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Sample records for 2-hydroxyethyl methacrylate hema

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Model studies of diffusion-controlled (2-hydroxyethyl methacrylate) HEMA hydrogel membranes for controlled release of proteins

    NASA Astrophysics Data System (ADS)

    Appawu, Jennifer A. M.

    This thesis project consisted of three main components that were connected by roots in chemical analysis for studies in tissue engineering. The first part focused on characterizing the structural parameters of synthetic cross-linked poly (2-hydroxyethyl methacrylate) (Poly(HEMA) hydrogel membranes to determine optimal formulations for clinical studies. Poly(HEMA) membranes were loaded with Keratincocyte Growth Factor (KGF) for controlled release studies. Protein loading and release kinetics were determined with fluorescence spectroscopy. The spatial distribution of a protein in the membrane was determined using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The last part of the project focused on determining the biological effects of the polymer membranes in-vitro with a model cell line and a pilot in-vivo animal study. Based on the components completed in this project, five chapters are included in this dissertation document and are summarized below. A new protocol was developed using fluorescence spectroscopy that measured the rate of protein diffusion into cross-linked polymer membranes by measuring the change in the fluorescence intensity of the protein solution. This technique was also able to detect a conformational change that occurs within protein when KGF was imbibed within these cross-linked polymer membranes. ToF-SIMS chemical imaging and 3D depth profiling was used to determine the spatial distribution of KGF protein in frozen-hydrated HEMA hydrogel membranes. The 3D depth profiles showed that the KGF protein was aggregated in bright spots that indicated that KGF was not spatially homogenous on the surface and through the depth profiles. 3D depth profiles of the membranes studied at various times during release studies show that areas with aggregated proteins were retained during release, and at times with maximum release. The interpretation of the bright regions is that the KGf protein interacted with the cross-linked network of the

  7. 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

    2014-07-01

    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. PMID:24915233

  8. 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

  9. 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. PMID:14632691

  10. Photoinitiated chemical vapor deposition of cytocompatible poly(2-hydroxyethyl methacrylate) films.

    PubMed

    McMahon, Brian J; Pfluger, Courtney A; Sun, Bing; Ziemer, Katherine S; Burkey, Daniel D; Carrier, Rebecca L

    2014-07-01

    Poly(2-hydroxyethyl methacrylate) (pHEMA) is a widely utilized biomaterial due to lack of toxicity and suitable mechanical properties; conformal thin pHEMA films produced via chemical vapor deposition (CVD) would thus have broad biomedical applications. Thin films of pHEMA were deposited using photoinitiated CVD (piCVD). Incorporation of ethylene glycol diacrylate (EGDA) into the pHEMA polymer film as a crosslinker, confirmed via Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, resulted in varied swelling and degradation behavior. 2-Hydroxyethyl methacrylate-only films showed significant thickness loss (up to 40%), possibly due to extraction of low-molecular-weight species or erosion, after 24 h in aqueous solution, whereas films crosslinked with EGDA (9.25-12.4%) were stable for up to 21 days. These results differ significantly from those obtained with plasma-polymerized pHEMA, which degraded steadily over a 21-day period, even with crosslinking. This suggests that the piCVD films differ structurally from those fabricated via plasma polymerization (plasma-enhanced CVD). piCVD pHEMA coatings proved to be good cell culture materials, with Caco-2 cell attachment and viability comparable to results obtained on tissue-culture polystyrene. Thus, thin film CVD pHEMA offers the advantage of enabling conformal coating of a cell culture substrate with tunable properties depending on method of preparation and incorporation of crosslinking agents. PMID:23852714

  11. 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.

  12. 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.

  13. Allergic contact dermatitis from 2-hydroxyethyl methacrylate in an adhesive on an electrosurgical earthing plate.

    PubMed

    Kanerva, L; Alanko, K

    1998-01-01

    A highly (meth)acrylate-allergic patient underwent surgery because of nodular struma. Three days after her operation she developed an itching dermatitis on her left thigh. She came to our attention 18 days after the operation, because of an oozing, highly pruritic dermatitis, 8 x 19 cm in width on her left thigh, at the site where an electrosurgical earthing plate had been used during the surgery. It was revealed that the pressure-sensitive adhesive of the pad contained 2-hydroxyethyl methacrylate (2-HEMA) to which the patient earlier had had an allergic patch test reaction. The patient was negative on patch testing to other (meth)acrylates present in the pad. Patients should be questioned about possible methacrylate sensitivity before methacrylate-containing electrosurgical earthing plates are used during surgery. Allergic contact dermatitis caused by acrylic adhesives is briefly reviewed. PMID:9854170

  14. 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. PMID:24952074

  15. Biodegradability of poly (2-hydroxyethyl methacrylate) in the presence of the J774.2 macrophage cell line.

    PubMed

    Mabilleau, G; Moreau, M F; Filmon, R; Baslé, M F; Chappard, D

    2004-09-01

    The degradation of cross-linked and linear poly(2-hydroxyethyl methacrylate) (pHEMA), was examined in vitro with J774.2 cells. pHEMA microbeads were prepared with both types of polymers. Only cells in contact with the microbeads increased their production of lysosomal enzymes (TRAcP and ANAE) and released large amounts of reactive oxygen species with both types of pHEMA microbeads. Electron microscopy showed that macrophages were able to erode the surface of linear pHEMA but unable to erode the surface of the cross-linked polymer. Cells appeared wrapped by the linear pHEMA surface, but those cultured on the cross-linked polymer were only laying at the surface. After cell culture, the surface roughness of pHEMA slices was observed by atomic force microscopy (AFM). There was a significant increase in roughness (R(a)) of the surface of linear pHEMA slices cultured with J774.2 cells whereas no difference in R(a) between the surface of cross-linked pHEMA slices could be measured. AFM image of the hydrated materials were done: the surface of linear pHEMA swelled considerably in saline whereas the hydrated cross-linked polymer did not differ from the air-dried appearance. In conclusion, linear pHEMA swells in biological fluids, activates macrophages in close contact with the polymer and can be progressively eroded. PMID:15109839

  16. 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. PMID:27049528

  17. 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.

  18. 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. PMID:12164188

  19. 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

  20. Degradable poly(2-hydroxyethyl methacrylate)-co-polycaprolactone Hydrogels for Tissue Engineering Scaffolds

    PubMed Central

    Atzet, Sarah; Curtin, Scott; Trinh, Phalen; Bryant, Stephanie

    2009-01-01

    Biodegradable poly(2-hydroxyethyl methacrylate) hydrogels for engineered tissue constructs were developed using atom transfer radical polymerization (ATRP), a degradable crosslinker and a macroinitiator. Hydrogels are appropriate materials for tissue engineering scaffolds due to their tissue-like mechanical compliance and mass transfer properties. However, many hydrogels that have seen wide application in medicine are not biodegradable or cannot be easily cleared from the body. Poly(2-hydroxyethyl methacrylate) (pHEMA) was selected for the scaffold material due to its reasonable mechanical strength, elasticity, long history of successful use in medicine and because it can be easily fabricated into numerous configurations. pHEMA was studied at various molecular weights between 2 kDa and 50 kDa. The molecular weight range suitable for renal clearance was an important factor in the experimental design. The fabricated hydrogels contain oligomeric blocks of polycaprolactone (PCL), a hydrolytically and enzymatically degradable polymer, as a crosslinking agent. In addition a degradable macroinitiator also containing oligomeric PCL was used to initiate the ATRP. The chain length, crosslink density, and polymerization solvent were found to greatly affect the mechanical properties of the pHEMA hydrogels. Degradation of the pHEMA hydrogels was characterized using 0.007 M NaOH, lipase solutions and phosphate buffered saline. Mass loss, swelling ratio and tensile modulus were evaluated. Degradation products from the sodium hydroxide were measured using gel permeation chromatography (GPC) to verify the polymer lengths and polydispersity. Erosion was only observed in the sodium hydroxide and lipase solutions. However, swelling ratio and tensile modulus indicate bulk degradation in all PCL containing samples. Degradable hydrogels in enzymatic solutions showed 30% mass loss in 16 weeks. Initial cell toxicity studies indicate no adverse cellular response to the hydrogels or their

  1. Study on Cluster Formation of Poly 2-HYDROXYETHYL Methacrylate Functionalized Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Ashok Kumar, Nanjundan; Kim, Sung Hun; Kim, Jong Tae; Lim, Kwon Taek; Jeong, Yeon Tae

    Cluster-like network structures of single-walled carbon nanotubes (SWNTs) were synthesized by chemical grafting poly 2-hydroxyethyl methacrylate (polyHEMA) to the sidewalls of SWNTs. Acid chloride-functionalized tubes were coupled with commercially available HEMA monomer, which was in turn polymerized using a radical initiator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to identify the surface changes on the nanocomposites. Microscopic observations of the nanotube complexes by field emission scanning electron microscopy (FE-SEM) show that the tubes were dispersed and formed cluster-like network, branched structures with less bundling, thus, strongly suggesting a firm coating of the polymer on nanotube walls. The coating was further confirmed by transmission electron microscopy. The thermal properties of the nanotube complex as studied by thermal gravimetric analysis (TGA) revealed that coating enhanced stability of the complex, when compared to that of bulk polyHEMA and pristine SWNTs. The nanotube complexes showed excellent suspension stability when dispersed in organic solvent.

  2. 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. PMID:25632927

  3. 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.

  4. Sensitization Potential of Dental Resins: 2-Hydroxyethyl Methacrylate and Its Water-Soluble Oligomers Have Immunostimulatory Effects

    PubMed Central

    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. PMID:24312427

  5. 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. PMID:24962678

  6. Chemically modified poly(2-hydroxyethyl methacrylate) cryogel for the adsorption of heparin.

    PubMed

    La Spina, R; Tripisciano, C; Mecca, T; Cunsolo, F; Weber, V; Mattiasson, B

    2014-08-01

    Various clinical procedures, such as cardiovascular surgery or extracorporeal blood purification, involve systemic anticoagulation using heparin. High concentrations of circulating heparin require neutralization due to possible serious bleeding complications. The intravenous administration of the heparin antagonist protamine sulfate is routinely clinically performed, but is frequently associated with adverse reactions. Therefore, there is a need for a valid and safe alternative to achieve extracorporeal heparin removal from blood or plasma, such as a filter, a matrix, or an adsorbent. Here, we describe the development of a macroporous poly(2-hydroxyethyl methacrylate)-based monolithic cryogel functionalized with l-lysine (pHEMA-lys) and the characterization of its selective heparin adsorption. The maximum binding capacity was quantified in vitro using aqueous and serum solutions under static and dynamic conditions, and fresh human plasma under static conditions. The pHEMA-lys bound 40,500 IU and 32,500 IU heparin/g cryogel at the equilibrium in aqueous solution and 50% serum, respectively. In human plasma spiked with 100 IU/mL of heparin, the binding was still highly efficient (4330 IU/g cryogel after 30 min, i.e., 87% of the initial concentration). The cryogels showed good blood compatibility, as indicated by negligible adsorption of albumin, antithrombin III, and total protein, and may thus be suitable for extracorporeal heparin removal. PMID:24425361

  7. Degradable poly(2-hydroxyethyl methacrylate)-co-polycaprolactone hydrogels for tissue engineering scaffolds.

    PubMed

    Atzet, Sarah; Curtin, Scott; Trinh, Phalen; Bryant, Stephanie; Ratner, Buddy

    2008-12-01

    Biodegradable poly(2-hydroxyethyl methacrylate)(pHEMA) hydrogels for engineered tissue constructs were developed by the use of atom transfer radical polymerization (ATRP), a degradable cross-linker, and a macroinitiator. Hydrogels are appropriate materials for tissue engineering scaffolds because of their tissue-like mechanical compliance and mass transfer properties. However, many hydrogels that have seen wide application in medicine are not biodegradable or cannot be easily cleared from the body. pHEMA was selected for the scaffold material because of its reasonable mechanical strength, elasticity, and long history of successful use in medicine as well as because it can be easily fabricated into numerous configurations. pHEMA was studied at various molecular weights between 2 and 50 kDa. The molecular weight range suitable for renal clearance was an important factor in the experimental design. The fabricated hydrogels contain oligomeric blocks of polycaprolactone (PCL), a hydrolytically and enzymatically degradable polymer, as a cross-linking agent. In addition, a degradable macroinitiator that also contained oligomeric PCL was used to initiate the ATRP. The chain length, cross-link density, and polymerization solvent were found to affect the mechanical properties of the pHEMA hydrogels. Degradation of the pHEMA hydrogels was characterized by the use of 0.007 M NaOH, lipase solutions, and phosphate-buffered saline. The mass loss, swelling ratio, and tensile modulus were evaluated. Degradation products after sodium hydroxide treatment were measured by the use of gel permeation chromatography (GPC) to verify the polymer lengths and polydispersity. Erosion was observed in only the sodium hydroxide and lipase solutions. However, the swelling ratio and tensile modulus indicate bulk degradation in all PCL-containing samples. Degradable hydrogels in enzymatic solutions showed 30% mass loss in 16 weeks. Initial cell toxicity studies indicate no adverse cellular response

  8. 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.

  9. Narrowly size-distributed cobalt salt containing poly(2-hydroxyethyl methacrylate) particles by inverse miniemulsion.

    PubMed

    Cao, Zhihai; Wang, Zhuo; Herrmann, Christine; Ziener, Ulrich; Landfester, Katharina

    2010-05-18

    Cobalt-containing hybrid particles have been prepared through the encapsulation of cobalt tetrafluoroborate hexahydrate (CoTFB) via inverse miniemulsion polymerization of 2-hydroxyethyl methacrylate (HEMA). We systematically varied the amount and type of cosolvent (water, methanol, ethanol, ethylene glycol), apolar continuous phase (cyclohexane, isooctane, isopar M, hexadecane), amount of cobalt salt, and molecular weight of the polymeric surfactant. The influence of those parameters on the particle size, size distribution, and particle morphology were investigated. Narrowly size-distributed hybrid particles with good colloidal stability could be obtained in a wide range of cobalt content between 5.7 and 22.6 wt % salt relative to the monomer. The addition of a cosolvent such as water not only promotes the loading of metal salt but also has a positive influence on narrowing the particle size distribution. We assume that generally narrowly size-distributed particles can be obtained for a large variety of combinations of polar/apolar phase by adjusting the balance between osmotic and Laplace pressure via the solubility of the metal salt in the continuous phase and lowering the interfacial tension by adjusting the hydrophilic-lipophilic balance (HLB) value of the surfactant. The results show a significant advantage of the inverse miniemulsion over the direct system with respect to the variability and total amount of metal salt without losing the narrow particle size distribution and colloidal stability. PMID:20112941

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

    PubMed

    Bilgic, Tugba; Klok, Harm-Anton

    2015-11-01

    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. PMID:26441148

  11. Investigation of bonding properties of denture bases to silicone-based soft denture liner immersed in isobutyl methacrylate and 2-hydroxyethyl methacrylate

    PubMed Central

    Tugut, Faik; Mutaf, Burcu; Guney, Umit

    2014-01-01

    PURPOSE The purpose of this study was to investigate the bonding properties of denture bases to silicone-based soft denture liners immersed in isobutyl methacrylate (iBMA) and 2-hydroxyethyl methacrylate (HEMA) for various lengths of time. MATERIALS AND METHODS Polymethyl methacrylate (PMMA) test specimens were fabricated (75 mm in length, 12 mm in diameter at the thickest section, and 7 mm at the thinnest section) and then randomly assigned to five groups (n=15); untreated (Group 1), resilient liner immersed in iBMA for 1 minute (Group 2), resilient liner immersed in iBMA for 3 minutes (Group 3), resilient liner immersed in HEMA for 1 minute (Group 4), and resilient liner immersed in HEMA for 3 minutes (Group 5). The resilient liner specimens were processed between 2 PMMA blocks. Bonding strength of the liners to PMMA was compared by tensile test with a universal testing machine at a crosshead speed of 5 mm/min. Data were evaluated by 1-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (α=0.05). RESULTS The highest mean value of force was observed in Group 3 specimens. The differences between groups were statistically significant (P<.05), except between Group 1 and Group 4 (P=.063). CONCLUSION Immersion of silicone-based soft denture liners in iBMA for 3 minutes doubled the tensile bond strength between the silicone soft liner and PMMA denture base materials compared to the control group. PMID:24843397

  12. 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.

