezing–thawing cycle was repeated for three consecutive cycles. Physicochemical properties of PVA–HES membrane gel such as gel fraction, swelling, morphology, elongation, tensile strength, and protein adsorption were investigated. Introducing HES into freeze–thawed PVA structure affected crystal size distribution of PVA; and hence physicochemical properties and morphological structure have been affected. Increased HES concentration decreased the gel fraction %, maximum strength and break elongation. Indeed it resulted into a significant incrementing of the swelling ability, amount of protein adsorption, broader pore size, and pore distribution of membrane morphological structure. Furthermore, an increase in HES concentration resulted in better and still lower thermal stability compared to virgin PVA and freeze–thawed PVA. The maximum weight loss of PVA–HES hydrogel membranes ranged between 18% and 60% according to HES content, after two days of degradation in phosphate buffer saline (PBS, which indicates they are biodegradable. Thus, PVA–HES hydrogel membranes containing ampicillin could be a novel approach for biomedical application e.g. wound dressing purposes.

  7. Microscale Strategies for Generating Cell-Encapsulating Hydrogels

    Directory of Open Access Journals (Sweden)

    Ali Khademhosseini

    2012-09-01

    Full Text Available Hydrogels in which cells are encapsulated are of great potential interest for tissue engineering applications. These gels provide a structure inside which cells can spread and proliferate. Such structures benefit from controlled microarchitectures that can affect the behavior of the enclosed cells. Microfabrication-based techniques are emerging as powerful approaches to generate such cell-encapsulating hydrogel structures. In this paper we introduce common hydrogels and their crosslinking methods and review the latest microscale approaches for generation of cell containing gel particles. We specifically focus on microfluidics-based methods and on techniques such as micromolding and electrospinning.

  8. Manual of radiation processing of cassava starch hydrogel

    International Nuclear Information System (INIS)

    Sonsuk, Manit

    2007-01-01

    The radiation processing of natural cassava starch (CS) is described for the improvement of its properties. A series of hydrogels were prepared from gelatinized CS and vinylpyrrolidone by radiation-induced graft copolymerization. Hydrogels were also synthesized from radiation-induced crosslinking of carboxymethyl CS. The optimum condition for the swelling ratio and gel fraction of the obtained hydrogels is irradiation at low dose. The polymeric chelating resins containing the hydroxamic acid groups were synthesized from the polymethyl acrylate (PMA)-grafted CS via gamma radiation. (M.H.)

  9. Glucose-Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid.

    Science.gov (United States)

    Yetisen, Ali K; Jiang, Nan; Fallahi, Afsoon; Montelongo, Yunuen; Ruiz-Esparza, Guillermo U; Tamayol, Ali; Zhang, Yu Shrike; Mahmood, Iram; Yang, Su-A; Kim, Ki Su; Butt, Haider; Khademhosseini, Ali; Yun, Seok-Hyun

    2017-04-01

    Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide-co-poly(ethylene glycol) diacrylate) cores functionalized with phenylboronic acid. The complexation of the phenylboronic acid and cis-diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. ph Sensitive hydrogel as colon specific drug delivery

    International Nuclear Information System (INIS)

    Alarifi, A.S.

    2011-01-01

    γ-radiation induced graft copolymerization and crosslinking was for the synthesis of ph-sensitive hydrogels composed of poly (vinyl pyrrolidone) acrylic acid. The prepared hydrogels were subjected to swelling test to evaluate the effects of ph and ionic strength of the surrounding solution. Drastic changes in the swelling parameters where observed by changing the surrounding solution ph values. The release of ibuprofen from hydrogels was monitored as a function of time at ph 1 and ph 7 in order to evaluate the prepared copolymer ability for colon- specific drug carrier uses.

  11. Temporally controlled growth factor delivery from a self-assembling peptide hydrogel and electrospun nanofibre composite scaffold.

    Science.gov (United States)

    Bruggeman, Kiara F; Wang, Yi; Maclean, Francesca L; Parish, Clare L; Williams, Richard J; Nisbet, David R

    2017-09-21

    Tissue-specific self-assembling peptide (SAP) hydrogels designed based on biologically relevant peptide sequences have great potential in regenerative medicine. These materials spontaneously form 3D networks of physically assembled nanofibres utilising non-covalent interactions. The nanofibrous structure of SAPs is often compared to that of electrospun scaffolds. These electrospun nanofibers are produced as sheets that can be engineered from a variety of polymers that can be chemically modified to incorporate many molecules including drugs and growth factors. However, their macroscale morphology limits them to wrapping and bandaging applications. Here, for the first time, we combine the benefits of these systems to describe a two-component composite scaffold from these biomaterials, with the design goal of providing a hydrogel scaffold that presents 3D structures, and also has temporal control over drug delivery. Short fibres, cut from electrospun scaffolds, were mixed with our tissue-specific SAP hydrogel to provide a range of nanofibre sizes found in the extracellular matrix (10-300 nm in diameter). The composite material maintained the shear-thinning and void-filling properties of SAP hydrogels that have previously been shown to be effective for minimally invasive material injection, cell delivery and subsequent in vivo integration. Both scaffold components were separately loaded with growth factors, important signaling molecules in tissue regeneration whose rapid degradation limits their clinical efficacy. The two biomaterials provided sequential growth factor delivery profiles: the SAP hydrogel provided a burst release, with the release rate decreasing over 12 hours, while the electrospun nanofibres provided a more constant, sustained delivery. Importantly, this second release commenced 6 days later. The design rules established here to provide temporally distinct release profiles can enable researchers to target specific stages in regeneration, such as the

  12. Radiation crosslinking of starch/water-soluble polymer blends for hydrogel

    International Nuclear Information System (INIS)

    Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z.

    2000-01-01

    Water-soluble polymers such as PVP(polyvinyl pyrrolidone) and PVA(polyvinyl alcohol), in aqueous solution can form hydrogel easily upon gamma or electron beam irradiation. The properties of hydrogels, particularly for wound dressing application, can be further improved by adding sago starch to the blend. Results show improved gel strength and elongation properties of the hydrogel with increasing sago concentration. It was found that the PVA/sago hydrogel gives better gel strength and elongation than the PVP/sago hydrogel. The tackiness property of the PVA/sago hydrogel increased with increase amount of sago starch added. In case of PVP/sago hydrogel, the tackiness property shows significant increase with increasing amount of sago except for the 5%PVP composition. The swelling properties of PVP/sago and PVA/sago hydrogel decreased with increasing amount of sago but the crosslink density of the hydrogels also reduced. (author)

  13. Bioinspired Smart Actuator Based on Graphene Oxide-Polymer Hybrid Hydrogels.

    Science.gov (United States)

    Wang, Tao; Huang, Jiahe; Yang, Yiqing; Zhang, Enzhong; Sun, Weixiang; Tong, Zhen

    2015-10-28

    Rapid response and strong mechanical properties are desired for smart materials used in soft actuators. A bioinspired hybrid hydrogel actuator was designed and prepared by series combination of three trunks of tough polymer-clay hydrogels to accomplish the comprehensive actuation of "extension-grasp-retraction" like a fishing rod. The hydrogels with thermo-creep and thermo-shrinking features were successively irradiated by near-infrared (NIR) to execute extension and retraction, respectively. The GO in the hydrogels absorbed the NIR energy and transformed it into thermo-energy rapidly and effectively. The hydrogel with adhesion or magnetic force was adopted as the "hook" of the hybrid hydrogel actuator for grasping object. The hook of the hybrid hydrogel actuator was replaceable according to applications, even with functional materials other than hydrogels. This study provides an innovative concept to explore new soft actuators through combining response hydrogels and programming the same stimulus.

  14. Radiation crosslinking of starch/water-soluble polymer blends for hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z. [Radiation Processing Technology Division, Malaysian Institute Nuclear Technology Research Malaysia (MINT), Bangi, 43000 Kajang (Malaysia)

    2000-03-01

    Water-soluble polymers such as PVP(polyvinyl pyrrolidone) and PVA(polyvinyl alcohol), in aqueous solution can form hydrogel easily upon gamma or electron beam irradiation. The properties of hydrogels, particularly for wound dressing application, can be further improved by adding sago starch to the blend. Results show improved gel strength and elongation properties of the hydrogel with increasing sago concentration. It was found that the PVA/sago hydrogel gives better gel strength and elongation than the PVP/sago hydrogel. The tackiness property of the PVA/sago hydrogel increased with increase amount of sago starch added. In case of PVP/sago hydrogel, the tackiness property shows significant increase with increasing amount of sago except for the 5%PVP composition. The swelling properties of PVP/sago and PVA/sago hydrogel decreased with increasing amount of sago but the crosslink density of the hydrogels also reduced. (author)

  15. Adhesion of Pseudomonas aeruginosa and Staphylococcus epidermidis to silicone-hydrogel contact lenses.

    Science.gov (United States)

    Henriques, Mariana; Sousa, Cláudia; Lira, Madalena; Elisabete, M; Oliveira, Real; Oliveira, Rosário; Azeredo, Joana

    2005-06-01

    The purpose of this study is to compare the adhesion capabilities of the most important etiologic agents of microbial ocular infection to the recently available silicone-hydrogel lenses with those to a conventional hydrogel lens. In vitro static adhesion assays of Pseudomonas aeruginosa 10,145, Staphylococcus epidermidis 9142 (biofilm-positive), and 12,228 (biofilm-negative) to two extended-wear silicone-hydrogel lenses (balafilcon A and lotrafilcon A), a daily wear silicone-hydrogel lens (galyfilcon A) and a conventional hydrogel (etafilcon A) were performed. To interpret the adhesion results, lens surface relative hydrophobicity was assessed by water contact angle measurements. P. aeruginosa and S. epidermidis 9142 exhibited greater adhesion capabilities to the extended wear silicone-hydrogel lenses than to the daily wear silicone- and conventional hydrogel lenses (p adhesion extent of these strains to galyfilcon A and etafilcon A. The biofilm negative strain of S. epidermidis adhered in larger extents to the silicone-hydrogel lenses than to the conventional hydrogel (p contact angle measurements revealed that the extended wear silicone-hydrogel lenses are hydrophobic, whereas the daily wear silicone- and conventional hydrogel lenses are hydrophilic. As a result of their hydrophobicity, the extended wear silicone-hydrogel lenses (lotrafilcon A and balafilcon A) may carry higher risk of microbial contamination than both the hydrophilic daily wear silicone-hydrogel lens, galyfilcon A and the conventional hydrogel lens, etafilcon A.

  16. Studies on the properties of poly (ethylene oxide) R-150 hydrogel films formed by irradiation graft

    International Nuclear Information System (INIS)

    Yang Zhanshan; Zhu Nankang; Yang Shuqin; Qiang Yizhong

    1999-01-01

    In order to improve the mechanical properties of poly (ethylene oxide) (PEO) hydrogel film was used as wound dressing. The chemical and physical properties of the PEO R-150 graft hydrogel film formed by blends of electron beam irradiated-PEO R-150 and poly(vinyl alcohol) (PVA) were studied. The experimental results showed that the crosslinking densities of the PEO R-150 graft hydrogel increased along with the increasing of the irradiation doses and decreased with the increasing of the blend concentrations. While the PVA graft proportions did not produce obvious effects on the crosslinking density of the graft hydrogel. The crosslinking density of the graft hydrogel were obviously lower than that of the pure PVA hydrogel. The equilibrium water content of the graft hydrogel decrease as the irradiation dose and the PVA graft proportion increased; but they increased as the blend concentration increased. The equilibrium water content of the graft hydrogel was obviously higher than those of the pure PVA hydrogel. The hardness of the PVA hydrogel film increased with the irradiation dose. The hardness of the graft hydrogel decreased with the blend concentration, whereas it increased with the PVA graft proportion. The results suggest the PVA produces a main effect on the crosslinking density of the graft hydrogel, the PEO R-150 produces a main effect on the equilibrium water content of the graft hydrogel, and the both polymers have double effects on the hardness of the graft hydrogel

  17. 3D Cell Culture in Alginate Hydrogels

    Directory of Open Access Journals (Sweden)

    Therese Andersen

    2015-03-01

    Full Text Available This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent, and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.

  18. Biopolymer-based hydrogels as injectable materials for tissue repair scaffolds

    International Nuclear Information System (INIS)

    Fiejdasz, Sylwia; Szczubiałka, Krzysztof; Lewandowska-Łańcucka, Joanna; Nowakowska, Maria; Osyczka, Anna M

    2013-01-01

    The progress in tissue regeneration is strongly dependent on the development of biocompatible materials with properties resembling those of a native tissue. Also, the application of noninvasive methods of delivering the scaffold into the tissue defect is of great importance. In this study we present a group of biopolymer-based materials as potential injectable scaffolds. In contrast to other studies involving collagen neutralization or additional incubation of gel in genipin solution, we propose collagen and collagen–chitosan gels crosslinked in situ with genipin. Since some parameters of the cells should be considered in the microscale, the steady-state fluorescence anisotropy was applied to study the microenvironment of the gels. To our knowledge we are the first to report on microrheological properties, such as gel time and microviscosity, for this group of hydrogels. Rapid gelation at physiological temperatures found makes these materials of special interest in applications requiring gel injectability. Physico-chemical investigation showed the influence of the crosslinking agent concentration and chitosan addition on the crosslinking degree, swelling ratio, gel microviscosity, and the degradation rate. Strong correlation was revealed between the surface wettability and the viability of cultured mesenchymal stem cells. Cytotoxicity studies indicated that the collagen–chitosan hydrogels showed the best biocompatibility. (paper)

  19. Hydrogel doped with nanoparticles for local sustained release of siRNA in breast cancer.

    Science.gov (United States)

    Segovia, Nathaly; Pont, Maria; Oliva, Nuria; Ramos, Victor; Borrós, Salvador; Artzi, Natalie

    2015-01-28

    Of all the much hyped and pricy cancer drugs, the benefits from the promising siRNA small molecule drugs are limited. Lack of efficient delivery vehicles that would release the drug locally, protect it from degradation, and ensure high transfection efficiency, precludes it from fulfilling its full potential. This work presents a novel platform for local and sustained delivery of siRNA with high transfection efficiencies both in vitro and in vivo in a breast cancer mice model. siRNA protection and high transfection efficiency are enabled by their encapsulation in oligopeptide-terminated poly(β-aminoester) (pBAE) nanoparticles. Sustained delivery of the siRNA is achieved by the enhanced stability of the nanoparticles when embedded in a hydrogel scaffold based on polyamidoamine (PAMAM) dendrimer cross-linked with dextran aldehyde. The combination of oligopeptide-terminated pBAE polymers and biodegradable hydrogels shows improved transfection efficiency in vivo even when compared with the most potent commercially available transfection reagents. These results highlight the advantage of using composite materials for successful delivery of these highly promising small molecules to combat cancer. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. FNCA guideline on development of hydrogel and oligosaccharides by radiation processing

    International Nuclear Information System (INIS)

    Kudo, Hisaaki; Yoshii, Fumio; Kume, Tamikazu

    2009-10-01

    This report summarizes the current status of development of hydrogel and oligosaccharides by radiation (electron beams and gamma rays) processing in Asian countries, as an outcome of activities of the FNCA (Forum for Nuclear Co-operation in Asia)-industry group during the phase 2 (2006-2008), as one of FNCA Guidelines. The nine countries, Bangladesh (since 2007), China, Indonesia, Japan, Korea, Malaysia, Philippines, Thailand and Vietnam, participates in the phase 2 of the FNCA-industry group, focusing on radiation processing of natural polymers. Participating countries have been studying radiation processing of natural polymers such as chitosan from shrimp/crab shells and carrageenan taken from seaweeds, in terms of cross-linking for gel and degradation for oligosaccharides. The former obtains hydrogel which can absorb a lot of water, and application for wound dressing and super water absorbent in the fields of medical and environmental conservation are expected. The latter obtained oligosaccharides have functions as growth promoter and elicitor activator of plants, sea-creatures and livestocks etc., and application in the fields of agri- and aqua- cultures are expected. This Guideline consists of 3 parts; part 1 describes the outline of radiation chemistry of polymers; part 2 compiles the protocols of versatile applications; part 3 refers the examples of cost analysis and current status of the technology. This Guideline would facilitate development, commercialization and technical transfer to end-users of radiation processing of natural polymers. (author)

  1. Novel cryomilled physically cross-linked biodegradable hydrogel microparticles as carriers for inhalation therapy.

    Science.gov (United States)

    El-Sherbiny, I M; Smyth, H D C

    2010-01-01

    In this study, novel biodegradable physically cross-linked hydrogel microparticles were developed and evaluated in-vitro as potential carriers for inhalation therapy. These hydrogel microparticles were prepared to be respirable (desired aerodynamic size) when dry and also designed to avoid the macrophage uptake (attain large swollen size once deposited in lung). The swellable microparticles, prepared using cryomilling, were based on Pluronic® F-108 in combination with PEG grafted onto both chitosan (Cs) and its N-phthaloyl derivative (NPHCs). Polymers synthesized in the study were characterized using EA, FTIR, 2D-XRD and DSC. Morphology, particle size, density, biodegradation and moisture content of the microparticles were quantified. Swelling characteristics for both drug-free and drug-loaded microparticles showed excellent size increases (between 700-1300%) and the release profiles indicated sustained release could be achieved for up to 20 days. The respirable microparticles showed drug loading efficiency up to 92%. The enzymatic degradation of developed microparticles started within the first hour and only ∼10% weights were remaining after 10 days. In conclusion, these respirable microparticles demonstrated promising in-vitro performance for potential sustained release vectors in pulmonary drug delivery.

