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Sample records for 2-hydroxyethyl methacrylate hema

  1. Preliminary dose response study of a gel dosimeter using 2-Hydroxyethyl Methacrylate (HEMA).

    PubMed

    Trapp, J V; Leach, M O; Webb, S

    2005-09-01

    In this work we present a gel dosimeter based on 2-Hydroxyethyl Methacrylate (HEMA). The gel dosimeter is manufactured in normal atmospheric oxygen (normoxic) and undergoes a measurable change after irradiation. The gel is shown to provide a signal to noise ratio of up to at least 35 and have a linear change in transverse relaxation rate up to 70 Gy when measured with magnetic resonance imaging.

  2. Cell toxicity of 2-hydroxyethyl methacrylate (HEMA): the role of oxidative stress.

    PubMed

    Morisbak, Else; Ansteinsson, Vibeke; Samuelsen, Jan T

    2015-08-01

    2-Hydroxyethyl methacrylate (HEMA) is a methacrylate monomer used in polymer-based dental-restorative materials. In this study, the viability of human lung epithelial cells, BEAS-2B, was investigated after exposure to this monomer. Exposure to HEMA reduced the viability of the BEAS-2B cells as a result of increased apoptosis, interruption of the cell cycle, and decreased cell proliferation. Depletion of cellular glutathione and increased levels of reactive oxygen species (ROS) were seen after exposure of BEAS-2B cells to HEMA. The glutathione synthase inhibitor, L-buthioninesulfoximine (BSO), was used to study whether the reduced viability was caused by glutathione depletion and increased levels of ROS. Similarly to incubation with HEMA, incubation with BSO resulted in glutathione depletion and increased ROS levels, without increasing cell death or inhibiting cell growth. The results indicate that HEMA-induced cell damage is not caused exclusively by these mechanisms. Mechanisms other than glutathione depletion and ROS formation seem to be of importance for the toxic effect of HEMA on lung epithelial cells.

  3. Optical absorption intensities of trivalent erbium in a 2-hydroxyethyl methacrylate (HEMA) polymeric host

    NASA Astrophysics Data System (ADS)

    Sardar, Dhiraj K.; Yow, Raylon M.; Gruber, John B.

    2008-02-01

    The standard Judd-Ofelt model has been applied to the room temperature absorption intensities of Er 3+(4f 11) transitions in a plastic host 2-hydroxyethyl methacrylate, referred to as HEMA, to determine the three phenomenological intensity parameters: Ω2, Ω4, and Ω6. Values are used to determine the spectroscopic quality factor for Er 3+ in HEMA and are compared to those for Er 3+ in crystalline hosts. The intensity parameters are subsequently used to determine the radiative decay rates and branching ratios of the Er 3+ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds 2 S+1 L J of Er 3+(4f 11) in HEMA. Using the radiative decay rates for Er 3+(4f 11) transitions between the corresponding excited states and the lower-lying states, the radiative lifetimes of eight excited states are determined.

  4. Resin monomer 2-hydroxyethyl methacrylate (HEMA) is a potent inducer of apoptotic cell death in human and mouse cells.

    PubMed

    Paranjpe, A; Bordador, L C F; Wang, M-Y; Hume, W R; Jewett, A

    2005-02-01

    Mechanisms by which the resin monomer 2-hydroxyethyl methacrylate (HEMA) induces hypersensitivity reactions in humans are not well-established, nor have the direct effects of HEMA on cell death been fully characterized. The objective of this study was to establish whether HEMA is capable of inducing apoptotic cell death, and whether differences exist in the levels of apoptotic death induced by HEMA in cells obtained from healthy individuals and from patients with established HEMA hypersensitivity. HEMA induced apoptotic death in Peripheral Blood Mononuclear Cells (PBMCs) obtained from both healthy and HEMA-sensitized patients and in the murine RAW cells in a dose-dependent manner. However, induction of cell death by HEMA was lower in PBMCs obtained from patients in comparison with healthy individuals. Studies reported in this paper demonstrate that HEMA induces apoptotic death, and that decreased susceptibility of lymphocytes to HEMA-mediated death might be an important mechanism for the generation and persistence of hypersensitivity reactions in patients.

  5. A study of normoxic polymer gel using monomer 2-hydroxyethyl methacrylate (HEMA)

    NASA Astrophysics Data System (ADS)

    Ishak, Siti Atiqah; Mustafa, Iskandar Shahrim; Rahman, Azhar Abdul; Moktar, Mohd; Min, Ung Ngie

    2015-04-01

    The aim of this study is to determine the sensitivity of HEMA-polymer gel mixture consist of monomer 2-hydroxyethyl methacrylate (HEMA) with different types of composition. Several composition of HEMA-polymer gel were fabricated and the gels were irradiated with radiation dose between 10 cGy to 100cGy by using x-ray machine and 100 cGy to 1400 cGy by using 6 MV photon beam energy of linear accelerator. The degree of polymerization was evaluated by using magnetic resonance imaging (MRI) with dependence of R2-dose response. Polymer gel consists of cross-linker, anti-oxidant Tetrakis(Hydroxymethyl)phosphonium chloride solution (THPC) and oxygen scavenger hydroquinone shows a stable sensitivity with highest dose dependency. Besides, the results shows the stage polymerization consist of induction, propagation, termination, and chain transfer were dependence with type of chemical mixture and radiation dose. Thus, normoxic HEMA-polymer gel with the different gel formulations can have a better dose resolution and an appropriate recipe must be selected to increase of the sensitivity required and the stability of the dosimeter.

  6. A study of normoxic polymer gel using monomer 2-hydroxyethyl methacrylate (HEMA)

    SciTech Connect

    Ishak, Siti Atiqah; Mustafa, Iskandar Shahrim; Rahman, Azhar Abdul; Moktar, Mohd; Min, Ung Ngie

    2015-04-24

    The aim of this study is to determine the sensitivity of HEMA-polymer gel mixture consist of monomer 2-hydroxyethyl methacrylate (HEMA) with different types of composition. Several composition of HEMA-polymer gel were fabricated and the gels were irradiated with radiation dose between 10 cGy to 100cGy by using x-ray machine and 100 cGy to 1400 cGy by using 6 MV photon beam energy of linear accelerator. The degree of polymerization was evaluated by using magnetic resonance imaging (MRI) with dependence of R2-dose response. Polymer gel consists of cross-linker, anti-oxidant Tetrakis(Hydroxymethyl)phosphonium chloride solution (THPC) and oxygen scavenger hydroquinone shows a stable sensitivity with highest dose dependency. Besides, the results shows the stage polymerization consist of induction, propagation, termination, and chain transfer were dependence with type of chemical mixture and radiation dose. Thus, normoxic HEMA-polymer gel with the different gel formulations can have a better dose resolution and an appropriate recipe must be selected to increase of the sensitivity required and the stability of the dosimeter.

  7. 2-Hydroxyethyl methacrylate (HEMA) promotes IgG but not IgM antibody production in vivo in mice.

    PubMed

    Andersson, Jennie; Dahlgren, Ulf

    2011-08-01

    Individuals working in a dental clinic are exposed to 2-hydroxyethyl methacrylate (HEMA). HEMA has been found to have several effects on the immune system, including acting as an adjuvant in mice and stimulating the production of human IgG1 in vitro. In this study we continued to explore the immunomodulatory properties of HEMA in mice. Mice were co-injected subcutaneously with the following: HEMA + ovalbumin (OVA) in bicarbonate buffer, OVA in bicarbonate buffer, HEMA in bicarbonate buffer, or bicarbonate buffer alone. Mice immunized with OVA were killed 2 wk after a booster injection. Mice exposed to HEMA only were killed 6 d after the last injection with HEMA. Serum and spleens were collected. The activities of anti-OVA IgG and anti-OVA IgM were determined using ELISAs, as was the in vitro production of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) by splenocytes after 2 d of incubation. Splenocyte proliferation was analyzed using [(3) H]thymidine decomposition. Mice exposed twice to HEMA in vivo had a higher baseline and a higher concanavalin A-stimulated proliferation of splenocytes, and produced less TNF-α in relation to IL-6, compared with controls. Immunization of mice with OVA/HEMA resulted in a higher anti-OVA IgG activity, relative to anti-OVA IgM activity, compared with controls. In conclusion, HEMA has selective effects on cytokine and antibody production in mice.

  8. Effect of 2-hydroxyethyl-methacrylate (HEMA) on the phagocytic and respiratory burst activity of human neutrophils and monocytes.

    PubMed

    Andersson, Jennie; Dahlgren, Ulf I

    2008-08-01

    Neutrophils and monocytes/macrophages (MØ), found in oral mucosa and gingival sulcus, phagocytose and kill bacteria using products produced during a respiratory burst. 2-Hydroxyethyl-methacrylate (HEMA) is a major component released from resin glass ionomer and dental adhesives. Hence, in pulp and gingiva, phagocytes can come into contact with unpolymerized HEMA monomers. The aim of this study was to examine the effects of exposure to HEMA on neutrophil and monocyte bactericidal function. Blood collected from five female volunteers was exposed in vitro to HEMA for 2 h and then phagocytosis, respiratory burst, and cellular integrity were measured using flow cytometry. Respiratory burst was quantified by measuring fluorescent rhodamine 123 generated via oxidation of dihydrorhodamine 123. Cellular membrane integrity was evaluated by staining with propidium iodide. The respiratory burst activity of the neutrophils was significantly decreased by exposure to 7.5 and 15 mM HEMA. No significant effect of HEMA was seen on the number of granulocytes or monocytes capable of performing respiratory burst. Furthermore, there was no significant effect of HEMA on the phagocytic activity of the monocytes or the granulocytes. In conclusion, HEMA did not affect the phagocytosis activity of neutrophils; however, the ability of the cells to kill internalized prey was significantly reduced.

  9. DNA-damage, cell-cycle arrest and apoptosis induced in BEAS-2B cells by 2-hydroxyethyl methacrylate (HEMA).

    PubMed

    Ansteinsson, V; Solhaug, A; Samuelsen, J T; Holme, J A; Dahl, J E

    2011-08-16

    The methacrylate monomer 2-hydroxyethyl methacrylate (HEMA) is commonly used in resin-based dental restorative materials. These materials are cured in situ and HEMA and other monomers have been identified in ambient air during dental surgery. In vitro studies have demonstrated a toxic potential of methacrylates, and concerns have been raised regarding possible health effects due to inhalation. In this study we have investigated the mechanisms of HEMA-induced toxicity in the human lung epithelial cell line BEAS-2B. Depletion of cellular glutathione (GSH) and an increased level of reactive oxygen species (ROS) were seen after 2h of exposure, but the levels were restored to control levels after 12h. After 24h, inhibited cell proliferation and apoptotic cell death were found. The results of the Comet assay and the observed phosphorylation of DNA-damage-associated signalling proteins including Chk2, H2AX, and p53 suggest that the toxicity of HEMA is mediated by DNA damage. Further, the antioxidant trolox did not counteract the HEMA-induced cell-cycle arrest, which indicates that the DNA damage is of non-oxidative origin.

  10. Experimental study of albumin and lysozyme adsorption onto acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) surfaces.

    PubMed

    Moradi, Omid; Modarress, Hamid; Noroozi, Mehdi

    2004-03-01

    Many commercial soft contact lenses are based on poly-2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) hydrogels. The adsorption of proteins, albumin and lysozyme, on such contact lens surfaces may cause problems in their applications. In this work the adsorption of proteins, albumin and lysozyme, on hydrogel surfaces, AA and HEMA, was investigated as a function of concentration of protein. Also the effects of pH and ionic strength of protein solution on the adsorption of protein were examined. The obtained results indicated that the degree of adsorption of protein increased with the concentration of protein, and the adsorption of albumin on HEMA surface at the studied pHs (6.2-8.6) was higher than AA surface, whereas the adsorption of lysozyme on AA surface at the same pHs was higher than HEMA. The change in ionic strength of protein solution affected the proteins adsorption on both AA and HEMA surfaces. Also, the amount of sodium ions deposited on the AA surface was much higher than HEMA surface. This effect can be related to the negative surface charge of AA and its higher tendency for adsorption of sodium ions compared to the HEMA surface.

  11. The influence of glutathione on redox regulation by antioxidant proteins and apoptosis in macrophages exposed to 2-hydroxyethyl methacrylate (HEMA).

    PubMed

    Krifka, Stephanie; Hiller, Karl-Anton; Spagnuolo, Gianrico; Jewett, Anahid; Schmalz, Gottfried; Schweikl, Helmut

    2012-07-01

    Resin monomers like 2-hydroxyethyl methacrylate (HEMA) disturb cell functions including responses of the innate immune system, mineralization and differentiation, or induce cell death via apoptosis. These phenomena are associated with oxidative stress and a reduction in the concentration of the antioxidant glutathione (GSH), resulting in imbalanced redox homeostasis. Thus far, the precise mechanism of how resin monomers interfere with cellular redox regulation is unknown. The present study provides insight into the induction of apoptosis and the differential expression of antioxidant enzymes depending on the availability of GSH. Buthionine sulfoximine (BSO) was used to inhibit GSH synthesis, while 2-oxothiazolidine-4-carboxylate (OTC), and N-acetylcysteine (NAC) as prodrugs supported GSH synthesis in RAW264.7 mouse macrophages exposed to HEMA (0-8 mm) for 24 h. The level of GSH was significantly decreased after cells were preincubated with BSO, and the formation of reactive oxygen species (ROS) increased in cultures subsequently exposed to HEMA. Apoptosis was drastically increased by BSO in HEMA-exposed cell cultures as well, but OTC and NAC retracted HEMA-induced cell death. These results show that dental monomer-induced apoptosis is causally related to the availability of GSH. The hydrogen peroxide decomposing enzymes glutathione peroxidase (GPx1/2) and catalase were differentially regulated in HEMA-exposed cultures. Expression of GPx1/2 was inhibited by HEMA and further reduced in the presence of BSO. SOD1 (superoxide dismutase) expression was inhibited in the presence of HEMA, and was decreased to an even greater extent by BSO, possibly due to H(2)O(2)-feedback inhibition. The expression of catalase was considerably up-regulated in HEMA-exposed cultures, implying that H(2)O(2) is the type of ROS that is significantly increased in monomer-exposed cells. OTC and NAC counteracted the effect of HEMA on GPx1/2, SOD1, and catalase expression. HO-1 (heme oxygenase

  12. Swelling equilibria for cationic 2-hydroxyethyl methacrylate (HEMA)-based hydrogels

    SciTech Connect

    Baker, J.P.; Blanch, H.W.; Prausnitz, J.M.

    1993-08-01

    Cationic HEMA-based hydrogels were synthesized by copolymerizing HEMA with [(methacrylamido)propyl]trimethylammonium chloride (MAPTAC). Swelling equilibria were measured in pure water an in aqueous sodium chloride solutions. Hydrogel swelling is an increasing function of the MAPTAC content. A Flory-type swelling model using a concentration-dependent Flory {Chi} parameter semi-qualitatively describes poly(HEMA co-MAPTAC) hydrogel swelling in aqueous sodium chloride.

  13. Study of polymeric interactions of copolymers: 2-hydroxyethyl methacrylate (HEMA) and 2,3-dihydroxypropyl methacrylate (DHPMA) with copper hydroxylated nanoballs.

    PubMed

    McCann, Krystal; Knudsen, Bernard; Ananthoji, Ramakanth; Perry, John J; Hilker, Brent; Zaworotko, Michael J; Harmon, Julie P

    2010-09-01

    2-hydroxyethyl methacrylate (HEMA) and 2,3-dihydroxypropyl methacrylate (DHPMA) were used to synthesize novel nanocomposites containing 0.5% by weight of copper hydroxylated nanoballs. Glass transition temperatures of the copolymers and their respective nanocomposites were determined by using differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) was employed to measure the degradation temperatures of the samples and to determine if the degradation is a single step process or multiple step process. The dielectric permittivity (epsilon') and loss factor (epsilon") were measured via Dielectric Analysis (DEA) in the frequency range 0.1 Hz to 100 kHz and between the temperature -150 to 190 degrees C. gamma, beta, and alphabeta conductivity relaxations were revealed using the electric modulus formalism. The activation energies for the relaxations were calculated. Argand plots of M" versus M' were used to study the viscoelastic effects of both copolymer and the composites. Herein we show that it is possible to tune solubility and relaxation properties which are important to the design of new biomaterials.

  14. Synergistic effect on corrosion resistance of Phynox substrates grafted with surface-initiated ATRP (co)polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-hydroxyethyl methacrylate (HEMA).

    PubMed

    Barthélémy, Bastien; Maheux, Simon; Devillers, Sébastien; Kanoufi, Frédéric; Combellas, Catherine; Delhalle, Joseph; Mekhalif, Zineb

    2014-07-09

    Phynox is of high interest for biomedical applications due to its biocompatibility and corrosion resistance. However, some Phynox applications require specific surface properties. These can be imparted with suitable surface functionalizations of its oxide layer. The present work investigates the surface-initiated atom transfer radical polymerization (ATRP) of 2-methacryloyoxyethyl phosphorylcholine (MPC), 2-hydroxyethyl methacrylate (HEMA), and ATRP copolymerization of (HEMA-co-MPC) (block and statistic copolymerization with different molar ratios) on grafted Phynox substrates modified with 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid (BUPA) as initiator. It is found that ATRP (co)polymerization of these monomers is feasible and forms hydrophilic layers, while improving the corrosion resistance of the system.

  15. Genotoxicity and cytotoxicity of 2-hydroxyethyl methacrylate.

    PubMed

    Pawlowska, Elzbieta; Poplawski, Tomasz; Ksiazek, Dominika; Szczepanska, Joanna; Blasiak, Janusz

    2010-02-01

    Resin-based methacrylate materials are widely used in restorative dentistry. They are viscous substances that are converted into solid material via polymerization. This process, however, may be incomplete, leading to the release of monomers into the oral cavity and the pulp, which can be reached through the dentin micro-channels. This opens the opportunity for the monomers to reach the bloodstream. Monomers can reach concentrations in the millimolar range, high enough to cause cellular damage, so it is justified to study their potential toxic effects. In the present work we investigated the cytotoxicity and genotoxicity of 2-hydroxyethyl methacrylate (HEMA) in human peripheral blood lymphocytes and A549 lung-tumour cells. HEMA at concentrations up to 10mM neither affected the viability of the cells nor interacted with isolated plasmid DNA during a 1h exposure. However, HEMA induced concentration-dependent DNA damage in lymphocytes, as assessed by alkaline and pH 12.1 versions of the comet assay. HEMA did not cause double-strand breaks, as assessed by the neutral version of the comet assay and pulsed-field gel electrophoresis. The use of DNA repair enzymes, spin traps and vitamin C produced results suggesting that HEMA induced oxidative modifications to DNA bases. DNA damage caused by HEMA at 10mM was removed within 120min. HEMA induced apoptosis in a concentration-dependent manner and caused cell-cycle delay at the G0/G1-checkpoint. Methylglycol chitosan displayed a protective effect against the DNA-damaging action of HEMA. The results obtained in this study suggest that HEMA induces adverse biological effects, mainly via reactive oxygen species, which can lead to DNA damage, apoptosis and cell-cycle delay. Chitosan and its derivatives can be considered as additional components of dental restoration to decrease the harmful potency of HEMA.

  16. Biocompatible Bacterial Cellulose-Poly(2-hydroxyethyl methacrylate) Nanocomposite Films

    PubMed Central

    Figueiredo, Andrea G. P. R.; Figueiredo, Ana R. P.; Alonso-Varona, Ana; Fernandes, Susana C. M.; Palomares, Teodoro; Rubio-Azpeitia, Eva; Barros-Timmons, Ana; Silvestre, Armando J. D.; Pascoal Neto, Carlos; Freire, Carmen S. R.

    2013-01-01

    A series of bacterial cellulose-poly(2-hydroxyethyl methacrylate) nanocomposite films was prepared by in situ radical polymerization of 2-hydroxyethyl methacrylate (HEMA), using variable amounts of poly(ethylene glycol) diacrylate (PEGDA) as cross-linker. Thin films were obtained, and their physical, chemical, thermal, and mechanical properties were evaluated. The films showed improved translucency compared to BC and enhanced thermal stability and mechanical performance when compared to poly(2-hydroxyethyl methacrylate) (PHEMA). Finally, BC/PHEMA nanocomposites proved to be nontoxic to human adipose-derived mesenchymal stem cells (ADSCs) and thus are pointed as potential dry dressings for biomedical applications. PMID:24093101

  17. Biocompatible bacterial cellulose-poly(2-hydroxyethyl methacrylate) nanocomposite films.

    PubMed

    Figueiredo, Andrea G P R; Figueiredo, Ana R P; Alonso-Varona, Ana; Fernandes, Susana C M; Palomares, Teodoro; Rubio-Azpeitia, Eva; Barros-Timmons, Ana; Silvestre, Armando J D; Pascoal Neto, Carlos; Freire, Carmen S R

    2013-01-01

    A series of bacterial cellulose-poly(2-hydroxyethyl methacrylate) nanocomposite films was prepared by in situ radical polymerization of 2-hydroxyethyl methacrylate (HEMA), using variable amounts of poly(ethylene glycol) diacrylate (PEGDA) as cross-linker. Thin films were obtained, and their physical, chemical, thermal, and mechanical properties were evaluated. The films showed improved translucency compared to BC and enhanced thermal stability and mechanical performance when compared to poly(2-hydroxyethyl methacrylate) (PHEMA). Finally, BC/PHEMA nanocomposites proved to be nontoxic to human adipose-derived mesenchymal stem cells (ADSCs) and thus are pointed as potential dry dressings for biomedical applications.

  18. Dual-functional electrospun poly(2-hydroxyethyl methacrylate).

    PubMed

    Zhang, Bo; Lalani, Reza; Cheng, Fang; Liu, Qingsheng; Liu, Lingyun

    2011-12-01

    Poly(2-hydroxyethyl methacrylate) (pHEMA) has been widely used in many biomedical applications due to its well-known biocompatibility. For tissue engineering applications, porous scaffolds that mimic fibrous structures of natural extracellular matrix and possess high surface-area-to-volume ratios are highly desirable. So far, a systematic approach to control diameter and morphology of pHEMA fibers has not been reported and potential applications of pHEMA fibers have barely been explored. In this work, pHEMA was synthesized and processed into fibrous scaffolds using an electrospinning approach. Fiber diameters from 270 nm to 3.6 μm were achieved by controlling polymer solution concentration and electrospinning flow rate. Post-electrospinning thermal treatment significantly improves integrity of the electrospun membranes in water. The pHEMA microfibrous membranes exhibited water absorption up to 280% (w/w), whereas the pHEMA hydrogel only absorbed 70% water. Fibrinogen adsorption experiments demonstrate that the electrospun pHEMA fibers highly resist nonspecific protein adsorption. Hydroxyl groups on electrospun pHEMA fibers were further activated for protein immobilization. A bovine serum albumin (BSA) binding capacity as high as 120 mg BSA/g membrane was realized at an intermediate fiber diameter. The pHEMA fibrous scaffolds functionalized with collagen I significantly promoted fibroblast adhesion, spreading, and proliferation. We conclude that the electrospun pHEMA fibers are dual functional, that is, they resist nonspecific protein adsorption meanwhile abundant hydroxyl groups on fibers allow effective conjugation of biomolecules in a nonfouling background. High water absorption and dual functionality of the electrospun pHEMA fibers may lead to a number of potential applications such as wound dressings, tissue scaffolds, and affinity membranes.

  19. The toxicokinetics and distribution of 2-hydroxyethyl methacrylate in mice.

    PubMed

    Durner, J; Kreppel, H; Zaspel, J; Schweikl, H; Hickel, R; Reichl, Franz X

    2009-04-01

    The cytotoxicity of dental composites has been attributed to the release of residual monomers from polymerized resin-based composites due to the degradation processes or the incomplete polymerisation of materials. 2-Hydroxyethyl methacrylate (HEMA) is one of the major components released from dental resin-based composites. It was shown in vitro that HEMA was released into the adjacent biophase from such materials during the first days after placement. In this study uptake, distribution, and excretion of 14C-HEMA applied via gastric tube or subcutaneous administration at dose levels well above those encountered in dental care were examined in mice to test the hypothesis that HEMA can reach cytotoxic levels in mammalian tissues. 14C-HEMA was taken up rapidly from the stomach and intestines after gastric administration and was widely distributed in the body following administration by each route. Most 14C was excreted within one day as (14)CO(2). Two metabolic pathways of 14C-HEMA can be described. The peak HEMA levels in all tissues examined after 24h were lower than known toxic levels. Therefore the study did not support the hypothesis.

  20. Solute solvent interaction in methyl methacrylate and 2-hydroxyethyl methacrylate monomers solutions

    NASA Astrophysics Data System (ADS)

    Al-ghamdi, Attieh A.; Bahattab, M. A.; Farhoud, M.; Al-Dossary, Mishal; Al-Enizi, Abdullah; Al-Deyab, S. S.

    2006-11-01

    Solute-solvent interactions are studied using induced birefringence measurements in monomers solutions of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), dissolved in ethanol, acetone, ethyl acetate, tetrahydrofuran and dimethyl sulfoxide, over a broad range of concentrations. The data are combined with refractive index and density to calculate the electric, optical and molar Kerr constants. All related microscopic parameters concerning the molecular structure such as nonlinear Kerr constants, anisotropic factors, and optical anisotropy have been calculated.

  1. 2-hydroxyethyl methacrylate as an inhibitor of matrix metalloproteinase-2.

    PubMed

    Carvalho, Rodrigo V; Ogliari, Fabrício A; de Souza, Ana P; Silva, Adriana F; Petzhold, Cesar L; Line, Sergio R P; Piva, Evandro; Etges, Adriana

    2009-02-01

    This study evaluated the effect of different concentrations of 2-hydroxyethyl methacrylate (HEMA) on the inhibition of matrix metalloproteinase-2 (MMP-2) in vitro. Mouse gingival explants were cultured overnight in Dulbecco's modified Eagle's minimal essential medium, following which the expression of secreted enzymes was analyzed by gelatin zymography and the effects of different amounts of HEMA on enzyme activity were investigated. The gelatinolytic proteinases present in the conditioned media were characterized as being matrix metalloproteinases (MMPs) by means of specific chemical inhibition. The MMPs present in the conditioned media were identified, using immunoprecipitation, as MMP-2. Three major bands were detected in the zymographic assays and were characterized, according to their respective molecular weights, into the following forms of MMP-2: zymogene (72 kDa), intermediate (66 kDa), and active (62 kDa). All forms of MMP-2 were inhibited by HEMA in a dose-dependent manner, implying that MMP-2 may be inhibited by HEMA in vivo.

  2. Cholesterol-modified superporous poly(2-hydroxyethyl methacrylate) scaffolds for tissue engineering.

    PubMed

    Kubinová, Sárka; Horák, Daniel; Syková, Eva

    2009-09-01

    Modifications of poly(2-hydroxyethyl methacrylate) (PHEMA) with cholesterol and laminin have been developed to design scaffolds that promote cell-surface interaction. Cholesterol-modified superporous PHEMA scaffolds have been prepared by the bulk radical copolymerization of 2-hydroxyethyl methacrylate (HEMA), cholesterol methacrylate (CHLMA) and the cross-linking agent ethylene dimethacrylate (EDMA) in the presence of ammonium oxalate crystals to introduce interconnected superpores in the matrix. With the aim of immobilizing laminin (LN), carboxyl groups were also introduced to the scaffold by the copolymerization of the above monomers with 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA). Subsequently, the MCMEMA moiety in the resulting hydrogel was hydrolyzed to [2-(methacryloyloxy)ethoxy]acetic acid (MOEAA), and laminin was immobilized via carbodiimide and N-hydroxysulfosuccinimide chemistry. The attachment, viability and morphology of mesenchymal stem cells (MSCs) were evaluated on both nonporous and superporous laminin-modified as well as laminin-unmodified PHEMA and poly(2-hydroxyethyl methacrylate-co-cholesterol methacrylate) P(HEMA-CHLMA) hydrogels. Neat PHEMA and laminin-modified PHEMA (LN-PHEMA) scaffolds facilitated MSC attachment, but did not support cell spreading and proliferation; the viability of the attached cells decreased with time of cultivation. In contrast, MSCs spread and proliferated on P(HEMA-CHLMA) and LN-P(HEMA-CHLMA) hydrogels.

  3. On permeability of methyl methacrylate, 2-hydroxyethyl methacrylate and triethyleneglycol dimethacrylate through protective gloves in dentistry.

    PubMed

    Andreasson, Harriet; Boman, Anders; Johnsson, Stina; Karlsson, Stig; Barregård, Lars

    2003-12-01

    Continuous glove use is more common in dentistry than in most other occupations, and the glove should offer protection against blood-borne infections, skin irritants and contact allergens. Methacrylate monomers are potent contact allergens, and it is known that these substances may penetrate the glove materials commonly used. The aim of this study was to assess the permeability of various types of gloves to methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and triethyleneglycol dimethacrylate (TEGDMA) with special reference to combinations with ethanol or acetone. The permeation rate and time lag breakthrough (lag-BT) for MMA (neat, or diluted to 30% in ethanol or acetone), HEMA (30% in water, ethanol, or acetone) and TEGDMA (30% in ethanol or acetone) were investigated for different protective gloves. Nine different types of gloves were tested for one or several of these methacrylates. The lag-BT for neat MMA was HEMA and TEGDMA, the lag-BTs were generally longer than for MMA. A neoprene glove seemed to be the best choice for protection against penetration of HEMA and TEGDMA. The decision on which types of gloves to use should also take into account the risks of latex allergy and contact allergy to rubber chemicals and the convenience of the gloves for fine manual work.

  4. Fabrication of carbohydrate microarrays on a poly(2-hydroxyethyl methacrylate)-based photoactive substrate.

    PubMed

    Sundhoro, Madanodaya; Wang, Hui; Boiko, Scott T; Chen, Xuan; Jayawardena, H Surangi N; Park, JaeHyeung; Yan, Mingdi

    2016-01-21

    We report the fabrication of carbohydrate microarrays on a photoactive polymer, poly(HEMA-co-HEMA-PFPA), synthesized by RAFT copolymerization of 2-hydroxyethyl methacrylate (HEMA) and perfluorophenyl azide (PFPA)-derivatized HEMA (HEMA-PFPA). PFPA allows the covalent immobilization of carbohydrates whereas the HEMA polymer provides an antifouling surface, thus the microarrays can be used directly without pretreating the array with a blocking agent. The microarrays were prepared by spin-coating the polymer followed by printing the carbohydrates. Subsequent irradiation simultaneously immobilized the carbohydrates and crosslinked the polymer matrix. The obtained 3D carbohydrate microarrays showed enhanced fluorescence signals upon treating with a fluorescent lectin in comparison with a 2D microarray. The signals were acquired at a lower lectin concentration and a shorter incubation time. When treated with E. coli bacteria, the carbohydrate microarray showed results that were consistent with their binding patterns.

  5. N-acetyl cysteine directed detoxification of 2-hydroxyethyl methacrylate by adduct formation.

    PubMed

    Nocca, Giuseppina; D'Antò, Vincenzo; Desiderio, Claudia; Rossetti, Diana Valeria; Valletta, Rosa; Baquala, Adriana Marquez; Schweikl, Helmut; Lupi, Alessandro; Rengo, Sandro; Spagnuolo, Gianrico

    2010-03-01

    Cytotoxicity of the dental resin monomer 2-hydroxyethyl methacrylate (HEMA) and the protective effects of N-acetyl cysteine (NAC) on monomer-induced cell damage are well demonstrated. The aim of our study was to analyze the hypothesis that the protection of NAC from HEMA cytotoxicity might be due to direct NAC adduct formation. To this end, using HPLC we first measured the actual intracellular HEMA concentrations able to cause toxic effects on 3T3-fibroblasts and then determined the decrease in intracellular and extracellular HEMA levels in the presence of NAC. In addition, by capillary electrophoresis coupled with mass spectrometry analysis (CE-MS), we evaluated NAC-HEMA adduct formation. HEMA reduced 3T3 cell vitality in a dose- and time-dependent manner. The concentration of HEMA inside the cells was 15-20 times lower than that added to the culture medium for cell treatment (0-8 mmol/L). In the presence of 10 mmol/L NAC, both intracellular and extracellular HEMA concentrations greatly decreased in conjunction with cytotoxicity. NAC-HEMA adducts were detected both in the presence and absence of cells. Our findings suggest that the in vitro detoxification ability of NAC against HEMA-induced cell damage occurs through NAC adduct formation. Moreover, we provide evidence that the actual intracellular concentration of HEMA able to cause cytotoxic effects is at least one magnitude lower than that applied extracellularly.

  6. Thermal behavior of poly(2-hydroxyethyl methacrylate-bis-[trimethoxysilylpropyl]amine) networks

    NASA Astrophysics Data System (ADS)

    Bustos Figueroa, L. A.; Salgado Delgado, R.; García Hernandez, E.; Vargas Galarza, Z.; Rubio Rosas, E.; Salgado Rodriguez, R.

    2013-06-01

    Poly(HEMA-BisSi) networks were prepared by using acid-catalyzed sol-gel of bis-[trimethoxysilylpropyl]amine (BisSi) and free radical polymerization of 2-hydroxyethyl methacrylate (HEMA). The thermal properties of the poly(HEMA-BisSi) networks were investigated with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermal behavior of these networks was also compared with homopolymers (The networks formed in both PHEMA and PBisSi gels were identified). The glass transition temperature (Tg) of PHEMA homopolymer was found as 103.74 °C. The thermal degradation of the poly(HEMA-BisSi) networks with different silica contents (e.g. 10, 15 and 25 wt%) were evaluated with use of DTG. It was observed that the thermal degradation temperature of poly(HEMA-BisSi) networks changed much with the BisSi content.

  7. Non-fouling hydrogels of 2-hydroxyethyl methacrylate and zwitterionic carboxybetaine (meth)acrylamides.

    PubMed

    Kostina, Nina Yu; Rodriguez-Emmenegger, Cesar; Houska, Milan; Brynda, Eduard; Michálek, Jiří

    2012-12-10

    Five poly(betaine) brushes were prepared, and their resistance to blood plasma fouling was studied. Two carboxybetaines monomers were copolymerized with 2-hydroxyethyl methacrylate (HEMA) to prepare novel hydrogels. By increasing the content of the zwitterionic comonomer, a 4-fold increase in the water content could be achieved while retaining mechanical properties close to the widely used poly(HEMA) hydrogels. All hydrogels showed an unprecedentedly low fouling from blood plasma. Remarkably, by copolymerization with 10 mol % of carboxybetaine acrylamide, hydrogels fully resistant to blood plasma were prepared.

  8. Solid state dye lasers based on 2-hydroxyethyl methacrylate and methyl methacrylate co-polymers

    NASA Astrophysics Data System (ADS)

    Giffin, Shirin M.; McKinnie, Iain T.; Wadsworth, William J.; Woolhouse, Anthony D.; Smith, Gerald J.; Haskell, Tim G.

    1999-03-01

    The laser performance of a range of solid state dye lasers based on rhodamine 590-doped co-polymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) has been investigated. The optimisation of preparation conditions, including polymerisation initiator and solvent for dye delivery is discussed in detail. Laser efficiency is compared for different polymeric hosts and dye concentrations with a range of output couplers, cavity lengths and repetition rates. Passive and dynamic loss have been determined for each host medium. Laser efficiencies of optimised polymers are among the highest reported for rhodamine 590-doped solid state dye lasers under these operating conditions. Highest slope efficiency of 35% and lowest threshold fluence of 0.06 J cm -2 were obtained with dimethyl sulphoxide (DMSO) additive in MPMMA at 10 Hz repetition rate.

  9. Effect of 2-hydroxyethyl methacrylate on human pulp cell survival pathways ERK and AKT.

    PubMed

    Spagnuolo, Gianrico; D'Antò, Vincenzo; Valletta, Rosa; Strisciuglio, Caterina; Schmalz, Gottfried; Schweikl, Helmut; Rengo, Sandro

    2008-06-01

    Previous investigations have revealed that dental monomers could affect intracellular pathways leading to cell survival or cell death. Mitogen-activated protein kinase (MAPK) and protein kinase B (AKT) might mediate cell responses as well as cell survival and apoptosis. The purpose of this study was to evaluate the effects of 2-hydroxyethyl methacrylate (HEMA) on the ERK1/2 and AKT pathways in human primary pulp fibroblasts (HPCs). HPCs were treated with various concentrations of HEMA, after which viability and reactive oxygen species levels were determined by flow cytometry with Annexin V-PI staining and 2,7-dichlorofluorescine diacetate, respectively. Whole-cell extracts were immunoblotted with anti-P-Akt or anti-P-ERK1/2. Cell viability decreased in a dose-dependent manner after HEMA exposure, showing a significant decrease with 10 mmol/L HEMA (p < .05). HEMA treatment resulted in a 4-fold increase in reactive oxygen species formation (p < .05). A short HEMA exposure (30-90 minutes) increased ERK1/2 phosphorylation, whereas a decrease in the AKT phosphorylation was observed. Selective inhibitors of the ERK (PD98059) and AKT (LY294002) pathways amplified HPC cell damage after HEMA exposure. Our findings demonstrated that HEMA exposure modulates the ERK and AKT pathways in different manners, and that in turn, they function in parallel to mediate pro-survival signaling in pulp cells subjected to HEMA cytotoxicity.

  10. Biotransformation enzymes and lung cell response to 2-hydroxyethyl-methacrylate.

    PubMed

    Samuelsen, J T; Holme, J A; Låg, M; Schwarze, P E; Dahl, J E; Becher, R

    2012-02-01

    The aim of this in vitro study was to investigate possible involvement of cytochrome P450 (CYP) enzymes in modifying the toxic potential of 2-hydroxyethyl-methacrylate (HEMA). Primary cultures of CYP expressing rat alveolar type 2 cells were exposed to varying concentrations of HEMA. Nuclear translocation of aryl hydrocarbon receptor (AhR) after HEMA exposure (100 μM) was demonstrated by immunocytochemical staining. Using reverse transcriptase PCR, increased mRNA level of AhR-regulated genes encoding enzymes associated with detoxification of xenobiotics were found. Exposure to 1 mM HEMA rapidly (6 h) resulted in cells with an apoptotic like morphology as suggested by marked nuclear condensation. Cotreatment of the HEMA exposed cells with a CYP inhibitor (disulfiram) or an antioxidant (vitamin C) effectively rescued the cells from this fate. Despite this effect of vitamin C, no increased level of reactive oxygen species was observed in the HEMA exposed cells. Our results suggest that HEMA activates AhR regulated gene transcription and that CYP is involved in the formation of a highly reactive HEMA metabolite.

  11. Chemically induced graft copolymerization of 2-hydroxyethyl methacrylate onto polyurethane surface for improving blood compatibility

    NASA Astrophysics Data System (ADS)

    He, Chunli; Wang, Miao; Cai, Xianmei; Huang, Xiaobo; Li, Li; Zhu, Haomiao; Shen, Jian; Yuan, Jiang

    2011-11-01

    To improve hydrophilicity and blood compatibility properties of polyurethane (PU) film, we chemically induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto the surface of polyurethane film using benzoyl peroxide as an initiator. The effects of grafting temperature, grafting time, monomer and initiator concentrations on the grafting yields were studied. The maximum grafting yield value was obtained 0.0275 g/cm2 for HEMA. Characterization of the films was carried out by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements. ATR-FTIR data showed that HEMA was successfully grafted onto the PU films surface. Water contact angle measurement demonstrated the grafted films possessed a relatively hydrophilic surface. The blood compatibility of the grafted films was preliminarily evaluated by a platelet-rich plasma adhesion test and hemolysis test. The results of platelet adhesion experiment showed that polyurethane grafted polymerization with monomer of 2-hydroxyethyl methacrylate had good blood compatibility featured by the low platelet adhesion. Hemolysis rate of the PU-g-PHEMA films was dramatically decreased than the ungrafted PU films. This kind of new biomaterials grafted with HEMA monomers might have a potential usage for biomedical applications.

  12. RGDS- and SIKVAVS-Modified Superporous Poly(2-hydroxyethyl methacrylate) Scaffolds for Tissue Engineering Applications.

    PubMed

    Macková, Hana; Plichta, Zdeněk; Proks, Vladimír; Kotelnikov, Ilya; Kučka, Jan; Hlídková, Helena; Horák, Daniel; Kubinová, Šárka; Jiráková, Klára

    2016-11-01

    Three-dimensional hydrogel supports for mesenchymal and neural stem cells (NSCs) are promising materials for tissue engineering applications such as spinal cord repair. This study involves the preparation and characterization of superporous scaffolds based on a copolymer of 2-hydroxyethyl and 2-aminoethyl methacrylate (HEMA and AEMA) crosslinked with ethylene dimethacrylate. Ammonium oxalate is chosen as a suitable porogen because it consists of needle-like crystals, allowing their parallel arrangement in the polymerization mold. The amino group of AEMA is used to immobilize RGDS and SIKVAVS peptide sequences with an N-γ-maleimidobutyryloxy succinimide ester linker. The amount of the peptide on the scaffold is determined using (125) I radiolabeled SIKVAVS. Both RGDS- and SIKVAVS-modified poly(2-hydroxyethyl methacrylate) scaffolds serve as supports for culturing human mesenchymal stem cells (MSCs) and human fetal NSCs. The RGDS sequence is found to be better for MSC and NSC proliferation and growth than SIKVAVS.

  13. Mechanisms of N-acetyl cysteine-mediated protection from 2-hydroxyethyl methacrylate-induced apoptosis.

    PubMed

    Paranjpe, Avina; Cacalano, Nicholas A; Hume, Wyatt R; Jewett, Anahid

    2008-10-01

    Resin-based materials are now commonly used in dentistry in restorative materials as well as in endodontic sealers. These materials have been shown to be cytotoxic. The mechanisms by which resin-based materials mediate their adverse effects have not been completely elucidated. Here we show that 2-hydroxyethyl methacrylate (HEMA) induces apoptotic cell death in oral keratinocytes and immune cells through the intrinsic cell death pathway. Functional loss and cell death induced by HEMA was significantly inhibited in the presence of N-acetyl cysteine (NAC) treatment. In addition, HEMA induced a decrease in mitochondrial membrane potential, and an increase in cleaved caspases was potently inhibited in the presence of NAC treatment. Overall, the results reported in this article indicate that NAC is an effective chemoprotectant that can safely be used to protect the pulp and the surrounding tissues from adverse effects of dental restorative and endodontic materials.

  14. Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan.

    PubMed

    dos Santos, K S C R; Coelho, J F J; Ferreira, P; Pinto, I; Lorenzetti, S G; Ferreira, E I; Higa, O Z; Gil, M H

    2006-03-09

    Chitosan based membranes to be applied on wound healing as topical drug delivery systems were developed by graft copolymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto chitosan using cerium ammonium nitrate as chemical initiator. Evidence for graft copolymerization of the vinyl monomers onto chitosan was obtained by FTIR and DMTA. Swelling degree, cytotoxicity, thrombogenicity and haemolytic activity of these membranes were evaluated. Chitosan-graft-AA-graft-HEMA showed to be the best matrix for drug delivery systems than chitosan-graft-AA because it retains good swelling properties, but the content in HEMA has improved cytocompatibility, hemocompatibility and thrombogenic character.

  15. The effect of octadecyl chain immobilization on the hemocompatibility of poly (2-hydroxyethyl methacrylate).

    PubMed

    Fischer, Marion; Baptista, Catarina P; Gonçalves, Inês C; Ratner, Buddy D; Sperling, Claudia; Werner, Carsten; Martins, Cristina L; Barbosa, Mário A

    2012-11-01

    Albumin-scavenging surfaces decorated with n-alkyl chains represent an established strategy for blood-contacting applications. To evaluate this concept, a set of poly (2-hydroxyethyl methacrylate) (pHEMA) films modified with different amounts of octadecyl isocyanate (C18) was investigated in an in vitro hemocompatibility assay using freshly drawn human whole blood. In addition, the hydrogel materials were thoroughly characterized with respect to changes in wettability and elasticity, which accompanied the gradual chemical modification of pHEMA. An increase of the surface C18 content induced enhanced hydrophobicity and stiffness. Immobilization of C18 chains was found to substantially reduce the coagulation activation and the complement activation by the pHEMA films. Platelet adhesion and degranulation (PF4 release) were similar on the modified and the unmodified pHEMA. Platelet adhesion to pHEMA hydrogels was lower than the polytetrafluoroethylene reference. We conclude that the immobilization of octadecyl chains improved the hemocompatibility of pHEMA materials under conditions that might be encountered in low shear blood flow.

  16. Development of sustained antimicrobial-release systems using poly(2-hydroxyethyl methacrylate)/trimethylolpropane trimethacrylate hydrogels.

    PubMed

    Kitagawa, Haruaki; Takeda, Kahoru; Kitagawa, Ranna; Izutani, Naomi; Miki, Saeki; Hirose, Nanako; Hayashi, Mikako; Imazato, Satoshi

    2014-10-01

    Reconstructive materials with sustained antimicrobial effects could be useful for preventing infectious diseases in an environment containing indigenous bacteria or fungi such as the oral cavity. With the objective of applying a non-biodegradable hydrogel to resin-based materials as a reservoir for water-soluble antimicrobials, novel hydrogels consisting of 2-hydroxyethyl methacrylate (HEMA) and trimethylolpropane trimethacrylate (TMPT) were fabricated. Cetylpyridinium chloride (CPC) was loaded into five hydrogels comprising different ratios of HEMA/TMPT, and their ability to release as well as to be recharged with CPC was examined in vitro. A polyHEMA/TMPT hydrogel comprising 50% HEMA/50% TMPT could be effectively loaded and recharged with CPC by immersion into a CPC solution, demonstrating the longest release of CPC, above the concentration required to inhibit bacteria and fungi. The binding of CPC to the hydrogels was mainly through hydrophobic interaction. Loading of CPC into a hydrogel by mixing CPC powder with the HEMA/TMPT monomer before polymerization resulted in marked extension of the initial CPC-release period. The CPC-pre-mixed hydrogel was confirmed to exhibit antibacterial activity by agar diffusion tests. It is possible to achieve a sustained release system for antimicrobials by pre-mix loading and recharging CPC into a 50% HEMA/50% TMPT hydrogel.

  17. Transcriptome modifications in human gingival fibroblasts exposed to 2-hydroxyethyl methacrylate.

    PubMed

    Di Nisio, Chiara; D'Aurora, Marco; di Giacomo, Viviana; Stuppia, Liborio; Cataldi, Amelia; Gatta, Valentina

    2016-05-10

    2-Hydroxyethyl methacrylate (HEMA),a tooth filling material, was proven to have toxic effects on different cell types, including human gingival fibroblasts (HGFs), and to be able to influence odontoblast vitality. The aim of the present study was to assess the differential transcriptome modulation induced by low HEMA concentration in cultured HGFs. RNA extracted from cultured HGFs exposed to 3 mmol/l HEMA for 24 or 96 h underwent a whole genome microarray analysis. Data analysis showed the presence of two gene clusters, composed by 310 transcripts differentially expressed after 24- and 96-h HEMA treatment compared to controls. Functional analysis demonstrated that these transcripts are mainly involved in cellular survival and death, and inflammatory response. The study highlighted an overall damage induced by HEMA exposure at both 24 and 96 h, mainly leading to a proliferation impairment. Interestingly, 24-h HEMA treatment seems to induce the cells to trigger repair mechanisms, evidencing an early compensatory response, whereas 96-h incubation appears to cause the occurrence of apoptosis as a consequence of the chronic damage.

  18. Polymer brushes on carbon nanotubes by thiol-lactam initiated radical polymerization of 2-hydroxyethyl methacrylate.

    PubMed

    Rashid, Md Harun-Or; Lee, Won-Ki; Hong, Seong-Soo; Park, Jong Myung; Kim, Hyun Gyu; Lim, Kwon Taek

    2012-01-01

    Water-soluble polymer brushes with multi-walled carbon nanotubes (MWNTs) as backbones were synthesized by grafting 2-hydroxyethyl methacrylate (HEMA) from surface functionalized MWNTs via in situ surface thiol-lactam initiated radical polymerization. MWNTs were functionalized with 2-mercaptoethanol and used as initiators in the polymerization of HEMA in the presence of butyrolactam. FT-IR, XPS, 1H NMR, GPC and TGA were used to determine chemical structure and the grafted polymer quantities of the resulting product. The covalent bonding of PHEMA to the MWNTs dramatically improved the water dispersibility of MWNTs. The average thicknesses of the polymer brushes in the functionalized MWNTs were detected with electron microscopy (SEM and TEM) and images indicated that the nanotubes were coated with polymer layer.

  19. Radiation graft copolymerization of 2-hydroxyethyl methacrylate onto poly (γ-methyl L-glutamate) membrane

    NASA Astrophysics Data System (ADS)

    Yue-E, Fang; Xia, Zhao; Wu, Ge Xue

    1997-11-01

    Radiation-induced grafting Copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto poly(γ-methyl L-glutamate)(PMLG) membrane was researched in aqueous solution in the absence of oxygen. The grafted weight increases with increasing water content in the grafting system. According to the values of the contact angles, the surface free energy, the interfacial free energy, and the adhesive work of the membranes with deionized water were calculated. Photoacoustic fourier transform infrared spectroscopy and electron spectroscopy were used for chemical analysis for the study of the surface composition of grafted membrane. From scanning electron micrographs and wide-angle X-ray diffraction profiles we found that the radiation-induced graft copolymerization of HEMA onto PMLG membrane in water as solvent was carried out to be a graft in bulk.

  20. Patterned poly(2-hydroxyethyl methacrylate) brushes on silicon surfaces behave as "tentacles" to capture ferritin from aqueous solution.

    PubMed

    Chen, Jem-Kun; Chen, Zong-Yan; Lin, Han-Ching; Hong, Po-Da; Chang, Feng-Chih

    2009-07-01

    We have used a very large scale integration process to generate well-defined patterns of polymerized 2-hydroxyethyl methacrylate (HEMA) on patterned Si(100) surfaces. An atom transfer radical polymerization initiator covalently bonded to the patterned surface was employed for the graft polymerization of HEMA to prepare the poly(2-hydroxyethyl methacrylate) (PHEMA) brushes. After immersing wafers presenting lines of these polymers in water and cyclohexane, we observed brush- and mushroom-like regions, respectively, for the PHEMA brushes, with various pattern resolutions. The PHEMA brushes behaved as "tentacles" that captured ferritin complexes from aqueous solution through entanglement between the brushes and the ferritin proteins, whose ferritins were trapped due to the collapsing of the PHEMA. Using high-resolution scanning electron microscopy, we observed patterned ferritin iron cores on the Si surface after thermal removal of the patterned PHEMA brushes and ferritin protein sheaths.

  1. Involvement of fractal geometry on solute permeation through porous poly (2-hydroxyethyl methacrylate) membranes.

    PubMed

    Yanagawa, Fumiki; Onuki, Yoshinori; Morishita, Mariko; Takayama, Kozo

    2006-01-10

    Fractal geometry was applied to quantify the complexity of an internal structure of porous membranes prepared with poly(2-hydroxyethyl methacrylate) (pHEMA). The porous pHEMA membranes were synthesized by means of free-radical solution polymerization. Boundary lines of the porous structures in the pHEMA membrane were taken by a scanning electron microscope as image data, and these images were fed into a computer to estimate the fractal dimension. The boundary images of porous pHEMA membranes were observed to be a typical fractal and their complexity was quantified as a non-integral fractal dimension. The permeation of fluorescein isothiocyanate-labeled dextran, molecular weight 4400 (FD-4) as a model penetrant through the porous pHEMA membrane was determined using water-jacket type two-chamber diffusion cells. A fairly good negative relationship between the permeability coefficient of FD-4 and the fractal dimension was observed, suggesting the usefulness of the fractal dimension as a novel means for evaluating solute permeation through the porous membranes.

  2. Biodegradation of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly{(2-hydroxyethyl methacrylate)-co-[poly(ethylene glycol) methyl ether methacrylate]} hydrogels containing peptide-based cross-linking agents.

    PubMed

    Casadio, Ylenia S; Brown, David H; Chirila, Traian V; Kraatz, Heinz-Bernhard; Baker, Murray V

    2010-11-08

    PHEMA-peptide and P[HEMA-co-(MeO-PEGMA)]-peptide conjugate hydrogels [where PHEMA = poly(2-hydroxyethyl methacrylate; PEGMA = poly(ethylene glycol) methacrylate] were readily prepared via photoinitiated free-radical polymerization in water. The PHEMA-peptide hydrogels were opaque and had a heterogeneous morphology of interconnected polymer droplets, characteristic of polymers that separate from the aqueous phase during the polymerization experiment. The P[HEMA-co-(MeO-PEGMA)]-peptide conjugates were transparent gels with a homogeneous morphology when formed in water, but when formed in aqueous NaCl solutions the P[HEMA-co-(MeO-PEGMA)]-peptide conjugates were also opaque and exhibited the heterogeneous morphology of interconnected polymer droplets. When incubated in solutions containing activated papain, P[HEMA-co-(MeO-PEGMA)]-peptide conjugates underwent degradation that was characterized by macroscopic changes to sample shape and size, sample weight, and microscopic structure. PHEMA-peptide conjugates did not undergo any significant degradation when incubated with papain, although ninhydrin-staining experiments suggested that some peptide cross-linker groups were cleaved during the incubation. The difference in degradation behavior of PHEMA-peptide and P[HEMA-co-(MeO-PEGMA)]-peptide conjugates is attributed to differences in aqueous solubility of PHEMA and P[HEMA-co-(MeO-PEGMA)].

  3. Highly superporous cholesterol-modified poly(2-hydroxyethyl methacrylate) scaffolds for spinal cord injury repair.

    PubMed

    Kubinová, Sárka; Horák, Daniel; Hejčl, Aleš; Plichta, Zdeněk; Kotek, Jiří; Syková, Eva

    2011-12-15

    Modifications of poly(2-hydroxyethyl methacrylate) (PHEMA) with cholesterol and the introduction of large pores have been developed to create highly superporous hydrogels that promote cell-surface interactions and that can serve as a permissive scaffold for spinal cord injury (SCI) treatment. Highly superporous cholesterol-modified PHEMA scaffolds have been prepared by the bulk radical copolymerization of 2-hydroxyethyl methacrylate (HEMA), cholesterol methacrylate (CHLMA), and ethylene dimethacrylate (EDMA) cross-linking agent in the presence of ammonium oxalate crystals to establish interconnected pores in the scaffold. Moreover, 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) was incorporated in the polymerization recipe and hydrolyzed, thus introducing carboxyl groups in the hydrogel to control its swelling and softness. The hydrogels supported the in vitro adhesion and proliferation of rat mesenchymal stem cells. In an in vivo study of acute rat SCI, hydrogels were implanted to bridge a hemisection cavity. Histological evaluation was done 4 weeks after implantation and revealed the good incorporation of the implanted hydrogels into the surrounding tissue, the progressive infiltration of connective tissue and the ingrowth of neurofilaments, Schwann cells, and blood vessels into the hydrogel pores. The results show that highly superporous cholesterol-modified PHEMA hydrogels have bioadhesive properties and are able to bridge a spinal cord lesion.

  4. Poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) Brushes as Peptide/Protein Microarray Substrate for Improving Protein Binding and Functionality.

    PubMed

    Lei, Zhen; Gao, Jiaxue; Liu, Xia; Liu, Dianjun; Wang, Zhenxin

    2016-04-27

    We developed a three-dimensional (3D) polymer-brush substrate for protein and peptide microarray fabrication, and this substrate was facilely prepared by copolymerization of glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) monomers via surface-initiated atom transfer radical polymerization (SI-ATRP) on a glass slide. The performance of obtained poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) (P(GMA-HEMA)) brush substrate was assessed by binding of human IgG with rabbit antihuman IgG antibodies on a protein microarray and by the determination of matrix metalloproteinase (MMP) activities on a peptide microarray. The P(GMA-HEMA) brush substrate exhibited higher immobilization capacities for proteins and peptides than those of a two-dimensional (2D) planar epoxy slide. Furthermore, the sensitivity of the P(GMA-HEMA) brush-based microarray on rabbit antihuman IgG antibody detection was much higher than that of its 2D counterpart. The enzyme activities of MMPs were determined specifically with a low detection limit of 6.0 pg mL(-1) for MMP-2 and 5.7 pg mL(-1) for MMP-9. By taking advantage of the biocompatibility of PHEMA, the P(GMA-HEMA) brush-based peptide microarray was also employed to evaluate the secretion of MMP-2 and MMP-9 by cells cultured off the chip or directly on the chip, and satisfactory results were obtained.

  5. Radiation-grafted polymers for biomaterial applications. I. 2-hydroxyethyl methacrylate: ethyl methacrylate grafting onto low density polyethylene films

    SciTech Connect

    Cohn, D.; Hoffman, A.S.; Ratner, B.D.

    1984-08-01

    Studies were conducted on the radiation grafting of 2-hydroxyethyl methacrylate (HEMA) and ethyl methacrylate (EMA) by the mutual irradation technique onto low density polyethylene. Four different solution concentrations were used, and radiation doses ranged from 0.03 to 0.50 Mrad. Four copolymer compositions having different HEMA:EMA ratios were also studied using two total monomer concentrations. The kinetics of the grafting process demonstrated by the two monomers were basically different. While EMA showed a typical diffusion-controlled kinetic pattern, HEMA exhibited a more complex behavior, the main features of which were an induction period, a slight autoacceleration and a significant drop in graft level after a maximum is reached. The difference in behavior was interpreted in terms of partitioning of monomers into the polyethlene substrate. The surface topography of the grafted films was studied by means of scanning electron microscopy. A mechanism based on osmotic cell formation was suggested for the HEMA graft system. The copolymer systems investigated showed that the graft reaction is faster in the initial stages for higher percentages of EMA in the monomer mixtures; as grafting proceeds the trend is reversed. 24 references, 16 figures, 2 tables.

  6. Smart poly(2-hydroxyethyl methacrylate/itaconic acid) hydrogels for biomedical application

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida Lj; Mićić, Maja M.; Dobić, Sava N.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2010-05-01

    pH- and temperature-sensitive hydrogels, based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) copolymers, were prepared by γ-irradiation and characterized in order to examine their potential use in biomedical applications. The influence of comonomer ratio in these smart copolymers on their morphology, mechanical and thermal properties, biocompatibility and microbe penetration capability was investigated. The mechanical properties of copolymers were investigated using the dynamic mechanical analysis (DMA), while their thermal properties and morphology were examined by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The morphology, mechanical and thermal properties of these hydrogels were found to be suitable for most requirements of biomedical applications. The in vitro study of P(HEMA/IA) biocompatibility showed no evidence of cell toxicity nor any considerable hemolytic activity. Furthermore, the microbe penetration test showed that neither Staphylococcus aureus nor Escherichia coli passed through the hydogel dressing; thus the P(HEMA/IA) dressing could be considered a good barrier against microbes. All results indicate that stimuli-responsive P(HEMA/IA) hydrogels have great potential for biomedical applications, especially for skin treatment and wound dressings.

  7. Epidermal and dermal integration into sphere-templated porous poly(2-hydroxyethyl methacrylate) implants in mice.

    PubMed

    Fukano, Y; Usui, M L; Underwood, R A; Isenhath, S; Marshall, A J; Hauch, K D; Ratner, B D; Olerud, J E; Fleckman, P

    2010-09-15

    Percutaneous medical devices remain susceptible to infection and failure. We hypothesize that healing of the skin into the percutaneous device will provide a seal, preventing bacterial attachment, biofilm formation, and subsequent device failure. Porous poly(2-hydroxyethyl methacrylate) [poly(HEMA)] with sphere-templated pores (40 microm) and interconnecting throats (16 microm) were implanted in normal C57BL/6 mice for 7, 14, and 28 days. Poly(HEMA) was either untreated, keeping the surface nonadhesive for cells and proteins, or modified with carbonyldiimidazole (CDI) or CDI reacted with laminin 332 to enhance adhesion. No clinical signs of infection were observed. Epidermal and dermal response within the poly(HEMA) pores was evaluated using light and transmission electron microscopy. Cells (keratinocytes, fibroblasts, endothelial cells, inflammatory cells) and basement membrane proteins (laminin 332, beta4 integrin, type VII collagen) could be demonstrated within the poly(HEMA) pores of all implants. Blood vessels and dermal collagen bundles were evident in all of the 14- and 28-day implants. Fibrous capsule formation and permigration were not observed. Sphere-templated polymers with 40 microm pores demonstrate an ability to recapitulate key elements of both the dermal and the epidermal layers of skin. Our morphological findings indicate that the implant model can be used to study the effects of biomaterial pore size, pore interconnect (throat) size, and surface treatments on cutaneous biointegration. Further, this model may be used for bacterial challenge studies.

  8. Effect of 2-hydroxyethyl methacrylate pre-treatment on micro-tensile bond strength of resin composite to demineralized dentin.

    PubMed

    Doi, J; Itota, T; Torii, Y; Nakabo, S; Yoshiyama, M

    2004-11-01

    The purpose of this study was to evaluate the effect of 2-hydroxyethyl methacrylate (HEMA) application on the micro-tensile bond strength of resin composite to demineralized dentin. Artificially demineralized lesions were formed on bovine dentin surfaces and treated with 10, 30, 50, 70 and 100 wt% HEMA aqueous solution. The surfaces were then applied and covered with SE Bond and AP-X according to the manufacturer's instruction. After immersion in 37 degrees C water for 24 h, bond strength were measured using a universal testing machine. Bond strengths to both demineralized dentin and normal dentin, without HEMA application, were also measured. Scanning electron microscopic (SEM) observation and confocal laser scanning microscopy (CLSM) analysis at the resin-dentin interface were also performed. The bond strength data were statistically compared with anova and Scheffe's test (P < 0.05). Bond strength to demineralized dentin treated with over 30 wt% HEMA aqueous solution were significantly higher than that to demineralized dentin without HEMA application, but significantly lower than that to normal dentin. SEM observation revealed that the hybrid layer and resin-tags thickened and lengthened with HEMA application. In CLSM, the diffusion of adhesive primer into demineralized dentin increased with HEMA application. These results indicated that HEMA application might increase the bond strength to demineralized dentin by the enhancement of resin monomer penetration of HEMA.

  9. Saliva improves Streptococcus mitis protective effect on human gingival fibroblasts in presence of 2-hydroxyethyl-methacrylate.

    PubMed

    Di Giulio, Mara; di Giacomo, Viviana; Di Campli, Emanuela; Di Bartolomeo, Soraya; Zara, Susi; Pasquantonio, Guido; Cataldi, Amelia; Cellini, Luigina

    2013-08-01

    This study aimed to investigate the effect of saliva on Streptococcus mitis free cells and on S. mitis/human gingival fibroblasts (HGFs) co-culture model, in presence of 2-hydroxyethyl-methacrylate (HEMA). The bacterial aggregation both in the planktonic phase and on HGFs, as well as the apoptotic and necrotic eukaryotic cells amount were analyzed, in presence of saliva and/or HEMA. The aggregation test revealed a significant saliva aggregation effect on S. mitis strains compared to the untreated sample. No significant differences were recorded in the amount of culturable bacteria in all studied conditions; however, from microscopy images, the saliva/HEMA combining effect induced a significant bacterial aggregation and adhesion on HGFs. HEMA treatment decreased viable eukaryotic cell number with a parallel increment of necrotic cells, but when saliva was added to the co-culture, the viable cells percentage increased to a value comparable to the control sample.

  10. Manufacture of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) hydrogel tubes for use as nerve guidance channels.

    PubMed

    Dalton, Paul D; Flynn, Lauren; Shoichet, Molly S

    2002-09-01

    Hydrogel tubes of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (p(HEMA-co-MMA)) made by liquid-liquid centrifugal casting are being investigated as potential nerve guidance channels in the central nervous system. An important criterion for the nerve guidance channel is that its mechanical properties are similar to those of the spinal cord, where it will be implanted. The formulated p(HEMA-co-MMA) tubes are soft and flexible, consisting of a gel-like outer layer, and an interconnected macroporous, inner layer. The relative thickness of the gel phase to macroporous phase is controlled by the formulation chemistry, and specifically by the ratio of co-monomers, HEMA and MMA. By varying the surface chemistry of the mold within which the tubes are synthesized, tubes were prepared with either a "cracked" or a smooth outer morphology. Tubes with the cracked outer morphology had periodic channels that traversed the wall of the tube, which resulted in a lower modulus than smooth outer morphology tubes, yet likely greater diffusive permeability. For tubes (and not rods) to be formed, phase separation must precede gelation as is detailed in a formulation phase diagram for HEMA, MMA and water. The tensile elastic modulus of p(HEMA-co-MMA) tubes reflected the formulation chemistry, with greater moduli (up to 400 kPa) recorded for tubes having 10 wt% MMA. The p(HEMA-co-MMA) tubes therefore had similar mechanical properties to those of the spinal cord, which has a reported elastic modulus range between 200 and 600 kPa.

  11. Effect of 2-Hydroxyethyl Methacrylate on Antioxidant Responsive Element-Mediated Transcription: A Possible Indication of Its Cytotoxicity

    PubMed Central

    Orimoto, Ai; Suzuki, Takahiro; Ueno, Atsuko; Kawai, Tatsushi; Nakamura, Hiroshi; Kanamori, Takao

    2013-01-01

    Background The resin monomer 2-hydroxyethyl methacrylate (HEMA) is known to be more cytotoxic than methyl methacrylate (MMA). Using a luciferase reporter assay system, we previously showed that MMA activates the glutathione S-transferase alpha 1 gene (Gsta1) promoter through the anti-oxidant responsive element (ARE). However, it is not known whether HEMA induces ARE-mediated transcription. Methodology/Principal Findings We further developed the reporter system and studied the concentration-dependent effect of HEMA on ARE enhancer activity. The revised system employed HepG2 cells stably transfected with a destabilized luciferase reporter vector carrying 2 copies of the 41-bp ARE region of Gsta1. In this system, MMA increased ARE activity by 244-fold at 30 mM; HEMA augmented ARE activity at 3 mM more intensely than MMA (36-fold versus 11-fold) and was equipotent as MMA at 10 mM (56-fold activation); however, HEMA failed to increase ARE activity at 30 mM. In HepG2 cells, HEMA detectably lowered the cellular glutathione levels at 10 mM and cell viability at 30 mM, but MMA did not. Conclusions These results suggest that the low-concentration effect of HEMA on ARE activity reflects its cytotoxicity. Our reporter system used to examine ARE activity may be useful for evaluating cytotoxicities of resin monomers at concentrations lower than those for which cell viabilities are reduced. PMID:23516576

  12. 2-Hydroxyethyl methacrylate-induced apoptosis through the ATM- and p53-dependent intrinsic mitochondrial pathway.

    PubMed

    Schweikl, Helmut; Petzel, Christine; Bolay, Carola; Hiller, Karl-Anton; Buchalla, Wolfgang; Krifka, Stephanie

    2014-03-01

    Resin monomers of dental composites like 2-hydroxyethyl methacrylate (HEMA) disturb cell functions including responses of the innate immune system, mineralization and differentiation of dental pulp-derived cells, or induce cell death via apoptosis. The induction of apoptosis is related to the availability of the antioxidant glutathione, although a detailed understanding of the signaling pathways is still unknown. The present study provides insight into the causal relationship between oxidative stress, oxidative DNA damage, and the specific signaling pathway leading to HEMA-induced apoptosis in RAW264.7 mouse macrophages. The differential expression of the antioxidative enzymes superoxide dismutase, glutathione peroxidase, and catalase in HEMA-exposed cells indicated oxidative stress, which was associated with the cleavage of pro-caspase 3 as a critical apoptosis executioner. A 2-fold increase in the amount of mitochondrial superoxide anions after a 24 h exposure to HEMA (6-8 mM) was paralleled by a considerable decrease in the mitochondrial membrane potential (MMP). Additionally, expression of proteins critical for the signaling of apoptosis through the intrinsic mitochondrial pathway was detected. Transcription-dependent and transcription-independent mechanisms of p53-regulated apoptosis were activated, and p53 was translocated from the cytosol to mitochondria. HEMA-induced transcriptional activity of p53 was indicated by increased levels of PUMA localized to mitochondria as a potent inducer of apoptosis. The expression of Bcl-xL and Bax suggested that cells responded to stress caused by HEMA via the activation of a complicated and antagonistic machinery of pro- and anti-apoptotic Bcl-2 family members. A HEMA-induced and oxidative stress-sensitive delay of the cell cycle, indicating a DNA damage response, occurred independent of the influence of KU55399, a potent inhibitor of ATM (ataxia-telangiectasia mutated) activity. However, ATM, a protein kinase which

  13. Poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid): synthesis, physico-chemical characterisation and nafcillin carrier.

    PubMed

    Zecheru, Teodora; Rotariu, Traian; Rusen, Edina; Mărculescu, Bogdan; Miculescu, Florin; Alexandrescu, Laura; Antoniac, Iulian; Stancu, Izabela-Cristina

    2010-10-01

    In the present study polymeric microbeads of poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid) or p(HEMA-co-dDMA-co-AA) were synthesised and characterized through FT-IR and scanning electron microscopy (SEM); their swelling behavior against saline solution was explored and their in vitro cytotoxicity was evaluated. Further, in order to elucidate kinetic aspects regarding the ternary system p(HEMA-co-dDMA-co-AA), a mathematical model of the reactivity ratios of the comonomers in the terpolymer has been conceived and analyzed. An intensified tendency of AA units accumulation in the copolymer has been noticed, in spite of HEMA units, while dDMA conserves in the copolymer the fraction from the feed. Three compositions have been selected for nafcillin-loading and their in vitro release capacity was evaluated. The compositions of 80:10:10 and 75:10:15 M ratios appear suitable for further in vivo testing, in order to be used as drug delivery systems in the treatment of different osseous diseases.

  14. Feedback-regulated paclitaxel delivery based on poly(N,N-dimethylaminoethyl methacrylate-co-2-hydroxyethyl methacrylate) nanoparticles.

    PubMed

    You, Jin-Oh; Auguste, Debra T

    2008-04-01

    pH-Sensitive poly(N,N-dimethylaminoethyl methacrylate (DMAEMA)/2-hydroxyethyl methacrylate (HEMA)) nanoparticles were prepared for the triggered release of paclitaxel within a tumor microenvironment. Tumors exhibit a lower extracellular pH than normal tissues. We show that paclitaxel release from DMAEMA/HEMA particles can be actively triggered by small, physiological changes in pH (within 0.2-0.6 pH units). Monodispersed nanoparticles were synthesized by forming an O/W emulsion followed by photopolymerization. Particles were characterized by transmission electron microscopy, dynamic light scattering, electrophoresis, and cytotoxicity. High release rates and swelling ratios are achieved at low pH, low crosslinking density, and high content of DMAEMA. Paclitaxel release is limited to 9% of the payload at pH 7.4 after a 2-h incubation at 37 degrees C. After adjusting to pH 6.8, 25% of the payload is released within 2h. Cell viability studies indicate that pH-sensitive DMAEMA/HEMA nanoparticles are not cytotoxic and may be used as an efficient, feedback-regulated drug delivery carrier.

  15. Laser-assisted high-pressure-induced polymerization of 2-(hydroxyethyl)methacrylate.

    PubMed

    Evlyukhin, E; Museur, L; Traore, M; Nikitin, S M; Zerr, A; Kanaev, A

    2015-02-26

    We report on a successful room-temperature polymerization of 2-(hydroxyethyl)methacrylate (HEMA) under high pressure. The polymerization is observed in a limited range of pressures 0.1 to 1.6 GPa without the use of any initiator. When the compressed sample is irradiated at 488 or 355 nm by a laser, the polymerization reaction rate is increased by a factor of 10 or 30, respectively. Moreover, the shift of the laser wavelength to the UV improves the polymerization yield of the recovered sample to 84%. The catalysis of the polymerization process by light results from a one-photon-assisted electron transfer to π* antibonding states of the monomer molecule. The observed polymerization is irreversible and almost complete, which makes this synthesis process suitable for applications.

  16. Multipin peptide synthesis at the micromole scale using 2-hydroxyethyl methacrylate grafted polyethylene supports.

    PubMed

    Valerio, R M; Bray, A M; Campbell, R A; Dipasquale, A; Margellis, C; Rodda, S J; Geysen, H M; Maeji, N J

    1993-07-01

    The multipin peptide synthesis procedure has been adapted to allow the synthesis of peptides at micromole loadings. The original solid pin support was replaced with a detachable crown-shaped polyethylene support with an increased surface area. In addition, the polyethylene crowns were radiation-grafted with 2-hydroxyethyl methacrylate monomer instead of acrylic acid to yield hydroxy functionalized supports with a larger concentration of polymer and hence a larger peptide capacity. Fmoc-beta-Alanine was directly esterified to the HEMA hydroxy groups with subsequent addition of a diketopiperazine-forming handle for peptide attachment. Peptides varying in length from 10 to 25 residues were assembled at a number of loadings from 1.0 to 2.2 mumol. Purity of peptides at all loadings was equal to, and in some instances superior to, that achieved on conventional solid-phase supports.

  17. Jet-Splitting Instability in Electrospinning of POLY(2-HYDROXYETHYL Methacrylate)

    NASA Astrophysics Data System (ADS)

    Koombhongse, Sureeporn; Reneker, Darrell H.