  13. 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. PMID:23910267

  14. 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. PMID:24268266

  15. 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 Central

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

    2009-01-01

    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-κB in the cells, since HEMA mediated inhibition of nuclear NF-κB expression and function was significantly blocked in the presence of NAC treatment. Moreover, blocking of nuclear translocation of NF-κB in oral keratinocytes sensitized these cells to HEMA mediated apoptosis. In addition, since NAC was capable of rescuing close to 50% of NF-κB knockdown cells from HEMA mediated cell death, there is, therefore, an NF-κB independent pathway of protection from HEMA mediated cell death by NAC. NAC mediated prevention of HEMA induced cell death in NF-κB 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-κB knockdown cell function significantly. Therefore, NAC protects oral keratinocytes from the toxic effects of HEMA through NF-κB dependent and independent pathways. Moreover, our data suggest the potential involvement of JNK pathway in NAC mediated protection. PMID:19176594

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. Synthesis, physical characterization, and biological performance of sequential homointerpenetrating polymer network sponges based on poly(2-hydroxyethyl methacrylate).

    PubMed

    Lou, X; Vijayasekaran, S; Chirila, T V; Maley, M A; Hicks, C R; Constable, I J

    1999-12-01

    A limitation in the use of hydrophilic poly(2-hydroxyethyl methacrylate) (PHEMA) sponges as implantable devices is their inherently poor mechanical strength. This precludes proper surgical manipulation, especially in the eye where the size of the implant is usually small. In this study a new method was developed to produce mechanically stronger PHEMA sponges. Sequential homointerpenetrating polymer network (homo-IPN) sponges were made by using HEMA as the precursor for generating both the first network and the successive interpenetrated networks. Following the formation of network I, the sponge was squeezed to remove the interstitial water, soaked in the second monomer (also HEMA), and squeezed again to remove the excess monomer from the pores before being subjected to the second polymerization leading to the formation of network II. Two two-component IPN sponges (K2 and K4) with increasing HEMA content in the network II and a three-component IPN sponge (K3) were produced, and their properties were compared to those of a homopolymer PHEMA sponge (control). Apart from elongation, the tensile properties were all significantly enhanced in the IPN sponges; the water content was the same as in the control sponge, except for sponge K4, which was lower. Light microscopy revealed similar pore morphologies of the control and IPN sponges K2 and K3, and the majority of the pores were around 25 microm. Sponge K4 displayed smaller pores of around 10 microm. Cellular invasion into the sponges was examined in vitro (incubation with 3T3 fibroblasts) and in vivo (implantation in rabbit corneas). Although the in vitro assay detected a change in the cell behavior in the early stage of invasion, which was probably due to the formation of IPNs, such changes were not reflected in the longer term in vivo experiment. There was a proper integration of sponges K2 and K3 with the corneal stroma, but much less cellular invasion and no neovascularization in sponge K4. We concluded that IPN

  1. 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. PMID:25203908

  2. Preparation of well-defined poly(2-hydroxyethyl methacrylate) macromonomers via atom transfer radical polymerization.

    PubMed

    Yang, Pengcheng; Armes, Steven P

    2014-01-01

    A series of six near-monodisperse methacrylic macromonomers is prepared via atom transfer radical polymerization (ATRP) of 2-hydroxyethyl methacrylate using a tertiary amine-functionalized initiator at 50 °C, followed by quaternization with excess 4-vinylbenzyl chloride at 20 °C. GPC analyses indicate polydispersities of around 1.20 and their mean degrees of polymerization (DP) range from 20 to 70, as judged by both (1) H NMR and UV spectroscopy. The former technique is more convenient but the latter proved more accurate for the higher DP values, provided that an appropriate model compound is utilized for calibration. Finally, these new macromonomers are used to prepare sterically stabilized polystyrene latexes with relatively narrow size distributions via alcoholic dispersion polymerization. PMID:24123461

  3. 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.

  4. 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. PMID:24862905

  5. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Modified methyl methacrylate, 2... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10153 Modified methyl methacrylate, 2... reporting. (1) The chemical substance identified generically as modified methyl methacrylate,...

  6. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Modified methyl methacrylate, 2... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10153 Modified methyl methacrylate, 2... reporting. (1) The chemical substance identified generically as modified methyl methacrylate,...

  7. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Modified methyl methacrylate, 2... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10153 Modified methyl methacrylate, 2... reporting. (1) The chemical substance identified generically as modified methyl methacrylate,...

  8. 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...

  9. 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...

  10. 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.

  11. 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

  12. 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

    2015-01-01

    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

  13. 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.

  14. 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.

  15. 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

  16. Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) studied by temperature-dependent infrared spectroscopy

    PubMed Central

    Morita, Shigeaki

    2014-01-01

    Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated by means of temperature-dependent infrared (IR) spectroscopy. Spectral variations involved with the OH…OH and C=O…HO types of hydrogen-bonds were found around the glass transition temperature of 80°C. Hydrogen-bonds among the hydroxyl groups gradually dissociate with increasing temperature. In contrast, discontinuous variation in the carbonyl bands was observed around the glass transition temperature. An association of the C=O…HO type of hydrogen-bond with increasing temperature above the glass transition temperature was revealed. These were concluded from the present study that hydrogen-bonds among the hydroxyl groups in each side chain terminal suppress the main chain mobility in the polymer matrix below the glass transition temperature, while the dissociation of the OH…OH type of hydrogen-bonds induces the association of the C=O…HO type of hydrogen-bond. As a result, the mobility of the main chain is induced by the change in hydrogen-bonds structure at the glass transition temperature. PMID:24790979

  17. 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.

  18. Hydrogen-Bonds Structure in Poly(2-Hydroxyethyl Methacrylate) Studied by Temperature-Dependent Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Morita, Shigeaki

    2014-03-01

    Hydrogen-bonds structure in poly(2-hydroxyethyl methacrylate) (PHEMA) were investigated by means of temperature-dependent infrared (IR) spectroscopy. Spectral variations involved with the OH•••OH and C=O•••HO types of hydrogen-bonds were found around the glass transition temperature of 80 °C. Hydrogen-bonds among the hydroxyl groups gradually dissociate with increasing temperature. In contrast, discontinuous variation in the carbonyl bands was observed around the glass transition temperature. An association of the C=O•••HO type of hydrogen-bond with increasing temperature above the glass transition temperature was revealed. These were concluded from the present study that hydrogen-bonds among the hydroxyl groups in each side chain terminal suppress the main chain mobility in the polymer matrix below the glass transition temperature, while the dissociation of the OH•••OH type of hydrogen-bonds induces the association of the C=O•••HO type of hydrogen-bond. As a result, the mobility of the main chain is induced by the change in hydrogen-bonds structure at the glass transition temperature.

  19. Evaluation of porous networks of poly(2-hydroxyethyl methacrylate) as interfacial drug delivery devices.

    PubMed

    Dziubla, T D; Torjman, M C; Joseph, J I; Murphy-Tatum, M; Lowman, A M

    2001-11-01

    Long-term implantable drug delivery devices are desirable to achieve rapid and reliable delivery of bioactive substances to the body. The limitation of most implantable devices is the resulting chronic inflammatory response and fibrous encapsulation of the implant, which prevents effective drug delivery for prolonged periods. One method of overcoming this problem is the addition of an intermediary that could prevent capsule formation. Biocompatible materials with interconnected pore structures greater than 8-10 microm have been shown to support the ingrowth and maintenance of vascularized tissue. In this investigation, we evaluate the efficacy of using porous hydrogel sponges for the tissue interface in an implantable drug delivery device. Porous networks of poly(2-hydroxyethyl methacrylate) (PHEMA) were synthesized using a thermally initiated free-radical solution polymerization. To characterize the microstructure of the PHEMA networks, scanning electron microscopy and mercury porosimetry were used. By altering the solvent fraction in the reaction mixture, PHEMA sponges were synthesized with interconnected pores ranging in size from from 6 to 15 microm with porosities of 55% to 87%. Following the in vitro evaluation, sponges were attached to the distal end of a 20-gauge catheter tubing, and implanted subcutaneously and intraperitoneally. After 5 months implantation, insulin was infused into the devices from external pumps and rapid insulin absorption was observed in conjunction with dramatic lowering of blood glucose levels. From histological evaluation of explanted devices, we observed highly vascularized tissue surrounding the mesenteric implants. These results indicate that it may be possible to use PHEMA sponges for a tissue intermediary for long-term implantable drug delivery devices. PMID:11561895

  20. Tuning the concentration of dye loaded polymer films for maximum photosensitization efficiency: phloxine B in poly(2-hydroxyethyl methacrylate).

    PubMed

    Litman, Yair; Rodríguez, Hernán B; San Román, Enrique

    2016-01-01

    Fluorescence and singlet molecular oxygen ((1)O2) quantum yields for phloxine B loaded poly(2-hydroxyethyl methacrylate) thin films are determined at dye concentrations from 0.015 to 22 wt%. Fluorescence self-quenching and the fall off of the (1)O2 quantum yield observed above 0.1 wt% are attributed to very weakly interacting close-lying dye molecules acting as energy traps arising from molecular confinement. The maximum singlet oxygen generation efficiency (quantum yield × absorption factor) lies at concentrations around 2 wt%, where fluorescence self quenching amounts to more than 80%. Data are fitted quantitatively by using a quenching radius model involving energy migration and trapping with rQ = 1.2 nm. The present results constitute a proof of concept for the rational design of heterogeneous photosensitizers in general and, particularly, for applications in which the antimicrobial activity of singlet oxygen is central. PMID:26661564

  1. Solid-state lasers based on copolymers of methyl methacrylate and 2-hydroxyethyl acrylate doped with pyrromethene 567 dye

    NASA Astrophysics Data System (ADS)

    Chen, D. Y.; Jiang, Y. G.; Fan, R. W.; Peng, H.; Xia, Y. Q.

    2009-05-01

    Solid-state dye laser samples based on copolymers of methyl methacrylate (MMA) and 2-hydroxyethyl acrylate (HEA) doped with pyrromethene 567(PM567) were prepared. The highest slope efficiency 46.4% was obtained. With pump repetition rate of 10 Hz and intensity of 0.1 J/cm2, the output energy of the sample based on P (MMA: HEA 16:4) remained up to 82.10% of its initial value after approximate 100000 shots. To our knowledge, the achieved photostability is the best under the same condition so far. Compared with the sample based on the monopolymer, the slope efficiency and photostability of copolymer-based solid-state dye samples were both enhanced. The results indicate that the high laser performance using solid-state dye samples based on copolymers of MMA with HEA as solid hosts can be achieved.

  2. Nonvolatile memory characteristics of organic thin film transistors using poly(2-hydroxyethyl methacrylate)-based polymer multilayer dielectric

    NASA Astrophysics Data System (ADS)

    Chen, Ying-Chih; Su, Yan-Kuin; Yu, Hsin-Chieh; Huang, Chun-Yuan; Huang, Tsung-Syun

    2011-10-01

    A wide hysteresis width characteristic (memory window) was observed in the organic thin film transistors (OTFTs) using poly(2-hydroxyethyl methacrylate) (PHEMA)-based polymer multilayers. In this study, a strong memory effect was also found in the pentacene-based OTFTs and the electric characteristics were improved by introducing PHEMA/poly(methyl methacrylate) (PMMA)/PHEMA trilayer to replace the conventional PHEMA monolayer or PMMA/PHEMA and PHEMA/PMMA bilayer as the dielectric layers of OTFTs. The memory effect was originated from the electron trapping and slow polarization of the dielectrics. The hydroxyl (-OH) groups inside the polymer dielectric were the main charge storage sites of the electrons. This charge-storage phenomenon could lead to a wide flat-band voltage shift (memory window, △VFB = 22 V) which is essential for the OTFTs' memory-related applications. Moreover, the fabricated transistors also exhibited significant switchable channel current due to the charge-storage and slow charge relaxation.

  3. T-style keratoprosthesis based on surface-modified poly (2-hydroxyethyl methacrylate) hydrogel for cornea repairs.

    PubMed

    Xiang, Jun; Sun, Jianguo; Hong, Jiaxu; Wang, Wentao; Wei, Anji; Le, Qihua; Xu, Jianjiang

    2015-05-01

    Corneal disease is a common cause of blindness, and keratoplasty is considered as an effective treatment method. However, there is a severe shortage of donor corneas worldwide. This paper presents a novel T-style design of a keratoprosthesis and its preparation methods, in which a mechanically and structurally effective artificial cornea is made based on a poly(2-hydroxyethyl methacrylate) hydrogel. The porous skirt was modified with hyaluronic acid and cationized gelatin, and the bottom of the optical column was coated with poly(ethylene glycol). The physical properties of the T-style Kpro were analyzed using ultraviolet and visible spectrophotometry and electron scanning microscopy. The surface chemical properties were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface modification in the spongy skirt promoted cell adhesion and produced a firm bond between the corneal tissue and the implant device, while the surface modification in the optic column resisted cell adhesion and prevented retroprosthetic membrane formation. Through improved surgical techniques, the novel T-style keratoprosthesis provides enough mechanical stability to facilitate long-term biointegration with the host environment. In vivo implantation experiments showed that the T-style keratoprosthesis is a promising cornea alternative for patients with severe limbal stem cell deficiency and corneal opacity. PMID:25746271

  4. Facile synthesis of ZnO-poly(2-hydroxyethyl methacrylate) nanocomposites by surface-initiated ARGET atom transfer radical polymerization.