  2. Accelerated in vitro release testing of implantable PLGA microsphere/PVA hydrogel composite coatings.

    Science.gov (United States)

    Shen, Jie; Burgess, Diane J

    2012-01-17

    Dexamethasone loaded poly(lactic-co-glycolic acid) (PLGA) microsphere/PVA hydrogel composites have been investigated as an outer drug-eluting coating for implantable devices such as glucose sensors to counter negative tissue responses to implants. The objective of this study was to develop a discriminatory, accelerated in vitro release testing method for this drug-eluting coating using United States Pharmacopeia (USP) apparatus 4. Polymer degradation and drug release kinetics were investigated under "real-time" and accelerated conditions (i.e. extreme pH, hydro-alcoholic solutions and elevated temperatures). Compared to "real-time" conditions, the initial burst and lag phases were similar using hydro-alcoholic solutions and extreme pH conditions, while the secondary apparent zero-order release phase was slightly accelerated. Elevated temperatures resulted in a significant acceleration of dexamethasone release. The accelerated release data were able to predict "real-time" release when applying the Arrhenius equation. Microsphere batches with faster and slower release profiles were investigated under "real-time" and elevated temperature (60°C) conditions to determine the discriminatory ability of the method. The results demonstrated both the feasibility and the discriminatory ability of this USP apparatus 4 method for in vitro release testing of drug loaded PLGA microsphere/PVA hydrogel composites. This method may be appropriate for similar drug/device combination products and drug delivery systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Laminin-111-derived peptide conjugated fibrin hydrogel restores salivary gland function.

    Directory of Open Access Journals (Sweden)

    Kihoon Nam

    Full Text Available Hyposalivation reduces the patient quality of life, as saliva is important for maintaining oral health. Current treatments for hyposalivation are limited to medications such as the muscarinic receptor agonists, pilocarpine and cevimeline. However, these therapies only provide temporary relief. Therefore, alternative therapies are essential to restore salivary gland function. An option is to use bioengineered scaffolds to promote functional salivary gland regeneration. Previous studies demonstrated that the laminin-111 protein is critical for intact salivary gland cell cluster formation and organization. However, laminin-111 protein as a whole is not suitable for clinical applications as some protein domains may contribute to unwanted side effects such as degradation, tumorigenesis and immune responses. Conversely, the use of synthetic laminin-111 peptides makes it possible to minimize the immune reactivity or pathogen transfer. In addition, it is relatively simple and inexpensive as compared to animal-derived proteins. Therefore, the goal of this study was to demonstrate whether a 20 day treatment with laminin-111-derived peptide conjugated fibrin hydrogel promotes tissue regeneration in submandibular glands of a wound healing mouse model. In this study, laminin-111-derived peptide conjugated fibrin hydrogel significantly accelerated formation of salivary gland tissue. The regenerated gland tissues displayed not only structural but also functional restoration.

  4. Bioactive poly(ethylene glycol) hydrogels to recapitulate the HSC niche and facilitate HSC expansion in culture.

    Science.gov (United States)

    Cuchiara, Maude L; Coşkun, Süleyman; Banda, Omar A; Horter, Kelsey L; Hirschi, Karen K; West, Jennifer L

    2016-04-01

    Hematopoietic stem cells (HSCs) have been used therapeutically for decades, yet their widespread clinical use is hampered by the inability to expand HSCs successfully in vitro. In culture, HSCs rapidly differentiate and lose their ability to self-renew. We hypothesize that by mimicking aspects of the bone marrow microenvironment in vitro we can better control the expansion and differentiation of these cells. In this work, derivatives of poly(ethylene glycol) diacrylate hydrogels were used as a culture substrate for hematopoietic stem and progenitor cell (HSPC) populations. Key HSC cytokines, stem cell factor (SCF) and interferon-γ (IFNγ), as well as the cell adhesion ligands RGDS and connecting segment 1 were covalently immobilized onto the surface of the hydrogels. With the use of SCF and IFNγ, we observed significant expansion of HSPCs, ∼97 and ∼104 fold respectively, while maintaining c-kit(+) lin(-) and c-kit(+) Sca1(+) lin(-) (KSL) populations and the ability to form multilineage colonies after 14 days. HSPCs were also encapsulated within degradable poly(ethylene glycol) hydrogels for three-dimensional culture. After expansion in hydrogels, ∼60% of cells were c-kit(+), demonstrating no loss in the proportion of these cells over the 14 day culture period, and ∼50% of colonies formed were multilineage, indicating that the cells retained their differentiation potential. The ability to tailor and use this system to support HSC growth could have implications on the future use of HSCs and other blood cell types in a clinical setting. © 2015 Wiley Periodicals, Inc.

  5. Biocompatible nanomaterials based on dendrimers, hydrogels and hydrogel nanocomposites for use in biomedicine

    Science.gov (United States)

    Khoa Nguyen, Cuu; Quyen Tran, Ngoc; Phuong Nguyen, Thi; Hai Nguyen, Dai

    2017-03-01

    Over the past decades, biopolymer-based nanomaterials have been developed to overcome the limitations of other macro- and micro- synthetic materials as well as the ever increasing demand for the new materials in nanotechnology, biotechnology, biomedicine and others. Owning to their high stability, biodegradability, low toxicity, and biocompatibility, biopolymer-based nanomaterials hold great promise for various biomedical applications. The pursuit of this review is to briefly describe our recent studies regarding biocompatible biopolymer-based nanomaterials, particularly in the form of dendrimers, hydrogels, and hydrogel composites along with the synthetic and modification approaches for the utilization in drug delivery, tissue engineering, and biomedical implants. Moreover, in vitro and in vivo studies for the toxicity evaluation are also discussed.

  6. Bacterial populations on silicone hydrogel and hydrogel contact lenses after swimming in a chlorinated pool.

    Science.gov (United States)

    Choo, Jennifer; Vuu, Kathy; Bergenske, Peter; Burnham, Kara; Smythe, Jennifer; Caroline, Patrick

    2005-02-01

    A number of reports have indicated an association between swimming with contact lenses and subsequent eye infection. This study tests whether a hydrophilic contact lens worn while swimming accumulates bacteria present in the water. It was of interest to determine whether lens type (silicone hydrogel vs. hydrogel) affected the result. Fifteen healthy noncontact lens wearers swam for 30 minutes with a silicone hydrogel lens (PureVision, Bausch & Lomb, Rochester, NY) on one eye and a hydrogel lens (Acuvue 2, Vistakon Inc., Jacksonville, FL) on the other. Lenses were removed aseptically and placed in sterile vials 10 minutes after the subjects left the water. Microbial growth was enumerated for total numbers of colonies and categorized by species present. Numbers of colonies were compared between the two lens groups and with a water sample taken from the pool at the time of the experiment. Eight of the subjects returned on a different day and wore new lenses for 50 minutes in normal room conditions. Two lenses were lost while swimming. Twenty-seven of the remaining 28 lenses worn while swimming showed colonization, principally with Staphylococcus epidermidis, which was also by far the most common species identified from the water itself. Small numbers of Staphylococcus aureus and Streptococcus salivarius were also present in the water and on the lenses. Numbers of colonies varied among subjects (range, 0 to 230), but no differences were observed between the two lens groups. Lenses removed after 30 minutes of wear without swimming were mostly sterile, with 3 of 16 lenses showing just two colonies each. It appears that wearing a hydrophilic lens while swimming allows accumulation of microbial organisms on or in the lens, regardless of lens material. Swimmers should be advised to wear tight-fitting goggles if lenses are worn while swimming, and thorough disinfection of the lenses before overnight wear seems prudent.

  7. Injectable shear-thinning nanoengineered hydrogels for stem cell delivery

    DEFF Research Database (Denmark)

    Thakur, Ashish; Jaiswal, Manish K.; Peak, Charles W.

    2016-01-01

    -thinning characteristics, and enhanced mechanical stiffness, elastomeric properties, and physiological stability. The shear-thinning characteristics of nanocomposite hydrogels are investigated for human mesenchymal stem cell (hMSC) delivery. The hMSCs showed high cell viability after injection and encapsulated cells......Injectable hydrogels are investigated for cell encapsulation and delivery as they can shield cells from high shear forces. One of the approaches to obtain injectable hydrogels is to reinforce polymeric networks with high aspect ratio nanoparticles such as two-dimensional (2D) nanomaterials. 2D...... showed a circular morphology. The proposed shear-thinning nanoengineered hydrogels can be used for cell delivery for cartilage tissue regeneration and 3D bioprinting....

  8. Determination of the diffusion coefficient of hydrogen ion in hydrogels.

    Science.gov (United States)

    Schuszter, Gábor; Gehér-Herczegh, Tünde; Szűcs, Árpád; Tóth, Ágota; Horváth, Dezső

    2017-05-17

    The role of diffusion in chemical pattern formation has been widely studied due to the great diversity of patterns emerging in reaction-diffusion systems, particularly in H + -autocatalytic reactions where hydrogels are applied to avoid convection. A custom-made conductometric cell is designed to measure the effective diffusion coefficient of a pair of strong electrolytes containing sodium ions or hydrogen ions with a common anion. This together with the individual diffusion coefficient for sodium ions, obtained from PFGSE-NMR spectroscopy, allows the determination of the diffusion coefficient of hydrogen ions in hydrogels. Numerical calculations are also performed to study the behavior of a diffusion-migration model describing ionic diffusion in our system. The method we present for one particular case may be extended for various hydrogels and diffusing ions (such as hydroxide) which are relevant e.g. for the development of pH-regulated self-healing mechanisms and hydrogels used for drug delivery.

  9. Development of an in situ polymeric hydrogel implant of ...

    African Journals Online (AJOL)

    All rights reserved. ... inflammatory activity (paw edema test) and in vivo motor function activity in a rat ... Conclusions: The in situ hydrogels of methylprednisolone developed may be .... in the left hind paw in all rats. .... Continuous brain-derived.

  10. Evaluation of Hydrogels Based on Poloxamer 407 and Polyacrylic ...

    African Journals Online (AJOL)

    HP

    Keywords: Hydrogels, Gentamicin, Polyacrylic acid, Viscosity, Bioactivity, Poloxamer 407. Tropical Journal of Pharmaceutical Research is indexed by Science Citation Index (SciSearch), ... among others, have been made to determine its.

  11. Enhanced hydrolysis of cellulose hydrogels by morphological modification.

    Science.gov (United States)

    Alfassi, Gilad; Rein, Dmitry M; Cohen, Yachin

    2017-11-01

    Cellulose is one of the most abundant bio-renewable materials on earth, yet the potential of cellulosic bio-fuels is not fully exploited, primarily due to the high costs of conversion. Hydrogel particles of regenerated cellulose constitute a useful substrate for enzymatic hydrolysis, due to their porous and amorphous structure. This article describes the influence of several structural aspects of the cellulose hydrogel on its hydrolysis. The hydrogel density was shown to be directly proportional to the cellulose concentration in the initial solution, thus affecting its hydrolysis rate. Using high-resolution scanning electron microscopy, we show that the hydrogel particles in aqueous suspension exhibit a dense external surface layer and a more porous internal network. Elimination of the external surface layer accelerated the hydrolysis rate by up to sixfold and rendered the process nearly independent of cellulose concentration. These findings may be of practical relevance to saccharification processing costs, by reducing required solvent quantities and enzyme load.

  12. Topographical heterogeneity in transparent PVA hydrogels studied by AFM

    Energy Technology Data Exchange (ETDEWEB)

    Pramanick, Ashit Kumar; Gupta, Siddhi, E-mail: siddhigupta@nmlindia.org; Mishra, Trilochan; Sinha, Arvind

    2012-02-01

    Physically crosslinked poly (vinyl alcohol) (PVA) hydrogels have a wide range of biomedical applications. Transparent and stable PVA hydrogels synthesized by freeze-thawing method are potential candidates to be used as tissue engineering scaffolds provided they exhibit suitable topographical roughness and surface energy. The effect of processing parameters i.e., polymer concentration and number of freeze-thaw cycles on the resulting topography of the freeze-thawed transparent hydrogels has been studied and quantified using non-contact mode of an atomic force microscope (AFM) and image analysis. Simultaneously captured phase contrast images have revealed significant information about morphological changes in the topographical features and crystallinity of the hydrogels. Topographical roughness was found to decrease as a function of number of freeze-thaw cycles.

  13. Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

    Science.gov (United States)

    Khoylou, F.; Naimian, F.

    2009-03-01

    A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material.

  14. Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Khoylou, F. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of)], E-mail: fkhoylou@aeoi.org.ir; Naimian, F. [Nuclear Science and Technology Research Institute, Radiation Applications Research School, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of)

    2009-03-15

    A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material.

  15. Radiation synthesis of superabsorbent polyethylene oxide/tragacanth hydrogel

    International Nuclear Information System (INIS)

    Khoylou, F.; Naimian, F.

    2009-01-01

    A new superabsorbent hydrogel has been prepared from tragacanth and polyethylene oxide (PEO) by gamma radiation at room temperature. Tragacanth solutions with different concentrations (1%, 3% and 5%) have been blended with 5% aqueous solution of PEO at a ratio of 1:1 and irradiated at doses 5-20 kGy. The properties of the prepared composite hydrogels were evaluated in terms of the gel fraction and the swelling behavior. An unexpected growth of the gel fraction was observed in PEO/tragacanth hydrogels irradiated at 5 kGy. Incorporation of 5% tragacanth into the aqueous PEO increased significantly the swelling percent of the hydrogels to more than 14,000% and thus makes it a superabsorbent material

  16. Water absorbency of chitosan grafted acrylic acid hydrogels

    Science.gov (United States)

    Astrini, N.; Anah, L.; Haryono, A.