    2000-03-01

    The electrically charged surface of a polymer fluid becomes unstable when the electrical forces overcome forces of surface tension. A charged jet is then ejected from the surface. The electrical charge carried with the ejected jet can excite instabilities of the jet, which affect its path. A bending instability [1] is frequently observed. In some solutions of poly(2-hydroxyethyl methacrylate) (HEMA), high speed videographic images show that a splitting instability also occurs for the more concentrated solutions. In the splitting instability, a smaller, straight jet is ejected from the primary jet. The splitting instability may be observed before or while the bending instability is growing. In a 20instabilities are dominant. The bending instability became observable when the concentration was reduced to 16more dominant when the concentration was further reduced to 16 1. D. H. Reneker, A. L. Yarin, H. Fong, S. Koombhongse, J. App. Phys, to be published.

  18. Lysine-poly(2-hydroxyethyl methacrylate) modified polyurethane surface with high lysine density and fibrinolytic activity.

    PubMed

    Li, Dan; Chen, Hong; Wang, Shasha; Wu, Zhaoqiang; Brash, John L

    2011-03-01

    We have developed a potentially fibrinolytic surface in which a bioinert polymer is used as a spacer to immobilize lysine such that the ε-amino group is free to capture plasminogen when in contact with blood. Adsorbed plasminogen can be activated to plasmin and potentially dissolve nascent clots formed on the surface. In previous work lysine was immobilized through a poly(ethylene glycol) (PEG) spacer; however, the graft density of PEG was limited and the resulting adsorbed quantity of plasminogen was insufficient to dissolve clots efficiently. The aim of the present work was to optimize the surface using graft-polymerized poly(2-hydroxyethyl methacrylate) (poly(HEMA)) as a spacer to increase the grafting density of lysine. Such a poly(HEMA)-lysine modified polyurethane (PU) surface is expected to have increased plasminogen binding capacity and clot lysing efficiency compared with PEG-lysine modified PU. A lysine density of 2.81 nmol cm(-2) was measured on the PU-poly(HEMA)-Lys surface vs. 0.76 nmol cm(-2) on a comparable PU-PEG-Lys surface reported previously. The poly(HEMA)-lysine-modified surface was shown to reduce non-specific (fibrinogen) adsorption while binding plasminogen from plasma with high affinity. With increased plasminogen binding capacity these surfaces showed more rapid clot lysis (20 min) in a standard in vitro assay than the corresponding PEG-lysine system (40 min). The data suggest that poly(HEMA) is superior to PEG when used as a spacer in the immobilization of bioactive molecules at high density. This method of modification may also provide a generic approach for preparing bioactive PU surfaces of high activity and low non-specific adsorption of proteins.

  19. Swelling and thermodynamic studies of temperature responsive 2-hydroxyethyl methacrylate/itaconic acid copolymeric hydrogels prepared via gamma radiation

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida L. J.; Mićić, Maja M.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2007-08-01

    The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 °C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 °C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 °C, in order to evaluate their potential for medical applications.

  20. Sensitization potential of dental resins: 2-hydroxyethyl methacrylate and its water-soluble oligomers have immunostimulatory effects.

    PubMed

    Fukumoto, Izumi; Tamura, Atsushi; Matsumura, Mitsuaki; Miura, Hiroyuki; Yui, Nobuhiko

    2013-01-01

    The immunostimulatory effects of the representative dental resin monomer 2-hydroxyethyl methacrylate (HEMA), a HEMA derivative that does not contain a double bond (2-hydroxyethyl isobutyrate, HEIB), and polymerized water-soluble oligomers of HEMA (PHEMA) were investigated. It is known that expression levels of either or both of CD54 and CD86 in THP-1 cells are increased by exposure to sensitizing substances. In this study, the expression levels of CD54 and CD86, the production of reactive oxygen species (ROS), and the viability of the cells were measured after 24 h of incubation with these materials at different concentrations. The concentrations of the materials that induced the expression of both CD54 and CD86 were low in the following order: NiSO4, HEMA, and methyl methacrylate (MMA). These results indicate that these dental resin monomers have lower sensitizing potentials than NiSO4. Although HEIB, which lacks a double bond, resulted in negligible ROS production and reduced cytotoxicity than HEMA, it induced the expression of CD54 and CD86. Comparison of the results for HEMA and HEIB indicates that dental resin monomer-induced sensitization may be related not only to the oxidative stress related to the methacryloyl group but also to the structures of these compounds. Of particular interest is the result that a water-soluble PHEMA oligomer with a relatively high-molecular weight also exhibited negligible cytotoxicity, whereas the expression level of CD54 increased after exposure to PHEMA at a high concentration. This result serves as a warning that polymerized substances also have the potential to induce sensitization. This study provides insight into the nature of allergic responses to dental resin materials in clinical use and may facilitate the development of more biocompatible restorative materials in the future.

  1. Magnetic poly(2-hydroxyethyl methacrylate) microspheres for affinity purification of antibodies for early diagnosis of multiple sclerosis patients.

    PubMed

    Horak, Daniel; Hlidkova, Helena; Kit, Yurii; Stoika, Rostyslav; Antonyuk, Volodymyr; Myronovsky, Severyn

    2017-03-28

    The aim of this work is to develop new magnetic polymer microspheres with functional groups available for easy protein and antibody binding. Monodisperse macroporous poly(2-hydroxyethyl methacrylate) (PHEMA-COOH) microspheres ca. 4 µm in diameter and containing ~ 1 mmol COOH/g were synthesized by multistep swelling polymerization of 2-hydroxyethyl methacrylate (HEMA), ethylene dimethacrylate (EDMA), and [(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA), which was followed by MCMEMA hydrolysis. The microspheres were rendered magnetic by precipitation of iron oxide inside the pores, which made them easily separable in a magnetic field. Properties of the resulting magnetic poly(2-hydroxyethyl methacrylate) (mgt.PHEMA) particles with COOH functionality were examined by scanning and transmission electron microscopy (SEM and TEM), static volumetric adsorption of helium and nitrogen, mercury porosimetry, Fourier-transform infrared (FTIR) and atomic absorption spectroscopy (AAS), and elemental analysis. Mgt.PHEMA microspheres were coupled with p46/Myo1C protein purified from blood serum of multiple sclerosis (MS) patients, which enabled easy isolation of monospecific anti-p46/Myo1C immunoglobulin G (IgG) antibodies from crude antibody preparations of mouse blood serum. High efficiency of this approach was confirmed by SDS-PAGE, Western blot, and dot blot analyses. The newly developed mgt.PHEMA microspheres conjugated with a potential disease biomarker, p46/Myo1C protein, are thus a promising tool for affinity purification of antibodies, which can improve diagnosis and treatment of MS patients.

  2. Immobilization of enzymes on 2-hydroxyethyl methacrylate and glycidyl methacrylate copolymer brushes.

    PubMed

    Ren, Tanchen; Mao, Zhengwei; Moya, Sergio Enrique; Gao, Changyou

    2014-08-01

    The immobilization of enzymes is of paramount importance to maintain their activity and stability. In this study, surface-initiated atom-transfer radical polymerization was applied to prepare poly(2-hydroxyethyl methacrylate)-block-poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) brushes on glass slides. The polymerization kinetics was followed by using a quartz crystal microbalance with dissipation monitoring and ellipsometry in terms of mass and thickness growth, respectively. The surface chemical compositions of the obtained polymer brushes were characterized by X-ray photoelectron spectroscopy. Their mass, thickness, and enzyme-immobilization ability could be easily tuned by the initiator reaction time, monomer ratio, and polymerization time. The antibacterial activity and stability of the immobilized lysozymes were studied by fluorescent staining and bacteria lysis assay, which revealed that the lysozymes on the copolymer brushes had good stability during storage at 4 °C for up to 30 days.

  3. Antioxidant Properties of 2-Hydroxyethyl Methacrylate-Based Copolymers with Incorporated Sterically Hindered Amine.

    PubMed

    Poláková, L; Raus, V; Kostka, L; Braunová, A; Pilař, J; Lobaz, V; Pánek, J; Sedláková, Z

    2015-09-14

    A series of model linear copolymers of 2-hydroxyethyl methacrylate (HEMA) and a sterically hindered amine derivative [N-(2,2,6,6-tetramethyl-piperidin-4-yl)methacrylamide (HAS)] were synthesized and characterized. Scavenging activities of the copolymers against reactive oxygen species (peroxyl and hydroxyl radicals) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals were determined. It was found that copolymers with medium HAS content (3.5-4.0 mol %) were better scavengers than copolymers with lower and higher HAS content and also than polyHEMA and polyHAS homopolymers and the HAS monomer. Importantly, these copolymers compared favorably even to established low-molecular weight antioxidant standards (BHA and dexpanthenol). Monomer reactivity ratios were determined, and the microstructure of the copolymers was assessed. Subsequently, cross-linked copolymers in the powder and film forms with optimal HAS content were synthesized. Their scavenging activities against the three types of radicals were determined, revealing that these hydrogels are potent scavengers of reactive oxygen species.

  4. Proton-conducting polymer membrane comprised of a copolymer of 2-acrylamido-2-methylpropanesulfonic acid and 2-hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Walker, Charles W.

    In order to identify a proton-conducting polymer membrane suitable for replacing Nafion ® 117 in direct methanol fuel cells (DMFC), we prepared a cross-linked copolymer of hydrophilic 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 2-hydroxyethyl methacrylate (HEMA). Fumed silicas were also added in an attempt to increase the amount of water adsorbed by the membrane and to enhance water retention. Hydrated copolymer membranes adsorbed significantly more water than Nafion ® 117, but were no better at retaining water during drying under ambient conditions. Films composed of 4% AMPS—96% HEMA had a room temperature proton conductivity of 0.029 S cm -1, which increased to 0.06 S cm -1 at 80 °C.

  5. Relationship between water structure and properties of poly(methyl methacrylate-b-2-hydroxyethyl methacrylate) by solid-state NMR.

    PubMed

    Mochizuki, Akira; Miwa, Yuko; Miyoshi, Riko; Namiki, Takahiro

    2017-03-22

    We previously reported that the platelet compatibility of methyl methacrylate (MMA)-2-hydroxyethyl methacrylate (HEMA) diblock copolymers is related to the characteristic water structure in the copolymer, as the copolymer has an excess amount of nonfreezing water when compared with that estimated from the amounts of water in HEMA and MMA homopolymers. Thus, in this study, the relationship between water structure and polymer structure, including the heterogeneity and mobility of the copolymer, was investigated using differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy. The prepared copolymers were classified into two groups: copolymers with a short, constant polyMMA segment length (Mn = ~2900) and copolymers with a constant polyHEMA segment length (Mn = ~9500), whereas the lengths of the counter segments varied. DSC analysis showed that when the polyMMA and polyHEMA segment lengths are similar, the amount of nonfreezing water increases, regardless of the total molecular weight of the copolymer. NMR analysis showed that heterogeneity of the copolymer is enhanced and the mobility of the copolymer decreases when the segment lengths are similar. These findings suggested that the excess amount of nonfreezing water is formed when the properties of water near the HEMA unit change from freezing to nonfreezing owing to interactions with the MMA unit. In addition, it is suggested that the heterogeneity of the copolymer structure or the mobility of the polymer are involved in the generation of excess nonfreezing water.

  6. Study of the water structure in poly(methyl methacrylate-block-2-hydroxyethyl methacrylate) and its relationship to platelet adhesion on the copolymer surface.

    PubMed

    Mochizuki, Akira; Namiki, Takahiro; Nishimori, Yusuke; Ogawa, Haruki

    2015-01-01

    The water structure and platelet compatibility of poly(methyl methacrylate (MMA)-block-2-hydroxyethyl methacrylate (HEMA)) were investigated. The molecular weight (Mn) of the polyHEMA segment was kept constant (average: 9600), while the Mn of the polyMMA segment was varied from 1340 to 7390. The equilibrium water content of the copolymers was found to be mainly governed by the HEMA content. The water structure in the copolymers was characterized in terms of the amounts of non-freezing and freezing water (abbreviated as Wnf and Wfz, respectively) using differential scanning calorimetry. It was found that the Wnf for the copolymers were higher than those estimated from the Wnf for the HEMA and MMA homopolymers and that the amount of excess non-freezing water depended on the polyMMA segment length. In addition, X-ray diffraction analysis revealed that some of the copolymers had cold-crystallizable water. These facts suggested that the polyMMA segments were involved in determining the water structures in the copolymers. Furthermore, the platelet compatibility of the copolymers was improved as compared to that of the HEMA homopolymer. It was therefore concluded that the platelet compatibility of the copolymer was related to the amount of excess non-freezing water.

  7. Oligonucleotide Immobilization and Hybridization on Aldehyde-Functionalized Poly(2-hydroxyethyl methacrylate) Brushes.

    PubMed

    Bilgic, Tugba; Klok, Harm-Anton

    2015-11-09

    DNA biosensing requires high oligonucleotide binding capacity interface chemistries that can be tuned to maximize probe presentation as well as hybridization efficiency. This contribution investigates the feasibility of aldehyde-functionalized poly(2-hydroxyethyl methacrylate) (PHEMA) brush-based interfaces for oligonucleotide binding and hybridization. These polymer brushes, which allow covalent immobilization of oligonucleotides, are prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) of HEMA followed by a postpolymerization oxidation step to generate side chain aldehyde groups. A series of polymer brushes covering a range of film thicknesses and grafting densities was investigated with regard to their oligonucleotide binding capacity as well as their ability to support oligonucleotide hybridization. Densely grafted brushes were found to have probe oligonucleotide binding capacities of up to ∼30 pmol/cm(2). Increasing the thickness of these densely grafted brush films, however, resulted in a decrease in the oligonucleotide binding capacity. Less densely grafted brushes possess binding capacities of ∼10 pmol/cm(2), which did not significantly depend on film thickness. The oligonucleotide hybridization efficiencies, however, were highest (93%) on those brushes that present the lowest surface concentration of the probe oligonucleotide. These results highlight the importance of optimizing the probe oligonucleotide surface concentration and binding interface chemistry. The versatility and tunability of the PHEMA-based brushes presented herein makes these films a very attractive platform for the immobilization and hybridization of oligonucleotides.

  8. Self-assembled rosette nanotubes and poly(2-hydroxyethyl methacrylate) hydrogels promote skin cell functions.

    PubMed

    Sun, Linlin; Li, Dongni; Hemraz, Usha D; Fenniri, Hicham; Webster, Thomas J

    2014-10-01

    The next generation skin of wound healing materials should stimulate skin regeneration by actively promoting appropriate cellular adhesion and proliferation. As materials with novel self-assembling and solidification properties when transitioning from room to body temperatures, rosette nanotubes (RNTs) may be such a proactive material. RNTs resemble naturally occurring nanostructures in the skin (such as collagen and keratin) assembling with noncovalent forces in physiological environments. Presenting desirable bioactive properties, RNTs have been used for various tissue engineering applications including increasing in vivo bone and cartilage regeneration. The objective of the current in vitro study was, for the first time, to improve properties of a commonly used hydrogel (poly(2-hydroxyethyl methacrylate) or pHEMA) for skin regeneration by incorporating one type of novel self-assembled RNTs, called TBL. Results showed for the first time increased keratinocyte and fibroblast proliferation on hydrogels coated with TBLs compared to those not coated with TBL. In this manner, this study provides the first evidence that TBL RNTs are promising for wound healing applications due to their optimal cytocompatibility, solidification, and mechanical properties and, thus, should be further studied for such applications.

  9. Lipase catalyzed HEMA initiated ring-opening polymerization: in situ formation of mixed polyester methacrylates by transesterification.

    PubMed

    Takwa, Mohamad; Xiao, Yan; Simpson, Neil; Malmström, Eva; Hult, Karl; Koning, Cor E; Heise, Andreas; Martinelle, Mats

    2008-02-01

    2-Hydroxyethyl methacrylate (HEMA) was used as initiator for the enzymatic ring-opening polymerization (ROP) of omega-pentadecalactone (PDL) and epsilon-caprolactone (CL). The lipase B from Candida antarctica was found to catalyze the cleavage of the ester bond in the HEMA end group of the formed polyesters, resulting in two major transesterification processes, methacrylate transfer and polyester transfer. This resulted in a number of different polyester methacrylate structures, such as polymers without, with one, and with two methacrylate end groups. Furthermore, the 1,2-ethanediol moiety (from HEMA) was found in the polyester products as an integral part of HEMA, as an end group (with one hydroxyl group) and incorporated within the polyester (polyester chains acylated on both hydroxyl groups). After 72 h, as a result of the methacrylate transfer, 79% (48%) of the initial amount of the methacrylate moiety (from HEMA) was situated (acylated) on the end hydroxyl group of the PPDL (PCL) polyester. In order to prepare materials for polymer networks, fully dimethacrylated polymers were synthesized in a one-pot procedure by combining HEMA-initiated ROP with end-capping using vinyl methacrylate. The novel PPDL dimethacrylate (>95% incorporated methacrylate end groups) is currently in use for polymer network formation. Our results show that initiators with cleavable ester groups are of limited use to obtain well-defined monomethacrylated macromonomers due to the enzyme-based transesterification processes. On the other hand, when combined with end-capping, well-defined dimethacrylated polymers (PPDL, PCL) were prepared.

  10. Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Tomić, S. Lj.; Mićić, M. M.; Filipović, J. M.; Suljovrujić, E. H.

    2007-05-01

    The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks.

  11. Effect of chemical composition on corneal cellular response to photopolymerized materials comprising 2-hydroxyethyl methacrylate and acrylic acid.

    PubMed

    Lai, Jui-Yang

    2013-10-01

    Characterization of corneal cellular response to hydrogel materials is an important issue in ophthalmic applications. In this study, we aimed to investigate the relationship between the feed composition of 2-hydroxyethyl methacrylate (HEMA)/acrylic acid (AAc) and material compatibility towards corneal stromal and endothelial cells. The monomer solutions of HEMA and AAc were mixed at varying volume ratios of 92:0, 87:5, 82:10, 77:15, and 72:20, and were subjected to UV irradiation. Results of electrokinetic measurements showed that an increase in absolute zeta potential of photopolymerized membranes is observed with increasing the volume ratios of AAc/HEMA. Following 4 days of incubation with various hydrogels, the primary rabbit corneal stromal and endothelial cell cultures were examined for viability, proliferation, and pro-inflammatory gene expression. The samples prepared from the solution mixture containing 0-10 vol.% AAc displayed good cytocompatibility. However, with increasing volume ratio of AAc and HEMA from 15:77 to 20:72, the decreased viability, inhibited proliferation, and stimulated inflammation were noted in both cell types, probably due to the stronger charge-charge interactions. On the other hand, the ionic pump function of corneal endothelial cells exposed to photopolymerized membranes was examined by analyzing the Na(+),K(+)-ATPase alpha 1 subunit (ATP1A1) expression level. The presence of material samples having higher anionic charge density (i.e., zeta potential of -38 to -56 mV) may lead to abnormal transmembrane transport. It is concluded that the chemical composition of HEMA/AAc has an important influence on the corneal stromal and endothelial cell responses to polymeric biomaterials.

  12. Effect of chemical composition on corneal tissue response to photopolymerized materials comprising 2-hydroxyethyl methacrylate and acrylic acid.

    PubMed

    Lai, Jui-Yang

    2014-01-01

    The purpose of this work was to investigate the relationship between the feed composition of 2-hydroxyethyl methacrylate (HEMA)/acrylic acid (AAc) and hydrogel material compatibility towards ocular anterior segment tissues, particularly the corneal endothelium. The monomer solutions of HEMA and AAc were mixed at varying volume ratios of 92:0, 87:5, 82:10, 77:15, and 72:20, and were subjected to UV irradiation. Then, the 7-mm-diameter membrane implants made from photopolymerized materials were placed into the ocular anterior chamber for 4days and assessed by biomicroscopic examinations, corneal thickness measurements, and quantitative real-time reverse transcription polymerase chain reaction analyses. The poly(HEMA-co-AAc) implants prepared from the solution mixture containing 0-10vol.% AAc displayed good biocompatibility. However, with increasing volume ratio of AAc and HEMA from 15:77 to 20:72, the enhanced inflammatory response, decreased endothelial cell density, and increased ocular score and corneal thickness were observed, probably due to the influence of surface charge of copolymer membranes. On the other hand, the ionic pump function of corneal endothelium exposed to photopolymerized membranes was examined by analyzing the Na(+),K(+)-ATPase alpha 1 subunit (ATP1A1) expression level. The presence of the implants having higher amount of AAc incorporated in the copolymers (i.e., 15.1 to 24.7μmol) and zeta potential (i.e., -38.6 to -56.5mV) may lead to abnormal transmembrane transport. It is concluded that the chemical composition of HEMA/AAc has an important influence on the corneal tissue responses to polymeric biomaterials.

  13. Protein-resistant polyurethane by sequential grafting of poly(2-hydroxyethyl methacrylate) and poly(oligo(ethylene glycol) methacrylate) via surface-initiated ATRP.

    PubMed

    Jin, Zhilin; Feng, Wei; Zhu, Shiping; Sheardown, Heather; Brash, John L

    2010-12-15

    Protein-resistant polyurethane (PU) surfaces were prepared by sequentially grafting poly(2-hydroxyethyl methacrylate) (poly(HEMA)) and poly(oligo(ethylene glycol) methacrylate) (poly(OEGMA)) via surface-initiated atom transfer radical polymerization (s-ATRP). The chain lengths of poly(HEMA) and poly(OEGMA) were regulated via the ratio of monomer to sacrificial initiator in solution. The surfaces were characterized by water contact angle and X-ray photoelectron spectroscopy (XPS). The protein resistant properties of the surfaces were assessed by single and binary adsorption experiments with fibrinogen (Fg), lysozyme (Lys), and lactalbumin (Lac). The adsorption of all three proteins on the sequentially grafted poly(HEMA)-poly(OEGMA) surfaces (PU/PH/PO) was greatly reduced compared with the unmodified PU. Adsorption decreased with increasing poly(OEGMA) chain length. On the PU/PH/PO surface with longest poly(OEGMA) chain length (∼100), the decrease in Lys adsorption was in the range of 95-98% and the decrease in Fg and Lac adsorption was >99% compared with the unmodified PU. Adsorption from binary protein solutions showed that the PU/PH/PO surfaces resisted these proteins more or less equally, that is, independent of protein size.

  14. N-acetyl cysteine mediates protection from 2-hydroxyethyl methacrylate induced apoptosis via nuclear factor kappa B-dependent and independent pathways: potential involvement of JNK.

    PubMed

    Paranjpe, Avina; Cacalano, Nicholas A; Hume, Wyatt R; Jewett, Anahid

    2009-04-01

    The mechanisms by which resin based materials induce adverse effects in patients have not been completely elucidated. Here we show that 2-hydroxyethyl methacrylate (HEMA) induces apoptotic cell death in oral keratinocytes. Functional loss and cell death induced by HEMA was significantly inhibited in the presence of N-acetyl cysteine (NAC) treatment. NAC also prevented HEMA mediated decrease in vascular endothelial growth factor secretion. The protective effect of NAC was partly related to its ability to induce NF-kappaB in the cells, since HEMA mediated inhibition of nuclear NF-kappaB expression and function was significantly blocked in the presence of NAC treatment. Moreover, blocking of nuclear translocation of NF-kappaB in oral keratinocytes sensitized these cells to HEMA mediated apoptosis. In addition, since NAC was capable of rescuing close to 50% of NF-kappaB knockdown cells from HEMA mediated cell death, there is, therefore, an NF-kappaB independent pathway of protection from HEMA mediated cell death by NAC. NAC mediated prevention of HEMA induced cell death in NF-kappaB knockdown cells was correlated with a decreased induction of c-Jun N-terminal kinase (JNK) activity since NAC inhibited HEMA mediated increase in JNK levels. Furthermore, the addition of a pharmacologic JNK inhibitor to HEMA treated cells prevented cell death and restored NF-kappaB knockdown cell function significantly. Therefore, NAC protects oral keratinocytes from the toxic effects of HEMA through NF-kappaB dependent and independent pathways. Moreover, our data suggest the potential involvement of JNK pathway in NAC mediated protection.

  15. Identification of covalent binding sites of ethyl 2-cyanoacrylate, methyl methacrylate and 2-hydroxyethyl methacrylate in human hemoglobin using LC/MS/MS techniques.

    PubMed

    Jeppsson, Marina C; Mörtstedt, Harriet; Ferrari, Giovanni; Jönsson, Bo A G; Lindh, Christian H

    2010-10-01

    Acrylates are used in vast quantities, for instance in paints, adhesive glues, molding. They are potent contact allergens and known to cause respiratory hypersensitivity and asthma. Here we study ethyl 2-cyanoacrylate (ECA), methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA). There are only limited possibilities to measure the exposure to acrylates, especially for biological monitoring. The aim of the present study was to investigate the chemical structures of adducts formed after reaction of hemoglobin (Hb) with ECA, MMA, and HEMA. This information may be used to identify adducted Hb peptides for biological monitoring of exposure to acrylates. Hb-conjugates with ECA, MMA, and HEMA were synthesized in vitro. The conjugates were digested by trypsin and pronase E. Adducted peptides were characterized and analyzed by liquid chromatography and nano electro spray/hybrid quadrupole time-of-flight mass spectrometry (MS) as well as tandem quadrupole MS. The search for the adducted peptides was facilitated by visualizing the MS data by different computer programs. The results showed that ECA binds covalently to cysteines at the 104 position in the α and the position 112 in the β-chains in Hb. MMA and HEMA bound to all the cysteines in both chains, Cys(104) in the α-chain and Cys(93) and 112 in the β-chain. The full-length spectra of in un-digested Hb confirmed this binding pattern. There was no reaction with N-acetyl-L-lysine at physiological pH. The adducted peptides were possible to measure using LC/MS/MS in selected reaction monitoring mode. These peptides may be used for biological monitoring of exposure to ECA, MMA and HEMA.

  16. Streptococcus mitis/human gingival fibroblasts co-culture: the best natural association in answer to the 2-hydroxyethyl methacrylate release.

    PubMed

    Di Giulio, Mara; D'Ercole, Simonetta; Zara, Susi; Cataldi, Amelia; Cellini, Luigina

    2012-02-01

    One of the major components of dental polymerized resin-based restorative materials is 2-hydroxyethyl methacrylate (HEMA) and its release in monomeric form interferes with the oral cavity environment. This study aimed to evaluate HEMA monomeric effects on the co-culture of Streptococcus mitis and human gingival fibroblasts (HGFs). Streptococcus mitis DS12 and S. mitis ATCC 6249 were co-cultivated with HGF in the presence of HEMA (3 mM), for 48 and 72 h; the amount of sessile and planktonic cells, as well as the prokaryotic and eukaryotic cell viability were analyzed in treated and untreated samples. The treatment of S. mitis/HGFs with HEMA did not produce significant effects on the bacterial adhesion and induced an increase in planktonic S. mitis ATCC 6249 population after 48 and 72 h. HEMA increased significantly the planktonic S. mitis ATCC 6249 viability when co-cultured with HGFs, while a cytotoxic effect on HGFs, without bacteria, was recorded. An increase of bacterial aggregation on HGFs was also detected with HEMA. Data obtained in this study suggest that HEMA exhibits a toxic effect mainly on eukaryotic cells and this effect can be modulated by co-cultivation with the S. mitis cells which, in the presence of the monomer, enhance their aggregation rate on HGFs.

  17. 2-hydroxylethyl methacrylate (HEMA), a tooth restoration component, exerts its genotoxic effects in human gingival fibroblasts trough methacrylic acid, an immediate product of its degradation.

    PubMed

    Szczepanska, Joanna; Poplawski, Tomasz; Synowiec, Ewelina; Pawlowska, Elzbieta; Chojnacki, Cezary J; Chojnacki, Jan; Blasiak, Janusz

    2012-02-01

    HEMA (2-hydroxyethyl methacrylate), a methacrylate commonly used in dentistry, was reported to induce genotoxic effects, but their mechanism is not fully understood. HEMA may be degraded by the oral cavity esterases or through mechanical stress following the chewing process. Methacrylic acid (MAA) is the primary product of HEMA degradation. In the present work we compared cytotoxic and genotoxic effects induced by HEMA and MAA in human gingival fibroblasts (HGFs). A 6-h exposure to HEMA or MAA induced a weak decrease in the viability of HGFs. Neither HEMA nor MAA induced strand breaks in the isolated plasmid DNA, but both compounds evoked DNA damage in HGFs, as evaluated by the alkaline comet assay. Oxidative modifications to the DNA bases were monitored by the DNA repair enzymes Endo III and Fpg. DNA damage induced by HEMA and MAA was not persistent and was removed during a 120 min repair incubation. Results from the neutral comet assay indicated that both compounds induced DNA double strand breaks (DSBs) and they were confirmed by the γ-H2AX assay. Both compounds induced apoptosis and perturbed the cell cycle. Therefore, methacrylic acid, a product of HEMA degradation, may be involved in its cytotoxic and genotoxic action.

  18. Role of thiol-complex formation in 2-hydroxyethyl- methacrylate-induced toxicity in vitro.

    PubMed

    Samuelsen, J T; Kopperud, H M; Holme, J A; Dragland, I S; Christensen, T; Dahl, J E

    2011-02-01

    Methacrylate monomers that are found to leach from cured resin-based dental materials induce biological effects in vitro. The underlying mechanisms have not been fully elucidated although involvement of increased cellular reactive oxygen species (ROS) and DNA-damage has been suggested. In this in vitro study we have elucidated the impact of a commonly used methacrylate monomer, HEMA, on the level and oxidation state of cellular glutathione, intracellular ROS level, as well as the formation of complex between HEMA and glutathione. HEMA exposure rapidly led to increased level of ROS and reduced level of GSH (reduced form of glutathione). Antioxidants effectively counteracted the ROS increase, but had no effect on the GSH depletion. No change in glutathione-disulphide (GSSG; oxidized form of glutathione) concentration was detected in the HEMA treated cells, showing that oxidation of glutathione was not responsible for the reduced GSH concentration. Further we demonstrated spontaneous formation of a complex between HEMA and GSH. In conclusion, we showed that exposure to HEMA led to drop in cellular glutathione level probably caused by complex formation with HEMA. A similar covalent binding of HEMA to macromolecules combined with increased level of cellular ROS due to lower levels of GSH is suggested to be important factors triggering the toxic response.

  19. Poly(2-hydroxyethyl methacrylate) (PHEMA) grafted polyethylene/polypropylene (PE/PP) nonwoven fabric by γ-initiation: Synthesis, characterization and benefits of RAFT mediation

    NASA Astrophysics Data System (ADS)

    Kodama, Yasko; Barsbay, Murat; Güven, Olgun

    2014-12-01

    Polyethylene/polypropylene (PE/PP) nonwoven fabrics were functionalized by γ-initiated RAFT mediated grafting of 2-hydroxyethyl methacrylate (HEMA), and the characterization of the grafted samples was carried out using various techniques. FTIR and XPS analysis showed an increase in the oxygenated content till a certain degree of grafting. The results implied a grafting process following the concept of ‘front mechanism’. The initial grafting occurred on the topmost surface layer, and then moved further into the bulk of the polymer matrix. Reversible addition-fragmentation chain transfer (RAFT) mediated grafting yielded a better controlled grafting when compared to those obtained in conventional grafting.

  20. Photophysical, photochemical and laser behavior of some diolefinic laser dyes in sol-gel and methyl methacrylate/2-hydroxyethyl methacrylate copolymer matrices

    NASA Astrophysics Data System (ADS)

    Sakr, Mahmoud A. S.; Abdel Gawad, El-Sayed A.; Abou Kana, Maram T. H.; Ebeid, El-Zeiny M.

    2015-08-01

    The photophysical properties such as singlet absorption, molar absorptivity, fluorescence spectra, dipole moment, fluorescence quantum yields, fluorescence lifetimes and laser activity of 1,4-bis (β-Pyridyl-2-Vinyl) Benzene (P2VB), 2,5-distyryl-pyrazine (DSP) and 1,4-bis(2-methylstyryl)benzene(MSB) diolefineic laser dyes have been measured in different restricted hosts. (P2VB), (DSP) and (MSB) are embedded in transparent sol-gel glass and a copolymer of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) media. The absorption and fluorescence properties of these laser dyes in sol-gel glass matrices are compared with their respective properties in copolymer host. The photostability of these laser dyes in sol-gel glass and (MMA/HEMA) copolymer samples are measured in terms of half-life method (using nitrogen laser 337.1 nm in pumping), as the number of pulses necessary to reduce the dye laser intensity to 50% of its original value. The gel laser materials show improved photostability upon pumping by nitrogen laser compared with those in organic polymeric host matrix.

  1. Study on chemical, UV and gamma radiation-induced grafting of 2-hydroxyethyl methacrylate onto chitosan

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Botelho, M. L.; Leal, J. P.; Gil, M. H.

    2005-04-01

    In the present study, 2-hydroxyethyl methacrylate has been grafted onto chitosan by using either chemical initiation, or photo-induction or gamma radiation-induced polymerisation, all under heterogeneous conditions. The evidence of grafting was provided by Fourier transform infrared spectroscopy and thermal analysis. The results concerning the effect of initiator concentration, initial monomer concentration and dose rate influencing on the yield of grafting reactions are presented. These suggest that gamma irradiation is the method that leads to higher yields of grafting.

  2. Release of Water Soluble Drugs from Dynamically Swelling POLY(2-HYDROXYETHYL Methacrylate - CO - Methacrylic Acid) Hydrogels.

    NASA Astrophysics Data System (ADS)

    Kou, Jim Hwai-Cher

    In this study, ionizable copolymers of HEMA and methacrylic acid (MA) are investigated for their potential use in developing pH dependent oral delivery systems. Because of the MA units, these gels swell extensively at high pH. Since solute diffusion in the hydrophilic polymers depends highly on the water content of the matrix, it is anticipated that the release rate will be modulated by this pH induced swelling. From a practical point of view, the advantage of the present system is that one can minimize drug loss in the stomach and achieve a programmed release in intestine. This approach is expected to improve delivery of acid labile drugs or drugs that cause severe gastrointestinal side effects. This work mainly focuses on the basic understanding of the mechanism involved in drug release from the poly(HEMA -co- MA) gels, especially under dynamic swelling conditions. Equilibrium swelling is first characterized since water content is the major determinant of transport properties in these gels. Phenylpropanolamine (PPA) is chosen as the model drug for the release study and its diffusion characteristics in the gel matrix determined. The data obtained show that the PPA diffusivity follows the free volume theory of Yasuda, which explains the accelerating effect of swelling on drug release. A mathematical model based on a diffusion mechanism has been developed to describe PPA release from the swelling gels. Based on this model, several significant conclusions can be drawn. First, the release rate can be modulated by the aspect ratio of the cylindrical geometry, and this has a practical implication in dosage form design. Second, the release rate can be lowered quite considerably if the dimensional increase due to swelling is significant. Consequently, it is the balance between the drug diffusivity increase and the gel dimensional growth that determines the release rate from the swelling matrix. Third, quasi-steady release kinetics, which are characteristic of swelling

  3. The dental monomer hydroxyethyl methacrylate (HEMA) counteracts lipopolysaccharide-induced IL-1β release-Possible role of glutathione.

    PubMed

    Bolling, Anette Kocbach; Solhaug, Anita; Morisbak, Else; Holme, Jørn A; Samuelsen, Jan Tore

    2017-02-07

    Methacrylate monomers, like 2-hydroxyethyl methacrylate (HEMA), are common components of resin based dental materials. Leakage of unpolymerized monomers after placement and curing leads to human exposure. HEMA is known to inhibit lipopolysaccharide (LPS) induced cytokine release. In this study we explore a possible role of the antioxidant glutathione (GSH) in this effect. In the RAW 264.7 murine macrophage cell line, HEMA (<2mM) did not induce cell death, but reduced cellular GSH levels, increased cellular ROS and decreased the IL-1β release from LPS-stimulated cells. Moreover, the IL-1β mRNA levels were reduced after 3-6h exposure, suggesting transcriptional effects of HEMA. The GSH modulators butylsulfoximine (BSO; inhibitor of GSH synthesis) and 2-oxothiazolidine-4-carboxylate (OTC; Cysteine precursor) caused a decrease and increase in the LPS-induced IL-1β release, respectively, suggesting a role for GSH in negative regulation of LPS-induced IL-1β release. However, the magnitude and dynamics of the effects of HEMA and BSO on LPS-induced IL-1β release and GSH depletion differed considerably. Thus, GSH depletion alone could not explain the strong attenuation of LPS-induced IL-1β release caused by HEMA. Formation of HEMA-protein conjugates due to the thiol reactivity of HEMA emerges as a likely candidate for the molecular mechanism accounting for this effect.

  4. Macroporous hydrogels based on 2-hydroxyethyl methacrylate. Part 6: 3D hydrogels with positive and negative surface charges and polyelectrolyte complexes in spinal cord injury repair.

    PubMed

    Hejcl, A; Lesný, P; Prádný, M; Sedý, J; Zámecník, J; Jendelová, P; Michálek, J; Syková, E

    2009-07-01

    Macroporous hydrogels are artificial biomaterials commonly used in tissue engineering, including central nervous system (CNS) repair. Their physical properties may be modified to improve their adhesion properties and promote tissue regeneration. We implanted four types of hydrogels based on 2-hydroxyethyl methacrylate (HEMA) with different surface charges inside a spinal cord hemisection cavity at the Th8 level in rats. The spinal cords were processed 1 and 6 months after implantation and histologically evaluated. Connective tissue deposition was most abundant in the hydrogels with positively-charged functional groups. Axonal regeneration was promoted in hydrogels carrying charged functional groups; hydrogels with positively charged functional groups showed increased axonal ingrowth into the central parts of the implant. Few astrocytes grew into the hydrogels. Our study shows that HEMA-based hydrogels carrying charged functional groups improve axonal ingrowth inside the implants compared to implants without any charge. Further, positively charged functional groups promote connective tissue infiltration and extended axonal regeneration inside a hydrogel bridge.

  5. Surface functionalization of graphene oxide with poly(2-hydroxyethyl methacrylate)- graft-poly(ɛ-caprolactone) and its electrospun nanofibers with gelatin

    NASA Astrophysics Data System (ADS)

    Massoumi, Bakhshali; Ghandomi, Fereshteh; Abbasian, Mojtaba; Eskandani, Morteza; Jaymand, Mehdi

    2016-12-01

    This article describes covalent functionalization of graphene oxide (GO) with poly(2-hydroxyethyl methacrylate)- graft-poly(ɛ-caprolactone) [P(HEMA- g-CL)] via `living' polymerization techniques and preparation of its electrospun nanofibers with gelatin. For this purpose, the GO was synthesized by oxidizing pristine graphite powder and then acetyl chloride was incorporated into the GO to afford an atom transfer radical polymerization (ATRP) macroinitiator (GO-Cl). The synthesized macroinitiator was employed for HEMA polymerization via ATRP technique to produce GO- g-PHEMA. Afterward, CL was graft copolymerized from the hydroxyl groups of the PHEMA via ring-opening polymerization approach to afford GO- g-[P(HEMA- g-CL)] nanocomposite. The solutions of the GO- g-[P(HEMA- g-CL)] and gelatin were electrospun to fabricate uniform, conductive, and biocompatible nanofibers. The morphology, in vitro degradability, biocompatibility, hydrophilicity, and conductivity of the GO- g-[P(HEMA- g-CL)]/gelatin electrospun nanofibers were investigated. It is expected that the prepared nanofibers find application as a scaffolding biomaterial for regenerative medicine, mainly due to their biocompatibility, degradability, and electrical conductivity.

  6. Deposition of plasma-polymerized hydroxyethyl methacrylate (HEMA) on silicon in presence of argon plasma

    NASA Astrophysics Data System (ADS)

    Bodas, Dhananjay S.; Desai, Shrojal M.; Gangal, S. A.

    2005-05-01

    2-hydroxyethyl methacrylate (HEMA) has been deposited onto the surface of silicon substrate (thickness = 500 μm) using plasma polymerization technique. Polymerization process was carried out in an in-house developed inductively coupled plasma polymerization setup. The depositions were carried out using RF power supply (13.56 MHz) at power of 75 W for 10 and 40 min. The RF supply was coupled to the inductance through a matching network. The effect of plasma polymerization (surface grafting) on the degree of surface modification has been investigated. The chemical changes on the polymer backbone are followed from the results of Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS), which show the peaks corresponding to the functional groups of the HEMA polymerized onto the silicon surface. The morphology of the modified surfaces has also been investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The hydrophilicity was determined from the water contact angle measurements.

  7. Solid-state dye lasers based on copolymers of 2-hydroxyethyl methacrylate and methyl methacrylate doped with rhodamine 6G

    NASA Astrophysics Data System (ADS)

    Costela, A.; Florido, F.; Garcia-Moreno, I.; Duchowicz, R.; Amat-Guerri, F.; Figuera, J. M.; Sastre, R.

    1995-04-01

    Rhodamine 6G has been dissolved in copolymers of 2-HydroxyEthyl MethAcrylate (HEMA) and Methyl MethAcrylate (MMA) and the resulting solid-state solutions have been pumped at 337 nm and 532 nm. Lasing efficiencies similar to those found in ethanol solution have been obtained with a 1:1 vol/vol HEMA: MMA copolymer matrix, and lifetimes of ca. 10 000 (337 nm pumping) and ca. 75 000 (532 nm pumping) pulses at repetition rates up to 15 Hz and 10 Hz, respectively, have been demonstrated.

  8. Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

    PubMed Central

    2012-01-01

    Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II). PMID:23369255

  9. Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies.

    PubMed

    Moradi, Omid; Mirza, Behrooz; Norouzi, Mehdi; Fakhri, Ali

    2012-12-22

    Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293-323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II).

  10. Effects of poly(2-hydroxyethyl methacrylate) and poly(vinyl-pyrrolidone) hydrogel implants on myopic and normal chick sclera

    PubMed Central

    Su, James; Iomdina, Elena; Tarutta, Elena; Ward, Brian; Song, Jie; Wildsoet, Christine F.

    2008-01-01

    There has been generally little attention paid to the utilization of biomaterials as an anti-myopia treatment. The purpose of this study was to investigate whether polymeric hydrogels, either implanted or injected adjacent to the outer scleral surface, slow ocular elongation. White Leghorn (gallus gallus domesticus) chicks were used at 2 weeks of age. Chicks had either (1) strip of poly(2-hydroxyethyl methacrylate) (pHEMA) implanted monocularly against the outer sclera at the posterior pole, or (2) an in situ polymerizing gel [main ingredient: poly(vinyl-pyrrolidone) (PVP)] injected monocularly at the same location. Some of the eyes injected with the polymer were fitted with a diffuser or a −10D lens. In each experiment, ocular lengths were measured at regular intervals by high frequency A-scan ultrasonography, and chicks were sacrificed for histology at staged intervals. No in vivo signs of either orbital or ocular inflammation were observed. The pHEMA implant significantly increased scleral thickness by the third week, and the implant became encapsulated with fibrous tissue. The PVP-injected eyes left otherwise untreated, showed a significant increase in scleral thickness, due to increased chondrocyte proliferation and extracellular matrix deposition. However, there was no effect of the PVP injection on ocular elongation. In eyes wearing optical devices, there was no effect on either scleral thickness or ocular elongation. These results represent “proof of principle” that scleral growth can be manipulated without adverse inflammatory responses. However, since neither approach slowed ocular elongation, additional factors must influence scleral surface area expansion in the avian eye. PMID:19109950

  11. Effect of monomer mixture composition on structure and chromatographic properties of poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monolithic rod columns for separation of small molecules.

    PubMed

    Smirnov, Konstantin N; Dyatchkov, Ivan A; Telnov, Maxim V; Pirogov, Andrey V; Shpigun, Oleg A

    2011-07-29

    Porous poly(divinylbenzene-co-ethylvinylbenzene-co-2-hydroxyethyl methacrylate) monoliths were synthesized via thermally initiated free-radical polymerization in confines of surface-vinylized glass columns (150 mm × 3 mm i.d.) and applied to the reversed-phase separation of low-molecular-weight aromatic compounds. In order to compensate for the polymer shrinkage during the synthesis and prevent the monolith from detachment from the column wall, polymerization was conducted under nitrogen pressure. The reaction proceeded at 60°C for 22 h. 2,2'-Azo-bis-isobutironitrile was used as the initiator and 1-dodecanol was used as the porogen. A series of monoliths with different monomer ratios were obtained. All the monoliths had high specific surface areas ranging from 370 to 490 m(2)/g. In the studied range of monomer mixture compositions, the mechanical stability of the stationary phase in water/acetonitrile eluents was found to be high enough and practically insensitive to the fraction of 2-hydroxyethyl methacrylate (HEMA). Increasing the molar fraction of HEMA from 10.5% to 14.7% resulted in the decrease of column permeability by two orders of magnitude (from 1.1×10(-12) to 1.8×10(-14) m(2)) and led to weaker retention of alkylbenzenes. The higher HEMA content was shown to reduce the plate height of the columns in the separation of small molecules from 160-490 μm to 40-76 μm. This was attributed mainly to the decrease of the domain size of the monoliths leading to lower eddy dispersion and mass transfer resistance in the column.

  12. Preparation and characterization of pH-sensitive and antifouling poly(vinylidene fluoride) microfiltration membranes blended with poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid).

    PubMed

    Ju, Junping; Wang, Chao; Wang, Tingmei; Wang, Qihua

    2014-11-15

    Functional terpolymer of poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid) (P(MMA-HEMA-AA)) was synthesized via a radical polymerization method. The terpolymer could be directly blended with poly(vinylidene fluoride) (PVDF) to prepare the microfiltration (MF) membranes via phase separate process. The synthesized polymers were characterized by Fourier transform infrared (FTIR), the nuclear magnetic resonance proton spectra ((1)H NMR). The membrane had the typical asymmetric structure and the hydrophilic side chains tended to aggregate on the membrane surface. The surface enrichment of amphiphilic copolymer and morphology of MF membranes were characterized by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). The contact angle (CA) and water uptake were also tested to assess the hydrophilicity and wetting characteristics of the polymer surface. The water filtration properties were measured. It was found the modified membranes showed excellent pH-sensitivity and pH-reversibility behavior. Furthermore, the hydrophilicity of the blended membranes increased, and the membranes showed good protein antifouling property.

  13. Host reaction to poly(2-hydroxyethyl methacrylate) scaffolds in a small spinal cord injury model.

    PubMed

    Li, Hong Ying; Führmann, Tobias; Zhou, Yue; Dalton, Paul D

    2013-08-01

    Tissue engineered scaffolds and matrices have been investigated over the past decade for their potential in spinal cord repair. They provide a 3-D substrate that can be permissive for nerve regeneration yet have other roles including neuroprotection, altering the inflammatory cascade and mechanically stabilizing spinal cord tissue after injury. In this study we investigated very small lesions (approx. 0.25 μL in volume) of the dorsal column into which a phase-separated poly(2-hydroxyethyl methacrylate) hydrogel scaffold is implanted. Using fluorescent immunohistochemistry to quantify glial scarring, the poly(2-hydroxyethyl methacrylate) scaffold group showed reduced intensity compared to lesion controls for GFAP and the chondroitin sulfate proteoglycan neurocan after 6 days. However, the scaffold and tissue was also pushed dorsally after 6 days while the scaffold was not integrated into the spinal cord after 28 days. Overall, this small-lesion spinal cord injury model provided information on the host tissue reaction of a TE scaffold while reducing animal discomfort and care.

  14. Synthesis and Examination of Nanocomposites Based on Poly(2-hydroxyethyl methacrylate) for Medicinal Use.

    PubMed

    Kukolevska, Olena S; Gerashchenko, Igor I; Borysenko, Mykola V; Pakhlov, Evgenii M; Machovsky, Michal; Yushchenko, Tetyana I

    2017-12-01

    Preparation of poly(2-hydroxyethyl methacrylate) (PHEMA) based nanocomposites using different approaches such as synthesis with water as the porogen, filling of polymer matrix by silica and formation of interpenetrating polymer networks with polyurethane was demonstrated. Incorporation of various biologically active compounds (BAC) such as metronidazole, decamethoxin, zinc sulphate, silver nitrate or amino acids glycine and tryptophan into nanocomposites was achieved. BAC were introduced into the polymer matrix either (1) directly, or (2) with a solution of colloidal silica, or (3) through immobilization on silica (sol-densil). Morphology of prepared materials was investigated by laser scanning microscopy and low-vacuum scanning electron microscopy. In vacuum freeze-drying, prior imaging was proposed for improving visualization of the porous structure of composites. The interaction between PHEMA matrix and silica filler was investigated by IR spectroscopy. Adsorption of 2-hydroxyethyl methacrylate and BAC from aqueous solution on the silica surface was also examined. Phase composition and thermal stability of composites were studied by the differential thermogravimetry/differential thermal analysis. Release of BAC into water medium from prepared composites were shown to depend on the synthetic method and differed significantly. Obtained PHEMA-base materials which are characterized by controlled release of BAC have a strong potential for application in manufacturing of different surgical devices like implants, catheters and drainages.

  15. Synthesis and Examination of Nanocomposites Based on Poly(2-hydroxyethyl methacrylate) for Medicinal Use

    NASA Astrophysics Data System (ADS)

    Kukolevska, Olena S.; Gerashchenko, Igor I.; Borysenko, Mykola V.; Pakhlov, Evgenii M.; Machovsky, Michal; Yushchenko, Tetyana I.

    2017-02-01

    Preparation of poly(2-hydroxyethyl methacrylate) (PHEMA) based nanocomposites using different approaches such as synthesis with water as the porogen, filling of polymer matrix by silica and formation of interpenetrating polymer networks with polyurethane was demonstrated. Incorporation of various biologically active compounds (BAC) such as metronidazole, decamethoxin, zinc sulphate, silver nitrate or amino acids glycine and tryptophan into nanocomposites was achieved. BAC were introduced into the polymer matrix either (1) directly, or (2) with a solution of colloidal silica, or (3) through immobilization on silica (sol-densil). Morphology of prepared materials was investigated by laser scanning microscopy and low-vacuum scanning electron microscopy. In vacuum freeze-drying, prior imaging was proposed for improving visualization of the porous structure of composites. The interaction between PHEMA matrix and silica filler was investigated by IR spectroscopy. Adsorption of 2-hydroxyethyl methacrylate and BAC from aqueous solution on the silica surface was also examined. Phase composition and thermal stability of composites were studied by the differential thermogravimetry/differential thermal analysis. Release of BAC into water medium from prepared composites were shown to depend on the synthetic method and differed significantly. Obtained PHEMA-base materials which are characterized by controlled release of BAC have a strong potential for application in manufacturing of different surgical devices like implants, catheters and drainages.

  16. Phase separation kinetics and morphology induced by photopolymerization of 2-hydroxyehyl methacrylate (HEMA) in poly(ethyl acrylate)/HEMA mixtures

    NASA Astrophysics Data System (ADS)

    Van-Pham, Dan-Thuy; Tran-Cong-Miyata, Qui

    2013-03-01

    Morphology and phase separation kinetics induced by polymerization of 2-hydroxyethyl methacrylate (HEMA) in a HEMA/poly(ethyl acrylate) (PEA) mixture were observed by laser scanning confocal microscope in the presence of lucirin TPO used as an initiator. The results were analyzed by 2D-Fourier transform (2D-FFT). The photopolymerization is driven by irradiation with visible light λ = 405 nm. The mixture exhibits the Trommsdorff-Norrish effect which is responsible for a drastic increase in the reaction rate during the irradiation process. The concentration fluctuations and the increase in the viscosity of the medium play an important role in promoting the reaction yield. PHEMA droplets were found to develop in the rhodamine-B-labeled poly(ethyl acrylate) (PEA-Rh) continuous matrix. The characteristic length of the morphology increases with increasing irradiation intensity, revealing the tool to control the morphology by varying the light intensity.

  17. Poly(2-hydroxyethyl methacrylate)-b-poly(L-Lysine) cationic hybrid materials for non-viral gene delivery in NIH 3T3 mouse embryonic fibroblasts.

    PubMed

    Johnson, Renjith P; Uthaman, Saji; John, Johnson V; Heo, Min Seon; Park, In Kyu; Suh, Hongsuk; Kim, Il

    2014-09-01

    In order to develop efficient and nontoxic gene delivery vectors, a series of biocompatible block copolymers, poly[(2-hydroxyethyl methacrylate)40 -block-(L-lysine)n ] (n = 40, 80, 120, 150), are prepared by combining an atom transfer radical polymerization of 2-hydroxyethyl methacrylate with a ring-opening polymerization of N(ϵ) -(carbobenzoxy)-L-lysine N-carboxyanhydride. The block copolymers are successfully condensed with plasmid DNA (pDNA) into nanosized (<200 nm) polyplexes. As a representative sample, p(HEMA)40 -b-p(lys)150 is utilized to confirm the effective cellular and nuclear uptake of pDNA. The polymer/pDNA polyplexes exhibit very low cytotoxicity and enhanced transfection activity by being easily taken up into mouse embryonic fibroblast cell line (NIH 3T3). Thus, the chimeric block copolymers provide a means for developing versatile nonviral gene vectors harboring the ideal requirements of low cytotoxicity, good stability, and high transfection efficiency for gene therapy.

  18. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  19. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  20. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  1. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  2. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  3. A New Route for High-Purity Organic Materials: High-Pressure-Ramp-Induced Ultrafast Polymerization of 2-(Hydroxyethyl)Methacrylate

    PubMed Central

    Evlyukhin, E.; Museur, L.; Traore, M.; Perruchot, C.; Zerr, A.; Kanaev, A.

    2015-01-01

    The synthesis of highly biocompatible polymers is important for modern biotechnologies and medicine. Here, we report a unique process based on a two-step high-pressure ramp (HPR) for the ultrafast and efficient bulk polymerization of 2-(hydroxyethyl)methacrylate (HEMA) at room temperature without photo- and thermal activation or addition of initiator. The HEMA monomers are first activated during the compression step but their reactivity is hindered by the dense glass-like environment. The rapid polymerization occurs in only the second step upon decompression to the liquid state. The conversion yield was found to exceed 90% in the recovered samples. The gel permeation chromatography evidences the overriding role of HEMA2•• biradicals in the polymerization mechanism. The HPR process extends the application field of HP-induced polymerization, beyond the family of crystallized monomers considered up today. It is also an appealing alternative to typical photo- or thermal activation, allowing the efficient synthesis of highly pure organic materials. PMID:26671290

  4. A New Route for High-Purity Organic Materials: High-Pressure-Ramp-Induced Ultrafast Polymerization of 2-(Hydroxyethyl)Methacrylate

    NASA Astrophysics Data System (ADS)

    Evlyukhin, E.; Museur, L.; Traore, M.; Perruchot, C.; Zerr, A.; Kanaev, A.

    2015-12-01

    The synthesis of highly biocompatible polymers is important for modern biotechnologies and medicine. Here, we report a unique process based on a two-step high-pressure ramp (HPR) for the ultrafast and efficient bulk polymerization of 2-(hydroxyethyl)methacrylate (HEMA) at room temperature without photo- and thermal activation or addition of initiator. The HEMA monomers are first activated during the compression step but their reactivity is hindered by the dense glass-like environment. The rapid polymerization occurs in only the second step upon decompression to the liquid state. The conversion yield was found to exceed 90% in the recovered samples. The gel permeation chromatography evidences the overriding role of HEMA2•• biradicals in the polymerization mechanism. The HPR process extends the application field of HP-induced polymerization, beyond the family of crystallized monomers considered up today. It is also an appealing alternative to typical photo- or thermal activation, allowing the efficient synthesis of highly pure organic materials.

  5. A New Route for High-Purity Organic Materials: High-Pressure-Ramp-Induced Ultrafast Polymerization of 2-(Hydroxyethyl)Methacrylate.

    PubMed

    Evlyukhin, E; Museur, L; Traore, M; Perruchot, C; Zerr, A; Kanaev, A

    2015-12-16

    The synthesis of highly biocompatible polymers is important for modern biotechnologies and medicine. Here, we report a unique process based on a two-step high-pressure ramp (HPR) for the ultrafast and efficient bulk polymerization of 2-(hydroxyethyl)methacrylate (HEMA) at room temperature without photo- and thermal activation or addition of initiator. The HEMA monomers are first activated during the compression step but their reactivity is hindered by the dense glass-like environment. The rapid polymerization occurs in only the second step upon decompression to the liquid state. The conversion yield was found to exceed 90% in the recovered samples. The gel permeation chromatography evidences the overriding role of HEMA2(••) biradicals in the polymerization mechanism. The HPR process extends the application field of HP-induced polymerization, beyond the family of crystallized monomers considered up today. It is also an appealing alternative to typical photo- or thermal activation, allowing the efficient synthesis of highly pure organic materials.

  6. Functional polymeric microspheres based on 2-hydroxyethyl methacrylate for immunochemical studies

    NASA Technical Reports Server (NTRS)

    Rembaum, A.; Yen, S. P. S.; Cheong, E.; Wallace, S.; Molday, R. S.; Gordon, I. L.; Dreyer, W. J.

    1976-01-01

    Co gamma irradiation of 2-hydroxyethyl methacrylate in the presence or in the absence of other acrylic monomers was found to constitute an effective technique for the synthesis of hydrophilic functional microspheres in the size range of approximately 0.3 to 3 microns in diameter. The effect of monomer concentration, steric stabilization, and electrostatic interaction on the particle size was investigated. Experimental conditions were determined to obtain desired particle sizes of relatively narrow distribution. It was shown that particles may be formed without intermediate micelles, i.e., by homogeneous nucleation, and the rate of particle formation is affected primarily by the rate of particle coalescence in the initial stages of the reaction. When covalently bound to antibodies these microspheres were successfully used to label murine and human lymphocytes.

  7. The use of new surface-modified poly(2-hydroxyethyl methacrylate) hydrogels in tissue engineering: treatment of the surface with fibronectin subunits versus Ac-CGGASIKVAVS-OH, cysteine, and 2-mercaptoethanol modification.

    PubMed

    Kubinová, Šárka; Horák, Daniel; Vaněček, Václav; Plichta, Zdeněk; Proks, Vladimír; Syková, Eva

    2014-07-01

    Superporous poly(2-hydroxyethyl methacrylate) is successfully used as a scaffold material for tissue engineering; however, it lacks functional groups that support cell adhesion. The objective of this study was to investigate the cell-adhesive properties of biomimetic ligands, such as laminin-derived Ac-CGGASIKVAVS-OH (SIKVAV) peptide and fibronectin subunits (Fn), as well as small molecules exemplified by 2-mercaptoethanol (ME) and cysteine (Cys), immobilized on a copolymer of 2-hydroxyethyl methacrylate (HEMA) with 2-aminoethyl methacrylate (AEMA) by a maleimide-thiol coupling reaction. The maleimide group was introduced to the P(HEMA-AEMA) hydrogels by the reaction of their amino groups with N-γ-maleimidobutyryl-oxysuccinimide ester (GMBS). Mesenchymal stem cells (MSCs) were used to investigate the cell adhesive properties of the modified hydrogels. A significantly larger area of cell growth as well as a higher cell density were found on Fn- and SIKVAV-modified hydrogels when compared to the ME- and Cys-modified supports or neat P(HEMA-AEMA). Moreover, Fn-modification strongly stimulated cell proliferation. The ability of MSCs to differentiate into adipocytes and osteoblasts was maintained on both Fn- and SIKVAV-modifications, but it was reduced on ME-modified hydrogels and neat P(HEMA-AEMA). The results show that the immobilization of SIKVAV and Fn-subunits onto superporous P(HEMA-AEMA) hydrogels via a GMBS coupling reaction improves cell adhesive properties. The high proliferative activity observed on Fn-modified hydrogels suggests that the immobilized Fn-subunits maintain their bioactivity and thus represent a promising tool for application in tissue engineering.

  8. Radiation-induced synthesis and swelling properties of p(2-hydroxyethyl methacrylate/itaconic acid/oligo (ethylene glycol) acrylate) terpolymeric hydrogels

    NASA Astrophysics Data System (ADS)

    Micic, M.; Stamenic, D.; Suljovrujic, E.

    2012-09-01

    Since it is presumed that by incorporation of pH-responsive (IA) and temperature-responsive (OEGA) co-monomers, it is possible to prepare P(HEMA/IA/OEGA) hydrogels with dual (pH and thermo) responsiveness, the main purpose of our study is to investigate the influence of different mole fractions of IA and especially OEGA on the diversity of the swelling properties of the obtained hydrogels. For that reason, a series of terpolymeric hydrogels with different mole ratios of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and oligo(ethylene glycol) acrylates (OEGA) was synthesised by gamma radiation. The obtained hydrogels were characterised by swelling studies in the wide pH (2.2-9.0) and temperature range (20-70 °C), confirming dual (pH and thermo) responsiveness and a large variation in the swelling capability. It was observed that the equilibrium swelling of P(HEMA/IA/OEGA) hydrogels, for a constant amount of IA, increased progressively with an increase in OEGA share. On the other hand, the dissociation of carboxyl groups from IA occurs at pH>4; therefore, small mole fractions of IA render good pH sensitivity and a large increase in the swelling capacity of these hydrogels at higher pH values. Additional characterisation of structure and properties was conducted by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and mechanical measurements, confirming that the inherent properties of P(HEMA/IA/OEGA) hydrogels can be significantly tuned by variation in their composition. According to all presented, it seems that the obtained hydrogels can be a beneficial synergetic combination for controlled delivery of bioactive molecules such as drugs, peptides, proteins, etc.

  9. Prostate cancer xenografts engineered from 3D precision-porous poly(2-hydroxyethyl methacrylate) hydrogels as models for tumorigenesis and dormancy escape

    PubMed Central

    Long, Thomas J.; Sprenger, Cynthia C.; Plymate, Stephen R.; Ratner, Buddy D.

    2014-01-01

    Synthetic biomaterial scaffolds show promise for in vitro and in vivo 3D cancer models. Tumors engineered in biomaterial scaffolds have shown evidence of being more physiologically relevant than some traditional preclinical model systems, and synthetic biomaterials provide the added benefit of defined and consistent microenvironmental control. Here, we examine sphere-templated poly(2-hydroxyethyl methacrylate) (pHEMA) scaffolds as the basis for engineering xenografts from multiple human prostate cancer cell lines. pHEMA scaffolds seeded and pre-cultured with tumorigenic M12 cells prior to implantation generated tumors in athymic nude mice, demonstrating the ability of the scaffolds to be used as a synthetic vehicle for xenograft generation. pHEMA scaffolds seeded with LNCaP C4-2 cells, which require Matrigel or stromal cell support for tumor formation, were poorly tumorigenic up to twelve weeks after implantation even when Matrigel was infused into the scaffold, demonstrating a lack of necessary pro-tumorigenic signaling within the scaffolds. Finally, M12mac25 cells, which are ordinarily rendered non-tumorigenic through the expression of the tumor suppressor insulin-like growth factor binding protein 7 (IGFBP7), displayed a tumorigenic response when implanted within porous pHEMA scaffolds. These M12mac25 tumors showed a significantly higher macrophage infiltration within the scaffolds driven by the foreign body response to the materials. These findings show the potential for this biomaterials-based model system to be used in the study of prostate cancer tumorigenesis and dormancy escape. PMID:24942815

  10. Raman spectroscopy of 2-hydroxyethyl methacrylate-acrylamide copolymer using gamma irradiation for crosslinking

    SciTech Connect

    Goheen, Steven C.; Saunders, Rachel M.; Davis, Rachel M.; Harvey, Scott D.; Olsen, Peter C.

    2006-02-18

    A copolymer hydrogel was made by mixing acrylamide and 2-hydroxyethyl methacrylate monomers in water and polymerizing with gamma irradiation. The progress of polymerization and the vibrational structure of the hydrogel was examined using Raman spectroscopy. Raman spectra indicated that the co-polymer has a molecular structure different from polyacrylamide or the individual monomers. The Raman data also indicate the presence of crosslinking at the C=O, NH2 and OH side chains. The spectra further suggest the continuous lengthening of the backbone of the polymers with increasing gamma dose. This is shown as the increase in C-C modes as C=C vibrations decrease. Raman spectra changed most dramatically as the monomer mixture became a gel at a dose of approximately 320 Gy. Spectral differences were subtler with doses exceeding 640 Gy, although chain lengthening continued beyond 1500 Gy. Potential applications of the copolymer hydrogel include reconstructive tissue as well as a standard material for radiation protection dosimetry. Results are discussed in relation to other potential applications of this polymer and dose-dependent changes in the Raman spectrum.

  11. Pentablock copolymers of poly(ethylene glycol), poly((2-dimethyl amino)ethyl methacrylate) and poly(2-hydroxyethyl methacrylate) from consecutive atom transfer radical polymerizations for non-viral gene delivery.

    PubMed

    Xu, Fu-Jian; Li, Hongzhe; Li, Jun; Zhang, Zhongxing; Kang, En-Tang; Neoh, Koon-Gee

    2008-07-01

    Well-defined pentablock copolymers (PBPs) of P(HEMA)-b-P(DMAEMA)-b-PEG-b-P(DMAEMA)-b-P(HEMA) (in which PEG=poly(ethylene glycol), P(DMAEMA)=poly((2-dimethyl amino)ethyl methacrylate), and P(HEMA)=poly(2-hydroxyethyl methacrylate)), with different block lengths of P(DMAEMA), for non-viral gene delivery were prepared via consecutive atom transfer radical polymerizations (ATRPs) from the same di-2-bromoisobutyryl-terminated PEG (Br-PEG-Br) center block. The PBPs demonstrate good ability to condense plasmid DNA (pDNA) into 100-160 nm size nanoparticles with positive zeta potentials of 25-35 mV at PBPs/pDNA weight ratios of 5-25. The PBPs exhibit very low in vitro cytotoxicity and excellent gene transfection efficiency in HEK293 and COS7 cells. In particular, the transfection efficiencies of all the PBPs in HEK293 cells are comparable to, or higher than those of polyethylenimine (PEI, 25 kDa) at most weight ratios. The ability of the copolymers to condense plasmid DNA and the transfection efficiency of the resulting complexes are dependent on the chain length of P(DMAEMA) blocks. In addition to reducing the cytotoxicity and increasing the stability of the plasmid complexes, the PEG center block and the short P(HEMA) end blocks also help to enhance the gene transfection efficiency. Thus, the approach to well-defined block copolymers via ATRP provides a versatile means for tailoring the structure of non-viral gene vectors to meet the requirements of low cytotoxicity, good stability and high transfection capability for gene therapy applications.

  12. Sphere formation of adipose stem cell engineered by poly-2-hydroxyethyl methacrylate induces in vitro angiogenesis through fibroblast growth factor 2.

    PubMed

    Kim, Jong-Ho; Lim, I-Rang; Joo, Hyung Joon; Choi, Seung-Cheol; Choi, Ji-Hyun; Cui, Long-Hui; Im, Lisa; Hong, Soon Jun; Lim, Do-Sun

    A number of researchers have been reporting a wide range of in vitro and in vivo studies of cell engraftment to enhance angiogenesis using stem cells. Despite these efforts, studies involving three-dimensional (3D) culture method that mimics in vivo environment have not reached its peak yet. In this study, we investigated the change and effects on cellular angiogenic growth factors through sphere formation of adipose stem cell (ASC) which is engineered by poly-2-hydroxyethyl methacrylate (Poly-HEMA). First of all, we successfully induced sphere formation of ASC (sph-ASC) on Poly-HEMA coated plates. sph-ASC represented significantly higher expression levels of anti-apoptotic and hypoxic factors compared to monolayer adherent ASC (adh-ASC). Interestingly, sph-ASC showed higher mRNA levels of the following genes; CD31, CD144, vWF, IGF-2, MCP-1, PDGF-A, VEGF-A, VEGF-C, and FGF-2. In addition, mRNA expressions of angiogenic growth factor receptors such as Flk1, FGFR1, FGFR2, and Tie2 were elevated in sph-ASC. In protein level, Cytokine/Chemokines antibody array revealed a significant increase of FGF-2 in sph-ASC (3.17-fold) compared to adh-ASC. To investigate the effects of FGF-2 on sph-ASC, Matrigel angiogenic invasion assay showed significant reduced level of FGF-2 in FGF-2 siRNA transfected sph-ASC (2.27-fold) compared to negative control siRNA transfected sph-ASC. These findings suggest that Poly-HEMA coated plates induce sphere formation of ASC which has significantly higher expression of FGF-2, and plays a critical role as a major regulating growth factor of in vitro angiogenesis.

  13. Poly(2-hydroxyethyl methacrylate) for enzyme immobilization: impact on activity and stability of horseradish peroxidase.

    PubMed

    Lane, Sarah M; Kuang, Zhifeng; Yom, Jeannie; Arifuzzaman, Shafi; Genzer, Jan; Farmer, Barry; Naik, Rajesh; Vaia, Richard A

    2011-05-09

    On the basis of their versatile structure and chemistry as well as tunable mechanical properties, polymer brushes are well-suited as supports for enzyme immobilization. However, a robust surface design is hindered by an inadequate understanding of the impact on activity from the coupling motif and enzyme distribution within the brush. Herein, horseradish peroxidase C (HRP C, 44 kDa), chosen as a model enzyme, was immobilized covalently through its lysine residues on a N-hydroxysuccinimidyl carbonate-activated poly(2-hydroxyethyl methacrylate) (PHEMA) brush grafted chemically onto a flat impenetrable surface. Up to a monolayer coverage of HRP C is achieved, where most of the HRP C resides at or near the brush-air interface. Molecular modeling shows that lysines 232 and 241 are the most probable binding sites, leading to an orientation of the immobilized HRP C that does not block the active pocket of the enzyme. Michaelis-Menten kinetics of the immobilized HRP C indicated little change in the K(m) (Michaelis constant) but a large decrease in the V(max) (maximum substrate conversion rate) and a correspondingly large decrease in the k(cat) (overall catalytic rate). This indicates a loss in the percentage of active enzymes. Given the relatively ideal geometry of the HRPC-PHEMA brush, the loss of activity is most likely due to structural changes in the enzyme arising from either secondary constraints imposed by the connectivity of the N-hydroxysuccinimidyl carbonate linking moiety or nonspecific interactions between HRP C and DSC-PHEMA. Therefore, a general enzyme-brush coupling motif must optimize reactive group density to balance binding with neutrality of surroundings.

  14. Rose bengal in poly(2-hydroxyethyl methacrylate) thin films: self-quenching by photoactive energy traps

    NASA Astrophysics Data System (ADS)

    Ezquerra Riega, Sergio D.; Rodríguez, Hernán B.; San Román, Enrique

    2017-03-01

    The effect of dye concentration on the fluorescence,ΦF, and singlet molecular oxygen,ΦΔ, quantum yields of rose bengal loaded poly(2-hydroxyethyl methacrylate) thin films (∼200 nm thick) was investigated, with the aim of understanding the effect of molecular interactions on the photophysical properties of dyes in crowded constrained environments. Films were characterized by absorption and fluorescence spectroscopy, singlet molecular oxygen (1O2) production was quantified using a chemical monitor, and the triplet decay was determined by laser flash-photolysis. For the monomeric dilute dye, ΦF = 0.05 ± 0.01 and ΦΔ = 0.76 ± 0.14. The effect of humidity and the photostability of the dye were also investigated. Spectral changes in absorption and fluorescence in excess of 0.05 M and concentration self-quenching after 0.01 M are interpreted in the context of a quenching radius model. Calculations of energy migration and trapping rates were performed assuming random distribution of the dye. Best fits of fluorescence quantum yields with concentration are obtained in the whole concentration range with a quenching radius r Q = 1.5 nm, in the order of molecular dimensions. Agreement is obtained only if dimeric traps are considered photoactive, with an observed fluorescence quantum yield ratio ΦF,trap/ΦF,monomer ≈ 0.35. Fluorescent traps are capable of yielding triplet states and 1O2. Results show that the excited state generation efficiency, calculated as the product between the absorption factor and the fluorescence quantum yield, is maximized at around 0.15 M, a very high concentration for random dye distributions. Relevant information for the design of photoactive dyed coatings is provided.

  15. Rose bengal in poly(2-hydroxyethyl methacrylate) thin films: self-quenching by photoactive energy traps.

    PubMed

    Ezquerra Riega, Sergio D; Rodríguez, Hernán B; San Román, Enrique

    2017-03-09

    The effect of dye concentration on the fluorescence,ΦF, and singlet molecular oxygen,ΦΔ, quantum yields of rose bengal loaded poly(2-hydroxyethyl methacrylate) thin films (∼200 nm thick) was investigated, with the aim of understanding the effect of molecular interactions on the photophysical properties of dyes in crowded constrained environments. Films were characterized by absorption and fluorescence spectroscopy, singlet molecular oxygen ((1)O2) production was quantified using a chemical monitor, and the triplet decay was determined by laser flash-photolysis. For the monomeric dilute dye, ΦF = 0.05 ± 0.01 and ΦΔ = 0.76 ± 0.14. The effect of humidity and the photostability of the dye were also investigated. Spectral changes in absorption and fluorescence in excess of 0.05 M and concentration self-quenching after 0.01 M are interpreted in the context of a quenching radius model. Calculations of energy migration and trapping rates were performed assuming random distribution of the dye. Best fits of fluorescence quantum yields with concentration are obtained in the whole concentration range with a quenching radius r Q = 1.5 nm, in the order of molecular dimensions. Agreement is obtained only if dimeric traps are considered photoactive, with an observed fluorescence quantum yield ratio ΦF,trap/ΦF,monomer ≈ 0.35. Fluorescent traps are capable of yielding triplet states and (1)O2. Results show that the excited state generation efficiency, calculated as the product between the absorption factor and the fluorescence quantum yield, is maximized at around 0.15 M, a very high concentration for random dye distributions. Relevant information for the design of photoactive dyed coatings is provided.