    PubMed

    Mai, Thanh Binh; Tran, Thi Nga; Bach, Long Giang; Kim, Dong Woo; Park, Jong Myung; Lim, Kwon Taek

    2014-11-01

    The covalent attachment of poly(2-hydroxyethyl methacrylate) on ZnO nanoparticles (NPs) has been achieved by ARGET ATRP. The polymer chains were grown from the surface of ATRP-initiator modified ZnO NPs with a copper (II) catalyst under activation of zerovalent copper as a reducing agent. FT-IR, FE-SEM, TEM and TGA were employed for the characterization of the nanocomposites. GPC was used to determine the molecular weight and PDI of the cleaved polymer. The covalent attachment of polymer chains onto the surface of ZnO NPs was sufficiently confirmed by FT-IR. In addition, the formation of the polymer encapsulating ZnO cores was demonstrated from TEM and SEM images. It was found that the growing of polymer brushes from the ZnO surface could be induced even though the catalyst amount was reduced to 10 ppm without loss of inherent control manner. This report contributed to demonstrate the versatility and feasibility of ATRP-based surface-initiated polymerization for the preparation of inorganic/polymer nanocomposites. PMID:25958609

  5. 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.

  6. Streptavidin-modified monodispersed magnetic poly(2-hydroxyethyl methacrylate) microspheres as solid support in DNA-based molecular protocols.

    PubMed

    Salih, Tagrid; Ahlford, Annika; Nilsson, Mats; Plichta, Zdeněk; Horák, Daniel

    2016-04-01

    Molecular diagnostics may provide tailored and cost efficient treatment for infectious disease and cancer. Rolling circle amplification (RCA) of padlock probes guarantees high specificity to identify nucleic acid targets down to single nucleotide resolution in a multiplex fashion. This makes the assay suitable for molecular analysis of various diseases, and interesting to integrate into automated devices for point-of-care analysis. A critical prerequisite for many molecular assays is (i) target-specific isolation from complex clinical samples and (ii) removal of reagents, inhibitors and contaminants between reaction steps. Efficient solid supports are therefore essential to enable multi-step, multi-analyte protocols. Superparamagnetic micro- and nanoparticles, with large surface area and rapid liquid-phase kinetics, are attractive for multi-step protocols. Recently, streptavidin-modified magnetic monodispersed poly(2-hydroxyethyl methacrylate) (STV-mag.PHEMA) microspheres were developed by multiple swelling polymerization. They are easily separated by a magnet and exhibit low non-specific protein sorption. In this study, the performance and the binding efficiency of STV-mag.PHEMA was addressed by circle-to-circle amplification (C2CA). A lower number of RCA products were detected as compared to the gold standard Dynabeads. Nevertheless, this study was the first to successfully adapt STV-mag.PHEMA microspheres as solid support in a DNA-based protocol, which is an important finding. The STV-mag.PHEMA microspheres were larger with about 16 times less surface area as compared to the Dynabeads, which might partly explain the lower rolling circle product (RCP) count obtained. Further research is currently ongoing comparing particles of similar sizes and optimizing reaction conditions to establish their full utility in the field. Ultimately, low cost and versatile particles are a great resource to facilitate future clinical molecular diagnostics. PMID:26838862

  7. Immobilization of glucoamylase on polymer surface by radiation-induced polymerization of glass-forming monomers at low temperatures. [Gamma radiation; 2-hydroxyethyl methacrylate; diethylene glycol dimethacrylate

    SciTech Connect

    Yoshida, M.; Kaetsu, I.

    1981-02-01

    Glucoamylase was immobilized in hydrophilic porous poly(2-hydroxyethyl methacrylate) (PHEMA) and hydrophobic microsphere poly(diethylene glycol dimethyacrylate) (PDGDA) by radiation-induced polymerization at low temperatures, in the presence of acetate buffer solution. The distribution on the matrix of immobilized glucoamylase was investigated using fluorescein isothiocyanate (FITC)-conjugated glucoamylase and the fluorescence microscope. It was found that in the porous PHEMA system, the FITC-conjugated glucoamylase is present mainly on the interface between polymer membrane and pore structure and partly in the polymer, while in the microsphere PDGDA system the immobilized glucoamylase is present merely on the surface of the polymer microsphere.

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

    PubMed Central

    Subramanian, Kaliappa gounder; Vijayakumar, Vediappan

    2011-01-01

    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. PMID:23960799

  9. Fibroblast adhesion on ECM-derived peptide modified poly(2-hydroxyethyl methacrylate) brushes: ligand co-presentation and 3D-localization.

    PubMed

    Desseaux, Solenne; Klok, Harm-Anton

    2015-03-01

    Polymer brushes prepared via surface-initiated polymerization of 2-hydroxyethyl methacrylate are powerful platforms for the fabrication of model biointerfaces to study cell-substrate interactions. In this manuscript, the versatility of surface-initiated polymerization and the poly(2-hydroxyethyl methacrylate) (PHEMA) polymer brush platform are used to address two fundamental questions, viz. the effects of ligand co-presentation and of the 3D localization of biochemical cues on cell behavior. Using a series of PHEMA brushes that present RGD and PHSRN ligands in various relative surface concentrations, the present study unequivocally demonstrates that: (i) co-presentation of PHSRN cues on an RGD functionalized substrate enhances cell adhesion and (ii) this synergetic effect is highest when the two ligands are presented at equal surface concentrations. In the second part of this study, adhesion of 3T3 fibroblasts on a series of PHEMA brushes that present the RGD ligand at a distance of 12, 23 or 42 nm away from the cell substrate interface is investigated. While cells were found to adhere to surfaces that presented the cell adhesive peptides at distances up to 23 nm from the interface, polymer brushes that contained the RGD ligands 42 nm away from the interface did not support cell adhesion. PMID:25617123

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

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    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.

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

    PubMed

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

    2015-09-01

    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). PMID:25919328

  12. 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. PMID:26222398

  13. Optimizing the release process and modelling of in vitro release data of cis-dichlorodiamminoplatinum (II) encapsulated into poly(2-hydroxyethyl methacrylate) nanocarriers.

    PubMed

    Gupta, Meher Kanta; Bajpai, Jaya; Bajpai, Anil Kumar

    2016-01-01

    Drug encapsulated nanocarriers are vehicles to transport the drug molecules and release them at the immediate vicinity of the diseased sites. The aim of this study was to design poly (2-hydroxyethyl methacrylate) nanoparticles (PHEMANPs) as a swelling and diffusion controlled drug release system for achieving sustained release of (cis-dichlorodiamminoplatinum II) CDDP. The study undertakes designing and characterization of nanocarriers, optimization of drug encapsulation, and investigating release dynamics of the CDDP drug. PHEMANPs were prepared by suspension polymerization method followed by post loading of the CDDP onto the nanocarriers. The physicochemical and biopharmaceutical properties were evaluated by FTIR, TEM, FESEM, EDX, DLS, surface charge, water intake studies, in vitro cytotoxicity, protein adsorption and percent haemolysis. Chemical stability of the drug was assessed and in vitro release experiments were performed to optimize formulation by UV spectral analysis. The obtained cumulative release data were fitted to zero, first and Korsmeyer-Peppas kinetic models to gain insights into release kinetics and prevailing drug transport mechanisms. The successful encapsulation of CDDP was achieved in different PHEMANP formulations with maximum drug encapsulation efficiency of approx. 60% and the release kinetics was found to follow the Korsmeyer-Peppas model having non-Fickian mechanism. The results indicated that the CDDP can be formulated with a high payload of PHEMANPs which can serve as promising nanomedicine and help in achieving sustained delivery of drug for targeting tumour. PMID:26478380

  14. Effect of multipurpose solutions for contact lens care on the in vitro drug-induced spoliation of poly(2-hydroxyethyl methacrylate) in simulated aqueous humour.

    PubMed

    Chirila, Traian V; Morrison, David A; Gridneva, Zoya; Meyrick, Danielle; Hicks, Celia R; Webb, John M

    2005-03-01

    Drug-induced spoliation of hydrogels as contact lenses or as implants in the anterior eye is a frequent occurrence in clinical practice. This study explores the capacity of three commercial multipurpose solutions for contact lens care to reduce the spoliation of poly(2-hydroxyethyl methacrylate) (PHEMA) specimens exposed to a simulated aqueous humour formulation and to three topical drugs commonly administered after insertion of artificial corneas (Predsol, Optimol and Depo-Ralovera). ReNu MultiPlus (Bausch & Lomb), Complete Blink-N-Cleantrade mark Lens Drops (Allergan) and Complete Protein Remover Tablets dissolved in Complete ComfortPLUS (both from Allergan) were evaluated. All multipurpose solutions were able to dislodge passively the deposits formed on hydrogels in the simulated aqueous and in the presence of Predsol and Optimol, but none were effective against the deposits induced by Depo-Ralovera. A reduction of the calcium content in deposits caused by Predsol and Optimol was confirmed after treatment with the protein remover preparation, while the other multipurpose solutions caused the complete removal of the deposits. In experiments designed to evaluate the preventive action of the multipurpose solutions, no such effects were observed regardless of the drug involved. The prospect of using multipurpose solutions as eye drops following implantation of a hydrogel artificial cornea is a valid alternative for reducing device spoliation, however it appears to depend on the nature of the postoperative medication. PMID:16318831

  15. Poly(2-hydroxyethyl methacrylate) grafted halloysite nanotubes as a molecular host matrix for luminescent ions prepared by surface-initiated RAFT polymerization and coordination chemistry

    NASA Astrophysics Data System (ADS)

    Islam, Md. Rafiqul; Bach, Long Giang; Lim, Kwon Taek

    2013-07-01

    A fluorescent nanohybrid complex comprising of halloysite nanotubes (HNTs), poly(2-hydroxyethyl methacrylate) (PHEMA), and europium ions (Eu3+) was synthesized by the combination of surface-initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization and coordination chemistry. Initially, PHEMA was grafted from the HNTs by SI-RAFT and then reacted with succinic anhydride to provide carboxyl acid groups on the external layers of HNTs-g-PHEMA nanohybrids. The subsequent coordination of the nanohybrids with Eu3+ ions afforded photoluminescent Eu3+ tagged HNTs-g-PHEMA nanohybrid complexes (HNTs-g-PHEMA-Eu3+). The structure, morphology, and fluorescence properties of the Eu3+ coordinated nanohybrid complexes were investigated by respective physical and spectral studies. FT-IR, XPS, and EDS analyses suggested the formation of the HNTs-g-PHEMA-Eu3+ nanohybrids. FE-SEM images indicated the immobilization of polymer layers on HNTs. TGA scans further demonstrated the grafting of PHEMA onto HNTs surface. The optical properties of HNTs-g-PHEMA-Eu3+ nanohybrid complexes were investigated by photoluminescence spectroscopy.

  16. A New Crosslinkable Oxygen Sensor Covalently Bonded into Poly(2-hydroxyethyl methacrylate)-CO-Polyacrylamide Thin Film for Dissolved Oxygen Sensing

    PubMed Central

    Tian, Yanqing; Shumway, Bradley R.; Meldrum, Deirdre R.

    2010-01-01

    A new oxygen sensor, compound 2, was synthesized through a chemical modification of a popularly used oxygen sensor of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP). The new sensor compound 2 possesses four crosslinkable methacrylate functional moieties, enabling it to be polymerized and crosslinked with other monomers for polymer sensing film (also called membrane) preparation. Using this characteristic, compound 2 was covalently bonded to hydrophilic poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (referred to as PHEMA to simplify) and hydrophobic polystyrene (PS) films. To better understand the advantages and disadvantages of chemical crosslinking approaches and the influence of polymer matrices on sensing performance, PtTFPP was physically incorporated into the same PHEMA and PS matrices to compare. Response to dissolved oxygen (DO), leaching of the sensor molecules from their matrices, photostability of the sensors, and response time to DO changes were studied. It was concluded that the chemical crosslinking of the sensor compound 2 in polymer matrices: (i) alleviated the leaching problem of sensor molecules which usually occurred in the physically doped sensing systems and (ii) significantly improved sensors’ photostability. The PHEMA matrix was demonstrated to be more suitable for oxygen sensing than PS, because for the same sensor molecule, the oxygen sensitivity in PHEMA film was higher than that in PS and response time to DO change in the PHEMA film was faster than that in PS. It was the first time oxygen sensing films were successfully prepared using biocompatible hydrophilic PHEMA as a matrix, which does not allow leaching of the sensor molecules from the polymer matrix, has a faster response to DO changes than that of PS, and does not present cytotoxicity to human lung adenocarcinoma epithelial cells (A549). It is expected that the new sensor compound 2 and its similar compounds with chemically crosslinking

  17. Macroporous hydrogels based on 2-hydroxyethyl methacrylate. Part 4: growth of rat bone marrow stromal cells in three-dimensional hydrogels with positive and negative surface charges and in polyelectrolyte complexes.

    PubMed

    Lesný, P; Prádný, M; Jendelová, P; Michálek, J; Vacík, J; Syková, E

    2006-09-01

    The growth of bone marrow stromal cells was assessed in vitro in macroporous hydrogels based on 2-hydro- xyethyl methacrylate (HEMA) copolymers with different electric charges. Copolymers of HEMA with sodium methacrylate (MA(-)) carried a negative electric charge, copolymers of HEMA with [2-(methacryloyloxy)ethyl] trimethylammonium chloride (MOETA(-)) carried a positive electric charge and terpolymers of HEMA, MA(-) and MOETA(+) carried both, positive and negative electric charges. The charges in the polyelectrolyte complexes were shielded by counter-ions. The hydrogels had similar porosities, based on a comparison of their diffusion parameters for small cations as measured by the real-time tetramethylammonium iontophoretic method of diffusion analysis. The cell growth was studied in the peripheral and central regions of the hydrogels at 2 hours and 2, 7, 14 and 28 days after cell seeding. Image analysis revealed the highest cellular density in the HEMA-MOETA(+) copolymers; most of the cells were present in the peripheral region of the hydrogels. A lower density of cells but no difference between the peripheral and central regions was observed in the HEMA-MA(-) copolymers and in polyelectrolyte complexes. This study showed that positively charged functional groups promote the adhesion of cells. PMID:16932865

  18. Microdynamics mechanism of D2O absorption of the poly(2-hydroxyethyl methacrylate)-based contact lens hydrogel studied by two-dimensional correlation ATR-FTIR spectroscopy.