    2017-07-01

    Acrylic acid (AA) monomer was directly grafted onto chitosan (CTS) using potassium persulfate (KPS) as an initiator and methylenebisacrylamide (MBA) as a crosslinking agent under an inert atmosphere. One factor affecting the swelling capacity of the obtained hydrogel, KPS concentration, were studied. The hydrogel products were characterized using Fourier Transform Infrared spectroscopy (FTIR) for chemical structure and scanning electron microscopy (SEM) for morphology. Swelling of the hydrogel samples in distilled water and saline solution ( 9% NaCl ) was examined. Swelling capacity of the CTS-g-PAA hydrogels in distilled water (88.53 g/g) was higher than in NaCl solution (29.94 g/g) The highest swelling capacity value was obtained when the grafted reaction was carried out using 2.5wt% initiator

  17. Multiplexed Dosing Assays by Digitally Definable Hydrogel Volumes

    DEFF Research Database (Denmark)

    Faralli, Adele; Melander, Fredrik; Larsen, Esben Kjær Unmack

    2016-01-01

    Stable and low-cost multiplexed drug sensitivity assays using small volumes of cells or tissue are in demand for personalized medicine, including patientspecific combination chemotherapy. Spatially defined projected light photopolymerization of hydrogels with embedded active compounds is introduc...

  18. Hyaluronic acid based hydrogel system for soft tissue regeneration and drug delivery

    Science.gov (United States)

    Jha, Amit Kumar

    We have developed hyaluronic acid (HA)-based, biomimetic hydrogel matrices that are hierarchically structured, mechanically robust and biologically active. Specifically, HA-based hydrogel particles (HGPs) with controlled sizes, defined porosity, and improved stability were synthesized using different inverse emulsion systems and crosslinking chemistries. The resultant particles either contained residual functional groups or were rendered reactive by subsequent chemical modifications. HA-based doubly crosslinked networks (DXNs) were synthesized via covalent crosslinking of HA HGPs with soluble HA macromers carrying mutually reactive functional groups. These hybrid matrices are hierarchical in nature, consisting of densely crosslinked HGPs integrated in a loosely connected secondary matrix. Their mechanical properties and degradation kinetics can be readily tuned by varying the particle size, functional group density, intra- and interparticle crosslinking. To improve the biological functions of HA HGPs, perlecan domain I (PlnDI), a basement membrane proteoglycan that has strong affinity for various heparin binding growth factors (HBGFs), was successfully conjugated to the particles through the core protein via a flexible poly(ethylene glycol) (PEG) linker. The immobilized PlnDI maintains its ability to bind bone morphogenetic proteins (BMP-2) and modulates its in vitro release. A similar, sustained release of BMP-2 was achieved by encapsulating BMP-2-loaded HGPs within a photocrosslinked HA matrix. When encapsulated in HA DXNs, primary bovine chondrocytes were able to maintain their phenotype, proliferate readily and produce abundant glycosaminoglycan. Finally, cell-adhesive HA DXNs were fabricated by encapsulating gelatin-decorated HA HGPs in a secondary HA matrix. Human MSCs were shown to adhere to the composite matrix through the focal adhesion sites clustered on particle surface. The cell-adhesive composite matrices supported hMSC proliferation and migration into

  19. Radiation synthesis of biocompatible hydrogels of dextran methacrylate

    International Nuclear Information System (INIS)

    Szafulera, Kamila; Wach, Radosław A.; Olejnik, Alicja K.; Rosiak, Janusz M.; Ulański, Piotr

    2018-01-01

    The aim of this work was to synthesize biocompatible dextran-based hydrogels through crosslinking initiated by ionizing radiation. A series of derivatives of dextran has been synthesized by coupling of methacrylated glycidyl to the structure of this polysaccharide, yielding dextran methacrylate (Dex-MA) of the degree of methacrylate substitution (DS) up to 1.13 as characterised by FTIR and NMR spectroscopy. Chemically crosslinked hydrogels were formed by electron-beam irradiation of Dex-MA in aqueous solution in the absence of low-molecular-weight additives such as catalysts, monomers or crosslinking agents. Crosslinking of Dex-MA in aqueous solutions of 20 g/l and above was an efficient process, the gels were formed at doses as low as 0.5 kGy (experiments conducted up to 100 kGy) and were characterised by high content of insoluble fraction (70–100%). Due to high crosslinking density the equilibrium degree of swelling of fabricated gels was controlled principally by the initial concentration of Dex-MA solution subjected to irradiation, and it was in the range of 20 to over 100 g of water absorbed by gram of gel. Cytocompatibility of hydrogels was examined using XTT assay through evaluation of the cell viability being in indirect contact with hydrogels. The results indicated that hydrogels of Dex-MA of the average DS below 1 were not cytotoxic. Altogether, our data demonstrate that irradiation of methacrylated dextran in aqueous solution is an efficient method of fabrication of biocompatible hydrogels, which applications in regeneration medicine are anticipated. - Highlights: • Synthesis of dextran methacrylate with various degrees of substitutions. • Synthesis of dextran-based hydrogels through radiation technique. • Gel faction (GF) and equilibrium degree of swelling (EDS) study. • Cytocompatibility of Dex-MA hydrogels demonstrated (XTT test).

  20. Radiation synthesis and characterization of thermo-sensitive PNIPA/clay hydrogels

    International Nuclear Information System (INIS)

    Song Hongyan; He Suqin; Liu Wentao; Zhu Chengshen; Yang Mingcheng

    2007-01-01

    In this work, the thermo-sensitive hydrogels of PNIPA/Clay were synthesized by 60 Co-γ rays irradiation. The effects of organically modified clay and Na + clay, clay content, and dispersing condition on swelling behavior of PNIPA/clay hydrogels were investigated. The results showed that the equilibrium swelling ratio (SR) of the PNIPA/clay hydrogels is better than PNIPA, and the SR of PNIPA/organically modified clay hydrogels is the highest. With clay content increases, the SR of hydrogels became better. The deswelling behavior of hydrogel was improved, the deswelling ratio of the hydrogel with organically modified clay is highest, and ratio of losing water is 83%, while PNIPA is about 50%. The compressive properties of hydrogel composites were also examined. The results showed that the compressive properties of the PNIPA/clay hydrogels were improved distinctly than that of the conventional hydrogels without clay. And with increasing of clay content, the compressive properties of hydrogel composites improve rapidly. When the content of clay is 15%, the maximum compression force of the PNIPA/clay hydrogel is 5.28N, which is 14 times of PNIPA hydrogel and compression strength is 2.5 times. (authors)

  1. Silk Fibroin/Polyvinyl Pyrrolidone Interpenetrating Polymer Network Hydrogels

    Directory of Open Access Journals (Sweden)

    Dajiang Kuang

    2018-02-01

    Full Text Available Silk fibroin hydrogel is an ideal model as biomaterial matrix due to its excellent biocompatibility and used in the field of medical polymer materials. Nevertheless, native fibroin hydrogels show poor transparency and resilience. To settle these drawbacks, an interpenetrating network (IPN of hydrogels are synthesized with changing ratios of silk fibroin/N-Vinyl-2-pyrrolidonemixtures that crosslink by H2O2 and horseradish peroxidase. Interpenetrating polymer network structure can shorten the gel time and the pure fibroin solution gel time for more than a week. This is mainly due to conformation from the random coil to the β-sheet structure changes of fibroin. Moreover, the light transmittance of IPN hydrogel can be as high as more than 97% and maintain a level of 90% within a week. The hydrogel, which mainly consists of random coil, the apertures inside can be up to 200 μm. Elastic modulus increases during the process of gelation. The gel has nearly 95% resilience under the compression of 70% eventually, which is much higher than native fibroin gel. The results suggest that the present IPN hydrogels have excellent mechanical properties and excellent transparency.

  2. Study on antibacterial activity of hydrogel from irradiated silk protein

    International Nuclear Information System (INIS)

    Bunnak, J.; Chaisupakitsin, M.

    2001-01-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N 2 atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  3. A large deformation viscoelastic model for double-network hydrogels

    Science.gov (United States)

    Mao, Yunwei; Lin, Shaoting; Zhao, Xuanhe; Anand, Lallit

    2017-03-01

    We present a large deformation viscoelasticity model for recently synthesized double network hydrogels which consist of a covalently-crosslinked polyacrylamide network with long chains, and an ionically-crosslinked alginate network with short chains. Such double-network gels are highly stretchable and at the same time tough, because when stretched the crosslinks in the ionically-crosslinked alginate network rupture which results in distributed internal microdamage which dissipates a substantial amount of energy, while the configurational entropy of the covalently-crosslinked polyacrylamide network allows the gel to return to its original configuration after deformation. In addition to the large hysteresis during loading and unloading, these double network hydrogels also exhibit a substantial rate-sensitive response during loading, but exhibit almost no rate-sensitivity during unloading. These features of large hysteresis and asymmetric rate-sensitivity are quite different from the response of conventional hydrogels. We limit our attention to modeling the complex viscoelastic response of such hydrogels under isothermal conditions. Our model is restricted in the sense that we have limited our attention to conditions under which one might neglect any diffusion of the water in the hydrogel - as might occur when the gel has a uniform initial value of the concentration of water, and the mobility of the water molecules in the gel is low relative to the time scale of the mechanical deformation. We also do not attempt to model the final fracture of such double-network hydrogels.

  4. Recent advances in clay mineral-containing nanocomposite hydrogels.

    Science.gov (United States)

    Zhao, Li Zhi; Zhou, Chun Hui; Wang, Jing; Tong, Dong Shen; Yu, Wei Hua; Wang, Hao

    2015-12-28

    Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.

  5. Protein diffusion in photopolymerized poly(ethylene glycol) hydrogel networks

    International Nuclear Information System (INIS)

    Engberg, Kristin; Frank, Curtis W

    2011-01-01

    In this study, protein diffusion through swollen hydrogel networks prepared from end-linked poly(ethylene glycol)-diacrylate (PEG-DA) was investigated. Hydrogels were prepared via photopolymerization from PEG-DA macromonomer solutions of two molecular weights, 4600 Da and 8000 Da, with three initial solid contents: 20, 33 and 50 wt/wt% PEG. Diffusion coefficients for myoglobin traveling across the hydrogel membrane were determined for all PEG network compositions. The diffusion coefficient depended on PEG molecular weight and initial solid content, with the slowest diffusion occurring through lower molecular weight, high-solid-content networks (D gel = 0.16 ± 0.02 x 10 -8 cm 2 s -1 ) and the fastest diffusion occurring through higher molecular weight, low-solid-content networks (D gel = 11.05 ± 0.43 x 10 -8 cm 2 s -1 ). Myoglobin diffusion coefficients increased linearly with the increase of water content within the hydrogels. The permeability of three larger model proteins (horseradish peroxidase, bovine serum albumin and immunoglobulin G) through PEG(8000) hydrogel membranes was also examined, with the observation that globular molecules as large as 10.7 nm in hydrodynamic diameter can diffuse through the PEG network. Protein diffusion coefficients within the PEG hydrogels ranged from one to two orders of magnitude lower than the diffusion coefficients in free water. Network defects were determined to be a significant contributing factor to the observed protein diffusion.

  6. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    International Nuclear Information System (INIS)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-01-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  7. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    Science.gov (United States)

    Raafat, Amany I.; Eid, Mona; El-Arnaouty, Magda B.

    2012-07-01

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  8. Radiation synthesis of superabsorbent CMC based hydrogels for agriculture applications

    Energy Technology Data Exchange (ETDEWEB)

    Raafat, Amany I., E-mail: ismaelraafat_a@hotmail.com [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt); Eid, Mona; El-Arnaouty, Magda B. [Polymer Chemistry Department, National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)

    2012-07-15

    A series of superabsorbent hydrogel based on carboxymethylcellulose (CMC) and polyvinylpyrrolidone (PVP) crosslinked with gamma irradiation have been proposed for agriculture application. The effect of preparation conditions such as feed solution composition and absorbed irradiation dose on the gelation and swelling degree was evaluated. The structure and the morphology of the superabsorbent CMC/PVP hydrogel were characterized using Fourier transform infrared spectroscopy technique (FTIR), and scanning electron microscope (SEM). Effect of ionic strength and cationic and anionic kinds on the swelling behavior of the obtained hydrogel was investigated. Urea as an agrochemical model was loaded onto the obtained hydrogel to provide nitrogen (N) nutrients. The water retention capability and the urea release behavior of the CMC/PVP hydrogels were investigated. It was found that, the obtained CMC/PVP hydrogels have good swelling degree that greatly affected by its composition and absorbed dose. The swelling was also extremely sensitive to the ionic strength and cationic kind. Owing to its considerable slow urea release, good water retention capacity, being economical, and environment-friendly, it might be useful for its application in agriculture field.

  9. Research on the printability of hydrogels in 3D bioprinting

    Science.gov (United States)

    He, Yong; Yang, Feifei; Zhao, Haiming; Gao, Qing; Xia, Bing; Fu, Jianzhong

    2016-07-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films (two dimensional, 2D structures) and printing 3D structures with a special attention to the accurate printing. After a series of experiments, we discovered the relationships between the important factors such as air pressure, feedrate, or even printing distance and the printing quality of the expected structures. Dumbbell shape was observed in the lattice structures printing due to the hydrogel diffuses at the intersection. Collapses and fusion of adjacent layer would result in the error accumulation at Z direction which was an important fact that could cause printing failure. Finally, we successfully demonstrated a 3D printing hydrogel scaffold through harmonize with all the parameters. The cell viability after printing was compared with the casting and the results showed that our bioprinting method almost had no extra damage to the cells.

  10. A Novel Domperidone Hydrogel: Preparation, Characterization, Pharmacokinetic, and Pharmacodynamic Properties

    Directory of Open Access Journals (Sweden)

    Chun-Hui Zhang

    2011-01-01

    Full Text Available The purpose of the present study was to prepare a novel domperidone hydrogel. The domperidone dispersion was prepared by the solvent evaporation method. The characteristics of domperidone dispersion were measured by dynamic light scattering (DLS, scanning electronic microscopy (SEM, differential scanning calorimetry (DSC, X-ray diffractometry, and solubility test, respectively. Domperidone hydrogel was prepared by directly incorporating the domperidone dispersion in Carbopol hydrogel to increase its mucoadhesive properties to gastrointestinal tract (GIT. The in vivo pharmacokinetic and pharmacodynamic studies were investigated to evaluate the relative oral bioavailability and the propulsion efficacy of domperidone hydrogel as compared with market domperidone tablet (Motilium tablet. The particle size of domperidone dispersion in distilled water was 454.0 nm. The results of DSC and X-ray indicated that domperidone in dispersion was in amorphous state. The solubility of domperidone in the dispersion in distilled water, pH of 1, 5, and 7 buffer solution was 45.7-, 63.9-, 13.1-, and 3.7-fold higher than that of raw domperidone, respectively. The area under the plasma concentration curve (AUC0–24 in domperidone hydrogel was 2.2-fold higher than that of tablet. The prolonged propulsion efficacy in the domperidone hydrogel group compared to that in tablet group was observed in the pharmacodynamic test.

  11. Improved Concrete Materials with Hydrogel-Based Internal Curing Agents

    Directory of Open Access Journals (Sweden)

    Matthew J. Krafcik

    2017-11-01

    Full Text Available This research article will describe the design and use of polyelectrolyte hydrogel particles as internal curing agents in concrete and present new results on relevant hydrogel-ion interactions. When incorporated into concrete, hydrogel particles release their stored water to fuel the curing reaction, resulting in reduced volumetric shrinkage and cracking and thus increasing concrete service life. The hydrogel’s swelling performance and mechanical properties are strongly sensitive to multivalent cations that are naturally present in concrete mixtures, including calcium and aluminum. Model poly(acrylic acid(AA-acrylamide(AM-based hydrogel particles with different chemical compositions (AA:AM monomer ratio were synthesized and immersed in sodium, calcium, and aluminum salt solutions. The presence of multivalent cations resulted in decreased swelling capacity and altered swelling kinetics to the point where some hydrogel compositions displayed rapid deswelling behavior and the formation of a mechanically stiff shell. Interestingly, when incorporated into mortar, hydrogel particles reduced mixture shrinkage while encouraging the formation of specific inorganic phases (calcium hydroxide and calcium silicate hydrate within the void space previously occupied by the swollen particle.