  16. A poly(N-isopropylacrylamide-co-N-acryloxysuccinimide-co-2-hydroxyethyl methacrylate) composite hydrogel membrane for urease immobilization to enhance urea hydrolysis rate by temperature swing*

    PubMed

    Chen; Chiu

    2000-03-01

    A composite membrane made of cross-linked poly(N-isopropylacrylamide-co-N-acryloxysuccinimide-co-2-hydroxyethyl methacrylate) (p(NIPAAm-NAS-HEMA)) hydrogel on polyester nonwoven support has been synthesized. The composite membrane shows temperature-responsive properties similar to conventional PNIPAAm hydrogels beads, which reversibly swells below and de-swells above the lower critical solution temperature of PNIPAAm (around 32 to 33 degrees C). Diffusion of urea through the membrane was temperature-dependent with the effective diffusion coefficient at 20 degrees C being 18 times that at 60 degrees C. Urease was immobilized directly to the membrane by forming covalent bonds between its amino groups and the succinimide ester groups of the membrane. Membrane prepared with NIPAAm to NAS molar ratio of 9, and then reacted in pH 7 buffer with 6 mg of urease gave the best immobilized enzyme, where 0.102 mg protein and 5.71 U activity per cm(2) membrane, and 55% relative specific activity could be obtained. There was negligible internal mass transfer resistance for this preparation judging from the calculated effectiveness factor. Urease shows enhanced thermal stability after immobilization with the first-order inactivation rate constant at 70 degrees C decreased to 1/8 of that of free urease. Membrane-immobilized urease could be utilized in a two-compartment membrane reactor with temperature swing to substantially enhance urea hydrolysis rate. The best operating condition of the membrane reactor was with temperature cycling between 60 to 20 degrees C and with temperature change every 10 min, where concentration of product ammonia after 3 h reaction increased 3.8-folds when compared with isothermal operation at 60 degrees C.

  17. Synthesis of poly (2-hydroxyethyl methacrylate) (PHEMA) based nanoparticles for biomedical and pharmaceutical applications.

    PubMed

    Saini, Rajesh; Bajpai, Jaya; Bajpai, Anil K

    2012-01-01

    The performance of polymeric nanomaterials relies greatly upon their properties which are intimately related to the methods of fabrication of the materials. Among various synthetic polymers, the polymers of 2-hydroxyetyhyl methacrylate (PHEMA) maintain a prime position in biomedical field due to their useful physicochemical properties and suitability for controlled drug delivery applications. Here we focus on three methods of preparation of PHEMA nanoparticles, by suspension polymerization, emulsion polymerization and dispersion polymerization without the use of any surfactants.

  18. Nano-network with dual temperature and pH responsiveness based on copolymers of 2-hydroxyethyl methacrylate with 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane

    NASA Astrophysics Data System (ADS)

    Chiriac, Aurica P.; Nita, Loredana E.; Nistor, Manuela T.

    2011-12-01

    This study refers to the synthesis of a nano-network with dual temperature and pH responsiveness based on the 2-hydroxyethyl methacrylate (HEMA) copolymers with a comonomer with spiroacetal moiety and crosslinking capacity, namely 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane (U). The copolymers were synthesized by radical emulsion polymerization, using 4,4'-azobis(cyanopentanoic acid) as initiator, in the presence of sodium lauryl sulfate as tensioactive agent and poly(vinyl alcohol) as protective colloid. Three copolymer variants were taken into study resulted from the different ratio between the comonomers (HEMA/U), which was about 98/2, 95/5, and 90/10, respectively. The copolymers were characterized by FTIR and thermal analysis. The copolymers sensitivity was evidenced by studying the evolution of the hydrodynamic radius and zeta potential of the polymeric particles as a function of pH. Thus, the particles size increases with the comonomer amount, from 193 nm in case of the homopolymer up to 253 nm for the copolymer with maximum content of the comonomer (10%). The increase of the particle hydrodynamic radius with the growth of temperature was also put into evidence.

  19. Chitosan-functionalised poly(2-hydroxyethyl methacrylate) core-shell microgels as drug delivery carriers: salicylic acid loading and release.

    PubMed

    Mahattanadul, Natshisa; Sunintaboon, Panya; Sirithip, Piyawan; Tuchinda, Patoomratana

    2016-09-01

    This work presents the evaluation of chitosan-functionalised poly(2-hydroxyethyl methacrylate) (CS/PHEMA) core-shell microgels as drug delivery carriers. CS/PHEMA microgels were prepared by emulsifier-free emulsion polymerisation with N,N '-methylenebisacrylamide (MBA) as a crosslinker. The study on drug loading, using salicylic acid (SA) as a model drug, was performed. The results showed that the encapsulation efficiency (EE) increased as drug-to-microgel ratio was increased. Higher EE can be achieved with the increase in degree of crosslinking, by increasing the amount of MBA from 0.01 g to 0.03 g. In addition, the highest EE (61.1%) was observed at pH 3. The highest release of SA (60%) was noticed at pH 2.4, while the lowest one (49.4%) was obtained at pH 7.4. Moreover, the highest release of SA was enhanced by the presence of 0.2 M NaCl. The pH- and ionic-sensitivity of CS/PHEMA could be useful as a sustained release delivery device, especially for oral delivery.

  20. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate.

    PubMed

    Barbu, Eugen; Verestiuc, Liliana; Iancu, Mihaela; Jatariu, Anca; Lungu, Adriana; Tsibouklis, John

    2009-06-03

    Nanoparticulate hybrid polymeric hydrogels (10-70 nm) have been obtained via the radical-induced co-polymerization of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate, and the materials have been investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. Studies on the effects of network structure upon swelling properties, adhesiveness to substrates that mimic mucosal surfaces and biodegradability, coupled with in vitro drug release investigations employing ophthalmic drugs with differing aqueous solubilities, have identified nanoparticle compositions for each of the candidate drug molecules. The hybrid nanoparticles combine the temperature sensitivity of N-isopropylacrylamide or the good swelling characteristics of 2-hydroxyethyl methacrylate with the susceptibility of chitosan to lysozyme-induced biodegradation.

  1. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Barbu, Eugen; Verestiuc, Liliana; Iancu, Mihaela; Jatariu, Anca; Lungu, Adriana; Tsibouklis, John

    2009-06-01

    Nanoparticulate hybrid polymeric hydrogels (10-70 nm) have been obtained via the radical-induced co-polymerization of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate, and the materials have been investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. Studies on the effects of network structure upon swelling properties, adhesiveness to substrates that mimic mucosal surfaces and biodegradability, coupled with in vitro drug release investigations employing ophthalmic drugs with differing aqueous solubilities, have identified nanoparticle compositions for each of the candidate drug molecules. The hybrid nanoparticles combine the temperature sensitivity of N-isopropylacrylamide or the good swelling characteristics of 2-hydroxyethyl methacrylate with the susceptibility of chitosan to lysozyme-induced biodegradation.

  2. Release of gentamicin sulphate from a modified commercial bone cement. Effect of (2-hydroxyethyl methacrylate) comonomer and poly(N-vinyl-2-pyrrolidone) additive on release mechanism and kinetics.

    PubMed

    Frutos, P; Diez-Peña, E; Frutos, G; Barrales-Rienda, J M

    2002-09-01

    The influence of the (2-hydroxyethyl methacrylate) (HEMA) monomer addition as a comonomer to the cement liquid component and of a polymer, poly(N-vinyl-2-pyrrolidone) (PVP) to the solid component of a standard CMW-1 bone cement on gentamicin sulphate (GS) on its drug release properties have been studied. The addition of HEMA modifies the habit of the delivery curves. The incorporation of PVP into the cement matrix, apparently, did not very much modify the shape of the HEMA modified cement release curves, but led to a remarkable increase of the maximum amount of GS released. This effect was proportional to the PVP concentration incorporated. From the matrix composition and SEM data, a model based on the morphology of the matrix has been proposed. The cumulative amount of GS released by each slab Mt is most adequately fitted and represented by the equation Mt = c + at 1/2 + b[1 - exp(-nt)], which corroborates that the release occurs according to the model proposed. by means of three discrete mechanisms, namely: (i) a short-term initial elution due to the imperfections in the poly(methyl methacrylate) covering of the most external GS beads, burst effect by the buffer solution; (ii) followed by a fracture by stress cracking in an active media of the coated GS beads located on the external surface of the matrix where water molecules enter to dissolve GS molecules releasing them into the buffer solution by a diffusion-controlled process; and (iii) a third process in which the buffer solution penetrates into the internal voids and cracks creating a series of channels in a labyrinthic structure, which may facilitate the access of water molecules to the plastic-coated GS beads within the bulk matrix. This third process is enhanced by the incorporation of PVP beads as dissolved molecules within the matrix. This water-soluble additive is leachable, generating a highly porous structure in the cement. This HEMA and PVP modified cement may be used as a drug delivery system to

  3. Excited-state proton-transfer dynamics of 1-methyl-6-hydroxyquinolinium embedded in a solid matrix of poly(2-hydroxyethyl methacrylate).

    PubMed

    Park, Sun-Young; Lee, Young-Shin; Jang, Du-Jeon

    2008-11-28

    The excited-state intrinsic proton transfer and its geminate recombination, as well as the ground-state equilibria, of 1-methyl-6-hydroxyquinolinium embedded in a solid matrix of poly(2-hydroxyethyl methacrylate) have been studied by measuring time-resolved and steady-state fluorescence spectra along with absorption and excitation spectra. Proton transfer takes place within 3.3 ns to form ion pairs while its back-reaction occurs on the time scale of 3.7 ns. The ion pairs in the rigid alcoholic matrix go through neither diffusion to form free ions nor subsequent electronic rearrangement to form the keto species within their excited-state lifetimes.

  4. Synthesis and evaluation of chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) as a drug carrier for controlled release of tramadol hydrochloride.

    PubMed

    Subramanian, Kaliappa Gounder; Vijayakumar, Vediappan

    2012-07-01

    Chitosan-graft-poly (2-hydroxyethyl methacrylate-co-itaconic acid) has been synthesized for different feed ratios of 2-hydroxyethyl methacrylate and itaconic acid and characterized by FT-IR, thermogravimetry and swelling in simulated biological fluids (SBF) and evaluated as a drug carrier with model drug, tramadol hydrochloride (TRM). Grafting decreased the thermal stability of chitosan. FT-IR spectra of tablet did not reveal any molecular level (i.e. at <10 nm scale) drug-polymer interaction. But differential scanning calorimetric studies indicated a probable drug-polymer interaction at a scale >100 nm level. The observed Korsmeyer-Peppas's power law exponents (0.19-1.21) for the in vitro release profiles of TRM in SBF and other drugs such as 5-fluorouracil (FU), paracetamol (PCM) and vanlafaxine hydrochloride (VNF) with the copolymer carriers revealed an anomalous drug release mechanism. The decreased release rates for the grafted chitosan and the enhanced release rate for the grafts with increasing itaconic acid content in the feed were more likely attributed to the enhanced drug-matrix interaction and polymer-SBF interactions, respectively. The different release profiles of FU, PCM, TRM and VNF with the copolymer matrix are attributed to the different chemical structures of drugs. The above features suggest the graft copolymer's candidature for use as a promising oral drug delivery system.

  5. Effect of calcium sulphate nanorods on mechanical properties of chitosan-hydroxyethyl methacrylate (HEMA) copolymer nanocomposites.

    PubMed

    Bari, Sarang S; Mishra, Satyendra

    2017-02-10

    Copolymers of chitosan and hydroxyetheyl methacrylate (HEMA) were successfully synthesized using ceric ammonium nitrate (CAN) as an initiator, via in situ polymerization method, followed by efficacious preparation of their nanocomposites by incorporating calcium sulphate nanorods via solution blending process. Hydrophilicity studies confirmed that grafting of HEMA in the backbone of the hydrophobic chitosan chains induced the improvement in hydrophilicity of chitosan, while mechanical properties of the nanocomposites were also enhanced significantly up to 20%, due to availability of enlarged surface area and higher aspect ratio of CaSO4 nanorods. This was supported by FE-SEM and XRD analysis in terms of proper distribution of nanofiller through the copolymer matrix and corresponding rise in percentage crystallanity respectively. Results obtained from biodegradation studies proved the efficiency of CaSO4 nanofillers to improve biomechanical strength of chitosan nanocomposites, without affecting their normal degradation profile that renders the products to be applicable for biomedical applications.

  6. [In vitro study of the effect of bisphosphonates on mineralization induced by a composite material: poly 2(hydroxyethyl) methacrylate coupled with alkaline phosphatase].

    PubMed

    Filmon, R; Baslé, M F; Barbier, A; Chappard, D

    2000-03-01

    We have immobilized the mineralizing agent alkaline phosphatase (AlkP) in a hydrophilic polymer (poly 2(hydroxyéthyl) methacrylate) (pHEMA) in a copolymerization technique. Histochemical study on polymer sections revealed that AlkP has retained its biological activity. The image analysis of sections using a tessellation method showed a lognormal distribution of the area of the tiles surrounding AlkP particles thus confirming a homogeneous distribution of the enzyme in the polymer. Pellets of pHEMA-AlkP were incubated with a synthetic body fluid containing organic phosphates (beta-glycerophosphate). Mineral deposits with a rounded shape (calcospherites) were obtained in about 17 days. We have investigated the effects of three bisphosphonates (etidronate, alendronate and tiludronate) on this system. Bisphosphonates at a concentration of 10(-2) M totally inhibited AlkP in solution at a concentration of 10(-4) mg/ml. Inhibition has been reported being due to the chelation of a metal cofactor (Zn2+). Etidronate and alendronate appeared to inhibit the calcospherite deposition onto the pHEMA-AlkP material in a similar way. Both bisphosphonates possess three sites for mineral complexion. On the other hand, tiludronate having only two sites was associated with a reduced inhibitory effect on mineralization. When used in microgravity conditions, mineralization was impaired with etidronate and larger crystals were obtained with tiludronate. However, these effects were obtained in non-physiological conditions (a 20 degrees C temperature was used during the STS80 flight of the space shuttle). The pHEMA-AlkP material provides an interesting method to study the effects of pharmacological compounds and environmental factors on the bone and cartilage mineralization process.

  7. A methyl methacrylate-HEMA-CL(n) copolymerization investigation: from kinetics to bioapplications.

    PubMed

    Ferrari, Raffaele; Rooney, Thomas R; Lupi, Monica; Ubezio, Paolo; Hutchinson, Robin A; Moscatelli, Davide

    2013-10-01

    The radical copolymerization kinetics of methyl methacrylate (MMA) and poly-ϵ-caprolactone macromonomer functionalized with a vinyl end group (HEMA-CL(n)) is studied using a pulsed-laser technique. The reactivity ratios for this system are near unity, while a linear relationship between k(p,cop), the copolymer-averaged propagation rate coefficient, and the composition of macromonomer in the feed (0-80 wt% range) is determined. At 50 wt% macromonomer in the feed, a 1.67 ± 0.02 and 1.64 ± 0.06 increase in k(p,cop)/k(p,MMA) is determined for HEMA-CL3 and HEMA-CL2, respectively. These macromonomers are adopted to synthesize nanoparticles (NPs) in the range of 100-150 nm through batch emulsion free radical polymerization (BEP) to produce partially degradable drug delivery carriers. The produced NPs are tested in 4T1 cell line and show excellent characteristics as carriers: they do not affect cell proliferation, and a relevant number of NPs, thousands per cell, are internalized.

  8. Gelatin-loaded p(HEMA-GMA) cryogel for high-capacity immobilization of horseradish peroxidase.

    PubMed

    Soomro, Rabel; Perçin, Işık; Memon, Najma; Iqbal Bhanger, Muhammad; Denizli, Adil

    2016-11-01

    Poly(2-hydroxyethyl methacrylate-glycidyl methacrylate) [p(HEMA-GMA)] cryogel discs were prepared under sub-zero temperatures. Gelatin was attached covalently on the p(HEMA-GMA) cryogel discs and reversible immobilization of horseradish peroxidase (HRP) was performed. The p(HEMA-GMA) cryogel discs were characterized by swelling tests, scanning electron microscopy, and surface area measurements. HRP immobilization capacity of p(HEMA-GMA)/gelatin cryogel discs was 24.8 mg/g. Removal of phenol from aqueous solutions was performed using HRP immobilized p(HEMA-GMA)/gelatin cryogel. It was observed that within 2 h of contact time, the percentage of phenol removal reaches up to 91% in the presence of H2O2.

  9. FT-IR and FT-Raman spectra of 2-hydroxyethyl methacrylate--A conformational and vibrational analysis.

    PubMed

    Belaidi, O; Adjim, M; Bouchaour, T; Maschke, U

    2015-09-05

    A conformational search of the flexible 2-hedroxyethyl methacrylate molecule by semi-empirical AM1 and B3LYP formalisms leads to six stable conformations. Four of them are in the s-trans conformation. The optimized geometries at DFT using 6-311+G(∗∗) basis set are in good agreement with experimental electron diffraction data of the methyl methacrylate molecule, thereby the s-trans is the most stable form. The harmonic frequencies at the fully optimized geometries of all conformers have been performed at the DFT//B3LYP/6-311+G(∗∗) level of theory. Infrared and Raman intensities and potential energy distributions of the scaled harmonic frequencies are used for the assignment of the observed IR and Raman bands. We noticed a good agreement between the experimental and the computed spectra. The strong band at 1081 cm(-1), in the infrared spectrum, maybe used as a characteristic band of the s-trans conformation. Henceforth, the less stable structure contribute alone for reproducing the Raman bands located at 276 (sh) and 3020 (vw) cm(-1).

  10. Poly(Lactic Acid) Hemodialysis Membranes with Poly(Lactic Acid)-block-Poly(2-Hydroxyethyl Methacrylate) Copolymer As Additive: Preparation, Characterization, and Performance.

    PubMed

    Zhu, Lijing; Liu, Fu; Yu, Xuemin; Xue, Lixin

    2015-08-19

    Poly(lactic acid) (PLA) hemodialysis membranes with enhanced antifouling capability and hemocompatibility were developed using poly(lactic acid)-block-poly(2-hydroxyethyl methacrylate) (PLA-PHEMA) copolymers as the blending additive. PLA-PHEMA block copolymers were synthesized via reversible addition-fragmentation (RAFT) polymerization from aminolyzed PLA. Gel permeation chromatography (GPC) and (1)H-nuclear magnetic resonance ((1)H NMR) were applied to characterize the synthesized products. By blending PLA with the amphiphilic block copolymer, PLA/PLA-PHEMA membranes were prepared by nonsolvent induced phase separation (NIPS) method. Their chemistry and structure were characterized with X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and atomic force microscopy (AFM). The results revealed that PLA/PLA-PHEMA membranes with high PLA-PHEMA contents exhibited enhanced hydrophilicity, water permeability, antifouling and hemocompatibility. Especially, when the PLA-PHEMA concentration was 15 wt %, the water flux of the modified membrane was about 236 L m(-2) h(-1). Its urea and creatinine clearance was more than 0.70 mL/min, lysozyme clearance was about 0.50 mL/min, BSA clearance was as less as 0.31 mL/min. All the results suggest that PLA-PHEMA copolymers had served as effective agents for optimizing the property of PLA-based membrane for hemodialysis applications.

  11. Curcumin loaded poly(2-hydroxyethyl methacrylate) nanoparticles from gelled ionic liquid--in vitro cytotoxicity and anti-cancer activity in SKOV-3 cells.

    PubMed

    Kumar, Sathish Sundar Dhilip; Surianarayanan, Mahadevan; Vijayaraghavan, R; Mandal, Asit Baran; MacFarlane, D R

    2014-01-23

    The main focus of this study is to encapsulate hydrophobic drug curcumin in hydrophilic polymeric core such as poly(2-hydroxyethyl methacrylate) [PHEMA] nanoparticles from gelled ionic liquid (IL) to improve its efficacy. We have achieved 26.4% drug loading in a biocompatible hydrophilic polymer. Curcumin loaded PHEMA nanoparticles (C-PHEMA-NPs) were prepared by nano-precipitation method. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis showed that the prepared nanoparticles were spherical in shape and free from aggregation. The size and zeta potential of prepared C-PHEMA-NPs were about 300 nm and -33.4 mV respectively. C-PHEMA-NPs were further characterized by FT-IR spectroscopy which confirmed the existence of curcumin in the nanoparticles. X-ray diffraction and differential scanning calorimetry studies revealed that curcumin present in the PHEMA nanoparticles were found to be amorphous in nature. The anticancer activity of C-PHEMA-NPs was measured in ovarian cancer cells (SKOV-3) in vitro, and the results revealed that the C-PHEMA-NPs had better tumor cells regression activity than free curcumin. Flow cytometry showed the significant reduction in G0/G1 cells after treatment with C-PHEMA-NPs and molecular level of apoptosis were also studied using western blotting. Toxicity of PHEMA nanoparticles were studied in zebrafish embryo model and results revealed the material to be highly biocompatible. The present study demonstrates the curcumin loaded PHEMA nanoparticles have potential therapeutic values in the treatment of cancer.

  12. Ablation of poly(methyl methacrylate) and poly(2-hydroxyethyl methacrylate) by 308, 222 and 193 nm excimer-laser radiation

    NASA Astrophysics Data System (ADS)

    Costela, A.; Figuera, J. M.; Florido, F.; García-Moreno, I.; Collar, E. P.; Sastre, R.

    1995-03-01

    Data on the ablation of Poly(Methyl MetAcylate) (PMMA) and Poly(2-Hydroxyethyl MetAcylate) (PHEMA) with 0%, 1% and 20% of Ethylene Glycol DiMethAcrylate (EGDMA) as crosslinking monomer by 193, 222 and 308 nm laser radiation are presented. Direct photoetching of PMMA at 308 nm is demonstrated for laser fluences ranging from 2 to 18 J/cm2. The ablation rate of PHEMA is lower than the corresponding to PMMA and decreases when the amount of EGDMA increases. The determination of the absorbed energy density required to initiate significant ablation suggests that the photoetching mechanism is similar for all the polymers studied and is a function of the irradiation wavelength. The Beer-Lambert law, the Srinivasan, Smrtic and Babu (SSB) theory and the kinetic model of the moving interface are used to analyze the experimental results. It is shown that only the moving interface theory fits well the etch rate for all the selected polymers at the three radiation wavelengths.

  13. Preparation and evaluation of a hydrophilic poly(2-hydroxyethyl methacrylate-co-N,N'-methylene bisacrylamide) monolithic column for pressurized capillary electrochromatography.

    PubMed

    Cheng, Jintian; Chen, Xiadi; Cai, Yimin; He, Yu; Chen, Zongbao; Lin, Zian; Zhang, Lan

    2013-04-01

    A polar polymethacrylate-based monolithic column was introduced and evaluated as a hydrophilic interaction CEC stationary phase. The monolithic stationary phase was prepared by in situ copolymerization of a neutral monomer 2-hydroxyethyl methacrylate and a polar cross-linker N,N'-methylene bisacrylamide in a binary porogenic solvent consisting of dodecyl alcohol and toluene. The hydroxyl and amino groups at the surface of the monolithic stationary phase provided polar sites which were responsible for hydrophilic interactions. The composition and proportion of the polymerization mixture was investigated in detail. The mechanical stability and reproducibility of the obtained monolithic column preformed was satisfied. The effects of pH and organic solvent content on the EOF and the separation of amines, nucleosides, and narcotics on the optimized monolithic column were investigated. A typical hydrophilic interaction CEC was observed on the neutral polar stationary phase. The optimized monolithic column can obtain high-column efficiencies with 62,000-126,000 theoretical plates/m and the RSDs of column-to-column (n = 9), run-to-run (n = 5), and day-to-day (n = 3) reproducibility were less than 6.3%. The calibration curves of these five narcotics exhibited good linearity with R in the range of 0.9959-0.9970 and linear ranges of 1.0-200.0 μg/mL. The detection limits at S/N = 3 were between 0.2 and 1.2 μg/mL. The recoveries of the separation of narcotics on the column were in the range of 84.0-108.6%. The good mechanical stability, reproducibility, and quantitation capacity was suitable for pressure-assisted CEC applications.

  14. Spectroscopic analysis of Pr^3+ (4f^2) absorption intensities in a plastic host (HEMA).

    NASA Astrophysics Data System (ADS)

    Stonestreet, David; Nash, Kelly; Dee, Doug; Yow, Raylon; Gruber, John; Sardar, Dhiraj

    2006-10-01

    A spectroscopic investigation has been performed on the Pr^3+ ions embedded in 2-hydroxyethyl methacrylate (HEMA) solid plastic host. The standard Judd-Ofelt analysis was applied to the room temperature absorption intensities of Pr^3+ transitions to determine three phenomenological intensity parameters: φ2, φ4 and φ6. Values of the intensity parameters were subsequently used to determine the decay rates (emission probabilities), radiative lifetimes, and branching ratios of the principal intermanifold transitions of Pr^3+ from the ^3P2, ^1D2, and ^3P0 manifold states to the lower-lying manifolds. The spectroscopic properties Pr^3+ in HEMA will be compared with those in glasses.

  15. Indomethacin-loaded polymer nanocarriers based on poly(2-hydroxyethyl methacrylate-co-3,9-divinyl-2,4,8,10-tetraoxaspiro (5.5) undecane): preparation, in vitro and in vivo evaluation.

    PubMed

    Nita, Loredana E; Chiriac, Aurica P; Nistor, Manuela T; Tartau, Liliana

    2012-05-01

    The study is focused on the development of copolymers based on poly(2-hydroxyethyl methacrylate-co-3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5]-undecane). The macromolecular compounds were synthesized by dispersion polymerization in the presence of the radical initiator 4,4'-azobis(cyanopentanoic acid) and using sodium lauryl sulfate as tensioactive compound and poly(aspartic acid) (PAS) as protective colloid. PAS presents biocompatibility and biodegradability, and assures the increase of the absorbent character for the new synthesized network, and also, can supplement the hydrogen bonds contributing to the stability of the achieved complexes. The prepared polymeric networks were characterized by FTIR, SEM, and thermogravimetric analyses. The dependence on the pH of the swelling degree equilibrium was also evaluated correlated also with different temperature values. The poly(2-hydroxyethyl methacrylate-co-3,9-divinyl-2,4,8,10-tetraoxaspiro [5.5]-undecane) copolymers were evaluated as matrix for indomethacin (INN) as model drug loaded onto these polymeric networks. The evaluation of the homogeneity distribution of the INN drug in polymeric network was made by near infrared chemical imaging (NIR-CI) and correspondingly statistical analysis. The pharmacokinetic profile was achieved performing the in vitro release of the INN drug from the polymeric network. The data resulted from the in vivo experimental studies, respectively the biocompatibility tests, somatic nociceptive experimental model (Tail flick test) and visceral nociceptive experimental model (Writhing test)-are also reported in the study.

  16. In situ synthesis of cobalt ferrite nanoparticle/polymer hybrid from a mixed Fe-Co methacrylate for magnetic hyperthermia

    NASA Astrophysics Data System (ADS)

    Hayashi, Koichiro; Maeda, Kazuki; Moriya, Makoto; Sakamoto, Wataru; Yogo, Toshinobu

    2012-09-01

    Hyperthermic CoFe2O4 nanoparticle (CFO NP)/polymer hybrids were synthesized by hydrolysis-condensation from a complex of Co and Fe possessing methacrylate ligands. Single-crystal analysis revealed that the complex consisted of two Co and four Fe metal atoms coordinated by methacrylate and 2-methoxyethoxy groups. The complex was copolymerized with 2-hydroxyethyl methacrylate (HEMA) and the resulting copolymer was then hydrolyzed to form a CFO NP/copolymer of poly(methacrylate) and poly(2-hydroxyethyl methacrylate) hybrid. Copolymerization with HEMA enhanced the stability of the hybrid in water. The size and magnetic properties of CFO in the hybrid were controlled by adjusting the hydrolysis conditions. Moreover, the hybrid generated heat under an alternating current magnetic field; its exothermal properties depended on the magnetic properties of the hybrid, the strength of the applied field, and the CFO NP content in the agar phantom matrix.

  17. Sorption of DNA by diatomite-Zn(II) embedded supermacroporous monolithic p(HEMA) cryogels

    PubMed Central

    Tozak, Kabil Özcan; Erzengin, Mahmut; Sargin, Idris; Ünlü, Nuri

    2013-01-01

    In this study, the DNA sorption performance of diatomite-Zn(II) embedded supermacroporous monolithic p(HEMA) cryogels were investigated for the purpose of designing a novel adsorbent that can be utilized for DNA purification, separation and immunoadsorption studies such as removal of anti-dsDNA antibodies from systemic lupus erythematosus (SLE) patient plasma. Poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based monolithic cryogel column embedded with Zn2+-diatomite particles was prepared by free radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N'-methylene-bis-acrylamide (MBAAm). The polymerization reaction was initiated by N,N,N',N'-tetramethylene diamine (TEMED) and ammonium persulfate (APS) pair in an ice bath. After thawing, the monolithic composite cryogels were used for affinity sorption and then subsequent desorption of DNA molecules from aqueous solutions. Diatomite (DA) particles were characterized by XRF and BET method. The characterization of composite cryogel was done through SEM imaging. The effects of pH of the solution, initial DNA concentration, ionic strength, temperature and flow rates on adsorption were investigated to determine the optimum conditions for adsorption/desorption experiments. The particle embedding procedure was shown to yield significantly enhanced adsorption of DNA on the adsorbent. Furthermore, considering its excellent bio-compatibility, p(HEMA) cryogels are promising a candidate for further DNA sorption studies. PMID:26600734

  18. Synthesis and characterization of a novel semi-IPN hydrogel based on Salecan and poly(N,N-dimethylacrylamide-co-2-hydroxyethyl methacrylate).

    PubMed

    Hu, Xinyu; Feng, Liandong; Wei, Wei; Xie, Aming; Wang, Shiming; Zhang, Jianfa; Dong, Wei

    2014-05-25

    Salecan is a novel water-soluble, high molecular mass extracellular β-glucan produced by Agrobacterium sp. ZX09. Salecan has excellent physicochemical and biological properties, making it very suitable for hydrogel preparation. In this study, a series of novel semi-interpenetrating polymer network (semi-IPN) hydrogels containing Salecan and poly(N,N-dimethylacrylamide-co-2-hydroxyethylmethacrylate) (poly(DMAA-co-HEMA)) were synthesized by radical polymerization and semi-IPN technology. Structure and morphology of the hydrogels were characterized by FTIR, XRD, TGA and SEM. The semi-IPNs had a well-interconnected porous structure with tunable pore size ranging from 6 to 41μm. Swelling capability of the hydrogels was improved by introducing the hydrophilic Salecan. Rheological results indicated that the incorporation of poly(DMAA-co-HEMA) into hydrogels enhanced the storage modulus. Compression tests revealed that these semi-IPNs were robust materials with compressive modulus between 13.3 and 90.5kPa, the addition of Salecan increased the fracture strain from 71.1% to 88.8%. Degradation and cytotoxicity tests demonstrated that semi-IPNs were degradable and non-toxic.

  19. Drug loading optimization and extended drug delivery of corticoids from pHEMA based soft contact lenses hydrogels via chemical and microstructural modifications.

    PubMed

    García-Millán, Eva; Koprivnik, Sandra; Otero-Espinar, Francisco Javier

    2015-06-20

    This paper proposes an approach to improve drug loading capacity and release properties of poly(2-hydroxyethyl methacrylate) (p(HEMA)) soft contact lenses based on the optimization of the hydrogel composition and microstructural modifications using water during the polymerization process. P(HEMA) based soft contact lenses were prepared by thermal or photopolymerization of 2-hydroxyethyl methacrylate (HEMA) solutions containing ethylene glycol di-methacrylate as crosslinker and different proportions of N-vinyl-2-pyrrolidone (NVP) or methacrylic acid (MA) as co-monomers. Transmittance, water uptake, swelling, microstructure, drug absorption isotherms and in vitro release were characterized using triamcinolone acetonide (TA) as model drug. Best drug loading ratios were obtained with lenses containing the highest amount (200 mM) of MA. Incorporation of 40% V/V of water during the polymerization increases the hydrogel porosity giving a better drug loading capacity. In vitro TA release kinetics shows that MA hydrogels released the drug significantly faster than NVP-hydrogels. Drug release was found to be diffusion controlled and kinetics was shown to be reproducible after consecutive drug loading/release processes. Results of p(HEMA) based soft contact lenses copolymerized with ethylene glycol dimethacrylate (EGDMA) and different co-monomers could be a good alternative to optimize the loading and ocular drug delivery of this corticosteroid drug.

  20. Grafting chitosan and polyHEMA on carbon nanotubes surfaces: "grafting to" and "grafting from" methods.

    PubMed

    Mahmoodian, Hossein; Moradi, Omid; Shariatzadeh, Behnam

    2014-02-01

    We report a simple method for engineering chitosan (CS) functionalized multi-walled carbon nanotube (MWCNT) composites with a biomedically important polymer, poly-2-hydroxyethyl methacrylate (polyHEMA), by chemical grafting HEMA monomers via free radical polymerization. Functionalization of CS and polyHEMA occurred in three steps. First, using microwave irradiation, CS was grafted onto the surface and sidewall of the carbon nanotubes. Second, HEMA monomers were grafted onto the polymeric matrix surface. The final step involved free radical polymerization of HEMA monomers. Composite synthesis was confirmed by Fourier transform infrared (FTIR) spectroscopy. Moreover, the presence of polyHEMA on the surface of the CS functionalized carbon nanotubes was confirmed by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and thermo gravimetric analysis (TGA) analyses. Furthermore, in the aqueous phase, our novel composites exhibited higher dispersibility compared with pristine MWCNTs. Considering the biomedical importance of polyHEMA and CS polymers, we expect these materials to be useful in the pharmaceutical industry as novel biomaterial composites with potential applications in drug delivery.

  1. The study of adsorption characteristics Cu2+ and Pb2+ ions onto PHEMA and P(MMA-HEMA) surfaces from aqueous single solution.

    PubMed

    Moradi, O; Aghaie, M; Zare, K; Monajjemi, M; Aghaie, H

    2009-10-30

    The adsorption characteristics of Cu2+ and Pb2+ ions onto poly2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) adsorbent surfaces from aqueous single solution were investigated with respect to the changes in the pH of solution, adsorbent composition (changes in the weight percentage of MMA copolymerized with HEMA monomer), contact time and the temperature in the individual aqueous solutions. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained. The results revealed that the Langmuir isotherm fitted the experimental results better than the Freundlich isotherm. Using the Langmuir model equation, the monolayer adsorption capacity of PHEMA surface was found to be 0.840 and 3.037 mg/g for Cu2+ and Pb2+ ions and adsorption capacity of (PMMA-HEMA) was found to be 31.153 and 31.447 mg/g for Cu2+ and Pb2+ ions, respectively. Changes in the standard Gibbs free energy (DeltaG(0)), standard enthalpy (DeltaH(0)) and standard entropy (DeltaS(0)) show that the adsorption of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293-323 K.

  2. Laser surface modification of polymers to improve biocompatibility: HEMA grafted PDMS, in vitro assay—III

    NASA Astrophysics Data System (ADS)

    Khorasani, M. T.; Mirzadeh, H.; Sammes, P. G.

    1999-08-01

    Polydimethylsiloxane (PDMS) surface modifications were carried out using CO 2-pulsed laser, without photosensitizer at ambient condition, to introduce peroxide groups onto the PDMS surface. Such peroxides were capable of initiating graft polymerization of 2-hydroxyethyl methacrylate (HEMA) onto the PDMS. The modified surfaces were characterized using a variety of techniques including scanning electron microscopy (SEM), attenuated total reflectance infrared (ATR-FTIR) and the water drop contact angle measurements. Data from in vitro assays indicated a significant reduction of the platelet adhesion and aggregation for the modified surfaces.

  3. Preparation of pHEMA-CP composites with high interfacial adhesionvia template-driven mineralization

    SciTech Connect

    Song, Jie; Saiz, Eduardo; Bertozzi, Carolyn R.

    2002-12-05

    We report a template-driven nucleation and mineral growth process for the high-affinity integration of calcium phosphate (CP) with a poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel scaffold. A mineralization technique was developed that exposes carboxylate groups on the surface of crosslinked pHEMA, promoting high-affinity nucleation and growth of calcium phosphate on the surface along with extensive calcification of the hydrogel interior. External factors such as the heating rate, the agitation of the mineral stock solution and the duration of the process that affect the outcome of the mineralization were investigated. This template-driven mineralization technique provides an efficient approach toward bonelike composites with high mineral-hydrogel interfacial adhesion strength.

  4. Extruded, partially disintegrated, poly-HEMA orbital implant (AlphaSphere).

    PubMed

    Yadav, Prashant; Jakobiec, Frederick A; De Castro, Dawn K; Mendoza, Pia R; Fay, Aaron

    2014-01-01

    A 54-year-old diabetic man underwent enucleation for endophthalmitis. Secondary implantation of a 2-hydroxyethyl methacrylate (HEMA) sphere (AlphaSphere, Addition Technology) was performed 2 weeks later. Six weeks after insertion, noninfectious disintegration of sutured tissue planes represented by Tenon's capsule, rectus muscle, and conjunctiva occurred, requiring removal of the fragmenting implant before uncontrolled extrusion occurred. Histopathologic analysis revealed an absence of infectious pathogens and no tissue necrosis, but rather breakup of the implant material that elicited a granulomatous response with sparse T-lymphocytes and almost no polymorphonuclear leukocytes. This distinctively designed poly-HEMA orbital implant incited a dramatic and irreversible host tissue response. Investigation of other cases will be necessary to determine the frequency of such a complication and should include rigorous histopathologic techniques.

  5. Grafting of HEMA onto dopamine coated stainless steel by 60Co-γ irradiation method

    NASA Astrophysics Data System (ADS)

    Jin, Wanqin; Yang, Liming; Yang, Wei; Chen, Bin; Chen, Jie

    2014-12-01

    A novel method for grafting of 2-hydroxyethyl methacrylate (HEMA) onto the surface of stainless steel (SS) was explored by using 60Co-γ irradiation. The surface of SS was modified by coating of dopamine before radiation grafting. The grafting reaction was performed in a simultaneous irradiation condition. The chemical structures change of the surface before and after grafting was demonstrated by Fourier transform infrared (FTIR) spectrometer. The hydrophilicity of the samples was determined by water contact angle measurement in the comparison of the stainless steel in the conditions of pristine, dopamine coated and HEMA grafted. Surface morphology of the samples was characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The corrosion resistance properties of the samples were evaluated by Tafel polarization curve. The hemocompatibility of the samples were tested by platelet adhesion assay.

  6. Radiation-induced and RAFT-mediated grafting of poly(hydroxyethyl methacrylate) (PHEMA) from cellulose surfaces

    NASA Astrophysics Data System (ADS)

    Kodama, Yasko; Barsbay, Murat; Güven, Olgun

    2014-01-01

    This paper presents the results of RAFT mediated free-radical graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto cellulose fibers in a "grafting-from" approach under γ-irradiation. The effects of absorbed dose and monomer concentration on the graft ratios were investigated at different monomer (HEMA) to RAFT agent (cumyl dithiobenzoate, CDB) ratios. Cellulose-g-PHEMA copolymers with various graft ratios up to 92% (w/w) have been synthesized. The synthesized copolymers were characterized by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy, elemental analysis and scanning electron microscopy. The results of various techniques confirmed the existence of PHEMA in the copolymer composition.

  7. Methacrylate-based monolithic layers for planar chromatography of polymers.

    PubMed

    Maksimova, E F; Vlakh, E G; Tennikova, T B

    2011-04-29

    A series of macroporous monolithic methacrylate-based materials was synthesized by in situ free radical UV-initiated copolymerization of functional monomers, such as glycidyl methacrylate (GMA), butyl methacrylate (BuMA), 2-aminoethyl methacrylate (AEMA), 2-hydroxyethyl methacrylate (HEMA) and 2-cyanoethyl methacrylate (CEMA), with crosslinking agent, namely, ethylene glycol dimethacrylate (EDMA). The materials obtained were applied as the stationary phases in simple and robust technique - planar chromatography (PLC). The method of separation layer fabrication representing macroporous polymer monolith bound to the specially prepared glass surface was developed and optimized. The GMA-EDMA and BuMA-EDMA matrixes were successfully applied for the separation of low molecular weight compounds (the mixture of several dies), as well as poly(vinylpyrrolidone) and polystyrene homopolymers of different molecular weights using reversed-phase mechanism. The materials based on copolymers AEMA-HEMA-EDMA and CEMA-HEMA-EDMA were used for normal-phase PLC separation of 2,4-dinitrophenyl amino acids and polystyrene standards.

  8. Optical Characterization of the Ho^3+ Complex in HEMA

    NASA Astrophysics Data System (ADS)

    Rodriguez, Manuel, III; Sardar, Dhiraj; Nash, Kelly; Yow, Raylon; Gruber, John

    2007-10-01

    The spectroscopic properties of the Ho^3+ complex embedded in 2-hydroxyethyl methacrylate (HEMA) are investigated. The intensities of the room temperature absorption spectra of the Ho^3+(4f^10) transitions in Ho(NO3)3.5H2O:HEMA have been analyzed using the Judd-Ofelt (J-O) model to obtain the phenomenological intensity parameters, φ2, φ4, and φ6. These parameters are used to calculate the spontaneous emission probabilities, radiative lifetimes, and branching ratios of the Ho^3+ transitions from the upper multiplet manifolds to the corresponding lower-lying multiplet manifolds of ^2S+1LJ Ho^3+(4f^10), which include ^5G4+^3K7^(2), ^5G5, ^5G6+^5F1, ^5F2+^3K8^(2), ^5F3, ^5F4+^5S2, and ^5F5. The predicted room temperature fluorescence lifetime of ^5I7 to ^5I8 is about 0.5 ms, suggesting a reasonably strong interaction between the complex and the polymer. A comparative study of Ho^3+(4f^10) ions in different host materials suggests that Ho(NO3)3.5H2O:HEMA could be an excellent candidate for certain applications such as narrow band pass filters, especially in the visible-to-near infrared region of the spectrum.

  9. Atom Transfer Radical Copolymerization of Gradient Copolymers of HEMA/DMAEMA with Arbitrary Composition Profiles

    NASA Astrophysics Data System (ADS)

    Gallow, Keith; Loo, Yueh-Lin

    2009-03-01

    Gradient copolymers represent a new class of statistical copolymers where a non-uniform composition profile is controllably introduced along the length of the polymer chain. Gradient copolymers have thermal and mechanical properties that are different from random or block copolymers having the same average composition. Due to synthetic limitations, however, the introduction of arbitrary composition profiles remains challenging. Here, we demonstrate the ability to controllably introduce arbitrary composition profiles along copolymers of 2-hydroxyethyl methacrylate (HEMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) by atom transfer radical copolymerization in a semi-batch reactor. Using gas chromatography to monitor monomer consumption, we have constructed a kinetic model which we use as a basis to synthesize copolymers with linear and parabolic composition profiles. The overall DMAEMA content and molecular weight of these gradient copolymers were determined using nuclear magnetic resonance spectroscopy and size exclusion chromatography, respectively, and both show good agreement with our model's predictions.

  10. Facile Fabrication of Gradient Surface Based on (meth)acrylate Copolymer Films

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Yang, H.; Wen, X.-F.; Cheng, J.; Xiong, J.

    2016-08-01

    This paper describes a simple and economic approach for fabrication of surface wettability gradient on poly(butyl acrylate - methyl methacrylate) [P (BA-MMA)] and poly(butyl acrylate - methyl methacrylate - 2-hydroxyethyl methacrylate) [P (BA-MMA-HEMA)] films. The (meth)acrylate copolymer [including P (BA-MMA) and P (BA-MMA-HEMA)] films are hydrolyzed in an aqueous solution of NaOH and the transformation of surface chemical composition is achieved by hydrolysis in NaOH solution. The gradient wetting properties are generated based on different functional groups on the P (BA-MMA) and P (BA-MMA-HEMA) films. The effects of both the surface chemical and surface topography on wetting of the (meth)acrylate copolymer film are discussed. Surface chemical composition along the materials length is determined by XPS, and surface topography properties of the obtained gradient surfaces are analyzed by FESEM and AFM. Water contact angle system (WCAs) results show that the P (BA-MMA-HEMA) films provide a larger slope of the gradient wetting than P (BA-MMA). Moreover, this work demonstrates that the gradient concentration of chemical composition on the poly(meth) acrylate films is owing to the hydrolysis processes of ester group, and the hydrolysis reactions that have negligible influence on the surface morphology of the poly(meth) acrylate films coated on the glass slide. The gradient wettability surfaces may find broad applications in the field of polymer coating due to the compatibility of (meth) acrylate polymer.

  11. Cutaneous and inflammatory response to long-term percutaneous implants of sphere-templated porous/solid poly(HEMA) and silicone in mice.

    PubMed

    Fleckman, Philip; Usui, Marcia; Zhao, Ge; Underwood, Robert; Maginness, Max; Marshall, Andrew; Glaister, Christine; Ratner, Buddy; Olerud, John

    2012-05-01

    This study investigates mouse cutaneous responses to long-term percutaneously implanted rods surrounded by sphere-templated porous biomaterials engineered to mimic medical devices surrounded by a porous cuff. We hypothesized that keratinocytes would migrate through the pores and stop, permigrate, or marsupialize along the porous/solid interface. Porous/solid-core poly(2-hydroxyethyl methacrylate) [poly(HEMA)] and silicone rods were implanted in mice for 14 days, and for 1, 3, and 6 months. Implants with surrounding tissue were analyzed (immuno)histochemically by light microscopy. Poly(HEMA)/skin implants yielded better morphologic data than silicone implants. Keratinocytes at the poly(HEMA) interface migrated in two different directions. "Ventral" keratinocytes contiguous with the dermal-epidermal junction migrated into the outermost pores, forming an integrated collar surrounding the rods. "Dorsal" keratinocytes appearing to emanate from the differentiated epithelial layer, extended upward along and into the exterior portion of the rod, forming an integrated sheath. Leukocytes persisted in poly(HEMA) and silicone pores for the duration of the study. Vascular and collagen networks within the poly(HEMA) pores matured as a function of time up to 3-months implantation. Nerves were not observed within the pores. Poly(HEMA) underwent morphological changes by 6 months of implantation. Marsupialization, foreign body encapsulation, and infection were not observed in any implants.

  12. Encapsulation of polyphenols into pHEMA e-spun fibers and determination of their antioxidant activities.

    PubMed

    Ghitescu, Roxana-Elena; Popa, Ana-Maria; Popa, Valentin I; Rossi, Rene M; Fortunato, Giuseppino

    2015-10-15

    This study reports on the development of electrospun poly(2-hydroxyethyl methacrylate) (pHEMA) fibers loaded with synthetic and natural antioxidants in the form of selected types of polyphenols such as vanillic, gallic, syringic acids, catechin or natural spruce bark extract to investigate their release behavior in terms of antioxidant activities. Homogenous fiber morphologies were obtained at specified concentration ranges of pHEMA within the spinning solutions, exhibiting fiber diameters in the range from 0.5±0.1 μm to 1.9±0.5 μm. The addition of polyphenols resulted in an increase of fiber diameters with increasing concentration of additives. This is attributed to the effect of hydrogen bonding between the active ingredients and the polymeric matrix, increasing shear viscosities and thus hindering effective drawing processes during fiber formation. Polyphenol release measurement gave high release rates in a first phase followed by a smooth release at long term. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, used to monitor antioxidant activity, showed that polyphenols had retained their activity after incorporation into the pHEMA nanofibers. Furthermore, it was demonstrated that the encapsulation of polyphenols in pHEMA nanofibers can delay to a high extent their degradation induced by environmental factors.

  13. Synthesis and biodistribution of novel magnetic-poly(HEMA-APH) nanopolymer radiolabeled with iodine-131 and investigation its fate in vivo for cancer therapy

    NASA Astrophysics Data System (ADS)

    Avcıbaşı, Uğur; Avcıbaşı, Nesibe; Akalın, Hilmi Arkut; Ediz, Melis; Demiroğlu, Hasan; Gümüşer, Fikriye Gül; Özçalışkan, Emir; Türkcan, Ceren; Uygun, Deniz Aktaş; Akgöl, Sinan

    2013-10-01

    Herein, we investigated the biological uptake, distribution, and radiopharmaceutical potential of a novel molecule based on 2-hydroxyethyl methacrylate (HEMA) and anilinephtalein (APH) in the metabolism of Albino Wistar rats. In order to achieve this, we synthesized APH using organic synthesis methods and copolymerized APH with HEMA using a common polymerization method, surfactant-free emulsion polymerization. In the presence of Fe3O4 particles, we obtained a new generation magnetic-nano-scale polymer, magnetic-poly(HEMA-APH). This new molecule was chemically identified and approved by several characterization methods using Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, electron spin resonance, atomic force microscope, and Zeta particle-size analysis. To evaluate the biological activity in live metabolism and anti-cancer potential of mag-poly(HEMA-APH), molecule was radioiodinated by a widely used labeling technique, iodogen method, with a gamma diffuser radionuclide, 131I. Thin-layer radiochromatography experiments demonstrated that 131I binded to nanopolymer with the labeling yield of 90 %. Lipophilicity and stability experiments were conducted to determine the condition of cold and labeled mag-poly(HEMA-APH) in rat blood and lipid medium. Results demonstrated that radioiodinated molecule stayed as an intact complex in rat metabolism for 24 h and experimental lipophilicity was determined as 0.12 ± 0.02. In vivo results obtained by imaging and biological distribution experiments indicated that mag-poly(HEMA-APH) labeled with 131I [131I-mag-poly(HEMA-APH)] highly incorporated into tissues of the uterus, the ovarian, the prostate, and the lungs in rat metabolism. Based on these results, it may be evaluated that novel mag-poly(HEMA-APH) molecule labeled with 131I is a compound which has a significant potential for being used as an anti-cancer agent. Certain results can only be obtained whether this

  14. Effect of film thickness on the antifouling performance of poly(hydroxy-functional methacrylates) grafted surfaces.

    PubMed

    Zhao, Chao; Li, Lingyan; Wang, Qiuming; Yu, Qiuming; Zheng, Jie

    2011-04-19

    The development of nonfouling biomaterials to prevent nonspecific protein adsorption and cell/bacterial adhesion is critical for many biomedical applications, such as antithrombogenic implants and biosensors. In this work, we polymerize two types of hydroxy-functional methacrylates monomers of 2-hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPMA) into polymer brushes on the gold substrate via surface-initiated atom transfer radical polymerization (SI-ATRP). We systematically examine the effect of the film thickness of polyHEMA and polyHPMA brushes on their antifouling performance in a wide range of biological media including single-protein solution, both diluted and undiluted human blood serum and plasma, and bacteria culture. Surface plasmon resonance (SPR) results show a strong correlation between antifouling property and film thickness. Too thin or too thick polymer brushes lead to large protein adsorption. Surfaces with the appropriate film thickness of ∼25-45 nm for polyHPMA and ∼20-45 nm for polyHEMA can achieve almost zero protein adsorption (<0.3 ng/cm(2)) from single-protein solution and diluted human blood plasma and serum. For undiluted human blood serum and plasma, polyHEMA brushes at a film thickness of ∼20-30 nm adsorb only ∼3.0 and ∼3.5 ng/cm(2) proteins, respectively, while polyHPMA brushes at a film thickness of ∼30 nm adsorb more proteins of ∼13.5 and ∼50.0 ng/cm(2), respectively. Moreover, both polyHEMA and polyHPMA brushes with optimal film thickness exhibit very low bacteria adhesion. The excellent antifouling ability and long-term stability of polyHEMA and polyHPMA brushes make them, especially for polyHEMA, effective and stable antifouling materials for usage in blood-contacting devices.

  15. Preclinical Evaluation of Poly(HEMA-co-acrylamide) Hydrogels Encapsulating Glucose Oxidase and Palladium Benzoporphyrin as Fully Implantable Glucose Sensors

    PubMed Central

    Unruh, Rachel M.; Roberts, Jason R.; Nichols, Scott P.; Gamsey, Soya; Wisniewski, Natalie A.; McShane, Michael J.

    2015-01-01

    Background: Continuous glucose monitors (CGMs) require percutaneous wire probes to monitor glucose. Sensors based on luminescent hydrogels are being explored as fully implantable alternatives to traditional CGMs. Our previous work investigated hydrogel matrices functionalized with enzymes and oxygen-quenched phosphors, demonstrating sensitivity to glucose, range of response, and biofouling strongly depend on the matrix material. Here, we further investigate the effect of matrix composition on overall performance in vitro and in vivo. Methods: Sensors based on three hydrogels, a poly(2-hydroxyethyl methacrylate) (pHEMA) homopolymer and 2 poly(2-hydroxyethyl methacrylate-co-acrylamide) (pHEMA-co-AAm) copolymers, were compared. These were used to entrap glucose oxidase (GOx), catalase, and an oxygen-sensitive benzoporphyrin phosphor. All sensor formulations were evaluated for glucose response and stability at physiological temperatures. Selected sensors were then evaluated as implanted sensors in a porcine model challenged with glucose and insulin. The animal protocol used in this study was approved by an IACUC committee at Texas A&M University. Results: PHEMA-co-AAm copolymer hydrogels (75:25 HEMA:AAm) yielded the most even GOx and dye dispersion throughout the hydrogel matrix and best preserved GOx apparent activity. In response to in vitro glucose challenges, this formulation exhibited a dynamic range of 12-167 mg/dL, a sensitivity of 1.44 ± 0.46 µs/(mg/dL), and tracked closely with reference capillary blood glucose values in vivo. Conclusions: The hydrogel-based sensors exhibited excellent sensitivity and sufficiently rapid response to the glucose levels achieved in vivo, proving feasibility of these materials for use in real-time glucose tracking. Extending the dynamic range and assessing long-term effects in vivo are ongoing efforts. PMID:26085565

  16. Biodegradable HEMA-based hydrogels with enhanced mechanical properties.

    PubMed

    Moghadam, Mohamadreza Nassajian; Pioletti, Dominique P

    2016-08-01

    Hydrogels are widely used in the biomedical field. Their main purposes are either to deliver biological active agents or to temporarily fill a defect until they degrade and are followed by new host tissue formation. However, for this latter application, biodegradable hydrogels are usually not capable to sustain any significant load. The development of biodegradable hydrogels presenting load-bearing capabilities would open new possibilities to utilize this class of material in the biomedical field. In this work, an original formulation of biodegradable photo-crosslinked hydrogels based on hydroxyethyl methacrylate (HEMA) is presented. The hydrogels consist of short-length poly(2-hydroxyethyl methacrylate) (PHEMA) chains in a star shape structure, obtained by introducing a tetra-functional chain transfer agent in the backbone of the hydrogels. They are cross-linked with a biodegradable N,O-dimethacryloyl hydroxylamine (DMHA) molecule sensitive to hydrolytic cleavage. We characterized the degradation properties of these hydrogels submitted to mechanical loadings. We showed that the developed hydrogels undergo long-term degradation and specially meet the two essential requirements of a biodegradable hydrogel suitable for load bearing applications: enhanced mechanical properties and low molecular weight degradation products. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1161-1169, 2016.

  17. NMR Relaxation and Diffusion in Polymerized Microemulsions of HEMA and MMA

    NASA Astrophysics Data System (ADS)

    von Meerwall, E.; Chandran, S.; Slivka, J.; Lopina, S.; Cheung, M.

    2002-10-01

    In an effort to develop a class of materials for use in controlled drug delivery via implantation, we have used proton NMR T2 relaxation and pulsed-field-gradient diffusion (D) measurements to study bicontinuous microemulsions formed with methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), polymerized and crosslinked with 4 wt. percent ethylene glycol dimethacrylate, in the presence of water containing ten percent surfactant, either the inert sodium alkyl sulfate or the polymerizable TREM-LF-40. Measurements were made at 50 deg. C over the full two-phase range (e. g., 30 to 96 percent aqueous, depending on HEMA/MMA ratio). We identify a trimodal T2 spectrum with components attributable to the semi-glassy network, adsorbed surfactant and ingested water, and the interstitial aqueous phase. In the latter, two distinct D rates are due to free water and dissolved surfactant; specimens are permeable to both. Component intensity ratios are non-monotonic in aqueous content. Results suggest a wide range of pore sizes and complex interactions between the mobile molecules and the network surfaces, pores, and swellable bulk. Surfactant reactivity seems to play a minor role. Results of other characterizations complement and support these findings.

  18. Effect of gamma radiation on the mechanical and barrier properties of HEMA grafted chitosan-based films

    NASA Astrophysics Data System (ADS)

    Khan, Avik; Huq, Tanzina; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Lacroix, Monique

    2012-08-01

    Chitosan films were prepared by dissolving 1% (w/v) chitosan powder in 2% (w/v) aqueous acetic acid solution. Chitosan films were prepared by solution casting. The values of puncture strength (PS), viscoelasticity coefficient and water vapor permeability (WVP) of the films were found to be 565 N/mm, 35%, and 3.30 g mm/m2 day kPa, respectively. Chitosan solution was exposed to gamma irradiation (0.1-5 kGy) and it was revealed that PS values were reduced significantly (p≤0.05) after 1 kGy dose and it was not possible to form films after 5 kGy. Monomer, 2-hydroxyethyl methacrylate (HEMA) solution (0.1-1%, w/v) was incorporated into the chitosan solution and the formulation was exposed to gamma irradiation (0.3 kGy). A 0.1% (w/v) HEMA concentration at 0.3 kGy dose was found optimal-based on PS values for chitosan grafting. Then radiation dose (0.1-5 kGy) was optimized for HEMA grafting. The highest PS values (672 N/mm) were found at 0.7 kGy. The WVP of the grafted films improved significantly (p≤0.05) with the rise of radiation dose.

  19. Novel hydrogel membrane based on copoly(hydroxyethyl methacrylate/p-vinylbenzyl-poly(ethylene oxide)) for biomedical applications: properties and drug release characteristics.

    PubMed

    Arica, M Yakup; Bayramoglu, Gülay; Arica, Betül; Yalçin, Emine; Ito, Koichi; Yagci, Yusuf

    2005-10-20

    The aim of this study was to synthesize and characterize a novel biocompatible polymeric membrane system and demonstrate its potential use in various biomedical applications. Synthetic hydrogels based on poly(hydroxyethyl methacrylate), poly(HEMA), have been widely studied and used in biomedical fields. A novel copolymer hydrogel was prepared in the membrane form using 2-hydroxyethyl methacrylate monomer (HEMA) and a macromonomer p-vinylbenzyl-poly(ethylene oxide) (V-PEO) via photoinitiated polymerization. A series of poly(HEMA/V-PEO) copolymer membranes with different compositions was prepared. The membranes were characterized using infrared, thermal and SEM analysis. The thermal stabilities of the copolymer membranes were found to be lowered by an increase in the ratio of macromonomer (V-PEO) in the membrane structure. Because of the incorporation of PEO segments, the copolymers exhibited significantly higher hydrophilic surface properties than pure poly(HEMA), as demonstrated by contact angle measurements. Equilibrium swelling studies were conducted to investigate the swelling behavior of the membranes. The equilibrium water uptake was reached in about 4 h. Moreover, the blood protein adsorption and platelet adhesion were significantly reduced on the surface of the PEO containing copolymer membranes compared to control pure poly(HEMA). Drug release experiments were performed in a continuous release system using model drug (vancomycin) loaded copoly(HEMA/V-PEO) membranes. A specific poly(HEMA/V-PEO) membrane formulation possessing the highest PEO content (with a HEMA:V-PEO (mmol:mmol) feed ratio of 112:1 and loaded with 40 mg antibiotic/g polymer) released about 81% of the total loaded drug in 24 h at pH 7.4. This membrane composition provided the best results and can be considered as a potential candidate for a transdermal antibiotic carrier and various biomedical and biotechnological applications.

  20. Modulated release of cyclosporine from soluble vinyl pyrrolidone--hydroxyethyl methacrylate copolymer hydrogels. A correlation of 'in vitro' and 'in vivo' experiments.

    PubMed

    Gallardo, A; Fernández, F; Cifuentes, A; Díez-Masa, J C; Bermejo, P; Rebuelta, M; López-Bravo, A; San Román, J

    2001-05-14

    Soluble, uncrosslinked and high molecular weight copolymers of vinylpyrrolidone, VP, with 2-hydroxyethyl methacrylate, HEMA, prepared by free radical copolymerization, are proposed as supports for the modulated release of the immunosuppressor cyclosporine. Two copolymeric systems with copolymer compositions f(VP)=0.52 (namely VP--HEMA 60--40) and 0.42 (VP--HEMA 40--60) have been prepared and tested in vitro and in vivo using rats as animal model. Micellar electrokinetic capillary chromatography, MEKC, has been used for the simultaneous detection of the polymer reabsorption and the drug release for the in vitro experiments. The composition and microstructural distribution of the copolymer system controls the solubilization rate which modulates the in vitro release of the drug (with time profiles from a few days to several weeks for the VP--HEMA 60--40 and 40--60, respectively) and the in vivo response that correlates with the previous in vitro results: the more hydrophobic implant (VP--HEMA 40--60) reverts the immune response more slowly (2--4 weeks) compared to the more hydrophilic one (VP--HEMA 60--40, 1--2 weeks).

  1. Preparation and in vitro evaluation of topical formulations based on polystyrene-poly-2-hydroxyl methacrylate nanoparticles.

    PubMed

    Wu, Xiao; Griffin, Peter; Price, Gareth J; Guy, Richard H

    2009-01-01

    The skin disposition of topically applied nanoparticles with varying degrees of hydrophobicity, composed of different proportions of polystyrene (PS) and poly-(2-hydroxyethyl methacrylate) (HEMA), and of an associated, model "active" (Nile Red), was investigated. PS-HEMA copolymer nanoparticles were fluorescently labeled, via the covalent incorporation of a small quantity of fluorescein methacrylate, and characterized by dynamic light scattering, transmission electron microscopy and NMR. The fluorophore, Nile Red, was dispersed into the nanoparticles and its loading was determined by ultracentrifugation. Skin uptake was assessed in vitro following a 6 h application of the nanoparticle formulation, via stratum corneum (SC) tape-stripping and confocal microscopy. Nanoparticle diameters were below 100 nm. Progressive introduction of HEMA decreased particle hydrophobicity and reduced Nile Red loading. Uptake of Nile Red into the skin, as assessed both by the amounts extracted from the SC and by confocal microscopy, decreased as the percentage HEMA increased. Confocal microscopy confirmed that nanoparticles could not move beyond the superficial SC, but did show affinity for hair follicle openings. In conclusion, the loading of a lipophilic "active" into nanoparticles, and its subsequent release when these formulations are applied topically, are sensitive to the composition and relative hydrophobicity of the carrier.

  2. Cytotoxic effects of acrylates and methacrylates: relationships of monomer structures and cytotoxicity.

    PubMed

    Yoshii, E

    1997-12-15

    Thirty-nine acrylates and methacrylates that had been used in dental resin materials were evaluated by a cytotoxicity test, and the relationships between their structures and cytotoxicity were studied to predict cytotoxic levels of dental resin materials in order to develop new low-toxic resin materials. All the acrylates evaluated were more toxic than corresponding methacrylates. In both the acrylates and methacrylates, a hydroxyl group seemed to enhance cytotoxicity. Dimethacrylates with 14 or fewer oxyethylene chains showed similar cytotoxicity while dimethacrylates with 23 oxyethylene chains showed lower cytotoxicity. The cytotoxicity ranking of monomers widely used in dental resin materials was bisphenol A bis 2-hydroxypropyl methacrylate (bisGMA) > urethane dimethacrylate (UDMA) > triethyleneglycol dimethacrylate (3G) > 2-hydroxyethyl methacrylate (HEMA) > methyl methacrylate (MMA). In acrylates, methacrylates, and ethylmethacrylates with either substituents, the lipophilicity of substituents affected their cytotoxicity, and an inverse correlation between IC50 and logP was observed. These results will be useful in developing new resin materials with low toxic monomer compositions.

  3. Improvement of the mechanical and barrier properties of methylcellulose-based films by treatment with HEMA and silane monomers under gamma radiation

    NASA Astrophysics Data System (ADS)

    Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Safrany, Agnes; Lacroix, Monique

    2012-08-01

    Methylcellulose (MC)-based films were prepared by casting from its 1% aqueous solution containing 0.5% vegetable oil, 0.25% glycerol and 0.025% Tween®-80. Puncture strength (PS), puncture deformation (PD) and water vapor permeability (WVP) of the films were found to be 147 N/mm, 3.46 mm, and 6.34 g mm/m2 day kPa, respectively. The monomer, 2-hydroxyethyl methacrylate (HEMA) (0.1-1%, w/w) was incorporated into the MC-based solution and films were prepared by casting. Films were then exposed to gamma radiation (5-25 kGy) and it revealed that 1% HEMA containing films showed the highest PS values (282 N/mm at 10 kGy). Silane monomer (3-aminopropyl tri-ethoxy silane) (0.1-1%, w/w) was also added into the MC-based films and were found to improve the strength of the films significantly. In comparison between HEMA and silane treatment onto MC-based films, it was observed that silane performed better strength and barrier properties. Surface morphology of the monomer treated films was examined by scanning electron microscopy and suggested better appearance than MC-based film.

  4. NSAIDs bound to methacrylic carriers: microstructural characterization and in vitro release analysis.

    PubMed

    Gallardo, A; Parejo, C; San Román, J

    2001-03-12

    Chemically controlled drug delivery systems or 'polymeric drugs' based on copolymers of 2-hydroxyethyl methacrylate, HEMA, and five methacrylic derivatives which incorporate ibuprofen or ketoprofen in their chemical structure by means of labile ester bonds, MAI, MAK, MAEK, MEI and MEK, have been prepared by free radical polymerization in solution at 50 degrees C. Three different spacers have been incorporated to the monomer structure: an aromatic amide, an aliphatic ester and a combined aromatic amide/aliphatic ester. Copolymerization reactions of the methacrylamide derivatives with HEMA follow the terminal model with reactivity ratio values, determined by the Tidwell and Mortimer (J. Polym. Sci. A 1965;3:369-378) non-linear least-squares treatment, of r(MAI)=0.38, r(HEMA)=1.69; r(MAK)=0.30, r(HEMA)=0.48; and r(MAEK)=0.66, r(HEMA)=2.85. From these values and considering that the methacrylates MEI and MEK are structurally related to HEMA, the microstructural analysis give us a random distribution of the monomeric units. The HEMA-rich copolymers, used for the in vitro experiments, showed a very high population of sequences with the active residue isolated by HEMA units. The in vitro release experiments were carried out at pH 7.4 and 9, using six different compositions for each copolymer system (1, 2.5, 5, 10, 20 and 30 wt% of the active acrylic monomer). The results show a controlled release in terms of weeks with very different profiles which depend on the type of spacer (the aromatic ester is more susceptible to hydrolysis than the aliphatic one), drug (ketoprofen release rate is higher than the ibuprofen one), composition of the copolymer (as a general rule, the release rate increases with the content of the attached drug until some composition where this effect is reverted because of the global increase in hydrophobicity) and pH (the release rate is noticeably higher in a strong basic medium, pH 9).

  5. Sensitive and rapid detection of aflatoxin M1 in milk utilizing enhanced SPR and p(HEMA) brushes.

    PubMed

    Karczmarczyk, Aleksandra; Dubiak-Szepietowska, Monika; Vorobii, Mariia; Rodriguez-Emmenegger, Cesar; Dostálek, Jakub; Feller, Karl-Heinz

    2016-07-15

    The rapid and sensitive detection of aflatoxin M1 (AFM1) in milk by using surface plasmon resonance (SPR) biosensor is reported. This low molecular weight mycotoxin is analyzed using an indirect competitive immunoassay that is amplified by secondary antibodies conjugated with Au nanoparticles. In order to prevent fouling on the sensor surface by the constituents present in analyzed milk samples, an interface with poly(2-hydroxyethyl methacrylate) p(HEMA) brush was employed. The study presents a comparison of performance characteristics of p(HEMA)-based sensor with a regularly used polyethylene glycol-based architecture relying on mixed thiol self-assembled monolayer. Both sensors are characterized in terms of surface mass density of immobilized AFM1 conjugate as well as affinity bound primary and secondary antibodies. The efficiency of the amplification strategy based on Au nanoparticle is discussed. The biosensor allowed for highly sensitive detection of AFM1 in milk with a limit of detection (LOD) as low as 18pgmL(-1) with the analysis time of 55min.

  6. Radiation-induced change of optical property of hydroxypropyl cellulose hydrogel containing methacrylate compounds: As a basis for development of a new type of radiation dosimeter

    NASA Astrophysics Data System (ADS)

    Yamashita, Shinichi; Hiroki, Akihiro; Taguchi, Mitsumasa

    2014-08-01

    Hydrogels with matrix of a cellulose derivative, hydrogel of hydroxpropyl cellulose (HPC), containing two of methacrylate compounds (2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) dimethacrylate (9G)) were irradiated with 60Co γ-rays. The gels become white with irradiation, and thus, could be candidates of a new type of radiation dosimeter utilized in radiation therapy because the gels become white with irradiation and can be confirmed directly by human eyes even at low doses of 1-2 Gy. Radiation-induced change of optical properties, haze value and UV-vis absorption spectrum, of the irradiated gels was measured. Dose response of the white turbidity appearance was different for different compositions of the methacrylate compounds as well as for different dose rates. The degree of the radiation-induced white turbidity was quantified by measuring haze value, showing linear dose response in low dose region (<2 Gy). We also analyzed the gels with a UV-vis spectrometer and HEMA- and 9G-rich gels gave different spectral shapes, indicating that there are at least two mechanisms leading to the white turbidity. In addition, dose rate dependence was smaller for 9G-rich gels than HEMA-rich gels in the range of 0.015-1.5 Gy/min.

  7. 2-hydroxyethyl metahcrylate/gelatin based superporous hydrogels for tissue regeneration

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida Lj.; Babić, Marija M.; Vuković, Jovana S.; Perišić, Marija D.; Filipović, Vuk V.; Davidović, Sladjana Z.; Filipović, Jovanka M.

    2016-05-01

    In this study, superporous hydrogels were synthesized by free radical polymerization of 2-hydroxyethyl methacrylate without and in the presence of gelatin. Highly porous hydrogel structures were obtained by two different techniques: using a gas blowing agent, sodium bicarbonate, and a cryogenic treatment followed by freeze-drying. After the gel synthesis, gelatin molecules were covalently immobilised onto PHEMA via glytaraldehyde activation. All samples were characterized for morphological, mechanical, swelling and antibacterial properties. The results obtained show that samples with gelatin show better properties in comparison with PHEMA samples, which make these materials highly attractive for developing hydrogel scaffolds for tissue regeneration.

  8. The Competing Effects of Hyaluronic and Methacrylic Acid in Model Contact Lenses.

    PubMed

    Weeks, Andrea; Subbaraman, Lakshman N; Jones, Lyndon; Sheardown, Heather

    2012-01-01

    The aim of this study was to determine the influence of hyaluronic acid (HA) on lysozyme sorption in model contact lenses containing varying amounts of methacrylic acid (MAA). One model conventional hydrogel (poly(2-hydroxyethyl methacrylate) (pHEMA)) and two model silicone hydrogels (pHEMA, methacryloxypropyltris(trimethylsiloxy)silane (pHEMA TRIS) and N,N-dimethylacrylamide, TRIS (DMAA TRIS)) lens materials were prepared with and without MAA at two different concentrations (1.7 and 5%). HA, along with dendrimers, was loaded into these model contact lens materials and then cross-linked with 1-ethyl-3-(3-dimethylamino propyl)-carbodiimide (EDC). Equilibrium water content (EWC), advancing water contact angle and lysozyme sorption on these lens materials were investigated. In the HA-containing materials, the presence (P < 0.05) and amount (P < 0.05) of MAA increased the EWC of the materials. For most materials, addition of MAA reduced the advancing contact angles (P < 0.05) and for all the materials, the addition of HA further improved hydrophilicity (P < 0.05). For the non-HA containing hydrogels, the presence (P < 0.05) and amount (P < 0.05) of MAA increased lysozyme sorption. The presence of HA decreased lysozyme sorption for all materials (P < 0.05). MAA appears to work synergistically with HA to increase the EWC in addition to improving the hydrophilicity of model pHEMA-based and silicone hydrogel contact lens materials. Hydrogel materials that contain HA have tremendous potential as hydrophilic, protein-resistant contact lens materials.