    PubMed

    Su, Gehong; Zhou, Tao; Zhang, Yanyan; Liu, Xifei; Zhang, Aiming

    2016-01-28

    A good understanding of the microdynamics of the water absorption of poly(2-hydroxyethyl methacrylate) (PHEMA)-based contact lens is significant for scientific investigation and commercial applications. In this study, time-dependent ATR-FTIR spectroscopy combined with the perturbation correlation moving-window two-dimensional (PCMW2D) technique and 2D correlation analysis was used to study the microdynamics mechanism. PCMW2D revealed that D2O took 3.4 min to penetrate into the contact lens. PCMW2D also found the PHEMA-based contact lens underwent two processes (I and II) during D2O absorption, and the time regions of processes I and II are 3.4-12.4 min and 12.4-57.0 min. According to 2D correlation analysis, it was proved that process I has 5 steps, and process II has 3 steps. For process I, the first step is D2O hydrogen-bonding with "free" C[double bond, length as m-dash]O in the side chains. The second step is the hydrogen bond generation of the O-HO-D structure between D2O and "free" O-H groups in the side chain ends. The third step is the hydrogen bond generation of D2O and the "free" C[double bond, length as m-dash]O groups close to the crosslinking points in the contact lens. The fourth and the fifth steps are the hydration of -CH3 and -CH2- groups by D2O, respectively. For process II, the first step is the same as that of process I. The second step is the hydrogen bonds breaking of bonded O-H groups and the deuterium exchange between D2O and O-H groups in the side chain ends. The third step is also related to the deuterium exchange, which is the hydrogen bonds regeneration between the dissociated C[double bond, length as m-dash]O groups and the new O-D. PMID:26577131

  19. HEMA inhibits migration of dental pulp stem cells

    PubMed Central

    Williams, Drake W.; Wu, Hongkun; Oh, Ju-Eun; Fakhar, Camron; Kang, Mo K.; Shin, Ki-Hyuk; Park, No-Hee; Kim, Reuben H.

    2013-01-01

    Objectives Cell migration is an important step in pulpal wound healing. Although components in the resin-based dental materials are known to have adverse effects on pulp wound healing including proliferation and mineralization, their effects on cell migration have been scarcely examined. Here, we investigated effects of 2-Hydroxyethyl methacrylate (HEMA) on migration of dental pulp stem cells (DPSC) in vitro. Methods Cell viability was assessed using MTT assay, and cell migration was evaluated using wound scratch assay and transwell migration assay at non-cytotoxic doses. Western blotting was used to examine pathways associated with migration such as focal adhesion kinase (FAK), mitogen-activated protein kinase (MAPK), and glycogen synthase kinase 3 (GSK3). Results There were no drastic changes in the cell viability below 3mM HEMA. When DPSC were treated with HEMA at 0.5, 1.0, and 2.5mM, cell migration was diminished. HEMA-treated DPSC exhibited the loss of phosphorylated focal adhesion kinase (FAK) in a dose-dependent manner. The HEMA-mediated inhibition of cell migration was associated with phosphorylation of p38 but not GSK3, ERK or JNK pathways. When we inhibited the p38 signaling pathway using a p38 inhibitor, migration of DPSC was suppressed. Conclusion HEMA inhibits migration of dental pulp cells in vitro, suggesting that poor pulpal wound healing under resin-based dental materials may be due, in part, to inhibition of cell migration by HEMA. PMID:23953290

  20. 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.

  1. Multiwalled CNT-pHEMA composite conduit for peripheral nerve repair.

    PubMed

    Arslantunali, D; Budak, G; Hasirci, V

    2014-03-01

    A nerve conduit is designed to improve peripheral nerve regeneration by providing guidance to the nerve cells. Conductivity of such guides is reported to enhance this process. In the current study, a nerve guide was constructed from poly(2-hydroxyethyl methacrylate) (pHEMA), which was loaded with multiwalled carbon nanotubes (mwCNT) to introduce conductivity. PHEMA hydrogels were designed to have a porous structure to facilitate the transportation of the compounds needed for cell nutrition and growth and also for waste removal. We showed that when loaded with relatively high concentrations of mwCNTs (6%, w/w in hydrogels), the pHEMA guide was more conductive and more hydrophobic than pristine pHEMA hydrogel. The mechanical properties of the composites were better when they carried mwCNT. Elastic modulus of 6% mwCNT loaded pHEMA was twofold higher (0.32 ± 0.06 MPa) and similar to that of the soft tissues. Electrical conductivity was significantly improved (11.4-fold) from 7 × 10(-3) Ω(-1).cm(-1) (pHEMA) to 8.0 × 10(-2) Ω(-1).cm(-1) (6% mwCNT loaded pHEMA). On application of electrical potential, the SHSY5Y neuroblastoma cells seeded on mwCNTs carrying pHEMA maintained their viability, whereas those on pure pHEMA could not, indicating that mwCNT helped conduct electricity and make them more suitable as nerve conduits. PMID:23554154

  2. Incorporation of a designed ruthenium nitrosyl in PolyHEMA hydrogel and light-activated delivery of NO to myoglobin.

    PubMed

    Halpenny, Genevieve M; Olmstead, Marilyn M; Mascharak, Pradip K

    2007-08-01

    A ruthenium nitrosyl with 4-vinylpyridine (4-vpy) as one ligand, namely, [Ru(Me2bpb)(NO)(4-vpy)](BF4) (1), has been synthesized and structurally characterized. This diamagnetic {Ru-NO}6 nitrosyl is photoactive and readily releases NO upon exposure to low-intensity (5-10 mW) UV light (quantum yield at 300 nm = 0.18). Radical-induced copolymerization of 2-hydroxyethyl methacrylate (HEMA) and ethyleneglycol dimethacrylate (EGDMA) in the presence of 1 has afforded a 1-pHEMA, a transparent hydrogel in which 1 is covalently attached to the polymer backbone. Exposure of 1-pHEMA to UV light (5-10 mW) results in rapid release of NO (detected by NO electrode) that can be delivered to biological targets such as myoglobin. The photoactivity of 1-pHEMA is strictly dependent on exposure to UV light. PMID:17616126

  3. 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. PMID:24708962

  4. 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. PMID:25891253

  5. Magnetic hydrophilic methacrylate-based polymer microspheres designed for polymerase chain reactions applications.

    PubMed

    Spanová, Alena; Horák, Daniel; Soudková, Eva; Rittich, Bohuslav

    2004-02-01

    Magnetic hydrophilic non-porous P(HEMA-co-EDMA), P(HEMA-co-GMA) and PGMA microspheres were prepared by dispersion (co)polymerization of 2-hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) or glycidyl methacrylate (GMA) in the presence of several kinds of magnetite. It was found that some components used in the preparation of magnetic carriers interfered with polymerase chain reaction (PCR). Influence of non-magnetic and magnetic microspheres, including magnetite nanoparticles and various components used in their synthesis, on the PCR course was thus investigated. DNA isolated from bacterial cells of Bifidobacterium longum was used in PCR evaluation of non-interfering magnetic microspheres. The method enabled verification of the incorporation of magnetite nanoparticles in the particular methacrylate-based polymer microspheres and evaluation of suitability of their application in PCR. Preferably, electrostatically stabilized colloidal magnetite (ferrofluid) should be used in the design of new magnetic methacrylate-based microspheres by dispersion polymerization. PMID:14698232

  6. 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. PMID:24183808

  7. Poly(HEMA-co-NBMI) monolithic cryogel columns for IgG adsorption.

    PubMed

    Uygun, Murat; Şenay, R Hilal; Avcıbaşı, Nesibe; Akgöl, Sinan

    2014-02-01

    Supermacroporous poly(2-hydroxyethyl methacrylate-co-1,5-naphthalene bismaleimide) [poly(HEMA-co-NBMI)] monolithic cryogel column was prepared by free radical cryo-copolymerization of HEMA with NBMI as a hydrophobic functional comonomer and N,N'-methylene-bisacrylamide as cross-linker directly in a plastic syringe for adsorption of albumin. The monolithic cryogel contained a continuous polymeric matrix which has interconnected pores of 10-100 μm size. Poly(HEMA-co-NBMI) cryogel was characterized by swelling studies, FTIR and scanning electron microscopy. The equilibrium swelling degree of the poly(HEMA-co-NBMI) cryogel was 10.5 g of H₂O/g dry cryogel. Poly(HEMA-co-NBMI) cryogel was used in the adsorption/desorption of IgG from aqueous solutions. The maximum amount of IgG adsorption from aqueous solution in phosphate buffer was 98.20 mg/g polymer at pH 7.0. The nonspecific adsorption of IgG onto plain poly(HEMA) cryogel was very low (2.79 g/g polymer). It was observed that IgG could be repeatedly adsorbed and desorbed with the poly(HEMA-co-NBMI) cryogel without significant loss of adsorption capacity. PMID:24233543

  8. Development and characterization of rhVEGF-loaded poly(HEMA-MOEP) coatings electrosynthesized on titanium to enhance bone mineralization and angiogenesis.

    PubMed

    De Giglio, Elvira; Cometa, Stefania; Ricci, Maria Antonietta; Zizzi, Antonio; Cafagna, Damiana; Manzotti, Sandra; Sabbatini, Luigia; Mattioli-Belmonte, Monica

    2010-01-01

    Osteointegration of titanium implants could be significantly improved by coatings capable of promoting both mineralization and angiogenesis. In the present study, a copolymeric hydrogel coating, poly-2-hydroxyethyl methacrylate-2-methacryloyloxyethyl phosphate (P(HEMA-MOEP)), devised to enhance calcification in body fluids and to entrap and release growth factors, was electrosynthesized for the first time on titanium substrates and compared to poly-2-hydroxyethyl methacrylate (PHEMA), used as a blank reference. Polymers exhibiting negatively charged groups, such as P(HEMA-MOEP), help to enhance implant calcification. The electrosynthesized coatings were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. MG-63 human osteoblast-like cell behaviour on the coated specimens was investigated by scanning electron microscopy, MTT viability test and osteocalcin mRNA detection. The ability of negatively charged phosphate groups to promote hydroxyapatite-like calcium phosphate deposition on the implants was explored by immersing them in simulated body fluid. Similar biological responses were observed in both coated specimens, while calcium-phosphorus globules were detected only on P(HEMA-MOEP) surfaces pretreated with alkaline solution. Testing of the ability of P(HEMA-MOEP) hydrogels to entrap and release human recombinant vascular endothelial growth factor, to tackle the problem of insufficient oxygen and nutrient delivery, suggested that P(HEMA-MOEP)-coated titanium prostheses could represent a multifunctional material suitable for bone restoration applications. PMID:19607946

  9. Novel synthesis of cellulose-based diblock copolymer of poly(hydroxyethyl methacrylate) by mechanochemical reaction.

    PubMed

    Ohura, Takeshi; Tsutaki, Yusaku; Sakaguchi, Masato

    2014-01-01

    The mechanical fracture of polymer produces polymeric free radical chain-ends, by which liner block copolymers have been synthesized. A diblock copolymer of microcrystalline cellulose (MCC) and poly 2-hydroxyethyl methacrylate (pHEMA) was produced by the mechanochemical polymerization under vacuum and room temperature. The fraction of pHEMA in MCC-block-pHEMA produced by the mechanochemical polymerization increased up to 21 mol% with increasing fracture time (~6 h). Then, the tacticities of HEMA sequences in MCC-block-pHEMA varied according to the reaction time. In the process of mechanochemical polymerization, cellulose could play the role of a radical polymerization initiator capable of controlling stereoregularity. PMID:24741340

  10. Experimental self-etching HEMA-free adhesive systems: cytotoxicity and degree of conversion.

    PubMed

    Barbosa, Marília Oliveira; de Carvalho, Rodrigo Varella; Demarco, Flávio Fernando; Ogliari, Fabrício Aulo; Zanchi, Cesar Henrique; Piva, Evandro; da Silva, Adriana Fernandes

    2015-01-01

    The aim of this study was to evaluate the effect of replacing 2-hydroxyethyl methacrylate (HEMA) by methacrylate surfactant monomers on the cytotoxicity and degree of conversion of two-step self-etching dentin adhesive systems. Five HEMA-free adhesive systems were tested: Bis-EMA 10, Bis-EMA 30, PEG400, PEG400UDMA, PEG1000, and a HEMA group was used as positive control. The cytotoxicity of the experimental primers, with different monomer concentrations (2 or 20 wt%), and bond resins, containing 25 wt% surfactant, was assessed using murine fibroblast cell line 3T3 and the tetrazolium assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)). The degree of conversion of the bond resins was analyzed using Fourier transform infrared spectroscopy. The data were submitted to statistical analysis using level of significance set at P < 0.05. The PEG 1000 group obtained higher cell viability in comparison with HEMA in the 2 % primer. The cell survival rate using 20 % primer showed that PEG1000 and BIS-EMA 10 were less cytotoxic than HEMA. With regard to the eluate from bond resin, the data showed that the groups BIS-EMA 10, BIS-EMA 30 and PEG400UDMA were less cytotoxic than HEMA. No statistically significant difference was found among degrees of conversion of the experimental groups and HEMA. PEG 1000, BIS-EMA 10 and 30 monomers showed the biological potential for use in new adhesive system formulations since they showed lower cytotoxicity and similar degree of conversion when compared with the HEMA-containing group. PMID:25589203

  11. Improved single-cell culture achieved using micromolding in capillaries technology coupled with poly (HEMA)

    PubMed Central

    Ye, Fang; Jiang, Jin; Chang, Honglong; Xie, Li; Deng, Jinjun; Ma, Zhibo; Yuan, Weizheng

    2015-01-01

    Cell studies at the single-cell level are becoming more and more critical for understanding the complex biological processes. Here, we present an optimization study investigating the positioning of single cells using micromolding in capillaries technology coupled with the cytophobic biomaterial poly (2-hydroxyethyl methacrylate) (poly (HEMA)). As a cytophobic biomaterial, poly (HEMA) was used to inhibit cells, whereas the glass was used as the substrate to provide a cell adhesive background. The poly (HEMA) chemical barrier was obtained using micromolding in capillaries, and the microchannel networks used for capillarity were easily achieved by reversibly bonding the polydimethylsiloxane mold and the glass. Finally, discrete cell adhesion regions were presented on the glass surface. This method is facile and low cost, and the reagents are commercially available. We validated the cytophobic abilities of the poly (HEMA), optimized the channel parameters for higher quality and more stable poly (HEMA) patterns by investigating the effects of changing the aspect ratio and the width of the microchannel on the poly (HEMA) grid pattern, and improved the single-cell occupancy by optimizing the dimensions of the cell adhesion regions. PMID:26339307

  12. Construction of paclitaxel-loaded poly (2-hydroxyethyl methacrylate)-g-poly (lactide)-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine copolymer nanoparticle delivery system and evaluation of its anticancer activity

    PubMed Central

    Ma, Xiaowei; Wang, Huan; Jin, Shubin; Wu, Yan; Liang, Xing-Jie

    2012-01-01

    Background There is an urgent need to develop drug-loaded biocompatible nanoscale packages with improved therapeutic efficacy for effective clinical treatment. To address this need, a novel poly (2-hydroxyethyl methacrylate)-poly (lactide)-1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine [PHEMA-g-(PLA-DPPE)] copolymer was designed and synthesized to enable these nanoparticles to be pH responsive under pathological conditions. Methods The structural properties and thermal stability of the copolymer was measured and confirmed by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and thermogravimetric analysis. In order to evaluate its feasibility as a drug carrier, paclitaxel-loaded PHEMA-g-(PLA-DPPE) nanoparticles were prepared using the emulsion-solvent evaporation method. Results The PHEMA-g-(PLA-DPPE) nanoparticles could be efficiently loaded with paclitaxel and controlled to release the drug gradually and effectively. In vitro release experiments demonstrated that drug release was faster at pH 5.0 than at pH 7.4. The anticancer activity of the PHEMA-g-(PLA-DPPE) nanoparticles was measured in breast cancer MCF-7 cells in vivo and in vitro. In comparison with the free drug, the paclitaxel-loaded PHEMA-g-(PLA-DPPE) nanoparticles could induce more significant tumor regression. Conclusion This study indicates that PHEMA-g-(PLA-DPPE) nanoparticles are promising carriers for hydrophobic drugs. This system can passively target cancer tissue and release drugs in a controllable manner, as determined by the pH value of the area in which the drug accumulates. PMID:22419875

  13. ²H-NMR and ¹³C-NMR study of the hydration behavior of poly(2-methoxyethyl acrylate), poly(2-hydroxyethyl methacrylate) and poly(tetrahydrofurfuryl acrylate) in relation to their blood compatibility as biomaterials.