  12. Reusable self-healing hydrogels realized via in situ polymerization.

    Science.gov (United States)

    Vivek, Balachandran; Prasad, Edamana

    2015-04-09

    In this work, a self-healing hydrogel has been prepared using in situ polymerization of acrylic acid and acrylamide in the presence of glycogen. The hydrogel was characterized using NMR, SEM, FT-IR, rheology, and dynamic light scattering (DLS) studies. The developed hydrogel exhibits self-healing properties at neutral pH, high swelling ability, high elasticity, and excellent mechanical strength. The hydrogel exhibits modulus values (G', G″) as high as 10(6) Pa and shows an exceptionally high degree of swelling ratio (∼3.5 × 10(3)). Further, the polymer based hydrogel adsorbs toxic metal ions (Cd(2+), Pb(2+), and Hg(2+)) and organic dyes (methylene blue and methyl orange) from contaminated water with remarkable efficiency (90-98%). The mechanistic analysis indicated the presence of pseudo-second-order reaction kinetics. The reusability of the hydrogel has been demonstrated by repeating the adsorption-desorption process over five cycles with identical results in the adsorption efficiency.

  13. Engineering Protein Hydrogels Using SpyCatcher-SpyTag Chemistry.

    Science.gov (United States)

    Gao, Xiaoye; Fang, Jie; Xue, Bin; Fu, Linglan; Li, Hongbin

    2016-09-12

    Constructing hydrogels from engineered proteins has attracted significant attention within the material sciences, owing to their myriad potential applications in biomedical engineering. Developing efficient methods to cross-link tailored protein building blocks into hydrogels with desirable mechanical, physical, and functional properties is of paramount importance. By making use of the recently developed SpyCatcher-SpyTag chemistry, we successfully engineered protein hydrogels on the basis of engineered tandem modular elastomeric proteins. Our resultant protein hydrogels are soft but stable, and show excellent biocompatibility. As the first step, we tested the use of these hydrogels as a drug carrier, as well as in encapsulating human lung fibroblast cells. Our results demonstrate the robustness of the SpyCatcher-SpyTag chemistry, even when the SpyTag (or SpyCatcher) is flanked by folded globular domains. These results demonstrate that SpyCatcher-SpyTag chemistry can be used to engineer protein hydrogels from tandem modular elastomeric proteins that can find applications in tissue engineering, in fundamental mechano-biological studies, and as a controlled drug release vehicle.

  14. Formation of carboxymethyl cellulose hydrogel containing silver nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Seok; Kuang, Jia; Gwon, Hui Jeong; Lim, Youn Mook; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-12-15

    Silver nanoparticles (AgNPs) can be used in the areas such as integrate circuit, cell electrode and antimicrobial deodorant. In this study, AgNPs have been prepared by using AgNO{sub 3} aqueous solution in the carboxymethyl cellulose (CMC) hydrogel. CMC powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make CMC hydrogel. CMC hydrogels were dipped into 1.0 x 10{sup -2} M AgNO{sub 3} solution for 1 hour. After that, the swollen hydrogels were irradiated by gamma-ray for the formation of AgNPs. The characteristics of silver nanoparticles in the CMC hydrogels were monitored by UV-Vis and the morphological study and dispersed coefficient of particles were investigated by FE-SEM/EDX. It was observed that the sodium salt in the CMC is crucial to the formation of silver nanoparticle. Finally, antibacterial tests indiacted that the hydrogel containing silver nanoparticle has antibacterial activity.

  15. Properties of radiation-synthesized polyvinylpyrrolidone/chitosan hydrogel blends

    Energy Technology Data Exchange (ETDEWEB)

    Mahmud, Maznah [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia); Daik, Rusli [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia 43600 Bangi, Selangor (Malaysia); Adam, Zainah [Radiation Processing Technology Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)

    2015-09-25

    Poly(vinylpyrrolidone) (PVP)-crosslinked chitosan hydrogels were prepared by gamma radiation at various doses; 1, 3 5, 7, 10, 15, 20, 25 and 30kGy. Gamma radiation was used as a crosslinking tool which requires no chemical initiator, no heating process and need no purification step on the end products obtained. The hydrogel formulations were composed of 6% chitosan with average molecular weight (Mw) = 48 800 g/mol and 14% PVP with Mw = 10 000 g/mol in 2% lactic acid. Physical properties of hydrogels such as gel fraction and swelling property at pH 5.5 and pH 7.0 as well as syneresis activity were determined. It was found that different radiation dose induces different effect on hydrogels’ network formed. Morphological study of hydrogels has been carried out by scanning electron microscope (SEM). From these preliminary evaluations, it can be concluded that gamma radiation is an effective tool for network development of hydrogels and it also induces enhancement on characteristics of hydrogels synthesized.

  16. Study on antibacterial activity of hydrogel from irradiated silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Bunnak, J; Chaisupakitsin, M [King Mongkut' s Institute of Technology Lardkrabang, Bangkok (Thailand)

    2001-03-01

    Hydrogels for biomedical application were prepared from solution blends of 3% silk protein and 3%, 10% poly (vinyl alcohol) (PVA) and followed with irradiation. Mixture of hydrogels were gamma irradiated at 10, 20, 30, 40 and 50 kGy under N{sub 2} atmosphere. To clarify anti-bacterial activity of hydrogels, modified of the Agar disk diffusion method and American Association of Textile Chemists and Colorists, AATCC Test Method 90-1977, were carried out. The four kinds of bacteria such as Escherichia coli, Bacillus subtilis, Staphylococcus aureus and Staphylococcus epidermidis, were used. It was found that a 1:3 volume ratio of 3% silk protein and 3% PVA respectively, at 50 kGy irradiation, is suitable conditions for preparation hydrogels and trend to indicate the highest of an antibacterial activity against E. coli, B. subtilis and S. aureus. However the antibacterial activity of hydrogels against S. epidermidis was not clearly. These results are very useful to expand the application of hydrogel from irradiated silk protein to the medical products. (author)

  17. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite.

    Science.gov (United States)

    Mi Kyung Kim; Hyojung Kim; Jung, Yeon Su; Adem, Kenana M A; Bawazir, Sarah S; Stefanini, Cesare; Lee, Hyunjoo J

    2017-07-01

    An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.

  18. Mechano-actuated ultrafast full-colour switching in layered photonic hydrogels.

    Science.gov (United States)

    Yue, Youfeng; Kurokawa, Takayuki; Haque, Md Anamul; Nakajima, Tasuku; Nonoyama, Takayuki; Li, Xufeng; Kajiwara, Itsuro; Gong, Jian Ping

    2014-08-18

    Photonic crystals with tunability in the visible region are of great interest for controlling light diffraction. Mechanochromic photonic materials are periodically structured soft materials designed with a photonic stop-band that can be tuned by mechanical forces to reflect specific colours. Soft photonic materials with broad colour tunability and fast colour switching are invaluable for application. Here we report a novel mechano-actuated, soft photonic hydrogel that has an ultrafast-response time, full-colour tunable range, high spatial resolution and can be actuated by a very small compressive stress. In addition, the material has excellent mechanical stability and the colour can be reversibly switched at high frequency more than 10,000 times without degradation. This material can be used in optical devices, such as full-colour display and sensors to visualize the time evolution of complicated stress/strain fields, for example, generated during the motion of biological cells.

  19. Solutions for care of silicone hydrogel lenses.

    Science.gov (United States)

    Willcox, Mark D P

    2013-01-01

    During wear of contact lenses on a daily wear basis, it is necessary to disinfect the lens overnight before reinserting the lens the next day. The ability of the solutions used for this to disinfect lenses and lens cases is important for safe lens wear. The literature on the disinfecting ability of multipurpose disinfecting solutions (MPDS) commonly used with silicone hydrogel lenses reported during the period 2000 to 2012 is reviewed, as this is the period of time during which these lenses have been commercially available. Particular emphasis is placed on the ability of disinfecting solutions to control colonization of lens cases by microbes and changes in composition and use of the solutions. In addition, the literature is reviewed on ways of minimizing lens case microbial contamination. Maintaining the hygiene of contact lenses and lens cases is important in minimizing various forms of corneal infiltrative events that occur during lens wear. Although lens case contamination is not associated with different lenses, it is determined by use of different MPDS. MPDS that allow more frequent or heavy contamination of cases by Gram-negative bacteria are associated with a higher incidence of corneal infiltrative events. MPDS are now available that contain dual disinfectants. Wiping lens cases with tissues or using lens cases that incorporate silver are associated with reductions in contamination in clinical trials. Similarly, using MPDS to rub and rinse lenses before disinfection may reduce levels of microbes on lenses. The MPDS also contain surfactants that help reduce deposition and denaturation of proteins on lenses. Improvements in MPDS formulations and hygiene practices may help to reduce the incidence of adverse events that are seen during use with silicone hydrogel lenses.

  20. Electromechanical response of silk fibroin hydrogel and conductive polycarbazole/silk fibroin hydrogel composites as actuator material.

    Science.gov (United States)

    Srisawasdi, Thanida; Petcharoen, Karat; Sirivat, Anuvat; Jamieson, Alexander M

    2015-11-01

    Pure silk fibroin (SF) hydrogel and polycarbazole/silk fibroin (SF/PCZ) hydrogels were fabricated by solvent casting technique to evaluate electromechanical responses, dielectric properties, and cantilever deflection properties as functions of electric field strength, SF concentration, glutaraldehyde concentration, and PCZ concentration in the blends. Electromechanical properties were characterized in oscillatory shear mode at electric field strengths ranging from 0 to 600V/mm and at a temperature of 27°C. For both the pristine SF and SF/PCZ hydrogels, the storage modulus response (ΔG') and the storage modulus sensitivity (ΔG'/G'0) increased dramatically with increasing electric field strength. The pristine hydrogel possessed the highest storage modulus sensitivity value of 5.87, a relatively high value when compared with other previously studied electroactive polymers. With the addition of conductive PCZ in SF hydrogel, the storage modulus sensitivity and the relative dielectric constant decreased; the conductive polymer thus provided the softening effect under electric field. In the deflection response, the dielectrophoresis force and deflection distance increased monotonically with electric field strength, where the pure SF hydrogel showed the highest deflection distance and dielectrophoresis force. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Hydrogel-based bioflocculants for the removal of organic pollutants from biodiesel wastewater

    CSIR Research Space (South Africa)

    Fosso-Kankeu, E

    2017-09-01

    Full Text Available hydrogels were characterized using X-Ray diffraction, Fourier transformed infra-red spectroscopy and scanning electron microscope. It was found that the synthesis provided the composite with the functional groups of the individual components. The hydrogels...

  2. Skin-inspired hydrogel-elastomer hybrids with robust interfaces and functional microstructures

    Science.gov (United States)

    Yuk, Hyunwoo; Zhang, Teng; Parada, German Alberto; Liu, Xinyue; Zhao, Xuanhe

    2016-06-01

    Inspired by mammalian skins, soft hybrids integrating the merits of elastomers and hydrogels have potential applications in diverse areas including stretchable and bio-integrated electronics, microfluidics, tissue engineering, soft robotics and biomedical devices. However, existing hydrogel-elastomer hybrids have limitations such as weak interfacial bonding, low robustness and difficulties in patterning microstructures. Here, we report a simple yet versatile method to assemble hydrogels and elastomers into hybrids with extremely robust interfaces (interfacial toughness over 1,000 Jm-2) and functional microstructures such as microfluidic channels and electrical circuits. The proposed method is generally applicable to various types of tough hydrogels and diverse commonly used elastomers including polydimethylsiloxane Sylgard 184, polyurethane, latex, VHB and Ecoflex. We further demonstrate applications enabled by the robust and microstructured hydrogel-elastomer hybrids including anti-dehydration hydrogel-elastomer hybrids, stretchable and reactive hydrogel-elastomer microfluidics, and stretchable hydrogel circuit boards patterned on elastomer.

  3. Electron beam irradiation crosslinked hydrogels based on tyramine conjugated gum tragacanth.

    Science.gov (United States)

    Tavakol, Moslem; Dehshiri, Saeedeh; Vasheghani-Farahani, Ebrahim

    2016-11-05

    In the present study, electron beam irradiation was applied to prepare a chemically crosslinked hydrogel based on tyramine conjugated gum tragacanth. Then, the gel content, swelling behavior and cytotoxicity of the hydrogels were evaluated. The gel content of the hydrogels was in the range of 75-85%. Equilibrium swelling degree of the hydrogels decreased from 51 to 14 with increasing polymer concentration and irradiation dose. Moisture retention capability of the hydrogels after 5h incubation at 37°C was in the range of 45-52 that is comparable with of commercial hydrogels. The cytotoxicity analysis showed the good biocompatibility of hydrogels. These results indicated that electron beam irradiation is a promising method to prepare chemically crosslinked tyramine conjugated gum tragacanth hydrogels for biomedical applications. Also, the versatility of electron beam irradiation for crosslinking of a variety of polymers possessing tyramine groups was demonstrated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Dextran-based hydrogel containing chitosan microparticles loaded with growth factors to be used in wound healing

    International Nuclear Information System (INIS)

    Ribeiro, M.P.; Morgado, P.I.; Miguel, S.P.; Coutinho, P.; Correia, I.J.

    2013-01-01

    Skin injuries are traumatic events, which are seldom accompanied by complete structural and functional restoration of the original tissue. Different strategies have been developed in order to make the wound healing process faster and less painful. In the present study in vitro and in vivo assays were carried out to evaluate the applicability of a dextran hydrogel loaded with chitosan microparticles containing epidermal and vascular endothelial growth factors, for the improvement of the wound healing process. The carriers' morphology was characterized by scanning electron microscopy. Their cytotoxicity profile and degradation by-products were evaluated through in vitro assays. In vivo experiments were also performed to evaluate their applicability for the treatment of skin burns. The wound healing process was monitored through macroscopic and histological analysis. The macroscopic analysis showed that the period for wound healing occurs in animals treated with microparticle loaded hydrogels containing growth factors that were considerably smaller than that of control groups. Moreover, the histological analysis revealed the absence of reactive or granulomatous inflammatory reaction in skin lesions. The results obtained both in vitro and in vivo disclosed that these systems and its degradation by-products are biocompatible, contributed to the re-establishment of skin architecture and can be used in a near future for the controlled delivery of other bioactive agents used in regenerative medicine. - Highlights: • Evaluation of a hydrogel loaded with microparticles containing growth factors for wound healing • In vitro and in vivo assays were performed to characterize the properties of the skin substitute. • The monitoring of the wound healing process was done by macroscopic and histological analysis

  5. Dextran-based hydrogel containing chitosan microparticles loaded with growth factors to be used in wound healing

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M.P. [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal); UDI-IPG, Research Unit for Inland Development, Polytechnic Institute of Guarda, Guarda (Portugal); Morgado, P.I.; Miguel, S.P. [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal); Coutinho, P. [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal); UDI-IPG, Research Unit for Inland Development, Polytechnic Institute of Guarda, Guarda (Portugal); Correia, I.J., E-mail: icorreia@ubi.pt [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal)

    2013-07-01

    Skin injuries are traumatic events, which are seldom accompanied by complete structural and functional restoration of the original tissue. Different strategies have been developed in order to make the wound healing process faster and less painful. In the present study in vitro and in vivo assays were carried out to evaluate the applicability of a dextran hydrogel loaded with chitosan microparticles containing epidermal and vascular endothelial growth factors, for the improvement of the wound healing process. The carriers' morphology was characterized by scanning electron microscopy. Their cytotoxicity profile and degradation by-products were evaluated through in vitro assays. In vivo experiments were also performed to evaluate their applicability for the treatment of skin burns. The wound healing process was monitored through macroscopic and histological analysis. The macroscopic analysis showed that the period for wound healing occurs in animals treated with microparticle loaded hydrogels containing growth factors that were considerably smaller than that of control groups. Moreover, the histological analysis revealed the absence of reactive or granulomatous inflammatory reaction in skin lesions. The results obtained both in vitro and in vivo disclosed that these systems and its degradation by-products are biocompatible, contributed to the re-establishment of skin architecture and can be used in a near future for the controlled delivery of other bioactive agents used in regenerative medicine. - Highlights: • Evaluation of a hydrogel loaded with microparticles containing growth factors for wound healing • In vitro and in vivo assays were performed to characterize the properties of the skin substitute. • The monitoring of the wound healing process was done by macroscopic and histological analysis.