  9. Water-soluble drug partitioning and adsorption in HEMA/MAA hydrogels.

    PubMed

    Dursch, Thomas J; Taylor, Nicole O; Liu, David E; Wu, Rong Y; Prausnitz, John M; Radke, Clayton J

    2014-01-01

    Two-photon confocal microscopy and back extraction with UV/Vis-absorption spectrophotometry quantify equilibrium partition coefficients, k, for six prototypical drugs in five soft-contact-lens-material hydrogels over a range of water contents from 40 to 92%. Partition coefficients were obtained for acetazolamide, caffeine, hydrocortisone, Oregon Green 488, sodium fluorescein, and theophylline in 2-hydroxyethyl methacrylate/methacrylic acid (HEMA/MAA, pKa≈5.2) copolymer hydrogels as functions of composition, aqueous pH (2 and 7.4), and salinity. At pH 2, the hydrogels are nonionic, whereas at pH 7.4, hydrogels are anionic due to MAA ionization. Solute adsorption on and nonspecific electrostatic interaction with the polymer matrix are pronounced. To express deviation from ideal partitioning, we define an enhancement or exclusion factor, E ≡ k/φ1, where φ1 is hydrogel water volume fraction. All solutes exhibit E > 1 in 100 wt % HEMA hydrogels owing to strong specific adsorption to HEMA strands. For all solutes, E significantly decreases upon incorporation of anionic MAA into the hydrogel due to lack of adsorption onto charged MAA moieties. For dianionic sodium fluorescein and Oregon Green 488, and partially ionized monoanionic acetazolamide at pH 7.4, however, the decrease in E is more severe than that for similar-sized nonionic solutes. Conversely, at pH 2, E generally increases with addition of the nonionic MAA copolymer due to strong preferential adsorption to the uncharged carboxylic-acid group of MAA. For all cases, we quantitatively predict enhancement factors for the six drugs using only independently obtained parameters. In dilute solution for solute i, Ei is conveniently expressed as a product of individual enhancement factors for size exclusion (Ei(ex)), electrostatic interaction (Ei(el)), and specific adsorption (Ei(ad)):Ei≡Ei(ex)Ei(el)Ei(ad). To obtain the individual enhancement factors, we employ an extended Ogston mesh-size distribution for Ei

  10. UV-Curable Polyurethane-Methacrylate Co-Networks and Interpenetrating Networks

    DTIC Science & Technology

    1989-05-30

    were: methyl methacrylate (MMA), ethyl methacrylate (EMA), hydroxyethyl methacrylate ( HEMA ), butyl methacrylate (BMA), lauryl methacrylate (LMA), and...ACCESSION NO. 11. TITLE (include Security Classification) UV’V-Curable Polyurethane- Methacrylate Co-Networks and Interpenetrating Networks 12. PERSONAL...by block number 4 Castor oil was reacted in varying ratios with 6-isocyanatoethyl methacrylate to form a liquid urethane- methacrylate prepolymer. This

  11. Synthesis of polymer materials by low energy electron beam. IV. EB-polymerized urethane-acrylate, -methacrylate and -acrylamide

    NASA Astrophysics Data System (ADS)

    Ando, Masayuki; Uryu, Toshiyuki

    The structure and properties before and after electron beam (EB) irradiation were investigated using urethane prepolymers with different terminal groups of 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA) and N-hydroxymethyl acrylamide (HMAAm). The prepolymers were synthesized by reaction of HEA, HEMA and HMAAm with the isocyanate-capped intermediate, which was obtained by reaction of poly(butylene adipate)diol (PBAD) with 4,4'-diphenylmethane diisocyanate. The resulting urethane-acrylate (UA-251M), -methacrylate (UMA-251M) and -acrylamide (UNAA-251M) had the crystallinity arising from PBAD moieties, and UA-251M and UMA-251M had higher crystallinity than UNAA-251M. IR results indicated that UNAA-251M was larger in the fraction of free NH stretching absorption than UA-251M and UMA-251M regardless of the number of NH group per a molecule. Accordingly, it was assumed that the difference in crystallinity was attributed to the polarity of terminal group. Hence, the rate of gel formation for UA-251M and UMA-251M was higher than that of UNAA-251M. The crystallinity based on PBAD of the prepolymers was remained also after EB irradiation. Spherulitic texture was observed on the EB-polymerized gel film surfaces for UA-251M and UMA-251M, while it was almost destroyed for UNAA-251M. Mechanical properties of UA-251M and UMA-251M gel films were much superior to those of UNAA-251M gel film according to the phase structure. Especially, UMA-251M gel film represented most excellent mechanical properties. Schematic models of the phase structure for UA-251M, UMA-251M and UNAA-251M were suggested from all experimental results.

  12. Peptide surface modification of P(HEMA-co-MMA)-b-PIB-b-P(HEMA-co-MMA) block copolymers.

    PubMed

    Ojha, Umaprasana; Feng, Dingsong; Chandekar, Amol; Whitten, James E; Faust, Rudolf

    2009-06-02

    Peptide surface modification of poly[(methyl methacrylate-co-hydroxyethyl methacrylate)-b-isobutylene-b-(methyl methacrylate-co-hydroxyethyl methacrylate)] P(MMA-co-HEMA)-b-PIB-b-P(MMA-co-HEMA) triblock copolymers with different HEMA/MMA ratios has been accomplished using an efficient synthetic procedure. The triblock copolymers were reacted with 4-fluorobenzenesulfonyl chloride (fosyl chloride) in pyridine to obtain the activated polymers [poly{(methyl methacrylate-co-fosyloxyethyl methacrylate)-b-isobutylene-b-(methyl methacrylate-co-fosyloxyethyl methacrylate)}] P(MMA-co-FEMA)-b-PIB-b-P(MMA-co-FEMA), with an activating efficiency of 80-90%. The resulting polymers were soluble in chloroform, and their solutions were used to coat thin uniform films with a predetermined thickness on smooth steel surfaces. The presence of reactive activating groups on the film surface was confirmed by X-ray photoelectron spectroscopy (XPS), dye labeling, and confocal laser scanning microscopic studies. Activation of the triblock copolymer films was also achieved under heterogeneous conditions in polar (acetonitrile) and nonpolar (hexanes) media. The extent of activation was controlled by varying the dipping time and polarity of the medium. Peptide attachment was accomplished by immersing the coated steel strips into aqueous buffer solution of Gly-Gly or GYIGSR. XPS and solubility studies revealed successful attachment of peptides to the polymer surface. Virtually all remaining activating groups were successfully replaced in the subsequent step by a treatment with Tris(hydroxymethyl)amino methane in a buffered methanol/water mixture.

  13. Designing novel macroporous composite hydrogels based on methacrylic acid copolymers and chitosan and in vitro assessment of lysozyme controlled delivery.

    PubMed

    Dragan, Ecaterina Stela; Cocarta, Ana Irina; Gierszewska, Magdalena

    2016-03-01

    Designing structure and morphology of macroporous hydrogels is crucial for their applications in controlled release systems of macromolecular drugs. Macroporous hydrogels, consisting of methacrylic acid (MAA) and either acryl amide (AAm) or 2-hydroxyethyl methacrylate (HEMA) (1st network), were prepared for this purpose by cryogelation (single network cryogels, SNCs). Macroporous interpenetrating polymer network (IPN) hydrogel composites were then prepared by a sequential strategy, the 2nd network consisting of chitosan (CS) cross-linked with poly(ethyleneglycol) diglycidyl ether (PEGDGE) being generated by the sorption of a CS and PEGDGE mixture in the 1st network followed by cross-linking. A strong difference in the behavior of SNCs and IPN hydrogel composites was found during the loading and release of lysozyme (LYS) used as macromolecular drug model. Thus, while the amount of LYS loaded on SNCs was higher than that loaded on the IPNs, the release of LYS from SNCs occurred at pH 2, when the ratio between MAA and AAm was 50:50, and only at pH 1 when the ratio between MAA and AAm was 70:30. The 2nd network led to the decrease of the pore size of the IPNs, mainly when the initial concentration of monomers was 10wt/v%, but the presence of CS facilitates the LYS release from IPNs, mainly at a concentration of monomer of 5wt/v%, and when HEMA was used as nonionic comonomer.

  14. Wrinkle formation in a polymeric drug coating deposited via initiated chemical vapor deposition† †Electronic supplementary information (ESI) available: FT-IR spectrum of the pHEMA film, AFM micrographs for the 200 nm pHEMA film on different scales. See DOI: 10.1039/c6sm01919f Click here for additional data file.

    PubMed Central

    Christian, Paul; Ehmann, Heike M. A.; Werzer, Oliver

    2016-01-01

    Polymer encapsulation of drugs is conventionally used as a strategy for controlled delivery and enhanced stability. In this work, a novel encapsulation approach is demonstrated, in which the organic molecule clotrimazole is enclosed into wrinkles of defined sizes. Having defined wrinkles at the drug/encapsulant interface, the contact between the encapsulating polymer and the drug can be improved. In addition, this can also allow for some control on the drug delivery as the available surface area changes with the wrinkle size. For this purpose, thin films of clotrimazole were deposited onto silica substrates and were then encapsulated by crosslinked poly(2-hydroxyethyl methacrylate) (pHEMA) via initiated chemical vapor deposition (iCVD). The thickness and the solid state (crystalline or amorphous) of the clotrimazole layer were varied so that the conditions under which surface wrinkles emerge can be determined. A (critical) clotrimazole thickness of 76.6 nm was found necessary to induce wrinkles, whereby the wrinkle size is directly proportional to the thickness of the amorphous clotrimazole. When the pHEMA was deposited on top of crystalline clotrimazole instead, wrinkling was absent. The wrinkling effect can be understood in terms of elastic mismatch between the relatively rigid pHEMA film and the drug layer. In the case of amorphous clotrimazole, the relatively soft drug layer causes a large mismatch resulting in a sufficient driving force for wrinkle formation. Instead, the increased elastic modulus of crystalline clotrimazole reduces the elastic mismatch between drug and polymer, so that wrinkles do not form. PMID:27841419

  15. N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine, a new urinary metabolite of acrylonitrile and oxiranecarbonitrile.

    PubMed

    Linhart, I; Smejkal, J; Novák, J

    1988-01-01

    Two mercapturic acids, i.e., N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (CHEMA) and N-acetyl-S-(2-hydroxyethyl)-L-cysteine (HEMA), were isolated from the urine of rats dosed with four successive doses of oxiranecarbonitrile (glycidonitrile, GN), 5 mg/kg, a reactive metabolic intermediate of acrylonitrile (AN). GC-MS analysis of methylated urine extracts from both AN- and GN-dosed rats showed another mercapturate which was identified as N-acetyl-S-(1-cyanoethenyl)-L-cysteine (1-CEMA) methyl ester using an authentic reference sample. The mass spectrum of this compound was very similar to that of a methylated metabolite of AN tentatively identified by Langvardt et al. (1980) as N-acetyl-3-carboxy-5-cyanothiazane (ACCT). In contrast, no ACCT was found in rats dosed with either GN or AN. Hence, there is no evidence for the formation of ACCT or its isomers in rats dosed with AN or GN. The methyl ester of 1-CEMA is formed artificially by dehydration of CHEMA methyl ester in the injector of the gas chromatograph.

  16. A nonviral pHEMA+chitosan nanosphere-mediated high-efficiency gene delivery system.

    PubMed

    Eroglu, Erdal; Tiwari, Pooja M; Waffo, Alain B; Miller, Michael E; Vig, Komal; Dennis, Vida A; Singh, Shree R

    2013-01-01

    The transport of DNA into eukaryotic cells is minimal because of the cell membrane barrier, and this limits the application of DNA vaccines, gene silencing, and gene therapy. Several available transfection reagents and techniques have been used to circumvent this problem. Alternatively, nonviral nanoscale vectors have been shown to bypass the eukaryotic cell membrane. In the present work, we developed a unique nanomaterial, pHEMA+chitosan nanospheres (PCNSs), which consisted of poly(2-hydroxyethyl methacrylate) nanospheres surrounded by a chitosan cationic shell, and we used this for encapsulation of a respiratory syncytial virus (RSV)-F gene construct (a model for a DNA vaccine). The new nanomaterial was capable of transfecting various eukaryotic cell lines without the use of a commercial transfection reagent. Using transmission electron microscopy, (TEM), fluorescence activated cell sorting (FACS), and immunofluorescence, we clearly demonstrated that the positively charged PCNSs were able to bind to the negatively charged cell membrane and were taken up by endocytosis, in Cos-7 cells. Using quantitative polymerase chain reaction (qPCR), we also evaluated the efficiency of transfection achieved with PCNSs and without the use of a liposomal-based transfection mediator, in Cos-7, HEp-2, and Vero cells. To assess the transfection efficiency of the PCNSs in vivo, these novel nanomaterials containing RSV-F gene were injected intramuscularly into BALB/c mice, resulting in high copy number of the transgene. In this study, we report, for the first time, the application of the PCNSs as a nanovehicle for gene delivery in vitro and in vivo.

  17. A nonviral pHEMA+chitosan nanosphere-mediated high-efficiency gene delivery system

    PubMed Central

    Eroglu, Erdal; Tiwari, Pooja M; Waffo, Alain B; Miller, Michael E; Vig, Komal; Dennis, Vida A; Singh, Shree R

    2013-01-01

    The transport of DNA into eukaryotic cells is minimal because of the cell membrane barrier, and this limits the application of DNA vaccines, gene silencing, and gene therapy. Several available transfection reagents and techniques have been used to circumvent this problem. Alternatively, nonviral nanoscale vectors have been shown to bypass the eukaryotic cell membrane. In the present work, we developed a unique nanomaterial, pHEMA+chitosan nanospheres (PCNSs), which consisted of poly(2-hydroxyethyl methacrylate) nanospheres surrounded by a chitosan cationic shell, and we used this for encapsulation of a respiratory syncytial virus (RSV)-F gene construct (a model for a DNA vaccine). The new nanomaterial was capable of transfecting various eukaryotic cell lines without the use of a commercial transfection reagent. Using transmission electron microscopy, (TEM), fluorescence activated cell sorting (FACS), and immunofluorescence, we clearly demonstrated that the positively charged PCNSs were able to bind to the negatively charged cell membrane and were taken up by endocytosis, in Cos-7 cells. Using quantitative polymerase chain reaction (qPCR), we also evaluated the efficiency of transfection achieved with PCNSs and without the use of a liposomal-based transfection mediator, in Cos-7, HEp-2, and Vero cells. To assess the transfection efficiency of the PCNSs in vivo, these novel nanomaterials containing RSV-F gene were injected intramuscularly into BALB/c mice, resulting in high copy number of the transgene. In this study, we report, for the first time, the application of the PCNSs as a nanovehicle for gene delivery in vitro and in vivo. PMID:23610520

  18. Exposure to volatile methacrylates in dental personnel.

    PubMed

    Hagberg, Stig; Ljungkvist, Göran; Andreasson, Harriet; Karlsson, Stig; Barregård, Lars

    2005-06-01

    Dental personnel are exposed to acrylates due to the acrylic resin-based composites and bonding agents used in fillings. It is well known that these compounds can cause contact allergy in dental personnel. However, in the 1990s, reports emerged on asthma also caused by methacrylates. The main volatile acrylates in dentistry are 2-hydroxyethyl methacrylate and methyl methacrylate. The aim of this study was to quantify the exposure to these acrylates in Swedish dental personnel. We studied the exposure to 2-hydroxyethyl methacrylate and methyl methacrylate in five randomly selected public dental clinics and at the Faculty of Odontology at Göteborg University. In total, 21 whole-day and 46 task-specific short-term (1-18 min) measurements were performed. The median 8-hour time-weighted averages were 2.5 microg/m3 (dentists) and 2.9 microg/m3 (dental nurses) for 2-hydroxyethyl methacrylate, and 0.8 microg/m3 (dentists) and 0.3 microg/m3 (dental nurses) for methyl methacrylate. The maximum short-term exposure levels were 79 microg/m3 for 2-hydroxyethyl methacrylate and 15 microg/m3 for methyl methacrylate, similar in dentists and dental nurses. The observed levels are much lower than in complete denture fabrication. We found only one previous study in dentistry and it showed similar results (though it reported short-term measurements only). Irritant effects would not be expected in healthy people at these levels. Nevertheless, occupational respiratory diseases due to methacrylates may occur in dental personnel, and improvements in the handling of these chemicals in dentistry are warranted. This includes better vials for the bonding agents and avoiding evaporation from discarded materials.

  19. Synthesis of hydroxyethyl-methacrylate-(L)-histidine methyl ester cryogels. Application on the separation of bovine immunoglobulin G.

    PubMed

    Elkak, Assem; Hamade, Amar; Bereli, Nilay; Armutcu, Canan; Denizli, Adil

    2017-02-21

    In this study cryogels based 2-hydroxyethyl methacrylate (HEMA) functionalized with N-methacryloyl-L-histidine methyl ester (MAH) were synthesized and used for the adsorption and separation of bovine IgG. Two series of cryogels functionalized with 5 and 10 mg of MAH as pseudobioaffinity ligand were prepared and characterized by swelling test, FTIR and SEM analysis. The adsorption efficiency of the bovine immunoglobulin into cryogels is discussed with respect to the following chromatographic parameters: pH, flow rate, initial IgG concentration, adsorption time and ionic strength. Our results show good adsorption of bovine immunoglobulin under mild separation conditions at pH 7.4. The maximum binding capacity was determined (32.4 mg/g of cryogel) and demonstrates the efficiency of the used cryogels. This efficacy is clearly seen upon increasing the maximum binding capacity from 23.2 mg (obtained with cryogels with 5 mg MAH) to 32.4 mg/g (for cryogel with 10 mg MAH ligand concentration). The purity of separated fractions was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Together our observations highlights poly (HEMA-MAH) as an efficient adsorbent for bovine immunoglobulins G separation.

  20. Detection of HEMA in self-etching adhesive systems with high performance liquid chromatography

    NASA Astrophysics Data System (ADS)

    Panduric, V.; Tarle, Z.; Hameršak, Z.; Stipetić, I.; Matosevic, D.; Negovetić-Mandić, V.; Prskalo, K.

    2009-04-01

    One of the factors that can decrease hydrolytic stability of self-etching adhesive systems (SEAS) is 2-hydroxymethylmethacrylate (HEMA). Due to hydrolytic instability of acidic methacrylate monomers in SEAS, HEMA can be present even if the manufacturer did not include it in original composition. The aim of the study was to determine the presence of HEMA because of decomposition by hydrolysis of methacrylates during storage, resulting with loss of adhesion strength to hard dental tissues of the tooth crown. Three most commonly used SEAS were tested: AdheSE ONE, G-Bond and iBond under different storage conditions. High performance liquid chromatography analysis was performed on a Nucleosil C 18-100 5 μm (250 × 4.6 mm) column, Knauer K-501 pumps and Wellchrom DAD K-2700 detector at 215 nm. Data were collected and processed by EuroCrom 2000 HPLC software. Calibration curves were made related eluted peak area to known concentrations of HEMA (purchased from Fluka). The elution time for HEMA is 12.25 min at flow rate 1.0 ml/min. Obtained results indicate that no HEMA was present in AdheSE ONE because methacrylates are substituted with methacrylamides that seem to be more stable under acidic aqueous conditions. In all other adhesive systems HEMA was detected.

  1. A thermally responsive injectable hydrogel incorporating methacrylate-polylactide for hydrolytic lability

    PubMed Central

    Ma, Zuwei; Nelson, Devin M.; Hong, Yi; Wagner, William R.

    2011-01-01

    Injectable thermoresponsive hydrogels are of interest for a variety of biomedical applications, including regional tissue mechanical support as well as drug and cell delivery. Within this class of materials there is a need to provide options for gels with stronger mechanical properties as well as variable degradation profiles. To address this need, the hydrolytically labile monomer, methacrylate-polylactide (MAPLA), with an average 2.8 lactic acid units, was synthesized and copolymerized with N-isopropylacrylamide (NIPAAm) and 2-hydroxyethyl methacrylate (HEMA) to obtain bioabsorbable thermally responsive hydrogels. Poly(NIPAAm-co-HEMA-co-MAPLA) with three monomer feed ratios (84/10/6, 82/10/8 and 80/10/10) was synthesized and characterized with NMR, FTIR and GPC. The copolymers were soluble in saline at reduced temperature (<10°C), forming clear solutions that increased in viscosity with the MAPLA feed ratio. The copolymers underwent sol-gel transition at lower critical solution temperatures of 12.4, 14.0 and 16.2°C respectively and solidified immediately upon being placed in a 37°C water bath. The warmed hydrogels gradually excluded water to reach final water contents of ~45%. The hydrogels as formed were mechanically strong, with tensile strengths as high as 100 kPa and shear moduli of 60 kPa. All three hydrogels were completely degraded (solubilized) in PBS over a 6–8 month period at 37°C, with a higher MAPLA feed ratio resulting in a faster degradation period. Culture of primary vascular smooth muscle cells with degradation solutions demonstrated a lack of cytotoxicity. The synthesized hydrogels provide new options for biomaterial injection therapy where increased mechanical strength and relatively slow resorption rates would be attractive. PMID:20575552

  2. Covalent bonding of PMMA, PBMA, and poly(HEMA)to hydroxyapatite particles.

    PubMed

    Liu, Q; de Wijn, J R; van Blitterswijk, C A

    1998-05-01

    In our earlier study, we showed that the surface hydroxyl groups of hydroxyapatite have the ability to react with organic isocyanate groups. In this study, the feasibility of grafting poly(methyl methacrylate) (PMMA), poly(n-butyl methacrylate) (PBMA), and Poly(hydroxyethyl methacrylate) [poly(HEMA)] by using the reaction of isocyanate groups with the hydroxyl groups on the surface of HA was investigated. Double bonds were introduced to the surface of HA via the coupling reaction of isocyanateoethyl methacrylate (ICEM) with HA, or through hexamethylene diisocyanate (HMDI) with hydroxyethyl methacrylate (HEMA) and HA, followed by radical polymerization in MMA, BMA, or HEMA. Infrared spectra indicated the existence of polymers on the surfaces of HA. Thermogravimetric analysis also confirmed the presence of grafted polymers on the surface of HA powder particles (20-26 wt%). The polymers gave typical PMMA, PBMA, or poly(HEMA) infrared spectra, with the exception of amide bands, a result of the coupling reaction of ICEM or HMDI with hydroxy groups of HA or HEMA. Therefore it is concluded that the polymers were chemically bonded to the surface of HA through the isocyanate groups of ICEM or HMDI.

  3. Diblock copolymers containing compositionally-uniform poly(HEMA-co-DMAEMA)

    NASA Astrophysics Data System (ADS)

    Guice, Kyle; Teoh, Raymond; Loo, Yueh-Lin

    2007-03-01

    Hydroxyethyl methacrylate (HEMA) and dimethylaminoethyl methacrylate (DMAEMA) have been investigated as precursors for pH-responsive hydrogels. DMAEMA contains tertiary amine functionality that is reversibly protonated below its pKa. The swelling characteristics of poly(HEMA-co-DMAEMA) hydrogels are dependent on the distribution of DMAEMA, which in turn depends on the monomer composition and the monomer reactivity ratios. We find that the reactivity ratios are highly solvent dependent. Gradient copolymers are favored in most solvents at all monomer compositions. In dimethylsulfoxide, however, the reactivity ratios are near unity; compositionally-uniform poly(HEMA-co-DMAEMA) copolymers can therefore be synthesized at any composition. We have synthesized diblock copolymers containing poly(HEMA-co-DMAEMA) by a combination of atom transfer radical polymerization and click chemistry. The resulting diblock copolymers have controlled molecular weights, molecular weight distributions, and comonomer distributions, and they form well-defined periodic nanoscale structures consistent with their molecular characteristics.

  4. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  5. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  6. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  7. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  8. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  9. Dextrin/poly (HEMA): pH responsive porous hydrogel for controlled release of ciprofloxacin.

    PubMed

    Das, Dipankar; Pal, Sagar

    2015-01-01

    Herein, we report an oral route administration for ciprofloxacin hydrochloride delivery using dextrin and poly (2-hydroxyethyl methylacrylate) based crosslinked hydrogel (c-Dxt/pHEMA). Various characteristics such as FTIR spectra, XRD analyses, UV-VIS-NIR spectra, FESEM and E-SEM analyses, rheological characteristics, gel kinetics, deswelling characteristics as well as biodegradation study of the hydrogel have been carried out. FTIR, XRD along with solid state UV-VIS-NIR analyses explain the good compatibility between the drug and the hydrogel matrix. The in vitro release study demonstrates that c-Dxt/pHEMA releases ciprofloxacin in a sustained way (33.75% of drug has been released in 18h) and is expected to be a promising matrix for ciprofloxacin carrier. The release kinetics and mechanism suggest that drug release follows first order kinetics and non-Fickian diffusion mechanism. Finally, the hydrogel shows excellent physical stability as carrier for ciprofloxacin up to 3 months.

  10. Anti-fouling poly(2-hydoxyethyl methacrylate) surface coatings with specific bacteria recognition capabilities

    NASA Astrophysics Data System (ADS)

    Mrabet, Bechir; Nguyen, Minh Ngoc; Majbri, Aymen; Mahouche, Samia; Turmine, Mireille; Bakhrouf, Amina; Chehimi, Mohamed M.

    2009-08-01

    Poly(2-hydroxyethyl methacrylate), PHEMA, brushes were prepared by surface-initiated atom transfer radical polymerization (SI-ATRP) on silanized glass slides bearing grafted initiators. High resolution X-ray photoelectron spectroscopy (XPS) highlighted the surface chemical changes of the glass slides upon silanization and surface-confined ATRP of HEMA. Particularly, the initiator sites from the silane were detected by their bromine Br3d core electron peak whilst the O/C atomic ratios and the high resolution C1s region of the glass-PHEMA hybrids are comparable to those of pure PHEMA, thus confirming that the PHEMA chains have indeed attached to the surface. The glass-PHEMA hybrids were found to behave as anti-fouling ultrathin coatings as they resisted non-specific Salmonella typhimurium bacterial adhesion. This behaviour is driven by the hydrophilic properties of the glass-PHEMA hybrids which were assessed by contact angle measurements. In contrast, after activation of PHEMA brushes by S.typhimurium antibodies through the trichlorotriazine coupling procedure, the bacteria specifically and strongly attached to the PHEMA-coated glass slides as judged from optical microscope observation.

  11. Blood compatibility of AAc, HEMA, and PEGMA-grafted cellulose film

    NASA Astrophysics Data System (ADS)

    Nho, Young Chang; Kwon, Oh Hyun

    2003-03-01

    To improve surface blood compatibility on cellulose film for hemodialysis, acrylic acid, 2-hydroxyethyl methacrylate and three kinds of polyethylene glycol methacrylates were grafted onto the cellulose film surface by radiation grafting technique. Heparin was introduced onto the grafted cellulose film surfaces. The grafting and heparinization were confirmed by Fourier transform infrared spectroscopy in the attenuated total reflectance mode and electron spectroscopy for chemical analysis. The blood compatibility of the modified cellulose film was examined by the determination of platelet adhesion and thrombus formation.

  12. Simultaneous measurement of N-Acetyl-S-(2-cyanoethyl)-cysteine and N-acetyl-S-(2-hydroxyethyl)-cysteine in human urine by liquid chromatography-tandem mass spectrometry.

    PubMed

    Xiaotao, Zhang; Hongwei, Hou; Wei, Xiong; Qingyuan, Hu

    2014-08-01

    Acrylonitrile, possibly carcinogenic to humans, is mainly present in tobacco smoke and undergoes metabolism to form N-acetyl-S-(2-cyanoethyl)-cysteine (CEMA) and N-acetyl-S-(2-hydroxyethyl)-cysteine (HEMA). A method based on the direct dilution to simultaneously identify and quantify CEMA and HEMA in human urine by rapid resolution liquid chromatography-electrospray ionization tandem mass spectrometry (RRLC-MS-MS) was validated for assessing smoking-related acrylonitrile exposure. The recovery rates of the whole analytical procedure were 98.2-106.0% and 97.1-112.7% for HEMA and CEMA, respectively. The linear range of standard solutions was 0.5-100.0 ng/mL for CEMA and was 0.2-40.0 ng/mL for HEMA. RRLC using a small particle size column was combined with a tandem mass spectrometry system, which lowered the detection limit of analytes, reduced the ion suppression of mass and shortened the analysis time. The proposed method was successfully applied for the analysis of 126 urine samples from smokers and nonsmokers.

  13. Preparation and characterization of poly(glycidyl methacrylate) grafted from magnesium hydroxide particles via SI-ATRP

    NASA Astrophysics Data System (ADS)

    Liu, Jianhui; Feng, Na; Chang, Suqin; Kang, Hongliang

    2012-06-01

    In order to improve the compatibility of magnesium hydroxide particles [Mg(OH)2] and polymer matrix, poly(glycidyl methacrylate) (PGMA) grafted from magnesium hydroxide particles were synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP). In this work, two approaches for the immobilization of ATRP initiator on the magnesium hydroxide particles surface were compared and selected. The density of initiator was significantly increased by the method of introducing more hydroxyl groups via ATRP of 2-hydroxyethyl methacrylate (HEMA) on the surface. The percentage of bromine atom for the initiator-functionalized magnesium hydroxide particles [Mg(OH)2-g-PHEMA-Br] reached to 1.75%, compared to 0.48% for Mg(OH)2-Br determined by XPS analysis. The surface-initiated ATRP of glycidyl methacrylate (GMA) can be conducted in a controlled manner, as revealed by the linear kinetic plot, linear increase of number average molecular weight (Mn) with monomer conversions, and the relatively narrow molecular weight distributions (Mw/Mn ˜ 1.4) of PGMA chains. The percentage of grafting PG (%) and the thickness of the grafted polymer layer increased with the increasing of polymerization time and reached to 116.6% and 197.6 nm after 300 min respectively. As for the polymerization with different initial monomer concentration, the number average molecular weights (Mn) and weight average molecular weights (Mw) of PGMA increased with the increasing of initial monomer concentration. TGA indicated that the initial decomposition temperature of Mg(OH)2-g-PHEMA-PGMA composite particles (253 °C) was much lower than that of unmodified magnesium hydroxide particles (337 °C).

  14. Plasma modification of HEMA and EOEMA surface properties

    NASA Astrophysics Data System (ADS)

    Svorcik, V.; Kolarova, K.; Dvorankova, B.; Michalek, J.; Krumbholcova, E.; Hnatowicz, V.

    2006-01-01

    Process of plasma etching of poly(2-hydroxyethylmethacrylate) (HEMA) and poly(2-ethyloxyethyl methacrylate) (EOEMA) in Ar atmosphere at room temperature was studied. Ablation of the samples exposed to the plasma was determined by gravimetry, surface wettability by goniometry, chemical structure by FTIR spectroscopy and surface morphology by Scanning Electron (SEM) microscopy. Adhesion and proliferation of 3T3 mouse fibroblasts was studied in vitro in order to determine biological activity of plasma-modified HEMA and EOEMA substrates. It was demonstrated that the plasma etching leads to oxidation of HEMA and to an increase of its wettability. More estheric structures are produced in EOEMA. For both polymers, a surface layer similar to 2 mu m thick is ablated after plasma etching for 400 s. The etching changes the sample surface morphology and its biological activity. The surface becomes smoother after etching. The results obtained after 3T3 cells cultivation show that the plasma etching decreases cell adhesion and increases cell proliferation in comparison with pristine polymers.

  15. Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents

    NASA Astrophysics Data System (ADS)

    Mellman, James Kenneth

    Ureteral stents develop calcium-bearing deposits, called encrustation, that diminish their biocompatibility due to complications, such as chronic abrasion to the lumen of the ureter wall and subsequent infection. A reduction of encrustation, namely calcium oxalate, will improve the lifetime, health care costs, and infection resistance of such devices. The purpose of this research project is to study oxalate-degrading enzymes entrapped into a coating material that will control the interface to the urinary environment for ureteral stents. The coating material was a lightly crosslinked poly(2-hydroxyethyl methacrylate) (p(HEMA)) matrix in which the active enzymes were entrapped within the bulk material's free volume. The swelling of p(HEMA) films was comparable in ddH2O and urine. This hydrophilic matrix allows oxalate anions to diffuse into the bulk so that enzyme activity against oxalate can lower its local concentration, and thereby reduce the supersaturation of calcium oxalate. Oxalate oxidase (OxO) and oxalate decarboxylase (OxDc) were the oxalate-degrading enzymes examined herein. Michaelis Menten kinetic models were applied to free and immobilized enzyme activity. A substrate inhibition model was applied to OxO. The free form of OxO had a Vmax of 1.8 +/- 0.1 muM/min-mug, a km of 1.8 +/- 0.1 mM, and a ks of 35.4 +/- 3.7 mM while the immobilized form had a Vmax of 1.2 +/- 0.2 muM/min-mug, a km of 4.1 +/- 0.6 mM, and a ks of 660 +/- 140 mM. The free form of OxDc had a Vmax of 23.5 +/- 1.4 muM/min-mug and a km of 0.5 +/- 0.1 mM while the immobilized form had a Vmax of 5.0 +/- 1.9 muM/min-mug and km of 23.2 +/- 9.1 mM. The enzyme activity was measured to indicate viable application conditions for the coating, such as storing the films in urine over time. The maximum activity was shown at pH 4.2 to 4.5 and activity drops to be negligible by pH 7.0. Storing the enzyme at pH 6.1 exhibited a larger retained activity than storing at pH 4.2, yet storing in urine showed

  16. Efficient Synthesis of Poly(hydroxyethyl Methacrylate)-b-Poly(dimethylaminoethyl Methacrylate) Block Copolymer by Atom Transfer Radical Polymerization.

    NASA Astrophysics Data System (ADS)

    Tang, Wei; Loo, Yueh-Lin

    2009-03-01

    Polymers containing hydroxyethyl methacrylate (HEMA) and dimethylaminoethyl methacrylate (DMAEMA) have found wide applications in areas such as bioseparation, tissue engineering and controlled drug delivery. The controlled synthesis of block copolymers of PDMAEMA-b-PHEMA from PDMAEMA macroinitiator by atom transfer radical polymerization (ATRP), however, has not been successful due to the loss of chain end functionality during polymerization. We report an ATRP system that affords efficient chain extension from PDMAEMA to HEMA using Cu(0)/1,1,4,7,10,10-hexamethyltriethylenetetramine as the catalyst, 2-chloropropionitrile as the initiator in methanol at room temperature. A clear peak shift in the gel permeation chromatography trace towards shorter elution times indicates chain growth on HEMA addition. The chain end functionalities of PDMAEMA are thus retained and can be used to efficiently initiate chain extension reaction of HEMA. This new synthetic route opens new possibilities for the synthesis of pH- and temperature-responsive systems containing DMAEMA.

  17. A microfluidic approach to fabricate monodisperse hollow or porous poly(HEMA-MMA) microspheres using single emulsions as templates.

    PubMed

    Zhang, Hao; Ju, Xiao-Jie; Xie, Rui; Cheng, Chang-Jing; Ren, Ping-Wei; Chu, Liang-Yin

    2009-08-01

    We have successfully developed a novel and simple method to controllably prepare monodisperse poly(hydroxyethyl methacrylate-methyl methacrylate) (poly(HEMA-MMA)) microspheres with two distinct structures using single emulsions as templates. By employing a microfluidic emulsification approach to fabricate monomer-contained oil-in-water (O/W) emulsions as templates, and introducing proper initiators and different types of porogens, poly(HEMA-MMA) microspheres with hollow or porous structure are prepared in a controllable way. The shell thickness of hollow microspheres or the porosity of porous microspheres is controllably achieved by simply adjusting the porogen concentration. The prepared poly(HEMA-MMA) microspheres with controllable hollow or porous structures are favored for various potential applications. Furthermore, by using the simple preparation methodology proposed in this study, fabrication of monodisperse porous microspheres or hollow microcapsules with other materials can also be easily achieved.

  18. Synthesis of Cr(VI)-imprinted poly(4-vinyl pyridine-co-hydroxyethyl methacrylate) particles: its adsorption propensity to Cr(VI).

    PubMed

    Bayramoglu, Gulay; Arica, M Yakup

    2011-03-15

    The aim of this study is to prepare ion-imprinted polymers, which can be used for the selective removal of Cr(VI) anions from aqueous media. 4-Vinyl pyridine (4-VP) was used as functional monomer. The Cr(VI)-imprinted poly(4-vinyl pyridine-co-2-hydroxyethyl methacrylate), poly(VP-HEMA), particles were prepared by bulk polymerization. The Cr(VI)-imprinted polymer particles were grained from the bulk polymer, and the template ions (i.e., Cr(VI)) were removed using thiourea (0.5%, v/v) in 0.5M HCl. The Cr(VI)-imprinted polymer contained 21.4 μmol 4-VP/g polymers. The specific surface area of the IIP2 particles was found to be 34.5m(2)/g (size range of 75-150 μm), and the swelling ratio was about to 108%. The effect of initial concentration of Cr(VI) anions, the adsorption rate and the pH of the medium on adsorption capacity of Cr(VI)-imprinting polymer were studied. The maximum experimental adsorption capacity was 3.31 mmol Cr(VI)/g polymer. Under competitive condition, the adsorption capacity of Cr(VI)-imprinted particles for Cr(VI) is 13.8 and 11.7 folds greater than that of the Cr(III) and Ni(II) ions, respectively. The first- and second order kinetics models were estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. The Langmuir adsorption isotherm model was well described the Cr(VI)-imprinted system and the maximum adsorption capacity (Q(max)) was found to be 3.42 mmol/g. Moreover, the reusability of the poly(VP-HEMA) particles was tested for several times and no significant loss in adsorption capacity was observed.

  19. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  20. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  1. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  2. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  3. 40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction...

  4. 40 CFR 721.3152 - Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates (salts). 721.3152 Section 721... Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates... ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

  5. 40 CFR 721.3152 - Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates (salts). 721.3152 Section 721... Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates... ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

  6. 40 CFR 721.3152 - Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates (salts). 721.3152 Section 721... Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates... ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

  7. 40 CFR 721.3152 - Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates (salts). 721.3152 Section 721... Ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl sulfates... ethanaminium, N-ethyl-2-hydroxy-N,N-bis(2-hydroxyethyl)-, diester with C12-18 fatty acids, ethyl...

  8. HEMA but not TEGDMA induces autophagy in human gingival fibroblasts

    PubMed Central

    Teti, Gabriella; Orsini, Giovanna; Salvatore, Viviana; Focaroli, Stefano; Mazzotti, Maria C.; Ruggeri, Alessandra; Mattioli-Belmonte, Monica; Falconi, Mirella

    2015-01-01

    Polymerized resin-based materials are successfully used in restorative dentistry. Despite their growing popularity, one drawback is the release of monomers from the polymerized matrix due to an incomplete polymerization or degradation processes. Released monomers are responsible for several adverse effects in the surrounding biological tissues, inducing high levels of oxidative stress. Reactive oxygen species are important signaling molecules that regulate many signal-trasduction pathways and play critical roles in cell survival, death, and immune defenses. Reactive oxygen species were recently shown to activate autophagy as a mechanism of cell survival and cell death. Although the toxicity induced by dental resin monomers is widely studied, the cellular mechanisms underlying these phenomena are still unknown. The aim of the study was to investigate the behavior of human gingival cells exposed to 2-hydroxy-ethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) to better elucidate the mechanisms of cell survival and cell death induced by resin monomers. Primary culture of human gingival cells were exposed to 3 mmol/L of HEMA or 3 mmol/L of TEGDMA for 24, 48, and 72 h. Morphological investigations were performed by transmission electron microscopy to analyze the ultrastructure of cells exposed to the monomers. The expression of protein markers for apoptosis (caspase – 3 and PARP) and autophagy (beclin – 1 and LC3B I/II) were analyzed by western blot to investigate the influence of dental resin monomers on mechanisms underlying cell death. Results showed that HEMA treatment clearly induced autophagy followed by apoptosis while the lack of any sign of autophagy activation is observed in HGFs exposed to TEGDMA. These data indicate that cells respond to monomer-induced stress by the differential induction of adaptive mechanisms to maintain cellular homeostasis. PMID:26483703

  9. Functionalized chitosan/NIPAM (HEMA) hybrid polymer networks as inserts for ocular drug delivery: synthesis, in vitro assessment, and in vivo evaluation.

    PubMed

    Verestiuc, Liliana; Nastasescu, Oana; Barbu, Eugen; Sarvaiya, Indrajeetsinh; Green, Keith L; Tsibouklis, John

    2006-06-15

    A series of hybrid polymeric hydrogels, prepared by the reaction of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate monomers, were synthesized, pressed into minitablets, and investigated for their ability to act as controlled release vehicles for ophthalmic drug delivery. For comparison, interpolymeric complex analogues synthesized using the same monomers and pure, unfunctionalized chitosan were examined by means of an identical characterization protocol. The effects of network structure and composition upon the swelling properties, adhesion behavior, and drug release characteristics were investigated. Comparative in vitro studies employing chloramphenicol, atropine, norfloxacin, or pilocarpine informed the selection of drug-specific carrier compositions for the controlled delivery of these compounds. In addition, in vivo (rabbit model) experiments involving the delivery of pilocarpine indicated that chitosan-based hybrid polymer networks containing 2-hydroxyethyl methacrylate are useful carriers for the delivery of this therapeutic agent.

  10. Synthesis and evaluation of 2'-hydroxyethyl trans-apovincaminate derivatives as antioxidant and cognitive enhancer agents.

    PubMed

    Nemes, András; Czibula, László; Szántay, Csaba; Gere, Anikó; Kiss, Béla; Laszy, Judit; Gyertyán, István; Szombathelyi, Zsolt; Szántay, Csaba

    2008-02-14

    A series of trans-2'-hydroxyethyl and 2'-acyloxyethyl apovincaminates 4b- f and 7b- f has been synthesized and evaluated for their antioxidant and antiamnesic effects. The new esters were prepared from 4a and 7a ethyl esters or from the corresponding carboxylic acid sodium salt. For starting materials 11a, b, a new stereoselective trans-reduction was elaborated. From the combined results of the data obtained from in vitro and in vivo tests and examination of the metabolism, (3 R,16 S)-2'-hydroxyethyl apovincaminate ( 7b, RGH-10885) was identified as the most promising compound, owing to its potent neuroprotective and antiamnesic activities. The in vivo effectiveness of selected compounds on the cognitive functions was studied in a one-trial passive avoidance task and a water-labyrinth test.

  11. Synthesis and characterization of fluorinated methacrylates-based copolymers containing cross-linkable pendant groups for optical waveguides

    NASA Astrophysics Data System (ADS)

    Kim, Ho June; Kim, Kwangsok; Chin, In-Joo

    2006-02-01

    Methacrylate based copolymers containing thermal and UV cross-linkable groups were prepared, ad their optical properties were investigated. Copolymerization of octafluoropentyl methacrylate (OFPMA) with hydroxyethyl methacrylate (HEMA) was followed by reacting HEMA and methacrylic anhydride (MAAN), yielding a fluorinated copolymer with cross-linkable pendant group. The refractive indices of the copolymers before cross-linking ranged from 1.4329 to 1.4646, and those of the cross-linked copolymers varied from 1.4500 to 1.4822, depending on the fluorine content.

  12. Chlorhexidine-releasing methacrylate dental composite materials.

    PubMed

    Leung, Danny; Spratt, David A; Pratten, Jonathan; Gulabivala, Kishor; Mordan, Nicola J; Young, Anne M

    2005-12-01

    Light curable antibacterial, dental composite restoration materials, consisting of 80 wt% of a strontium fluoroaluminosilicate glass dispersed in methacrylate monomers have been produced. The monomers contained 40-100 wt% of a 10 wt% chlorhexidine diacetate (CHXA) in hydroxyethylmethacrylate (HEMA) solution and 60-0 wt% of a 50/50 mix of urethane dimethacrylate (UDMA) and triethyleneglycol dimethacrylate (TEGDMA). On raising HEMA content, light cure polymerisation rates decreased. Conversely, water sorption induced swelling and rates of diffusion controlled CHXA release from the set materials increased. Experimental composites with 50 and 90 wt% of the CHXA in HEMA solution in the monomer were shown, within a constant depth film fermentor (CDFF), to have slower rates of biofilm growth on their surfaces between 1 and 7 days than the commercial dental composite Z250 or fluoride-releasing dental cements, Fuji II LC and Fuji IX. When an excavated bovine dentine cylinder re-filled with Z250 was placed for 10 weeks in the CDFF, both bacteria and polymers from the artificial saliva penetrated between the material and dentine. With the 50 wt% experimental HEMA/CHXA formulation, this bacterial microleakage was substantially reduced. Polymer leakage, however, still occurred. Both polymer and bacterial microleakage were prevented with a 90 wt% HEMA/CHXA restoration in the bovine dentine due to swelling compensation for polymerisation shrinkage in combination with antibacterial release.

  13. Characterisation of gamma irradiated chitosan/pHEMA membranes for biomedical purposes

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Leal, J. P.; Gil, M. H.

    2005-07-01

    As a polysaccharide of natural origin, chitosan has the inherent properties of being biocompatible, biodegradable, and non-toxic. These properties make chitosan an ideal candidate for based backbone in copolymeric matrices for use in biomedical applications. Poly(hydroxyethyl methacrylate) is a synthetic hydrogel which possesses a high mechanical strength. The conjunction of these two components results in a new matrix that combines the useful properties of the synthetic pHEMA and natural chitosan. In this work chitosan/pHEMA membranes were obtained and γ-irradiated under nitrogen atmosphere. The effect of various synthesis conditions on the chemical, physical and biological properties was evaluated. The chitosan/pHEMA membranes were characterised using FTIR spectroscopy, scanning electron microscopy and thermal analysis techniques. Its hydration capacity and its antimicrobial properties were also determined. The obtained results showed that the hydration capacity decreases in the irradiated membranes. It was also found that chitosan/pHEMA membranes present good barrier properties against microbes.

  14. Drug release assays from new chitosan/pHEMA membranes obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Casimiro, M. H.; Gil, M. H.; Leal, J. P.

    2007-12-01

    With the purpose of obtaining a biocompatible and microbiologically safe matrix that simultaneously could be used as wound dressing material and as a controlled drug release system, membranes with different thickness and different contents in chitosan and hydroxyethyl methacrylate (HEMA) have been prepared by γ irradiation from a 60Co source. Antibiotic release experiments were performed before or after irradiation over amoxicillin loaded chitosan/pHEMA membranes in physiological saline solution, and monitored by UV-Vis spectrometry. Results point out a fast amoxicillin release with similar release profile in all studied membranes. The amount of released drug was shown to be dependent on membranes network crosslinking due composition, radiation and membrane thickness.

  15. Tunable and Reversible Swelling of a p(tBA)-b-p(HEMA-co-DMAEMA) Block Copolymer

    NASA Astrophysics Data System (ADS)

    Guice, Kyle; Loo, Yueh-Lin

    2006-03-01

    Hydroxyethyl methacrylate (HEMA) and dimethylaminoethyl methacrylate (DMAEMA) have been investigated as precursor materials for pH-responsive hydrogels. DMAEMA in these hydrogel systems allows for pH-tunability, as it is reversibly protonated below its pKa (7.5). In this work, we present the design of a nano-structured hydrogel diblock copolymer whose major block consists of a statistical copolymer of p(HEMA-co-DMAEMA) (30.5 kg/mol) polymerized at the azeotropic composition (71 mol% HEMA), with a poly(tert-butyl acrylate), p(tBA), (12.1 kg/mol) minor block. The resulting diblock copolymer is narrow in molecular weight distribution (PDI = 1.24) and spontaneously self-assembles to form hexagonally-packed p(tBA) cylinders (R = 9.5 nm) within a p(HEMA-co-DMAEMA) matrix in the solid state. When swollen in an aqueous medium, hydrophobic p(tBA) cylinders serve as physical cross-links. We monitor the extents of swelling by quantifying changes in the characteristic (10) spacing of the hexagonal lattice by SAXS. Swelling is tunable and reversible with changes in pH; we observe 35% and 21% swelling relative to the dry state at pH 5 and 8.5, respectively.

  16. A robust new strategy for high-molecular-weight proteome research: a 2-hydroxyethyl agarose/polyacrylamide gel enhanced separation and ZnO-PMMA nanobeads assisted identification.

    PubMed

    Shen, Wenwen; Shen, Chengpin; Xiong, Huanming; Lu, Haojie; Yang, Pengyuan

    2010-09-15

    A new mass spectrometry based analysis strategy has been established here for high-molecular-weight (HMW) proteome research. First, a 2-hydroxyethyl agarose/polyacrylamide (HEAG/PAM) electrophoresis gel was designed for the first time to realize an easy-handling separation method with high spatial resolution for HMW proteins, good reproducibility and mass spectrometry-compatible silver staining. Second, ZnO-polymethyl methacrylate (ZnO-PMMA) nanobeads were applied here for enriching and desalting the peptides from the HMW proteins. Third, the peptides were analyzed by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) with the presence of the ZnO-PMMA nanobeads, and their MS signals were enhanced markedly. The success rate of identification for HMW proteins was significantly increased due to high enriching efficiency and salt tolerance capability as well as signal enhancing capability of the ZnO-PMMA nanobeads. We believe that this analysis strategy will inspire and accelerate the HMW proteome studies.

  17. Bis[2-(2-hydroxyethyl)pyridinium] mu-decavanadato-bis[pentaaquamanganate(II)] tetrahydrate.

    PubMed

    Klistincová, Lenka; Rakovský, Erik; Schwendt, Peter

    2009-02-01

    The structure of the title compound, (C(7)H(10)NO)(2)[Mn(2)V(10)O(28)(H(2)O)(10)].4H(2)O or (C(5)H(4)NHCH(2)CH(2)OH)(2)[{Mn(H(2)O)(5)}(2)V(10)O(28)].4H(2)O, at 293 (2) K has triclinic (P\\overline{1}) symmetry. The asymmetric unit consists of one half of a decavanadate anion of C(i) symmetry, one [Mn(H(2)O)(5)](2+) group, one 2-(2-hydroxyethyl)pyridinium cation and two solvent water molecules. The decavanadate ion bridges between two [Mn(H(2)O)(5)](2+) groups, thus forming a dodecanuclear complex unit. Complex units are connected via a hydrogen-bonding network, forming supramolecular layers lying in the (001) plane. Cations and solvent water molecules are located between these layers.

  18. Rotational isomers, NBO and spectral analyses of N-(2-hydroxyethyl) phthalimide based on quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Lakshmi, A.; Balachandran, V.

    2013-02-01

    FT-IR and FT-Raman spectra of N-(2-hydroxyethyl)phthalimide (NHEP) have been recorded and analyzed. The stable isomer of NHEP is determined. The optimization geometry, intermolecular hydrogen bonding, and harmonic vibrational wavenumber of NHEP have been investigated with the help of B3LYP scaled quantum mechanical (SQM) method. The infrared and Raman spectra were predicted theoretically from the calculated intensities. Natural bond orbital (NBO) analysis indicates the presence of Cdbnd O⋯H in the molecule. The calculated HOMO and LUMO are important in determining such properties as molecular reactivity. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with electrostatic potential (ESP).

  19. 40 CFR 721.10115 - 1-Hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 1-Hexadecanaminium, N,N-dibutyl-N-(2... New Uses for Specific Chemical Substances § 721.10115 1-Hexadecanaminium, N,N-dibutyl-N-(2... chemical substance identified as 1-hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1) (PMN...

  20. 40 CFR 721.10115 - 1-Hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1-Hexadecanaminium, N,N-dibutyl-N-(2... New Uses for Specific Chemical Substances § 721.10115 1-Hexadecanaminium, N,N-dibutyl-N-(2... chemical substance identified as 1-hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1) (PMN...

  1. 40 CFR 721.10115 - 1-Hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1-Hexadecanaminium, N,N-dibutyl-N-(2... New Uses for Specific Chemical Substances § 721.10115 1-Hexadecanaminium, N,N-dibutyl-N-(2... chemical substance identified as 1-hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1) (PMN...

  2. 40 CFR 721.10115 - 1-Hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 1-Hexadecanaminium, N,N-dibutyl-N-(2... New Uses for Specific Chemical Substances § 721.10115 1-Hexadecanaminium, N,N-dibutyl-N-(2... chemical substance identified as 1-hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1) (PMN...

  3. 40 CFR 721.10115 - 1-Hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 1-Hexadecanaminium, N,N-dibutyl-N-(2... New Uses for Specific Chemical Substances § 721.10115 1-Hexadecanaminium, N,N-dibutyl-N-(2... chemical substance identified as 1-hexadecanaminium, N,N-dibutyl-N-(2-hydroxyethyl)-, bromide (1:1) (PMN...

  4. Photopatterning of a p(HEMA) based, pH-sensitive hydrogel

    SciTech Connect

    Lesho, M.J.; Sheppard, N.F. Jr.

    1993-12-31

    A photopolymerization process was used to prepare patterned films of poly(hydroxyethyl methacrylate -co- dimethylaminoethyl methacrylate) hydrogels with lateral dimensions of a few mm. Lithographic sensitivity, thickness, lateral resolution, and adhesion were characterized. To prepare the films, a prepolymer solution as formulated consisting of the monomers, crosslinker, photoinitiator and poly(HEMA) to increase viscosity. This was spun at various spin speeds onto oxidized silicon wafers treated with a silane adhesion promoter. The wafers were then exposed through a photomask to UV light to effect the polymerization. At a photoinitiator concentration of 2% w/w and an ultraviolet dose greater than 400 mJ/cm{sup 2}, gels were reproducible and ranged in thickness from 3.5 to 22 microns depending on the p(HEMA) concentration and spin speed. Edge effects at the mask boundary limited the lateral resolution to 60 microns. Films remained adherent up to 4 weeks while undergoing daily cycling from pH 5 to 9.

  5. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    TOXICOLOGICAL REVIEW of METHYL METHACRYLATE ( CAS No . 80 - 62 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) January 1998 U.S . Environmental Protection Agency Washington , DC TABLE OF CONTENTS DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . .

  6. Repair of spinal cord injury by implantation of bFGF-incorporated HEMA-MOETACL hydrogel in rats

    NASA Astrophysics Data System (ADS)

    Chen, Bo; He, Jianyu; Yang, Hao; Zhang, Qian; Zhang, Lingling; Zhang, Xian; Xie, En; Liu, Cuicui; Zhang, Rui; Wang, Yi; Huang, Linhong; Hao, Dingjun

    2015-03-01

    There is no effective strategy for the treatment of spinal cord injury (SCI). An appropriate combination of hydrogel materials and neurotrophic factor therapy is currently thought to be a promising approach. In this study, we performed experiments to evaluate the synergic effect of implanting hydroxyl ethyl methacrylate [2-(methacryloyloxy)ethyl] trimethylammonium chloride (HEMA-MOETACL) hydrogel incorporated with basic fibroblast growth factor (bFGF) into the site of surgically induced SCI. Prior to implantation, the combined hydrogel was surrounded by an acellular vascular matrix. Sprague-Dawley rats underwent complete spinal cord transection at the T-9 level, followed by implantation of bFGF/HEMA-MOETACL 5 days after transection surgery. Our results showed that the bFGF/HEMA-MOETACL transplant provided a scaffold for the ingrowth of regenerating tissue eight weeks after implantation. Furthermore, this newly designed implant promoted both nerve tissue regeneration and functional recovery following SCI. These results indicate that HEMA-MOETACL hydrogel is a promising scaffold for intrathecal, localized and sustained delivery of bFGF to the injured spinal cord and provide evidence for the possibility that this approach may have clinical applications in the treatment of SCI.

  7. Antimicrobial Coatings Obtained in an Atmospheric Pressure Dielectric Barrier Glow Discharge

    DTIC Science & Technology

    2002-04-01

    obtained under specific plasma conditions starting from 2- hydroxyethyl methacrylate ( HEMA ) and ethyl diazoacetate (EDA). INTRODUCTION In the initial step of...high surface energies, are 2- hydroxyethyl methacrylate ( HEMA , H2C=C(CI 11)COO 2CH2CH 2OH) and ethyl diazoacetate (EDA, N2CI IC0 2C2 11 𔃿) (Sigma...shows the SEM cross-sections of the coatings resulting from the deposition of HEMA on silicon obtained in a N2 and Ar plasma. After a deposition time

  8. Small Molecule Inhibitors of EGFR Ectodomain for Breast Cancer Therapy

    DTIC Science & Technology

    2009-08-01

    ectodomain inhibitor EL1-FD1 on cell proliferation in human breast cancer cell line MDA-MB-468. 5 mg/ml Poly(2- hydroxyethyl methacrylate ) (PolyHEMA) powder...poly- HEMA assay. The compound effectively inhibited tumor growth in mice with MDA-MB-468 xenografts and had a moderate effect in MDA-MB-231 xenografts

  9. Small Molecule Inhibitors of EGFR Ectodomain for Breast Cancer Therapy

    DTIC Science & Technology

    2011-08-01

    proliferation in human breast cancer cell line MDA-MB-468. 5 mg/ml Poly(2- hydroxyethyl methacrylate ) (PolyHEMA) powder (Sigma) in 95% ethanol was dissolved at...compound against MDA-MB-468 cells has been demonstrated in a poly- HEMA assay. The compound effectively inhibited tumor growth in mice with MDA-MB-468

  10. Proton Conducting Polymer Membrane Comprised of 2-Acrylamido-2-Methylpropanesulfonic Acid

    DTIC Science & Technology

    2002-05-01

    copolymer of hydrophilic 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 2- hydroxyethyl methacrylate ( HEMA ). Fumed silicas were also added in an... HEMA had a room temperature proton conductivity of 0.029 S cm-1, which increased to 0.06 S cm-1 at 80 C.

  11. P(TA) macro-, micro-, nanoparticle-embedded super porous p(HEMA) cryogels as wound dressing material.

    PubMed

    Sahiner, Nurettin; Sagbas, Selin; Sahiner, Mehtap; Silan, Coskun

    2017-01-01

    Super porous poly(2-hydroxy ethyl methacrylate) (p(HEMA)) cryogel was successfully synthesized by using polyethylene glycol diacrylate (p(EGDA)) crosslinker under cryogenic conditions. Poly(Tannic acid) (p(TA)) macro-, micro-, and nanoparticles prepared from a natural polyphenol, tannic acid (TA), were embedded into p(HEMA) cryogel networks to obtain composite p(TA) particle-embedded p(HEMA) cryogel. Different size ranges of spherical p(TA) particles, 2000-500μm, 500-200μm, 200-20μm, and 20-0.5μm size, were included in the cryogel network and illustrated by digital camera, optic microscope, and SEM images of the microgel-cryogel network. The swelling properties and moisture content of p(TA) microgel-embedded p(HEMA) cryogel were investigated at wound healing pH conditions such as pH5.4, 7.4, and 9 at 37.5°C, and the highest swelling capacity was found at pH9 with 972±2% swelling in 30s. Higher amounts of DI water were quickly absorbed by p(HEMA)-based cryogel, and moisture retention within the cryogel structure for a longer time period at room temperature is due to existence of p(TA) particles. Degradation profiles of p(TA) particle-embedded p(HEMA) cryogel were shown to be controlled by different pH conditions, and a linear release profile was found with total cumulative release of 5.8±0.8mg/g TA up to 12days at pH7.4 and 37.5°C. The antioxidant behavior of degraded p(TA) particles from p(HEMA) cryogel were found as 46±1μgmL(-1) gallic acid equivalent and 165±18mMtroloxequivalentg(-1). The p(TA) particle-embedded p(HEMA) cryogel has high hemocompatibility with 0.0158±0.0126% hemolysis ratio, and effective hemostatic properties with 8.1±0.9 blood clotting index.

  12. Synthesis and Characterization of Poly(hydroxyethyl methacrylate) Hydrogels Bearing Reversibly Associating Side Groups

    NASA Astrophysics Data System (ADS)

    Lewis, Christopher; Li, Jiahui; Anthamatten, Mitchell

    2012-02-01

    Poly(hydroxyethyl methacrylate) (poly(HEMA)) is a technologically important hydrogel that can be processed into different shapes and is best known for its role in contact lenses. However, applications of water swollen polyHEMA are limited by its poor mechanical properties. We are studying the influence of reversibly associating side groups on the behavior of poly(HEMA) hydrogels. In non-polar media, it is well known that ureidopyrimidinone (UPy) groups self-associate to form hydrogen bonded dimers (DDAA); however their behavior in water-swollen hydrogels is unclear. A series of poly(HEMA) linear polymers of controlled molecular weight with varying UPy content have been prepared using a reversible addition-fragmentation chain transfer (RAFT) polymerization technique. UPy content significantly reduces water swelling and improves mechanical properties. The degree of hydrogen bonding within water swollen hydrogels is studied, and properties of functional hydrogel polymers and networks are compared to an unswollen hydrophobic analog.

  13. Final report of the safety assessment of methacrylate ester monomers used in nail enhancement products.

    PubMed

    2005-01-01

    Methacrylate ester monomers are used in as artificial nail builders in nail enhancement products. They undergo rapid polymerization to form a hard material on the nail that is then shaped. While Ethyl Methacrylate is the primary monomer used in nail enhancement products, other methacrylate esters are also used. This safety assessment addresses 22 other methacrylate esters reported by industry to be present in small percentages as artificial nail builders in cosmetic products. They function to speed up polymerization and/or form cross-links. Only Tetrahydrofurfuryl Methacrylate was reported to the FDA to be in current use. The polymerization rates of these methacrylate esters are within the same range as Ethyl Methacrylate. While data are not available on all of these methacrylate esters, the available data demonstrated little acute oral, dermal, or i.p. toxicity. In a 28-day inhalation study on rats, Butyl Methacrylate caused upper airway irritation; the NOAEL was 1801 mg/m3. In a 28-day oral toxicity study on rats, t-Butyl Methacrylate had a NOAEL of 20 mg/kg/day. Beagle dogs dosed with 0.2 to 2.0 g/kg/day of C12 to C18 methacrylate monomers for 13 weeks exhibited effects only in the highest dose group: weight loss, emesis, diarrhea, mucoid feces, or salivation were observed. Butyl Methacrylate (0.1 M) and Isobutyl Methacrylate (0.1 M) are mildly irritating to the rabbit eye. HEMA is corrosive when instilled in the rabbit eye, while PEG-4 Dimethacrylate and Trimethylolpropane Trimethacrylate are minimally irritating to the eye. Dermal irritation caused by methacrylates is documented in guinea pigs and rabbits. In guinea pigs, HEMA, Isopropylidenediphenyl Bisglycidyl Methacrylate, Lauryl Methacrylate, and Trimethylolpropane Trimethacrylate are strong sensitizers; Butyl Methacrylate, Cyclohexyl Methacrylate, Hexyl Methacrylate, and Urethane Methacrylate are moderate sensitizers; Hydroxypropyl Methacrylate is a weak sensitizer; and PEG-4 Dimethacrylate and

  14. Biomimetic potential of some methacrylate-based copolymers: a comparative study.

    PubMed

    Zecheru, Teodora; Filmon, Robert; Rusen, Edina; Mărculescu, Bogdan; Zerroukhi, Amar; Cincu, Corneliu; Chappard, Daniel

    2009-11-01

    Preparation of new biocompatible materials for bone recovery has consistently gained interest in the last few decades. Special attention was given to polymers that contain negatively charged groups, such as phosphate, carboxyl, and sulfonic groups toward calcification. This present paper work demonstrates that other functional groups present also potential application in bone pathology. New copolymers of 2-hydroxyethyl methacrylate with diallyldimethylammonium chloride (DADMAC), glycidyl methacrylate (GlyMA), methacrylic acid (MAA), 2-methacryloyloxymethyl acetoacetate (MOEAA), 2-methacryloyloxyethyltriethylammonium chloride (MOETAC), and tetrahydrofurfuryl methacrylate (THFMA) were obtained. The copolymers were characterized by FTIR, swelling potential, and they were submitted to in vitro tests for calcification and cytotoxicity evaluation. GlyMA and MOETAC-containing copolymers show promising results for further in vivo mineralization tests, as a potential alternative to the classical bone grafts, in bone tissue engineering.

  15. Ammonium methacrylate

    Integrated Risk Information System (IRIS)

    Ammonium methacrylate ; CASRN 16325 - 47 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  16. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors.

    PubMed

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32-35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR.

  17. N6-(2-Hydroxyethyl)-Adenosine Exhibits Insecticidal Activity against Plutella xylostella via Adenosine Receptors

    PubMed Central

    Fang, Ming; Chai, Yiqiu; Chen, Guanjv; Wang, Huidong; Huang, Bo

    2016-01-01

    The diamondback moth, Plutella xylostella, is one of the most important pests of cruciferous crops. We have earlier shown that N6-(2-hydroxyethyl)-adenosine (HEA) exhibits insecticidal activity against P. xylostella. In the present study we investigated the possible mechanism of insecticidal action of HEA on P. xylostella. HEA is a derivative of adenosine, therefore, we speculated whether it acts via P. xylostella adenosine receptor (PxAdoR). We used RNAi approach to silence PxAdoR gene and used antagonist of denosine receptor (AdoR) to study the insecticidal effect of HEA. We cloned the whole sequence of PxAdoR gene. A BLAST search using NCBI protein database showed a 61% identity with the Drosophila adenosine receptor (DmAdoR) and a 32–35% identity with human AdoR. Though the amino acids sequence of PxAdoR was different compared to other adenosine receptors, most of the amino acids that are known to be important for adenosine receptor ligand binding and signaling were present. However, only 30% binding sites key residues was similar between PxAdoR and A1R. HEA, at a dose of 1 mg/mL, was found to be lethal to the second-instar larvae of P. xylostella, and a significant reduction of mortality and growth inhibition ratio were obtained when HEA was administered to the larvae along with PxAdoR-dsRNA or antagonist of AdoR (SCH58261) for 36, 48, or 60 h. Especially at 48 h, the rate of growth inhibition of the PxAdoR knockdown group was 3.5-fold less than that of the HEA group, and the corrected mortality of SCH58261 group was reduced almost 2-fold compared with the HEA group. Our findings show that HEA may exert its insecticidal activity against P. xylostella larvae via acting on PxAdoR. PMID:27668428

  18. Cloning of the Rhodobacter capsulatus hemA gene.

    PubMed Central

    Biel, S W; Wright, M S; Biel, A J

    1988-01-01

    Portions of the Rhodobacter capsulatus hemA gene have been cloned from a hemA::Tn5 insertion strain into the lambda bacteriophage derivative EMBL3. A cosmid containing the wild-type R. capsulatus hemA gene was isolated by complementation of the hemA::Tn5 mutant. The cosmid contains a 1.4-kilobase EcoRI fragment that spans the hemA::Tn5 insertion site. The entire hemA gene is contained in this fragment and the adjacent 0.6-kilobase EcoRI fragment. Images PMID:2842318

  19. DFT studies of structural and some spectral parameters of copper(II) complexes with N,N,N‧,N″-tetrakis (2-hydroxyethyl/propyl) ethylenediamine and tris(2-hydroxyethyl)amine

    NASA Astrophysics Data System (ADS)

    Kumar, Rakesh; Obrai, Sangeeta; Mitra, Joyee; Sharma, Aparna

    2013-11-01

    The structures and some spectral parameters of three copper(II) complexes; [Cu(THEEN)(H2O)](PIC)2 (1), [Cu(THPEN)] (PIC)2 C3H8O (2) and [Cu(TEAH3)(PIC)] (PIC)ṡ(H2O) (3), previously synthesized and characterized by X-ray diffraction, are here computationally studied by using density functional theory (DFT) in its hybrid form B3LYP. In these complexes, THEEN is N,N,N‧,N″-tetrakis(2-hydroxyethyl) ethylenediamine and THPEN is N,N,N‧,N″-tetrakis(2-hydroxypropyl) ethylenediamine, tetrapodal ligands and TEAH3 is tris(2-hydroxyethyl)amine, a tripodal ligand. The primary coordination sphere of copper(II) ion in complexes (1), (2) and (3) are optimized, structural parameters are calculated, vibrational bands are assigned and energy gaps of frontier orbital (HOMO-LUMO) have been calculated with B3LYP/6-31G/LANL2DZ level of theory using DMSO as solvent. The calculated geometric and spectral results reproduced the experimental data with well agreement. Theoretical calculated molecular orbitals (HOMO-LUMO) and their energies have been calculated that suggest charge transfer occurs within the complexes.

  20. Novel Approach to Chemically Amplified Resist Materials for Next Generation of Lithography

    NASA Astrophysics Data System (ADS)

    Park, Kyoung-sun; Kim, Dae-yong; Choi, Sang-kuk; Suh, Dong Hack

    2003-06-01

    Our research takes the perspective of how to establish resist structures for nanolithography, we prepared nanoparticles with sizes ranging from 10 to 30 nm by intramolecular self-crosslinking of methylmethacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and tert-butyl methacrylate (t-BMA) terpolymer (MMA:HEMA:t-BMA=50%:20%:30%) in an ultradilute solution. As shown in images of pattern side walls by AFM, the chain entanglement of linear polymers made pattern edges and side walls extremely rough.

  1. Properties of UV-Curable Polyurethane Acrylates: Effect of Reactive Diluent.

    DTIC Science & Technology

    1984-06-20

    polyols (CB) (Vulkollan 2020) were received through the courtesy of Dr. H. Hespe of Bayer. Hydroxyethyl methacrylate ( HEMA ) was acquired from Aldrich...T) H3 N=C=O 0 N=C=O 2,4-toluene diisocyanate (T) CH 3 CH2 =L C-O-CH.f-CH.-OH 0 2- hydroxyethyl methacrylate ( HEMA ) REACTIVE DILUENT STRUCTURES CH 2 CH... HEMA is used instead of HEA). Two families of materials based on isocyanatoethyl methacrylate (IEM) were also investigated. IEM combines the acrylate

  2. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ... AGENCY 40 CFR Part 180 Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether... residues of methacrylic acid-methyl methacrylate- polyethylene glycol monomethyl ether methacrylate graft... permissible level for residues of methacrylic acid-methyl methacrylate-polyethylene glycol monomethyl...

  3. Determination of methyl-, 2-hydroxyethyl- and 2-cyanoethylmercapturic acids as biomarkers of exposure to alkylating agents in cigarette smoke.

    PubMed

    Scherer, Gerhard; Urban, Michael; Hagedorn, Heinz-Werner; Serafin, Richard; Feng, Shixia; Kapur, Sunil; Muhammad, Raheema; Jin, Yan; Sarkar, Mohamadi; Roethig, Hans-Juergen

    2010-10-01

    Alkylating agents occur in the environment and are formed endogenously. Tobacco smoke contains a variety of alkylating agents or precursors including, among others, N-nitrosodimethylamine (NDMA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), acrylonitrile and ethylene oxide. We developed and validated a method for the simultaneous determination of methylmercapturic acid (MMA, biomarker for methylating agents such as NDMA and NNK), 2-hydroxyethylmercapturic acid (HEMA, biomarker for ethylene oxide) and 2-cyanoethylmercapturic acid (CEMA, biomarker for acrylonitrile) in human urine using deuterated internal standards of each compound. The method involves liquid/liquid extraction of the urine sample, solid phase extraction on anion exchange cartridges, derivatization with pentafluorobenzyl bromide (PFBBr), liquid/liquid extraction of the reaction mixture and LC-MS/MS analysis with positive electrospray ionization. The method was linear in the ranges of 5.00-600, 1.00-50.0 and 1.50-900 ng/ml for MMA, HEMA and CEMA, respectively. The method was applied to two clinical studies in adult smokers of conventional cigarettes who either continued smoking conventional cigarettes, were switched to test cigarettes consisting of either an electrically heated cigarette smoking system (EHCSS) or having a highly activated carbon granule filter that were shown to have reduced exposure to specific smoke constituents, or stopped smoking. Urinary excretion of MMA was found to be unaffected by switching to the test cigarettes or stop smoking. Urinary HEMA excretion decreased by 46 to 54% after switching to test cigarettes and by approximately 74% when stopping smoking. Urinary CEMA excretion decreased by 74-77% when switching to test cigarettes and by approximately 90% when stopping smoking. This validated method for urinary alkylmercapturic acids is suitable to distinguish differences in exposure not only between smokers and nonsmokers but also between smoking of conventional and

  4. Cell toxicity of methacrylate monomers-the role of glutathione adduct formation.

    PubMed

    Ansteinsson, V; Kopperud, H B; Morisbak, E; Samuelsen, J T

    2013-12-01

    Polymer-based dental restorative materials are designed to polymerize in situ. However, the conversion of methacrylate monomer to polymer is never complete, and leakage of the monomer occurs. It has been shown that these monomers are toxic in vitro; hence concerns regarding exposure of patients and dental personnel have been raised. Different monomer methacrylates are thought to cause toxicity through similar mechanisms, and the sequestration of cellular glutathione (GSH) may be a key event. In this study we examined the commonly used monomer methacrylates, 2-hydroxyethylmethacrylate (HEMA), triethylenglycol-dimethacrylate (TEGDMA), bisphenol-A-glycidyl-dimethacrylate (BisGMA), glycerol-dimethacrylate (GDMA) and methyl-methacrylate (MMA). The study aimed to establish monomers' ability to complex with GSH, and relate this to cellular toxicity endpoints. Except for BisGMA, all the monomer methacrylates decreased the GSH levels both in cells and in a cell-free system. The spontaneous formation of methacrylate-GSH adducts were observed for all methacrylate monomers except BisGMA. However, we were not able to correlate GSH depletion and toxic response measured as SDH activity and changes in cell growth pattern. Together, the current study indicates mechanisms other than GSH-binding to be involved in the toxicity of methacrylate monomers.