    PubMed

    Miwa, Yuko; Ishida, Hiroyuki; Tanaka, Masaru; Mochizuki, Akira

    2010-01-01

    We recorded ²H-NMR spectra of (deuterated) water in the presence of poly(2-methoxyethyl acrylate) (PMEA), poly(2-hydroxyethyl methacrylate) (PHMEA) and poly(tetrahydrofurfuryl acrylate) (PTHFA). The observed ²H-NMR peak intensities varied substantially with water content and temperature, depending upon either strong binding to polymer surface or suppressed peaks due to freezing. Indeed, ²H-NMR signals in the presence of PHEMA were strongly dependent upon its water content, while those of hydrated PMEA and PTHFA remained unchanged even at -30°C and -20°C. The latter were considerably broadened at -50°C and -30°C, respectively, due to freezing water from the super-cooled state. As a result, the states of the water molecules in PMEA and PTHFA can be classified into three types; free, freezing bound and non-freezing water molecules. The states of the water in PHEMA depend on the water content, and the water can be classified into two types, free and non-freezing water, which exhibit rapid fluctuation and restricted mobility because of the presence of macromolecules, respectively. A kind of freezing bound water, however, should exist in PHEMA. This is also consistent with the substantially decreased ²H spin-lattice relaxation times of hydrated PHEMA as compared with those of PMEA or PTHFA. It is also interesting to note that the flexibility of bound water or polymer (PMEA > PTHFA > PHEMA) is related to a characteristic parameter for biocompatibility such as the production of TAT (thrombin-antithrombin III complex) as a marker of activation of the coagulation system. Therefore, it is naturally recognized that such differential polymer dynamics might be responsible for concomitant changes in structure and dynamics of surrounding water molecules in the vicinity of constituent polymer network. PMID:20573319

  14. Solubility parameter of poly(2-hydroxyethyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Radiolytic synthesis of Ag-poly(BIS-co-HEMA-co-IA) nanocomposites

    NASA Astrophysics Data System (ADS)

    Kačarević-Popović, Z.; Tomić, S.; Krklješ, A.; Mićić, M.; Suljovrujić, E.

    2007-08-01

    Ag-poy(BIS-co-HEMA-co-IA) nanocomposites are prepared via in situ reduction of silver salt embedded in swollen polymer gels by employing gamma irradiation. Hydrogels based on 2-hydroxyethyl methacrylate, itaconic acid and four types of poly(alkylene glycol) acrylate or methacrylate (Bisomers) were previously prepared using gamma irradiation. The nanocomposites are characterized by using UV-vis, swelling measurements and thermal analysis. Evolution of plasmon absorption detected by UV-vis spectrophotometry indicated generation of Ag nanoparticles in polymer hydrogels. Altering the structure of the hydrogels did not lead to alternation of the position of the absorption maximum. The bulk property of equilibrium swelling is dependent on the presence of the Ag nanostructures. The initial thermal stability of the polymer is slightly increased due to presence of silver as nanofiller.

  20. 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.

  1. Photocontrol over the Disorder-to-Order Transition (DOT) in Thin Film of Polystyrene-block-Poly(methyl methacrylate) Block Copolymers Containing Photodimerizable anthracene functionality

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Li, Le; Wei, Xinyu; Balazs, Anna; Matyjaszewski, Krzysztof; Russell, Thomas

    2010-03-01

    Reversible photocontrol over the disorder-to-order transition (DOT) of block copolymers can be used to fabricate defect-free, long-range ordered nanomaterials over macroscopic distances by ``photo-combing'' the microdomains. Here, we randomly copolymerized anthracene functionalities in a ``dilute'' way with 2-hydroxyethyl methacrylate as the middle block, forming deuterated polystyrene-block-poly(2-(methacryloyloxy)ethyl anthracene-9-carboxylate-random-2-hydroxyethyl methacrylate)-block-poly(methyl methacrylate) (d8-PS-b-P(9AnEMA-r-HEMA)-b-PMMA) triblock copolymers. Upon UV irradiation of a thin film of the phase-mixed triblock copolymer, photodimerization of anthracene links the junction of d8-PS and PMMA blocks and produces an artificial interface to force a phase-separation, i.e. a UV-induced DOT, as evidenced by small angle neutron scattering (SANS). Reversible photocontrol over the DOT can be achieved by taking advantage of photodimerization and photodissociation of anthracene.

  2. 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

  3. Preparation and properties of a biomaterial: HEMA grafted SBS by gamma-ray irradiation.

    PubMed

    Hsiue, G H; Yang, J M; Wu, R L

    1988-05-01

    Solvent-cast films of styrene-butadiene-styrene triblock copolymer (SBS) were synthesized and a poly(2-hydroxyethyl methacrylate) (PHEMA) layer was grafted onto these films using Co 60 gamma-ray irradiation. The IR absorption spectrum of the graft copolymer was taken and its surface morphology studied by a scanning electron microscope. The degree of grafting and the mechanical properties of SBS, SBS-g-HEMA, and PHEMA were measured. In order to study its biocompatibility, contact angle and blood clotting time experiments were performed. The degree of grafting was related to the soaking time, film thickness and total irradiation dosage. However, it levelled off at 7% when the total dosage reached 1 Mrad. It was found that the mechanical properties of SBS-g-HEMA were the same as those of SBS and were superior to those of PHEMA. The blood compatibility of SBS-g-HEMA as measured by the Lee-White clotting test was better than that of SBS and polystyrene and was quite similar to that of PHEMA. PMID:3397379

  4. 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. PMID:26061346

  5. 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. PMID:21405141

  6. Supramolecular Cross-Links in Poly(alkyl methacrylate) Copolymers and Their Impact on the Mechanical and Reversible Adhesive Properties.

    PubMed

    Heinzmann, Christian; Salz, Ulrich; Moszner, Norbert; Fiore, Gina L; Weder, Christoph

    2015-06-24

    Hydrogen-bonded, side-chain-functionalized supramolecular poly(alkyl methacrylate)s were investigated as light- and temperature-responsive reversible adhesives that are useful for bonding and debonding on demand applications. Here, 2-hydroxyethyl methacrylate (HEMA) was functionalized with 2-ureido-4[1H]pyrimidinone (UPy) via a hexamethylenediisocyanate (HMDI) linker, to create a monomer (UPy-HMDI-HEMA) that serves to form supramolecular cross-links by way of forming quadruple hydrogen bonded dimers. UPy-HMDI-HEMA was copolymerized with either hexyl methacrylate or butyl methacrylate to create copolymers comprising 2.5, 5, or 10 mol % of the cross-linker. The mechanical properties of all (co)polymers were investigated with stress-strain experiments and dynamic mechanical analysis. Furthermore, the adhesive properties were studied at temperatures between 20 and 60 °C by testing single lap joints formed with stainless steel substrates. It was found that increasing the concentration of the UPy-HMDI-HEMA cross-linker leads to improved mechanical and adhesive properties at elevated temperatures. Concurrently, the reversibility of the bond formation remained unaffected, where rebonded samples displayed the same adhesive strength as regularly bonded samples. Debonding on demand abilities were also tested exemplarily for one copolymer, which for light-induced debonding experiments was blended with a UV-absorber that served as light-heat converter. Single lap joints were subjected to a constant force and heated or irradiated with UV light until debonding occurred. The necessary debonding temperature was comparable for direct heating and UV irradiation and varied between 28 and 82 °C, depending on the applied force. The latter also influenced the debonding time, which under the chosen conditions ranged from 30 s to 12 min. PMID:26043809

  7. Activation of the Nrf2-regulated antioxidant cell response inhibits HEMA-induced oxidative stress and supports cell viability.

    PubMed

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

    2015-07-01

    Oxidative stress due to increased formation of reactive oxygen species (ROS) in target cells of dental resin monomers like 2-hydroxyethyl methacrylate (HEMA) is a major mechanism underlying the disturbance of vital cell functions including mineralization and differentiation, responses of the innate immune system, and the induction of cell death via apoptosis. Although a shift in the equilibrium between cell viability and apoptosis is related to the non-enzymatic antioxidant glutathione (GSH) in HEMA-exposed cells, the major mechanisms of adaptive antioxidant cell responses to maintain cellular redox homeostasis are still unknown. The present study provides insight into the induction of a communicating network of pathways under the control of the redox-sensitive transcription factor Nrf2, a major transcriptional activator of genes coding for enzymatic antioxidants. Here, oxidative stress was indicated by DCF fluorescence in cells after a short exposure (1 h) to HEMA, while DHR123 fluorescence significantly increased about 1.8-fold after a long exposure period (24 h) showing the formation of hydrogen peroxide (H2O2). The corresponding expression of Nrf2 was activated immediately after HEMA exposure (1 h) and remained constant up to 24 h. Nrf2-regulated expression of enzymes of the glutathione metabolism (glutathione peroxidase 1/2, glutathione reductase) decreased in HEMA-exposed cells as a result of GSH depletion, and superoxide dismutase expression was downregulated after H2O2 overproduction. However, the expression of Nrf2-controlled enzymatic antioxidants (catalase, peroxiredoxin, thioredoxin 1, thioredoxin reductase, heme oxygenase-1) and the NADPH-regenerating system (glucose 6-phosphate dehydrogenase, transaldolase) was increased. Phenolic tert-butylhydroquinone (tBHQ), a classic inducer of the Nrf2 pathway, reduced oxidative stress and protected cells from HEMA-induced cell death through a shift in the number of cells in necrosis to apoptosis. The

  8. 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.

  9. Second virial coefficient of poly(2-hydroxyethyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  10. MM and QM: conformational and vibrational spectra analysis of 2-hydroxyethyl acrylate.

    PubMed

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

    2015-02-25

    2-Hydroxyethyl acrylate is generally used with other acrylic and methacrylic products in order to get the desired characteristics of the final product. In this work we are about to make an assignment of experimental infrared bands with the help of a theoretical quantum chemistry calculations. The exact knowledge of some bands which are not characteristics of acrylic materials will enable us to make a quick analysis with available techniques of low costs for mixtures of polymers based on acrylate and methacrylate molecules. In the experimental part, the infrared spectrum of 2-hydroxyethyl acrylate is obtained by using a FTIR Perkin Elmer model 2000. In the computational part and as first step, the theoretical calculations are performed by the semi-empirical AM1 method for excluding similar structures of 2-hydroxyethyl acrylate molecule by a meticulous conformational analysis. As a second step the obtained structures are optimized using DFT. The simulated frequencies are then scaled and a tentative assignment is made based on band intensities and PED percentages. The theoretical calculations predict the existence of thirteen conformations two of them represent the majority of experimental bands in the infrared spectrum. Two neighbor experimental bands located at 1301 and 1207 cm(-1) maybe used as characteristic bands to locate and distinguish the existence of one or both conformations. PMID:25194321

  11. MM and QM: Conformational and vibrational spectra analysis of 2-hydroxyethyl acrylate

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    2-Hydroxyethyl acrylate is generally used with other acrylic and methacrylic products in order to get the desired characteristics of the final product. In this work we are about to make an assignment of experimental infrared bands with the help of a theoretical quantum chemistry calculations. The exact knowledge of some bands which are not characteristics of acrylic materials will enable us to make a quick analysis with available techniques of low costs for mixtures of polymers based on acrylate and methacrylate molecules. In the experimental part, the infrared spectrum of 2-hydroxyethyl acrylate is obtained by using a FTIR Perkin Elmer model 2000. In the computational part and as first step, the theoretical calculations are performed by the semi-empirical AM1 method for excluding similar structures of 2-hydroxyethyl acrylate molecule by a meticulous conformational analysis. As a second step the obtained structures are optimized using DFT. The simulated frequencies are then scaled and a tentative assignment is made based on band intensities and PED percentages. The theoretical calculations predict the existence of thirteen conformations two of them represent the majority of experimental bands in the infrared spectrum. Two neighbor experimental bands located at 1301 and 1207 cm-1 maybe used as characteristic bands to locate and distinguish the existence of one or both conformations.

  12. 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. PMID:26945182

  13. Protective effect of chitosan oligosaccharide lactate against DNA double-strand breaks induced by a model methacrylate dental adhesive

    PubMed Central

    Szczepanska, Joanna; Pawlowska, Elzbieta; Synowiec, Ewelina; Czarny, Piotr; Rekas, Marek; Blasiak, Janusz; Szaflik, Jacek Pawel

    2011-01-01

    Summary Background Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro. Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo. DSBs are the most serious type of DNA damage and if misrepaired or not repaired may lead to mutation, cancer transformation and cell death. Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative. Material/Methods We examined the protective action of chitosan oligosaccharide lactate (ChOL) against cytotoxic and genotoxic effects induced by monomers of the model adhesive consisting of 55% bisphenol A-diglycidyl dimethacrylate (Bis-GMA) and 45% 2-hydroxyethyl methacrylate (HEMA). We evaluated the extent of DSBs by the neutral comet assay and the phosphorylation of the H2AX histone test. Results ChOL increased the viability of HGFs exposed to Bis-GMA/HEMA as assessed by flow cytometry. ChOL decreased the extent of DSBs induced by Bis-GMA/HEMA as evaluated by neutral comet assay and phosphorylation of the H2AX histone. ChOL did not change mechanical properties of the model adhesive, as checked by the shear bond test. Scanning electron microscopy revealed a better sealing of the dentinal microtubules in the presence of ChOL, which may protect pulp cells against the harmful action of the monomers. Conclusions ChOL can be considered as an additive to methacrylate-based dental materials to prevent DSBs induction, but further studies are needed on its formulation with the methacrylates. PMID:21804456

  14. 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.