  6. Addition of residues and reintroduction of microorganisms in Jatropha curcas cultivated in degraded soil

    Directory of Open Access Journals (Sweden)

    Adriana A. Santos

    2016-04-01

    Full Text Available ABSTRACT The aim of this study was to evaluate, through mycorrhization (root colonization and number of spores of arbuscular mycorrhizal fungi - AMF, leaf acid phosphatase and soil chemical characteristics, the effects of the addition of residues (macrophytes and ash, hydrogel and the reintroduction of microorganisms in a degraded area cultivated with jatropha. Degradation occurred when the surface soil was removed during the construction of a hydroelectric power plant. The experiment was set in a randomized block design, using a 2 x 2 x 4 factorial scheme, i.e., two inoculation treatments (with and without soil-inoculum, two hydrogel treatments (with and without and four with the addition of residues (macrophytes - MAC, ash, MAC + ash and control, without residues applied in the planting hole, with 4 replicates and 5 plants in each replicate. Soil from preserved Cerrado area was used as a source of microorganisms, including AMF. The conclusion is that, after 12 months of planting, the hydrogel increased root colonization, while the chemical characteristics of the degraded soil responded positively to the addition of MAC and MAC + ash, with increase in pH and SB and reduction of Al and H + Al. The addition of the soil-inoculum, along with MAC and MAC + ash, promoted higher mycorrhizal colonization and number of spores and reduced amounts of leaf acid phosphatase, indicating increased absorption of P by the host.

  7. Synthesis, characterization and application in biomedicine of a novel chondroitin sulfate based hydrogel and bioadhesive

    Science.gov (United States)

    Strehin, Iossif

    Clinically, there exists a need for adhesive biomaterials. There is room to improve upon what is currently on the market as it is either too toxic, lacks the required adhesive strength and/or lacks the desired degradation properties. The general goals of this thesis all focused on designing a biomaterial which would improve upon these shortcomings while at the same time allow for modifications to meet the needs for the specific application of interest. To accomplish this task, it was important to choose the appropriate composition and crosslinking chemistry which will allow the most flexibility. Chondroitin sulfate (CS) was chosen as the principle component of the hydrogel because it is a ubiquitous glycosaminoglycan (GAG) found in almost all tissues in the body. Many variants of CS exist with each one possessing unique biological activity allowing for tight control over these properties of the material. To modulate cell migration through the adhesive, polyethylene glycol (PEG) or blood was used as the second constituent. The former made the scaffold act as a cell barrier while the ladder could be used in varying concentrations to modulate cell adhesion and migration into the biomaterial. Also, the CS and blood components are both biodegradable and degradation can be controlled using various methods. While the constituents were chosen to allow flexibility in the biological activity and cell migration into the scaffold, the crosslinking chemistry was chosen to allow control over the mechanical properties as well as to increase tissue adhesion. By functionalizing the carboxyl groups of the GAG with N-hydroxysuccinimide (NHS), the resulting chondroitin sulfate succinimidyl succinate (CS-NHS) molecule could react with primary amines on polymers to form a hydrogel as well as the primary amines on proteins comprising tissue to anchor the hydrogel to the tissue. The material has been characterized and optimized for several applications. The applications described here

  8. In Vivo Assessment of Bone Regeneration in Alginate/Bone ECM Hydrogels with Incorporated Skeletal Stem Cells and Single Growth Factors

    Science.gov (United States)

    Gothard, David; Smith, Emma L.; Kanczler, Janos M.; Black, Cameron R.; Wells, Julia A.; Roberts, Carol A.; White, Lisa J.; Qutachi, Omar; Peto, Heather; Rashidi, Hassan; Rojo, Luis; Stevens, Molly M.; El Haj, Alicia J.; Rose, Felicity R. A. J.; Shakesheff, Kevin M.; Oreffo, Richard O. C.

    2015-01-01

    The current study has investigated the use of decellularised, demineralised bone extracellular matrix (ECM) hydrogel constructs for in vivo tissue mineralisation and bone formation. Stro-1-enriched human bone marrow stromal cells were incorporated together with select growth factors including VEGF, TGF-β3, BMP-2, PTHrP and VitD3, to augment bone formation, and mixed with alginate for structural support. Growth factors were delivered through fast (non-osteogenic factors) and slow (osteogenic factors) release PLGA microparticles. Constructs of 5 mm length were implanted in vivo for 28 days within mice. Dense tissue assessed by micro-CT correlated with histologically assessed mineralised bone formation in all constructs. Exogenous growth factor addition did not enhance bone formation further compared to alginate/bone ECM (ALG/ECM) hydrogels alone. UV irradiation reduced bone formation through degradation of intrinsic growth factors within the bone ECM component and possibly also ECM cross-linking. BMP-2 and VitD3 rescued osteogenic induction. ALG/ECM hydrogels appeared highly osteoinductive and delivery of angiogenic or chondrogenic growth factors led to altered bone formation. All constructs demonstrated extensive host tissue invasion and vascularisation aiding integration and implant longevity. The proposed hydrogel system functioned without the need for growth factor incorporation or an exogenous inducible cell source. Optimal growth factor concentrations and spatiotemporal release profiles require further assessment, as the bone ECM component may suffer batch variability between donor materials. In summary, ALG/ECM hydrogels provide a versatile biomaterial scaffold for utilisation within regenerative medicine which may be tailored, ultimately, to form the tissue of choice through incorporation of select growth factors. PMID:26675008

  9. Riboflavin-induced photo-crosslinking of collagen hydrogel and its application in meniscus tissue engineering.

    Science.gov (United States)

    Heo, Jiseung; Koh, Rachel H; Shim, Whuisu; Kim, Hwan D; Yim, Hyun-Gu; Hwang, Nathaniel S

    2016-04-01

    A meniscus tear is a common knee injury, but its regeneration remains a clinical challenge. Recently, collagen-based scaffolds have been applied in meniscus tissue engineering. Despite its prevalence, application of natural collagen scaffold in clinical setting is limited due to its extremely low stiffness and rapid degradation. The purpose of the present study was to increase the mechanical properties and delay degradation rate of a collagen-based scaffold by photo-crosslinking using riboflavin (RF) and UV exposure. RF is a biocompatible vitamin B2 that showed minimal cytotoxicity compared to conventionally utilized photo-initiator. Furthermore, collagen photo-crosslinking with RF improved mechanical properties and delayed enzyme-triggered degradation of collagen scaffolds. RF-induced photo-crosslinked collagen scaffolds encapsulated with fibrochondrocytes resulted in reduced scaffold contraction and enhanced gene expression levels for the collagen II and aggrecan. Additionally, hyaluronic acid (HA) incorporation into photo-crosslinked collagen scaffold showed an increase in its retention. Based on these results, we demonstrate that photo-crosslinked collagen-HA hydrogels can be potentially applied in the scaffold-based meniscus tissue engineering.

  10. Cell-laden hydrogel/titanium microhybrids: Site-specific cell delivery to metallic implants for improved integration.

    Science.gov (United States)

    Koenig, Geraldine; Ozcelik, Hayriye; Haesler, Lisa; Cihova, Martina; Ciftci, Sait; Dupret-Bories, Agnes; Debry, Christian; Stelzle, Martin; Lavalle, Philippe; Vrana, Nihal Engin

    2016-03-01

    Porous titanium implants are widely used in dental, orthopaedic and otorhinolaryngology fields to improve implant integration to host tissue. A possible step further to improve the integration with the host is the incorporation of autologous cells in porous titanium structures via cell-laden hydrogels. Fast gelling hydrogels have advantageous properties for in situ applications such as localisation of specific cells and growth factors at a target area without dispersion. The ability to control the cell types in different regions of an implant is important in applications where the target tissue (i) has structural heterogeneity (multiple cell types with a defined spatial configuration with respect to each other); (ii) has physical property gradients essential for its function (such as in the case of osteochondral tissue transition). Due to their near immediate gelation, such gels can also be used for site-specific modification of porous titanium structures, particularly for implants which would face different tissues at different locations. Herein, we describe a step by step design of a model system: the model cell-laden gel-containing porous titanium implants in the form of titanium microbead/hydrogel (maleimide-dextran or maleimide-PVA based) microhybrids. These systems enable the determination of the effect of titanium presence on gel properties and encapsulated cell behaviour as a miniaturized version of full-scale implants, providing a system compatible with conventional analysis methods. We used a fibroblast/vascular endothelial cell co-cultures as our model system and by utilising single microbeads we have quantified the effect of gel microenvironment (degradability, presence of RGD peptides within gel formulation) on cell behaviour and the effect of the titanium presence on cell behaviour and gel formation. Titanium presence slightly changed gel properties without hindering gel formation or affecting cell viability. Cells showed a preference to move towards

  11. The impact of calcium carbonate as pore forming agent and drug entrapment method towards drug dissolution mechanism of amoxicillin trihydrate encapsulated by chitosan-methyl cellulose semi-IPN hydrogel for floating drug delivery system

    Science.gov (United States)

    Dewantara, Fauzi; Budianto, Emil

    2018-04-01

    Chitosan-methyl cellulose semi-IPN hydrogel is used as floating drug delivery system, and calcium carbonate also added as pore forming agent. The hydrogel network arranged by not only using biopolymer chitosan and methyl cellulose, but also the crosslink agent that is glutaraldehyde. Amoxicillin trihydrate entrapped into the polymer network with two different method, in situ loading and post loading. Furthermore both method has been tested for drug entrapment efficiency along with drug dissolution test, and the result for drug entrapment efficiency is in situ loading method has highest value of 100%, compared to post loading method which has value only 71%. Moreover, at the final time of drug dissolution test shows in situ loading method has value of 96% for total accumulative of drug dissolution, meanwhile post loading method has 72%. The value of drug dissolution test from both method is used for analyzing drug dissolution mechanism of amoxicillin trihydrate from hydrogel network with four mathematical drug mechanism models as parameter. The polymer network encounter destructive degradation causes by acid solution which used as dissolution medium, and the level of degradation is observed with optical microscope. However the result shows that degradation of the polymer network doesn't affect drug dissolution mechanism directly. Although the pore forming agent causes the pore inside the hydrogel network create interconnection and it was quite influential to drug dissolution mechanism. Interconnected pore is observed with Scanning Electron Microscope (SEM) and shows that the amount and area of interconnected pore inside the hydrogel network is increasing as drug dissolution goes on.

  12. In situ observation of a hydrogel-glass interface during sliding friction

    OpenAIRE

    Yamamoto, Tetsurou; Kurokawa, Takayuki; Ahmed, Jamil; Kamita, Gen; Yashima, Shintaro; Furukawa, Yuichiro; Ota, Yuko; Furukawa, Hidemitsu; Gong, Jian Ping

    2014-01-01

    Direct observation of hydrogel contact with a solid surface in water is indispensable for understanding the friction, lubrication, and adhesion of hydrogels under water. However, this is a difficult task since the refractive index of hydrogels is very close to that of water. In this paper, we present a novel method to in situ observe the macroscopic contact of hydrogels with a solid surface based on the principle of critical refraction. This method was applied to investigate the sliding frict...

  13. Photocrosslinked nanocomposite hydrogels from PEG and silica nanospheres: Structural, mechanical and cell adhesion characteristics

    International Nuclear Information System (INIS)

    Gaharwar, Akhilesh K.; Rivera, Christian; Wu, Chia-Jung; Chan, Burke K.; Schmidt, Gudrun

    2013-01-01

    Photopolymerized hydrogels are extensively investigated for various tissue engineering applications, primarily due to their ability to form hydrogels in a minimally invasive manner. Although photocrosslinkable hydrogels provide necessary biological and chemical characteristics to mimic cellular microenvironments, they often lack sufficient mechanical properties. Recently, nanocomposite approaches have demonstrated potential to overcome these deficits by reinforcing the hydrogel network with. In this study, we investigate some physical, chemical, and biological properties of photocrosslinked poly(ethylene glycol) (PEG)-silica hydrogels. The addition of silica nanospheres significantly suppresses the hydration degree of the PEG hydrogels, indicating surface interactions between the silica nanospheres and the polymer chains. No significant change in hydrogel microstructure or average pore size due to the addition of silica nanospheres was observed. However, addition of silica nanospheres significantly increases both the mechanical strength and the toughness of the hydrogel networks. The biological properties of these nanocomposite hydrogels were evaluated by seeding fibroblast cells on the hydrogel surface. While the PEG hydrogels showed minimum cell adhesion, spreading and proliferation, the addition of silica nanospheres enhanced initial cell adhesion, promoted cell spreading and increased the metabolic activity of the cells. Overall, results indicate that the addition of silica nanospheres improves the mechanical stiffness and cell adhesion properties of PEG hydrogels and can be used for biomedical applications that required controlled cell adhesion. - Graphical abstract: Structural, mechanical and biological properties of photocrosslinked nanocomposite hydrogels from silica and poly(ethylene oxide) are investigated. Silica reinforce the hydrogel network and improved mechanical strength. Addition of induces cell adhesion characteristic properties for various

  14. Recent Developments in Thiolated Polymeric Hydrogels for Tissue Engineering Applications.

    Science.gov (United States)

    Gajendiran, Mani; Rhee, Jae-Sung; Kim, Kyobum

    2018-02-01

    This review focuses on the recent strategy in the preparation of thiolated polymers and fabrication of their hydrogel matrices. The mechanism involved in the synthesis of thiolated polymers and fabrication of thiolated polymer hydrogels is exemplified with suitable schematic representations reported in the recent literature. The 2-iminothiolane namely "Traut's reagent" has been widely used for effectively thiolating the natural polymers such as collagen and gelatin, which contain free amino group in their backbone. The free carboxylic acid group containing polymers such as hyaluronic acid and heparin have been thiolated by using the bifunctional molecules such as cysteamine and L-cysteine via N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling reaction. The degree of thiolation in the polymer chain has been widely determined by using Ellman's assay method. The thiolated polymer hydrogels are prepared by disulfide bond formation (or) thiol-ene reaction (or) Michael-type addition reaction. The thiolated polymers such as thiolated gelatin are reacted with polyethylene glycol diacrylate for obtaining interpenetrating polymer network hydrogel scaffolds. Several in vitro cell culture experiments indicate that the developed thiolated polymer hydrogels exhibited biocompatibility and cellular mimicking properties. The developed hydrogel scaffolds efficiently support proliferation and differentiation of various cell types. In the present review article, the thiol-functionalized protein-based biopolymers, carbohydrate-based polymers, and some synthetic polymers have been covered with recently published research articles. In addition, the usage of new thiolated nanomaterials as a crosslinking agent for the preparation of three-dimensional tissue-engineered hydrogels is highlighted.