  5. Cylindrospermopsin determination using 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) as the internal standard.

    PubMed

    Kikuchi, Sachiko; Kubo, Takuya; Kaya, Kunimitsu

    2007-01-30

    Cylindrospermopsin (CYN) was determined by liquid chromatography/electrospray ionization-mass spectrometry (LC/ESI-MS) using 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid (HEPES) as the internal standard. In the selected ion monitoring of LC/ESI-MS, m/z 414 for CYN and 237 for HEPES were monitored using the negative mode; the retention times of CYN and HEPES were 12.41 and 14.21 min, respectively. CYN was determined from peak area ratios of m/z 414/237. By the treatment of an anion exchange cartridge using a buffer at pH 10.5, CYN was isolated and condensed. No interfering peak was observed. Linearity of this method was observed at the range of 0.10-31.12 ng. Total coefficients of variation were 5.1 and 2.9% at 104 and 1038 microg CYN L(-1). The quantitative limit at a signal-to-noise (S/N) ratio of 10 was 0.16 ng. CYN concentration in natural waters is low. CYN in waters should be condensed for determination. This method including the treatment for isolation and condensation of CYN is useful for determination of CYN in environmental and/or drinking waters.

  6. Pharmacokinetics and metabolism of N-(2-hydroxyethyl)-2,5-[14C]-pyrrolidine (HEP, Epolamine) in male healthy volunteers.

    PubMed

    Giachetti, C; Assandri, A; Mautone, G; Tajana, E; Palumbo, B; Palumbo, R

    1996-01-01

    N-(2-hydroxyethyl)-pyrrolidine (HEP, Epolamine) is a strong base used to salify organic acids of pharmaceutical interest in order to improve their solubility in water. Diclofenac-HEP (Flector) is the first example of an epolamine salt of a drug. In this study, [14C]-HEP was administered by oral route (300 mg, about 50 microCi/subject) to 3 volunteers with the aim to investigate its plasma profile and to calculate the relevant pharmacokinetic parameters. The experimental data correlated with a two-compartment pharmacokinetic model. Total radioactivity in urine and faeces was also measured. The radioactivity was excreted preferentially by the faecal route (about 65% of the dose administered in the 0-72 h collection interval). Urinary excretion accounted for about 30% of the dose and occurred very rapidly (about 22% of the dose was in the 0-8 h collection interval). Metabolic investigations were carried out on urine samples. TLC analysis with radioscan detector indicated a main radioactive zone, accounting for about 98% of the radioactivity in the plate. After scraping off and purification of the radioactive areas, the compound isolated (Met I) was analysed by gas chromatography-mass spectrometry with electron-impact ionization process. The structure of the metabolite was postulated to be pyrrolidine N-oxide.

  7. Adsorption of La(III) in aqueous systems by N-(2-hydroxyethyl) salicylaldimine-functionalized mesoporous silica

    SciTech Connect

    Tadjarodi, Azadeh Jalalat, Vahideh; Zare-Dorabei, Rouholah

    2015-01-15

    Highlights: • HESI-SBA-15 as a new adsorbent was synthesized for the first time. • This adsorbent was selective for lanthanum ion removal in presence of other ions. • The factors that affected adsorption of La(III) in aqueous solution were studied. • La{sup 3+} uptake process was according to pseudo-second-order kinetic model. - Abstract: In this work, a novel modified SBA-15 with covalently bonded N-(2-hydroxyethyl) salicylaldimine Schiff base as a ligand (HESI-SBA-15) was successfully synthesized, characterized and used as a selective absorbent for lanthanum ions removal from water systems. The structure and physicochemical properties were identified by elemental analysis, X-ray diffraction, nitrogen adsorption–desorption, thermogravimetric analysis and FTIR spectroscopy, scanning electron microscopy, BET surface area and BJH pore size. These techniques have confirmed that the Schiff base ligand was successfully grafted on the SBA-15 surface and ordered arrangement of the silica support was preserved under functionalization. The effect of pH, adsorbent dose, contact time, ionic strength and initial metal ions concentration were studied by using a batch method. This new adsorbent showed high adsorption capacity and selectivity for lanthanum in the presence of other ions. The adsorption process was exactly according to the pseudo-second-order kinetic model. The adsorbent showed a good reusability after four cycles recovery.

  8. Isolation of immunoglobulin G from bovine milk whey by poly(hydroxyethyl methacrylate)-based anion-exchange cryogel.

    PubMed

    Dong, Shasha; Chen, Liang; Dai, Bin; Johnson, Wilfred; Ye, Jialei; Shen, Shaochuan; Yun, Junxian; Yao, Kejian; Lin, Dong-Qiang; Yao, Shan-Jing

    2013-08-01

    Bovine milk whey contains several bioactive proteins such as α-lactalbumin, β-lactoglobulin, and immunoglobulin G (IgG). Chromatographic separation of these proteins has received much attention in the past few years. In this work, we provide a chromatographic method for the efficient isolation of IgG from bovine milk whey using a poly(2-hydroxyethyl methacrylate)-based anion-exchange cryogel. The monolithic cryogel was prepared by grafting 2-(dimethylamino) ethyl methacrylate onto the poly(2-hydroxyethyl methacrylate)-based cryogel matrix and then employed to separate IgG under various buffer pH and salt elution conditions. The results showed that the buffer pH and the salt concentration in the step elution have remarkable influences on the purity of IgG, while the IgG recovery depended mainly on the loading volume of whey for a given cryogel bed. High purity IgG (more than 95%) was obtained using the phosphate buffer with pH of 5.8 as the running buffer and the salt solution in as the elution liquid. With suitable loading volume of whey, the maximum IgG recovery of about 94% was observed. The present separation method is thus a potential choice for the isolation of high-purity IgG from bovine milk whey.

  9. Poly[3-(2-hydroxyethyl)-2,5-thienylene] grafted reduced graphene oxide: an efficient alternate material of TiO2 in dye sensitized solar cells.

    PubMed

    Chatterjee, Shreyam; Patra, Astam K; Bhaumik, Asim; Nandi, Arun K

    2013-05-21

    Replacement of the TiO2 layer in a traditional dye sensitized solar cell (DSC) by poly[3-(2-hydroxyethyl)-2,5-thienylene] grafted reduced graphene oxide (PHET-g-rGO) yields an overall power conversion efficiency of 3.06% with the N-719 dye, where the rGO part increases the charge mobility by reducing the backward recombination reaction in the DSC.

  10. Synthesis of some novel azo derivatives of 3,5-dimethyl-1-(2-hydroxyethyl)pyrazole as potent analgesic agents.

    PubMed

    Oruç, E E; Koçyigit-Kaymakçioglu, B; Oral, B; Altunbas-Toklu, H Z; Kabasakal, L; Rollas, S

    2006-05-01

    A series of 1-(2-hydroxyethyl)-3,5-dimethylpyrazolylazo derivatives, incorporating thiosemicarbazide 2a-c, 1,3,4-thiadiazole 3a-c, and 1,2,4-triazole-3-thione 4a-c were synthesized. The structure of these novel synthesized compounds 2a-c, 3a-c, and 4a-c was confirmed by spectral analysis. All these compounds were screened for their analgesic activity. Hot-plate and tail-immersion tests were used for the determination of the analgesic activity. Morphine, an analgesic through both spinal and supraspinal pathways, was used as a standard test drug. All compounds were administered at a dose of 100 mg/kg i.p. Among the compounds, 2-(butylamino)-5-[((1-(2-hydroxyethyl)-3,5-dimethylpyrazole-4-yl)azo)phenyl]-1,3,4-thiadiazole 3a and 4-[((1-(2-hydroxyethyl)-3,5-dimethylpyrazole-4-yl)azo)phenyl]-4-(2-phenethyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione 4c showed analgesic effects in both tests. Especially 4c exerted strong analgesia starting at 30 min after injection.

  11. Cordycepin and N6-(2-Hydroxyethyl)-Adenosine from Cordyceps pruinosa and Their Interaction with Human Serum Albumin

    PubMed Central

    Meng, Zebin; Kang, Jichuan; Wen, Tingchi; Lei, Bangxing; Hyde, Kevin David

    2015-01-01

    Cordyceps pruinosa (CP) is often used as Traditional Chinese Medicine, but the substance basis of its medicinal properties is unclear. In this study, two compounds were isolated from CP cultures by column chromatography, and identified as cordycepin and N6-(2-hydroxyethyl)-adenosine (HEA) by Nuclear Magnetic Resonance. In order to understand the efficacy of these two substances as potential therapeutic agents, it is necessary to explore their binding with proteins. The molecular mechanisms of interaction between cordycepin, HEA and human serum albumin (HSA) were studied using UV and fluorescence spectroscopy. The bingding constants between HSA and cordycepin were 4.227, 3.573 and 3.076 × 103·at 17, 27 and 37°C respectively, and that of HSA and HEA were 27.102, 19.409 and 13.002 × 103·at the three tempretures respectively. Both cordycepin and HEA can quench the intrinsic fluorescence of HSA via static quenching, and they can bind with HSA to form complexes with a single binding site. The interaction forces between cordycepin and HSA were determined as electrostatic and hydrophobic, and those of HEA and HSA were hydrogen bonding and van der Waals forces. Using Foster's equation, the distance between fluorophores of cordycepin and HSA, and HEA and HSA are estimated to be 5.31 nm and 4.98 nm, respectively. In this study, cordycepin was isolated for the first time from CP, and will provide a new source of cordycepin and expand the use of this taxon. The interaction mechanisms between cordycepin and HSA was studied for the first time, which will provide a useful guide for the clinical application of cordycepin. The pharmacological importance of this study is to understand the interaction of HSA with cordycepin and HEA, which will be essential for the future designing of drugs based on the two compounds. PMID:25811172

  12. Critical appraisal. Current usage of glutaraldehyde/HEMA.

    PubMed

    Boksman, Leendert Len; Swift, Edward J

    2011-12-01

    The use of glutaraldehyde/2-hydroxyethylmethacrylate (HEMA) combinations has been recommended for routine use in restorative dentistry by many authors and opinion leaders. Clinical restorative sites are colonized by bacteria that can contribute to postoperative sensitivity or recurrent caries. The structure of dentin allows for fluid conductance, which has been identified by Brännström as the cause of dentin sensitivity and as well, its water content challenges short- and long-term adhesion. The glutaraldehyde/HEMA combination is stated to be antimicrobial, a flocculating agent that strengthens collagen, and an agent that can create tubular occlusion, thereby reducing postoperative sensitivity by limiting fluid movement without affecting the strength of bonding or adhesive cements. This Critical Appraisal reviews five publications that deal with the various issues and clinical challenges described above, and provides suggestions for additional reading. A Bottom Line summary is provided.

  13. Preparation and characterization of infection-resistant antibiotics-releasing hydrogels rods of poly[hydroxyethyl methacrylate-co-(poly(ethylene glycol)-methacrylate]: biomedical application in a novel rabbit penile prosthesis model.

    PubMed

    Arica, M Yakup; Tuğlu, Devrim; Başar, M Murad; Kiliç, Dilek; Bayramoğlu, Gülay; Batislam, Ertan

    2008-07-01

    In this work, preparation and characterization of novel three different antibiotic loaded penile prosthesis in the rod form were investigated by copolymerization of 2-hydroxyethylmethacrylate (HEMA) with poly(ethylene glycol)-methacrylate, (PEG-MA). To achieve this goal, a series of novel copolymer hydrogels were prepared in rod form using HEMA and PEG-MA monomers via UV initiated photopolymerization. The thermal stability of the copolymer was found to be lowered by increase in the ratio of PEG-MA in the rod structure. Contact angle measurements on the surface of copolymer hydrogel demonstrated that the copolymer gave rise to a significant hydrophilic surface compared with pure poly(HEMA). The blood protein adsorption and platelet adhesion were significantly reduced on the surface of the copolymer hydrogels compared with control pure poly(HEMA). Poly(HEMA:PEG-MA;1:1)-1 formulation containing different antibiotics (20 mg antibiotic/g polymer) released about 90, 91, and 55% of the total loaded cephtriaxon, vancomycin, and gentamicin in 48 h at pH 7.4, respectively. Finally, antibiotics loaded biocompatible poly(HEMA:PEG-MA;1:1)-1 hydrogel compositions was used as a penile prosthesis in preventing cavernous tissue infections in a rabbit prosthesis model. The efficacy of the three different antibiotics loaded hydrogel system was evaluated in four different groups of rabbits, in which various infectious agents were inoculated. The animals were sacrificed after predetermined time periods, and clinical, histological and microbiological assessment on the implant side were carried out to detect infections. Eventually, we concluded that three different antibiotic loaded penile prostheses (i.e. poly(HEMA:PEG-MA;1:1)-1 hydrogel systems) were as effective as parenteral antibiotics applications.

  14. 40 CFR 721.10526 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated... methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated (generic). (a) Chemical substance and...-(hydroxymethyl)-2-methyl-2-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2′-...

  15. 40 CFR 721.10526 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated... methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated (generic). (a) Chemical substance and...-(hydroxymethyl)-2-methyl-2-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2′-...

  16. Crosslinked superhydrophobic films fabricated by simply casting poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-poly(perfluorohexylethyl methacrylate) solution

    NASA Astrophysics Data System (ADS)

    Wen, Xiufang; Ye, Chao; Cai, Zhiqi; Xu, Shouping; Pi, Pihui; Cheng, Jiang; Zhang, Lijuan; Qian, Yu

    2015-06-01

    This study focuses on the preparation of superhydrophobic films by crosslinkable polymer material-Poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-Poly(perfluorohexylethyl methacrylate) (P (MMA-BA-HEMA)-b-PFMA) with a simple one-step casting process. Nanoscale micelle particles with core-shell structure was obtained by dissolving the polymer and curing agent in the mixture of acetone and 1H, 1H, 5H octafluoropentyl-1,1,2,2 tetrafluoroethyl ether (FHT). Superhydrophobic films were fabricated by casting the micelle solution on the glass slides. By controlling the polymer concentration and acetone/FHT volume ratio, superhydrophobic polymer film with water contact angle of 153.2 ± 2.1° and sliding angle of 4° was obtained. By introducing a curing agent into the micelle solution, mechanical properties of the films can be improved. The adhension grade and hardness of the crosslinked superhydrophobic films reached 2 grade and 3H, respectively. The hydrophobicity is attributed to the synergistic effect of micro-submicro-nano-meter scale roughness by nanoscale micelle particles and low surface energy of fluoropolymer. This procedure makes it possible for widespread applications of superhydrophobic film due to its simplicity and practicability.

  17. Cloning and characterization of the hemA region of the Bacillus subtilis chromosome.

    PubMed Central

    Petricek, M; Rutberg, L; Schröder, I; Hederstedt, L

    1990-01-01

    A 3.8-kilobase DNA fragment from Bacillus subtilis containing the hemA gene has been cloned and sequenced. Four open reading frames were identified. The first is hemA, encoding a protein of 50.8 kilodaltons. The primary defect of a B. subtilis 5-aminolevulinic acid-requiring mutant was identified as a cysteine-to-tyrosine substitution in the HemA protein. The predicted amino acid sequence of the B. subtilis HemA protein showed 34% identity with the Escherichia coli HemA protein, which is known to code for the NAD(P)H:glutamyl-tRNA reductase of the C5 pathway for 5-aminolevulinic acid synthesis. The B. subtilis HemA protein also complements the defect of an E. coli hemA mutant. The second open reading frame in the cloned fragment, called ORF2, codes for a protein of about 30 kilodaltons with unknown function. It is not the proposed hemB gene product porphobilinogen synthase. The third open reading frame is hemC, coding for porphobilinogen deaminase. The fourth open reading frame extends past the sequenced fragment and may be identical to hemD, coding for uroporphyrinogen III cosynthase. Analysis of deletion mutants of the hemA region suggests that (at least) hemA, ORF2, and hemC may be part of an operon. Images PMID:2110138

  18. Hyperbranched Polymers by Type II Photoinitiated Self-Condensing Vinyl Polymerization.

    PubMed

    Aydogan, Cansu; Ciftci, Mustafa; Yagci, Yusuf

    2016-04-01

    Type II photoinitiated self-condensing vinyl polymerization for the preparation of hyperbranched polymers is explored using 2-hydroxyethyl methacrylate (HEMA) or 2-(dimethylamino)ethyl methacrylate (DMAEMA), and methyl methacrylate as hydrogen donating inimers and comonomer, respectively, in the presence of benzophenone and camphorquinone under UV and visible light. Upon irradiation at the corresponding wavelength, the excited photoinitiator abstracts hydrogen from HEMA or DMAEMA leading to the formation of initiating radicals. Depending on the concentration of inimers, type of the photoinitiator, and irradiation time, hyperbranched polymers with different branching densities and cross-linked polymers are formed.

  19. Acrylates and Methacrylates,

    DTIC Science & Technology

    1987-09-15

    of ethylene and hydrocyanic acid through ethylene cyanohydrin. In the presence of basic catalysts ethylene oxide easily adds hydrocyanic acid with the...of synthesis of methacrylates. At present methacrylates are obtained in the industry by continuous method from acetone and hydrocyanic acid through...acetone cyanohydrin. The addition/connection to it of hydrocyanic acid with the formation of acetone cyanohydrin is one of the most important reactions

  20. Development of a competitive immunoassay for the determination of N-(2-hydroxyethyl)valine adducts in human haemoglobin and its application in biological monitoring.

    PubMed

    Ball, Lathan; Jones, Alan; Boogaard, Peter; Will, Wolfgang; Aston, Paul

    2004-01-01

    Ethylene oxide (EO) is an important industrial compound and a directly acting mutagen. Human exposure to it can be monitored by the determination of haemoglobin (Hb) adducts. An immunoassay that quantifies the N-terminal adduct N-(2-hydroxyethyl)valine in whole blood was developed, and its potential usefulness as a tool for biologically monitoring occupational exposure demonstrated. Analytical reliability was confirmed in a comparative study with gas chromatography-mass spectrometry (range 0.040-589 nmol g(-1) Hb, correlation coefficient 0.98, n=10). The assay was configured as a competitive enzyme-linked immunosorbent assay to facilitate the rapid throughput of samples. The assay uses a whole blood matrix and has a working range of 10-10000 pmol N-(2-hydroxyethyl)valine g(-1) hB. The assay does not appear to be affected by structurally similar metabolites and has been used to determine adducts in human blood samples. The first results from potentially exposed workers indicate the assay might be a powerful tool for the routine occupational biomonitoring of EO exposure.

  1. Synthesis and Characterization of Multiwalled Carbon Nanotubes/Poly(HEMA-co-MMA) by Utilizing Click Chemistry.

    PubMed

    Bach, Long Giang; Cao, Xuan Thang; Islam, Md Rafiqul; Jeong, Yeon Tae; Kim, Jong Su; Lim, Kwon Taek

    2016-03-01

    The hybrid material consisting of multi walled carbon nanotubes (MWNTs) and poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) [poly(HEMA-co-MMA)] was synthesized by a combination of RAFT and Click chemistry. In the primary stage, the copolymer poly(HEMA-co-MMA) was prepared by applying RAFT technique. Alkynyl side groups were incorporated onto the poly(HEMA-co-MMA) backbone by esterification reaction. Then, MWNTs-N3 was prepared by treating MWNTs with 4-azidobutylamine. The click coupling reaction between azide-functionalized MWNTs (MWNTs-N3) and the alkyne-functionalized random copolymer ((HEMA-co-MMA)-Alkyne) with the Cu(I)-catalyzed [3+2] Huisgen cycloaddition afforded the hybrid compound. The structure and properties of poly(MMA-co-HEMA)-g-MWNTs were investigated by FT-IR, EDX and TGA measurements. The copolymer brushes were observed to be immobilized onto the functionalized MWNTs by SEM and TEM analysis.

  2. Dynamic wettability of pHEMA-based hydrogel contact lenses.

    PubMed

    Maldonado-Codina, Carole; Efron, Nathan

    2006-07-01

    Standard methods of contact angle analysis include sessile drop, captive bubble and Wilhelmy plate techniques; however, these methodologies are not particularly well suited for assessing the wettability of the surfaces of formed hydrogel contact lenses. This paper describes two methodologies that are adaptations of previously described techniques. The maximum adherent force method is an adaptation of the dynamic Wilhelmy plate technique that allows the assessment of whole, finished contact lenses. The dynamic photographic method allows the simultaneous assessment of the front and back surfaces of strip samples for the assessment of advancing and receding contact angles. Lenses investigated were made from polyhydroxyethyl methacrylate, hydroxyethyl methacrylate/methacrylic acid and hydroxyethyl methacrylate/glycerol methacrylate. The lenses were manufactured by lathing, spin-casting or cast-moulding techniques. Overall, both techniques demonstrated few differences between the wettability of different lens materials and no differences between materials of the 'same' lens type but manufactured by different methods. These findings are consistent with the results of clinical studies, which have shown little difference between contact lens surface wettability in vivo, which may be due to the apparent natural surface wettability-enhancing properties of the pre-lens tear film.

  3. Design of poly(vinylidene fluoride)-g-p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) membrane via surface modification for enhanced fouling resistance and release property

    NASA Astrophysics Data System (ADS)

    Zhao, Guili; Chen, Wei Ning

    2017-03-01

    Thermo-sensitive polymer poly(N-isopropylacrylamide) (PNIPAAm), hydrophilic polymer poly(hydroxyethyl methacrylate) (PHEMA) and copolymer p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) [P(HEMA-co-NIPAAm)] were synthesized onto poly(vinylidene fluoride) (PVDF) membrane via atom transfer radical polymerization (ATRP) in order to improve not only fouling resistance but also fouling release property. The physicochemical properties of membranes including hydrophilicity, morphology and roughness were examined by contact angle analyzer, scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. The antifouling property of membranes was improved remarkably after surface modification according to protein and bacterial adhesion testing, and filtration experiment. Minimum protein adsorption and bacterial adhesion were both obtained on PVDF-g-P(HEMA-co-NIPAAm) membrane, with reduction by 44% and 71% respectively compared to the pristine membrane. The minimum bacterial cells after detachment at 25 °C were observed on the PVDF-g-P(HEMA-co-NIPAAm) membrane with the detachment rate of 77%, indicating high fouling release property. The filtration testing indicated that the copolymer modified membrane exhibited high resistance to protein fouling and the foulant on the surface was released and removed easily by washing, suggesting high fouling release and easy-cleaning capacity. This study provides useful insight in the combined "fouling resistance" and "fouling release" property of P(HEMA-co-NIPAAm) for PVDF membrane modification, even for other types of the membrane in wide application.

  4. Radiation-grafting of 2-hydroxyethylmethacrylate and oligo (ethylene glycol) methyl ether methacrylate onto polypropylene films by one step method

    NASA Astrophysics Data System (ADS)

    Ramírez-Jiménez, Alejandro; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Bucio, Emilio

    2012-01-01

    Polypropylene films were modified with 2-hydroxyethylmethacrylate (HEMA) and oligo (ethylene glycol) methyl ether methacrylate (OEGMA) using the pre-irradiation method with gamma-rays (one step method). The effect of absorbed dose from 10 to 100 kGy, temperature (50, 60, and 70 °C), monomer concentration between 12.5% and 62.5%, monomers ratio from 10% to 90% and reaction time from 5 to 50 h; on the degree of grafting was determined. The grafted samples were analyzed by FTIR-ATR, TGA, DSC, swelling, and contact angle. Grafts onto polymeric films between 3% and 109% were obtained at doses from 10 to 100 kGy and a dose rate around 7.4 kGy/h. The graft percent increased with the content in HEMA in the HEMA:OEGMA feed mixture, which indicates a lower reactivity of OEGMA compared to HEMA. The hydrogel layer grafted on the polypropylene substrate increases the hydrophilicity of the surface and also provides certain temperature-responsiveness, which may be of interest for biomedical applications.

  5. Controlled release of curcumin from poly(HEMA-MAPA) membrane.

    PubMed

    Caka, Müşerref; Türkcan, Ceren; Aktaş Uygun, Deniz; Uygun, Murat; Akgöl, Sinan; Denizli, Adil

    2017-05-01

    In this work, poly(HEMA-MAPA) membranes were prepared by UV-polymerization technique. These membranes were characterized by SEM, FTIR, and swelling studies. Synthesized membranes had high porous structure. These membranes were used for controlled release of curcumin which is already used as folk remedy and used as drug for some certain diseases and cancers. Curcumin release was investigated for various pHs and temperatures. Optimum drug release yield was found to be as 70% at pH 7.4 and 37 °C within 2 h period. Time-depended release of curcumin was also investigated and its slow release from the membrane demonstrated within 48 h.

  6. Thermoforming polymethyl methacrylate.

    PubMed

    Jagger, R G; Okdeh, A

    1995-11-01

    This study characterized a range of commercially available polymethyl methacrylate sheets with respect to molecular weight, residual monomer content, and glass transition temperature and then developed a thermoforming procedure that produced visually satisfactory thermoformed polymethyl methacrylate specimens. Molecular weight values of Perspex material were considerably greater than those of the other materials. All materials but Diakon had residual monomer concentrations of less than 1% and glass transition temperature values greater than 100 degrees C. Perspex material was selected for further investigation. It was necessary to preheat Perspex sheets in an oven at 160 degrees C for at least 30 minutes before heating and forming on the thermoforming apparatus to obtain acceptable specimens.

  7. Structure-Based Design, Synthesis, and Evaluation of 2'-(2-Hydroxyethyl)-2'-deoxyadenosine and the 5'-Diphosphate Derivative as Ribonucleotide Reductase Inhibitors

    SciTech Connect

    Sun, D.; Xu, H.; Wijerathna, S.R.; Dealwis, C.; Lee, R.E.

    2010-08-27

    Analysis of the recently solved X-ray crystal structures of Saccharomyces cerevisiae ribonucleotide reductase I (ScRnr1) in complex with effectors and substrates led to the discovery of a conserved water molecule located at the active site that interacted with the 2'-hydroxy group of the nucleoside ribose. In this study 2'-(2-hydroxyethyl)-2'-deoxyadenosine 1 and the 5'-diphosphate derivative 2 were designed and synthesized to see if the conserved water molecule could be displaced by a hydroxymethylene group, to generate novel RNR inhibitors as potential antitumor agents. Herein we report the synthesis of analogues 1 and 2, and the co-crystal structure of adenosine diphosphate analogue 2 bound to ScRnr1, which shows the conserved water molecule is displaced as hypothesized.

  8. Copolymers of ethylene imine and N-(2-hydroxyethyl)-ethylene imine as tools to study effects of polymer structure on physicochemical and biological properties of DNA complexes.

    PubMed

    Fischer, Dagmar; von Harpe, Anke; Kunath, Klaus; Petersen, Holger; Li, Youxin; Kissel, Thomas

    2002-01-01

    A series of five poly[(ethylene imine)-co-N-(2-hydroxyethyl-ethylene imine)] copolymers with similar molecular weights and different degrees of branching was established to study structure-function relationship with regard to physicochemical and biological properties as gene delivery systems. Copolymers were synthesized by acid-catalyzed ring-opening copolymerization of aziridine and N-(2-hydroxyethyl)-aziridine in aqueous solution and characterized by GPC-MALLS, (1)H- and (13)C NMR, IR, potentiometric titration, and ion exchange chromatography. Complexation of DNA was determined by agarose gel electrophoresis, and complex sizes were quantitated by PCS. Cytotoxicity of the copolymers in fibroblasts was assessed by MTT-assay, LDH-assay, and hemolysis. The transfection efficiency was determined using the reporter plasmid pGL3 in 3T3 mouse fibroblasts. The copolymers obtained by solution polymerization had relatively low molecular weights of about 2000 Da, and the degree of branching increased with increasing ethylene imine ratio. The pK(a) as well as the buffer capacity increased proportional to the number of primary and secondary amines. Higher branched polymers showed stronger complexation and condensation of DNA, formed smaller polymer/DNA complexes, and induced the expression of plasmids to a higher extent than less branched polymers. In vitro cytotoxic effects and the hemolysis of erythrocytes decreased with decreased branching. Our results indicate that the basicity and degree of protonation of the polymers depending on their amount of primary and secondary amines seem to be important factors both for their transfection efficiency and for their cytotoxicity in gene transfer.

  9. Relations between photophysical and lasing properties of rhodamines in solid polymeric matrices

    NASA Astrophysics Data System (ADS)

    López Arbeloa, F.; López Arbeloa, T.; López Arbeloa, I.; Costela, A.; García-Moreno, I.; Figuera, J. M.; Amat-Guerri, F.; Sastre, R.

    1996-06-01

    The photophysical properties of Rhodamine 6G derivatives with different substituents in the ester group, in solid solutions of copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) or covalently bound to the same polymeric chains, have been determined and compared with the lasing properties of the materials under irradiation with 337 nm (N2 laser) pulses. In these solid media the rhodamine chromophore shows a photophysical behaviour similar to that in a liquid solution, and its photostability clearly increases when the chromophore is bound to the polymeric chain. These new solid materials show laser efficiencies that depend on the HEMA/MMA ratio, in some cases with values close to 20%.

  10. Procion red MX-3B-derived poly(HEMA/EGDMA) microspheres for removal of cadmium ions

    SciTech Connect

    Denizli, A.; Bueyuektuncel, E.; Genc, O.; Piskin, E.

    1998-12-01

    The heavy metal pollution is becoming more and more serious an environmental problem throughout the world due to rapid industrialization. Heavy metals such as cadmium and mercury exhibit human toxicity at extremely low concentrations. Poly(hydroxyethyl methacrylate/ethylene glycol dimethacrylate) [poly(HEMA/EGDMA)]-Procion Red MX-3B microspheres were used for removal of Cd(II) ions from aqueous solutions containing different amounts of Cd(II) ions (5--60 ppm). Dye-derived microbeads carrying 8.95 {micro}mol Procion Red MX-3B/g polymer were used in the adsorption-desorption of Cd(II) ions. High adsorption rates were observed at the beginning of adsorption and then equilibrium was achieved in about 5--10 min. The maximum adsorption of Cd(II) ions onto the Procion Red MX-3B-derived microspheres (i.e., by chelate formation of Cd(II) ions with dye molecules) was about 4.2 mg Cd(II) ions/g polymer, which was observed at pH 7.0. While non-specific adsorption onto the underived microspheres was 0.93 mg Cd(II) ions/g polymer. More than 96% of the adsorbed Cd(II) ions was desorbed in 15 min by using 0.1 M HNO{sub 3} as an desorption agent. The regenerability of the dye-derived atmospheres was also sufficient.

  11. Preparation of poly(methyl methacrylate) grafted titanate nanotubes by in situ atom transfer radical polymerization

    NASA Astrophysics Data System (ADS)

    Gao, Yuan; Gao, Xueping; Zhou, Yongfeng; Yan, Deyue

    2008-12-01

    This paper reports the successful preparation of core-shell hybrid nanocomposites by a 'grafting from' approach based on in situ atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) from titanate nanotubes (TNTs). Transmission electron microscope (TEM) images of the products provide direct evidence for the formation of a core-shell structure, possessing a hard core of TNTs and a soft shell of poly-MMA (PMMA). Fourier-transform infrared spectroscopy (FT-IR), hydrogen nuclear magnetic resonance (1H NMR), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA) were used to determine the chemical structure, morphology, and the grafted PMMA quantities of the resulting products. The grafted PMMA content was well controlled and increased with increasing monomer/initiator ratio. Further copolymerization of hydroxyethyl methacrylate (HEMA) with PMMA-coated TNTs as initiators was realized, illustrating the 'living' characteristics of the ATRP method used in this paper.

  12. Facile construction of dual bandgap optical encoding materials with PS@P(HEMA-co-AA)/SiO2-TMPTA colloidal photonic crystals

    NASA Astrophysics Data System (ADS)

    Tian, Yu; Zhang, Jing; Liu, Si-Si; Yang, Shengyang; Yin, Su-Na; Wang, Cai-Feng; Chen, Li; Chen, Su

    2016-07-01

    An operable strategy for the construction of dual-reflex optical code materials from bilayer or Janus-structure colloidal photonic crystals (CPCs) has been established in this work. In this process, monodispersed submicrometer polystryene@poly(2-hydroxyethyl methacrylate-co-acrylic acid) hydrogel microspheres with soft-shell/hard-core structure and monodispersed colloidal silica spheres were fabricated. These two kinds of colloidal units can be facilely integrated into a single material without optical signal interference because they are well isolated for the immiscibility between water and ethoxylated trimethylolpropane triacrylate (TMPTA) and the upper layer of SiO2-TMPTA is a kind of transparent. Moreover, diverse optical code series with different dual photonic bandgaps can be obtained via tuning the colloid sizes. Compared to the conventional single-reflex CPCs, the as-prepared dual-reflex optical code materials represented high information capacity in encoding process. More interesting, delicate code pattern has been also achieved on the optical film via the silk-screen printing technique, which will greatly extend the dual-reflex optical code materials to practical uses in areas containing bio-encoding, anti-counterfeiting, and flexible displays.

  13. Innovative hydrogels based on semi-interpenetrating p(HEMA)/PVP networks for the cleaning of water-sensitive cultural heritage artifacts.

    PubMed

    Domingues, Joana A L; Bonelli, Nicole; Giorgi, Rodorico; Fratini, Emiliano; Gorel, Florence; Baglioni, Piero

    2013-02-26

    Water-based detergent systems offer several advantages, over organic solvents, for the cleaning of cultural heritage artifacts in terms of selectivity and gentle removal of grime materials or aged varnish, which are known to alter the readability of the painting. Unfortunately, easel paintings present specific characteristics that make the usage of water-based systems invasive. The interaction of water with wood or canvas support favors mechanical stresses between the substrate and the paint layers leading to the detachment of the pictorial layer. In order to avoid painting loss and to ensure a fine control (layer by layer) of grime removal, water-based cleaning systems have been confined into innovative chemical hydrogels, specifically designed for cleaning water-sensitive cultural heritage artifacts. The synthesized hydrogels are based on semi-interpenetrating chemical poly(2-hydroxyethyl methacrylate)/poly(vinylpyrrolidone) networks with suitable hydrophilicity, water retention properties, and required mechanical strength to avoid residues after the cleaning treatment. Three different compositions were selected. Water retention and release properties have been studied by quantifying the amount of free and bound water (from differential scanning calorimetry); mesoporosity was obtained from scanning electron microscopy; microstructure from small angle X-ray scattering. To demonstrate both the efficiency and versatility of the selected hydrogels in confining and modulating the properties of cleaning systems, a representative case study is presented.

  14. Amphiphilic Comb-Shaped Diblock Polymer Brushes on Si(100) Substrates via Surface-Initiated Atom Transfer Radical Polymerization

    NASA Astrophysics Data System (ADS)

    Peng, Jin-Wen; Huang, Wei; Kang, En-Tang; Neoh, Koon Gee

    Amphiphilic comb-shaped 2-hydroxyethyl methacrylate-graft-poly(styrene)-block-poly(poly (ethylene glycol) monomethacrylate) (P(HEMA)-g-PS-b-P(PEGMA)) copolymer brushes, covalently tethered on Si(100) substrate, have been successfully prepared by (i) UV-induced hydrosilylation of 4-vinylbenzyl chloride (VBC) with the hydrogen-terminated Si(100) (Si-VBC surface), (ii) surface-initiated atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate (HEMA) to give the Si-VBC-g-P(HEMA) surface, (iii) coupling of 2-bromoisobutyryl bromide with the HEMA units via esterification to provide the comb-shaped macroinitiators (Si-VBC-g-P(HEMA)-R3Br) for the subsequent ATRP, (iv) surface-initiated ATRP of styrene (St) to produce the Si-VBC-g-P(HEMA)-g-PS surface, and (v) the persisting of an active PS chain end can be used as the initiator for the subsequent ATRP of poly(ethylene glycol) monomethacrylate (PEGMA) to give the amphiphilic Si-VBC-g-P(HEMA)-g-PS-b-P(PEGMA) brush surface. The chemical composition and functionality of the silicon surface were tailored by the well-defined comb-shaped PS and P (PEGMA) brushes.

  15. Non-thermal atmospheric plasma brush induces HEMA grafting onto dentin collagen

    PubMed Central

    Chen, Mingsheng; Zhang, Ying; Dusevich, Vladimir; Liu, Yi; Yu, Qingsong; Wang, Yong

    2014-01-01

    Objective Non-thermal atmospheric plasma (NTAP) brush has been regarded as a promising technique to enhance dental interfacial bonding. However, the principal enhancement mechanisms have not been well identified. In this study, the effect of non-thermal plasmas on grafting of HEMA, a typical dental monomer, onto dentin collagen thin films was investigated. Methods Human dentin was sectioned into 10-um-thick films. After total demineralization in 0.5 M EDTA solution for 30 min, the dentin collagen films were water-rinsed, air-dried, treated with 35 wt% HEMA aqueous solution. The films were then subject to plasma-exposure under a NTAP brush with different time (1–8 min) / input power (5–15 w). For comparison, the dentin collagen films were also treated with the above HEMA solution containing photo-initiators, then subject to light-curing. After plasma-exposure or light-curing, the HEMA-collagen films were rinsed in deionized water, and then examined by FTIR spectroscopy and TEM. Results The FITR results indicated that plasma-exposure could induce significant HEMA grafting onto dentin collagen thin films. In contrast, light-curing led to no detectable interaction of HEMA with dentin collagen. Quantitative IR spectral analysis (i.e., 1720/3075 or 749/3075, HEMA/collagen ratios) further suggested that the grafting efficacy of HEMA onto the plasma-exposed collagen thin films strongly depended on the treatment time and input power of plasmas. TEM results indicated that plasma treatment did not alter collagen’s banding structure. Significance The current study provides deeper insight into the mechanism of dental adhesion enhancement induced by non-thermal plasmas treatment. The NTAP brush could be a promising method to create chemical bond between resin monomers and dentin collagen. PMID:25458523

  16. Detection of leachables and cytotoxicity after exposure to methacrylate- and epoxy-based root canal sealers in vitro.

    PubMed

    Lodienė, Greta; Kopperud, Hilde M; Ørstavik, Dag; Bruzell, Ellen M

    2013-10-01

    Root canal sealing materials may have toxic potential in vitro depending on the cell line, cytotoxicity assay, material chemistry, and degree of polymer curing. The aims of the present study were to detect leaching components from epoxy- or methacrylate-based root canal sealers and to investigate the degree of cytotoxicity after exposure to extracts from these materials. Qualitative determination of substances released from the materials was performed by gas- and liquid chromatography/mass spectrometry. Submandibular salivary gland acinar cell death (apoptosis/necrosis) was determined using a fluorescence staining/microscopy technique. The major leachable monomer from the epoxy-based material was bisphenol-A diglycidyl ether (BADGE), whereas leachables from the methacrylate-based materials were mainly triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and polyethyleneglycol dimethacrylate (PEGDMA). Exposure to diluted extracts of cured methacrylate-based materials caused a postexposure time-dependent increase in cell death. This effect was not demonstrated as a result of exposure to undiluted extract of cured epoxy-based material. Extracts of all fresh materials induced apoptosis significantly, but at lower dilutions of the epoxy- than the methacrylate-based materials. The degree of leaching, determined from the relative chromatogram peak heights of eluates from the methacrylate-based sealer materials, corresponded with the degree of cell death induced by extracts of these materials.

  17. Synthesis and characterization of a noncytotoxic, X-ray opaque polyurethane containing iodinated hydroquinone bis(2-hydroxyethyl) ether as chain extender for biomedical applications.

    PubMed

    Kiran, S; Joseph, Roy

    2014-09-01

    An iodinated urethane polymer that does not require addition of X-ray attenuating additives to impart X-ray opacity was synthesized and characterized for biomedical applications. A new X-ray opaque diiodo compound, namely, 2,2'-(2,5-diiodobenzene-1,4-diyl)bis(oxy)diethanol (DBD), was synthesized by iodinating hydroquinone bis(2-hydroxyethyl) ether and this compound was used as chain extender during polyurethane synthesis so that X-ray opacity could be imparted to the polymer formed. X-ray opaque polyurethane (XPU) was synthesized by reacting 1,6-diisocyanatohexane with poly(hexamethylene carbonate)diol and DBD. X-ray opacity of XPU was measured with a fluoroscopy machine using BaSO4 -filled polyurethane as controls. Radiographic images showed that XPU sample had X-ray opacity equivalent to 15 wt % BaSO4-filled polymer. In vivo imaging in a rabbit model showed that the material could be readily distinguishable from bones. XPU was found to be hemocompatible and noncytotoxic to L929 fibroblast cell lines. Optical transparency measurements using ultraviolet-visible spectrophotometer showed that XPU transmitted 85% of visible light.

  18. Polymorph of {2-[(2-hydroxyethyl)iminiomethyl]phenolato-kappaO}dioxido{2-[(2-oxidoethyl)iminomethyl]phenolato-kappa3O,N,O'}molybdenum(VI).

    PubMed

    Agustin, Dominique; Daran, Jean Claude; Poli, Rinaldo

    2008-02-01

    A second polymorphic form (form I) of the previously reported compound {2-[(2-hydroxyethyl)iminiomethyl]phenolato-kappaO}dioxido{2-[(2-oxidoethyl)iminomethyl]phenolato-kappa(3)O,N,O'}molybdenum(VI) (form II), [Mo(C(9)H(9)NO(2))O(2)(C(9)H(11)NO(2))], is presented. The title structure differs from the previously reported polymorph [Głowiak, Jerzykiewicz, Sobczak & Ziółkowski (2003). Inorg. Chim. Acta, 356, 387-392] by the fact that the asymmetric unit contains three molecules linked by O-H...O hydrogen bonds. These trimeric units are further linked through O-H...O hydrogen bonds to form a chain parallel to the [111] direction. As in the previous polymorph, each molecule is built up from an MoO(2)(2+) cation surrounded by an O,N,O'-tridentate ligand (O(-)C(6)H(4)CH=NCH(2)CH(2)O(-)) and weakly coordinated by a second zwitterionic ligand (O(-)C(6)H(4)CH=N(+)HC(2)H(4)OH). All complexes are chiral with the absolute configuration at Mo being C or A. The main difference between the two polymorphs results from the alternation of the chirality at Mo within the chain.

  19. Structural, crystal structure, Hirshfeld surface analysis and physicochemical studies of a new chlorocadmate template by 1-(2-hydroxyethyl)piperazine

    NASA Astrophysics Data System (ADS)

    Soudani, S.; Jeanneau, E.; Jelsch, C.; Lefebvre, F.; Ben Nasr, C.

    2016-11-01

    The synthesis, crystal structure and spectroscopic characterization of a new chlorocadmate template by the 1-(2-hydroxyethyl)piperazine ligand are reported. In the atomic arrangement, the CdCl5O entities are deployed in corrugated rows along the a-axis at y = 1/4 and y = 3/4 to form layers parallel to the (a,b) plane. In these crystals, piperazinediium cations are in a chair conformation and are inserted between these layers through Nsbnd H⋯Cl, Csbnd H⋯Cl, Osbnd H⋯Cl and Nsbnd H⋯O hydrogen bonds to form infinite three-dimensional network. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that H⋯Cl and Csbnd H⋯Hsbnd C intermolecular interactions are the most abundant contacts of the organic cation in the crystal packing. The crystal contacts enrichments reveals that, the Cd++ … Cl- salt bridges, the Cd⋯O complexation and Osbnd H⋯Cl- and Nsbnd H⋯Cl-strong H-bonds are the driving forces in the packing formation. The presence of twelve independent chloride anions and four organic cation in the asymmetric unit allowed comparing their contact propensities. The 13C and 15N CP-MAS NMR spectra are in agreement with the X-ray structure. Additional characterization of this compound has also been performed by IR spectroscopy.

  20. Ab initio and density functional theory calculations of molecular structure and vibrational spectra of 4-(2-Hydroxyethyl) piperazine-1-ethanesulfonic acid

    NASA Astrophysics Data System (ADS)

    Kumar, J. Sharmi; Devi, T. S. Renuga; Ramkumaar, G. R.; Bright, A.

    2016-01-01

    The FTIR and FT-Raman spectra of 4-(2-Hydroxyethyl) piperazine-1-ethanesulfonic acid were recorded and the structural and spectroscopic data of the molecule in the ground state were calculated using Hartree-Fock and Density Functional Method (B3LYP). The most stable conformer was optimized and the structural and vibrational parameters were determined. With the observed FTIR and FT-Raman data, a complete vibrational band assignment and analysis of the fundamental modes of the compound were carried out. Thermodynamic properties, Mulliken and natural atomic charge distribution were calculated using both Hartree-Fock and Density Functional Method and compared. UV-Visible and HOMO-LUMO analysis were carried out. 1H and 13C NMR chemical shifts of the molecule were calculated using gauge including atomic orbital method and were compared with experimental results. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital analysis. The first order hyperpolarizability (β) and molecular electrostatic potential of the molecule was computed using DFT calculations. The electron density based local reactivity descriptor such as Fukui functions were calculated to explain the chemically reactive site in the molecule.

  1. Regulation of the hemA gene during 5-aminolevulinic acid formation in Pseudomonas aeruginosa.

    PubMed Central

    Hungerer, C; Troup, B; Römling, U; Jahn, D

    1995-01-01

    The general tetrapyrrole precursor 5-aminolevulinic acid is formed in bacteria via two different biosynthetic pathways. Members of the alpha group of the proteobacteria use 5-aminolevulinic acid synthase for the condensation of succinyl-coenzyme A and glycine, while other bacteria utilize a two-step pathway from aminoacylated tRNA(Glu). The tRNA-dependent pathway, involving the enzymes glutamyl-tRNA reductase (encoded by hemA) and glutamate-1-semialdehyde-2,1-aminomutase (encoded by hemL), was demonstrated to be used by Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas stutzeri, Comamonas testosteroni, Azotobacter vinelandii, and Acinetobacter calcoaceticus. To study the regulation of the pathway, the glutamyl-tRNA reductase gene (hemA) from P. aeruginosa was cloned by complementation of an Escherichia coli hemA mutant. The hemA gene was mapped to the SpeI A fragment and the DpnIL fragment of the P. aeruginosa chromosome corresponding to min 24.1 to 26.8. The cloned hemA gene, coding for a protein of 423 amino acids with a calculated molecular mass of 46,234 Da, forms an operon with the gene for protein release factor 1 (prf1). This translational factor mediates the termination of the protein chain at the ribosome at amber and ochre codons. Since the cloned hemA gene did not possess one of the appropriate stop codons, an autoregulatory mechanism such as that postulated for the enterobacterial system was ruled out. Three open reading frames of unknown function transcribed in the opposite direction to the hemA gene were found. hemM/orf1 and orf2 were found to be homologous to open reading frames located in the 5' region of enterobacterial hemA genes. Utilization of both transcription start sites was changed in a P. aeruginosa mutant missing the oxygen regulator Anr (Fnr analog), indicating the involvement of the transcription factor in hemA expression. DNA sequences homologous to one half of an Anr binding site were detected at one of the determined

  2. Affinity purification lipase from wheat germ: comparison of hydrophobic and metal chelation effect.

    PubMed

    Köse, Kazım; Erol, Kadir; Ali Köse, Dursun; Evcı, Emre; Uzun, Lokman

    2017-05-01

    Cryogels are used quite a lot nowadays for adsorption studies as synthetic adsorbents. In this study, lipase enzyme (obtained from Candida cylindracea) adsorption capacity of poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-tryptophan), poly(HEMA-MATrp), and Cu(II) ions immobilized poly(HEMA-MATrp), poly(HEMA-MATrp)-Cu(II), cryogel membranes were synthesized to determine and compare the adsorption behavior of lipase enzyme. In this regard, the effect of pH, interaction time, lipase initial concentration, temperature and ionic strength on the adsorption capacity of these membranes was investigated. Maximum lipase enzyme adsorption capacities of poly(HEMA-MATrp) and poly(HEMA-MATrp)-Cu(II) cryogel membranes were determined as 166.4 mg/g and 196.4 mg/g, respectively.

  3. HEMA inhibits interfacial nano-layering of the functional monomer MDP.

    PubMed

    Yoshida, Y; Yoshihara, K; Hayakawa, S; Nagaoka, N; Okihara, T; Matsumoto, T; Minagi, S; Osaka, A; Van Landuyt, K; Van Meerbeek, B

    2012-11-01

    Previous research showed that the functional monomer 10-methacryloxydecyl dihydrogen phosphate (MDP) ionically bonds to hydroxyapatite (HAp) and forms a nano-layered structure at the interface with HAp-based substrates. Such hydrophobic nano-layering is considered to contribute to the long-term durability of the bond to tooth tissue. However, dental adhesives are complex mixtures usually containing different monomers. This study investigated the effect of the monomer 2-hydroxyethylmethacrylate (HEMA) on the chemical interaction of MDP with HAp by x-ray diffraction (XRD), nuclear magnetic resonance (NMR), and quartz crystal microbalance (QCM). We examined the chemical interaction of 5 experimental MDP solutions with increasing concentrations of HEMA. XRD revealed that addition of HEMA inhibits nano-layering at the interface, while NMR confirmed that MDP remained adsorbed onto the HAp surface. QCM confirmed this adsorption of MDP to HAp, as well as revealed that the demineralization rate of HAp by MDP was reduced by HEMA. It was concluded that even though the adsorption of MDP to HAp was not hindered, addition of HEMA inhibited interfacial nano-layering. Potential consequences with regard to bond durability necessitate further research.

  4. Coating process and early stage adhesion evaluation of poly(2-hydroxy-ethyl-methacrylate) hydrogel coating of 316L steel surface for stent applications.

    PubMed

    Indolfi, Laura; Causa, Filippo; Netti, Paolo Antonio

    2009-07-01

    In this study, a spray-coating method has been set up with the aim to control the coating of poly(2-hydroxy-ethyl-methacrylate) (pHEMA), an hydrophilic polymeric hydrogel, onto the complex surface of a 316L steel stent for percutaneous coronary intervention (PCI). By varying process parameters, tuneable thicknesses, from 5 to 20 microm, have been obtained with uniform and homogeneous surface without crack or bridges. Surface characteristics of pHEMA coating onto metal surface have been investigated through FTIR-ATR, contact angle measurement, SEM, EDS and AFM. Moreover, results from Single-Lap-Joint and Pull-Off adhesion tests as well as calorimetric analysis of glass transition temperature suggested that pHEMA deposition is firmly adhered on metallic surface. The pHEMA coating evaluation of roughness, wettability together with its morphological and chemical stability after three cycles of expansion-crimping along with preliminary results after 6 months demonstrates the suitability of the coating for surgical implantation of stent.

  5. The Beliefs, Myths, and Reality Surrounding the Word Hema (Blood) from Homer to the Present

    PubMed Central

    Meletis, John; Konstantopoulos, Kostas

    2010-01-01

    All ancient nations hinged their beliefs about hema (blood) on their religious dogmas as related to mythology or the origins of religion. The Hellenes (Greeks) especially have always known hema as the well-known red fluid of the human body. Greek scientific considerations about blood date from Homeric times. The ancient Greeks considered hema as synonymous with life. In Greek myths and historical works, one finds the first references to the uninterrupted vascular circulation of blood, the differences between venous and arterial blood, and the bone marrow as the site of blood production. The Greeks also speculated about mechanisms of blood coagulation and the use of blood transfusion to save life. PMID:21490910

  6. Water Absorption and HEMA Release of Resin-Modified Glass-Ionomers

    PubMed Central

    Beriat, Nilufer Celebi; Nalbant, Dilek

    2009-01-01

    Objectives The aim of this study was to evaluate the water absorption and the amount of hydroxyethyl metacrylate (HEMA) level released from various resin modified glass ionomer cements. Methods Advance, Vitremer and Protec-Cem resin modified glass ionomer cements were used to evaluate the HEMA release. Ten specimens were fabricated from each cement in 10 x 1 mm height. Thirty specimens were immersed in glass containers filled with 20 ml deionized water. 1 ml solution was taken from the container at 10 minutes, 1 hour, 24 hour and 7 days intervals from each group and analyzed with high performance liquid chromatography (HPLC) machine and the results are presented in ppm. The data were subjected to Kruskal-Wallis, Mann-Whitney and Wilcoxon tests at a 0.05 significance level. Results At all time intervals Vitremer showed highest HEMA release ( 10 min: 54.2 ppm; 1 h: 86.8 ppm; 24 h: 93.4 ppm) (P=0.0001). At the end of 10 minutes and first hour, following Vitremer, HEMA release was highest for Protec-Cem (10 min: 14.8 ppm; 1 h: 23.6 ppm) and then Advance (10 min: 5.5 ppm; 1 h: 18.8 ppm) (P<.05). Water absorption tests were performed according to the specifications of ISO 4049. Water absorption was highest for Vitremer and lowest for the Protec-Cem and the difference among cement groups was significant (P<.005). Conclusions Vitremer showed the highest HEMA release and water absorption values and Protec-Cem showed the lowest values. HEMA release by time was significant for Advance cement. This release may be relevant both to the risk of adverse pulpal responses in patients and to the risk of allergy in patients and dental personnel. PMID:19826597

  7. Nonaggregating Microspheres Containing Aldehyde Groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan

    1989-01-01

    Cobalt gamma irradiation of hydrophilic monomers in presence of acrolein yields exceptionally-stable, nonaggregating microspheres. Mixtures of 2-hydroxyethyl methacrylate (HEMA) and acrolein form homogeneous solutions in distilled water containing 0.4 percent polyethylene oxide (PEO). After deaeration with nitrogen, mixtures irradiated at room temperature with gamma rays from cobalt source; total exposure time 4 hours, at rate of 0.2 milliroentgen per hour. Reaction product centrifuged three times for purification and kept in distilled water.

  8. Optimization of urease immobilization onto non-porous HEMA incorporated poly(EGDMA) microbeads and estimation of kinetic parameters.

    PubMed

    Ayhan, F; Ayhan, H; Pişkin, E; Tanyolaç, A

    2002-01-01

    Jack bean urease (urea aminohydrolase, EC 3.5.1.5) was immobilized onto modified non-porous poly(ethylene glycol dimethacrylate/2-hydroxy ethylene methacrylate), (poly(EGDMA/HEMA)), microbeads prepared by suspension copolymerization for the potential use in hemoperfusion columns, not previously reported. The conditions of immobilization; enzyme concentration, medium pH, substrate and ethylene diamine tetra acetic acid (EDTA) presence in the immobilization medium in different concentrations, enzyme loading ratio, processing time and immobilization temperature were investigated for highest apparent activity. Immobilized enzyme retained 73% of its original activity for 75 days of repeated use with a deactivation constant kd = 3.72 x 10(-3) day(-1). A canned non-linear regression program was used to estimate the intrinsic kinetic parameters of immobilized enzyme with a low value of observable Thiele modulus (phi < 0.3) and these parameters were compared with those of free urease. The best-fit kinetic parameters of a Michaelis-Menten model were estimated as Vm = 3.318 x 10(-4) micromol/s mg bound enzyme protein, Km = 15.94 mM for immobilized, and Vm = 1.074 micromol NH3/s mg enzyme protein, Km = 14.49 mM for free urease. The drastic decrease in Vm value was attributed to steric effects, conformational changes in enzyme structure or denaturation of the enzyme during immobilization. Nevertheless, the change in Km value was insignificant for the unchanged affinity of the substrate with immobilization. For higher immobilized urease activity, smaller particle size and concentrated urease with higher specific activity could be used in the immobilization process.

  9. DFT studies of calcium(II), strontium(II) and barium(II) benzoates with N,N,N‧,N‧-Tetrakis(2-hydroxyethyl/propyl)ethylenediamine

    NASA Astrophysics Data System (ADS)

    Obrai, Sangeeta; Kumar, Rakesh; Goyal, Milli; Kaushal, Svati

    2016-06-01

    The computational study of some s-block metal nitrobenzoateate complexes: [Ca(THEEN)(H2O)]2+ (1), [Ca(THPEN)(H2O)2]2+ (2), [Sr(THPEN)(H2O)3]2+ (3), [Ba(THPEN)(H2O)2]22+(4), [Ba(THEEN)(H2O)2]22+ (5), (where THEEN (N,N,N‧,N'-Tetrakis(2-hydroxyethyl)ethylenediamine) and THPEN (N,N,N‧,N'- Tetrakis(2-hydroxypropyl)ethylenediamine) are tetrapodal ligands) is presented here using density functional theory (DFT) in its hybrid form B3LYP. The geometries of the title complexes are described by the quantum-chemical approach using input coordinates obtained from the previously synthesized and X-ray characterized diffraction data of [Ca(THEEN)(H2O)](DNB)2.H2O, [Ca(THPEN)(H2O)2](DNB)2.H2O [Sr(THPEN)(H2O)3](DNB)2, [Ba(THPEN)(H2O)2]2(DNB)4.2H2O and [Ba(THEEN)(H2O)2]2(ONB)4 (where DNB- is 3,5-dinitrobenzoate anion and ONB- is 2-nitrobenzoate). Only the primary coordination sphere of complexes (1) - (5) is optimized in the gaseous state. The calculation of energy gaps of frontier orbitals (HOMO-LUMO), 13C -NMR shifts and vibrational bands is carried out using B3LYP/6-31G**/LANL2DZ level of theory. The calculated geometric and spectral parameters reproduced the experimental data with well-agreement. HOMO-LUMO energy gap suggest that [Ca(THPEN)(H2O)2]2+ (2) is the most stable (HLG = 6.893 eV) among all the similar previously and presently reported complexes.

  10. Oxidative DNA damage induced by HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) buffer in the presence of Au(III).

    PubMed

    Habib, Ahsan; Tabata, Masaaki

    2004-11-01

    Oxidative DNA damage was investigated by free radicals generated from HEPES (2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid) buffer, which is widely used in biochemical or biological studies, in the presence of Au(III). The effect of free radicals on the DNA damage was ascertained by gel electrophoresis, electron spin resonance (ESR) spectroscopy and circular dichroism (CD) spectroscopy. ESR results indicated the generation of nitrogen-centered cationic free radicals from the HEPES in the presence of Au(III) which cause the DNA damage. No ESR spectra were observed for phosphate, tris(hydroxymethyl)aminomethane (Tris-HCl) and acetate buffers in the presence of Au(III) or for HEPES buffer in the presence of other metal ions such as Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) or [Au(III)(TMPyP)](5+) and [Pd(II)(TMPyP)](4+), where [H(2)(TMPyP)](4+) denotes tetrakis(1-methylpyridium-4-yl)porphyrin. Consequently, no DNA damage was observed for these buffer agents (e.g., phosphate, Tris-HCl or acetate) in the presence of Au(III) or for HEPES in the presence of other metal ions or the metalloporphyrins mentioned above. No detectable inhibitory effect on the DNA damage was observed by using the typical scavengers of reactive oxygen species (ROS) ()OH, O(2)(-) and H(2)O(2). This non-inhibitory effect indicated that no reactive oxygen species were generated during the incubation of DNA with HEPES and Au(III). The drastic change in CD spectra from positive ellipticity to negative ellipticity approximately at 270 nm with increasing concentration of Au(III) also indicated the significant damage of DNA. Only HEPES or Au(III) itself did not damage DNA. A mechanism for the damaging of DNA is proposed.

  11. Complexation of NpO2+ with (2-Hydroxyethyl)ethylenediaminetriacetic Acid (HEDTA) in Aqueous Solutions: Thermodynamic Studies and Structural Analysis

    SciTech Connect

    Li, Xingliang; Zhang, Zhicheng; Martin, Leigh R; Luo, Shunzhong; Rao, Linfeng

    2016-12-02

    Complexation of Np(V) with N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) was studied in aqueous solution (I = 1.0 mol L-1 NaClO4, t = 25 °C) by spectrophotometry, microcalorimetry and Extended X-ray absorption fine structure (EXAFS) spectroscopy. Equilibrium constants for the formation of three complexes, NpO2L2-, NpO2(HL)-, and (NpO2)2(OH)2L26-, were determined to be (6.91 ± 0.06), (4.28 ± 0.03) and -(4.93 ± 0.03), respectively. The enthalpies of complexation were determined to be -(8.0 ± 2.0) kJ mol-1 for NpO2L2- and -(2.2 ± 2.0) kJ mol-1 for NpO2(HL)-. Thermodynamic data of the complexation of Np(V) with HEDTA were compared to those of Np(V) with other aminopolycarboxylic acids, gaining insight into the possible coordination modes of the complexes. The EXAFS studies provided further structural information on those modes. In both NpO2L2- and NpO2(HL)- complexes, HEDTA coordinates to Np(V) in a tridentate mode through two oxygens of two carboxylic groups and one nitrogen of the amine group. In the (NpO2)2(OH)2L26- complex, two Np(V) atoms are bridged by two hydroxides and each HEDTA maintains the tridentate coordination mode.

  12. Perfluorooctanesulfonate (PFOS) Conversion from N-Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) in male Sprague Dawley rats after inhalation exposure.

    PubMed

    Chang, Sue; Mader, Brian T; Lindstrom, Kent R; Lange, Cleston C; Hart, Jill A; Kestner, Thomas A; Schulz, Jay F; Ehresman, David J; Butenhoff, John L

    2017-05-01

    Ethyl-N-(2-hydroxyethyl)-perfluorooctanesulfonamide (EtFOSE) was one of the key building blocks for many of the perfluorooctanesulfonyl-based chemistry and laboratory studies have shown that EtFOSE can metabolically degrade to perfluorooctanesulfonate (PFOS). Non-occupational contribution sources to PFOS are thought to occur in general population via diets, drinking water, air and dust. For workers, however, the exposure route was mostly airborne and the exposure source was predominantly to precursor compounds such as EtFOSE. We undertook this study to investigate how much EtFOSE was converted to PFOS in the serum for male rats after 6h of exposure to EtFOSE vapor (whole body) at ambient temperature, which simulated a work place exposure scenario. There were no abnormal clinical observations and all rats gained weight during study. Interim tail-vein blood samples, collected up to 21 days after exposure, were analyzed for Et-FOSE and PFOS concentrations by LC-MS/MS. Upon inhalation exposure, the biotransformation of EtFOSE to PFOS in serum in the male rats was rapid and very little EtFOSE was detected in the serum within 24h after EtFOSE exposure. The highest conversion to PFOS in serum after exposure to EtFOSE vapor appeared to occur between Day 8-14 post exposure. Considering the potential surface and fur adsorption of test compound in the whole-body exposure system, our data would support that at least 10% of the inhaled EtFOSE was biotransformed to PFOS in the serum based on the range of lower 95% CI (confidence interval) values. This information is valuable because it quantitatively translates EtFOSE exposure into serum PFOS concentration, which serves as a matrix for internal dosimetry (of PFOS exposure) that can be used as an anchor across species as well as between different exposure routes.

  13. DNA binding, DNA cleavage and HSA interaction of several metal complexes containing N-(2-hydroxyethyl)-N'-benzoylthiourea and 1,10-phenanthroline ligands.

    PubMed

    Peng, Bo; Gao, Zhuantao; Li, Xibo; Li, Tingting; Chen, Guorong; Zhou, Min; Zhang, Ji

    2016-10-01

    Four novel ternary metal complexes of the type [M(Phen)(L1)2)] [phen = 1,10-phenanthroline, L1 = N-(2-hydroxyethyl)-N'-benzoylthiourea, M = Ni(II)(1), Co(II) (2), Cu(II) (3), Pd(II) (4)] were synthesized. The organic ligands and their corresponding organometallic complexes have been characterized using UV-vis absorption spectroscopy, element analysis, infrared radiation spectroscopy and fluorescence spectra. DNA binding and cleavage studies of these complexes were conducted in detail. In vitro DNA-binding properties were studied by electronic absorption spectra and fluorescence spectra methods. The results indicate that all of the ternary metal complexes can efficiently bind to DNA via intercalation mode. The DNA-binding constants for all ternary compounds are around 4 × 10(6) M(-1). The binding propensity of the complexes to human serum albumin (HSA) was also investigated. Agarose gel electrophoresis study revealed that the metal complexes could cleave super-coiled pBR322 DNA to a nicked form in the absence of external agents. In vitro anti bacterial studies show that copper complex has weak antibacterial activities. Copper complex exhibits a better biological activity among all complexes. This study provides a new perspective and evaluation on the role and importance of the effect factors on the medicinal properties of benzoylthiourea compounds. Synchronous fluorescence spectra of HSA (10 μM) as a function of concentration of the complexes 1-4.

  14. Complexation of NpO2+ with (2-Hydroxyethyl)ethylenediaminetriacetic Acid (HEDTA) in Aqueous Solutions: Thermodynamic Studies and Structural Analysis

    DOE PAGES

    Li, Xingliang; Zhang, Zhicheng; Martin, Leigh R; ...

    2016-12-02

    Complexation of Np(V) with N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA) was studied in aqueous solution (I = 1.0 mol L-1 NaClO4, t = 25 °C) by spectrophotometry, microcalorimetry and Extended X-ray absorption fine structure (EXAFS) spectroscopy. Equilibrium constants for the formation of three complexes, NpO2L2-, NpO2(HL)-, and (NpO2)2(OH)2L26-, were determined to be (6.91 ± 0.06), (4.28 ± 0.03) and -(4.93 ± 0.03), respectively. The enthalpies of complexation were determined to be -(8.0 ± 2.0) kJ mol-1 for NpO2L2- and -(2.2 ± 2.0) kJ mol-1 for NpO2(HL)-. Thermodynamic data of the complexation of Np(V) with HEDTA were compared to those of Np(V) with othermore » aminopolycarboxylic acids, gaining insight into the possible coordination modes of the complexes. The EXAFS studies provided further structural information on those modes. In both NpO2L2- and NpO2(HL)- complexes, HEDTA coordinates to Np(V) in a tridentate mode through two oxygens of two carboxylic groups and one nitrogen of the amine group. In the (NpO2)2(OH)2L26- complex, two Np(V) atoms are bridged by two hydroxides and each HEDTA maintains the tridentate coordination mode.« less

  15. Solid-state dye laser based on Coumarin 540A-doped polymeric matrices

    NASA Astrophysics Data System (ADS)

    Costela, A.; Garcia-Moreno, I.; Figuera, J. M.; Amat-Guerri, F.; Barroso, J.; Sastre, R.

    1996-02-01

    Coumarin 540-A has been dissolved in a copolymer of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) 1:1 v/v and in a pure poly(methyl methacrylate) homopolymer (PMMA). Laser action has been induced in the resulting solid-state solutions pumped with 1.2 mJ pulses at 337 nm from a nitrogen laser. The effects on the laser performance of different polymerization methods, dye concentration and polymeric matrix composition have been evaluated. Energy conversion efficiencies of 11% and lifetimes of about 2000 pulses at 2 Hz repetition rate have been demonstrated.

  16. HemaSpot, a Novel Blood Storage Device for HIV-1 Drug Resistance Testing.

    PubMed

    Brooks, K; DeLong, A; Balamane, M; Schreier, L; Orido, M; Chepkenja, M; Kemboi, E; D'Antuono, M; Chan, P A; Emonyi, W; Diero, L; Coetzer, M; Kantor, R

    2016-01-01

    HemaSpot, a novel dried-blood storage filter device, was used for HIV-1 pol resistance testing in 30 fresh United States blood samples and 54 previously frozen Kenyan blood samples. Genotyping succeeded in 79% and 58% of samples, respectively, improved with shorter storage and higher viral load, and had good (86%) resistance mutation concordance to plasma.

  17. Improved performance of lithium ion battery separator enabled by co-electrospinnig polyimide/poly(vinylidene fluoride-co-hexafluoropropylene) and the incorporation of TiO2-(2-hydroxyethyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Chen, Weiya; Liu, Yanbo; Ma, Ying; Yang, Wenxiu

    2015-01-01

    Functionalized TiO2 (f-TiO2) was synthesized by the atom transfer radical polymerization process and then three types of composite nanofiber membranes including PI/PVdF-HFP (PI/PH, with no nanoparticles contained in PI), TiO2@PI/PVdF-HFP (T@PI/PH, with TiO2 mixed in PI) and f-TiO2@PI/PVdF-HFP (f-T@PI/PH, with f-TiO2 blended in PI) were prepared by bicomponent co-electrospinning technique which could separately maintain the original properties of both PVdF-HFP and PI nanofibers. UV-vis characterization manifested that the modified nanoparticles can provide significant improvements in reducing the particle agglomeration. Morphology, porosity, electrolyte uptake and liquid electrolyte contact angle of all the electrospun separators were investigated, and results showed that the composite separator with 2% f-TiO2 nanoparticle had smaller fiber diameter, higher porosity, larger electrolyte uptake, smaller contact angle and more excellent thermal dimensional stability. More importantly, the tensile strength of all the composite membranes increased by more than three times after thermal calendering process, which resulted from the several bonded points caused by the fusion of PVdF-HFP component with low melting temperature. Additionally, electrochemical properties of PI/PH, 2% T@PI/PH and 2% f-T@PI/PH composite separators and cycling performances of corresponding batteries were evaluated and 2% f-T@PI/PH composite separator showed better properties than the other two.

  18. Aggregation and transport of Brij surfactants in hydroxyethyl methacrylate hydrogels.

    PubMed

    Kapoor, Yash; Bengani, Lokendrakumar C; Tan, Grace; John, Vijay; Chauhan, Anuj

    2013-10-01

    Surfactant loaded polymeric hydrogels find applications in several technological areas including drug delivery. Drug transport can be attenuated in surfactant loaded gels through partitioning of the drug in the surfactant aggregates. The drug transport depends on the type of the aggregates and also on the surfactant transport because diffusion of the surfactant leads to dissolution of the aggregates. The drug and the surfactant transport can be characterized by the surfactant monomer diffusivity Ds. and the critical aggregation concentration C(*). Here we focus on the transport in hydroxyethyl methacrylate (HEMA) hydrogels loaded with three different types of Brij surfactants. We measure transport of a hydrophobic drug cyclosporine and the surfactant for surfactant loadings ranging from 0.1% to 8%, and utilize the data to predict the values of Ds. and C(*). We show that the predictions based on surfactant transport are significantly different from those based on modeling the drug transport. The differences are attributed to the assumption of just one type of aggregate in the gel irrespective of the total concentration. The transport data suggests existence of multiple types of aggregates and this hypothesis is validated for Brij 98 by imaging of the microstructure with free fracture SEM.

  19. Effect of temperature on the protonation of N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid in aqueous solutions: Potentiometric and calorimetric studies

    SciTech Connect

    Li, Xingliang; Zhang, Zhicheng; Endrizzi, Francesco; Martin, Leigh R.; Luo, Shunzhong; Rao, Linfeng

    2015-06-01

    The TALSPEAK process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Komplexes) has been demonstrated in several pilot-scale operations to be effective at separating trivalent actinides (An3+) from trivalent lanthanides (Ln3+). However, fundamental studies have revealed undesired aspects of TALSPEAK, such as the significant partitioning of Na+, lactic acid, and water into the organic phase, thermodynamically unpredictable pH dependence, and the slow extraction kinetics. In the modified TALSPEAK process, the combination of the aqueous holdback complexant HEDTA (N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid) with the extractant HEH[EHP] (2-ethyl(hexyl) phosphonic acid mono-2-ethylhexyl ester) in the organic phase has been found to exhibit a nearly flat pH dependence between 2.5 and 4.5 and more rapid phase transfer kinetics for the heavier lanthanides. To help understand the speciation of Ln3+ and An3+ in the modified TALSPEAK, systematic studies are underway on the thermodynamics of major reactions in the HEDTA system under conditions relevant to the process (e.g., higher temperatures). Thermodynamics of the protonation and complexation of HEDTA with Ln3+ were studied at variable temperatures. Equilibrium constants and enthalpies were determined by a combination of techniques including potentiometry and calorimetry. This paper presents the protonation constants of HEDTA at T = (25 to 70) °C. The potentiometric titrations have demonstrated that, stepwise, the first two protonation constants decrease and the third one slightly increases with the increase of temperature. This trend is in good agreement with the enthalpy of protonation directly determined by calorimetry. The results of NMR analysis further confirm that the first two protonation reactions occur on the diamine nitrogen atoms, while the third protonation reaction occurs on the oxygen of a

  20. Contribution of hydrophobic/hydrophilic modification on cationic chains of poly(ε-caprolactone)-graft-poly(dimethylamino ethylmethacrylate) amphiphilic co-polymer in gene delivery.