  15. Design of a new self-etching HEMA-free adhesive.

    PubMed

    Ikemura, Kunio; Ichizawa, Kensuke; Endo, Takeshi

    2009-09-01

    The effect of the pH value of single-bottle, self-etching 2-hydroxyethyl methacrylate (HEMA)-free adhesives on their shelf lives with bonding ability was investigated. Two experimental adhesives [SA-1 (pH=3.0); SA-2 (pH=2.1)] comprising 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA), 4-acryloyloxyethyltrimellitic acid (4-AET), Bis-GMA, water, and acetone, in which the pH values were controlled with 1N NaOH, were stored for 6 weeks at 50 degrees C in air. Shear bond strengths of aged adhesives to ground and unetched enamel and dentin were measured at a crosshead speed of 1.0 mm/min, and the data were analyzed by ANOVA. The resin-tooth bonding interfaces were further observed with SEM. With SA-1, the bond strengths to the tooth substrates were maintained throughout the 6 weeks. However, with SA-2, bond strength significantly degraded from weeks 4 to 6 (p<0.05). Based on SEM observation, non-aged and 6-week-aged adhesive SA-1 appeared to be strongly adhered to both enamel and dentin. It was found that the stability of the self-etching adhesive was influenced by its pH value. PMID:19822986

  16. 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. PMID:21477462

  17. Effect of monomeric sequence on mechanical properties of P(VP-co-HEMA) hydrogels at low hydration.

    PubMed

    Lee, Seung Geol; Brunello, Giuseppe F; Jang, Seung Soon; Lee, J Hannah; Bucknall, David G

    2009-05-14

    We have used molecular modeling of both random and blocky hydrogel networks of poly (N-vinyl-2-pyrrolidone-co-2-hydroxyethyl methacrylate) with VP:HEMA=37:13 composition to investigate the effect of the monomeric sequence on the mechanical properties. The degrees of monomer sequence randomness for the random and the blocky copolymers were 1.170 and 0.104, respectively, and the degree of polymerization was set as 50. The equilibrated density of the dry gel network was 0.968+/-0.007 and 0.911+/-0.007 g/cm3 for the random and the blocky sequences, respectively. In the partially hydrated state with 10 wt % water content, the effect of the monomeric sequence causes more distinct differences in density of 1.004+/-0.007 and 0.916+/-0.009 g/cm3 for the random and the blocky copolymer network, respectively. We observed that in such networks, the water molecules are associated more closely with the N-vinyl-2-pyrrolidone than with the hydroxyethyl methacrylate moieties, which is consistent with results from quantum mechanical solvation free energy calculations. By simulating a compressive deformation of the dry gels up to 80% strain, we found that the random sequence network develops higher stress levels than the blocky network. We also found that stress reduction occurs in the random sequence network due to the hydration, which is not evident in the blocky sequence network. This difference in stress reduction between the random and the blocky sequence networks is due to the difference in the structural rearrangement of monomers in the presence of water during deformation. The random sequence network is able to undergo much more efficient rearrangement of HEMA units than in the blocky sequence network. PMID:19358560

  18. 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

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1-dodecanethiol, N-(hydroxymethyl)-2-methyl-2-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated (generic). 721.10526 Section 721.10526...

  19. 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

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1-dodecanethiol, N-(hydroxymethyl)-2-methyl-2-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated (generic). 721.10526 Section 721.10526...

  20. Molecular dynamics simulation study of P (VP-co-HEMA) hydrogels: effect of water content on equilibrium structures and mechanical properties.

    PubMed

    Lee, Seung G; Brunello, Giuseppe F; Jang, Seung S; Bucknall, David G

    2009-10-01

    Poly (N-vinyl-2-pyrrolidone-co-2-hydroxyethyl methacrylate) (P(VP-co-HEMA)) hydrogel system with a composition of VP:HEMA=37:13 was studied using molecular dynamics simulations in order to investigate the effect of the water content on the equilibrium structures and the mechanical properties. The degree of randomness of the monomer sequence for the random and the blocky copolymers, were 1.170 and 0.104, respectively, and the degree of polymerization was fixed at 50. The equilibrated density of the hydrogel was found to be larger for the random sequence than for the blocky sequence at low water contents (<40 wt%), but this density difference decreased with increasing water content. The pair correlation function analysis shows that VP is more hydrophilic than HEMA and that the random sequence hydrogel is solvated more than the blocky sequence hydrogel at low water content, which disappears with increasing water content. Correspondingly, the water structure is more disrupted by the random sequence hydrogel at low water content but eventually develops the expected bulk water-like structure with increasing water content. From mechanical deformation simulations, stress-strain analysis showed that the VP is found to relax more efficiently, especially in the blocky sequence, so that the blocky sequence hydrogel shows less stress levels compared to the random sequence hydrogel. As the water content increases, the stress level becomes identical for both sequences. The elastic moduli of the hydrogels calculated from the constant strain energy minimization show the same trend with the stress-strain analysis. PMID:19656562

  1. 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. PMID:26700231

  2. 40 CFR 721.8130 - Propanamide, -(2-hydroxyethyl)-3-methoxy-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Specific Chemical Substances § 721.8130 Propanamide, -(2-hydroxyethyl)-3-methoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as propanamide...) (organic stripper additive). (ii) (b) Specific requirements. The provisions of subpart A of this part...

  3. 40 CFR 721.8130 - Propanamide, -(2-hydroxyethyl)-3-methoxy-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Specific Chemical Substances § 721.8130 Propanamide, -(2-hydroxyethyl)-3-methoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as propanamide...) (organic stripper additive). (ii) (b) Specific requirements. The provisions of subpart A of this part...

  4. 40 CFR 721.8130 - Propanamide, -(2-hydroxyethyl)-3-methoxy-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Specific Chemical Substances § 721.8130 Propanamide, -(2-hydroxyethyl)-3-methoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as propanamide...) (organic stripper additive). (ii) (b) Specific requirements. The provisions of subpart A of this part...

  5. 40 CFR 721.8130 - Propanamide, -(2-hydroxyethyl)-3-methoxy-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Specific Chemical Substances § 721.8130 Propanamide, -(2-hydroxyethyl)-3-methoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as propanamide...) (organic stripper additive). (ii) (b) Specific requirements. The provisions of subpart A of this part...

  6. 40 CFR 721.8130 - Propanamide, -(2-hydroxyethyl)-3-methoxy-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Specific Chemical Substances § 721.8130 Propanamide, -(2-hydroxyethyl)-3-methoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as propanamide...) (organic stripper additive). (ii) (b) Specific requirements. The provisions of subpart A of this part...

  7. Dynamic mechanical analysis and esterase degradation of dentin adhesives containing a branched methacrylate

    PubMed Central

    Park, Jong-Gu; Ye, Qiang; Topp, Elizabeth M.; Lee, Chi H.; Kostoryz, Elisabet L.; Misra, Anil; Spencer, Paulette

    2010-01-01

    A study of the dynamic mechanical properties and the enzymatic degradation of new dentin adhesives containing a multifunctional methacrylate are described. Adhesives contained 2-hydroxyethyl methacrylate (HEMA), 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]-propane (BisGMA), and a new multifunctional methacrylate with a branched side chain-trimethylolpropane mono allyl ether dimethacrylate (TMPEDMA). Adhesives were photopolymerized in the presence of 0, 8 and 16 wt% water to simulate wet bonding conditions in the mouth and compared to control adhesives. The degree of conversion as a function of irradiation time was comparable for experimental and control adhesives. In dynamic mechanical analysis (DMA), broad tan δ peaks were obtained for all samples, indicating that the polymerized networks are heterogeneous; comparison of the full-width-at-half-maximum values obtained from the tan δ curves indicated increased heterogeneity for samples cured in the presence of water and/or containing TMPEDMA. The experimental adhesive showed higher Tg and higher rubbery modulus indicating increased crosslink density as compared to the control. The improvement in esterase resistance afforded by adhesives containing the TMPEDMA is greater when this material is photopolymerized in the presence of water, suggesting better performance in the moist environment of the mouth. The improved esterase resistance of the new adhesive could be explained in terms of the densely crosslinked network structure and/or the steric hindrance of branched alkyl side chains. PMID:19358261

  8. 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

  9. Three-year clinical performance of a HEMA-free one-step self-etch adhesive in non-carious cervical lesions.

    PubMed

    Van Landuyt, Kirsten L; Peumans, Marleen; De Munck, Jan; Cardoso, Marcio V; Ermis, Banu; Van Meerbeek, Bart

    2011-12-01

    Despite the fact that one-step adhesives are currently used routinely in clinical practice, long-term studies on their clinical performance are scarce. The objective of this randomized controlled clinical trial was to test the hypothesis that a 2-hydroxyethyl methacrylate (HEMA)-free one-step self-etch adhesive performs worse than a conventional multistep etch-and-rinse adhesive. Two-hundred and seventy-six non-carious cervical lesions in 52 patients were restored with a micro-hybrid composite (Gradia Direct; GC). These restorations were bonded in random order either with the HEMA-free one-step adhesive G-Bond (GC) or with the 'gold-standard' (control) three-step adhesive Optibond FL (Kerr). The restorations were evaluated after 6, 12, 24, and 36 months of clinical service regarding retention, marginal adaptation, microleakage, caries occurrence, and sensitivity. After a medium-long period of 3 yr, similar success in clinical performance was observed for the simplified all-in-one adhesive and the conventional three-step adhesive. However, the one-step adhesive exhibited significantly more incisal marginal defects and discolorations. Whereas marginal degradation appeared to arrest for the multistep etch-and-rinse adhesive after 12 months, the enamel margins of the restorations bonded with the one-step self-etch adhesive continued to deteriorate. These incisal marginal defects were, however, small and could easily be removed by polishing. For both adhesives, large and sclerosed lesions appeared to be at higher risk of retention loss. PMID:22112039

  10. 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

  11. The influence of chemical structure on the properties in methacrylate-based dentin adhesives

    PubMed Central

    Park, Jonggu; Eslick, John; Ye, Qiang; Misra, Anil; Spencer, Paulette

    2011-01-01

    Objectives The objective of this study was to investigate the influence of the chemical structure of methacrylate monomers used in dentin adhesives on degree of conversion (DC), water sorption, and dynamic mechanical properties. Materials and methods Experimental adhesives containing 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]-propane (BisGMA), 2-hydroxyethyl methacrylate (HEMA), and co-monomer, 30/45/25 w/w were photo-polymerized. Ethyleneglycol dimethacrylate (EGDM), diethyleneglycol dimethacrylate (DEGDM), triethyleneglycol dimethacrylate (TEGDMA), 1,3-glycerol dimethacrylate (GDM), and glycerol trimethacrylate (GTM) were used as a co-monomer. The adhesives were characterized with regard to DC, water sorption, and dynamic mechanical analysis and compared to control adhesive [HEMA/BisGMA, 45/55 w/w]. Results DC and water sorption increased with an increase in the number of ethylene glycol units in the monomer. Experimental adhesive containing GDM showed significantly higher storage moduli (p < 0.05) in both dry and wet samples than experimental adhesives containing EGDM or DEGDM. The rubbery moduli of adhesives containing GDM and GTM were found to be significantly greater (p < 0.05) than that of the control. Adhesives containing GTM exhibited the widest tanδ curves, indicating the greatest structural heterogeneity. Significance The hydrophilicity, functionality and size of monomers in dentin adhesives affected the water sorption, solubility, crosslink density and heterogeneity of the polymer network. The experimental adhesives containing GDM and GTM showed higher rubbery moduli, indicating higher crosslink density accompanied by a decrease in the homogeneity of the polymer network structure. PMID:21816460

  12. Real-Time Polymerase Chain Reaction as a Tool for Evaluation of Magnetic Poly(Glycidyl methacrylate)-Based Microspheres in Molecular Diagnostics.

    PubMed

    Trachtová, Stepánka; Spanová, Alena; Horák, Daniel; Kozáková, Hana; Rittich, Bohuslav

    2016-01-01

    DNA amplification by real-time polymerase chain reaction (RT-PCR) was used for the evaluation of efficiency of polymer coating of magnetic hydrophilic poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (P(HEMA-co-GMA)) and poly(glycidyl methacrylate) (PGMA) microspheres with/without carboxyl groups. The inhibition effect of magnetic microspheres on real-time polymerase chain reaction (RT-PCR) course was evaluated by regression analysis after the addition of different concentrations of tested microspheres to PCR mixtures. Microspheres mostly did not interfere in RT-PCR till the concentration 50 µg/25 µl PCR mixture. No relationship between Fe content (and microsphere diameter) and inhibition effect was found. Microspheres containing carboxyl groups extinguished the fluorescence at lower concentrations (10-20 µg/25 µl PCR mixture) without inhibition of DNA amplification as PCR products were detected using agarose gel electrophoresis. Negative effect of maghemite on PCR course was partially reduced by coating of magnetic core by silica or polymers. Two inhibition mechanisms of DNA amplification were discussed in this work. PMID:26708828

  13. 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....

  14. 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....

  15. 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.

  16. 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).

  17. Permeability of protective gloves by HEMA and TEGDMA in the presence of solvents.

    PubMed

    Munksgaard, E C

    2000-04-01

    The breakthrough times and permeation rates of two commonly used allergenic components in dentin bonding agents or resins, HEMA and TEGDMA, were measured for 5 types of latex gloves and 5 types of nitrile gloves. In addition, the breakthrough times and permeation rates for the gloves were measured for HEMA and TEGDMA when diluted with either ethanol or acetone-solvents often appearing in dentin bonding agents. The mean breakthrough times for the 5 latex gloves for HEMA and TEGDMA, concentrated, diluted in ethanol, or diluted in acetone, were 4.9, 4.8, and 2.8 min, respectively. For the 5 nitrile gloves the equivalent breakthrough times were 15.7, 9.9, and 2.8 min, respectively. There were great variations between the various gloves, and 1 nitrile glove showed a breakthrough time of 28-30 min when tested with concentrated HEMA and TEGDMA. Compared to latex gloves, nitrile gloves have a longer-lasting protection against skin contamination with methacrylates in the absence of solvents. The longer protection was reduced or not present for methacrylates diluted in organic solvents, especially acetone. In addition, the nitrile gloves showed fairly high permeation rates in the presence of this solvent. The results indicate that latex and nitrile gloves only give a limited protection against allergenic methacrylates in dentin bonding agents when they contain acetone. PMID:10894426

  18. 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.