  15. E-beam crosslinked, biocompatible functional hydrogels incorporating polyaniline nanoparticles

    International Nuclear Information System (INIS)

    Dispenza, C.; Sabatino, M.-A.; Niconov, A.; Chmielewska, D.; Spadaro, G.

    2012-01-01

    PANI aqueous nanocolloids in their acid-doped, inherently conductive form were synthesised by means of suitable water soluble polymers used as stabilisers. In particular, poly(vinyl alcohol) (PVA) or chitosan (CT) was used to stabilise PANI nanoparticles, thus preventing PANI precipitation during synthesis and upon storage. Subsequently, e-beam irradiation of the PANI dispersions has been performed with a 12 MeV Linac accelerator. PVA-PANI nanocolloid has been transformed into a PVA-PANI hydrogel nanocomposite by radiation induced crosslinking of PVA. CT-PANI nanoparticles dispersion, in turn, was added to PVA to obtain wall-to-wall gels, as chitosan mainly undergoes chain scission under the chosen irradiation conditions. While the obtainment of uniform PANI particle size distribution was preliminarily ascertained with laser light scattering and TEM microscopy, the typical porous structure of PVA-based freeze dried hydrogels was observed with SEM microscopy for the hydrogel nanocomposites. UV−visible absorption spectroscopy demonstrates that the characteristic, pH-dependent and reversible optical absorption properties of PANI are conferred to the otherwise optically transparent PVA hydrogels. Selected formulations have been also subjected to MTT assays to prove the absence of cytotoxicity. - Highlights: ► PANI nanocolloids were chemically synthesised in the presence of PVA and chitosan. ► PANI dispersions were transformed into hydrogel nanocomposites by e-beam irradiation. ► Characteristic optical properties of PANI were shown by the nanocomposite hydrogels. ► Absence of cytotoxicity for the nanocomposite hydrogels is demonstrated. ► Results encourage developments for application in biosensing and smart drug delivery.

  16. Stimuli-sensitive hydrogels: A novel ophthalmic drug delivery system

    Directory of Open Access Journals (Sweden)

    Singh Vinod

    2010-01-01

    Full Text Available Background: Stimuli-sensitive hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids on stimulation, such as pH, temperature and ionic change. Aim: To develop hydrogels that are sensitive to stimuli, i.e. pH, in the cul-de-sac of the eye for providing a prolonged effect and increased bioavailability with reduction in frequency of administration. Materials and Methods: Hydrogels were formulated by using timolol maleate as the model drug, polyacrylic acid as the gelling agents, hydroxyl ethyl cellulose as the viscolizer and sodium chloride as the isotonic agent. Stirring of ingredients in pH 4 phosphate buffer at high speed was carried out. The dynamic dialysis technique was used for drug release studies. In vivo study for reduction in intraocular pressure was carried out by using albino rabbits. Statistical Analysis: Drug release studies data were used for statistical analysis in first-order plots, Higuchi plots and Peppas exponential plots. Student t-test was performed for in vivo study. Results: Viscosity of the hydrogel increases from 3.84 cps to 9.54 cps due to change in pH 4 to pH 7.4. The slope value of the Peppas equation was found to be 0.3081, 0.3743 and 0.2964. Up to 80% of drug was released in an 8 h drug release study. Sterile hydrogels with no ocular irritation were obtained. Conclusions: Hydrogels show increase in viscosity due to change in pH. Hydrogels were therapeutically effacious, stable, non-irritant and showed Fickian diffusion. In vivo results clearly show a prolonged reduction in intraocular pressure, which was helpful for reduction in the frequency of administration.

  17. 21 CFR 878.4022 - Hydrogel wound dressing and burn dressing.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hydrogel wound dressing and burn dressing. 878.4022 Section 878.4022 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Hydrogel wound dressing and burn dressing. (a) Identification. A hydrogel wound dressing is a sterile or...

  18. Study of chemically induced pressure generation of hydrogels under isochoric conditions using a microfabricated device

    NARCIS (Netherlands)

    Herber, S.; Eijkel, Jan C.T.; Olthuis, Wouter; Bergveld, Piet; van den Berg, Albert

    2004-01-01

    A method is proposed to study the behavior of stimulus-sensitive hydrogels under isochoric conditions. Freedom of swell movement of such a hydrogel was restricted in all directions by enclosing the hydrogel between a micropressure sensor and a porous cover. Water and external stimuli can be applied

  19. Thermosensitive copolymeric hydrogels with the regulated temperature of a phase transition

    International Nuclear Information System (INIS)

    Samchenko, Yu.M.; Konovalova, V.V.; Korotich, E.I.; Poltoratskaya, T.P.; Pobegaj, A.A.; Burban, A.F.; Ul'berg, Z.R.; Samchenko, Yu.M.; Konovalova, V.V.; Korotich, E.I.; Poltoratskaya, T.P.; Pobegaj, A.A.; Burban, A.F.; Ul'berg, Z.R.

    2011-01-01

    The work is devoted to the methods of obtaining the thermosensitive copolymeric hydrogels based on the NIPAAm with acrylic acid and its derivatives such as acrylamide, acrylonitrile, and methylacrylate. The mechanisms of thermoinitiated phase transitions in hydrogel matrices and the regularities of the thermoinitiated release of model compounds and drugs (aniline, novocaine, and sodium diclofenac) from copolymeric hydrogel are investigated.

  20. An Injectable Composite Gelatin Hydrogel with pH Response Properties

    Directory of Open Access Journals (Sweden)

    Baoguo Chen

    2017-01-01

    Full Text Available On account of minimally invasive procedure and of filling irregular defects of tissues, injectable hydrogels are increasingly attractive in biomedical fields. However, traditional hydrogel formed by simple physical interaction or in situ crosslinking had inevitably some drawbacks such as low mechanical strength and lack of multifunctional properties. Though many investigations had successfully modified traditional injectable hydrogel to obtain both mechanical and functional properties, an acetalated β-cyclodextrin (Ac-β-CD nanoparticle composite injectable hydrogel designed in the research was another effective and efficient choice to solve the drawbacks. First of all, gelatin derivative (G-AA and Ac-β-CD were synthesized to prepare hydrogel and nanoparticle, respectively. In order to ensure good compatibility between nanoparticle and macromonomer and provide crosslink points between nanoparticle and macromonomer, G-AA was simultaneously functionalized onto the surface of Ac-β-CD nanoparticle during the fabrication of Ac-β-CD nanoparticle using one-step method. Finally, injectable composite hydrogel was obtained by photoinitiated polymerization in situ. Hydrogel properties like gelation time and swelling ratio were investigated. The viscoelastic behavior of hydrogels confirmed that typical characteristics of crosslinked elastomer for all hydrogel and nanoparticle in hydrogel could improve the mechanical property of hydrogel. Moreover, the transparency with time had verified obvious acid-response properties of hydrogels.

  1. Osteogenic differentiation of human adipose-derived mesenchymal stem cells on gum tragacanth hydrogel.

    Science.gov (United States)

    Haeri, Seyed Mohammad Jafar; Sadeghi, Yousef; Salehi, Mohammad; Farahani, Reza Masteri; Mohsen, Nourozian

    2016-05-01

    Currently, natural polymer based hydrogels has attracted great attention of orthopedic surgeons for application in bone tissue engineering. With this aim, osteoinductive capacity of Gum Tragacanth (GT) based hydrogel was compared to collagen hydrogel and tissue culture plate (TCPS). For this purpose, adipose-derived mesenchymal stem cells (AT-MSCs) was cultured on the hydrogels and TCPS and after investigating the biocompatibility of hydrogels using MTT assay, osteoinductivity of hydrogels were evaluated using pan osteogenic markers such as Alizarin red staining, alkaline phosphatase (ALP) activity, calcium content and osteo-related genes. Increasing proliferation trend of AT-MSCs on GT hydrogel demonstrated that TG has no-cytotoxicity and can even be better than the other groups i.e., highest proliferation at day 5. GT hydrogel displayed highest ALP activity and mineralization when compared to the collagen hydrogel and TCPS. Relative gene expression levels have demonstrated that highest expression of Runx2, osteonectin and osteocalcin in the cells cultured GT hydrogel but the expression of collagen type-1 remains constant in hydrogels. Above results demonstrate that GT hydrogel could be an appropriate scaffold for accelerating and supporting the adhesion, proliferation and osteogenic differentiation of stem cells which further can be used for orthopedic applications. Copyright © 2016. Published by Elsevier Ltd.

  2. Bioinspired, biomimetic, double-enzymatic mineralization of hydrogels for bone regeneration with calcium carbonate

    DEFF Research Database (Denmark)

    Lopez-Heredia, Marco A.; Łapa, Agata; Mendes, Ana Carina Loureiro

    2017-01-01

    Hydrogels are popular materials for tissue regeneration. Incorporation of biologically active substances, e.g. enzymes, is straightforward. Hydrogel mineralization is desirable for bone regeneration. Here, hydrogels of Gellan Gum (GG), a biocompatible polysaccharide, were mineralized biomimetically...... of osteoblast-like cells....

  3. Hydrogel based cartilaginous tissue regeneration: recent insights and technologies.

    Science.gov (United States)

    Chuah, Yon Jin; Peck, Yvonne; Lau, Jia En Josias; Hee, Hwan Tak; Wang, Dong-An

    2017-03-28

    Hydrogels have been extensively employed as an attractive biomaterial to address numerous existing challenges in the fields of regenerative medicine and research because of their unique properties such as the capability to encapsulate cells, high water content, ease of modification, low toxicity, injectability, in situ spatial fit and biocompatibility. These inherent properties have created many opportunities for hydrogels as a scaffold or a cell/drug carrier in tissue regeneration, especially in the field of cartilaginous tissue such as articular cartilage and intervertebral discs. A concise overview of the anatomy/physiology of these cartilaginous tissues and their pathophysiology, epidemiology and existing clinical treatments will be briefly described. This review article will discuss the current state-of-the-art of various polymers and developing strategies that are explored in establishing different technologies for cartilaginous tissue regeneration. In particular, an innovative approach to generate scaffold-free cartilaginous tissue via a transient hydrogel scaffolding system for disease modeling to pre-clinical trials will be examined. Following that, the article reviews numerous hydrogel-based medical implants used in clinical treatment of osteoarthritis and degenerated discs. Last but not least, the challenges and future directions of hydrogel based medical implants in the regeneration of cartilaginous tissue are also discussed.

  4. Novel epoxy activated hydrogels for solving lactose intolerance.

    Science.gov (United States)

    Elnashar, Magdy M M; Hassan, Mohamed E

    2014-01-01

    "Lactose intolerance" is a medical problem for almost 70% of the world population. Milk and dairy products contain 5-10% w/v lactose. Hydrolysis of lactose by immobilized lactase is an industrial solution. In this work, we succeeded to increase the lactase loading capacity to more than 3-fold to 36.3 U/g gel using epoxy activated hydrogels compared to 11 U/g gel using aldehyde activated carrageenan. The hydrogel's mode of interaction was proven by FTIR, DSC, and TGA. The high activity of the epoxy group was regarded to its ability to attach to the enzyme's -SH, -NH, and -OH groups, whereas the aldehyde group could only bind to the enzyme's -NH2 group. The optimum conditions for immobilization such as epoxy chain length and enzyme concentration have been studied. Furthermore, the optimum enzyme conditions were also deliberated and showed better stability for the immobilized enzyme and the Michaelis constants, K m and V max, were doubled. Results revealed also that both free and immobilized enzymes reached their maximum rate of lactose conversion after 2 h, albeit, the aldehyde activated hydrogel could only reach 63% of the free enzyme. In brief, the epoxy activated hydrogels are more efficient in immobilizing more enzymes than the aldehyde activated hydrogel.

  5. Hofmeister effects on the glucose oxidase hydrogel-modified electrode

    International Nuclear Information System (INIS)

    Suzuki, Aimi; Tsujimura, Seiya

    2016-01-01

    We describe the consistent effect of salts in the electrolyte solution on glucose oxidation current production in the redox hydrogel-modified electrode containing glucose oxidase as an electrocatalyst and Os complex mediator. The ions affect not only on the electron transfer between the enzyme and the Os complex, but also on the hydrogel structure. This study found that the degree of the effect can be characterized by Hofmeister series. The relative decrease in oxidization current is the lowest in the middle of the Hofmeister series, and increases monotonically on either side. An increase of ionic strength inhibits the electron transfer from the active site of glucose oxidase to Os complex. In addition to this, the kosmotropic anions, which are strongly hydrated, caused hydrogel deswelling (shrinking). The more chaotropic an ion is, the more it adsorbs to uncharged parts of polymer/enzyme with dispersion force, and the swelling of the hydrogel decreases the catalytic current. This study impacts the design of hydrogel electrode and selection of electrolyte ions for bioelectronic applications.

  6. Interfacial self-healing of nanocomposite hydrogels: Theory and experiment

    Science.gov (United States)

    Wang, Qiming; Gao, Zheming; Yu, Kunhao

    2017-12-01

    Polymers with dynamic bonds are able to self-heal their fractured interfaces and restore the mechanical strengths. It is largely elusive how to analytically model this self-healing behavior to construct the mechanistic relationship between the self-healing properties (e.g., healed interfacial strength and equilibrium healing time) and the material compositions and healing conditions. Here, we take a self-healable nanocomposite hydrogel as an example to illustrate an interfacial self-healing theory for hydrogels with dynamic bonds. In the theory, we consider the free polymer chains diffuse across the interface and reform crosslinks to bridge the interface. We analytically reveal that the healed strengths of nanocomposite hydrogels increase with the healing time in an error-function-like form. The equilibrium self-healing time of the full-strength recovery decreases with the temperature and increases with the nanoparticle concentration. We further analytically reveal that the healed interfacial strength decreases with increasing delaying time before the healing process. The theoretical results quantitatively match with our experiments on nanosilica hydrogels, and also agree well with other researchers' experiments on nanoclay hydrogels. We expect that this theory would open promising avenues for quantitative understanding of the self-healing mechanics of various polymers with dynamic bonds, and offer insights for designing high-performance self-healing polymers.

  7. Synthesis of silver nanoparticles in hydrogels crosslinked by ionizing radiation

    International Nuclear Information System (INIS)

    Alcantara, Maria Tania S.; Oliani, Washington L.; Brant, Antonio J.C.; Oliveira, Maria Jose A. de; Riella, Humberto Gracher; Lugao, Ademar B.