    PubMed

    Han, Shangcong; Wan, Haiying; Lin, Daoshu; Guo, Shutao; Dong, Hongxu; Zhang, Jianhua; Deng, Liandong; Liu, Ruming; Tang, Hua; Dong, Anjie

    2014-02-01

    Nanoparticles (NPs) assembled from amphiphilic polycations have been certified as potential carriers for gene delivery. Structural modification of polycation moieties may be an efficient route to further enhance gene delivery efficiency. In this study two electroneutral monomers with different hydrophobicities, 2-hydroxyethyl methacrylate (HEMA) and 2-hydroxyethyl acrylate (HEA), were incorporated into the cationic poly(dimethylamino ethyl methacrylate) (PDMAEMA) side-chains of amphiphilic poly(ε-caprolactone)-graft-poly(dimethylamino ethylmethacrylate) (PCD) by random co-polymerization, to obtain poly(ε-caprolactone)-graft-poly(dimethylamino ethyl methacrylate-co-2-hydroxyethyl methacrylate) (PCD-HEMA) and poly(ε-caprolactone)-graft-poly(dimethylamino ethyl methacrylate-co-2-hydroxyethyl acrylate) (PCD-HEA). Minimal HEA or HEMA moieties in PDMAEMA do not lead to statistically significant changes in particle size, zeta potential, DNA condensation properties and buffering capacity of the naked NPs. However, the incorporation of HEMA and HEA lead to reductions and increases, respectively, in the surface hydrophilicity of the naked NPs and NPs/DNA complexes, which was confirmed by water contact angle assay. These simple modifications of PDMAEMA with HEA and HEMA moieties significantly affect the gene transfection efficiency on HeLa cells in vitro: PCD-HEMA NP/DNA complexes show a much higher transfection efficiency than PCD NPs/DNA complexes, while PCD-HEA NPs/DNA complexes show a lower transfection efficiency than PCD NP/DNA complexes. Fluorescence activated cell sorter and confocal laser scanning microscope results indicate that the incorporation of hydrophobic HEMA moieties facilitates an enhancement in both cellular uptake and endosomal/lysosomal escape, leading to a higher transfection efficiency. Moreover, the process of endosomal/lysosomal escape confirmed in our research that PCD and its derivatives do not just rely on the proton sponge mechanism, but also

  1. Research on imidazo(1,2-a)benzimidazole derivatives. 22. Synthesis of 2,3-dihydroimidazo(1,2-a)benzimidazoles starting from 2-imino-3-(2-hydroxyethyl)benzimidazolines

    SciTech Connect

    Anisimova, V.A.; Levchenko, M.V.; Pozharskii, A.F.

    1987-01-01

    A US -elimination reaction with the formation of 2-imino-3-vinylbenzimidazolines occurs simultaneously with intramolecular alkylation and the formation of an imidazoline ring in the action of alcoholic alkali on 2-imino-3-(2-chloroethyl)benzimidazolines. The thermolysis of 3-chloroethyl-substituted imines without a solvent or in an inert solvent leads exclusively to 2,3-dihydroimidazo(1,2-a)benzimidazoles. An attempt to obtain the latter directly from 2-imino-3-(2-hydroxyethyl)benzimidazolines by the action of a mixture of thionyl chloride and acetic anhydride on them also leads to ambiguous results.

  2. Influence of metallic silver nanoparticles on photo-physical properties of pyrromethene PM567 laser dye in liquid and solid hosts

    NASA Astrophysics Data System (ADS)

    Gadallah, A.-S.; Alhijry, Ibraheem A.; Abdelkader, H. I.; Abou Kana, Maram T. H.

    2015-11-01

    The influence of [Ag NPs: PM567] complex formation on optical properties of parent PM567 laser dye in 2-hydroxyethyl methacrylate (homomonomer, homopolymer) and 2-hydroxyethyl methacrylate/methyl methacrylate (comonomer, copolymer) hosts was studied at room temperature. The silver nanoparticles were synthesized by chemical reduction method. Its size and concentration was determined by high resolution transmission electron microscope and UV/VIS absorption spectroscopy. The experimental results showed that the optical properties of dye were remarkably enhanced with optimum concentrations of NPs and dye. The effect of different nanoparticle concentrations on the optical properties of complex based not only on NPs and dye concentrations, but also on nature of milieu. Whereas, [1×10-4 mol/L PM567:40% C Ag NPs] and [1×10-3 mol/L PM567:40% C Ag NPs] were the optimum complexes in case of monomer and polymer hosts respectively. Also, at optimum concentration of PM567 dye in polymeric samples (1×10-3 mol/L), the gain values of dye in HEMA were 1.9 and 2.4 with respect to absence and presence of Ag NPs. While in HEMA/MMA copolymer, the gain values were 1.8 and 2.45 respectively. In a deeper study, [1×10-3 mol/L: 40% C Ag NPs] complex in HEMA/MMA copolymer host had preferable ASE Slope efficiencies and photostabilities, compared with complex in HEMA homopolymer host.

  3. Effect of mouse VEGF164 on the viability of hydroxyethyl methacrylate-methyl methacrylate-microencapsulated cells in vivo: bioluminescence imaging.

    PubMed

    Cheng, Dangxiao; Lo, Chuen; Sefton, Michael V

    2008-11-01

    Bioluminescent imaging was used to track the viability of luciferase transfected L929 cells in poly(hydroxyethyl methacrylate-co-methyl methacrylate) (HEMA-MMA) microcapsules. Bioluminescence, as determined by Xenogen imaging after addition of luciferin to microcapsules in vitro, increased with time, consistent with an increase in cell number. Capsules were suspended in Matrigel and injected subcutaneously. The bioluminesence in vivo increased over the first 3 weeks and then decreased, both with and without the delivery of mVEGF(164) (1.2 ng/24 h/200 microcapsules in vitro); VEGF delivery was from microencapsulated doubly transfected cells (both luciferase and mVEGF(164)). VEGF delivery was sufficient to generate a greater number of vascular structures, but this did not result in the expected increase in microencapsulated cell viability. Interestingly, the number of vessels at day 28 was less than at day 21, consistent with what would be an expected reduction in VEGF secretion when cell viability is lost. The results presented here do not support the hypothesis that transfection of microencapsulated cells with VEGF is sufficient to correct the oxygen transport limitation, at least with this type of tissue engineering construct. On the other hand, bioluminescent imaging proved to be a useful method of monitoring microencapsulated cell viability over many weeks in vivo.

  4. Polymerization shrinkage and stress development in amorphous calcium phosphate/urethane dimethacrylate polymeric composites

    PubMed Central

    Antonucci, J.M.; Regnault, W. F.; Skrtic, D.

    2010-01-01

    This study explores how substituting a new high molecular mass oligomeric poly(ethylene glycol) extended urethane dimethacrylate (PEG-U) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated urethane dimethacrylate (UDMA) resins affects degree of vinyl conversion (DC), polymerization shrinkage (PS), stress development (PSSD) and biaxial flexure strength (BFS) of their amorphous calcium phosphate (ACP) composites. The composites were prepared from four types of resins (UDMA, PEG-U, UDMA/HEMA and UDMA/PEG-U) and zirconia-hybridized ACP. Introducing PEG-U improved DC while not adversely affecting PS, PSSD and the BFS of composites. This improvement in DC is attributed to the long, more flexible structure between the vinyl groups of PEG-U and its higher molecular mass compared to poly(HEMA). The results imply that PEG-U has the potential to serve as an alternative to HEMA in dental and other biomedical applications. PMID:20169007

  5. Reduced lymphocyte activation in space: Role of cell-substratum interactions

    NASA Technical Reports Server (NTRS)

    Gmuender, Felix K.; Kiess, M.; Sonnenfeld, Gerald; Lee, J.; Cogoli, Augusto

    1990-01-01

    The effect of substratum adhesiveness on lymphocyte responsiveness was investigated by reducing and blocking cell adhesion with poly-HEMA (poly (2-Hydroxyethyl Methacrylate)) in a simple on ground system. Cells grown on medium thick and thick poly-HEMA films were rounded in shape and displayed no signs of spreading. By contrast, on tissue culture plastic and very thin poly-HEMA films, they showed clear signs of spreading. The mitogenic response of lymphocytes grown on thick poly-HEMA films was reduced by up to 68 percent of the control (tissue culture plastic). Interferon gamma production was virtually nil when the cells were grown on the least adhesive substratum. These results show that activated lymphocytes need to anchor and spread prior to achieving an optimal proliferation response. It is concluded that decreased lymphocyte adhesion could contribute to the depressed in vitro lymphocyte responsiveness found in the microgravity conditions of space flight.

  6. Expression of the Rhodobacter sphaeroides hemA and hemT genes, encoding two 5-aminolevulinic acid synthase isozymes.

    PubMed Central

    Neidle, E L; Kaplan, S

    1993-01-01

    The nucleotide sequences of the Rhodobacter sphaeroides hemA and hemT genes, encoding 5-aminolevulinic acid (ALA) synthase isozymes, were determined. ALA synthase catalyzes the condensation of glycine and succinyl coenzyme A, the first and rate-limiting step in tetrapyrrole biosynthesis. The hemA and hemT structural gene sequences were 65% identical to each other, and the deduced HemA and HemT polypeptide sequences were 53% identical, with an additional 16% of aligned amino acids being similar. HemA and HemT were homologous to all characterized ALA synthases, including two human ALA synthase isozymes. In addition, they were evolutionarily related to 7-keto-8-aminopelargonic acid synthetase (BioF) and 2-amino-3-ketobutyrate coenzyme A ligase (Kbl), enzymes which catalyze similar reactions. Two hemA transcripts were identified, both expressed under photosynthetic conditions at levels approximately three times higher than those found under aerobic conditions. A single transcriptional start point was identified for both transcripts, and a consensus sequence at this location indicated that an Fnr-like protein may be involved in the transcriptional regulation of hemA. Transcription of hemT was not detected in wild-type cells under the physiological growth conditions tested. In a mutant strain in which the hemA gene had been inactivated, however, hemT was expressed. In this mutant, hemT transcripts were characterized by Northern (RNA) hybridization, primer extension, and ribonuclease protection techniques. A small open reading frame of unknown function was identified upstream of, and transcribed in the same direction as, hemA. Images PMID:8468290

  7. Lysozyme immobilization onto PVC catheters grafted with NVCL and HEMA for reduction of bacterial adhesion

    NASA Astrophysics Data System (ADS)

    Guadarrama-Zempoalteca, Yesica; Díaz-Gómez, Luis; Meléndez-Ortiz, H. Iván; Concheiro, Angel; Alvarez-Lorenzo, Carmen; Bucio, Emilio

    2016-09-01

    The aim of the present work was to functionalize poly(vinyl chloride) (PVC) urinary catheters with grafted copolymers that can improve the biocompatibility and serve as binding points of lysozyme. PVC catheters were modified by grafting a mixture of N-vinylcaprolactam (NVCL) and 2-hydroxyethylmethacrylate (HEMA) applying a gamma-ray pre-irradiation method. The effect of absorbed dose, monomer concentration, temperature, and reaction time on the grafting percentage was evaluated. The grafted catheters were characterized regarding surface composition (FTIR-ATR spectroscopy), thermal properties (DSC and TGA) and swelling in aqueous medium. Lysozyme was directly coupled onto PVC-g-(NVCL/HEMA) previously activated using carbonyldiimidazole. Antimicrobial lytic activity of the modified catheters over time was tested against Micrococcus lysodeikticus. Lysozyme diminished the adhesion of Staphylococcus aureus onto the functionalized catheters, which may be suitable to prevent biofilm formation.

  8. Ocular Drug Delivery through pHEMA-Hydrogel Contact Lenses Co-Loaded with Lipophilic Vitamins

    PubMed Central

    Lee, Dasom; Cho, Seungkwon; Park, Hwa Sung; Kwon, Inchan

    2016-01-01

    Ocular drug delivery through hydrogel contact lenses has great potential for the treatment of ocular diseases. Previous studies showed that the loading of lipophilic vitamin E to silicone-hydrogel contact lenses was beneficial in ocular drug delivery. We hypothesized that vitamin E loading to another type of popular hydrogel contact lenses, pHEMA-hydrogel contact lenses, improves ocular drug delivery by increasing the drug loading or the duration of drug release. Loading of vitamin E to pHEMA-hydrogel contact lenses significantly increased the loading of a hydrophilic drug surrogate (Alexa Fluor 488 dye) and two hydrophilic glaucoma drugs (timolol and brimonidine) to the lenses by 37.5%, 19.1%, and 18.7%, respectively. However, the release duration time was not significantly altered. Next, we hypothesized that the lipophilic nature of vitamin E attributes to the enhanced drug loading. Therefore, we investigated the effects of co-loading of another lipophilic vitamin, vitamin A, on drug surrogate delivery. We found out that vitamin A loading also increased the loading of the drug surrogate to pHEMA-hydrogel contact lenses by 30.3%. Similar to vitamin E loading, vitamin A loading did not significantly alter the release duration time of the drug or drug surrogate. PMID:27678247

  9. Ocular Drug Delivery through pHEMA-Hydrogel Contact Lenses Co-Loaded with Lipophilic Vitamins

    NASA Astrophysics Data System (ADS)

    Lee, Dasom; Cho, Seungkwon; Park, Hwa Sung; Kwon, Inchan

    2016-09-01

    Ocular drug delivery through hydrogel contact lenses has great potential for the treatment of ocular diseases. Previous studies showed that the loading of lipophilic vitamin E to silicone-hydrogel contact lenses was beneficial in ocular drug delivery. We hypothesized that vitamin E loading to another type of popular hydrogel contact lenses, pHEMA-hydrogel contact lenses, improves ocular drug delivery by increasing the drug loading or the duration of drug release. Loading of vitamin E to pHEMA-hydrogel contact lenses significantly increased the loading of a hydrophilic drug surrogate (Alexa Fluor 488 dye) and two hydrophilic glaucoma drugs (timolol and brimonidine) to the lenses by 37.5%, 19.1%, and 18.7%, respectively. However, the release duration time was not significantly altered. Next, we hypothesized that the lipophilic nature of vitamin E attributes to the enhanced drug loading. Therefore, we investigated the effects of co-loading of another lipophilic vitamin, vitamin A, on drug surrogate delivery. We found out that vitamin A loading also increased the loading of the drug surrogate to pHEMA-hydrogel contact lenses by 30.3%. Similar to vitamin E loading, vitamin A loading did not significantly alter the release duration time of the drug or drug surrogate.

  10. Extended wear therapeutic contact lens fabricated from timolol imprinted carboxymethyl chitosan-g-hydroxy ethyl methacrylate-g-poly acrylamide as a onetime medication for glaucoma.

    PubMed

    Anirudhan, T S; Nair, Anoop S; Parvathy, J

    2016-12-01

    An extended wear therapeutic contact lens (TCL) for the sustained delivery of timolol maleate (TML) was fabricated based on molecular imprinting technique. The designed TCL comprised of a TML imprinted copolymer of carboxymethyl chitosan-g-hydroxy ethyl methacrylate-g-polyacrylamide (CmCS-g-HEMA-g-pAAm) embedded onto a poly HEMA matrix (pHEMA). Successful reloading of TML onto the lens was monitored using a simple and novel UV-Visible spectrophotometric method which showed an excellent reloading capacity of 6.53μgTML/TCL. The in vitro drug release profile in lacrimal fluid after each cycle was fitted onto Higuchi model of drug release suggesting diffusion release mechanism with no polymer degradation. Also, the TML release kinetics indicated a sustained drug delivery which can effectively achieve the therapeutic index of TML leading to a onetime medication for glaucoma. Biological activity of eluted drug after each cycle and cell viability of the TCL were verified using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,3-bis(2-methoxynitro-5-sulfophenyl)-5-(phenylaminocarbonyl)-2H-tetrazolium hydroxide (XTT) assay, respectively.

  11. Adsorption of proteins from artificial tear solutions to contact lens materials

    SciTech Connect

    Bohnert, J.L.; Horbett, T.A.; Ratner, B.D.; Royce, F.H.

    1988-03-01

    A series of polymers and copolymers of 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) were synthesized in order to find surfaces that would adsorb minimal amounts of protein. The adsorption of albumin, lysozyme and immunoglobulin G from a three-way mixture of these proteins in isotonic buffered saline to the polymers was measured using /sup 125/I-labeled proteins. Apparently high protein uptake on copolymers rich in HEMA was found to be due to sorption of unbound /sup 125/I by the polymers. /sup 125/I sorption by the polymers was minimized by dialysis of the protein solution to remove unbound /sup 125/I iodide and inclusion of 0.01 M sodium iodide to block uptake of residual /sup 125/I iodide. Using these improved protocols, minimal total protein uptake was observed on copolymers containing 50% or more HEMA. The majority of adsorbed protein on all p(MMA-HEMA) polymers was albumin. Total protein uptake was greatest on pMMA. Commercial contact lenses composed of copolymers of HEMA and N-vinyl pyrrolidone (NVP) or acrylamide (AAm) adsorbed small amounts of all proteins whereas copolymers of methacrylic acid (MAAc) and HEMA adsorbed much larger quantities of lysozyme. These results indicate that protein uptake by contact lens materials varies greatly with polymer composition. Artifactually high adsorption can occur if precautions are not taken to prevent uptake of unbound /sup 125/I.

  12. 78 FR 55644 - Styrene, Copolymers with Acrylic Acid and/or Methacrylic Acid; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... methacrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and/or hydroxyethyl acrylate; and its sodium... methacrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and/or hydroxyethyl acrylate; and its sodium... methacrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and/or hydroxyethyl acrylate, and its...

  13. Radiolabeling of new generation magnetic poly(HEMA-MAPA) nanoparticles with (131) I and preliminary investigation of its radiopharmaceutical potential using albino Wistar rats.

    PubMed

    Avcıbaşı, Uğur; Demiroğlu, Hasan; Ediz, Melis; Akalın, Hilmi Arkut; Özçalışkan, Emir; Şenay, Hilal; Türkcan, Ceren; Özcan, Yeşim; Akgöl, Sinan; Avcıbaşı, Nesibe

    2013-12-01

    In this study, N-methacryloyl-l-phenylalanine (MAPA) containing poly(2-hydroxyethylmethacrylate) (HEMA)-based magnetic poly(HEMA-MAPA) nanobeads [mag-poly(HEMA-MAPA)] were radiolabeled with (131) I [(131) I-mag-poly(HEMA-MAPA)], and the radiopharmaceutical potential of (131) I-mag-poly(HEMA-MAPA) was investigated. Quality control studies were carried out by radiochromatographic method to be sure that (131) I binded to mag-poly(HEMA-MAPA) efficiently. In this sense, binding yield of (131) I-mag-poly(HEMA-MAPA) was found to be about 95-100%. In addition to this, optimum radiodination conditions for (131) I-mag-poly(HEMA-MAPA) were determined by thin-layer radiochromatography studies. In addition to thin-layer radiochromatography studies, lipophilicity (partition coefficient) and stability studies for (131) I-mag-poly(HEMA-MAPA) were realized. It was determined that lipophilicities of mag-poly(HEMA-MAPA) and (131) I-mag-poly(HEMA-MAPA) were 0.12 ± 0.01 and 1.79 ± 0.76 according to ACD/logP algorithm program, respectively. Stability of the radiolabeled compound was investigated in time intervals given as 0, 30, 60, 180, and 1440 min. It was found that (131) I-mag-poly(HEMA-MAPA) existed as a stable complex in rat serum within 60 min. After that, biodistribution and scintigraphy studies were carried out by using albino Wistar rats. It was determined that the most important (131) I activity uptake was observed in the breast, the ovary, and the pancreas. Scintigraphy studies well supported biodistribution results.

  14. Polyelectrolyte hydrogel instabilities in ionic solutions

    NASA Astrophysics Data System (ADS)

    English, Anthony E.; Tanaka, Toyoichi; Edelman, Elazer R.

    1996-12-01

    The phase behavior of polyelectrolyte hydrogels has been examined as a function of relative charge composition, bath salt concentration, and solvent quality. Nonlinear swelling instabilities of 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAAc) copolymer hydrogels manifested themselves as discontinuous first order swelling transitions as a function of bath salt concentration. A modified Flory-Huggins model was used to describe the regions of instability when bath salt concentration and solvent quality are considered as control variables. The role of ion dissociation equilibrium in the change from local or smooth transitions to nonlocal or discontinuous swelling transitions is illustrated within the framework of our model.

  15. Adhesion of Escherichia coli on to a series of poly(methacrylates) differing in charge and hydrophobicity.

    PubMed

    Harkes, G; Feijen, J; Dankert, J

    1991-11-01

    The adhesion of three Escherichia coli strains on to six poly(methacrylates) differing in hydrophobicity and surface charge was measured as a function of time under laminar flow conditions. Polymers used were poly(methyl methacrylate) (PMMA), poly(hydroxyethyl methacrylate) (PHEMA) and copolymers of MMA or HEMA with either 15% methacrylic acid (MAA) or 15% trimethylaminoethyl methacrylate-HCl salt (TMAEMA-Cl). Bacterial and polymer surfaces were characterized by means of water contact angles and zeta potentials. Both the sessile drop contact angles and the zeta potentials of the bacterial surfaces were significantly different. No significant differences in the sessile drop contact angles of the polymer surfaces were observed. Using the Wilhelmy plate technique large contact angle hysteresis was observed for the different polymer surfaces. Surfaces of copolymers with MAA had more negative zeta potentials than those of the corresponding homopolymers. Surfaces of copolymers with TMAEMA-Cl had positive zeta potentials. The highest numbers of adherent bacteria were found on materials with positive zeta potentials, irrespective of the bacterial strain used. Bacterial adhesion on to copolymers with MAA was less than on to the corresponding homopolymers. Bacterial equilibrium adhesion values correlate with the zeta potentials of the polymer surfaces (r greater than 0.85). On substrates with less negative zeta potentials high numbers of adhered bacteria were observed. Additionally, the equilibrium bacterial adhesion values could be related with receding contact angles of polymer surfaces with negative zeta potentials (r greater than 0.86). High equilibrium adhesion values were obtained for polymers with high contact angles. No correlation between the zeta potentials and contact angles of the bacteria with the adhesion values was found.

  16. Poly(2-hydroxy ethyl methacrylate)-alkaline phosphatase: a composite biomaterial allowing in vitro studies of bisphosphonates on the mineralization process.

    PubMed

    Filmon, R; Baslé, M F; Barbier, A; Chappard, D

    2000-01-01

    We have immobilized the mineralizing agent alkaline phosphatase (AlkP) in a hydrophilic polymer: poly(2-hydroxy ethyl methacrylate) - (pHEMA) - in a copolymerization technique. Histochemical study on polymer sections revealed that AlkP has retained its enzymic activity. The image analysis of sections using a tessellation method showed a lognormal distribution of the area of the tiles surrounding AlkP particles, thus confirming a homogeneous distribution of the enzyme in the polymer. Pellets of pHEMA-AlkP were incubated with a synthetic body fluid containing organic phosphates (beta-glycerophosphate). Mineral deposits with a rounded shape (calcospherites) were obtained in about 17 days. We have investigated the effects of three bisphosphonic pharmacological compounds (etidronate, alendronate and tiludronate) on this system which mimics the mineralization process of cartilage and woven bone. Bisphosphonates at a concentration of 10(-2) M totally inhibited AlkP in solution at a concentration of 10(-4) mg/ml. Inhibition has been reported being due to the chelation of a metal cofactor (Zn2+). Etidronate and alendronate appeared to similarly inhibit the calcospherite deposition onto the pHEMA-AlkP material. Both bisphosphonates possess three sites for the mineral complexion by Ca chemisorbtion. On the other hand, tiludronate having only two sites, was associated with a reduced inhibitory effect on mineralization but larger crystals were obtained. The pHEMA-AlkP material contains an immobilized enzyme in a hydrogel and mimics the physiological conditions of matrix vesicles entrapped within the cartilage (or bone) matrix. It provides an interesting method to study the effects of pharmacological compounds on the mineralization process in bone and cartilage in a non cellular and protein-free model.

  17. The Pseudomonas aeruginosa hemA promoter is regulated by Anr, Dnr, NarL and Integration Host Factor.

    PubMed

    Krieger, R; Rompf, A; Schobert, M; Jahn, D

    2002-05-01

    Pseudomonas aeruginosa forms most of its heme under anaerobic denitrifying conditions. To study the regulation of the hemA gene, which codes for the first enzyme of heme biosynthesis in P. aeruginosa, a lacZ reporter gene fusion was constructed. Expression of lacZ under the control of the hemA promoter was found to be increased by 2.8-fold under anaerobic conditions in the presence of the alternative electron acceptor nitrate, relative to the level observed under aerobic growth conditions. Anaerobic fermentative growth or the presence of nitrite did not affect the lacZ expression. The genes encoding the oxygen sensor protein Anr, the redox regulator Dnr, the nitrate regulator NarL and the DNA-bending Integration Host Factor (IHF) are all required for the cooperative anaerobic induction of the hemA promoter hemAp (1). Potential binding sites for these regulatory proteins were identified by site-directed mutagenesis of the promoter fused to the reporter gene. The mode of regulation of P. aeruginosa hemA differs significantly from that described for the hemA gene of Escherichia coli K-12.

  18. Biocompatibility investigation and urea removal from blood by urease-immobilized HEMA incorporated poly(ethyleneglycol dimethacrylate) microbeads.

    PubMed

    Ayhan, F; Yousefi Rad, A; Ayhan, H

    2003-01-15

    The biocompatibility of modified and urease-immobilized poly(ethyleneglycol dimethacrylate/2-hydroxyethylmetacrylate) [poly(EGDMA/HEMA)] microbeads was tested through blood compatibility tests. Twelve percent HEMA incorporated nonporous particles of 105-125 microm were used in the research. Hydroxyl groups on microbeads were chemically modified by following a three-step procedure that is composed of activation, spacer-arm incorporation (hexamethylene diamine) and, finally, glutaraldehyde bounding. Enzyme urease was immobilized on microbead surfaces, and adsorption of blood proteins in serum and plasma, blood coagulation time, and leukocyte and platelet adhesion were tested. Incubation of 1.5 cc of biological fluid with 100 mg of urease-immobilized poly(EGDMA/HEMA) microbeads at room temperature shows that protein adsorption on surfaces occurs, but protein content after treatment was in the range of healthy people. Adsorbed albumin and total globulin amounts per gram of microbeads is much greater than fibrinogen. Immobilization of urease reduced the protein adsorption and blood coagulation times compared with those of modified microbeads. Prothrombin time (PT) was not altered much, whereas poly(EGDMA/HEMA) microbeads induced a significant increase of activated partial thromboplastin time (APTT). The platelet and leukocyte adhesion slightly increased with the modification of poly(EGDMA/HEMA) and decreased with the introduction of urease. When blood samples were treated with urease-immobilized microbeads, BUN values of patients were lowered to almost acceptable amounts.

  19. Identification of the enzymatic basis for. delta. -aminolevulinic acid auxotrophy in a hemA mutant of escherichia coli

    SciTech Connect

    Avissar, Y.J.; Beale, S.I. )

    1989-06-01

    The hemA mutation of Escherichia coli K-12 confers a requirement for {delta}-aminolevulinic acid (ALA). Cell extract prepared from the hemA strain SASX41B was incapable of producing ALA from either glutamate or glutamyl-tRNA, whereas extract of the hem{sup +} strain HB101 formed colorimetrically detectable amounts of ALA and transferred label from 1-({sup 14}C)glutamate and 3,4-({sup 3}H)glutamyl-tRNA to ALA. Extracts of both strains converted glutamate-1-semialdehyde to ALA and were capable of aminoacylating tRNA{sup Glu}. Glutamyl-tRNA formed by extracts of both strains could be converted to ALA by the extract of hem{sup +} cells. The extract of hemA cells did not convert glutamyl-tRNA formed by either strain to ALA. However, the hemA cell extract, when supplemented in vitro with glutamyl-tRNA dehydrogenase isolated from Chlorella vulgaris cells, formed about as much ALA as did the unsupplemented hem{sup +} cell extract. We conclude from these observations that the enzyme activity that is lacking in the ALA auxotrophic strain carrying the hemA mutation is that of glutamyl-tRNA dehydrogenase.

  20. The morphological and biomechanical changes of keratocytes cultured on modified p (HEMA-MMA) hydrogel studied by AFM.

    PubMed

    Yan, Tuo; Sun, Rong; Deng, Hua; Tan, Baihua; Ao, Ningjian

    2009-01-01

    The poor integration with host cornea tissue and the low mechanical properties of pHEMA hydrogel for artificial cornea remains a difficult problem to solve. A modified pHEMA hydrogel, MMA copolymerized and type-I collagen and bFGF immobilized, was previously prepared in an attempt to solve the problems. In this study, the cytotoxicity of Col/bFGF-p (HEMA-MMA) and p (HEMA-MMA) was studied by cell adhesion assay and atomic force microscopy (AFM). The results of cell adhesion assay show that the attachment of keratocytes on the modified membrane is much higher than that of the unmodified membrane. This indicates that the material after modification have better cell-material interaction. The AFM images reveal that the morphology of keratocytes cultured on different substrate is obviously different. The cell cultured on modified membrane presented a completely elongated and spindle-shape morphology. The force-distance indicates that the biomechanical of keratocytes changes significantly after culturing on different substrates. The adhesion force (2328+/-523 pN) and Young's modulus (0.51+/-0.125 kPa) of the cell cultured on modified membrane are much higher, and the stiffness (0.08+/-0.022 mN/m) is lower than those of the cell cultured on unmodified membrane. These results show that the cytotoxicity of Col/bFGF-p (HEMA-MMA) for keratocytes is much improved.

  1. Thermomechanical behavior of amorphous tactic methacrylate polymers

    NASA Technical Reports Server (NTRS)

    Kiran, E.; Gillham, J. K.; Gipstein, E.

    1974-01-01

    Dynamic mechanical spectra of amorphous stereoregular poly(methyl methacrylate)s and poly(t-butyl methacrylate)s with assigned microtacticities are presented and discussed. An intermolecular argument is invoked to account for the higher glass transition temperature of syndiotactic vis a vis isotactic PMMA, in spite of the higher density of the latter at 30 C. An argument is presented to show that the ratio of glassy-region relaxation temperature to glass transition temperature is not only a measure of the degree of coupling of the beta and glass transition processes, but also of the degree to which intermolecular factors influence these processes. The greater extent of the low-temperature irreversibilities observed in the thermomechanical spectra of poly(t-butyl methacrylate)s is attributed to the brittle character induced by the bulky side groups which presumably weaken cohesive forces.

  2. About the effect of eye blinking on drug release from pHEMA-based hydrogels: an in vitro study.

    PubMed

    Galante, R; Paradiso, P; Moutinho, M G; Fernandes, A I; Mata, J L G; Matos, A P A; Colaço, R; Saramago, B; Serro, A P

    2015-01-01

    The development of new ophthalmic drug delivery systems capable of increasing the residence time of drugs in the eye and improve its bioavailability relatively to eyedrops has been object of intense research in recent years. Several studies have shown that drug-loaded therapeutic soft contact lenses (SCLs) constitute a promising approach, with several potential advantages as compared with collyria. The main objective of this work is to study the effect of repetitive load and friction cycles caused by the eye blinking, on the drug release from hydrogels used in SCLs which, as far as we know, was never investigated before. Two poly-2-hydroxyethylmethacrylate-based hydrogels, pHEMA-T and pHEMA-UV, were used as model materials. Levofloxaxin was chosen as model drug. The hydrogels were fully characterized in what concerns structural and physicochemical properties. pHEMA-UV revealed some superficial porosity and a lower short-range order than pHEMA-T. We observe that the load and friction cycles enhanced the drug release from pHEMA-UV hydrogels. The application of a simple mathematical model, which takes into account the drug dilution caused by the tear flow, showed that the enhancement of the drug release caused by blinking on this hydrogel may be relevant in in vivo conditions. Conversely, the more sustained drug release from pHEMA-T is not affected by load and friction cycles. The conclusion is that, depending on the physicochemical and microstructural characteristics of the hydrogels, blinking is a factor that may affect the amount of drug delivered to the eye by SCLs and should thus be considered.

  3. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate... generically as polymers of styrene, cyclohexyl methacrylate and substituted methacrylate (PMNs...

  4. Incorporation of polymerizable surfactants in hydroxyethyl methacrylate lenses for improving wettability and lubricity.

    PubMed

    Bengani, Lokendrakumar C; Scheiffele, Gary W; Chauhan, Anuj

    2015-05-01

    Dryness and discomfort are the main reasons for dropouts in contact lens wearers. Incorporating surfactants in lens formulations could improve wettability and lubricity, which can improve comfort. We have focused on incorporating polymerizable surfactants in hydroxyethyl methacrylate lenses to improve comfort, while minimizing the potential for surfactant release into the tears. The surfactants were added to the polymerization mixture, followed by UV curing and extraction of leachables in hot water. Wettability and lubricity were characterized by measuring the contact angle and coefficient of friction. Lenses were also characterized by measuring transmittance, loss and storage moduli and ion permeability. Incorporation of surfactants significantly reduced contact angle from 90° for p-HEMA gels to about 10° for 2.43% (w/w) surfactant loading in hydrated gel. The coefficient of friction also decreased from about 0.16 for HEMA gels to 0.05 for the gels with 2.43% surfactant loading. There was a good correlation between the contact angle and coefficient of friction suggesting that both effects can be related to the stretching of the surfactant tails near the surface into the aqueous phase. The water content was also correlated with the surfactant loading but the contact angle was more sensitive suggesting that the observed improvements in wettability and lubricity arise from the protrusion of the surfactant tails in into the liquid, and not purely from the increase in the water content. The gels were clear and certain compositions also have the capability to block UVC and UVB radiation. The results suggest that incorporation of polymerizable surfactants could be useful in improving surface properties without significantly impacting any bulk property.

  5. Effect of heavy ion irradiation on optical property of radiation-crosslinked hydroxypropyl cellulose gel containing methacrylate monomers

    NASA Astrophysics Data System (ADS)

    Hiroki, A.; Yamashita, S.; Kimura, A.; Nagasawa, N.; Taguchi, M.

    2015-12-01

    Effects of dose rate and liner energy transfer (LET) on the optical property of a polymer gel dosimeter irradiated with swift heavy ions were investigated. The polymer gel dosimeters that consist of 2-hydroxyethyl methacrylate, polyethylene glycol dimethacrylate, and tetrakis(hydroxymethyl)phosphonium chloride with radiation-crosslinked hydroxypropyl cellulose gel matrix were prepared. The dosimeters were irradiated with 150 MeV/u He ions, 290 MeV/u C ions, and 500 MeV/u Fe ions at HIMAC, and then were optically analyzed by using a UV-Vis spectrophotometer. Absorbance of the irradiated dosimeters increased with an increase in the dose up to 10 Gy. The absorbance at the dose of 5 Gy decreased with increasing dose rate in all of the heavy ions. The dosimeter irradiated with Fe ions exhibited the lowest dose response of the absorbance. It was found that the sensitivity of the dosimeters decreased with increasing dose rate as well as LET of the incident heavy ions.

  6. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may... produced by the polymerization of methacrylic acid and divinylbenzene. The divinylbenzene functions as...

  7. Separation of PCR-ready DNA from dairy products using magnetic hydrophilic microspheres and poly(ethylene glycol)-NaCl water solutions

    NASA Astrophysics Data System (ADS)

    Rittich, Bohuslav; Španová, Alena; Šálek, Petr; Němcová, Petra; Trachtová, Štěpánka; Horák, Daniel

    2009-05-01

    Carboxyl group-containing magnetic nonporous poly(2-hydroxyethyl methacrylate- co-glycidyl methacrylate) (P(HEMA- co-GMA)) and magnetic glass microspheres were used for the isolation of bacterial DNA. P(HEMA- co-GMA) microspheres were prepared by the dispersion polymerization in toluene/2-methylpropan-1-ol mixture in the presence of magnetite nanoparticles obtained by coprecipitation of Fe(II) and Fe(III) salts with ammonium hydroxide. Carboxyl groups were then introduced by oxidation of the microspheres with potassium permanganate. The most extensive DNA recovery was achieved at PEG 6000 concentrations of 12% or 16% and 2 M NaCl. The method proposed was used for bacterial DNA isolation from different dairy products containing Bifidobacterium and Lactobacillus cells. The presence of target DNA and the quality of isolated DNA were checked by polymerase chain reaction (PCR) amplification with specific primers.

  8. Reaction of pharmacological active tris-(2-hydroxyethyl)ammonium 4-chlorophenylsulfanylacetate with ZnCl2 or NiCl2: first conversion of a protic ionic liquid into metallated ionic liquid.

    PubMed

    Mirskova, Anna N; Adamovich, Sergey N; Mirskov, Rudolf G; Schilde, Uwe

    2013-02-19

    The reaction of pharmacological active protic ionic liquid tris-(2-hydroxyethyl)ammonium 4-chlorophenylsulfanylacetate H+N(CH2CH2OH)3 ∙ (-OOCCH2SC6H4Cl-4) (1) with zinc or nickel chloride in a ratio of 2:1 affords stable at room temperature powder-like adducts [H+N(CH2CH2OH)3]2 ∙ [M(OOCCH2SC6H4Cl-4)2Cl2]2-, M = Zn (2), Ni (3). By recrystallization from aqueous alcohol compound 2 unexpectedly gives Zn(OOCCH2SC6H4Cl-4)2 ∙ 2H2O (4). Unlike 2, compound 3 gives crystals [N(CH2CH2OH)3]2Ni2+ · [-OOCCH2SC6H4Cl-4]2 (5), which have a structure of metallated ionic liquid. The structure of 5 has been proved by X-ray diffraction analysis. It is the first example of the conversion of a protic ionic liquid into potentially biological active metallated ionic liquid (1 → 3 → 5).

  9. Synthesis, structural characterization and cell death-inducing effect of novel palladium(II) and platinum(II) saccharinate complexes with 2-(hydroxymethyl)pyridine and 2-(2-hydroxyethyl)pyridine on cancer cells in vitro.

    PubMed

    Ari, Ferda; Aztopal, Nazlihan; Icsel, Ceyda; Yilmaz, Veysel T; Guney, Emel; Buyukgungor, Orhan; Ulukaya, Engin

    2013-11-01

    Four palladium(II) and platinum(II) saccharinate (sac) complexes with 2-(hydroxymethyl)pyridine (2-hmpy) and 2-(2-hydroxyethyl)pyridine (2-hepy), namely trans-[Pd(2-hmpy)2(sac)2]·H2O (1), trans-[Pt(2-hmpy)2(sac)2]·3H2O (2), trans-[Pd(2-hepy)2(sac)2] (3) and trans-[Pt(2-hepy)2(sac)2] (4), have been synthesized and characterized by elemental analysis, UV-vis, IR and NMR. Single crystal X-ray analysis reveals that the metal(II) ions in each complex are coordinated by two sac and two 2-hmpy or 2-hepy ligands with a trans arrangement. Anticancer effects of 1-4 were tested against four different cancer cell lines (A549 and PC3 for lung cancer, C6 for glioblastoma, and Hep3B for liver cancer). Cytotoxicity was first screened by the MTT assay and the results were further confirmed by the ATP assay. The mode of cell death was determined by both histological and biochemical methods. Among the metal complexes, complex 2 resulted in relatively stronger anti-growth effect in a dose-dependent manner (3.13-200μM), compared to the others, by inducing apoptosis.

  10. Reaction of pharmacological active tris-(2-hydroxyethyl)ammonium 4-chlorophenylsulfanylacetate with ZnCl2 or NiCl2: first conversion of a protic ionic liquid into metallated ionic liquid

    PubMed Central

    2013-01-01

    The reaction of pharmacological active protic ionic liquid tris-(2-hydroxyethyl)ammonium 4-chlorophenylsulfanylacetate H+N(CH2CH2OH)3 ∙ (-OOCCH2SC6H4Cl-4) (1) with zinc or nickel chloride in a ratio of 2:1 affords stable at room temperature powder-like adducts [H+N(CH2CH2OH)3]2 ∙ [M(OOCCH2SC6H4Cl-4)2Cl2]2-, M = Zn (2), Ni (3). By recrystallization from aqueous alcohol compound 2 unexpectedly gives Zn(OOCCH2SC6H4Cl-4)2 ∙ 2H2O (4). Unlike 2, compound 3 gives crystals [N(CH2CH2OH)3]2Ni2+ · [-OOCCH2SC6H4Cl-4]2 (5), which have a structure of metallated ionic liquid. The structure of 5 has been proved by X-ray diffraction analysis. It is the first example of the conversion of a protic ionic liquid into potentially biological active metallated ionic liquid (1 → 3 → 5). PMID:23421876

  11. 5-(Bis(3-(2-hydroxyethyl)-1H-indol-2-yl)methyl)-2-hydroxybenzoic acid (BHIMHA): showing a strategy of designing drug to block lung metastasis of tumors

    PubMed Central

    Gan, Taiping; Wang, Yuji; Zhao, Ming; Wu, Jianhui; Yang, Jian; Peng, Shiqi

    2016-01-01

    Early metastasis is still the most recalcitrant factor in the treatment of lung cancer patients. By analyzing the structures and comparing the docking scores of the known pharmacophores, the authors of this paper designed 5-(bis(3-(2-hydroxyethyl)-1H-indol-2-yl)methyl)-2-hydroxybenzoic acid (BHIMHA) as a promising lead compound to develop metastasis inhibitors. In vitro 5, 10, and 20 µM of BHIMHA concentration dependently inhibited the migration and invasion of A549 cells. In vivo 0.4, 2.0, and 8.9 µmol/kg of BHIMHA dose dependently inhibited the metastasis of LLC (Lewis Lung Carcinoma) toward lung. In vivo, 2 µmol/kg of BHIMHA showed additional actions of slowing the growth of the primary tumor of C57BL/6 mice and S180 mice as well as inhibiting xylene-induced ear edema of the mice. Therefore, BHIMHA simultaneously blocked tumor metastasis toward lung, slowed the primary tumor growth, and limited the inflammation. These pharmacological actions were correlated with the inhibition of PKCα and NF-κB expression. PMID:26937173

  12. Preparative isolation of cordycepin, N(6)-(2-hydroxyethyl)-adenosine and adenosine from Cordyceps militaris by macroporous resin and purification by recycling high-speed counter-current chromatography.

    PubMed

    Zhang, Zhong; Tudi, Tuernisan; Liu, Yanfang; Zhou, Shuai; Feng, Na; Yang, Yan; Tang, Chuanhong; Tang, Qingjiu; Zhang, Jingsong

    2016-10-15

    In this study, cordycepin, N(6)-(2-hydroxyethyl)-adenosine (HEA) and adenosine from the fruiting bodies of Cordyceps militaris were separated by using macroporous resin NKA-II adsorption. The parameters of static adsorption were tested and the optimized conditions were as follow: the total adsorption time was 12h, 50% ethanol was used for desorption and the desorption time was 9h. The crude sample that was prepared by macroporous resin NKA-II contained 3.4% cordycepin, 3.7% HEA and 4.9% adenosine. Then the crude sample was further purified by recycling high-speed counter-current chromatography (HSCCC) with ethyl acetate, n-butanol, 1.5% aqueous ammonium hydroxide (1:4:5, v/v/v) as the optimized two-phase solvent system. Three nucleosides including 15.6mg of cordycepin, 16.9mg of HEA and 23.2mg of adenosine were obtained from 500mg of crude sample in one-step separation. The purities of three compounds were 98.5, 98.3 and 98.0%, respectively, as determined by high performance liquid chromatography.

  13. Performance of a Cyanobacteria Whole Cell-Based Fluorescence Biosensor for Heavy Metal and Pesticide Detection

    PubMed Central

    Shing, Wong Ling; Heng, Lee Yook; Surif, Salmijah

    2013-01-01

    Whole cell biosensors always face the challenge of low stability of biological components and short storage life. This paper reports the effects of poly(2-hydroxyethyl methacrylate) (pHEMA) immobilization on a whole cell fluorescence biosensor for the detection of heavy metals (Cu, Pb, Cd), and pesticides (dichlorophenoxyacetic acid (2,4-D), and chlorpyrifos). The biosensor was produced by entrapping the cyanobacterium Anabaena torulosa on a cellulose membrane, followed by applying a layer of pHEMA, and attaching it to a well. The well was then fixed to an optical probe which was connected to a fluorescence spectrophotometer and an electronic reader. The optimization of the biosensor using several factors such as amount of HEMA and drying temperature were undertaken. The detection limits of biosensor without pHEMA for Cu, Cd, Pb, 2,4-D and chlorpyrifos were 1.195, 0.027, 0.0100, 0.025 and 0.025 μg/L respectively. The presence of pHEMA increased the limits of detection to 1.410, 0.250, 0.500, 0.235 and 0.117 μg/L respectively. pHEMA is known to enhance the reproducibility of the biosensor with average relative standard deviation (RSD) of ±1.76% for all the pollutants tested, 48% better than the biosensor without pHEMA (RSD = ±3.73%). In storability test with Cu 5 μg/L, the biosensor with pHEMA performed 11.5% better than the test without pHEMA on day-10 and 5.2% better on day-25. pHEMA is therefore a good candidate to be used in whole cell biosensors as it increases reproducibility and enhances biosensor storability. PMID:23673679

  14. Investigation of yeast invertase immobilization onto cupric ion-chelated, porous, and biocompatible poly(hydroxyethyl methacrylate-n-vinyl imidazole) microspheres.

    PubMed

    Sari, Müfrettin Murat

    2011-04-01

    Cupric ion-chelated poly(hydroxyethyl methacrylate-n-vinyl imidazole) (poly(HEMA-VIM)) microspheres prepared by suspension polymerization were investigated as a specific adsorbent for immobilization of yeast invertase in a batch system. They were characterized by scanning electron microscopy, surface area, and pore size measurements. They have spherical shape and porous structure. The specific surface area of the p(HEMA-VIM) spheres was found to be 81.2 m²/g with a size range of 70-120 μm in diameter, and the swelling ratio was 86.9%. Then, Cu(II) ion chelated on the microspheres (546 μmol Cu(II)/g), and they were used in the invertase adsorption. Maximum invertase adsorption was 51.2 mg/g at pH 4.5. Cu(II) chelation increases the tendency from Freundlich-type to Langmuir-type adsorption model. The optimum activity for both free and adsorbed invertase was observed at pH 4.5. The optimum temperature for the poly(HEMA-VIM)/Cu(II)-invertase system was found to be at 55 °C, 10 °C higher than that of the free enzyme at 45 °C. V(max) values were determined as 342 and 304 U/mg enzyme, for free and adsorbed invertase, respectively. K(m) values were found to be same for free and adsorbed invertase (20 mM). Thermal and pH stability and reusability of invertase increased with immobilization.

  15. Methacrylated glycol chitosan as a photopolymerizable biomaterial.

    PubMed

    Amsden, Brian G; Sukarto, Abby; Knight, Darryl K; Shapka, Stephen N

    2007-12-01

    Glycol chitosan is a derivative of chitosan that is soluble at neutral pH and possesses potentially useful biological properties. With the goal of obtaining biocompatible hydrogels for use as tissue engineering scaffolds or drug delivery depots, glycol chitosan was converted to a photopolymerizable prepolymer through graft methacrylation using glycidyl methacrylate in aqueous media at pH 9. N-Methacrylation was verified by both (1)H NMR and (13)C NMR. The degree of N-methacrylation, measured via (1)H NMR, was easily varied from 1.5% to approximately 25% by varying the molar ratio of glycidyl methacrylate to glycol chitosan and the reaction time. Using a chondrocyte cell line, the N-methacrylated glycol chitosan was found to be noncytotoxic up to a concentration of 1 mg/mL. The prepolymer was cross-linked in solution using UV light and Irgacure 2959 photoinitiator under various conditions to yield gels of low sol content ( approximately 5%), high equilibrium water content (85-95%), and thicknesses of up to 6 mm. Cross-polarization magic-angle spinning (13)C solid state NMR verified the complete conversion of the double bonds in the gel. Chondrocytes seeded directly onto the gel surface, populated the entirety of the gel and remained viable for up to one week. The hydrogels degraded slowly in vitro in the presence of lysozyme at a rate that increased as the cross-link density of the gels decreased.

  16. Dynamic wettability properties of a soft contact lens hydrogel.

    PubMed

    Ketelson, Howard A; Meadows, David L; Stone, Ralph P

    2005-01-15

    The wettability of poly[2-hydroxyethyl methacrylate-co-methacrylic acid] (pHEMA-MAA) soft contact lenses was investigated in the absence and presence of block copolymer surfactants and lysozyme using the sessile drop method. The advancing dynamic contact angles (Thetaw/a) values are reported for water as a function of sequential wetting and drying cycles. The Thetaw/a values for the pHEMA-MAA in the absence of surfactant and lysozyme increased from approximately 20 degrees to 100 degrees as the number of cycles increased from two to ten, and they were independent of the pHEMA-MAA bulk water content. The change from the highly hydrophilic to hydrophobic pHEMA-MAA surface could not be reversed using the sequential wetting and drying cycles even under repeated exposures to saline solution. The effect of block copolymer surfactants with different molecular weights (MW) and hydrophilic-lipophilic balance (HLB) values on the pHEMA-MAA wettability were also studied. Low Theta(w/a) values were observed for pHEMA-MAA hydrogels that were treated with T1304 (MW 10500, HLB 14) and T904 (MW 6700, HLB 15). The surface tension data indicated that these surfactants were incompletely desorbed from the pHEMA-MAA and that the rate of desorption was slow in the timescale of the cycling experiments. Comparatively, poor wettability was observed for pHEMA-MAA surfaces presoaked in T304 (MW 1650, HLB 16) and T1107 (MW 15000, HLB 24) as Thetaw/a values greater than 90 degrees were measured for these surfactants. The surface tension data indicated that the rate of desorption of T304 and T1107 from the pHEMA-MAA was rapid and that they had a low affinity to the pHEMA-MAA. High contact angles were observed for the pHEMA-MAA hydrogels treated with lysozyme and also for the T1107 presoaked pHEMA-MAA that was also treated with lysozyme. Zero wetting angles throughout the sequential cycling were observed for the T1304 pre-treated pHEMA-MAA that had been treated with lysozyme. These results

  17. Characterization and properties of monoammine nitroimidazole complexes of platinum (PtCl sub 2 (NH sub 3 )(NO sub 2 Im)). Crystal and molecular structure of cis-Amminedichloro(1-((((2-hydroxyethyl)amino)carbonyl)methyl)-2-nitroimidazole)platinum(II)

    SciTech Connect

    Rochon, F.D.; Pichang Kong; Melanson, R. ); Skov, K.A. ); Farrell, N. )

    1991-11-27

    The characterization of monoammine(nitroimidazole)platinum(II) complexes of structure (PtCl{sub 2}(NH{sub 3})(NO{sub 2}Im)) (NO{sub 2}Im = 1-((((2-hydroxyethyl)amino)carbonyl)methyl)-2-nitroimidazole, Etanidazole (I), 1-(2-nitro-1-imidazolyl)-3-methoxy2-propanol, Misonidazole (II), and 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole, Metronidazole (III)) is reported. Both is cis and trans isomers may be isolated for II and III. The crystal structure of cis-amminedichloro(1-((((2-hydroxyethyl)amino)carbonyl)methyl)-2-nitroimidazole)platinum(II) has been determined by X-ray diffraction. The crystals are orthorhombic, space group Pnab with cell dimensions a = 14.867 (7) {angstrom}, b = 9.915 (5) {angstrom}, c = 19.015 (9) {angstrom}, and Z = 8. The structure was refined to R = 0.062 and R{sub w} = 0.052. Platinum has the expected square-planar coordination. The Pt-Cl bond trans to the nitroimidazole ligand is shorter (2.269 (3) {angstrom}) than normal. The dihedral angle between the platinum plane and the imidazole ring is 111{degree}, while the nitro group makes an angle of 31{degree} with the imidazole ring plane. Electrochemistry and {sup 195}Pt NMR data are also reported. The relevance of the chemical properties to their biological properties as radiosensitizers and hypoxic cytotoxins is discussed.

  18. Immobilization of type-I collagen and basic fibroblast growth factor (bFGF) onto poly (HEMA-co-MMA) hydrogel surface and its cytotoxicity study.

    PubMed

    Yan, Tuo; Sun, Rong; Li, Chun; Tan, Baihua; Mao, Xuan; Ao, Ningjian

    2010-08-01

    Type-I collagen and bFGF were immobilized onto the surface of poly (HEMA-co-MMA) hydrogel by grafting and coating methods to improve its cytotoxicity. The multi-layered structure of the biocompatible layer was confirmed by FTIR, AFM and static water contact angles. The layers were stable in body-like environment (pH 7.4). Human skin fibroblast cells (HSFC) were seeded onto Col/bFGF-poly (HEMA-co-MMA), Col-poly (HEMA-co-MMA) and poly (HEMA-co-MMA) films for 1, 3 and 5 day. MTT assay was performed to evaluate the extraction toxicity of the materials. Results showed that the cell attachment, proliferation and differentiation on Col/bFGF-poly (HEMA-co-MMA) film were higher than those of the control group, which indicated the improvement of cell-material interaction. The extraction toxicity of the modified materials was also lower than that of the unmodified group. The protein and bFGF immobilized poly (HEMA-co-MMA) hydrogel might hold great promise to be a biocompatible material.

  19. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  20. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  1. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  2. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  3. Influence of calcination temperature on structural and magnetic properties of nanocomposites formed by Co-ferrite dispersed in sol-gel silica matrix using tetrakis(2-hydroxyethyl) orthosilicate as precursor

    PubMed Central

    2011-01-01

    Effects of calcination temperatures varying from 400 to 1000°C on structural and magnetic properties of nanocomposites formed by Co-ferrite dispersed in the sol-gel silica matrix using tetrakis(2-hydroxyethyl) orthosilicate (THEOS) as water-soluble silica precursor have been investigated. Studies carried out using XRD, FT-IR, TEM, STA (TG-DTG-DTA) and VSM techniques. Results indicated that magnetic properties of samples such as superparamagnetism and ferromagnetism showed great dependence on the variation of the crystallinity and particle size caused by the calcination temperature. The crystallization, saturation magnetization Ms and remenant magnetization Mr increased as the calcination temperature increased. But the variation of coercivity Hc was not in accordance with that of Ms and Mr, indicating that Hc is not determined only by the crystallinity and size of CoFe2O4 nanoparticles. TEM images showed spherical nanoparticles dispersed in the silica network with sizes of 10-30 nm. Results showed that the well-established silica network provided nucleation locations for CoFe2O4 nanoparticles to confinement the coarsening and aggregation of nanoparticles. THEOS as silica matrix network provides an ideal nucleation environment to disperse CoFe2O4 nanoparticles and thus to confine them to aggregate and coarsen. By using THEOS as water-soluble silica precursor over the currently used TEOS and TMOS, the organic solvents are not needed owing to the complete solubility of THEOS in water. Synthesized nanocomposites with adjustable particle sizes and controllable magnetic properties make the applicability of Co-ferrite even more versatile. PMID:21486494

  4. N(6)-(2-Hydroxyethyl)adenosine in the Medicinal Mushroom Cordyceps cicadae Attenuates Lipopolysaccharide-Stimulated Pro-inflammatory Responses by Suppressing TLR4-Mediated NF-κB Signaling Pathways.

    PubMed

    Lu, Meng-Ying; Chen, Chin-Chu; Lee, Li-Ya; Lin, Ting-Wei; Kuo, Chia-Feng

    2015-10-23

    Natural products play an important role in promoting health with relation to the prevention of chronic inflammation. N(6)-(2-Hydroxyethyl)adenosine (HEA), a physiologically active compound in the medicinal mushroom Cordyceps cicadae, has been identified as a Ca(2+) antagonist and shown to control circulation and possess sedative activity in pharmacological tests. The fruiting body of C. cicadae has been widely applied in Chinese medicine. However, neither the anti-inflammatory activities of HEA nor the fruiting bodies of C. cicadae have been carefully examined. In this study, we first cultured the fruiting bodies of C. cicadae and then investigated the anti-inflammatory activities of water and methanol extracts of wild and artificially cultured C. cicadae fruiting bodies. Next, we determined the amount of three bioactive compounds, adenosine, cordycepin, and HEA, in the extracts and evaluated their synergistic anti-inflammatory effects. Moreover, the possible mechanism involved in anti-inflammatory action of HEA isolated from C. cicadae was investigated. The results indicate that cordycepin is more potent than adenosine and HEA in suppressing the lipopolysaccharide (LPS)-stimulated release of pro-inflammatory cytokines by RAW 264.7 macrophages; however, no synergistic effect was observed with these three compounds. HEA attenuated the LPS-induced pro-inflammatory responses by suppressing the toll-like receptor (TLR)4-mediated nuclear factor-κB (NF-κB) signaling pathway. This result will support the use of HEA as an anti-inflammatory agent and C. cicadae fruiting bodies as an anti-inflammatory mushroom.

  5. Monitoring ibuprofen enantiomers released from polymeric systems.

    PubMed

    Simó, C; Gallardo, A; Parejo, C; San Román, J; Barbas, C; Cifuentes, A

    2002-07-01

    Two methacrylic derivatives of ibuprofen (N-[4-[2-(4-isobutylphenyl)propionyloxy]phenyl] methacrylamide (MAI) and 2-[(4-isobutylphenyl)propionyloxy]ethyl methacrylate (MEI)) were used together with 2-hydroxyethyl methacrylate (HEMA) to synthesize four polymeric materials: two hydrophobic homopolymers, PMAI and PMEI, and two hydrophilic copolymers containing 70% (w/w) HEMA, MAI-HEMA 30 and MEI-HEMA 30. The enantiomeric determination of R- and S-IBU released from these four systems has been carried out by capillary electrophoresis. Release of R- and S-IBU was monitored during in vitro assays done at 37 degrees C at pH 7.4 and 10 in buffered solutions and rat plasma. There is a hydrolytical activation in plasma and at pH 10 compared to pH 7.4; moreover, the release rate from the copolymers is much higher than from the homopolymers as a consequence of the greater hydrophilic character. A slight excess of the S-enantiomer of IBU is observed in all the experiments, being more relevant at higher release rates, i.e. copolymers at pH 10.

  6. Functionalization of nylon membranes via surface-initiated atom-transfer radical polymerization.

    PubMed

    Xu, F J; Zhao, J P; Kang, E T; Neoh, K G; Li, J

    2007-07-31

    The ability to manipulate and control the surface properties of nylons is of crucial importance to their widespread applications. In this work, surface-initiated atom-transfer radical polymerization (ATRP) is employed to tailor the functionality of the nylon membrane and pore surfaces in a well-controlled manner. A simple two-step method, involving the activation of surface amide groups with formaldehyde and the reaction of the resulting N-methylol polyamide with 2-bromoisobutyryl bromide, was first developed for the covalent immobilization of ATRP initiators on the nylon membrane and its pore surfaces. Functional polymer brushes of 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol)monomethacrylate (PEGMA) were prepared via surface-initiated ATRP from the nylon membranes. A kinetics study revealed that the chain growth from the membranes was consistent with a "controlled" process. The dormant chain ends of the grafted HEMA polymer (P(HEMA)) and PEGMA polymer (P(PEGMA)) on the nylon membranes could be reactivated for the consecutive surface-initiated ATRP to produce the corresponding nylon membranes functionalized by P(HEMA)-b-P(PEGMA) and P(PEGMA)-b-P(HEMA) diblock copolymer brushes. In addition, membranes with grafted P(HEMA) and P(PEGMA) brushes exhibited good resistance to protein adsorption and fouling under continuous-flow conditions.

  7. HemaMax™, a Recombinant Human Interleukin-12, Is a Potent Mitigator of Acute Radiation Injury in Mice and Non-Human Primates

    PubMed Central

    Basile, Lena A.; Ellefson, Dolph; Gluzman-Poltorak, Zoya; Junes-Gill, Katiana; Mar, Vernon; Mendonca, Sarita; Miller, Joseph D.; Tom, Jamie; Trinh, Alice; Gallaher, Timothy K.

    2012-01-01

    HemaMax, a recombinant human interleukin-12 (IL-12), is under development to address an unmet medical need for effective treatments against acute radiation syndrome due to radiological terrorism or accident when administered at least 24 hours after radiation exposure. This study investigated pharmacokinetics, pharmacodynamics, and efficacy of m-HemaMax (recombinant murine IL-12), and HemaMax to increase survival after total body irradiation (TBI) in mice and rhesus monkeys, respectively, with no supportive care. In mice, m-HemaMax at an optimal 20 ng/mouse dose significantly increased percent survival and survival time when administered 24 hours after TBI between 8–9 Gy (p<0.05 Pearson's chi-square test). This survival benefit was accompanied by increases in plasma interferon-γ (IFN-γ) and erythropoietin levels, recovery of femoral bone hematopoiesis characterized with the presence of IL-12 receptor β2 subunit–expressing myeloid progenitors, megakaryocytes, and osteoblasts. Mitigation of jejunal radiation damage was also examined. At allometrically equivalent doses, HemaMax showed similar pharmacokinetics in rhesus monkeys compared to m-HemaMax in mice, but more robustly increased plasma IFN-γ levels. HemaMax also increased plasma erythropoietin, IL-15, IL-18, and neopterin levels. At non-human primate doses pharmacologically equivalent to murine doses, HemaMax (100 ng/Kg and 250 ng/Kg) administered at 24 hours after TBI (6.7 Gy/LD50/30) significantly increased percent survival of HemaMax groups compared to vehicle (p<0.05 Pearson's chi-square test). This survival benefit was accompanied by a significantly higher leukocyte (neutrophils and lymphocytes), thrombocyte, and reticulocyte counts during nadir (days 12–14) and significantly less weight loss at day 12 compared to vehicle. These findings indicate successful interspecies dose conversion and provide proof of concept that HemaMax increases survival in irradiated rhesus monkeys by promoting

  8. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  9. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  10. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  11. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  12. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  13. A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding

    PubMed Central

    Dong, Xiaoqing; Chen, Meng; Wang, Yong; Yu, Qingsong

    2014-01-01

    Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm−1 and amide II at 1550 cm−1, which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding. PMID:25267936

  14. A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding.

    PubMed

    Dong, Xiaoqing; Chen, Meng; Wang, Yong; Yu, Qingsong

    2014-07-01

    Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm(-1) and amide II at 1550 cm(-1), which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding.

  15. Clinical Significance of Bis-GMA and HEMA Orthodontic Resins Bonding to Enamel and Ceramic Materials.

    PubMed

    Reichheld, Timothy; Monfette, Gregory; Perry, Ronald D; Finkelman, Matthew; Gheewalla, Eric; Kugel, Gerard

    The advancement of new ceramic materials for dental crowns has prompted the need for improved methods of bonding orthodontic brackets to these surfaces. Currently, lithium-disilicate is the primary material being used for anterior crowns, while zirconia is the primary material being used in the posterior. The purpose of this study was to compare the shear bond strength of HEMA (Assure® Universal Bonding Resin) and bis-GMA (Assure® PLUS All Surface Bonding Resin) orthodontic bonding resins on enamel, lithium-disilicate, and zirconia materials. Two groups were formed, with three tested surfaces per group (n = 20). The categories included premolars, zirconia rods, and lithium-disilicate rods. Group 1 was treated with Assure, and group 2 was treated with Assure PLUS. Zirconia rods (1 cm x 1 cm x 4 cm) were used to represent zirconia crowns, and IPS e.max CAD rods (1 cm x 1 cm x 2 cm) were used to represent lithium-disilicate crowns. Assure and Assure PLUS bonding agents were applied according to the manufacturer's specifications, and standard edgewise universal premolar brackets were secured using Light Bond™ paste without fluoride. After 24 hours the brackets were sheared with a universal testing machine (Instron® 5566A) and the results were recorded. Data were analyzed using a combination of ANOVA and Tukey tests. A P value of less than .05 was considered statistically significant. Although group 1 and group 2 gave statistically equivalent results, the authors found that the ease of use when applying the group 2 bonding agent made it a safer, superior product within the confines of this study. It did not require a 4-minute hydrofluoric acid-etch and needed half the curing time of the group 1 agent when bonding to ceramic materials.

  16. pH-sensitive methacrylic copolymers and the production thereof

    SciTech Connect

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2007-01-09

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  17. pH-sensitive methacrylic copolymers and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2006-02-14

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  18. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the...

  19. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the...

  20. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the...

  1. Photocontrol over the disorder-to-order transition in thin films of polystyrene-block-poly(methyl methacrylate) block copolymers containing photodimerizable anthracene functionality.

    PubMed

    Chen, Wei; Wang, Jia-Yu; Zhao, Wei; Li, Le; Wei, Xinyu; Balazs, Anna C; Matyjaszewski, Krzysztof; Russell, Thomas P

    2011-11-02

    Reversible photocontrol over the ordering transition of block copolymers (BCPs) from a disordered state to an ordered state, namely the disorder-to-order transition (DOT), can be used to create long-range ordered nanostructures in self-assembled BCPs over macroscopic distances by photocombing, similar to the classic zone refining used to produce highly pure, large single crystals. Here, we have designed and synthesized an anthracene-functionalized tri-BCP containing deuterated polystyrene (d(8)-PS) and poly(methyl methacrylate) (PMMA) blocks, as well as a short middle block of poly(2-hydroxyethyl methacrylates) (PHEMA) that is randomly functionalized by anthracene. This tri-BCP maintains the order-to-disorder transition-type phase behavior of its parent d(8)-PS-b-PMMA di-BCPs. Under 365 nm UV irradiation, the junction between d(8)-PS and PMMA blocks is photocoupled through the anthracene photodimers, leading to a significant increase in the total molecular weight of the tri-BCP. As a consequence, when the tri-BCP is phase-mixed but close to the boundary of the ordering transition, it undergoes the DOT, as evidenced by small-angle neutron scattering and transmission electron microscopy. The tri-BCP could be reversibly brought through the DOT in thin films by taking advantage of photodimerization and thermal dissociation of anthracene. Currently, anthracene-functionalized d(8)-PS-b-PMMA BCP is one of the most promising candidates for the photocombing process to promote long-range laterally ordered nanostructures over macroscopic distances in a noninvasive manner.

  2. Buffer Standards for pH Measurement of N-(2-Hydroxyethyl)piperazine-N'-2-ethanesulfonic Acid (HEPES) for I = 0.16 mol.kg from 5 to 55 degrees C.

    PubMed

    Roy, Rabindra N; Roy, Lakshmi N; Ashkenazi, Shahaf; Wollen, Joshua T; Dunseth, Craig D; Fuge, Michael S; Durden, Jared L; Roy, Chandra N; Hughes, Hannah M; Morris, Brett T; Cline, Kevin L

    2009-04-01

    The values of the second dissociation constant, pK(2) of N-(2-hydroxyethyl) piperazine-N'-2-ethanesulfonic acid (HEPES) have been reported at 12 temperatures over the temperature range 5 to 55 degrees C, including 37 degrees C. This paper reports the results for the pa(H) of eight isotonic saline buffer solutions with an I = 0.16 mol*kg(-1) including compositions: (a) HEPES (0.01 mol*kg(-1)) + NaHEPES (0.01 mol*kg(-1)) + NaCl (0.15 mol*kg(-1)); (b) HEPES (0.02 mol*kg(-1)) + NaHEPES (0.02 mol*kg(-1)) + NaCl (0.14 mol*kg(-1)); (c) HEPES (0.03 mol*kg(-1)) + NaHEPES (0.03 mol*kg(-1)) + NaCl (0.13 mol*kg(-1)); (d) HEPES (0.04 mol*kg(-1)) + NaHEPES (0.04 mol*kg(-1)) + NaCl (0.12 mol*kg(-1)); (e) HEPES (0.05 mol*kg(-1)) + NaHEPES (0.05 mol*kg(-1)) + NaCl (0.11 mol*kg(-1)); (f) HEPES (0.06 mol*kg(-1)) + NaHEPES (0.06 mol*kg(-1)) + NaCl (0.10 mol*kg(-1)); (g) HEPES (0.07 mol*kg(-1)) + NaHEPES (0.07 mol*kg(-1)) + NaCl (0.09 mol*kg(-1)); and (h) HEPES (0.08 mol*kg(-1)) + NaHEPES (0.08 mol*kg(-1)) + NaCl (0.08 mol*kg(-1)). Conventional pa(H) values, for all eight buffer solutions from 5 to 55 degrees C have been calculated. The operational pH values with liquid junction corrections, at 25 and 37 degrees C have been determined based on the NBS/NIST standard between the physiological phosphate standard and four buffer solutions. These are recommended as pH standards for physiological fluids in the range of pH 7.3 to 7.5 at I = 0.16 mol*kg(-1).

  3. hemaClass.org: Online One-By-One Microarray Normalization and Classification of Hematological Cancers for Precision Medicine

    PubMed Central

    Falgreen, Steffen; Ellern Bilgrau, Anders; Brøndum, Rasmus Froberg; Hjort Jakobsen, Lasse; Have, Jonas; Lindblad Nielsen, Kasper; El-Galaly, Tarec Christoffer; Bødker, Julie Støve; Schmitz, Alexander; H. Young, Ken; Johnsen, Hans Erik; Dybkær, Karen; Bøgsted, Martin

    2016-01-01

    Background Dozens of omics based cancer classification systems have been introduced with prognostic, diagnostic, and predictive capabilities. However, they often employ complex algorithms and are only applicable on whole cohorts of patients, making them difficult to apply in a personalized clinical setting. Results This prompted us to create hemaClass.org, an online web application providing an easy interface to one-by-one RMA normalization of microarrays and subsequent risk classifications of diffuse large B-cell lymphoma (DLBCL) into cell-of-origin and chemotherapeutic sensitivity classes. Classification results for one-by-one array pre-processing with and without a laboratory specific RMA reference dataset were compared to cohort based classifiers in 4 publicly available datasets. Classifications showed high agreement between one-by-one and whole cohort pre-processsed data when a laboratory specific reference set was supplied. The website is essentially the R-package hemaClass accompanied by a Shiny web application. The well-documented package can be used to run the website locally or to use the developed methods programmatically. Conclusions The website and R-package is relevant for biological and clinical lymphoma researchers using affymetrix U-133 Plus 2 arrays, as it provides reliable and swift methods for calculation of disease subclasses. The proposed one-by-one pre-processing method is relevant for all researchers using microarrays. PMID:27701436

  4. Analysis of the addition of a crosslinking agent in pyrromethene-HEMA based photopolymerizable holographic recording materials

    NASA Astrophysics Data System (ADS)

    Blaya, S.; Acebal, P.; Carretero, L.; Madrigal, R. F.; Murciano, A.; Fimia, A.

    2011-06-01

    In this work, we present the analysis of a photopolymerizable system based on pyrromethene dye (PM567) acting as a photoinitiator and HEMA as monomer both of them dissolved in a dry polymeric matrix of PMMA. Previously, we reported the recording of diffraction gratings in this composition, resulting in diffraction efficiencies near 60 % with exposures of 1 J/cm2 in materials with thicknesses around 500 microns. Although, the mentioned response (best) was observed at low intensities but at higher ones lower diffraction efficiencies were reached. Furthermore, in all the studied cases inhibition periods with asymmetrical angular selectivity curves were obtained. Since, in order to solve the mentioned drawbacks, the aim of this work is to analyze the effect of the addition of a crosslinking agent (PETA) in a photopolymerizable holographic material based on a pyrromethene dye (PM567) acting as a photoinitiator and HEMA as monomer both of them dissolved in a dry polymeric matrix of PMMA. For this, diffraction gratings were recorded at different intensities and the energetic evolution of the diffraction efficiency as well as the observed inhibition period were studied as a function of the concentration of crosslinking agent. Moreover, the experimental angular selectivity curves were theoretically analyzed by the model of Kubota and Uchida, and as a result information such as the effective thickness, fringe bending and non-uniform index modulation against the thickness of grating was obtained.

  5. Dendrimer/methyl methacrylate co-polymers: residual methyl methacrylate and degree of conversion.

    PubMed

    Viljanen, Eeva K; Skrifvars, Mikael; Vallittu, Pekka K

    2005-01-01

    Dendrimer/methyl methacrylate co-polymers were studied for use in dental composites. The aim was to determine the effects of methyl methacrylate concentration in the resin mixture and polymerization method on the degree of conversion and residual monomer content of the copolymers. Two dendrimers were studied, D12 with 12 reactive methacrylate groups and D24 with 24 reactive groups. The concentration of methyl methacrylate varied from 20 wt% to 50 wt% of monomers. Camphorquinone (CQ) was used as the light-activation initiator and 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) as the activator, both in the quantity of 3.0 wt%. Three polymerization methods were used: photo-polymerization, photo-polymerized immediately followed by post-polymerization at 120 degrees C for 15 min, and photo-polymerization followed by postpolymerization after 7 days. The degree of conversion was determined using FT-IR. Residual monomers were extracted with tetrahydrofuran and methanol and analyzed with HPLC. The highest degrees of conversion were 65 and 62%, and the lowest residual monomer contents 1.0 and 1.5% for D12 and D24, respectively. These were measured after heat-induced post-polymerization. For D12, increasing the proportion of methyl methacrylate decreased the degree of conversion and increased the residual monomer content after photo-polymerization. Post-polymerization enhanced the polymerization of the dendrimer co-polymers in respect of degree of conversion and residual monomer content. The present study suggested that the tested dendrimer/methyl methacrylate copolymers require heat-induced polymerization to reach the generally accepted levels of degree of conversion and residual monomers.