  19. 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

  20. Contact dermatitis caused by 2-HEMA and GM dentin primer solutions applied to guinea pigs and humans.

    PubMed

    Katsuno, K; Manabe, A; Itoh, K; Nakamura, Y; Wakumoto, S; Hisamitsu, H; Yoshida, T

    1996-06-01

    The purposes of this study were to examine whether 2-HEMA, GM, and methacrylic acid cause contact dermatitis, and to determine the optimum concentrations of these primers for sensitization and challenge in guinea pigs. A sensitizing concentration of 0.2% 2-HEMA resulted in strong rubefaction and several vesiculopapules in response to the challenge, and a sensitizing concentration of 0.5% GM produced strong rubefaction at 24 hours. We also observed the development of contact dermatitis on human brachia in a closed-patch test. Skin that was treated with both 2-HEMA and GM clearly showed the onset of rubefaction and itchiness. 2-HEMA caused sensitized delayed allergic reactions at all the concentrations tested. PMID:8940535

  1. COMPARISON OF SUBCHRONIC NEUROTOXICITY OF 2-HYDROXYETHYL ACRYLATE AND ACRYLAMIDE IN RATS

    EPA Science Inventory

    The comparative neurotoxicity of subchronic exposure to 2 hydroxyethyl acrylate (HEA) and acrylamide (ACR) was evaluated using a functional observational battery (FOB) and neurohistology. hree dose levels of each compound (HEA: 3, 20, 60 mg/kg; ACR: I, 4, 12 mg/kg) were administe...

  2. Effect of coinitiator and water on the photoreactivity and photopolymerization of HEMA/camphoquinone-based reactant mixtures

    PubMed Central

    Wang, Yong; Spencer, Paulette; Yao, Xiaomei; Ye, Qiang

    2007-01-01

    It was reported previously that, in the presence of water, a commercially available light-activated BisGMA/HEMA adhesive underwent physical separation into solid BisGMA-rich particles and a fluid-like HEMA-rich phase. The HEMA-rich phase exhibited limited monomer conversion suggesting that the photoinitiator is localized to the hydrophobic phase or that the photoinitiator is not compatible with the hydrophilic HEMA. The objective of the present study was to identify photoinitiators that are compatible with the hydrophilic HEMA-rich phase, when the mixtures are prepared without and with water added. The photoinitiator was camphoquinone (CQ, 0.5 mol %), and the coinitiators (0.5 mol %) were 2,2′-dihydroxyethyl-para-toluidine (DHEPT), dimethylaminoethyl methacrylate (DMAEMA), and N-phenylgly-cine (NPG), and (1 wt %) diphenyliodonium chloride (DPIC). Reactivities were evaluated using photodifferential scanning calorimetry, at 37°C, using visible light (>418 nm), with the parameters determined being enthalpy (ΔH), the induction time (herein defined as the time for 1% of the photopolymerization to be complete), and the time at which the maximum exotherm occurred. The degree of monomer conversion was measured using micro-Raman spectroscopy. It was shown that the reactivity ranking (based on time to exotherm peak maximum and total enthalpy) was HEMA/CQ/DHEPT < HEMA/CQ/DMAEMA < HEMA/CQ/NPG. Reactivity was dramatically increased for CQ/DMAEMA and CQ/NPG in the presence of DPIC, but not for CQ/DHEPT. Water has a major effect on HEMA conversion. At 10% of water, the conversion level of HEMA formulated with CQ/DMEMA dropped from ~100% to 86%. In comparison, the conversion in 10% of water increased to nearly 96% when DPIC was used. The results suggest that DHEPT, which is commonly used in commercial adhesives, is not compatible with HEMA. Both NPG and DMAEMA appear compatible with the HEMA. The ionic hydrophilic iodonium salt, DPIC, enhances the polymerization of HEMA, even

  3. 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

  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, 2011 CFR

    2011-07-01

    ...-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, 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...

  6. Thermal analysis of water in p(HEMA) hydrogels.

    PubMed

    Roorda, W E; Bouwstra, J A; de Vries, M A; Junginger, H E

    1988-11-01

    Hydrogels composed of poly(hydroxyethyl methacrylate) (pHEMA) and water were investigated using differential thermal analysis (DTA) and adiabatic calorimetry (AC). The results show that the crystallization of water in the gels is a very gradual process, leading to the development of a metastable, non-equilibrium state. They are not in agreement with models that assume the actual presence of thermodynamically different classes of water in the gels, based on the abnormal melting behaviour of this water. The results indicate that the internal structure of these gels can be described as that of an elastic solution, in which the water molecules are distributed continuously over all possible orientations to and interactions with the polymer. PMID:3224136

  7. 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.

  8. 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...

  9. 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...

  10. 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-hydroxyethyl)-, bromide (1:1). 721.10115 Section 721.10115 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  11. 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...

  12. 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...

  13. 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... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10136 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with...

  14. 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... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10136 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with...

  15. 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... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10136 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with...

  16. 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... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10136 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with...

  17. 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... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10136 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with...

  18. 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.

  19. 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.

  20. New 4-hydroxy-N-(2-hydroxyethyl)butanamides: Structure and acidity

    NASA Astrophysics Data System (ADS)

    Duarte-Hernández, Angélica M.; Contreras, Rosalinda; Suárez-Moreno, Galdina V.; González, Felipe J.; Flores-Parra, Angelina

    2015-02-01

    Optically active new 4-hydroxy-N-(2-hydroxyethyl)butanamides are reported. The structure in the solid state of four racemic mixtures and three enantiomeric pure compounds was determined by X-ray diffraction. The solid state arrangements of enantiomerically pure compounds were compared with those of their racemic mixtures. The butanamides prefer lineal conformations in the solid state. They form dimers and polymers through intermolecular hydrogen bonds. Variable temperature 1H NMR experiments were performed in order to analyse the strength of the hydrogen bonds in the neutral molecules in solution. The pKa values of the dihydroxybutanamides in DMSO determined by cyclic voltammetric (11.1-14.5) were lower than those reported for amides RNHCOR without hydroxyl groups (25.9). The latter motivated us to investigate the role of hydrogen bonds in the stabilization of the corresponding anions and in consequence in the acidity of the amides. The explanation of the enhanced Nsbnd H acidity of dihydroxybutanamides was found in the cyclic voltammetric experiments, in conductimetric titrations using nBu4NOH in methanol and titration with CsOH in acetonitrile. The optimised structures for the neutral molecules and their mono and dianions calculated by ab-initio HF(6-31 + G∗) and B3LYP(6-31 + G∗) methods supported the explanation of the enhanced Nsbnd H acidity.

  1. Sonocatalytic degradation of 2-hydroxyethyl cellulose in the presence of some nanoparticles.

    PubMed

    Taghizadeh, Mohammad Taghi; Seifi-Aghjekohal, Parinaz

    2015-09-01

    The degradation of 2-hydroxyethyl cellulose (HEC) by means of ultrasound irradiation and its combination with heterogeneous catalysts such as TiO2 (Rutile and Anatase), Montmorillonite Clay (MMT), ZnO and Fe3O4 nanoparticles was investigated. The effect of the type and quantity of nanoparticles, the initial molecular weight of polymer and the different ultrasonic power have been studied. Degradation behavior of HEC was studied through FTIR, XRD and SEM techniques and kinetics of degradation was studied by viscometry. Also, reduce in molecular weight (Mw) of polymer was investigated by gel permeation chromatography (GPC) analysis. The results of experiments suggested that the sonocatalytic degradation of HEC were remarkably higher than sonolytic degradation. However, the catalytic activity of nanoparticles in contrast to the ultrasonic irradiation was different. The experimental results revealed that the best HEC degradation can be obtained when the added Fe3O4 amount was 0.4 g/L. Furthermore, kinetic analysis of the polymer degradation process was carried out in this study. PMID:25637291

  2. Synthesis, and Surface-Active Properties of Palm Fatty Acid and 1(2-HYDROXYETHYL - Esteramide Quat

    NASA Astrophysics Data System (ADS)

    Mishra, Shilpi; Tyagi, V. K.

    In this study, an attempt has been made to synthesize esteramide quat by esterification of palm fatty acids with 1(2-hydroxyethyl piperazine) followed by quaternization with dimethyl sulphate (DMS). The optimum reaction conditions for esterification of palm fatty acids and 1(2-hydroxyethyl piperazine) were found to be 170°C reaction temperature and 150 mmHg pressure. The obtained esteramide was subjected to quaternization with different molar ratios of DMS. The consequences revealed that esteramide to DMS ratio of 1 : 0.95 and duration of quaternization for 2 h yielded esteramide quat of maximum cationic content, i.e., 64.9%. The instrumental analysis, viz. FT-IR, 1H NMR, 13C NMR verified the esterification and subsequent quaternization of the obtained esteramide quat. Furthermore, the surface-active and performance properties of synthesized esteramide quat were also evaluated.

  3. INFLUENCE OF HEMA CONTENT ON THE MECHANICAL AND BONDING PROPERTIES OF EXPERIMENTAL HEMA-ADDED GLASS IONOMER CEMENTS

    PubMed Central

    Lim, Ho-Nam; Kim, Seong-Hwan; Yu, Bin; Lee, Yong-Keun

    2009-01-01

    The purpose of this study was to determine the influence of incrementally added uncured HEMA in experimental HEMA-added glass ionomer cement (HAGICs) on the mechanical and shear bond strength (SBS) of these materials. Increasing contents of uncured HEMA (10-50 wt.%) were added to a commercial glass ionomer cement liquid (Fuji II, GC, Japan), and the compressive and diametral tensile strengths of the resulting HAGICs were measured. The SBS to non-precious alloy, precious alloy, enamel and dentin was also determined after these surfaces were subjected to either airborne-particle abrasion (Aa) or SiC abrasive paper grinding (Sp). Both strength properties of the HAGICs first increased and then decreased as the HEMA content increased, with a maximum value obtained when the HEMA content was 20% for the compressive strength and 40% for the tensile strength. The SBS was influenced by the HEMA content, the surface treatment, and the type of bonding surface (p<0.05). These results suggest that addition of an appropriate amount of HEMA to glass ionomer cement would increase diametral tensile strength as well as bond strength to alloys and teeth. These results also confirm that the optimal HEMA content ranged from 20 to 40% within the limitations of this experimental condition. PMID:19668995

  4. 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

  5. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    Methyl methacrylate ; CASRN 80 - 62 - 6 ( 03 / 02 / 98 ) 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 f

  6. Designing PolyHEMA Substrates that Mimic the Viscoelastic Response of Soft Tissue

    PubMed Central

    Holt, Brian; Tripathi, Anubhav; Morgan, Jeffrey R.

    2011-01-01

    Matching the mechanical properties of a biomaterial to soft tissue is often overlooked despite the fact that it’s well known that cells respond to and are capable of changing their mechanical environment. In this paper, we used NaCl and alginate beads as porogens to make a series of micro- and macro-porous pHEMA substrates [poly(2-hydroxyethly methacrylate)] and quantified their mechanical behavior under low-magnitude shear loads over physiologically relevant frequencies. Using a stress-controlled rheometer, we performed isothermal (37°C) frequency response experiments between 0.628 and 75.4 rad/s [0.01–12Hz] at 0.1% strain. Both micro- and macro-porous pHEMA substrates were predominately elastic in nature with a narrow range of G′ and G″ values that mimicked the response of human skin. The magnitude of the G′ and G″ values of the macro-porous substrates were designed to closely match human skin. To determine how cell growth might alter their mechanical properties, pHEMA substrates were functionalized and human skin fibroblasts grown on them for fourteen days. As a result of cell growth, the magnitude of G′ and G″ increased at low frequencies while also altering the degree of high frequency dependence, indicating that cellular interactions with the micro-pore infrastructure has a profound effect on the viscoelastic behavior of the substrates. These data could be fit to a mathematical model describing a soft solid. A quantitative understanding of the mechanical behavior of biomaterials in regimes that are physiologically relevant and how these mechanics may change after implantation may aid in the design of new materials. PMID:21496821

  7. In-situ sol-gel synthesis and characterization of bioactive pHEMA/SiO2 blend hybrids.

    PubMed

    Silvestri, B; Luciani, G; Costantini, A; Tescione, F; Branda, F; Pezzella, A

    2009-05-01

    A novel procedure to synthesize poly(2-hydroxyethylmethacrylate)-silica blend hybrids is presented. Methacrylate monomers bearing an alkoxysilyl unit, prepared by Michael addition of 2-hydroxyethylmethacrylate (HEMA) to 3-Aminopropyltriethoxysilane (APTS) were employed. By (13)C NMR and mass analysis it was possible to establish the formation of coupling hybrid species. Hybrid materials, with final concentration ranging from 10% to 30% w/w of silica gel to the mass of polymer, were obtained through basic catalyzed sol-gel process of tetraethoxysilane (TEOS) and the alkoxysilyl unit of the hybrid monomer, followed by in-situ free-radical polymerization. The hybrids were characterized as far as concerns their thermal properties (glass transition temperature, decomposition temperature), their sorption behavior in water, and in-vitro bioactivity. Optical transparency, higher glass transition temperature, and higher decomposition temperature than pHEMA suggest an increase in either density or intensity of cross-links between the organic and the inorganic phases. The swelling ratio of the 30% hybrids is comparable to pHEMA, whereas it is lower for the other compositions. In-vitro bioactivity of the hybrids, due to the inorganic phase, was ascertained. Soaking time required for apatite deposition on the samples surface decreases as the content of silica gel increases. Therefore, the obtained bioactive hybrids can be used to make bioactive scaffolds for bone engineering. PMID:18823022

  8. 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.

  9. Microlens fabrication on tot’hema sensitized gelatin

    NASA Astrophysics Data System (ADS)

    Murić, Branka; Pantelić, Dejan; Vasiljević, Darko; Panić, Bratimir

    2008-03-01

    Photosensitivity of tot'hema and eosin sensitized gelatin layer (TESG) is analyzed. Tot'hema is a trade name of a drinkable solution used in medicine for treatment of anemia, while eosin is an organic dye, used in medicine too. The resulting material is cheap, easy to use, nonpoisoneous and photosensitive in the green part of spectrum. Microlenses, arrays of microlenses and sinusoidal transmission diffraction gratings were recorded using Nd:YAG laser operating at 532 nm.