    2013-01-01

    Hydrogel is defined as a polymeric material which exhibits the ability to swell and retain a significant fraction of water within its structure without dissolving the polymeric network. Silver nanoparticles (AgNPs) are used in a range of medicinal products based on hydrogels and diverse other products due to their antibacterial properties at low concentrations. The use of ionizing radiation in the production process of hydrogels of poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) in aqueous solutions enables the crosslinking of their polymer chains. If polymer solutions contain Ag + ions, these can be reduced radiolytically to nanocrystalline silver. The objective of this study was to investigate the reduction of Ag + ions by gamma-irradiation for the synthesis of AgNPs in hydrogels of PVA and PVP as main polymers and to make a comparison of the performance of the two polymeric matrices, chiefly focusing on the effect of the AgNPs' synthesis on the crosslinking of both polymers. The properties of the hydrogel matrices obtained were evaluated from tests of gel fraction, swelling in water, and stress-strain. The results of mechanical properties of PVA matrix were higher than those of PVP one whereas the latter exhibited a higher swelling degree. The reduction of silver ions was confirmed by UV-visible absorption spectrum, whose characteristics also indicated the formation of silver nanoparticles in both arrays. (author)

  8. Drug-sensing hydrogels for the inducible release of biopharmaceuticals

    Science.gov (United States)

    Ehrbar, Martin; Schoenmakers, Ronald; Christen, Erik H.; Fussenegger, Martin; Weber, Wilfried

    2008-10-01

    Drug-dependent dissociation or association of cellular receptors represents a potent pharmacologic mode of action for regulating cell fate and function. Transferring the knowledge of pharmacologically triggered protein-protein interactions to materials science will enable novel design concepts for stimuli-sensing smart hydrogels. Here, we show the design and validation of an antibiotic-sensing hydrogel for the trigger-inducible release of human vascular endothelial growth factor. Genetically engineered bacterial gyrase subunit B (GyrB) (ref. 4) coupled to polyacrylamide was dimerized by the addition of the aminocoumarin antibiotic coumermycin, resulting in hydrogel formation. Addition of increasing concentrations of clinically validated novobiocin (Albamycin) dissociated the GyrB subunits, thereby resulting in dissociation of the hydrogel and dose- and time-dependent liberation of the entrapped protein pharmaceutical VEGF121 for triggering proliferation of human umbilical vein endothelial cells. Pharmacologically controlled hydrogels have the potential to fulfil the promises of stimuli-sensing materials as smart devices for spatiotemporally controlled delivery of drugs within the patient.

  9. Hybrid hydrogels produces by ionizing radiation technique for drug delivery

    International Nuclear Information System (INIS)

    Oliveira, M.J.A.; Parra, D.F.; Lugao, A.B.; Amato, V.S.

    2011-01-01

    Complete text of publication follows. Interest in the preparation of biocompatible hydrogels with various properties has increased considerably in recent years due to their versatile applications in biomedicine, biotechnology, pharmacy, agriculture and controlled release of drugs. The use of hydrogels matrices for particular drug-release applications has been investigated with the synthesis of modified polymeric hydrogel of PVAl, PEG and 0.5, 1.0 and 1.5% nano-clay. They were processed using gamma radiation from Cobalt-60 source at 25 kGy dose. The characterization of the hydrogels was conducted and toxicity was evaluated. The dried hydrogel was analyzed for thermogravimetry analysis (TGA), infrared spectroscopic analysis (FTIR), swelling in solutions of different pH and gel determinations. The membranes have no toxicity and the gel content reveals the reticulation. The nano-clay influences directly the equilibrium swelling. Acknowledgement: Support by FAPESP 09/50926-1, FAPESP Process no. 2009/18627-4 CNPq Process no. 310849/2009-8, CAPES, IPEN/CNEN.

  10. Applanation tonometry in silicone hydrogel contact lens wearers.

    Science.gov (United States)

    Allen, R J; Dev Borman, A; Saleh, G M

    2007-12-01

    Previous studies have investigated intraocular pressure (IOP) measurements through conventional soft (hydrogel) therapeutic contact lenses, and have found that an accurate IOP can be recorded in normal eyes, and in eyes with abnormal anterior segments. The IOP measurement through soft contact lenses may be affected by the water content and centre thickness of the lens. Silicone hydrogel contact lenses are now being used as therapeutic contact lenses due to their high oxygen permeability. The purpose of this study is to investigate if IOP can be accurately measured in a subject wearing a silicone hydrogel contact lens. In a cohort study, the IOP was measured with a Goldmann applanation tonometer without a contact lens and then repeated with a hydrogel contact lens in situ. The IOP of 20 eyes of 10 volunteers with no ocular pathology was measured. The mean difference (+/-S.D.) found between IOP measurement with (mean 15.55+/-1.70 mmHg) and without (mean 16.05+/-1.90 mmHg) contact lens was found to be -0.5+/-0.89 mmHg. Statistical analysis was performed which revealed a correlation coefficient of 0.89. No significant statistical difference was found between the two groups with paired t-test (p=0.19). Accurate measurement of IOP by applanation tonometry can be achieved through a silicone hydrogel contact lens.

  11. Performance and biocompatibility of extremely tough alginate/polyacrylamide hydrogels.

    Science.gov (United States)

    Darnell, Max C; Sun, Jeong-Yun; Mehta, Manav; Johnson, Christopher; Arany, Praveen R; Suo, Zhigang; Mooney, David J

    2013-11-01

    Although hydrogels now see widespread use in a host of applications, low fracture toughness and brittleness have limited their more broad use. As a recently described interpenetrating network (IPN) of alginate and polyacrylamide demonstrated a fracture toughness of ≈ 9000 J/m(2), we sought to explore the biocompatibility and maintenance of mechanical properties of these hydrogels in cell culture and in vivo conditions. These hydrogels can sustain a compressive strain of over 90% with minimal loss of Young's Modulus as well as minimal swelling for up to 50 days of soaking in culture conditions. Mouse mesenchymal stem cells exposed to the IPN gel-conditioned media maintain high viability, and although cells exposed to conditioned media demonstrate slight reductions in proliferation and metabolic activity (WST assay), these effects are abrogated in a dose-dependent manner. Implantation of these IPN hydrogels into subcutaneous tissue of rats for 8 weeks led to mild fibrotic encapsulation and minimal inflammatory response. These results suggest the further exploration of extremely tough alginate/PAAM IPN hydrogels as biomaterials. © 2013 Elsevier Ltd. All rights reserved.

  12. Extracellular matrix-derived hydrogels for dental stem cell delivery.

    Science.gov (United States)

    Viswanath, Aiswarya; Vanacker, Julie; Germain, Loïc; Leprince, Julian G; Diogenes, Anibal; Shakesheff, Kevin M; White, Lisa J; des Rieux, Anne

    2017-01-01

    Decellularized mammalian extracellular matrices (ECM) have been widely accepted as an ideal substrate for repair and remodelling of numerous tissues in clinical and pre-clinical studies. Recent studies have demonstrated the ability of ECM scaffolds derived from site-specific homologous tissues to direct cell differentiation. The present study investigated the suitability of hydrogels derived from different source tissues: bone, spinal cord and dentine, as suitable carriers to deliver human apical papilla derived mesenchymal stem cells (SCAP) for spinal cord regeneration. Bone, spinal cord, and dentine ECM hydrogels exhibited distinct structural, mechanical, and biological characteristics. All three hydrogels supported SCAP viability and proliferation. However, only spinal cord and bone derived hydrogels promoted the expression of neural lineage markers. The specific environment of ECM scaffolds significantly affected the differentiation of SCAP to a neural lineage, with stronger responses observed with spinal cord ECM hydrogels, suggesting that site-specific tissues are more likely to facilitate optimal stem cell behavior for constructive spinal cord regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 319-328, 2017. © 2016 Wiley Periodicals, Inc.

  13. Microfabrication of biocompatible hydrogels by proton beam writing

    Science.gov (United States)

    Nagasawa, Naotsugu; Kimura, Atsushi; Idesaki, Akira; Yamada, Naoto; Koka, Masashi; Satoh, Takahiro; Ishii, Yasuyuki; Taguchi, Mitsumasa

    2017-10-01

    Functionalization of biocompatible materials is expected to be widely applied in biomedical engineering and regenerative medicine fields. Hydrogel has been expected as a biocompatible scaffold which support to keep an organ shape during cell multiplying in regenerative medicine. Therefore, it is important to understanding a surface microstructure (minute shape, depth of flute) and a chemical characteristic of the hydrogel affecting the cell culture. Here, we investigate the microfabrication of biocompatible polymeric materials, such as the water-soluble polysaccharide derivatives hydroxypropyl cellulose and carboxymethyl cellulose, by use of proton beam writing (PBW). These polymeric materials were dissolved thoroughly in pure water using a planetary centrifugal mixer, and a sample sheet (1 mm thick) was formed on polyethylene terephthalate (PET) film. Crosslinking to form hydrogels was induced using a 3.0 MeV focused proton beam from the single-ended accelerator at Takasaki Ion Accelerators for Advanced Radiation Application. The aqueous samples were horizontally irradiated with the proton beam through the PET cover film, and then rinsed with deionized water. Microstructured hydrogels were obtained on the PET film using the PBW technique without toxic crosslinking reagents. Cell adhesion and proliferation on the microfabricated biocompatible hydrogels were investigated. Microfabrication of HPC and CMC by the use of PBW is expected to produce new biocompatible materials that can be applied in biological and medical applications.

  14. Hydrogels for efficient light delivery in optogenetic applications

    Science.gov (United States)

    Johannsmeier, S.; Torres, M. L.; Ripken, T.; Heinemann, D.; Heisterkamp, A.

    2018-02-01

    Light-based therapies have been established for various indications, such as skin conditions, cancer or neonatal jaundice. Advances in the field of optogenetics open up new horizons for light-tissue interactions with an organism-wide impact. Excitable tissues, such as nerve and muscle tissues, can be controlled by light after the introduction of light-sensitive ion channels. Since these organs are generally not easily accessible to illumination in vivo, there is an increasing need for effective biocompatible waveguides for light delivery. These devices not only have to guide and distribute the light as desired with minimal losses, they should also mimic the mechanical properties of the surrounding tissue to ensure compatibility. In this project, we are tuning the properties of hydrogels from poly(ethylene glycol) derivatives to achieve compatibility with muscle tissue as well as optimal light guiding and distribution for optogenetic applications at the heart. The excitation light is coupled into the hydrogel with a biocompatible fiber. Properties of the hydrogel are mainly tuned by monomer length and concentration. Total reflection can be achieved by embedding a fiber-like hydrogel with a high refractive index into a second, low refractive index gel. Different geometries and scattering microparticles are used for light distribution in a flat gel patch. Targeted cell attachment can be achieved by introducing a protein layer to the otherwise bioinert gel. After optimization, the hydrogel may be used to deliver light for the excitation of genetically altered cardiomyocytes for controlled contraction.

  15. Biocompatible Amphiphilic Hydrogel-Solid Dimer Particles as Colloidal Surfactants.

    Science.gov (United States)

    Chen, Dong; Amstad, Esther; Zhao, Chun-Xia; Cai, Liheng; Fan, Jing; Chen, Qiushui; Hai, Mingtan; Koehler, Stephan; Zhang, Huidan; Liang, Fuxin; Yang, Zhenzhong; Weitz, David A

    2017-12-26

    Emulsions of two immiscible liquids can slowly coalesce over time when stabilized by surfactant molecules. Pickering emulsions stabilized by colloidal particles can be much more stable. Here, we fabricate biocompatible amphiphilic dimer particles using a hydrogel, a strongly hydrophilic material, and achieve large contrast in the wetting properties of the two bulbs, resulting in enhanced stabilization of emulsions. We generate monodisperse single emulsions of alginate and shellac solution in oil using a flow-focusing microfluidics device. Shellac precipitates from water and forms a solid bulb at the periphery of the droplet when the emulsion is exposed to acid. Molecular interactions result in amphiphilic dimer particles that consist of two joined bulbs: one hydrogel bulb of alginate in water and the other hydrophobic bulb of shellac. Alginate in the hydrogel compartment can be cross-linked using calcium cations to obtain stable particles. Analogous to surfactant molecules at the interface, the resultant amphiphilic particles stand at the water/oil interface with the hydrogel bulb submerged in water and the hydrophobic bulb in oil and are thus able to stabilize both water-in-oil and oil-in-water emulsions, making these amphiphilic hydrogel-solid particles ideal colloidal surfactants for various applications.

  16. Compatibility study of a parenteral microdose polyethylene glycol formulation in medical devices and identification of degradation impurity by 2D-LC/MS.

    Science.gov (United States)

    Dai, Lulu; Yeh, Geoffrey K; Ran, Yingqing; Yehl, Peter; Zhang, Kelly

    2017-04-15

    Polyethylene glycol (PEG) based formulation and polyvinylchloride (PVC) tubing are frequently used for drug delivery and administration. The compatibility of a parenteral drug microdose formulation in intravenous infusion (IV) devices was studied to support the clinical determination of absolute bioavailability by the microdosing method. The investigational microdose formulation containing PEG was found prone to significant loss of potency within hours of storage in the PVC IV tubing due to degradation. Degradation occurred only when both PEG and PVC tubing were present. The degradation product could not be detected by LC/MS due to the significant interference from the high concentration of PEG (4%) matrix and the extremely low level of drug (0.6ppm). To obtain structural information of the degradation impurity and understand the cause of the degradation, a simple heart-cutting 2D-LC/MS approach was utilized to effectively separate the impurity from the complex PEG oligomers and overcome the matrix interference, enabling mass spectrometric analysis of the impurity. An oxidation- dominated mechanism was proposed in which the combination of PEG auto-oxidation and dehydrochlorination of the PVC tubing yielded an oxidative environment that enhanced radical propagation and accelerated degradation of the investigational parent drug. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Preparation and properties of GO-PVA composite hydrogel with oriented structure

    Science.gov (United States)

    Liu, Huanqing; Zhang, Gongzheng; Li, Huanjun

    2017-03-01

    We fabricated GO-PVA composite hydrogels with oriented structure by directional freezing and repeated freeze-thawing, which owned superior mechanical property and thermostability than PVA hydrogel. Due to physical interactions such as hydrogen bonding between surface of GO and PVA chains, GO-PVA composite hydrogel possessed higher crosslinking density and smaller pore size and can resist higher temperature and stronger force from outside than PVA hydrogel. These unique properties will endow GO-PVA hydrogel with greater potential application in biomedical materials.

  18. Polyisocyanopeptide hydrogels: A novel thermo-responsive hydrogel supporting pre-vascularization and the development of organotypic structures.

    Science.gov (United States)

    Zimoch, Jakub; Padial, Joan Simó; Klar, Agnes S; Vallmajo-Martin, Queralt; Meuli, Martin; Biedermann, Thomas; Wilson, Christopher J; Rowan, Alan; Reichmann, Ernst

    2018-04-01

    Molecular and mechanical interactions with the 3D extracellular matrix are essential for cell functions such as survival, proliferation, migration, and differentiation. Thermo-responsive biomimetic polyisocyanopeptide (PIC) hydrogels are promising new candidates for 3D cell, tissue, and organ cultures. This is a synthetic, thermo-responsive and stress-stiffening material synthesized via polymerization of the corresponding monomers using a nickel perchlorate as a catalyst. It can be tailored to meet various demands of cells by modulating its stiffness and through the decoration of the polymer with short GRGDS peptides using copper free click chemistry. These peptides make the hydrogels biocompatible by mimicking the binding sites of certain integrins. This study focuses on the optimization of the PIC polymer properties for efficient cell, tissue and organ development. Screening for the optimal stiffness of the hydrogel and the ideal concentration of the GRGDS ligand conjugated with the polymer, enabled cell proliferation, migration and differentiation of various primary cell types of human origin. We demonstrate that fibroblasts, endothelial cells, adipose-derived stem cells and melanoma cells, do survive, thrive and differentiate in optimized PIC hydrogels. Importantly, these hydrogels support the spontaneous formation of complex structures like blood capillaries in vitro. Additionally, we utilized the thermo-responsive properties of the hydrogels for a rapid and gentle recovery of viable cells. Finally, we show that organotypic structures of human origin grown in PIC hydrogels can be successfully transplanted subcutaneously onto immune-compromised rats, on which they survive and integrate into the surrounding tissue. Molecular and mechanical interactions with the surrounding environment are essential for cell functions. Although 2D culture systems greatly contributed to our understanding of complex biological phenomena, they cannot substitute for crucial

  19. Desmosine-Inspired Cross-Linkers for Hyaluronan Hydrogels

    Science.gov (United States)

    Hagel, Valentin; Mateescu, Markus; Southan, Alexander; Wegner, Seraphine V.; Nuss, Isabell; Haraszti, Tamás; Kleinhans, Claudia; Schuh, Christian; Spatz, Joachim P.; Kluger, Petra J.; Bach, Monika; Tussetschläger, Stefan; Tovar, Günter E. M.; Laschat, Sabine; Boehm, Heike

    2013-06-01

    We designed bioinspired cross-linkers based on desmosine, the cross-linker in natural elastin, to prepare hydrogels with thiolated hyaluronic acid. These short, rigid cross-linkers are based on pyridinium salts (as in desmosine) and can connect two polymer backbones. Generally, the obtained semi-synthetic hydrogels are form-stable, can withstand repeated stress, have a large linear-elastic range, and show strain stiffening behavior typical for biopolymer networks. In addition, it is possible to introduce a positive charge to the core of the cross-linker without affecting the gelation efficiency, or consequently the network connectivity. However, the mechanical properties strongly depend on the charge of the cross-linker. The properties of the presented hydrogels can thus be tuned in a range important for engineering of soft tissues by controlling the cross-linking density and the charge of the cross-linker.