  6. Investigation of eluted monomers from resin-based root canal sealer by high-performance liquid chromatography analysis

    PubMed Central

    Omurlu, Huma; Arisu, Hacer Deniz; Dalkilic, Evrim Eliguzeloglu; Tamer, Ugur; Torul, Hilal

    2016-01-01

    Objective: The purpose of the current study was to determine the amount of urethane dimethacrylate (UDMA), bisphenol A-glycidyl methacrylate (Bis-GMA), poly (ethylene glycol) dimethacrylate (PEGDMA), bisphenol A ethoxylated dimethacrylate (Bis-EMA), and 2-hydroxyethyl methacrylate (HEMA) eluted from resin-based root canal sealer, epiphany, using high-performance liquid chromatography (HPLC). Materials and Methods: Epiphany was placed into the plastic molds and light-cured with a light emitting diode. After the curing process, each specimen in the first group (n = 12) was immersed in Eppendorf tubes containing a phosphate-buffered saline solution (PBS) and incubated for 45 s. In the second group, each specimen (n = 12) was immersed in Eppendorf tubes containing PBS and incubated for 24 h. Of the specimen extracts, 100 μL were subjected to HPLC. Analysis of data was accomplished with one-way analysis of variance (P < 0.05). Results: All of the samples eluted HEMA, UDMA, Bis-GMA, PEGDMA, and Bis-EMA. A significant difference was determined between the time periods of HEMA, UDMA, PEGDMA, and Bis-EMA (P < 0.05). Conclusion: The results of the current study showed that Epiphany releases HEMA, UDMA, Bis-GMA, PEGDMA, and Bis-EMA in both time periods. PMID:27011746

  7. 10 kHz repetition rate solid-state dye laser pumped by diode-pumped solid-state laser

    NASA Astrophysics Data System (ADS)

    Abedin, K. M.; Álvarez, M.; Costela, A.; García-Moreno, I.; García, O.; Sastre, R.; Coutts, D. W.; Webb, C. E.

    2003-04-01

    We describe the operation of an all solid-state pulsed dye laser of high repetition rate (10 kHz) pumped by a diode-pumped laser. Three different active media in the form of coin-sized disks were investigated: the dye rhodamine 6G doped in a copolymer of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) [Rh6G/P(MMA:HEMA)], and the dye pyrromethene 567 (PM567) doped in copolymers of MMA with pentaerythritol triacrylate (PETA) and with pentaerythritol tetraacrylate (PETRA) [PM567/P(MMA:PETA) and PM567/P(MMA:PETRA)]. Pump radiation at 527nm was provided by a frequency-doubled diode-pumped Nd:YLF laser Q-switched at 10 kHz. Laser output was observed with an initial average power of 560 mW for Rh6G in P(MMA:HEMA), and with an initial average power of 430 mW for PM567 in P(MMA:PETRA) and 220 mW for PM567 in P(MMA:PETA). In the case of Rh6G/P(MMA:HEMA), the output decreased to about half the initial value after about 6.6 min (or about 4.0 million shots) due to dye degradation. The device constitutes a tunable, all solid-state, high repetition rate laser system possibly suitable for biomedical and dermatological applications.

  8. Highly efficient and photostable solid-state dye lasers based on modified copolymers doped with PM567

    NASA Astrophysics Data System (ADS)

    Jiang, Yugang; Fan, Rongwei; Xia, Yuanqin; Chen, Deying

    2011-04-01

    Solid-state dye samples based on modified copolymers of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) with methanol doped with PM567 were first prepared. The volume proportions of methanol have great effects on the laser's characteristics including spectra, lasing output and thermal properties. The highest slope efficiency of 64.25% was achieved in the sample MP (MMA:HEMA = 85:15 + 10% methanol). Pumping the samples at a repetition rate of 5 Hz with a pulse energy as high as 100 mJ (the fluence was 0.26 J/cm2), the maximum lifetime of 278,000 shots was obtained in the sample MP (MMA:HEMA = 85:15 + 15% methanol), and the corresponding normalized photostability reached 180.7 GJ/mol. The obtained ten-shots damage thresholds were as high as 6.7 J/cm2. The results indicate that the laser properties of solid-state dyes can be greatly enhanced by using modified copolymers of MMA and HEMA with methanol as solid hosts.

  9. A new metal-chelated cryogel for reversible immobilization of urease.

    PubMed

    Uygun, Murat; Akduman, Begüm; Akgöl, Sinan; Denizli, Adil

    2013-08-01

    Poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) [poly(HEMA-GMA)] cryogel was synthesized by cryopolymerization technique at frozen temperature. Iminodiacetic acid (IDA) was then attached covalently to the cryogel as a chelating agent. Then, poly(HEMA-GMA)-IDA cryogel was chelated with Ni(II) ions and this novel metal affinity support was used for adsorption of urease from its aqueous solution. Urease adsorption experiments were carried out in a continuous system by using a peristaltic pump. Maximum urease adsorption onto poly(HEMA-GMA)-IDA-Ni(II) cryogel was found to be 11.30 mg/g cryogel at pH 5.0 acetate buffer and in 25 °C medium temperature. Urease adsorption capacity decreased with increasing ionic strength and increasing chromatographic flow rate. Adsorption kinetics of urease onto poly(HEMA-GMA)-IDA-Ni(II) cryogel was also investigated and it was found that Langmuir adsorption model is applicable for this adsorption study. This novel immobilized metal affinity chromatography support was used 10 times without any decrease at their adsorption capacity. It was also observed that urease enzyme was repeatedly adsorbed and desorbed without significant lost in enzymatic activity.

  10. Enhancement in dose sensitivity of polymer gel dosimeters composed of radiation-crosslinked gel matrix and less toxic monomers

    NASA Astrophysics Data System (ADS)

    Hiroki, A.; Yamashita, S.; Taguchi, M.

    2015-01-01

    Polymer gel dosimeters based on radiation-crosslinked hydroxypropyl cellulose gel were prepared, which comprised 2-hydroxyethyl methacrylate (HEMA) and polyethylene glycol #400 dimethacrylate (9G) as less toxic monomers and tetrakis (hydroxymethyl) phosphonium chloride (THPC) as an antioxidant. The dosimeters exposed to 60Co γ-rays became cloudy at only 1 Gy. The irradiated dosimeters were optically analyzed by using a UV- vis spectrophotometer to evaluate dose response. Absorbance of the dosimeters linearly increased in the dose range from 0 to 10 Gy, in which dose sensitivity increased with increasing 9G concentration. The dose sensitivity of the dosimeters with 2 wt% HEMA and 3 wt% 9G was also enhanced by increment in THPC.

  11. Complement-induced thrombus formation on the surface of poly(N-vinylpyrrolidone)-grafted polyethylene.

    PubMed

    Fukumura, H; Hayashi, K; Yoshikawa, S; Miya, M; Yamamoto, N; Yamashita, I

    1987-01-01

    The role of complement activation in thrombogenesis was investigated on the surface of hydrophilic monomer-graft copolymerized polyethylene (PE) tubes. N-vinylpyrrolidone (NVP)-grafted tubes activated in an in vitro complement system of canine serum; but no activation occurred in 2-hydroxyethyl methacrylate (HEMA)-grafted tubes. The relative patent time for NVP-grafted tubes implanted in canine peripheral veins was shorter than that for HEMA-grafted tubes and adhesion of numerous leucocytes was observed on the luminal surfaces of the NVP-grafted tubes. Decomplementation by prior administration of cobra venom factor elongated the relative patent time for NVP-grafted tubes only and also inhibited the adhesion of leucocytes onto them. These results suggest that the complement activation participates in thrombus formation on the polymer surfaces in canine veins.

  12. Chitosan-nanohydroxyapatite composites: mechanical, thermal and bio-compatibility studies.

    PubMed

    Roy, Pratik; Sailaja, R R N

    2015-02-01

    Bionanocomposites of chitosan were prepared with nanohydroxyapatite (nHA) using 2-hydroxyethyl methacrylate (HEMA) as coupling agent. The tensile and flexural properties for 8% nHA loading showed optimal values. Compressive modulus also considerably increased from 525.16 MPa (0% nHA) to 1326.5 MPa with 10% nHA. Surface functionalization of fillers along with the addition of HEMA as coupling agent led to enhanced mechanical properties similar to human bone. The mechanical properties were further analyzed using micromechanical theories which indicated good interfacial adhesion between the matrix and fillers. The composites showed cytocompatibility. Multiple layers of apatite formation have been observed when the nanocomposites were soaked in simulated body fluid (SBF). Hence, these composites showed potential for bone substitute applications.

  13. A novel application of UV-LEDs in the contact lens manufacturing process

    NASA Astrophysics Data System (ADS)

    McDermott, Sharon; Walsh, James E.; Howard, Robert G.

    2005-06-01

    The majority of soft contact lenses are manufactured using a process of ultraviolet (UV) radiation initiated photopolymerisation. The main source of UV radiation in this manufacturing process is from UV fluorescent lamps. However, there are a number of disadvantages to these lamps, namely, their intensity varies over time and has to be constantly monitored. This paper presents a comparison between light emitting diodes (LEDs), which emit in the UV, and fluorescent lamps used in the contact lens manufacturing industry. The spectral and temporal stability of both UV sources is presented. The ability of both sources to photopolymerise 2-Hydroxyethyl Methacrylate (HEMA), the main component of soft contact lenses, was measured using FTIR and Raman spectroscopy. The percentage polymerisation of HEMA, using both sources, was calculated for several UV sensitive photoinitiators and is presented here. The potential of these UV-LEDs in replacing fluorescent lamps in contact lens manufacturing is discussed.

  14. "Click" Chemistry-Tethered Hyaluronic Acid-Based Contact Lens Coatings Improve Lens Wettability and Lower Protein Adsorption.

    PubMed

    Deng, Xudong; Korogiannaki, Myrto; Rastegari, Banafsheh; Zhang, Jianfeng; Chen, Mengsu; Fu, Qiang; Sheardown, Heather; Filipe, Carlos D M; Hoare, Todd

    2016-08-31

    Improving the wettability of and reducing the protein adsorption to contact lenses may be beneficial for improving wearer comfort. Herein, we describe a simple "click" chemistry approach to surface functionalize poly(2-hydroxyethyl methacrylate) (pHEMA)-based contact lenses with hyaluronic acid (HA), a carbohydrate naturally contributing to the wettability of the native tear film. A two-step preparation technique consisting of laccase/TEMPO-mediated oxidation followed by covalent grafting of hydrazide-functionalized HA via simple immersion resulted in a model lens surface that is significantly more wettable, more water retentive, and less protein binding than unmodified pHEMA while maintaining the favorable transparency, refractive, and mechanical properties of a native lens. The dipping/coating method we developed to covalently tether the HA wetting agent is simple, readily scalable, and a highly efficient route for contact lens modification.

  15. Synthesis and evaluation of novel dental monomer with branched carboxyl acid group

    PubMed Central

    Song, Linyong; Ye, Qiang; Ge, Xueping; Misra, Anil; Laurence, Jennifer S.; Berrie, Cynthia L.; Spencer, Paulette

    2014-01-01

    To enhance the water miscibility and increase the mechanical properties of dentin adhesives, a new glycerol-based monomer with vinyl and carboxylic acid, 4-((1,3-bis(-methacryloyloxy)propan-2-yl)oxy)-2-methylene-4-oxobutanoic acid (BMPMOB), was synthesized and characterized. Dentin adhesive formulations containing 2-hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (BisGMA), and BMPMOB were characterized with regard to real-time photopolymerization behavior, water sorption, dynamic mechanical analysis, and microscale three-dimensional internal morphologies and compared with HEMA/BisGMA controls. The experimental adhesive copolymers showed higher glass transition temperature and rubbery moduli, as well as improved water miscibility compared to the controls. The enhanced properties of the adhesive copolymers indicated that BMPMOB is a promising comonomer for dental restorative materials. PMID:24596134

  16. Effect of methacrylic acid:methyl methacrylate monomer ratios on polymerization rates and properties of polymethyl methacrylates.

    PubMed

    Chen, T; Kusy, R P

    1997-08-01

    Five binary formulations were prepared from methyl methacrylate (MMA) and methacrylic acid (MAA) monomers, and six ternary formulations were prepared from polysols of 30% wt polymethyl methacrylate (PMMA)/MMA and MAA. Using thermal analyses (DSC and TGA) the polymerization kinetics, condition of postcuring, relative amount of residual monomers, and glass transition temperature (Tg) were determined. From bar-shaped samples, 25 x 5 x 0.9 mm in dimensions, mechanical properties [flexural moduli (E) and maximum strengths (sigma)] were measured in three-point bending. Polymerization kinetics of binary formulations improved over pure PMMA (from 15 to 4 min) as a result of over a 60-fold increase in propagation-to-termination constants (Kp/Kt) of MAA/MMA. The further addition of PMMA increased the viscosity, slowed down termination, and, consequently, improved the polymerization kinetics twofold. These enhancements occurred without a substantive change in the Tg of the ternary system (ca. 107 degrees C) over pure PMMA (ca. 112 degrees C). Moreover, the Es of the four ternary formulations averaged 2.94 GPa, which was comparable with many values reported in the literature. In contrast the sigma s of these same formulations averaged 97 MPa, which was about 25% better than earlier investigations of pure acrylic. When a thermoplastic material is required for pultruding profiles that cure fast and have good thermal-mechanical properties, ternaries of PMMA/MMA/MAA should be considered.

  17. Molecular recognition based iron removal from human plasma with imprinted membranes.

    PubMed

    Yavuz, H; Andaç, M; Uzun, L; Say, R; Denizli, A

    2006-09-01

    The aim of this study is to prepare ion-imprinted poly(2-hydroxyethyl methacrylate) (HEMA) based membranes which can be used for the selective removal of Fe3+ ions from Fe3+-overdosed human plasma. N-methacryloyl-(L)-glutamic acid (MAGA) was chosen as the ion-complexing monomer. In the first step, Fe3+ was complexed with MAGA and then, the Fe3+-imprinted poly(HEMA-MAGA) membranes were prepared by UV-initiated photo-polymerization of HEMA and MAGA-Fe3+ complex in the presence of an initiator (benzoyl peroxide). After that, the template (i.e., Fe3+ ions) was removed by using 0.1 M EDTA solution at room temperature. The specific surface area of the Fe3+-imprinted poly(HEMA-MAGA) membranes was found to be 49.2 m2/g and the swelling ratio was 92%. According to the elemental analysis results, the polymeric membranes contained 145.7 micromol MAGA/g polymer. The maximum adsorption capacity was 164.2 micromol Fe3+/g membrane. The relative selectivity coefficients of ion-imprinted membranes for Fe3+/Zn2+ and Fe3+/Cr3+ were 12.6 and 62.5 times greater than the non-imprinted matrix, respectively. The Fe3+-imprinted poly(HEMA-MAGA) membranes could be used many times without decreasing their Fe3+ adsorption capacities significantly.

  18. Growth of Ag nanoparticles using plasma-modified multi-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Tseng, Chun-Hao; Chen, Chuh-Yung

    2008-01-01

    This study presents a novel method for preparing multi-walled carbon nanotubes (MWNTs) grafted with a poly(2-hydroxyethyl methacrylate) (HEMA)-silver complex (CNTs-HEMA-Ag complex) through plasma-induced grafting polymerization. The characteristics of the MWNTs after being grafted with HEMA polymer are monitored by Fourier transform infrared (FT-IR) spectroscopy. The chelating groups in the HEMA polymer grafted on the surface of the CNTs-HEMA are the coordination sites for chelating silver ions, and are further used as nanotemplates for the growing of Ag nanoparticles (quantum dots). Transmission electron microscopy (TEM) reveals that the particle size of Ag nanoparticles on the CNT surfaces increases with the Ag+ chelating concentration, reaction time, and reaction temperature. Moreover, the crystalline phase of Ag nanoparticles is identified by using x-ray diffraction (XRD). In addition, high-resolution x-ray photoelectron spectroscopy (XPS) is used to characterize the functional groups on the surface of the MWNTs after chemical modification through plasma treatment; it demonstrates that the growing amount of the Ag nanoparticles on the nanotubes increases with the Ag+ chelating concentration due to the blocking effect of the Ag particles forming on the MWNTs.

  19. A pre-formed methyl methacrylate cranioplasty.

    PubMed

    Cooper, P R; Schechter, B; Jacobs, G B; Rubin, R C; Wille, R L

    1977-09-01

    The use of a pre-formed methyl methacrylate cranioplasty prosthesis reinforced with stainless steel wire is described. The prosthesis is non-reactive, virtually unbreakable, and undentable. Pre-forming of the prosthesis in the dental laboratory using a mold of the patient's bony defect as a model saves considerable operating time, and when employed for a large cranial defect the three dimensional cosmetic effect is superior to intra-operatively fashioned prostheses.

  20. Anisotropic polymer composites synthesized by immobilizing cellulose nanocrystal suspensions specifically oriented under magnetic fields.

    PubMed

    Tatsumi, Mio; Kimura, Fumiko; Kimura, Tsunehisa; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2014-12-08

    Novel polymer composites reinforced with an oriented cellulose nanocrystal (CNC) assembly were prepared from suspensions of CNC in aqueous 2-hydroxyethyl methacrylate (HEMA) via magnetic field application to the suspensions followed by polymerization treatment. The starting suspensions used at ∼6 wt % CNC separated into an upper isotropic phase and a lower anisotropic (chiral nematic) one in the course of quiescent standing. A static or rotational magnetic field was applied to the isolated isotropic and anisotropic phases. UV-induced polymerization of HEMA perpetuated the respective states of magnetic orientation invested for the CNC dispersions to yield variously oriented CNC/poly(2-hydroxyethyl methacrylate) composites. The structural characterization was carried out by use of X-ray diffractometry and optical and scanning electron microscopy. The result indicated that CNCs were aligned in the composites distinctively according to the static or rotational magnetic application when the anisotropic phases were used, whereas such a specific CNC orientation was not appreciable when the isotropic phases were sampled. This marks out effectiveness of a coherent response of CNCs in the mesomorphic assembly. In dynamic mechanical experiments in tensile or compressive mode, we observed a clear mechanical anisotropy for the polymer composites synthesized from wholly anisotropic suspensions under static or rotational magnetization. The higher modulus (in compression) was detected for a composite reinforced by locking-in the uniaxial CNC alignment attainable through conversion of the initial chiral nematic phase into a nematic phase in the rotational magnetic field.

  1. Allergic contact dermatitis from acrylic nails in a flamenco guitarist.

    PubMed

    Alcántara-Nicolás, F A; Pastor-Nieto, M A; Sánchez-Herreros, C; Pérez-Mesonero, R; Melgar-Molero, V; Ballano, A; De-Eusebio, E

    2016-12-01

    Acrylates are molecules that are well known for their strong sensitizing properties. Historically, many beauticians and individuals using store-bought artificial nail products have developed allergic contact dermatitis from acrylates. More recently, the use of acrylic nails among flamenco guitarists to strengthen their nails has become very popular. A 40-year-old non-atopic male patient working as a flamenco guitarist developed dystrophy, onycholysis and paronychia involving the first four nails of his right hand. The lesions were confined to the fingers where acrylic materials were used in order to strengthen his nails to play the guitar. He noticed improvement whenever he stopped using these materials and intense itching and worsening when he began reusing them. Patch tests were performed and positive results obtained with 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxyethyl acrylate (2-HEA), ethyleneglycol-dimethacrylate (EGDMA) and 2-hydroxypropyl methacrylate (2-HPMA). The patient was diagnosed with occupational allergic contact dermatitis likely caused by acrylic nails. Artificial nails can contain many kinds of acrylic monomers but most cases of contact dermatitis are induced by 2-HEMA, 2-HPMA and EGDMA. This is the first reported case of occupational allergic contact dermatitis from acrylates in artificial nails in a professional flamenco guitar player. Since the practice of self-applying acrylic nail products is becoming very popular within flamenco musicians, we believe that dermatology and occupational medicine specialists should be made aware of the potentially increasing risk of sensitization from acrylates in this setting.

  2. Reactivity of methacrylates in insertion polymerization.

    PubMed

    Rünzi, Thomas; Guironnet, Damien; Göttker-Schnetmann, Inigo; Mecking, Stefan

    2010-11-24

    Polymerization of ethylene by complexes [{(P^O)PdMe(L)}] (P^O = κ(2)-(P,O)-2-(2-MeOC(6)H(4))(2)PC(6)H(4)SO(3))) affords homopolyethylene free of any methyl methacrylate (MMA)-derived units, even in the presence of substantial concentrations of MMA. In stoichiometric studies, reactive {(P^O)Pd(Me)L} fragments generated by halide abstraction from [({(P^O)Pd(Me)Cl}μ-Na)(2)] insert MMA in a 1,2- as well as 2,1-mode. The 1,2-insertion product forms a stable five-membered chelate by coordination of the carbonyl group. Thermodynamic parameters for MMA insertion are ΔH(++) = 69.0(3.1) kJ mol(-1) and ΔS(++) = -103(10) J mol(-1) K(-1) (total average for 1,2- and 2,1-insertion), in comparison to ΔH(++) = 48.5(3.0) kJ mol(-1) and ΔS(++) = -138(7) J mol(-1) K(-1) for methyl acrylate (MA) insertion. These data agree with an observed at least 10(2)-fold preference for MA incorporation vs MMA incorporation (not detected) under polymerization conditions. Copolymerization of ethylene with a bifunctional acrylate-methacrylate monomer yields linear polyethylenes with intact methacrylate substituents. Post-polymerization modification of the latter was exemplified by free-radical thiol addition and by cross-metathesis.

  3. Dimensional accuracy of thermoformed polymethyl methacrylate.

    PubMed

    Jagger, R G

    1996-12-01

    Thermoforming of polymethyl methacrylate sheet is used to produce a number of different types of dental appliances. The purpose of this study was to determine the dimensional accuracy of thermoformed polymethyl methacrylate specimens. Five blanks of the acrylic resin were thermoformed on stone casts prepared from a silicone mold of a brass master die. The distances between index marks were measured both on the cast and on the thermoformed blanks with an optical comparator. Measurements on the blanks were made again 24 hours after processing and then 1 week, 1 month, and 3 months after immersion in water. Linear shrinkage of less than 1% (range 0.37% to 0.52%) was observed 24 hours after removal of the blanks from the cast. Immersion of the thermoformed specimens in water resulted in an increase in measured dimensions, but after 3 months' immersion these increases were still less than those of the cast (range 0.07% to 0.18%). It was concluded that it is possible to thermoform Perspex polymethyl methacrylate accurately.

  4. Confined compression and torsion experiments on a pHEMA gel in various bath concentrations.

    PubMed

    Roos, Reinder W; Petterson, Rob; Huyghe, Jacques M

    2013-06-01

    The constitutive behaviour of cartilaginous tissue is the result of complex interaction between electrical, chemical and mechanical forces. Electrostatic interactions between fixed charges and mobile ions are usually accounted for by means of Donnan osmotic pressure. Recent experimental data show, however, that the shear modulus of articular cartilage depends on ionic concentration even if the strain is kept constant. Poisson-Boltzmann simulations suggest that this dependence is intrinsic to the double-layer around the proteoglycan chains. In order to verify this premise, this study measures whether--at a given strain--this ionic concentration-dependent shear modulus is present in a polymerized hydroxy-ethyl-methacrylate gel or not. A combined 1D confined compression and torque experiment is performed on a thin cylindrical hydrogel sample, which is brought in equilibrium with, respectively, 1, 0.1 and 0.03 M NaCl. The sample was placed in a chamber that consists of a stainless steel ring placed on a sintered glass filter, and on top a sintered glass piston. Stepwise ionic loading was cascaded by stepwise 1D compression, measuring the total stress after equilibration of the sample. In addition, a torque experiment was interweaved by applying a harmonic angular displacement and measuring the torque, revealing the relation between aggregate shear modulus and salt concentration at a given strain.

  5. Control of hemA Expression in Rhodobacter sphaeroides 2.4.1: Effect of a Transposon Insertion in the hbdA Gene

    PubMed Central

    Fales, Linda; Kryszak, Luiza; Zeilstra-Ryalls, Jill

    2001-01-01

    The common precursor to all tetrapyrroles is 5-aminolevulinic acid (ALA), and in Rhodobacter sphaeroides its formation occurs via the Shemin pathway. ALA synthase activity is encoded by two differentially regulated genes in R. sphaeroides 2.4.1: hemA and hemT. In our investigations of hemA regulation, we applied transposon mutagenesis under aerobic conditions, followed by a selection that identified transposon insertion mutants in which hemA expression is elevated. One of these mutants has been characterized previously (J. Zeilstra-Ryalls and S. Kaplan, J. Bacteriol. 178:985–993, 1996), and here we describe our analysis of a second mutant strain. The transposon inserted into the coding sequences of hbdA, coding for S-(+)-β-hydroxybutyryl–coenzyme A dehydrogenase and catalyzing an NAD-dependent reaction. We provide evidence that the hbdA gene product participates in polyhydroxybutyrate (PHB) metabolism and, based on our findings, we discuss possibilities as to how defective PHB metabolism might alter the level of hemA expression. PMID:11160087

  6. UV-curable gels as topical nail medicines:In vivo residence, anti-fungal efficacy and influence of gel components on their properties.

    PubMed

    Kerai, L V; Hilton, S; Maugueret, M; Kazi, B B; Faull, J; Bhakta, S; Murdan, S

    2016-11-30

    UV-curable gels, used as nail cosmetics for their in vivo durability, were reported to be promising as topical nail medicines. Our first aim was thus to investigate whether such durability applies to drug-loaded formulations. This was found to be true. However, ethanol inclusion in the pharmaceutical formulation (to enable drug loading) reduced the in vivo residence. The second aim was therefore to determine any other effects of ethanol, and if ethanol could be avoided by the choice of monomers. Thus, three methacrylate monomers, ethyl methacrylate, isobornyl methacrylate and 2-hydroxyethyl methacrylate (HEMA) were selected, and their influence on the formulation properties were determined. Ethanol and the methacrylate monomer influenced some (but not all) of the formulation properties. The most significant was that HEMA could dissolve drug and enable the preparation of ethanol-free, drug-loaded formulations, which would benefit in vivo residence. The absence of ethanol reduced drug loading, release and ungual flux, but had no negative impact on the in vitro anti-fungal efficacy. Thus, judicious selection of gel components enabled the exclusion of ethanol. The long in vivo residence, little residual monomers, sufficient ungual permeation and in vitro anti-fungal activity of the gels indicates their potential as anti-onychomycotic topical medicines.

  7. Multifunctional poly(alkyl methacrylate) films for dental care.

    PubMed

    Nielsen, Birthe V; Nevell, Thomas G; Barbu, Eugen; Smith, James R; Rees, Gareth D; Tsibouklis, John

    2011-02-01

    Towards the evaluation of non-permanent dental coatings for their capacity to impart dental-care benefits, thin films of a homologous series of comb-like poly(alkyl methacrylate)s (ethyl to octadecyl) have been deposited, from aqueous latex formulations, onto dentally relevant substrates. AFM studies have shown that the thickness (40-300 nm) and surface roughness (8-12 nm) of coherent polymer films are influenced by the degree of polymerization and by the length of the pendant chain. Of the polymers under consideration, poly(butyl methacrylate) formed a close-packed film that conferred to dental substrates a high degree of inhibition to acid-mediated erosion (about 27%), as evaluated by released-phosphate determinations. The potential utility of the coatings to act as anti-sensitivity barriers has been evaluated by determining the hydraulic conductance of coated bovine-dentine substrates; single treatments of dentine discs with poly(butyl methacrylate) or with poly(ethyl methacrylate) effected mean respective reductions in fluid flow of about 23% with respect to water-treated controls; repeated applications of the poly(butyl methacrylate) latex led to mean reductions in fluid flow of about 80%. Chromometric measurements have shown that pellicle-coated hydroxyapatite discs treated with poly(butyl methacrylate), poly(hexyl methacrylate) or poly(lauryl methacrylate) exhibit significant resistance to staining by food chromogens.

  8. Zwitterionic Poly(amino acid methacrylate) Brushes

    PubMed Central

    2014-01-01

    A new cysteine-based methacrylic monomer (CysMA) was conveniently synthesized via selective thia-Michael addition of a commercially available methacrylate-acrylate precursor in aqueous solution without recourse to protecting group chemistry. Poly(cysteine methacrylate) (PCysMA) brushes were grown from the surface of silicon wafers by atom-transfer radical polymerization. Brush thicknesses of ca. 27 nm were achieved within 270 min at 20 °C. Each CysMA residue comprises a primary amine and a carboxylic acid. Surface zeta potential and atomic force microscopy (AFM) studies of the pH-responsive PCysMA brushes confirm that they are highly extended either below pH 2 or above pH 9.5, since they possess either cationic or anionic character, respectively. At intermediate pH, PCysMA brushes are zwitterionic. At physiological pH, they exhibit excellent resistance to biofouling and negligible cytotoxicity. PCysMA brushes undergo photodegradation: AFM topographical imaging indicates significant mass loss from the brush layer, while XPS studies confirm that exposure to UV radiation produces surface aldehyde sites that can be subsequently derivatized with amines. UV exposure using a photomask yielded sharp, well-defined micropatterned PCysMA brushes functionalized with aldehyde groups that enable conjugation to green fluorescent protein (GFP). Nanopatterned PCysMA brushes were obtained using interference lithography, and confocal microscopy again confirmed the selective conjugation of GFP. Finally, PCysMA undergoes complex base-catalyzed degradation in alkaline solution, leading to the elimination of several small molecules. However, good long-term chemical stability was observed when PCysMA brushes were immersed in aqueous solution at physiological pH. PMID:24884533

  9. Injectible bodily prosthetics employing methacrylic copolymer gels

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  10. Methacrylic resin having a high solar radiant energy absorbing property and process for producing the same

    SciTech Connect

    Abe, K.; Kamada, K.; Nakai, Y.

    1981-10-20

    A methacrylic resin having a high solar radiant energy absorbing property wherein an organic compound (A) containing cupric ion and a compound (B) having at least one p-o-h bond in a molecule are contained into the methacrylic resin selected from poly(Methyl methacrylate) or methacrylic polymers containing at least 50% by weight of a methyl methacrylate unit. A process for producing said methacrylic resin is also disclosed.

  11. DEGRADATION OF POLY(METHYL METHACRYLATE) IN SOLUTION

    EPA Science Inventory

    The rate of degradation of poly(methyl methacrylate) (PMMA) to methyl methacrylate (MMA) was investigated in the liquid phase with toluene as the solvent. The degradation experiments were carried out in a tubular flow reactor at 1000 psig (6.8 MPa) and at four different temperat...

  12. Uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide.

    PubMed

    Liu, Ze; Ge, Maofa; Wang, Weigang

    2012-01-01

    Multiphase acid-catalyzed oxidation by hydrogen peroxide has been suggested to be a potential route to secondary organic aerosol formation from isoprene and its gas-phase oxidation products, but the lack of kinetics data significantly limited the evaluation of this process in the atmosphere. Here we report the first measurement of the uptake of isoprene, methacrylic acid and methyl methacrylate into aqueous solutions of sulfuric acid and hydrogen peroxide. Isoprene cannot readily partition into the solution because of its high volatility and low solubility, which hinders its further liquid-phase oxidation. Both methacrylic acid and methyl methacrylate can enter the solutions and be oxidized by hydrogen peroxide, and steady-state uptake was observed with the acidity of solution above 30 wt.% and 70 wt.%, respectively. The steady-state uptake coefficient of methacrylic acid is much larger than that of methyl methacrylate for a solution with same acidity. These observations can be explained by the different reactivity of these two compounds caused by the different electron-withdrawing conjugation between carboxyl and ester groups. The atmospheric lifetimes were estimated based on the calculated steady-state uptake coefficients. These results demonstrate that the multiphase acid-catalyzed oxidation of methacrylic acid plays a role in secondary organic aerosol formation, but for isoprene and methyl methacrylate, this process is not important in the troposphere.

  13. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules.

    PubMed

    Romano, Ariel A; Hahn, Tobias; Davis, Nicole; Lowery, Colin A; Struss, Anjali K; Janda, Kim D; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

    2012-02-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C(12)-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding.

  14. The Fe(III) and Ga(III) coordination chemistry of 3-(1-hydroxymethylidene) and 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione: Novel tetramic acid degradation products of homoserine lactone bacterial quorum sensing molecules

    PubMed Central

    Romano, Ariel A.; Hahn, Tobias; Davis, Nicole; Lowery, Colin A.; Struss, Anjali K.; Janda, Kim D.; Böttger, Lars H.; Matzanke, Berthold F.; Carrano, Carl J.

    2011-01-01

    Bacteria use small diffusible molecules to exchange information in a process called quorum sensing (QS). An important class of quorum sensing molecules used by Gram-negative bacteria is the family of N-acylhomoserine lactones (HSL). It was recently discovered that a degradation product of the QS molecule 3-oxo-C12-homoserine lactone, the tetramic acid 3-(1-hydroxydecylidene)-5-(2-hydroxyethyl)pyrrolidine-2,4-dione, is a potent antibacterial agent, thus implying roles for QS outside of simply communication. Because these tetramic acids also appear to bind iron with appreciable affinity it was suggested that metal binding might contribute to their biological activity. Here, using a variety of spectroscopic tools, we describe the coordination chemistry of both the methylidene and decylidene tetramic acid derivatives with Fe(III) and Ga(III) and discuss the potential biological significance of such metal binding. PMID:22178671

  15. FUNCTIONALIZED, SWELLABLE HYDROGEL LAYERS AS A PLATFORM FOR CELL STUDIES

    PubMed Central

    Marí-Buyé, Núria; O'Shaughnessy, Shannan; Colominas, Carles; Semino, Carlos E.; Gleason, Karen K.; Borrós, Salvador

    2014-01-01

    This paper reports the design, synthesis and characterization of thin films as a platform for studying the separate influences of physical and chemical cues of a matrix on the adhesion, growth and final phenotype of cells. Independent control of the physical and chemical properties of functionalized, swellable hydrogel thin films was achieved using initiated Chemical Vapor Deposition (iCVD). The systematic variation in crosslink density is demonstrated to control the swelling ability of the iCVD hydrogel films based on 2-hydroxyethyl methacrylate (HEMA). At the same time, the incorporation of controllable concentrations of the active ester pentafluorophenyl methacrylate (PFM) allows easy immobilization of aminated bioactive motifs, such as bioactive peptides. Initial cell culture results with Human Umbilical Vein Endothelial Cells (HUVEC) indicated that the strategy of using PFM to immobilize a cell-adhesion peptide motif onto the hydrogel layers promotes proper HUVEC growth and enhances their phenotype. PMID:25414625

  16. Polyethylenimine-immobilized core-shell nanoparticles: synthesis, characterization, and biocompatibility test.

    PubMed

    Ratanajanchai, Montri; Soodvilai, Sunhapas; Pimpha, Nuttaporn; Sunintaboon, Panya

    2014-01-01

    Herein, we prepared PEI-immobilized core-shell particles possessing various types of polymer cores via a visible light-induced surfactant-free emulsion polymerization (SFEP) of three vinyl monomers: styrene (St), methyl methacrylate (MMA), and 2-hydroxyethyl methacrylate (HEMA). An effect of monomers on the polymerization and characteristics of resulting products was investigated. Monomers with high polarity can provide high monomer conversion, high percentage of grafted PEI, stable particles with uniform size distribution but less amino groups per particles. All prepared nanoparticles exhibited a core-shell nanostructure, containing PEI on the shell with hydrodynamic size around 140-230nm. For in-vitro study in Caco-2 cells, we found that the incorporation of PEI into these core-shell nanoparticles can significantly reduce its cytotoxic effect and also be able to internalized within the cells. Accordingly, these biocompatible particles would be useful for various biomedical applications, including gene transfection and intracellular drug delivery.

  17. Improvement of holographic thermal stability in phenanthrenequinone-doped poly(methyl methacrylate-co-methacrylic acid) photopolymer

    NASA Astrophysics Data System (ADS)

    Yu, Dan; Liu, Hongpeng; Wang, Heng; Wang, Jian; Jiang, Yongyuan; Sun, Xiudong

    2011-08-01

    Experimental studies of holographic thermal stability in phenanthrenequinone (PQ)-doped poly(methyl methacrylate-co-methacrylic acid) [P(MMA-co-MAA)] photopolymers are presented. A possibility to improve the thermal stability of holograms is demonstrated by doping methacrylic acid (MAA) into the poly(methyl methacrylate) (PMMA) polymer matrix. MAA as a copolymerization monomer can form a more stable polymer matrix with methyl methacrylate (MMA) monomer and increase average molecular weight of photoproducts, which finally depress the diffusion of photoproduct. The optimized MAA concentration copolymerized into P(MMA-co-MAA) polymer matrix can bring nearly a month's lifetime of gratings, which is obviously an improvement over the usual PQ-PMMA material under thermal treatment.

  18. Investigation of flexural strength and cytotoxicity of acrylic resin copolymers by using different polymerization methods

    PubMed Central

    Ozdemir, Ali Kemal; Turgut, Mehmet; Boztug, Ali; Sumer, Zeynep

    2015-01-01

    PURPOSE The aim of this study was to appraise the some mechanical properties of polymethyl methacrylate based denture base resin polymerized by copolymerization mechanism, and to investigate the cytotoxic effect of these copolymer resins. MATERIALS AND METHODS 2-hydroxyethyl methacrylate (HEMA) and isobutyl methacrylate (IBMA) were added to monomers of conventional heat polymerized and injection-molded poly methyl methacrylate (PMMA) resin contents of 2%, 3%, and 5% by volume and polymerization was carried out. Three-point bending test was performed to detect flexural strength and the elasticity modulus of the resins. To determine the statistical differences between the study groups, the Kruskall-Wallis test was performed. Then pairwise comparisons were performed between significant groups by Mann-Whitney U test. Agar-overlay test was performed to determine cytotoxic effect of copolymer resins. Chemical analysis was determined by FTIR spectrum. RESULTS Synthesis of the copolymer was approved by FTIR spectroscopy. Within the conventional heat-polymerized group maximum transverse strength had been seen in the HEMA 2% concentration; however, when the concentration ratio increased, the strength decreased. In the injection-molded group, maximum transverse strength had been seen in the IBMA 2% concentration; also as the concentration ratio increased, the strength decreased. Only IBMA showed no cytotoxic effect at low concentrations when both two polymerization methods applied while HEMA showed cytotoxic effect in the injection-molded resins. CONCLUSION Within the limitations of this study, it may be concluded that IBMA and HEMA may be used in low concentration and at high temperature to obtain non-cytotoxic and durable copolymer structure. PMID:25932307

  19. Studies on novel radiopaque methyl methacrylate: glycidyl methacrylate based polymer for biomedical applications.

    PubMed

    Dawlee, S; Jayakrishnan, A; Jayabalan, M

    2009-12-01

    A new class of radiopaque copolymer using methyl methacrylate (MMA) and glycidyl methacrylate (GMA) monomers was synthesized and characterized. The copolymer was made radiopaque by the epoxide ring opening of GMA using the catalyst o-phenylenediamine and the subsequent covalent attachment of elemental iodine. The copolymer was characterized by Fourier transform infrared (FTIR) spectra, energy dispersive X-ray analysis using environmental scanning electron microscope (EDAX), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). X-ray visibility of the copolymer was checked by X-radiography. Blood compatibility and cytotoxicity of the newly synthesized copolymer were also evaluated. The iodinated copolymer was thermally stable, blood compatible, non-cytotoxic, and highly radiopaque. The presence of bulky iodine group created a new copolymer with modified properties for potential use in biomedical applications.

  20. Poly (hydroxyethyl methacrylate-glycidyl methacrylate) films modified with different functional groups: In vitro interactions with platelets and rat stem cells.

    PubMed

    Bayramoglu, Gulay; Bitirim, Verda; Tunali, Yagmur; Arica, Mehmet Yakup; Akcali, Kamil Can

    2013-03-01

    Copolymerization of 2-hydroxyethylmethacrylate (HEMA) with glycidylmethacrylate (GMA) in the presence of α-α'-azoisobisbutyronitrile (AIBN) resulted in the formation of hydrogel films carrying reactive epoxy groups. Thirteen kinds of different molecules with pendant NH2 group were used for modifications of the p(HEMA-GMA) films. The NH2 group served as anchor binding site for immobilization of functional groups on the hydrogel film via direct epoxy ring opening reaction. The modified hydrogel films were characterized by FTIR, and contact angle studies. In addition, mechanical properties of the hydrogel films were studied, and modified hydrogel films showed improved mechanical properties compared with the non-modified film, but they are less elastic than the non-modified film. The biological activities of these films such as platelet adhesion, red blood cells hemolysis, and swelling behavior were studied. The effect of modified hydrogel films, including NH2, (using different aliphatic CH2 chain lengths) CH3, SO3H, aromatic groups with substituted OH and COOH groups, and amino acids were also investigated on the adhesion, morphology and survival of rat mesenchymal stem cells (MSCs). The MTT colorimetric assay reveals that the p(HEMA-GMA)-GA-AB, p(HEMA-GMA)-GA-Phe, p(HEMA-GMA)-GA-Trp, p(HEMA-GMA)-GA-Glu formulations have an excellent biocompatibility to promote the cell adhesion and growth. We anticipate that the fabricated p(HEMA-GMA) based hydrogel films with controllable surface chemistry and good stable swelling ratio may find extensive applications in future development of tissue engineering scaffold materials, and in various biotechnological areas.

  1. Time-resolved thermal lens study on the heat dissipation effects in solid polymeric matrices used as laser dyes

    NASA Astrophysics Data System (ADS)

    Pons, M.; Nonell, S.; García-Moreno, I.; Costela, Á.; Sastre, R.

    A dual-beam pulsed-laser time-resolved thermal lens (TRTL) has been used to study the heat dissipation effects in solid polymers employed as laser dyes. The laser-dye samples studied are polymer solutions of rhodamine 6G (Rh6G), namely homopolymers of methyl methacrylate (MMA) and copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate (HEMA) with MMA:HEMA compositions 1:1 and 7:3 vol./vol., where the dye is either dissolved or modified and copolymerized with methacrylate monomers. The long-term stability of the laser material is independent of the thermal diffusivity of the samples, as determined by the TRTL technique. This suggests that the rate of heat dissipation does not play a major role in the photostability of the samples. In contrast, the TRTL experiments have revealed permanent changes in the optical properties of the polymers when subjected to a large number of laser pulses. This is explained in terms of permanent plastic deformation of the matrices.

  2. Contribution of the comonomers to the bulk and surface properties of methacrylate copolymers.

    PubMed

    Hermitte, L; Thomas, F; Bougaran, R; Martelet, C

    2004-04-01

    Relationships between formulation, bulk properties, and surface properties are investigated on series of copolymers prepared with hydroxyethylmethacrylate (HEMA), methylmethacrylate (MMA), and ethylmethacrylate (EMA) monomers, and on the homopolymers PMMA and PHEMA. The bulk water content, swelling ratio, and static (sessile drop and captive bubble) and dynamic (Wilhelmy plate technique) contact angles and the electrokinetic potential (streaming potential) are measured. The bulk water content and swelling ratio of HEMA copolymers are proportional to the amount of HEMA and are linearly correlated to the contact angle hysteresis. Periodic instabilities in the wetting cycles, similar to Haines jumps, are observed with HEMA copolymers and support a bidirectional relaxation of the hydrophilic groups respectively towards external water and capillary water. The origin of the electrokinetic potential of these nonionizable polymers is attributed to specific adsorption of [Formula: see text] ions. Its dependence on surface hydrophobicity and statistical length of the side-chains is interpreted in terms of the properties of water molecules near the interface.

  3. Properties of Ultra-Violet Cured Poly(diemthylsiloxane)-Urea Acrylates.

    DTIC Science & Technology

    1984-11-01

    polycaprolactone) and polyol molecular weight on physical properties were evaluated. TDI/ hydroxyethyl methacrylate ( HEMA ) based samples were also...diluents. The reactive diluents or crosslinkers I. chosen were: ethyl methacrylate (EMA), hydroxyethyl methacrylate ( HEMA ), butyl acrylate (BA...butylacrylate (BA), acrylic acid (AA), ethyl methacrylate (EMA), B- hydroxyethyl ’metthacrylate ( HEMA ), m~ethyl trethacrylate (MMA), and 4-vinylpyridine (4

  4. Novel injectable biomimetic hydrogels with carbon nanofibers and self assembled rosette nanotubes for myocardial applications.

    PubMed

    Meng, Xiangling; Stout, David A; Sun, Linlin; Beingessner, Rachel L; Fenniri, Hicham; Webster, Thomas J

    2013-04-01

    The objective of the present in vitro study was to investigate cardiomyocyte functions, specifically their adhesion and proliferation, on injectable scaffolds containing RNT (rosette nanotubes) and CNF (carbon nanofibers) in a pHEMA (poly(2-hydroxyethyl methacrylate)) hydrogel to determine their potential for myocardial tissue engineering applications. RNTs are novel biocompatible nanomaterials assembled from synthetic analogs of DNA bases guanine and cytosine that self-assemble within minutes when placed in aqueous solutions at body temperatures. These materials could potentially improve cardiomyocyte functions and solidification time of pHEMA and CNF composites. Because heart tissue is conductive, CNFs were added to pHEMA to increase the composite's conductivity. Our results showed that cardiomyocyte density increased after 4 h, 1 day, and 3 days with greater amounts of CNFs and greater amounts of RNTs in pHEMA (up to 10 mg mL(-1) CNFs and 0.05 mg mL(-1) RNTs). Factors that may have increased cardiomyocyte functions include greater wettability, conductivity, and an increase in surface nanoroughness with greater amounts of CNFs and RNTs. In effect, contact angles measured on the surface of the composites decreased while the conductivity and surface roughness increased as CNFs and RNTs content increased. Lastly, the ultimate tensile modulus decreased for composites with greater amounts of CNFs. In summary, the properties of these injectable composites make them promising candidates for myocardial tissue engineering applications and should be further studied.

  5. Characterization of biomaterials polar interactions in physiological conditions using liquid-liquid contact angle measurements: relation to fibronectin adsorption.

    PubMed

    Velzenberger, Elodie; El Kirat, Karim; Legeay, Gilbert; Nagel, Marie-Danielle; Pezron, Isabelle

    2009-02-01

    Wettability of biomaterials surfaces and protein-coated substrates is generally characterized with the sessile drop technique using polar and apolar liquids. This procedure is often performed in air, which does not reflect the physiological conditions. In this study, liquid/liquid contact angle measurements were carried out to be closer to cell culture conditions. This technique allowed us to evaluate the polar contribution to the work of adhesion between an aqueous medium and four selected biomaterials widely used in tissue culture applications: bacteriological grade polystyrene (PS), tissue culture polystyrene (tPS), poly(2-hydroxyethyl methacrylate) film (PolyHEMA), and hydroxypropylmethylcellulose-carboxymethylcellulose bi-layered Petri dish (CEL). The contributions of polar interactions were also estimated on the same biomaterials after fibronectin (Fn) adsorption. The quantity of Fn adsorbed on PS, tPS, PolyHEMA and CEL surfaces was evaluated by using the fluorescein-labeled protein. PolyHEMA and CEL were found to be hydrophilic, tPS was moderately hydrophilic and PS was highly hydrophobic. After Fn adsorption on PS and tPS, a significant increase of the surface polar interaction was observed. On PolyHEMA and CEL, no significant adsorption of Fn was detected and the polar interactions remained unchanged. Finally, an inverse correlation between the polarity of the surfaces and the quantity of adsorbed Fn was established.

  6. Nonthrombogenic polymer vascular prosthesis.

    PubMed

    Nojiri, C; Senshu, K; Okano, T

    1995-01-01

    Although many synthetic vascular grafts have been developed and evaluated experimentally or clinically, none of them have met long-term patency when applied as a small diameter vascular substitute. We have recently developed a small caliber vascular graft (3 mm i.d.) using a nonthrombogenic polymer coating. The graft consists of three layered structures: Dacron for the outer layer, polyurethane in the middle layer, and a HEMA/styrene block copolymer (HEMA-st) coating for the inner layer. HEMA-st is an amphiphilic block copolymer composed of 2-hydroxyethyl methacrylate and styrene which has demonstrated improved blood compatibility over existing biomedical polymers in both in vitro and ex vivo experiments. Ten grafts were evaluated in a dog bilateral carotid replacement model. The grafts were electively retrieved at 7, 14, 30, 92, and 372 days after implantation. All grafts were patent without detectable thrombi along the graft length including anastomotic sites. Scanning electron micrographs of retrieved graft lumen showed fairly clean surfaces covered with a homogenous protein-like layer without microthrombi or endothelial cell lining. The thickness of the surface protein layer measured by a transmission electron microscopy was what can be described as monolayer protein adsorption regardless of implantation periods of as much as 372 days. A stable monolayer adsorbed protein layer formed on HEMA-st surfaces demonstrated nonthrombogenic activities in vivo and secure long-term patency of small caliber vascular grafts with the absence of an endothelial cell lining.

  7. A Tailor-Made Synthetic Polymer for Cell Encapsulation: Design Rationale, Synthesis, Chemical-Physics and Biological Characterizations.

    PubMed

    Gerges, Irini; Tamplenizza, Margherita; Rossi, Eleonora; Tocchio, Alessandro; Martello, Federico; Recordati, Camilla; Kumar, Deepak; Forsyth, Nicholas R; Liu, Yang; Lenardi, Cristina

    2016-06-01

    This study presents a custom-made in situ gelling polymeric precursor for cell encapsulation. Composed of poly((2-hydroxyethyl)methacrylate-co-(3-aminopropyl)methacrylamide) (P(HEMA-co-APM) mother backbone and RGD-mimicking poly(amidoamine) (PAA) moiteis, the comb-like structured polymeric precursor is tailored to gather the advantages of the two families of synthetic polymers, i.e., the good mechanical integrity of PHEMA-based polymers and the biocompatibility and biodegradability of PAAs. The role of P(HEMA-co-APM) in the regulation of the chemico-physical properties of P(HEMA-co-APM)/PAA hydrogels is thoroughly investigated. On the basis of obtained results, namely the capability of maintaining vital NIH3T3 cell line in vitro for 2 d in a 3D cell culture, the in vivo biocompatibility in murine model for 16 d, and the ability of finely tuning mechanical properties and degradation kinetics, it can be assessed that P(HEMA-co-APM)/PAAs offer a cost-effective valid alternative to the so far studied natural polymer-based systems for cell encapsulation.

  8. Phenylalanine containing hydrophobic nanospheres for antibody purification.

    PubMed

    Türkmen, Deniz; Denizli, Adil; Oztürk, Nevra; Akgöl, Sinan; Elkak, Assem

    2008-01-01

    In this study, novel hydrophobic nanospheres with an average size of 158 nm utilizing N-methacryloyl-(L)-phenylalanine methyl ester (MAPA) as a hydrophobic monomer were produced by surfactant free emulsion polymerization of 2-hydroxyethyl methacrylate (HEMA) and MAPA conducted in an aqueous dispersion medium. MAPA was synthesized using methacryloyl chloride and L-phenylalanine methyl ester. Specific surface area of the nonporous nanospheres was found to be 1874 m2/g. Poly(HEMA-MAPA) nanospheres were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Average particle size, size distribution, and surface charge measurements were also performed. Elemental analysis of MAPA for nitrogen was estimated as 0.42 mmol/g polymer. Then, poly(HEMA-MAPA) nanospheres were used in the adsorption of immunoglobulin G (IgG) in batch system. Higher adsorption values (780 mg/g) were obtained when the poly (HEMA-MAPA) nanospheres were used from both aqueous solutions and human plasma. The adsorption phenomena appeared to follow a typical Langmuir isotherm. It was observed that IgG could be repeatedly adsorbed and desorbed without significant loss in adsorption amount. These findings show considerable promise for this material as a hydrophobic support in industrial processes.

  9. Enhanced Bioactivity of α-Tocopheryl Succinate Based Block Copolymer Nanoparticles by Reduced Hydrophobicity.

    PubMed

    Palao-Suay, Raquel; Aguilar, María Rosa; Parra-Ruiz, Francisco J; Maji, Samarendra; Hoogenboom, Richard; Rohner, Nathan A; Thomas, Susan N; Román, Julio San

    2016-12-01

    Well-structured amphiphilic copolymers are necessary to obtain self-assembled nanoparticles (NPs) based on synthetic polymers. Highly homogeneous and monodispersed macromolecules obtained by controlled polymerization have successfully been used for this purpose. However, disaggregation of the organized macromolecules is desired when a bioactive element, such as α-tocopheryl succinate, is introduced in self-assembled NPs and this element must be exposed or released to exert its action. The aim of this work is to demonstrate that the bioactivity of synthetic NPs based on defined reversible addition-fragmentation chain transfer polymerization copolymers can be enhanced by the introduction of hydrophilic comonomers in the hydrophobic segment. The amphiphilic terpolymers are based on poly(ethylene glycol) (PEG) as hydrophilic block, and a hydrophobic block based on a methacrylic derivative of α-tocopheryl succinate (MTOS) and small amounts of 2-hydroxyethyl methacrylate (HEMA) (PEG-b-poly(MTOS-co-HEMA)). The introduction of HEMA reduces hydrophobicity and introduces "disorder" both in the homogeneous blocks and the compact core of the corresponding NPs. These NPs are able to encapsulate additional α-tocopheryl succinate (α-TOS) with high efficiency and their biological activity is much higher than that described for the unmodified copolymers, proposedly due to more efficient degradation and release of α-TOS, demonstrating the importance of the hydrophilic-hydrophobic balance.

  10. Environment effects on the lasing photostability of Rhodamine 6G incorporated into organic-inorganic hybrid materials

    NASA Astrophysics Data System (ADS)

    Costela, A.; García-Moreno, I.; Gómez, C.; García, O.; Sastre, R.

    The effect on the lasing photostability of Rhodamine 6G (Rh6G), and the rigidity of a hybrid inorganic-organic matrix by controlled addition of di-, tri- and tetrafunctionalized alkoxides has been evaluated. The dye was incorporated into hybrid matrices of (2-hydroxyethyl methacrylate) (HEMA) or vol/vol copolymers of methyl methacrylate (MMA) and HEMA with different weight proportions of polycondensated dimethyldiethoxysilane (DEOS), methyltriethoxysilane (TRIEOS), and tetraethoxysilane (TEOS). The laser samples were transversaly pumped at 534 nm at 5.5 mJ/pulse and up to a 10 Hz repetition rate. The dependence of the laser photostability on organic-inorganic composition, pH of the medium, and thermal treatment of the samples was studied. Good stability, with a drop of the initial laser output of only 13% after 10000 pump pulses at 10 Hz in a thermally postcured (HEMA-15 wt%TRIEOS) matrix was obtained. Careful control of the synthesis process is required to reach the necessary photostability for a solid-state dye laser based on hybrid matrices to become competitive with liquid dye lasers.

  11. Radiation effect on polyesters

    NASA Astrophysics Data System (ADS)

    Mitomo, Hiroshi; Watanabe, Yuhei; Yoshii, Fumio; Makuuchi, Keizo

    1995-08-01

    Poly(3-hydroxybutyrate)(PHB) and its copolymer poly(3-hydroxybutyrate-3-hydroxyvalerate) [P(HB-HV)] were irradiated with γ-rays in air or vacuum. Polymer chain scission occurred and resulted in depression of melting points ( Tm), glass-transition temperatures ( Tg) and number-average molecular weight ( overlineMn). Decrease in overlineMn of the sample irradiated in vacuum was smaller than that irradiated in air, implying introduction of crosslinking. The Tm and Tg of samples irradiated in air were inversely proportional to overlineMn. Their biodegradability was clearly promoted with decreasing overlineMn. Radiation grafting of methyl methacrylate (MMA) or 2-hydroxyethyl methacrylate (HEMA) was carried out by in-source polymerization. Degree of grafting ( Xg) increased as irradiation dose increased and leveled off around 5 kGy. The Xg of PHB grafted was lower than that of P(HB-HV) because of higher crystallinity of the former. Crosslinking between the grafted PMMA chains was easily formed. Biodegradability of both polymers steeply decreased by introduction of MMA grafting, while that of polymers grafted with HEMA increased at first because of improvement of wettability then steeply decreased with increasing Xg of HEMA.

  12. Analysis of the effect modification of the photoinitiator system in pyrromethene-HEMA based photopolymerizable holographic recording materials

    NASA Astrophysics Data System (ADS)

    Blaya, S.; Acebal, P.; Carretero, L.; Madrigal, R. F.; Murciano, A.; Fimia, A.

    2011-06-01

    The aim of this work is to analyze the effect of the addition or substitution of several components (coinitiator and photoinitiator) in a photopolymerizable holographic material based on a pyrromethene dye (PM567) acting as a photoinitiator and HEMA as monomer both of them dissolved in a dry polymeric matrix of PMMA. For this, diffraction gratings were recorded at different intensities and the energetic evolution of the diffraction efficiency as well as the observed inhibition period were studied as a function of the component that has been modified (coinitiator (tert-butyl peroxybenzoate (tBPH)) or photoinitiator PM546 and PM556). Moreover, the experimental angular selectivity curves were theoretically analyzed by the model of Kubota and Uchida, and as a result information such as the effective thickness, fringe bending and non-uniform index modulation against the thickness of grating was obtained. It is observed that when PM546 is used instead of PM567, better responses for a wide range of intensities are obtained, in particular at high intensity where gratings with low fringe bending and a relative constant index modulation against thickness is reached. When a coinitiator such as tert-butyl peroxybenzoate (tBPH) is added to the reference composition, shorter inhibition periods are obtained with low fringe bending but with lower diffraction efficiencies.

  13. pHEMA Encapsulated PEDOT-PSS-CNT Microsphere Microelectrodes for Recording Single Unit Activity in the Brain

    PubMed Central

    Castagnola, Elisa; Maggiolini, Emma; Ceseracciu, Luca; Ciarpella, Francesca; Zucchini, Elena; De Faveri, Sara; Fadiga, Luciano; Ricci, Davide

    2016-01-01

    The long-term reliability of neural interfaces and stability of high-quality recordings are still unsolved issues in neuroscience research. High surface area PEDOT-PSS-CNT composites are able to greatly improve the performance of recording and stimulation for traditional intracortical metal microelectrodes by decreasing their impedance and increasing their charge transfer capability. This enhancement significantly reduces the size of the implantable device though preserving excellent electrical performances. On the other hand, the presence of nanomaterials often rises concerns regarding possible health hazards, especially when considering a clinical application of the devices. For this reason, we decided to explore the problem from a new perspective by designing and testing an innovative device based on nanostructured microspheres grown on a thin tether, integrating PEDOT-PSS-CNT nanocomposites with a soft synthetic permanent biocompatible hydrogel. The pHEMA hydrogel preserves the electrochemical performance and high quality recording ability of PEDOT-PSS-CNT coated devices, reduces the mechanical mismatch between soft brain tissue and stiff devices and also avoids direct contact between the neural tissue and the nanocomposite, by acting as a biocompatible protective barrier against potential nanomaterial detachment. Moreover, the spherical shape of the electrode together with the surface area increase provided by the nanocomposite deposited on it, maximize the electrical contact and may improve recording stability over time. These results have a good potential to contribute to fulfill the grand challenge of obtaining stable neural interfaces for long-term applications. PMID:27147944

  14. Quaternary ammonium poly(diethylaminoethyl methacrylate) possessing antimicrobial activity.

    PubMed

    Farah, Shady; Aviv, Oren; Laout, Natalia; Ratner, Stanislav; Beyth, Nurit; Domb, Abraham J

    2015-04-01

    Quaternary ammonium (QA) methacrylate monomers and polymers were synthesized from a N-alkylation of N,N-diethylaminoethyl methacrylate (DEAEM) monomer. Linear copolymers, and for the first time reported crosslinked nanoparticles (NPs), based QA-PDEAEM were prepared by radical polymerization of the quaternized QA-DEAEM monomers with either methyl methacrylate (MMA) or a divinyl monomer. QA-PDEAEM NPs of 50-70 nm were embedded in polyethylene vinyl acetate coating. QA-polymers with N-C8 and N-C18 alkyl chains and copolymers with methyl methacrylate were prepared at different molar ratios and examined for their antimicrobial effectiveness. These coatings exhibited strong antibacterial activity against four representative Gram-positive and Gram-negative bacteria.

  15. Photocurable bioactive bone cement based on hydroxyethyl methacrylate-poly(acrylic/maleic) acid resin and mesoporous sol gel-derived bioactive glass.

    PubMed

    Hesaraki, S

    2016-06-01

    This paper reports on strong and bioactive bone cement based on ternary bioactive SiO2-CaO-P2O5 glass particles and a photocurable resin comprising hydroxyethyl methacrylate (HEMA) and poly(acrylic/maleic) acid. The as-cured composite represented a compressive strength of about 95 MPa but it weakened during soaking in simulated body fluid, SBF, qua its compressive strength reached to about 20 MPa after immersing for 30 days. Biodegradability of the composite was confirmed by reducing its initial weight (~32%) as well as decreasing the molecular weight of early cured resin during the soaking procedure. The composite exhibited in vitro calcium phosphate precipitation in the form of nanosized carbonated hydroxyapatite, which indicates its bone bonding ability. Proliferation of calvarium-derived newborn rat osteoblasts seeded on top of the composite was observed during incubation at 37 °C, meanwhile, an adequate cell supporting ability was found. Consequently, it seems that the produced composite is an appropriate alternative for bone defect injuries, because of its good cell responses, high compressive strength and ongoing biodegradability, though more in vivo experiments are essential to confirm this assumption.

  16. Thermally Switchable Thin Films of an ABC Triblock Copolymer of Poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate)

    SciTech Connect

    Zhang, Shanju; Liu, Zhan; Bucknall, David G.; He, Lihong; Hong, Kunlun; Mays, Jimmy; Allen, Mark

    2011-01-01

    The thermo-responsive behavior of polymer films consisting of novel linear triblock copolymers of poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBuMA-PMMA-P2FEMA) are reported using differential scanning calorimetry (DSC), atomic forcing microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contacting angle (CA) measurements. The surface morphology, wettability and chemical structure of thin films of these triblock copolymers on silicon wafers as a function of temperature have been investigated. It has been shown that the wettability of the films is thermally switchable. Detailed structural analysis shows that thermo-responsive surface composition changes are produced. The underlying mechanism of the thermoresponsive behavior is discussed.

  17. Thermally switchable thin films of an ABC triblock copolymer of poly( n -butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Zhang, Shanju; Liu, Zhan; Bucknall, David G.; He, Lihong; Hong, Kunlun; Mays, Jimmy W.; Allen, Mark G.

    2011-09-01

    The thermo-responsive behavior of polymer films consisting of novel linear triblock copolymers of poly( n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBuMA-PMMA-P2FEMA) are reported using differential scanning calorimetry (DSC), atomic forcing microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contacting angle (CA) measurements. The surface morphology, wettability and chemical structure of thin films of these triblock copolymers on silicon wafers as a function of temperature have been investigated. It has been shown that the wettability of the films is thermally switchable. Detailed structural analysis shows that thermo-responsive surface composition changes are produced. The underlying mechanism of the thermoresponsive behavior is discussed.

  18. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-09-08

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation.

  19. Effect of ethyl-alpha-hydroxymethylacrylate on selected properties of copolymers and ACP resin composites.

    PubMed

    Antonucci, Joseph M; Fowler, Bruce O; Weir, Michael D; Skrtic, Drago; Stansbury, Jeffrey W

    2008-10-01

    There is an increased interest in the development of bioactive polymeric dental composites and related materials that have potential for mineralized tissue regeneration and preservation. This study explores how the substitution of ethyl alpha-hydroxymethylacryate (EHMA) for 2-hydroxyethyl methacrylate (HEMA) in photo-activated 2,2-bis[p-(2'-hydroxy-3'-methacryloxypropoxy)phenyl]propane (Bis-GMA) and Bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) resins affected selected physicochemical properties of the polymers and their amorphous calcium phosphate (ACP) composites. Rate of polymerization and the degree of conversion (DC) of polymers {EHMA (E), HEMA (H), Bis-GMA/EHMA (BE), Bis-GMA/HEMA (BH), Bis-GMA/TEGDMA/EHMA (BTE) and Bis-GMA/TEGDMA/HEMA (BTH)} were assessed by photo-differential scanning calorimetry and Fourier-Transform Infrared (FTIR) spectroscopy. ACP/BTE and ACP/BTH composites were evaluated for DC, biaxial flexure strength (BFS), water sorption (WS) and mineral ion release. Mid-FTIR and near-IR measurements revealed the following order of decreasing DC: [E, H polymers (97.0%)] > [BE copolymer (89.9%)] > [BH copolymer (86.2%)] > [BTE, BTH copolymers (85.5%)] > [ACP/BTH composite (82.6%)] > [ACP/BTE composite (79.3%)]. Compared to HEMA, EHMA did not adversely affect the BFS of its copolymers and/or ACP composites. Lower WS of BTE copolymers and composites (28% and 14%, respectively, compared to the BTH copolymers and composites) only marginal reduced the ion release from ACP/BTE composites compared to ACP/BTH composites. More hydrophobic ACP composites with acceptable ion-releasing properties were developed by substituting the less hydrophilic EHMA for HEMA.

  20. New 3-D microarray platform based on macroporous polymer monoliths.

    PubMed

    Rober, M; Walter, J; Vlakh, E; Stahl, F; Kasper, C; Tennikova, T

    2009-06-30

    Polymer macroporous monoliths are widely used as efficient sorbents in different, mostly dynamic, interphase processes. In this paper, monolithic materials strongly bound to the inert glass surface are suggested as operative matrices at the development of three-dimensional (3-D) microarrays. For this purpose, several rigid macroporous copolymers differed by reactivity and hydrophobic-hydrophilic properties were synthesized and tested: (1) glycidyl methacrylate-co-ethylene dimethacrylate (poly(GMA-co-EDMA)), (2) glycidyl methacrylate-co-glycerol dimethacrylate (poly(GMA-co-GDMA)), (3) N-hydroxyphthalimide ester of acrylic acid-co-glycidyl methacrylate-co-ethylene dimethacrylate (poly(HPIEAA-co-GMA-co-EDMA)), (4) 2-cyanoethyl methacrylate-co-ethylene dimethacrylate (poly(CEMA-co-EDMA)), and (5) 2-cyanoethyl methacrylate-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate (poly(CEMA-co-HEMA-co-EDMA)). The constructed devices were used as platforms for protein microarrays construction and model mouse IgG-goat anti-mouse IgG affinity pair was used to demonstrate the potential of developed test-systems, as well as to optimize microanalytical conditions. The offered microarray platforms were applied to detect the bone tissue marker osteopontin directly in cell culture medium.

  1. Sequence dependent conformations of glycidyl methacrylate/butyl methacrylate copolymers in the gas phase

    NASA Astrophysics Data System (ADS)

    Baker, Erin Shammel; Gidden, Jennifer; Simonsick, William J.; Grady, Michael C.; Bowers, Michael T.

    2004-11-01

    Sequence dependent conformations of a series of glycidyl methacrylate/butyl methacrylate (GMA/BMA) copolymers cationized by sodium were analyzed in the gas phase using ion mobility methods. GMA and BMA have the same nominal mass but vary in exact mass by 0.036 Da (CH4 versus O). Matrix assisted laser desorption/ionization (MALDI) was used to form Na+(GMA/BMA) copolymer ions and their collision cross-sections were measured in helium using ion mobility methods. The copolymer sequences from Na+(GMA/BMA)3 to Na+(GMA/BMA)5 (i.e. for the trimer to the pentamer) were studied. Analysis by molecular mechanics/dynamics indicates that each copolymer (regardless of sequence) forms a ring around the sodium ions due to Na+/oxygen electrostatic interactions. However, the structures vary in size, since the epoxy oxygen atoms in the glycidyl groups are attracted to the sodium ions while the carbon-composed butyl groups are not. This allows copolymers with more GMA segments to fold tighter (more spherically) around the sodium ion and have smaller cross-sections than copolymers with a larger amount of BMA segments in the sequence. Due to this cross-sectional difference, the GMA/BMA sequence compositions of the trimer and tetramer could be quantified.

  2. Characterization of new acrylic bone cement based on methyl methacrylate/1-hydroxypropyl methacrylate monomer.

    PubMed

    Pascual, B; Goñi, I; Gurruchaga, M

    1999-01-01

    New formulations of acrylic bone cement based on methyl methacrylate/1-hydroxypropyl methacrylate (MMA/HPMA) monomers were developed with the purpose of obtaining more ductile materials with reduced polymerization shrinkage. In this way, the ductility of such materials increased, but the introduction of high percentages of the hydrophilic component produced an important decrease in Young's modulus and strength. To ascertain the reason for the deterioration of the tensile parameters, an analysis by scanning electron microscopy of these formulations was carried out; it revealed poor adhesion between the matrix and poly(MMA) beads. We also observed that the polymerization shrinkage increased as the amount of hydrophilic monomer in the formulation decreased, and the 50% (v/v) HPMA modified bone cement compensated for this volume reduction with its water uptake swelling. Measurements taken on the setting time and polymerization exotherm showed a decrease in the former and an increase in the latter, because of the introduction of a more reactive monomer in the bone cement formulation.

  3. Superparamagnetic polymer emulsion particles from a soap-free seeded emulsion polymerization and their application for lipase immobilization.

    PubMed

    Cui, Yanjun; Chen, Xia; Li, Yanfeng; Liu, Xiao; Lei, Lin; Zhang, Yakui; Qian, Jiayu

    2014-01-01

    Using emulsion copolymer of styrene (St), glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) as seed latexes, the superparamagnetic polymer emulsion particles were prepared by seeded emulsion copolymerization of butyl methacrylate (BMA), vinyl acetate (VAc) and ethylene glycol dimethacrylate in the presence of the seed latexes and superparamagnetic Fe3O4/SiOx nanoparticles (or Fe3O4-APTS nanoparticles) through a two-step process, without addition of any emulsifier. The magnetic emulsion particles named P(St-GMA-HEMA)/P(BMA-VAc) were characterized by transmission electron microscope and vibrating sample magnetometry. The results showed that the magnetic emulsion particles held a structure with a thinner shell (around 100 nm) and a bigger cavity (around 200 nm), and possessed a certain level of magnetic response. The resulting magnetic emulsion particles were employed in the immobilization of lipase by two strategies to immobilized lipase onto the resulting magnetic composites directly (S-1) or using glutaraldehyde as a coupling agent (S-2), thus, experimental data showed that the thermal stability and reusability of immobilized lipase based on S-2 were higher than that of S-1.

  4. The imaging study of a novel photopolymer used in I-line negative-tone resist

    NASA Astrophysics Data System (ADS)

    Liu, Lu; Zou, Yingquan

    2010-04-01

    By copolymerization of 2-(2-diazo-3-oxo-3-(4-dimethylaminophenyl)propionyloxy)ethyl methacrylate (DODMAPPEA), methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA), a photoactive polymer for negative-tone resist is synthesized and its photolithographic properties are investigated. Since the maximum-absorption wavelength of the photoactive monomer DODMAPPEA is 356nm and it still has a comparatively large absorption at 365nm (I-line), the copolymer poly(DODMAPPEA -co-MMA-co-HEMA) is anticipated to be used in I-line single component negative-tone resist. Upon irradiaton, the diazoketo groups which are in the side chains of the copolymers undergo the wolff rearrangement, affording ketenes that react with hydroxyl to provide cross-linking photoproducts and a negative image is obtained. Besides that, cross-linking agent hexamethoxymethylmelamine (HMMM) is added to the resist system and high sensitivity is expected. This kind of copolymer has great value in I-line non-CARs, TFT-LCD and IC discrete devices processing and the anti-dry etching ability is enhanced by the introduction of the benzene ring. In addition, this copolymer still has potential value in Ultra-violate lithographic plate.

  5. Opto-acoustic study of tinuvin-P and rhodamine 6G in solid polymeric matrices

    NASA Astrophysics Data System (ADS)

    Nonell, S.; Martí, C.; García-Moreno, I.; Costela, Á.; Sastre, R.

    Laser-induced opto-acoustic calorimetry has been used to examine the thermo-elastic properties of two polymer matrices doped with tinuvin-P and the radiation-less decay processes of rhodamine 6G (Rh6G) in them. The matrices assayed were methyl methacrylate (MMA) homopolymers P(MMA), and methyl methacrylate and 2-hydroxyethyl methacrylate (HEMA) copolymers P(MMA:HEMA). A slight difference in the thermo-elastic properties of the polymers, namely their adiabatic expansion coefficients, has been detected and found to correlate with the long-term stability of the laser material. This suggests a key role of the heat-dissipation processes in the photostability of these polymeric materials. On the other hand, the fluorescence quantum yield of Rh6G is shown to vary with the polymer-matrix composition in a way consistent with its lasing efficiency. The Rh6G absorption and fluorescence quantum yield also change dramatically upon increasing its concentration, which suggests the co-existence of different Rh6G forms with different photophysical properties.

  6. High-level soluble expression of the hemA gene from Rhodobacter capsulatus and comparative study of its enzymatic properties.

    PubMed

    Lou, Jia-wei; Zhu, Li; Wu, Mian-bin; Yang, Li-rong; Lin, Jian-ping; Cen, Pei-lin

    2014-05-01

    The Rhodobacter capsulatus hemA gene, which encodes 5-aminolevulinic acid synthase (ALAS), was expressed in Escherichia coli Rosetta (DE3) and the enzymatic properties of the purified recombinant ALAS (RC-ALAS) were studied. Compared with ALASs encoded by hemA genes from Agrobacterium radiobacter (AR-ALAS) and Rhodobacter sphaeroides (RS-ALAS), the specific activity of RC-ALAS reached 198.2 U/mg, which was about 31.2% and 69.5% higher than those of AR-ALAS (151.1 U/mg) and RS-ALAS (116.9 U/mg), respectively. The optimum pH values and temperatures of the three above mentioned enzymes were all pH 7.5 and 37 °C, respectively. Moreover, RC-ALAS was more sensitive to pH, while the other two were sensitive to temperature. The effects of metals, ethylene diamine tetraacetic acid (EDTA), and sodium dodecyl sulfate (SDS) on the three ALASs were also investigated. The results indicate that they had the same effects on the activities of the three ALASs. SDS and metal ions such as Co(2+), Zn(2+), and Cu(2+) strongly inhibited the activities of the ALASs, while Mn(2+) exerted slight inhibition, and K(+), Ca(2+), Ba(2+), Mg(2+), or EDTA had no significant effect. The specificity constant of succinyl coenzyme A [(kcat/Km)(S-CoA)] of RC-ALAS was 1.4989, which was higher than those of AR-ALAS (0.7456) and RS-ALAS (1.1699), showing its high catalytic efficiency. The fed-batch fermentation was conducted using the recombinant strain containing the R. capsulatus hemA gene, and the yield of 5-aminolevulinic acid (ALA) achieved was 8.8 g/L (67 mmol/L) under the appropriate conditions.

  7. Osteoblast cell death on methacrylate polymers involves apoptosis.

    PubMed

    Gough, J E; Downes, S

    2001-12-15

    The success of an implant depends on the implant-tissue interface. There are many causes of implant failure, one of which is tissue necrosis. The aim of this in vitro study was to determine whether cell death of primary human osteoblasts (implant site specific cells) occurred by apoptosis (a form of programmed cell death) on two methacrylate polymers. Cells were cultured on poly(ethyl methacrylate)/tetrahydrofurfuryl methacrylate and poly(methyl methacrylate in the form of 13-mm discs, in conditioned medium containing leachable monomer and in the presence of various concentrations of monomer itself in the culture medium. It was found that monomer and leached monomer caused apoptosis of human osteoblast cells in this system. Tetrahydrofurfuryl methacrylate monomer was found to be more toxic than currently used monomer methylmethacrylate. Preincubation of polymers in serum containing medium was found to increase the biocompatibility of the polymers. High levels of apoptosis occurred on polymer used directly after polymerization. Apoptosis levels were decreased after polymer was incubated at 60 degrees C overnight or for 3 days. Apoptosis therefore may occur in cells at the implant site in vivo.

  8. Preparation and in vitro evaluation of mucoadhesion and permeation enhancement of thiolated chitosan-pHEMA core-shell nanoparticles.

    PubMed

    Moghaddam, Firooze Aghaei; Atyabi, Fatemeh; Dinarvand, Rassoul

    2009-06-01

    The aim of the present work was to evaluate the in vitro mucoadhesion and permeation enhancement properties of thiolated chitosan (chitosan-glutathione) coated poly(hydroxyl ethyl methacrylate) nanoparticles. Core-shell nanoparticles were prepared by radical emulsion polymerization method initiated by cerium(IV) ammonium nitrate. Different molecular weights of chitosan were utilized for nanoparticles preparation. The physicochemical properties of nanoparticles were characterized by size, zeta potential, and thiol content. Incorporation of fluorescein isothiocyanate dextran (FD4, MW 4400 Da), which was used as the model macromolecule, was achieved by incubation method. The intestinal mucoadhesion and penetration enhancement properties of nanoparticles were investigated using excised rat jejunum. All nanoparticle systems showed mucoadhesion and improved apparent permeation coefficient (P(app)) of FD4. Nanoparticles prepared by thiolated chitosan with medium molecular weight revealed the most mucoadhesion and penetration enhancement properties.

  9. Complex microparticulate systems based on glycidyl methacrylate and xanthan.

    PubMed

    Lungan, Maria-Andreea; Popa, Marcel; Desbrieres, Jacques; Racovita, Stefania; Vasiliu, Silvia

    2014-04-15

    Porous microparticles based on glycidyl methacrylate, dimethacrylic monomers [ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate] and xanthan gum were synthesized by aqueous suspension polymerization method in the presence of toluene as diluent using two types of initiators: benzoyl peroxide and ammonium persulfate. The G microparticles based on glycidyl methacrylate and dimethacrylic monomers and X microparticles based on glycidyl methacrylate, xanthan and dimethacrylic monomers were characterized by various techniques including FT-IR spectroscopy, TG analysis, SEM analysis and DVS method. The specific surface areas were determined by DVS method, while the copolymer porosities and pore volume were obtained from the apparent and skeletal densities. The results have indicated that xanthan was included in the crosslinked matrix by means of covalent bonds. X microparticles have a porous structure with higher specific surface area (129-44 m(2)/g) and higher sorption capacities compared with G microparticles (69-31 m(2)/g).

  10. Health and Environmental Effects Profile for ethyl methacrylate

    SciTech Connect

    Not Available

    1986-06-01

    The Health and Environmental Effects Profile for ethyl methacrylate was prepared to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life and environmental effects. Quantitative estimates are presented provided sufficient data are available. Ethyl methacrylate has been determined to be a systemic toxicant. An acceptable daily intake (ADI) for ethyl methacrylate is 0.086 mg/kg/day for oral exposure.

  11. Protonation of diethylaminoethyl methacrylate by acids in various solvents

    SciTech Connect

    Zhuravleva, I.L.; Bune, E.V.; Bogachev, Yu.S.; Sheinker, A.P.; Teleshov, E.N.

    1988-04-10

    It was established by /sup 1/H and /sup 13/C NMR that diethylaminoethyl methacrylate exists in the unprotonated form in solvents which are not acids. In the presence of an equimolar amount of hydrochloric or trifluoroacetic acids the amino ester is fully protonated, irrespective of the solvent. The diethylaminoethyl methacrylate-acetic acid system exists in the form of a molecular complex with a hydrogen bond and in the protonated form; the proportions of the protonated form were estimated in various solvents. The change in the reactivity of diethylaminoethyl methacrylate and its salts in polymerization was explained by a change in the electronic state of CH/sub 2/ = group of the monomer as a result of its protonation and of the formation of a hydrogen bond between the C = O group of the monomer and the solvent.

  12. Poly(methyl methacrylate)-cellulose nitrate copolymers. I. Preparation

    SciTech Connect

    Badran, B.M.; Sherif, S.; Abu-Sedira, A.A.

    1981-03-01

    Poly(methyl methacrylate)-cellulose nitrate copolymers were prepared in the form of rods and sheets by bulk polymerization using benzoyl peroxide as initiator. Suspension polymerization did not succeed in preparing poly(methyl methacrylate)-cellulose nitrate copolymers, especially when cellulose nitrate of 11.4% nitrogen content was used. The parameters such as cellulose nitrate concentration, nitrogen content of cellulose nitrate, the amount of initiator and the reaction time, and the temperature are discussed. The prepared copolymers were irradiated for specified periods of up to 11.83 Mrad. It was found that poly(methyl methacrylate)-cellulose nitrate copolymers did not dissolve in any conventional solvent, but they swelled. Swelling decreases with increasing cellulose nitrate concentrations, nitrogen content of cellulose nitrate, and irradiation dose, indicating the crosslinked structure of the prepared copolymers.

  13. Detection and quantification of monomers in unstimulated whole saliva after treatment with resin-based composite fillings in vivo.

    PubMed

    Michelsen, Vibeke B; Kopperud, Hilde B M; Lygre, Gunvor B; Björkman, Lars; Jensen, Einar; Kleven, Inger S; Svahn, Johanna; Lygre, Henning

    2012-02-01

    Resin-based dental restorative materials contain allergenic methacrylate monomers, which may be released into saliva after restorative treatment. Monomers from resin-based composite materials have been demonstrated in saliva in vitro; however, studies analyzing saliva after restorative therapy are scarce. The aim of this study was to quantify methacrylate monomers in saliva after treatment with a resin-based composite filling material. Saliva was collected from 10 patients at four start points--before treatment, and 10 min, 24 h, and 7 d after treatment--and analysed by combined chromatography/mass spectrometry. The monomers bisphenol-A diglycidyl methacrylate (Bis-GMA), 2-hydroxyethyl methacrylate (HEMA), and urethane dimethacrylate (UDMA) were detected and quantified in the samples collected shortly (10 min) after treatment. The amounts detected ranged from 0.028 to 9.65 μg ml(-1) for Bis-GMA, from 0.015 to 0.19 μg ml(-1) for HEMA, and from 0.004 to 1.2 μg ml(-1) for UDMA. Triethyleneglycol dimethacrylate (TEGDMA) was detected in four of the samples. Ethoxylated bisphenol-A dimethacrylate (Bis-EMA) was not detected. Monomers were not detected in saliva samples collected before treatment, or 24 h or 7 d after treatment, with the exception of one sample, 24 h after treatment, in which HEMA was detected. In conclusion, monomers from the investigated resin-based composite and adhesive system were present in saliva shortly after treatment. One week after treatment, no monomers could be detected in patients' saliva samples.

  14. 40 CFR 721.10523 - Perfluoroalkylethyl methacrylate copolymer with hydroxymethyl acrylamide, vinyl chloride and long...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... copolymer with hydroxymethyl acrylamide, vinyl chloride and long chain fatty alkyl acrylate (generic). 721... Substances § 721.10523 Perfluoroalkylethyl methacrylate copolymer with hydroxymethyl acrylamide, vinyl... methacrylate copolymer with hydroxymethyl acrylamide, vinyl chloride and long chain fatty alkyl acrylate (PMN...

  15. 40 CFR 721.10523 - Perfluoroalkylethyl methacrylate copolymer with hydroxymethyl acrylamide, vinyl chloride and long...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... copolymer with hydroxymethyl acrylamide, vinyl chloride and long chain fatty alkyl acrylate (generic). 721... Substances § 721.10523 Perfluoroalkylethyl methacrylate copolymer with hydroxymethyl acrylamide, vinyl... methacrylate copolymer with hydroxymethyl acrylamide, vinyl chloride and long chain fatty alkyl acrylate (PMN...

  16. Review of Polymerization and Properties of Aminoalkyl Acrylates and Aminoalkyl Methacrylates

    DTIC Science & Technology

    1988-07-01

    to Russian investigators Korshunov, Bodnaryuk, and Kut’in, in 1975.2 The patent concerned the synthesis of methacrylate monomers containing an amino...group through transesterification. These researchers used alkyl methacrylates , mainly methyl methacrylate (MMA), as precursors for the synthesis. For...Ratios (rl, r2) of Aminoalkyl Methacrylates and Other Vinyl Monomers Monomer1 Moromer2 rl r2 DMAEMA MMA 0.717 0.676 DMAEMA BMA 0.705 0.66 BDIMA MMA 0.612

  17. Surface-Modified P(HEMA-co-MAA) Nanogel Carriers for Oral Vaccine Delivery: Design, Characterization, and In Vitro Targeting Evaluation

    PubMed Central

    Durán-Lobato, Matilde; Carrillo-Conde, Brenda; Khairandish, Yasmine; Peppas, Nicholas A.

    2015-01-01

    Oral drug delivery is a route of choice for vaccine administration because of its noninvasive nature and thus efforts have focused on efficient delivery of vaccine antigens to mucosal sites. An effective oral vaccine delivery system must protect the antigen from degradation upon mucosal delivery, penetrate mucosal barriers, and control the release of the antigen and costimulatory and immunomodulatory agents to specific immune cells (i.e., APCs). In this paper, mannan-modified pH-responsive P(HEMA-co-MAA) nanogels were synthesized and assessed as carriers for oral vaccination. The nanogels showed pH-sensitive properties, entrapping and protecting the loaded cargo at low pH values, and triggered protein release after switching to intestinal pH values. Surface decoration with mannan as carbohydrate moieties resulted in enhanced internalization by macrophages as well as increasing the expression of relevant costimulatory molecules. These findings indicate that mannan-modified P(HEMA-co-MAA) nanogels are a promising approach to a more efficacious oral vaccination regimen. PMID:24955658

  18. The lower alkyl methacrylates: Genotoxic profile of non-carcinogenic compounds.

    PubMed

    Albertini, Richard J

    2017-03-01

    All of the lower alkyl methacrylates are high production chemicals with potential for human exposure. The genotoxicity of seven mono-functional alkyl esters of methacrylic acid, i.e. methyl methacrylate, ethyl methacrylate, hydroxyethyl methacrylate, n-, i- and t-butyl methacrylate and 2 ethyl hexyl methacrylate, as well as methacrylic acid itself, the acyl component common to all, is reviewed and compared with the lack of carcinogenicity of methyl methacrylate, the representative member of the series so evaluated. Also reviewed are the similarity of structure, chemical and biological reactivity, metabolism and common metabolic products of this group of compounds which allows a category approach for assessing genotoxicity. As a class, the lower alkyl methacrylates are universally negative for gene mutations in prokaryotes but do exhibit high dose clastogenicity in mammalian cells in vitro. There is no convincing evidence that these compounds induce genotoxic effects in vivo in either sub-mammalian or mammalian species. This dichotomy of effects can be explained by the potential genotoxic intermediates generated in vitro. This genotoxic profile of the lower alkyl methacrylates is consistent with the lack of carcinogenicity of methyl methacrylate.

  19. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  20. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  1. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  2. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  3. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  4. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic.../methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers...

  5. Mössbauer studies of solid state decomposition of methyl methacrylate-ethyl methacrylate copolymers containing ferric chloride

    NASA Astrophysics Data System (ADS)

    Kapur, G. S.; Brar, A. S.

    1990-07-01

    Methyl methacrylate (MMA)-ethyl methacrylate (EMA) copolymers of different monomer concentrations containing anhydrous ferric chloride were prepared by bulk polymerization at 70°C. TGA studies showed that inclusion of iron salt increases the thermal stability of copolymers by 50°C. Mössbauer spectra of copolymers heated at different temperatures showed the presence of Fe3+ species only, in different environments. The mechanism of thermal stabilization of copolymer has been proposed on the basis of IR, TGA and Mössbauer spectroscopy studies.

  6. An evaluation of commercial and experimental resin-modified glass-ionomer cements

    NASA Astrophysics Data System (ADS)

    Kanchanavasita, Widchaya

    Glass-ionomer cement (GIG) has become widely accepted as a restorative material due to its bonding ability and sustained release of fluoride. The cement is, however, sensitive to moisture imbalance and lacks toughness. Recently, resin-modified glass-ionomer cements (RMGIC) have been introduced. These materials contain monomeric species, such as 2-hydroxyethyl methacrylate (HEMA) in addition to the components of the conventional glass-ionomer cements. Disadvantages of RMGICs include a relatively high contraction and exotherm on polymerisation. HEMA is known to be cytotoxic, leading to problems of biocompatibility, and polyHEMA swells on exposure to water, leading to dimensional instability of the cements. Addressing these problems is important in the development of the RMGICs. Using alternative monomers to replace or reduce the amount of HEMA used in the current RMGIC formulations would be appropriate. This study was divided into two parts. Initially certain properties such as water sorption, micro-hardness, flexural strength and polymerisation exotherm of commercially available RMGICs were evaluated. Long-term storage of RMGICs in aqueous solutions resulted in their high water uptakes and solubilities and large volumetric expansions. However, the surface hardness and strengths of the restorative grade RMGICs were not affected on storage in distilled water. When the materials were immersed in artificial saliva, significantly higher water uptake were obtained; the equilibrium water uptake were not reached after 20 months. As a consequence, plastic behaviour and reduced surface hardness were observed. The RMGICs also produced high exotherm during polymerisation. The second part of the study investigated the use of an experimental resin as an alternative to HEMA. The experimental resin has the advantage of low toxicity to the pulp and relatively low polymerisation shrinkage. This study compared the polymerisations of the resin and HEMA, and of mixtures of these two

  7. 21 CFR 177.1830 - Styrene-methyl methacrylate copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate copolymers identified in this section may be safely used as components of plastic articles... weight percent of polymer units derived from styrene. (b) The finished plastic food-contact article, when... not to exceed an absorbance of 0.15. (3) Ultraviolet-absorbing distilled water and 8 and 50...

  8. Synthesis of acrylates and methacrylates from coal-derived syngas

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Jang, B.W.L.

    1995-12-31

    Acrylates and methacrylates are among the most widely used chemical intermediates in the world. One of the key chemicals of this type is methyl methacrylate. Of the 4 billion pounds produced each year, roughly 85% is made using the acetone-cyanohydrin process, which requires handling of large quantities of hydrogen cyanide and produces ammonium sulfate wastes that pose an environmental disposal challenge. The U.S. Department of Energy and Eastman Chemical Company are sharing the cost of research to develop an alternative process for the synthesis of methyl methacrylate from syngas. Research Triangle Institute is focusing on the synthesis and testing of active catalysts for the condensation reactions, and Bechtel is analyzing the costs to determine the competitiveness of several process alternatives. Results thus far show that the catalysts for the condensation of formaldehyde and the propionate are key to selectively producing the desired product, methacrylic acid, with a high yield. These condensation catalysts have both acid and base functions and the strength and distribution of these acid-base sites controls the product selectivity and yield.

  9. Synthesis and Characterization of Carboxymethylcellulose-Methacrylate Hydrogel Cell Scaffolds

    PubMed Central

    Reeves, Robert; Ribeiro, Andreia; Lombardo, Leonard; Boyer, Richard; Leach, Jennie B.

    2012-01-01

    Many carbohydrates pose advantages for tissue engineering applications due to their hydrophilicity, degradability, and availability of chemical groups for modification. For example, carboxymethylcellulose (CMC) is a water-soluble cellulose derivative that is degradable by cellulase. Though this enzyme is not synthesized by mammalian cells, cellulase and the fragments derived from CMC degradation are biocompatible. With this in mind, we created biocompatible, selectively degradable CMC-based hydrogels that are stable in routine culture, but degrade when exposed to exogenous cellulase. Solutions of CMC-methacrylate and polyethylene glycol dimethacrylate (PEG-DM) were co-crosslinked to form stable hydrogels; we found that greater CMC-methacrylate content resulted in increased gel swelling, protein diffusion and rates of degradation by cellulase, as well as decreased gel shear modulus. CMC-methacrylate/PEG-DM gels modified with the adhesive peptide RGD supported fibroblast adhesion and viability. We conclude that hydrogels based on CMC-methacrylate are suitable for bioengineering applications where selective degradability may be favorable, such as cell scaffolds or controlled release devices. PMID:22708058

  10. Occupational asthma due to methyl methacrylate and cyanoacrylates.

    PubMed Central

    Lozewicz, S; Davison, A G; Hopkirk, A; Burge, P S; Boldy, D A; Riordan, J F; McGivern, D V; Platts, B W; Davies, D; Newman Taylor, A J

    1985-01-01

    Five patients had asthma provoked by cyanoacrylates and one by methyl methacrylate, possibly because of the development of a specific hypersensitivity response. Acrylates have wide domestic as well as industrial uses, and inhalation of vapour emitted during their use can cause asthma. PMID:4071461

  11. Reactive compatibilization of PBT/ABS blends by methyl methacrylate, glycidyl methacrylate, ethyl acrylate terpolymers

    NASA Astrophysics Data System (ADS)

    Hale, Wesley Raymond

    The impact resistance of poly(butylene terephthalate), PBT, has been improved by blending with acrylonitrile-butadiene-styrene terpolymers, ABS, as a minor dispersed phase; however, extensive coarsening of the dispersed phase in the blends occurs under certain heat fabrication conditions. The incorporation of certain reactive polymers (compatibilizers) that are miscible with the styrene/acrylonitrile (SAN) matrix of ABS should result in more stable morphologies. Terpolymers of methyl methacrylate, glycidyl methacrylate (GMA), ethyl acrylate, MGE, are effective as reactive compatibilizers for blends of PBT with SAN and ABS materials. The epoxide groups of MGE react with the carboxyl endgroups of PBT to form a MGE-g-PBT graft copolymer at the PBT/SAN interface to provide improved SAN or ABS dispersion, morphological stability, and a broadening of the melt processing window. Additionally, compatibilization produces large improvements in the low temperature fracture toughness of PBT/ABS blends; however, the toughness depends on the order of mixing blend components due to crosslinking reactions involving the epoxide groups of MGE catalyzed by residual acids present in some emulsion-made ABS materials. The PBT, ABS, and MGE type, content, and composition have been examined to evaluate their effects on the mechanical and morphological properties of PBT/ABS blends. Additionally, the effects of different processing conditions have been examined. High PBT melt viscosity is desirable for improving ABS dispersion and low temperature toughness of the blends. Generally, ABS materials with a high rubber content and low melt viscosity are desirable for toughening PBT. Moderate amounts of GMA in the blend were found to significantly improve blend properties. Melt blending can be performed using a variety of equipment; however, a co-rotating intermeshing twin screw extruder is the most effective for producing blends with excellent properties. The fracture properties of PBT

  12. Microfabrication of hydrogels for biomedical applications

    NASA Astrophysics Data System (ADS)

    Yu, Tianyue; Chiellini, Federica; Schmaljohan, Dirk; Solaro, Roberto; Ober, Christopher K.

    2002-07-01

    Hydrogels have gained general acceptance as biocompatible materials and are the basis of many promising applications in tissue engineering, drug release formulations and biosensors. Polymer processing techniques that can generate miniature hydrogel microstructures are not only critical as scaffolds for tissue re-growth but also very effective for increasing the efficiency of drug delivery and biosensors. Our approach is to use both optical and soft lithographic methods to microfabricate hydrogels. In this paper, we describe a photolithographic process to pattern hydrogel materials and analyze factors influencing sensitivity and lateral resolution. The model system we are investigating is based on 2-hydroxyethyl methacrylate (HEMA), which is well known for its non-toxicity and its widespread use in the contact lens industry.

  13. Photochemistry of tetraphenyldiboroxane and its use as photopolymerization coinitiator.

    PubMed

    Santos, Willy G; Schmitt, Carla C; Neumann, Miguel G

    2013-01-01

    2-Hydroxyethyl methacrylate (HEMA) was photopolymerized in the presence of Safranine (SfH(+)) and tetraphenyldiboroxane (TPhB). Polymerization results are correlated with the photochemistry of TPhB and its ability to aggregate forming hydrophobic domains (critical aggregation concentration, cac, 1.2 × 10(-4) M). Polymerization was not observed when the TPhB concentration was below the cac, indicating that the polymerization is initiated in the hydrophobic environment. The quenching of the triplet state of SfH(+) by TPhB and the generation of the semireduced species of SfH(+) suggests an electron transfer from the boron compound to the excited dye, and that the resulting boron-centered radical initiates the polymerization process.

  14. The prevention of microfouling and macrofouling on hydrogels impregnated with either Arquad 2C-75 or benzalkonium chloride.

    PubMed

    Cowie, Phillip R; Smith, Margaret J; Hannah, Fiona; Cowling, Mike J; Hodgkeiss, Trevor

    2006-01-01

    Optically clear, surfactant loaded poly (2-hydroxyethyl methacrylate) (pHEMA) hydrogels can be used to prevent fouling on optical windows of marine underwater sensors. To act successfully in this capacity, hydrogels need to prevent both microfouling and macrofouling. Panel trials were conducted using four different materials: unloaded hydrogels, hydrogels containing either benzalkonium chloride (BAC) or dicocodimethylammonium chloride (Arquad 2C-75) and PMMA coupons. Three panels were deployed at staggered intervals (2, 4 and 6 weeks) before the main settlement season of Semibalanus balanoides and Mytilus edulis in the Firth of Clyde, Scotland. Panels were left for a total period of 10, 12 and 14 weeks respectively. Results showed that no sample completely resisted fouling, but Arquad 2C-75 hydrogels were extremely effective at preventing both microfouling and macrofouling. The most heavily fouled materials were unloaded hydrogels and PMMA, despite differences in initial hydrophilicities. Arquad 2C-75 hydrogels were equally effective at preventing larval settlement, for up to 14 weeks.

  15. Optical and vibrational properties of phosphorylcholine-based contact lenses-Experimental and theoretical investigations.

    PubMed

    Filipecka, Katarzyna; Miedziński, Rafał; Sitarz, Maciej; Filipecki, Jacek; Makowska-Janusik, Małgorzata

    2017-04-05

    The Raman, MIR and UV-vis spectroscopy have been used to characterize Omafilcon A material constructing the one of the Proclear family contact lenses. The Omafilcon A is hydrogel material composed of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloyloxyethyl phosphorylcholine (PC) polymers crosslinked with ethyleneglycol dimethacrylate (EGDMA). Vibrational and electronic properties of the Omafilcon A material were also investigated by quantum chemical calculations. Experimentally obtained Raman, MIR and optical spectra were compared to the theoretical ones calculated applying RHF and DFT methodology. The quantum chemical calculations were performed for isolated monomers of lenses compounds as well as for their dimers and trimers to elucidate the effect of Omafilcon A polymerization and the role of an individual components.

  16. Modification of mechanical and thermal property of chitosan-starch blend films

    NASA Astrophysics Data System (ADS)

    Tuhin, Mohammad O.; Rahman, Nazia; Haque, M. E.; Khan, Ruhul A.; Dafader, N. C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

    2012-10-01

    Chitosan-starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan-starch films, glycerol and mustard oil of different composition were used. Chitosan-starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan-starch films. Water uptake of the films reduced significantly than the pure chitosan-starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively.

  17. Use of amino acid-based polymeric material for isolation of a protein from poison

    NASA Astrophysics Data System (ADS)

    Erol, Kadir; Köse, Kazım; Güngüneş, Hakan; Köse, Dursun Ali

    2017-02-01

    Melittin is a small protein with 126 amino acid residues which exists in the bee and snake venom. In this study, the Fe(II)-Ni(II) double-salt incorporated poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-aspartic acid), poly(HEMA-MAsp), magnetic microparticles were synthesized for the separation of melittin. Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and Mossbauer spectroscopy techniques were used for the characterization. The melittin adsorption capacity of magnetic microparticles in aqueous solution were identified as 69.60 mg/g, whereas that in real be venom solution was 46.80 mg/g microparticle. The adsorption-desorption cycle was repeated 5 times and no significant decrease were observed in the adsorption capacity.

  18. Ultraviolet-curable polymers with chemically bonded carbon nanotubes for microelectromechanical system applications

    NASA Astrophysics Data System (ADS)

    Xie, Jining; Zhang, Nanyan; Guers, Manton; Varadan, Vijay K.

    2002-08-01

    Current UV-curable polymer techniques for microelectromechanical system fabrication pose certain challenges due to the electrical and mechanical properties of the polymer. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in situ polymerization. Purified multi-walled nanotubes, obtained by the microwave chemical vapor deposition method, were functionalized by oxidation. X-ray photoelectron spectroscopy was used to identify the -OH and -COOH groups attached to the nanotube surface. The UV-curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between the -NCO groups of TDI and the -OH, -COOH groups of functionalized nanotubes were confirmed by Fourier transform infrared spectra. This new UV-curable polymer is expected to be a cost-effective solution with a variety of applications in UV coating, phase shifters for telecommunications and global positioning systems, and polymer and BioMEMS devices.

  19. Structural influence of the inorganic network in the laser performance of dye-doped hybrid materials

    NASA Astrophysics Data System (ADS)

    Costela, A.; García-Moreno, I.; García, O.; del Agua, D.; Sastre, R.

    2005-05-01

    We report a systematic study of the influence on the laser action of Rhodamine 6G (Rh6G) of the composition and structure of new hybrid matrices based on 2-hydroxyethyl methacrylate (HEMA) as organic monomer and different weight proportions of dimethyldiethoxysilane (DEOS) and tetraethoxysilane (TEOS) as inorganic part. We selected mixtures of di- and tetra-functionalized alkoxides trying to decrease, in a controlled way, the rigidity of the three-dimensional network by making use of the flexibility provided by the linear chains acting as a spacer of the inorganic domains. The organization of the molecular units in these nanomaterials was studied through a structural analysis by solid-state NMR. The different reactivity exhibited by di- and tetra-functionalized silanols generates a non-homogeneous tri-dimensional network. Thus, the laser performance in dye-doped hybrid materials is improved when the inorganic phase is composed of a unique alkoxide.

  20. UV-curable polymers with functionalized carbon nanotubes for MEMS

    NASA Astrophysics Data System (ADS)

    Xie, Jining; Zhang, Nanyan; Guers, Manton; Varadan, Vijay K.

    2003-07-01

    Current ultraviolet (UV) curable polymer techniques for MEMS fabrication pose certain challenges due to the electrical and mechanical properties of the polymer. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in-situ polymerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalized by oxidation. X-ray photoelectron spectroscopy (XPS) was used to identify the -OH and -COOH groups attached to nanotube surface. The UV curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between -NCO groups of TDI and -OH, -COOH groups of functionalized nanotubes were confirmed by Fourier transform infrared (FTIR) spectra. This new UV-curable polymer is expected to be a cost-effective solution with a variety of applications in UV coating, phase shifters for telecommunications and global positioning systems, and polymer and BioMEMS devices.

  1. Polyamide-6 nanocomposites with electron-beam-treated clay

    NASA Astrophysics Data System (ADS)

    Mészáros, László; Czvikovszky, Tibor

    2007-08-01

    The "in situ" polymerisation principle has been applied in our work to modify the efficiency of montmorillonite (MMT) as a reinforcement in polymer composites. The dry silica powder of MMT has been dispersed in (2-hydroxyethyl)-methacrylate (HEMA) monomer, and it has been treated by electron-beam (EB) and by heat. The treated silica powder has been mixed in polyamide (PA) melt by a Brabender kneader. The solid polymer samples have been tested for mechanical features as well as for dynamic-mechanical properties (DMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Surprisingly the thermally initiated "in situ" polymerisation was more efficient than 150 kGy EB dose in improving the composite properties.

  2. Observation of upconversion fluorescence and stimulated emission based on three-photon absorption

    NASA Astrophysics Data System (ADS)

    Yang, Q.; Lin, S.; Xu, L.; Yang, F.; Yang, Y.; Pan, L.; Sun, C.; Li, Y.; Sun, G.; Jiang, Z.

    2005-06-01

    The observations of three-photon-induced frequency-upconversion fluorescence and the highly directional stimulated visible emission in two dyes, 4-[p-(dicyanoethylamino) styryl]-N-methylpyridinium iodide (abbreviated as CEASP) and the complex of CEASP and Ce(NO3) (abbreviated as CEASP-Ce), are reported. The photographs of the forward amplified spontaneous emissions spots, pumped by an optical parametric oscillator idler with a pulse width of 8 ns and a wavelength of 1.3 μ m, are shown. The upconversion fluorescence produced both in dimethyl formamide solution and 2-hydroxyethyl methacrylate (HEMA) polymer spans from green to red, with a cubic dependence on the pump light intensity. The experimental results imply that the existence of the lanthanide ion Ce3 + sensitizes the nonlinear absorption and emission.

  3. Spectroscopic investigations into degradation of polymer membranes for fuel cells applications

    NASA Astrophysics Data System (ADS)

    Kruczała, Krzysztof; Szczubiałka, Krzysztof; Łańcucki, Łukasz; Zastawny, Izabela; Góra-Marek, Kinga; Dyrek, Krystyna; Sojka, Zbigniew

    2008-05-01

    The research was focused on synthesis of proton conductive, easily degradable polymer membranes, which can be used as a model system to verify the efficiency of transition metal ions (TMI) in prevention of polymer degradation. Two polymers composed of 2-hydroxyethyl methacrylate (HEMA), 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS), and styrenesulfonic acid (SS) were synthesized. The copolymers were characterized by gel permeation chromatography (GPC), elementary analysis, and FTIR and fluorescence spectroscopies. The results allowed determination of weight-average molecular weight and the copolymer composition. The protons of sulfonic groups were substituted by paramagnetic transition metal ions of various spin states (Cr 3+, S = 3/2 and Mn 2+, S = 5/2) with the loading varying from 0.5 up to 10 mol%. The effectiveness of spin catalysis was checked by EPR. The results obtained indicate enhancement of polymer stability in the presence of Mn 2+.

  4. Optical and vibrational properties of phosphorylcholine-based contact lenses-Experimental and theoretical investigations

    NASA Astrophysics Data System (ADS)

    Filipecka, Katarzyna; Miedziński, Rafał; Sitarz, Maciej; Filipecki, Jacek; Makowska-Janusik, Małgorzata

    2017-04-01

    The Raman, MIR and UV-vis spectroscopy have been used to characterize Omafilcon A material constructing the one of the Proclear family contact lenses. The Omafilcon A is hydrogel material composed of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloyloxyethyl phosphorylcholine (PC) polymers crosslinked with ethyleneglycol dimethacrylate (EGDMA). Vibrational and electronic properties of the Omafilcon A material were also investigated by quantum chemical calculations. Experimentally obtained Raman, MIR and optical spectra were compared to the theoretical ones calculated applying RHF and DFT methodology. The quantum chemical calculations were performed for isolated monomers of lenses compounds as well as for their dimers and trimers to elucidate the effect of Omafilcon A polymerization and the role of an individual components.

  5. Acrylate Systemic Contact Dermatitis.

    PubMed

    Sauder, Maxwell B; Pratt, Melanie D

    2015-01-01

    Acrylates, the 2012 American Contact Dermatitis Society allergen of the year, are found in a range of products including the absorbent materials within feminine hygiene pads. When fully polymerized, acrylates are nonimmunogenic; however, if not completely cured, the monomers can be potent allergens.A 28-year-old woman is presented, who had her teeth varnished with Isodan (Septodont, Saint-Maur-des-Fossés, France) containing HEMA (2-hydroxyethyl methacrylate) with no initial reaction. Approximately 1 month later, the patient developed a genital dermatitis secondary to her feminine hygiene pads. The initial reaction resolved, but 5 months later, the patient developed a systemic contact dermatitis after receiving a second varnishing.The patient was dramatically patch test positive to many acrylates. This case demonstrates a reaction to likely unpolymerized acrylates within a feminine hygiene pad, as well as broad cross-reactivity or cosensitivity to acrylates, and possibly a systemic contact dermatitis with systemic re-exposure to unpolymerized acrylates.

  6. Biodegradability and swelling capacity of kaolin based chitosan-g-PHEMA nanocomposite hydrogel.

    PubMed

    Pradhan, Arun Kumar; Rana, Pradeep Kumar; Sahoo, Prafulla Kumar

    2015-03-01

    Chitosan, a natural biopolymer, obtained by alkaline deacetylation of chitin, exhibits excellent biological properties such as biodegradability, immunological and antibacterial activity. Recently, there has been a growing interest in the chemical modification of chitosan in order to widen its applications. The chemical modification of chitosan has been achieved via grafting of monomer, 2-hydroxyethyl methacrylate (HEMA) in the presence of the initiator, ammonium persulfate (APS) and kaolin was added to improve the mechanical strength of the newly developed nanocomposites hydrogel. The so prepared grafted nanocomposites hydrogel was characterized by FTIR, XRD, SEM, TEM and TGA. The equilibrium water content (EWC) of the samples were measured at different pH ranges 6.5-8.0 and found optimum at pH 7.5 for biomedical applications. Further, the biodegradability of the samples was studied at different time intervals from 15 days to 1 year but, the kaolin based nanohydrogels exhibited good biodegradability.

  7. 3D Printed Silicone-Hydrogel Scaffold with Enhanced Physicochemical Properties.

    PubMed

    Mohanty, Soumyaranjan; Alm, Martin; Hemmingsen, Mette; Dolatshahi-Pirouz, Alireza; Trifol, Jon; Thomsen, Peter; Dufva, Martin; Wolff, Anders; Emnéus, Jenny

    2016-04-11

    Scaffolds with multiple functionalities have attracted widespread attention in the field of tissue engineering due to their ability to control cell behavior through various cues, including mechanical, chemical, and electrical. Fabrication of such scaffolds from clinically approved materials is currently a huge challenge. The goal of this work was to fabricate a tissue engineering scaffold from clinically approved materials with the capability of delivering biomolecules and direct cell fate. We have used a simple 3D printing approach, that combines polymer casting with supercritical fluid technology to produce 3D interpenetrating polymer network (IPN) scaffold of silicone-poly(2-hydroxyethyl methacrylate)-co-poly(ethylene glycol) methyl ether acrylate (pHEMA-co-PEGMEA). The pHEMA-co-PEGMEA IPN materials were employed to support growth of human mesenchymal stem cells (hMSC), resulting in high cell viability and metabolic activity over a 3 weeks period. In addition, the IPN scaffolds support 3D tissue formation inside the porous scaffold with well spread cell morphology on the surface of the scaffold. As a proof of concept, sustained doxycycline (DOX) release from pHEMA-co-PEGMEA IPN was demonstrated and the biological activity of released drug from IPN was confirmed using a DOX regulated green fluorescent reporter (GFP) gene expression assay with HeLa cells. Given its unique mechanical and drug releasing characteristics, IPN scaffolds may be used for directing stem cell differentiation by releasing various chemicals from its hydrogel network.

  8. Flat, Branched and Split Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Koombhongse, Sureeporn; Reneker, Darrell H.

    2001-03-01

    The electrospinning process uses electrical force to overcome the force from surface tension. As the electric field increases, the surface of a droplet becomes nearly conical and a charged jet flows from the vertex. The charged jet moves along a straight line for some distance and then begins a spiraling path, which is triggered by a bending instability.[1] The charged jet solidifies as it dries and electrospun nanofibers are collected. The electrospinning process normally produces cylindrical fibers, but sometimes the fibers are flat, branched or split. Flat fibers were electrospun from polystyrene (PS) and poly(2-hydroxyethyl methacrylate) (HEMA) solution. Flat fibers were formed by the collapse of a tube. Branched fibers of HEMA, PS and poly(vinylidene fluoride) were observed. The thinner branch was usually perpendicular to the axis of the primary jet. Branched fibers are formed by a smaller secondary jet ejected from the surface of the primary jet. The charged jet can split apart into two smaller jets to reduce the charge per unit surface area. Split fibers of HEMA, in which two smaller jets run parallel to the axis of the primary jet were observed. 1. D.H. Reneker, A.L. Yarin, H. Fong, and S. Koombhongse, J. Appl. Phys. 87, 4531 (2000).

  9. Release control of 9-β- D-arabinofuranosyladenine from thermo-responsive gels

    NASA Astrophysics Data System (ADS)

    Miyajima, Masaharu; Yoshida, Masaru; Sato, Hiroshi; Omichi, Hideki; Katakai, Ryoichi; Higuchi, William I.

    1995-08-01

    Hydrophilic 2-hydroxyethyl methacrylate (HEMA) and hydrophobic styrene (St) were introduced into a thermo-responsive gel of acryloyl- L-proline methyl ester (A-ProOMe) by means of radiation-induced copolymerization in the presence of a slight amount of crosslinker. The copolymer gels showed a reversible volume phase transition around 14°C and, as a result, it was found that the introduction of HEMA and St leads to the formation of a 'matrix pumping' gel which is characterized by a rapid shrinkage of the whole matrix without the disappearance of pores in the initial stageof deswelling. Such a thermo-responsive function appeared in limited composition ranges; 0-90 mol% HEMA and 0-50 mol% St. 9-β- D-Arabinofuranosyladenine (Ara-A) was incorporated into the A-ProOMe-containing gel to evaluate the release behavior of Ara-A when cycled between 10 and 37°C. The drug resulted in a pulsatile release consisting of a slight amount of drug release at 10°C and a good deal of drug release at 37°C, in closely relation to a matrix pumping mechanism.

  10. Soft contact lens biomaterials from bioinspired phospholipid polymers.

    PubMed

    Goda, Tatsuro; Ishihara, Kazuhiko

    2006-03-01

    Soft contact lens (SCL) biomaterials originated from the discovery of a poly(2-hydroxyethyl methacrylate) (poly[HEMA])-based hydrogel in 1960. Incorporation of hydrophilic polymers into poly(HEMA) hydrogels was performed in the 1970-1980s, which brought an increase in the equilibrium water content, leading to an enhancement of the oxygen permeability. Nowadays, the poly(HEMA)-based hydrogels have been applied in disposable SCL. At the same time, high oxygen-permeable silicone hydrogels were produced, which made it possible to continually wear SCL. Recently, numerous trials for improving the water wettability of silicone hydrogels have been performed. However, little attention has been paid to improving their anti-biofouling properties and biocompatibility. Since biomimetic phospholipid polymers possess excellent anti-biofouling properties and biocompatibility they have the potential to play a valuable role in the surface modification of the silicone hydrogel. The representative phospholipid polymers containing a 2-methacryloyloxyethyl phosphorylcholine (MPC) unit suppressed nonspecific protein adsorption, increased cell compatibility and contributed to blood compatible biomaterials. The MPC polymer coating on the silicone hydrogel improved its water wettability and biocompatibility, while maintaining high oxygen permeability compared with the original silicone hydrogel. Furthermore, the newly prepared phospholipid-type intermolecular crosslinker made it possible to synthesize a 100% phospholipid polymer hydrogel that can enhance the anti-biofouling properties and biocompatibility. In this review, the authors discuss how polymer hydrogels should be designed in order to obtain a biocompatible SCL and future perspectives.

  11. Development of MDP-based one-step self-etch adhesive--effect of additional 4-META on bonding performance.

    PubMed

    Iwai, Hitoshi; Fujita, Kou; Iwai, Hirotoshi; Ikemi, Takuji; Goto, Haruhiko; Aida, Masahiro; Nishiyama, Norihiro

    2013-01-01

    We designed three experimental 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based one-step (EX) adhesives consisting of MDP, urethane dimethacrylate, and triethylene glycol dimethacrylate adhesives with different water contents (98.4, 196.8, and 294.4 mg/g), and 4-methacryloyloxyethyl trimellitic anhydride (4-META) or 2-hydroxyethyl methacrylate (HEMA)-containing onestep adhesive. The effect of the amount of MDP-calcium (MDP-Ca) salt produced through demineralization of enamel and dentin on the bonding performance was examined. The efficacy of 4-META and HEMA was then discussed. When the amount of water in EX adhesive was increased, the production amount of MDP-Ca salt of enamel increased, but not the dentin. The enamel bond strength slightly increased with increasing the production amount of MDP-Ca salt, in contrast to the dentin. However, addition of 4-META in the EX adhesive (water content=98.4 mg/g) increased both bond strengths, although the production amounts of MDP-Ca salt significantly decreased. The 4-META enhances both bond strengths more effectively than the HEMA.

  12. Preparation and characterization of a hydrogel carrier to deliver gatifloxacin and its application as a therapeutic contact lens for bacterial keratitis therapy.

    PubMed

    Shi, Yunfeng; Lv, Hongling; Fu, Yeyun; Lu, Qingjun; Zhong, Jingxiang; Ma, Dong; Huang, Yuexin; Xue, Wei

    2013-10-01

    A soft and biocompatible hydrogel exhibiting a higher loading and the sustained release of gatifloxacin (GFLX) was developed as the potential matrix to fabricate a therapeutic contact lens for curing bacterial keratitis. 2-hydroxyethyl methacrylate (HEMA) and five other kinds of vinyl monomers with different side groups were used as co-monomers. Copolymerization took place in a cornea shaped mould via the gradient temperature-elevating method. The results of drug loading and in vitro release experiments showed that P(HEMA-co-MAA) achieved the highest drug loading of 11.78±0.77 µg mg(-1) among the obtained hydrogels, as well as a slow release. In addition, its physical properties and cytocompatibility were also proved suitable and safe for wearing on the eye surface. In animal experiments, a rat model of bacterial keratitis was established and employed to evaluate the clinical results of certain treatments employing obtained hydrogels; saline and GFLX eye drops were used as negative and positive controls, respectively. Corneal abscess and opacity caused by epithelial erosion and stromal ulceration were almost healed after wearing the drug loaded P(HEMA-co-MAA) hydrogel for 48 h. Its excellent antibacterial effect was also confirmed by testing the bacterial activity in tear extraction via the streak line method.

  13. “Methods to promote Notch signaling at the biomaterial interface and evaluation in a rafted organ culture model”

    PubMed Central

    Beckstead, Benjamin L.; Tung, Jason C.; Liang, Katharine J.; Tavakkol, Zarry; Usui, Marcia L.; Olerud, John E.; Giachelli, Cecilia M.

    2013-01-01

    The Notch signaling pathway is a promising target for controlling cell fate choices at the biomaterial-tissue interface. Building on our previous work in developing Notch-signaling biomaterials, we evaluated various immobilization schemes for Notch ligands and their effect on human foreskin keratinocytes. A peptide sequence derived from the Jagged-1 DSL-region and immobilized to poly (2-hydroxyethyl methacrylate) (polyHEMA) showed no bioactivity in relation to the Notch-CSL pathway. The full-length Jagged-1 protein immobilized directly to the polyHEMA surface showed activity in signaling the Notch-CSL pathway. However, an indirect affinity immobilization approach yielded a stronger signal. Human keratinocytes plated on bound Jagged-1 showed upregulated involucrin, keratin 10, and loricrin protein expression, with this expression being cell density-dependent. Utilizing a human foreskin rafted organ culture model as a bridge between in vitro and in vivo studies, Jagged-1-modified or control polyHEMA rods were implanted in human foreskin and cultured at the air-medium interface. Keratinocyte proliferation was suppressed and intermediate-stage differentiation promoted in Jagged-1-modified rods compared to control rods. Thus, Notch-signaling biomaterials provide a robust approach to control keratinocyte differentiation and may find application to other progenitor and stem cells. PMID:18985776

  14. Preparation of polymer gel dosimeters based on less toxic monomers and gellan gum

    NASA Astrophysics Data System (ADS)

    Hiroki, A.; Sato, Y.; Nagasawa, N.; Ohta, A.; Seito, H.; Yamabayashi, H.; Yamamoto, T.; Taguchi, M.; Tamada, M.; Kojima, T.

    2013-10-01

    New polymer gel dosimeters consisting of 2-hydroxyethyl methacrylate (HEMA), triethylene glycol monoethyl ether monomethacrylate (TGMEMA), polyethylene glycol 400 dimethacrylate (9G), tetrakis (hydroxymethyl) phosphonium chloride as an antioxidant, and gellan gum as a gel matrix were prepared. They were optically analyzed by measuring absorbance to evaluate a dose response. The absorbance of the polymer gel dosimeters that were exposed to 60Co γ-rays increased with increasing dose. The dosimeters comprising HEMA and 9G showed a linear increase in absorbance in the dose range from 0 to 10 Gy. The dose response depended on the 9G concentration. For others comprising HEMA, 9G and TGMEMA, the absorbance of the polymer gel dosimeters drastically increased above a certain dose, and then leveled off up to 10 Gy. The optical variations in these polymer gel dosimeters were also induced by x-irradiation from Cyberknife radiotherapy equipment. Furthermore, the exposed region of the latter polymer gel dosimeter exhibited a thermo-responsive behavior.

  15. Spectroscopic studies (FTIR, FT-Raman and UV), potential energy surface scan, normal coordinate analysis and NBO analysis of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl) piperidine-3,4,5-triol by DFT methods.

    PubMed

    Isac Paulraj, E; Muthu, S

    2013-05-01

    This work presents the characterization of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (abbreviated as HEHMPT) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman and UV-Vis techniques. The FT-IR spectrum (4000-400 cm(-1)) and FT-Raman spectrum (4000-100 cm(-1)) in solid phase was recorded for HEHMPT. The UV-Vis absorption spectrum of the HEHMPT that dissolved in water was recorded in the range of 100-400 nm. The structural and spectroscopic data of the molecule were obtained from B3LYP and M06-2X with 6-31G(d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the normal co-ordinate analysis (NCA), experimental results and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stable geometry of the compound has been determined from the potential energy surface scan. The stability of molecule has been analyzed by NBO analysis. The molecule orbital contributions were studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The electronic properties like UV spectral analysis and HOMO-LUMO energies were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges is also calculated.

  16. Poly(methacrylic acid-co-methyl methacrylate) beads promote vascularization and wound repair in diabetic mice.

    PubMed

    Martin, Daniel C; Semple, John L; Sefton, Michael V

    2010-05-01

    Topical application of beads made from poly(methacrylic acid-co-methyl methacrylate) (45 mol % methacrylic acid, MAA) increased the number of blood vessels and improved 1.5 x 1.5 cm full thickness wound closure in a diabetic mouse (db/db) model. Three groups were compared: MAA beads, control poly(methyl methacrylate) beads (PMMA), and no bead blanks. MAA bead treatment significantly increased percent wound closure at all timepoints (7, 14, and 21 days) with MAA bead-treated wounds almost closed at day 21 (91 +/- 5.4% MAA vs. 79 +/- 3.2% PMMA or 76 +/- 4.8% no beads; p < 0.05). This was consistent with the expected significant increase in vascularity in the MAA group at days 7 and 14. For example at day 14, MAA bead-treated wounds had a vascular density of 22.7 +/- 2.6 vessels/hpf compared with 17.0 +/- 2.0 vessels/hpf in the PMMA bead group (p < 0.05). Epithelial gap and migration measurements suggested that the increased vascularity leads to enhanced epithelial cell migration as a principal means of wound closure. Although studies are underway to elucidate the mechanism of this angiogenic response, the results presented here support the notion that such materials, perhaps in other forms, may be useful in wound care or in other situations where vascularity is to be enhanced without the use of exogenous growth factors.

  17. Poly(sulfobetaine methacrylate)s as electrode modifiers for inverted organic electronics.

    PubMed

    Lee, Hyunbok; Puodziukynaite, Egle; Zhang, Yue; Stephenson, John C; Richter, Lee J; Fischer, Daniel A; DeLongchamp, Dean M; Emrick, Todd; Briseno, Alejandro L

    2015-01-14

    We demonstrate the use of poly(sulfobetaine methacrylate) (PSBMA), and its pyrene-containing copolymer, as solution-processable work function reducers for inverted organic electronic devices. A notable feature of PSBMA is its orthogonal solubility relative to solvents typically employed in the processing of organic semiconductors. A strong permanent dipole moment on the sulfobetaine moiety was calculated by density functional theory. PSBMA interlayers reduced the work function of metals, graphene, and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by over 1 eV, and an ultrathin interlayer of PSBMA reduced the electron injection barrier between indium tin oxide (ITO) and C70 by 0.67 eV. As a result, the performance of organic photovoltaic devices with PSBMA interlayers is significantly improved, and enhanced electron injection is demonstrated in electron-only devices with ITO, PEDOT:PSS, and graphene electrodes. This work makes available a new class of dipole-rich, counterion-free, pH insensitive polymer interlayers with demonstrated effectiveness in inverted devices.

  18. Polymer composites reinforced by locking-in a liquid-crystalline assembly of cellulose nanocrystallites.

    PubMed

    Tatsumi, Mio; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2012-05-14

    An attempt was made to synthesize novel composites comprising poly(2-hydroxyethyl methacrylate) (PHEMA) and cellulose nanocrystallites (CNC) (acid-treated cotton microfibrils) from suspensions of CNC in an aqueous 2-hydroxyethyl methacrylate (HEMA) monomer solution. The starting suspensions (∼5 wt % CNC) separated into an isotropic upper phase and an anisotropic bottom one in the course of quiescent standing. By way of polymerization of HEMA in different phase situations of the suspensions, we obtained films of three polymer composites, PHEMA-CNC(iso), PHEMA-CNC(aniso), and PHEMA-CNC(mix), coming from the isotropic phase, anisotropic phase, and embryonic nonseparating mixture, respectively. All the composites were transparent and, more or less, birefringent under a polarized optical microscope. A fingerprint texture typical of cholesteric liquid crystals of longer pitch spread widely in PHEMA-CNC(aniso) but rather locally appeared in PHEMA-CNC(iso). Any of the CNC incorporations into the PHEMA matrix improved the original thermal and mechanical properties of this amorphous polymer material. In dynamic mechanical measurements, the locking-in of the respective CNC assemblies gave rise to an increase in the glass-state modulus E' of PHEMA as well as a marked suppression of the E'-falling at temperatures higher than T(g) (≈ 110 °C) of the vinyl polymer. It was also observed for the composites that their modulus E' rerose in a range of about 150-190 °C, which was attributable to a secondary cross-linking formation between PHEMA chains mediated by the acidic CNC filler. The mechanical reinforcement effect of the CNC dispersions was ensured in a tensile test, whereby PHEMA-CNC(aniso) was found to surpass the other two composites in stiffness and strength.

  19. Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups.

    PubMed

    Seo, Ji-Hun; Nakagawa, Shino; Hirata, Koichiro; Yui, Nobuhiko

    2014-01-01

    A resin monomer-soluble polyrotaxane (PRX) crosslinker with cleavable end groups was synthesized to develop degradable photosetting composite resins. The PRX containing 50 α-cyclodextrins (α-CDs) with disulfide end groups was initially modified with n-butylamine to obtain a resin monomer-soluble PRX. The PRX containing 13 n-butyl groups per α-CD molecule was completely soluble in conventional resin monomers such as 2-hydroxyethyl methacrylate (HEMA) and urethane dimethacrylate (UDMA). The synthesized n-butyl-containing PRX was further modified with 2-aminoethyl methacrylate to provide crosslinkable acrylic groups onto PRX. The prepared resin monomer-soluble PRX crosslinker was successfully polymerized with a mixture of HEMA and UDMA to provide photosetting plastic. It was confirmed that the Vickers hardness of the prepared plastic was greatly decreased after treatment with dithiothreitol. This indicates that the resin monomer-soluble PRX crosslinker can be applied to design degradable photosetting plastics potentially used in the industrial or biomedical field.

  20. Synthesis, structure, and physical properties of hybrid nanocomposites for solid-state dye lasers.

    PubMed

    García-Moreno, I; Costela, A; Cuesta, A; García, O; del Agua, D; Sastre, R

    2005-11-24

    We report on the synthesis, structural characterization, physical properties, and lasing action of two organic dyes, Rhodamine 6G (Rh6G) and Pyrromethene 597 (PM597), incorporated into new hybrid organic-inorganic materials, where the organic component was either poly(2-hydroxyethyl-methacrylate) (PHEMA) or copolymers of HEMA with methyl methacrylate (MMA), and the inorganic counterpart consisted of silica derived from hydrolysis-condensation of methyltriethoxysilane (TRIEOS) in weight proportion of up to 30%. Lasing efficiencies of up 23% and high photostabilities, with no sign of degradation in the initial laser output after 100 000 pump pulses at 10 Hz, were demonstrated when pumping the samples transversely at 534 nm with 5.5 mJ/pulse. A direct relationship could be established between the structure of the hybrid materials, analyzed by solid-state NMR, and their laser behavior. An inorganic network dominated by di-/tri- substituted silicates in a proportion approximately 35:65, corresponding to samples of HEMA with 15 and 20 wt % proportion of TRIEOS, optimizes the lasing photostability. The thermal properties of these materials, together with the high homogeneity revealed by atomic force microscopy (AFM) images, even in compounds with high silica content, indicate their microstructure to be a continuous phase, corresponding to the polymer matrix, which "traps" the silica components at molecular level via covalent bonding, with few or no silica islands.

  1. Laser Performance of Some Oxazole Laser Dyes in Restricted Matrices.

    PubMed

    Sakr, Mahmoud A S; Abdel Gawad, Sayed A; Abou Kana, Maram T H; Ebeid, El-Zeiny M

    2017-03-13

    This article reports the optical properties such as absorption profile, molar absorptivity, fluorescence profile and photo-physical parameters such as dipole moment, oscillator strength, fluorescence quantum yields, fluorescence lifetimes, laser performance and finally photostability of 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT),1,4-Bis(5-phenyl-2-oxazolyl)benzene (POPOB), 5-diphenyel-oxazole (PPO) laser dyes in different restricted hosts. (BBOT), (POPOB) and (PPO) are embedded in transparent silica-based nanoporous sol-gel glass and copolymer matrix of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA). The absorption and fluorescence properties of these laser dyes in sol-gel glass matrices are compared with their respective properties in copolymer host. In case of sol-gel matrix, all dyes had higher quantum yields as well as lasing wavelength maxima. The laser performances as well as the photostability of these laser dyes in sol-gel glass displayed senior behavior compared with (MMA/ HEMA) copolymer samples upon using nitrogen laser (337.1 nm) as pumping energy.

  2. Solid coatings deposited from liquid methyl methacrylate via Plasma Polymerization

    NASA Astrophysics Data System (ADS)

    Wurlitzer, Lisa; Maus-Friedrichs, Wolfgang; Dahle, Sebastian

    2016-09-01

    The polymerization of methyl methacrylate via plasma discharges is well known today. Usually, plasma-enhanced chemical vapor deposition (PECVD) is used to deposit polymer coatings. Solid coatings are formed out of the liquid phase from methyl methacrylate via dielectric barrier discharge. The formation of the coating proceeds in the gas and the liquid phase. To learn more about the reactions in the two phases, the coatings from MMA monomer will be compared to those from MMA resin. Finally, attenuated total reflection infrared spectroscopy, confocal laser scanning microscopy and X-ray photoelectron spectroscopy are employed to characterize the solid coatings. In conclusion, the plasma enhanced chemical solution deposition is compared to the classical thermal polymerization of MMA.

  3. Azulene methacrylate polymers: synthesis, electronic properties, and solar cell fabrication.

    PubMed

    Puodziukynaite, Egle; Wang, Hsin-Wei; Lawrence, Jimmy; Wise, Adam J; Russell, Thomas P; Barnes, Michael D; Emrick, Todd

    2014-08-06

    We report the synthesis of novel azulene-substituted methacrylate polymers by free radical polymerization, in which the azulene moieties represent hydrophobic dipoles strung pendant to the polymer backbone and impart unique electronic properties to the polymers. Tunable optoelectronic properties were realized by adjusting the azulene density, ranging from homopolymers (having one azulene group per repeat unit) to copolymers in which the azulene density was diluted with other pendant groups. Treating these polymers with organic acids revealed optical and excitonic behavior that depended critically on the azulene density along the polymer chain. Copolymers of azulene with zwitterionic methacrylates proved useful as cathode modification layers in bulk-heterojunction solar cells, where the relative azulene content affected the device metrics and the power conversion efficiency reached 7.9%.

  4. Physical properties of agave cellulose graft polymethyl methacrylate

    SciTech Connect

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-27

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  5. [Chest granuloma secondary to methyl methacrylate. Case report].

    PubMed

    Martínez-Bistrain, Ricardo; Robles García, Verónica; Cornejo-Morales, Ivonne

    2010-01-01

    We present the case of a patient with a history of a massive left hemithorax crushing injury in 1985; the exact management of the lesion is unknown. Twenty years later he had a thoracic fistula with a culture that was reported as positive for Enteroccocus faecalis and Staphyloccocus epidermidis. The patient was referred by the chest surgery service with the diagnosis of rib osteomyelitis once complementary imaging tests were performed (plain X-rays, CAT scan and MRI). The patient underwent surgery at our service; a granulomatous reaction secondary to a foreign body (methyl methacrylate and Ethibon) was reported. Chest reconstruction for massive lesions is possible with methyl methacrylate. Imaging studies involve the well-known difficulty to identify this material, given that it may produce signals and densities that are difficult to interpret by specialized physicians.

  6. Penile enlargement with methacrylate injection: is it safe?

    PubMed

    Torricelli, Fabio Cesar Miranda; Andrade, Enrico Martins de; Marchini, Giovanni Scala; Lopes, Roberto Iglesias; Claro, Joaquim Francisco Almeida; Cury, Jose; Srougi, Miguel

    2013-01-01

    CONTEXT Penis size is a great concern for men in many cultures. Despite the great variety of methods for penile augmentation, none has gained unanimous acceptance among experts in the field. However, in this era of minimally invasive procedure, injection therapy for penile augmentation has become more popular. Here we report a case of methacrylate injection in the penis that evolved with penile deformity and sexual dysfunction. This work also reviews the investigation and management of this pathological condition. CASE REPORT A 36-year-old male sought medical care with a complaint of penile deformity and sexual dysfunction after methacrylate injection. The treatment administered was surgical removal. Satisfactory cosmetic and functional results were reached after two months. CONCLUSIONS There is a need for better structured scientific research to evaluate the outcomes and complication rates from all penile augmentation procedures.

  7. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi; Samuel S. Tam

    1999-04-21

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (January-March/99), in-situ formaldehyde generation and condensation with methyl propionate were tested over various catalysts and reaction conditions. The patent application is in preparation and the results are retained for future reports.

  8. Positron annihilation investigations on poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Mohamed, Hamdy F. M.; Abd-Elsadek, Gomaa G.

    2000-06-01

    Positron lifetime and Doppler broadened annihilation radiation were measured for seven different samples of poly(methyl methacrylate) at room temperature in vacuum. The polymerisation of methyl methacrylate was carried out as a bulk polymerisation in the presence of benzoyl peroxide as an initiator. The effect of the amount of the initiator on the viscosity-average molecular weight was studied. It was found that the viscosity-average molecular weight decreased with increasing amount of the initiator. The average lifetime and intensity of ortho-positronium ( o-Ps) increased with increasing viscosity-average molecular weight up to 6.85 × 10 4 and remained constant after that. The S-parameter showed a similar behaviour as that of the o-Ps intensity.

  9. Preparation and characterization of methacrylate hydrogels for zeta potential control

    NASA Technical Reports Server (NTRS)

    Gregonis, D. E.; Ma, S. M.; Vanwagenen, R.; Andrade, J. D.

    1976-01-01

    A technique based on the measurement of streaming potentials has been developed to evaluate the effects of hydrophilic coatings on electroosmotic flow. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of glass capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming potential measurements is discussed. Various silane adhesion promoters exhibited only a slight decrease in streaming potential. A coating utilizing a glycidoxy silane base upon which methylcellulose is applied affords a six-fold decrease over uncoated tubes. Hydrophilic methacrylate gels show similar streaming potential behavior, independent of the water content of the gel. By introduction of positive or negative groups into the hydrophilic methacrylate gels, a range of streaming potential values are obtained having absolute positive or negative signs.

  10. Physical properties of agave cellulose graft polymethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-01

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm-1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  11. SYNTHESIS OF METHACRYLATES FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Jang, B.W.L.; Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.

    1999-12-01

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel have developed a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the US Department of Energy/Fossil Energy Technology Center (DOE/FETC). This project has resulted in five US patents (four already published and one pending publication). It has served as the basis for the technical and economic assessment of the production of this high-volume intermediate from coal-derived synthesis gas. The three-step process consists of the synthesis of a propionate from ethylene carbonylation using coal-derived CO, condensation of the propionate with formaldehyde to form methacrylic acid (MAA); and esterification of MAA with methanol to yield MMA. The first two steps, propionate synthesis and condensation catalysis, are the key technical challenges and the focus of the research presented here.

  12. Pediatric poisonings from household products: hydrofluoric acid and methacrylic acid.

    PubMed

    Perry, H E

    2001-04-01

    Household products continue to be a cause of poisoning morbibidity and mortality. Young children frequently are exposed to cleaning products and cosmetics in the course of exploring their environment. Most of these exposures are insignificant, but some result in death or permanent disability. This review discusses two products that have been responsible for serious injury and death in children: hydrofluoric acid and methacrylic acid. It also discusses federal initiatives designed to protect children from these and other household hazards.

  13. Gelatin methacrylate microspheres for controlled growth factor release.

    PubMed

    Nguyen, Anh H; McKinney, Jay; Miller, Tobias; Bongiorno, Tom; McDevitt, Todd C

    2015-02-01

    Gelatin has been commonly used as a delivery vehicle for various biomolecules for tissue engineering and regenerative medicine applications due to its simple fabrication methods, inherent electrostatic binding properties, and proteolytic degradability. Compared to traditional chemical cross-linking methods, such as the use of glutaraldehyde (GA), methacrylate modification of gelatin offers an alternative method to better control the extent of hydrogel cross-linking. Here we examined the physical properties and growth factor delivery of gelatin methacrylate (GMA) microparticles (MPs) formulated with a wide range of different cross-linking densities (15-90%). Less methacrylated MPs had decreased elastic moduli and larger mesh sizes compared to GA MPs, with increasing methacrylation correlating to greater moduli and smaller mesh sizes. As expected, an inverse correlation between microparticle cross-linking density and degradation was observed, with the lowest cross-linked GMA MPs degrading at the fastest rate, comparable to GA MPs. Interestingly, GMA MPs at lower cross-linking densities could be loaded with up to a 10-fold higher relative amount of growth factor than conventional GA cross-linked MPs, despite the GA MPs having an order of magnitude greater gelatin content. Moreover, a reduced GMA cross-linking density resulted in more complete release of bone morphogenic protein 4 and basic fibroblast growth factor and accelerated release rate with collagenase treatment. These studies demonstrate that GMA MPs provide a more flexible platform for growth factor delivery by enhancing the relative binding capacity and permitting proteolytic degradation tunability, thereby offering a more potent controlled release system for growth factor delivery.

  14. Gelatin Methacrylate Microspheres for Growth Factor Controlled Release

    PubMed Central

    Nguyen, Anh H.; McKinney, Jay; Miller, Tobias; Bongiorno, Tom; McDevitt, Todd C.

    2014-01-01

    Gelatin has been commonly used as a delivery vehicle for various biomolecules for tissue engineering and regenerative medicine applications due to its simple fabrication methods, inherent electrostatic binding properties, and proteolytic degradability. Compared to traditional chemical cross-linking methods, such as the use of glutaraldehyde (GA), methacrylate modification of gelatin offers an alternative method to better control the extent of hydrogel cross-linking. Here we examined the physical properties and growth factor delivery of gelatin methacrylate (GMA) microparticles formulated with a wide range of different cross-linking densities (15–90%). Less methacrylated MPs had decreased elastic moduli and larger mesh sizes compared to GA MPs, with increasing methacrylation correlating to greater moduli and smaller mesh sizes. As expected, an inverse correlation between microparticle cross-linking density and degradation was observed, with the lowest cross-linked GMA MPs degrading at the fastest rate, comparable to GA MPs. Interestingly, GMA MPs at lower cross-linking densities could be loaded with up to a 10-fold higher relative amount of growth factor over conventional GA cross-linked MPs, despite an order of magnitude greater gelatin content of GA MPs. Moreover, a reduced GMA cross-linking density resulted in more complete release of bone morphogenic protein 4 (BMP4) and basic fibroblast growth factor (bFGF) and accelerated release rate with collagenase treatment. These studies demonstrate that GMA MPs provide a more flexible platform for growth factor delivery by enhancing the relative binding capacity and permitting proteolytic degradation tunability, thereby offering a more potent controlled release system for growth factor delivery. PMID:25463489

  15. Enhanced surface segregation of poly(methyl methacrylate) end-capped with 2-perfluorooctylethyl methacrylate by introduction of a second block.

    PubMed

    Ni, Huagang; Gao, Jie; Li, Xuehua; Hu, Yanyan; Yan, Donghuan; Ye, XiuYun; Wang, Xinping

    2012-01-01

    New fluorinated copolymers of poly(methyl methacrylate)-b-poly(butyl methacrylate) or poly(n-octadecyl methacrylate) end-capped with 2-perfluorooctylethyl methacrylate (PMMA(x)-b-PBMA(y)-ec-PFMA(z) or PMMA(x)-b-PODMA(y)-ec-PFMA(z)) were synthesized by living atom transfer radical polymerization. Thin films made of PMMA(230)-b-PODMA(y)-ec-PFMA(1) were characterized by differential scanning calorimetry, angle-resolved X-ray photoelectron spectroscopy and X-ray diffraction. These films were found to exhibit robust surface segregation of the end groups. Furthermore, the fluorine enrichment factor at the film surface was found to increase linearly with increasing degree of polymerization of poly(n-octadecyl methacrylate) and its increasing fusion enthalpy in the second block, which enhances the segregation of the fluorinated moieties.

  16. Multifunctional methacrylate-based coatings for glass and metal surfaces

    NASA Astrophysics Data System (ADS)

    Pospiech, Doris; Jehnichen, Dieter; Starke, Sandra; Müller, Felix; Bünker, Tobias; Wollenberg, Anne; Häußler, Liane; Simon, Frank; Grundke, Karina; Oertel, Ulrich; Opitz, Michael; Kruspe, Rainer

    2017-03-01

    In order to prevent freshwater biofouling glass and metal surfaces were coated with novel transparent methacrylate-based copolymers. The multifunctionality of the copolymers, such as adhesion to the substrate, surface polarity, mechanical long-term stability in water, and ability to form metal complexes was inserted by the choice of suitable comonomers. The monomer 2-acetoacetoxy ethyl methacrylate (AAMA) was used as complexing unit to produce copper(II) complexes in the coating's upper surface layer. The semifluorinated monomer 1H,1H,2H,2H-perfluorodecyl methacrylate was employed to adjust the surface polarity and wettability. Comprehensive surface characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and contact angle measurements showed that surface compositions and properties can be easily adjusted by varying the concentrations of the comonomers. The formation of copper(II) complexes along the copolymer chains and their stability against washing out with plenty of water was proven by XPS. Copolymers containing semifluorinated comonomers significantly inhibited the growth of Achnanthidium species. Copolymers with copper-loaded AAMA-sequences were able to reduce both the growth of Achnanthidium spec. and Staphylococcus aureus.

  17. Methacrylate based gel polymer electrolyte for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Isken, P.; Winter, M.; Passerini, S.; Lex-Balducci, A.

    2013-03-01

    A methacrylate based gel polymer electrolyte (GPE) was prepared and electrochemically investigated. The polymer was synthesized as a statistical co-polymer of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) and benzyl methacrylate (BnMA) by free radical polymerization. The ethylene glycol side chain of OEGMA should be able to interact with the liquid electrolyte, thus keeping it inside the GPE, whereas BnMA was used to enhance the mechanical stability of the GPE. Such a polymer was able to retain liquid electrolyte up to 400% of its own weight, while the mechanical stability of the GPE was still high enough to be used as separator in lithium-ion batteries. The GPE displayed a conductivity of 1.8 mS cm-1 at 25 °C and an electrochemical stability window comparable to that of a standard liquid electrolyte. When used in lithium-ion batteries, such a GPE allowed a performance comparable to that obtained using conventional liquid electrolytes. Therefore the reported electrolyte was identified as a promising candidate as electrolyte for lithium-ion batteries.

  18. Evaluation of alternate routes for the synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.

    1998-12-31

    The use of coal-derived syngas to produce high value chemicals is an important means of upgrading this resource. One example of a chemical that can be produced from coal-derived syngas is methyl methacrylate (MMA). Poly-methyl methacrylate is widely used in coatings and in various industrial molded products. The most widely practiced commercial technology for the synthesis of MMA is the acetone cyanohydrin (ACH) process. This process requires handling of large quantities of toxic hydrogen cyanide and generates one mole of ammonium bisulfate waste per mole of MMA. This bisulfate must either be regenerated or discarded, either of which substantially increases the cost. The ACH technology is thus environmentally and economically untenable for any new MMA plant expansions that would be needed to meet increasing demand. The RTI-Eastman-Bechtel research team is developing an alternative, environmentally benign route to MMA consisting of three steps; (step 1) synthesis of a propionate from ethylene, carbon monoxide, and steam, (step 2) condensation of this propionate with formaldehyde, and (step 3) esterification of resulting methacrylic acid with methanol to form MMA. This paper describes the preliminary economics of the overall process compared to other emerging processes, and focuses on step 2, including long term testing of catalysts for the condensation of propionic acid with formaldehyde to form MAA.

  19. Synthesis and characterization of injectable, water-soluble copolymers of tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates.

    PubMed

    Anderson, Brian C; Mallapragada, Surya K

    2002-11-01

    Several homopolymers and copolymers of 2-(diethylamino)ethyl methacrylate (DEAEM) and poly(ethylene glycol) methyl ether methacrylate (PEGMEM) were synthesized using anionic polymerization initiated by potassium t-butoxide. The polymers were characterized by average molecular weight, polydispersity and monomeric unit composition. A very narrow molecular weight distribution was achieved with a well-controlled composition. The glass transition temperatures and compositions of the copolymers followed a Gordon-Taylor relationship. The water solubility and biocompatibility of the copolymers was compared to their parent homopolymers to determine if the addition of a poly(ethylene glycol) group was sufficient to solubilize the polymers in aqueous buffer solutions and to increase the biocompatibility of the polymers. These water-soluble, injectable cationic copolymers have potential applications in gene delivery as well as other biomaterial applications.

  20. Preparation of hydroxyapatite/poly(methyl methacrylate) and calcium silicate/poly(methyl methacrylate) interpenetrating hybrid composites.

    PubMed

    Monvisade, Pathavuth; Siriphannon, Punnama; Jermsungnern, Rapee; Rattanabodee, Sirirat

    2007-10-01

    Hydroxyapatite/poly(methyl methacrylate) (HAp/PMMA) and calcium silicate/poly(methyl methacrylate) (CS/PMMA) composites were prepared by interpenetrating bulk polymerization of methyl methacrylate (MMA) monomer in porous structures of HAp and CS. The porous HAp and CS templates were prepared by mixing their calcined powders with poly(vinyl alcohol) (PVA) solution, shaping by uniaxial pressing and then firing at 1,100 degrees C for HAp and 900 degrees C for CS. The templates were soaked in the solution mixture of MMA monomer and 0.1 mol% of benzoyl peroxide (BPO) for 24 h. The pre-composites were then bulk polymerized at 85 degrees C for 24 h under nitrogen atmosphere. The microstructures of the composites showed the interpenetrating of PMMA into the porous HAp and CS structures. Thermogravimetric analysis indicated that the PMMA content in the HAp/PMMA and CS/PMMA composites were 13 and 26 wt%, respectively. Weight average molecular weights (M(w)) of PMMA were about 491,000 for HAp/PMMA composites and about 348,000 for CS/PMMA composites. Compressive strengths of these composites were about 90-131 MPa in which they were significantly higher than their starting porous templates.