  20. Development of Acne therapeutic hydrogel patches by radiation technology

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Younmook; Nho, Youngchang; Gwon, Huijeong; Park, Jongseok; Kim, Jinkyu; Kim, Yongsoo

    2012-04-15

    In this project, hydrogel patches containing herbal extracts mixture were developed by radiation technology for acne treatment. Propionibacterium acnes (P. acnes), one of the anaerobic bacterium, is the cause of inflammatory acne. To find novel mediation for inflammation of P. acnes, we confirmed the anti-bacterial and anti-inflammatory activities of several herbal extracts against P. acnes. The water extracts from five dried herbs, Phellodendron amurense Rupr., Paeonia lactiflora Pallas., Houttuynia cordata Thumb., Agrimonia pilosa Ledeb. and Glycyrrhiza uralensis Fisch., were mixed into biocompatible polymers and irradiated by using gamma-ray to prepare hydrogels. The hydrogels containing herbal extracts mixture initiated to decrease the growth of P. acnes and reduced the production of pro-inflammatory cytokines, TNF-{alpha}, IL-8, IL-1{beta} and IL-6, in experiment with human monocytic THP-1 cells treated with heat-killed P. acnes at 1 mg/ml of mixture concentration.

  1. Hydrogels for in situ encapsulation of biomimetic membrane arrays

    DEFF Research Database (Denmark)

    Ibragimova, Sania; Jensen, Karin Bagger Stibius; Szewczykowski, Piotr Przemyslaw

    2012-01-01

    to chemically initiated hydrogels; however, for all hydrogels the permeability was several-fold higher than the water permeability of conventional reverse osmosis (RO) membranes. Lifetimes of freestanding BLM arrays in gel precursor solutions were short compared to arrays formed in buffer. However, polymerizing......Hydrogels are hydrophilic, porous polymer networks that can absorb up to thousands of times their own weight in water. They have many potential applications, one of which is the encapsulation of freestanding black lipid membranes (BLMs) for novel separation technologies or biosensor applications....... We investigated gels for in situ encapsulation of multiple BLMs formed across apertures in a hydrophobic ethylene tetrafluoroethylene (ETFE) support. The encapsulation gels consisted of networks of poly(ethylene glycol)-dimethacrylate or poly(ethylene glycol)-diacrylate polymerized using either...

  2. Pseudo-thermosetting chitosan hydrogels for biomedical application.

    Science.gov (United States)

    Berger, J; Reist, M; Chenite, A; Felt-Baeyens, O; Mayer, J M; Gurny, R

    2005-01-06

    To prepare transparent chitosan/beta-glycerophosphate (betaGP) pseudo-thermosetting hydrogels, the deacetylation degree (DD) of chitosan has been modified by reacetylation with acetic anhydride. Two methods (I and II) of reacetylation have been compared and have shown that the use of previously filtered chitosan, dilution of acetic anhydride and reduction of temperature in method II improves efficiency and reproducibility. Chitosans with DD ranging from 35.0 to 83.2% have been prepared according to method II under homogeneous and non-homogeneous reacetylation conditions and the turbidity of chitosan/betaGP hydrogels containing homogeneously or non-homogeneously reacetylated chitosan has been investigated. Turbidity is shown to be modulated by the DD of chitosan and by the homogeneity of the medium during reacetylation, which influences the distribution mode of the chitosan monomers. The preparation of transparent chitosan/betaGP hydrogels requires a homogeneously reacetylated chitosan with a DD between 35 and 50%.

  3. Mediating conducting polymer growth within hydrogels by controlling nucleation

    Directory of Open Access Journals (Sweden)

    A. J. Patton

    2015-01-01

    Full Text Available This study examines the efficacy of primary and secondary nucleation for electrochemical polymerisation of conductive polymers within poly(vinyl alcohol methacrylate hydrogels. The two methods of nucleation investigated were a primary heterogeneous mechanism via introduction of conductive bulk metallic glass (Mg64Zn30Ca5Na1 particles and a secondary mechanism via introduction of “pre-polymerised” conducting polymer within the hydrogel (PEDOT:PSS. Evidence of nucleation was not seen in the bulk metallic glass loaded gels, however, the PEDOT:PSS loaded gels produced charge storage capacities over 15 mC/cm2 when sufficient polymer was loaded. These studies support the hypothesis that secondary nucleation is an efficient approach to producing stand-alone conducting hydrogels.

  4. Enhanced intratumoral uptake of quantum dots concealed within hydrogel nanoparticles

    International Nuclear Information System (INIS)

    Nair, Ashwin; Shen Jinhui; Thevenot, Paul; Zou Ling; Tang Liping; Cai Tong; Hu Zhibing

    2008-01-01

    Effective nanomedical devices for tumor imaging and drug delivery are not yet available. In an attempt to construct a more functional device for tumor imaging, we have embedded quantum dots (which have poor circulatory behavior) within hydrogel nanoparticles made of poly-N-isopropylacrylamide. We found that the hydrogel encapsulated quantum dots are more readily taken up by cultured tumor cells. Furthermore, in a melanoma model, hydrogel encapsulated quantum dots also preferentially accumulate in the tumor tissue compared with normal tissue and have ∼16-fold greater intratumoral uptake compared to non-derivatized quantum dots. Our results suggest that these derivatized quantum dots, which have greatly improved tumor localization, may enhance cancer monitoring and chemotherapy.

  5. Development of Acne therapeutic hydrogel patches by radiation technology

    International Nuclear Information System (INIS)

    Lim, Younmook; Nho, Youngchang; Gwon, Huijeong; Park, Jongseok; Kim, Jinkyu; Kim, Yongsoo

    2012-04-01

    In this project, hydrogel patches containing herbal extracts mixture were developed by radiation technology for acne treatment. Propionibacterium acnes (P. acnes), one of the anaerobic bacterium, is the cause of inflammatory acne. To find novel mediation for inflammation of P. acnes, we confirmed the anti-bacterial and anti-inflammatory activities of several herbal extracts against P. acnes. The water extracts from five dried herbs, Phellodendron amurense Rupr., Paeonia lactiflora Pallas., Houttuynia cordata Thumb., Agrimonia pilosa Ledeb. and Glycyrrhiza uralensis Fisch., were mixed into biocompatible polymers and irradiated by using gamma-ray to prepare hydrogels. The hydrogels containing herbal extracts mixture initiated to decrease the growth of P. acnes and reduced the production of pro-inflammatory cytokines, TNF-α, IL-8, IL-1β and IL-6, in experiment with human monocytic THP-1 cells treated with heat-killed P. acnes at 1 mg/ml of mixture concentration

  6. Phytase-mediated enzymatic mineralization of chitosan-enriched hydrogels

    DEFF Research Database (Denmark)

    Lišková, Jana; Douglas, Timothy E.L.; Wijnants, Robbe

    2018-01-01

    Hydrogels mineralized with calcium phosphate (CaP) are increasingly popular bone regeneration biomaterials. Mineralization can be achieved by phosphatase enzyme incorporation and incubation in calcium glycerophosphate (CaGP). Gellan gum (GG) hydrogels containing the enzyme phytase and chitosan...... oligomer were mineralized in CaGP solution and characterized with human osteoblast-like MG63 cells and adipose tissue-derived stem cells (ADSC). Phytase induced CaP formation. Chitosan concentration determined mineralization extent and hydrogel mechanical reinforcement. Phytase-induced mineralization...... promoted MG63 adhesion and proliferation, especially in the presence of chitosan, and was non-toxic to MG63 cells (with and without chitosan). ADSC adhesion and proliferation were poor without mineralization. Chitosan did not affect ADSC osteogenic differentiation....

  7. Comparison of chitosan nanoparticles and chitosan hydrogels for vaccine delivery

    DEFF Research Database (Denmark)

    Gordon, Sarah; Saupe, Anne; McBurney, Warren

    2008-01-01

    In this work the potential of chitosan nanoparticles (CNP) and thermosensitive chitosan hydrogels as particulate and sustained release vaccine delivery systems was investigated. CNP and chitosan hydrogels were prepared, loaded with the model protein antigen ovalbumin (OVA) and characterised...... of the release of fluorescently-labelled OVA (FITC-OVA) from CNP and chitosan hydrogels in-vitro showed that approximately 50% of the total protein was released from CNP within a period of ten days; release of antigen from chitosan gel occurred in a more sustained manner, with ... released after 10 days. The slow release from gel formulations may be explained by the strong interactions of the protein with chitosan. While OVA-loaded CNP showed no significant immunogenicity, formulations of OVA in chitosan gel were able to stimulate both cell-mediated and humoral immunity in-vivo....

  8. Synthesis of hydrogel via click chemistry for DNA electrophoresis.

    Science.gov (United States)

    Finetti, Chiara; Sola, Laura; Elliott, Jim; Chiari, Marcella

    2017-09-01

    This work introduces a novel sieving gel for DNA electrophoresis using a classical click chemistry reaction, the copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC), to cross-link functional polymer chains. The efficiency of this reaction provides, under mild conditions, hydrogels with near-ideal network connectivity and improved physical properties. Hydrogel formation via click chemistry condensation of functional polymers does not involve the use of toxic monomers and UV initiation. The performance of the new hydrogel in the separation of double stranded DNA fragments was evaluated in the 2200 TapeStation system, an analytical platform, recently introduced by Agilent that combines the advantages of CE in terms of miniaturization and automation with the simplicity of use of slab gel electrophoresis. The click gel enables addition of florescent dyes prior to electrophoresis with considerable improvement of resolution and separation efficiency over conventional cross-linked polyacrylamide gels. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Micropillar arrays enabling single microbial cell encapsulation in hydrogels.

    Science.gov (United States)

    Park, Kyun Joo; Lee, Kyoung G; Seok, Seunghwan; Choi, Bong Gill; Lee, Moon-Keun; Park, Tae Jung; Park, Jung Youn; Kim, Do Hyun; Lee, Seok Jae

    2014-06-07

    Single microbial cell encapsulation in hydrogels is an important task to find valuable biological resources for human welfare. The conventional microfluidic designs are mainly targeted only for highly dispersed spherical bioparticles. Advanced structures should be taken into consideration for handling such aggregated and non-spherical microorganisms. Here, to address the challenge, we propose a new type of cylindrical-shaped micropillar array in a microfluidic device for enhancing the dispersion of cell clusters and the isolation of individual cells into individual micro-hydrogels for potential practical applications. The incorporated micropillars act as a sieve for the breaking of Escherichia coli (E. coli) clusters into single cells in a polymer mixture. Furthermore, the combination of hydrodynamic forces and a flow-focusing technique will improve the probability of encapsulation of a single cell into each hydrogel with a broad range of cell concentrations. This proposed strategy and device would be a useful platform for genetically modified microorganisms for practical applications.

  10. Reentrant behaviour in polyvinyl alcohol-borax hydrogels

    Science.gov (United States)

    Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

    2018-01-01

    Polyvinyl alcohol (PVA) hydrogels, cross-linked with varying concentrations of borax, were studied with small angle neutron scattering (SANS), x-ray diffraction (XRD) and differential thermal analysis (DTA). The SANS data satisfy the Ornstein-Zernike approximation. The hydrogels are modelled as PVA chains bound by borate cross-links. Water occupies the spaces within the three-dimensional hydrogel network. The mesh size ξ indicates reentrant behaviour i.e. at first, ξ increases and later decreases as a function of borax concentration. The behaviour is explained on the basis of the balance between the charged di-diol cross-links and the shielding by free ions in the solvent. XRD and DTA show the molecular size of water in the solvent and the glass transition temperature commensurate with reentrant behaviour.

  11. Synthesis and Characterization of Super absorbent Hydrogels Based on Natural Polymers Using Ionizing Radiations

    International Nuclear Information System (INIS)

    Deghiedy, N.M.A.

    2010-01-01

    Radiation processing technology is a useful tool for modification of polymer material including grafting of monomer onto polymer. In this study, novel super absorbent hydrogels was prepared with biodegradable and eco-friendly properties by graft copolymerization of chitosan and different synthetic monomers (AAc, DEAEMA, HEMA, HPMA and HEA) using gamma irradiation to examine the potential use of these hydrogels in the controlled drug release systems. The different chitosan hydrogels were characterized using FTIR spectroscopy, scanning electron microscopy and thermal analysis techniques. The effects of the preparation conditions on the gelation process of the synthesized copolymer were investigated. The influence of variables such as feed concentration, irradiation dose, composition ratio, ph and temperature on the swelling of the prepared hydrogels was also examined. The water absorbency of these hydrogels in various ph and salt solutions was studied. The swelling kinetics of the prepared hydrogels and in vitro release dynamics of model drug (Chlortetracycline hydrochloride) from these hydrogels has been studied for the evaluation of swelling mechanism and drug release mechanism from the hydrogels. The adsorption and in vitro release profiles of Chlortetracycline HCl from the prepared gels were also estimated in different ph buffers. The amount of drug released from CS/ (AAc-DEAEMA) hydrogels was higher than that released from other modified CS/AAc hydrogels. This preliminary investigation of chitosan based hydrogels showed that they may be exploited to expand the utilization of these systems in drug delivery applications

  12. 5-FU-hydrogel inhibits colorectal peritoneal carcinomatosis and tumor growth in mice

    International Nuclear Information System (INIS)

    Wang, Yongsheng; Gong, Changyang; Yang, Li; Wu, Qinjie; Shi, Shuai; Shi, Huashan; Qian, Zhiyong; Wei, Yuquan

    2010-01-01

    Colorectal peritoneal carcinomatosis (CRPC) is a common form of systemic metastasis of intra-abdominal cancers. Intraperitoneal chemotherapy is a preferable option for colorectal cancer. Here we reported that a new system, 5-FU-loaded hydrogel system, can improve the therapeutic effects of intraperitoneal chemotherapy. A biodegradable PEG-PCL-PEG (PECE) triblock copolymer was successfully synthesized. The biodegradable and temperature sensitive hydrogel was developed to load 5-FU. Methylene blue-loaded hydrogel were also developed for visible observation of the drug release. The effects and toxicity of the 5-FU-hydrogel system were evaluated in a murine CRPC model. The hydrogel system is an injectable flowing solution at ambient temperature and forms a non-flowing gel depot at physiological temperature. 5-FU-hydrogel was subsequently injected into abdominal cavity in mice with CT26 cancer cells peritoneal dissemination. The results showed that the hydrogel delivery system prolonged the release of methylene blue; the 5-FU-hydrogel significantly inhibited the peritoneal dissemination and growth of CT26 cells. Furthermore, intraperitoneal administration of the 5-FU-hydrogel was well tolerated and showed less hematologic toxicity. Our data indicate that the 5-FU-hydrogel system can be considered as a new strategy for peritoneal carcinomatosis, and the hydrogel may provide a potential delivery system to load different chemotherapeutic drugs for peritoneal carcinomatosis of cancers