  10. Enhanced reproducibility of the human gel-based tear proteome maps in the presence of di-(2-hydroxyethyl) disulfide.

    PubMed

    Saraygord-Afshari, Neda; Naderi-Manesh, Hossein; Naderi, Mostafa

    2014-01-01

    Patterns obtained in two-dimensional gel electrophoresis (2-DE) in the previously published articles suggest a varying number of proteins. To seek the cause of this variation, we investigated the effect of reduction power on the overall tear proteome maps. To this end, the buffers of two reducing agents, dithiothreitol (DTT) at nine different concentrations and di-(2-hydroxyethyl) disulfide (HED), were examined. The assay showed that HED clearly improved 2-DE resolution, increased the number of detectable protein spots, and offered well-resolved chain regions in comparison with those treated with DTT. Furthermore, this study introduced increasing the reduction power as a remedy to increase the reproducibility of two-dimensional human tear proteome maps. In addition, the results of our assessment showed that improved reduction efficiency was accompanied by increased procedure reproducibility from 42% to 89%. PMID:24575874

  11. PolyGuanine methacrylate cryogels for ribonucleic acid purification.

    PubMed

    Köse, Kazım; Uzun, Lokman

    2016-05-01

    The isolation and purification of ribonucleic acid have attracted attention recently for the understanding of the functions in detail because of the necessity for the treatment of genetic diseases. In this study, guanine-incorporated polymeric cryogels were developed to obtain highly purified ribonucleic acid. The satisfactory purification performance was achieved with the guanine-incorporated poly (2-hydroxyethyl methacrylate-guanine methacrylate) cryogels. The most crucial advantages to use guanine as a functional monomer are to obtain a real natural interaction between guanine on the polymeric material and cytosine on the ribonucleic acid. Moreover, using cryogel with a highly porous structure and high swelling ratio provide advantages of getting more water within the structure to get more analyte to interact. The characterization of cryogels has proved the success of the synthesis and the perfect natural interaction to be taken place between the ligand (guanine methacrylate) and the cytosine in the ribonucleic acid molecules. Although the pores within the structure of cryogels are small, they provide efficient and fast adsorption. The chromatographic separation performance was investigated for different conditions (pH, temperature etc.). The desorption ratio and reusability were also analyzed at the end of the five adsorption-desorption cycles with no significant changes. PMID:27004613

  12. 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. PMID:17386536

  13. 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.

  14. Effect of photografting 2-hydroxyethyl acrylate on the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) fibroporous mats.

    PubMed

    Mayuri, P V; Bhatt, Anugya; Joseph, Roy; Ramesh, P

    2016-03-01

    Poly(ethylene-co-vinyl alcohol) (EVAL) has been recommended as a material suitable for blood contacting applications. Effect of ethylene content and associated hydrophobicity of EVAL on the blood-material interactions have been documented in the literature. In this work, surface chemistry of EVAL substrate was altered by photografting a hydrophilic monomer, 2-hydroxyethyl acrylate (HEA) with the aid of a photoinitiator, benzophenone (BP), and the effect of surface modification on the blood-material interactions was investigated. Since the modified material was intended to be used as leukodepletion filters, a solution containing EVAL, HEA and BP was electrospun into fibroporous mats and UV treated to induce grafting. Degree of grafting, bonding between fibers and fiber diameter increased with increase in UV exposure time whereas mechanical properties showed a decreasing trend. Decreased water contact angle indicated improved wetting characteristics. In vitro hemocompatibility tests revealed that the modified EVAL surface exhibited significantly lower hemolytic activity, protein adsorption and platelet adhesion than neat EVAL. The modification did not have any substantial effect on the activation of the complement system and coagulation parameters. Photografting led to significant reduction in the adhesion of red blood cells (RBC) whereas white blood cell (WBC) consumption remained above 90%. The results implied that photografting HEA on EVAL substantially improves hemocompatibility of EVAL and when it is used as a filter, it selectively removes leukocytes and allows easy passage of other blood components. PMID:26706502

  15. Effects of Dental Methacrylates on Oxygen Consumption and Redox Status of Human Pulp Cells

    PubMed Central

    Nocca, Giuseppina; Callà, Cinzia; Martorana, Giuseppe Ettore; Cicillini, Loredana; Lupi, Alessandro; Cordaro, Massimo; Luisa Gozzo, Maria

    2014-01-01

    Several studies have already demonstrated that the incomplete polymerization of resin-based dental materials causes the release of monomers which might affect cell metabolism. The aim of this study was to investigate the effects of triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, urethane dimethacrylate, and 2-hydroxyethyl methacrylate on (1) cellular energy metabolism, evaluating oxygen consumption rate, glucose consumption, glucose 6-phosphate dehydrogenase activity, and lactate production, and (2) cellular redox status, through the evaluation of glutathione concentration and of the activities of enzymes regulating glutathione metabolism. Methods. Human pulp cells were used and oxygen consumption was measured by means of a Clark electrode. Moreover, reactive oxygen species production was quantified. Enzymatic activity and glucose and lactate concentrations were determined through a specific kit. Results. Triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, and 2-hydroxyethyl methacrylate induced a decrease in oxygen consumption rate, an enhancement of glucose consumption, and lactate production, whilst glucose 6-phosphate dehydrogenase and glutathione reductase activity were not significantly modified. Moreover, the monomers induced an increase of reactive oxygen species production with a consequent increase of superoxide dismutase and catalase enzymatic activities. A depletion of both reduced and total glutathione was also observed. Conclusion. The obtained results indicate that dental monomers might alter energy metabolism and glutathione redox balance in human pulp cells. PMID:24693541

  16. Variable temperature 1H and 13C NMR study of restricted rotation in N,N-bis(2-hydroxyethyl)acetamide

    NASA Astrophysics Data System (ADS)

    Aitken, R. Alan; Smith, Melanja H.; Wilson, Heather S.

    2016-06-01

    N,N-bis(2-hydroxyethyl)acetamide shows restricted rotation about the amide bond in both 1H and 13C NMR spectra rendering the two hydroxyethyl groups non-equivalent. A variable temperature study in CD3SOCD3 allowed estimation of the free energy barrier to rotation as 75.6 ± 0.2 kJ mol-1. Previously published data in CDCl3 appears to be erroneous.

  17. 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. PMID:23613115

  18. 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

  19. Dispersion of luminescent nanoparticles in different derivatives of poly(ethyl methacrylate).

    PubMed

    Davion, B; Delhorbe, V; Péralta, S P; Goubard, F; Vidal, F

    2011-04-01

    Gd2O3:Tb(5%) nanoparticles were prepared via the polyol route and dispersed without any stabilizer in several ethyl methacrylate derivatives matrices such as poly(ethyl methacrylate), poly(2-methoxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate) (PHEMA). Nanocomposites were obtained via free-radical polymerization of methacrylic monomers with ethylene glycol dimethacrylate as crosslinker and colloidal solution of Gd2O3:Tb(5%) nanoparticles. Best results are obtained with PHEMA in which the dispersed Gd2O3:Tb(5%) nanoparticles are spherical with a mean diameter of 15 nm, as measured by TEM. The obtained solid Gd2O3:Tb(5%)/PHEMA nanocomposites are highly transparent (in the visible spectral range) and exhibit characteristic photoluminescence of Tb3+ 5D4-7F(J) (J = 6-3), with 5D4-7F5 strong green emission at 536 nm upon UV excitation. The nanoparticles and nanocomposites have been well characterized by high-resolution transmission electron microscope (TEM), UV/Vis transmission spectra, photoluminescence excitation, and emission spectra. PMID:21776688

  20. 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.

  1. Lipophilic and hydrophilic esters of 4-acetyl-2-(2-hydroxyethyl)-5,6-bis(4-chlorophenyl)-2H-pyridazin-3-one as antihypertensive agents.

    PubMed

    Fogt, S W; Scozzie, J A; Heilman, R D; Powers, L J

    1980-12-01

    In an attempt to enhance the antihypertensive activity of 4-acetyl-2-(2-hydroxyethyl)-5,6-bis(4-chlorophenyl)-2H-pyridazin-3-one, 1, a series of lipophilic and hydrophilic esters was synthesized. These derivatives possessed increased lipid and aqueous solubility, respectively. The esters, in general, cause a larger blood-pressure drop than 1 when tested at high doses in the spontaneously hypertensive rat (SHR) model. At lower doses the antihypertensive activity is the same as with 1. PMID:7452699

  2. 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. PMID:26785924

  3. Effects of water content and initiator composition on photopolymerization of a model BisGMA/HEMA resin

    PubMed Central

    Guo, Xinglin; Wang, Yong; Spencer, Paulette; Ye, Qiang; Yao, Xiaomei

    2008-01-01

    Aims The purpose of this study was to evaluate the effects of photoinitiator type and water content on the polymerization rate (Rp) and degree of conversion (DC) of a model BisGMA/HEMA-based resin. Materials and methods The comonomer mixture consisted of BisGMA/HEMA (60/40 by weight). Different two- or three-component photoinitiator systems were incorporated. Two-component systems were 0.5% CQ (camphorquinone) and 0.5% DMAEMA (2-(dimethylamino) ethyl methacrylate) or 0.5% CQ and 0.5% 4E (Ethyl 4-dimethylaminobenzoate). The three-component systems were added 1% DPIHP (diphenyliodonium hexafluorophosphate) to the above systems. Each system was tested as made, or after addition of 5, 10, 15wt% water. When cured under a conventional dental light, the Rp and DC of each formulation was determined using time-resolved attenuated total reflection (ATR)-Fourier transform infrared (FTIR) spectroscopy. Results For mixtures containing two-component initiator systems, when the hydrophobic initiator CQ was used in combination with hydrophilic DMAEMA, Rps and DCs were dramatically decreased as a function of water content. The Rps and DCs of the hydrophobic CQ/4E system were higher than those of the CQ/DMAEMA system in the presence of water. For three-component initiator systems, incorporation of DPIHP enhanced the polymerization of all mixtures in the presence of water compared to their counterpart two-component initiators. Interestingly, the CQ/DMAEMA caused greater DC and Rp when DPIHP was used. Significance The hydrophobicity/hydrophilicity of photoinitiator components significantly affects both the DC as well as Rp when in the presence of water. The results indicate that formulation of photoinitiator components should be based on the effectiveness of the bonding systems under both dry and wet conditions. PMID:18045679

  4. 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. PMID:27455744

  5. Synthesis and characterization of N, N'-bis[2-hydroxyethyl]-1,4,6,8-naphthalenediimide with para substituted of phenols based on charge-transfer complexes

    NASA Astrophysics Data System (ADS)

    Refat, Moamen S.; Killa, Hamada M. A.; Grabchev, Ivo; El-Sayed, Mohamed Y.

    2007-09-01

    The interaction of charge-transfer (CT) complexes resulted from the reaction of N, N'-bis[2-hydroxyethyl]-1,4,6,8-naphthalenediimide (BHENDI) with some various acceptors like as substituted phenols in para position; 4-aminophenol (4AP), 4-methylphenol (4MP) and 4-nitrophenol (4NP) have been studied in methanol at room temperature. The reaction was studied using electronic (UV-vis), mid infrared, and 1H NMR spectra and thermal measurements (TGA and DTG) as well as elemental analysis CHN. The chemical analysis data of the resulted CT-complexes, BHENDI-acceptors, reveal that the formation of a 1:2 CT complexes in all cases. The interaction of N, N'-bis[2-hydroxyethyl]-1,4,6,8-naphthalenediimide and phenolic acceptors were investigated spectrophotometrically and found two detected CT bands have n-π * transition. The donor site involved in CT interaction is the diimide two nitrogen atoms by forming hydrogen bonding. The kinetic thermodynamic parameters like Δ E, Δ H, Δ S and Δ G are calculated from the DTG diagrams using Coats-Redfern method. The electrical conductivity properties for the solid CT complexes were measured within the temperature of room 25 °C.

  6. Synthesis and evaluation of novel siloxane-methacrylate monomers used as dentin adhesives

    PubMed Central

    Ge, Xueping; Ye, Qiang; Song, Linyong; Misra, Anil; Spencer, Paulette

    2014-01-01

    Objectives The objectives of this study were to synthesize two new siloxane-methacrylate (SM) monomers for application in dentin adhesives and to investigate the influence of different functionality of the siloxane-containing monomers on the adhesive photopolymerization, water sorption, and mechanical properties. Materials and method Two siloxane-methacrylate monomers (SM1 and SM2) with four and eight methacrylate groups were synthesized. Dentin adhesives containing BisGMA, HEMA and the siloxane-methacrylate monomers were photo-polymerized. The experimental adhesives were compared with the control adhesive (HEMA/BisGMA 45/55 w/w) and characterized with regard to degree of conversion (DC), water miscibility of the liquid resin, water sorption and dynamic mechanical analysis (DMA). Results The experimental adhesives exhibited improved water miscibility as compared to the control. When cured in the presence of 12 wt % water to simulate the wet environment of the mouth, the SM-containing adhesives showed DC comparable to the control. The experimental adhesives showed higher rubbery modulus than the control under dry conditions. Under wet conditions, the mechanical properties of the formulations containing SM monomer with increased functionality were comparable with the control, even with more water sorption. Significance The concentration and functionality of the newly synthesized siloxane-methacrylate monomers affected the water miscibility, water sorption and mechanical properties of the adhesives. The experimental adhesives show improved water compatibility compared with the control. The mechanical properties were enhanced with an increase of the functionality of the siloxane-containing monomers. The results provide critical structure/property relationships and important information for future development of durable, versatile siloxane-containing dentin adhesives. PMID:24993811

  7. Chemical modification of glass surface with a monolayer of nonchromophoric and chromophoric methacrylate terpolymer

    NASA Astrophysics Data System (ADS)

    Janik, Ryszard; Kucharski, Stanisław; Sobolewska, Anna; Barille, Regis

    2010-11-01

    The methacrylate terpolymers, a nonchromophoric and chromophoric one, containing 2-hydroxyethyl groups were reacted with 3-isocyanatopropyltriethoxysilane to obtain reactive polymers able to form covalent bonding with -SiOH groups of the glass surface via triethoxysilane group condensation. Chemical modification of the Corning 2949 glass plates treated in this way resulted in increase of wetting angle from 11° to ca. 70-73°. Determination of ellipsometric parameters revealed low value of the substrate refractive index as compared with that of bulk Corning 2949 glass suggesting roughness of the surface. The AFM image of the bare glass surface and that modified with terpolymer monolayer confirmed this phenomenon. Modification of the glass with the terpolymer monolayer made it possible to create the substrate surface well suited for deposition of familiar chromophore film by spin-coating. The chromophore polymer film deposited onto the modified glass surface was found to be resistant to come unstuck in aqueous solution.

  8. 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.

  9. Synthesis of 2-(2-hydroxyethyl)-1-(2-hydroxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline and pseudosymmetry in its crystal structure.

    PubMed

    Turgunov, Kambarali K; Zhurakulov, Sherzod N; Englert, Ulli; Vinogradova, Valentina I; Tashkhodjaev, Bakhodir

    2016-08-01

    Natural and synthetic isoquinoline alkaloids display a wide variety of potent biological activities. The title 1-aryl-2-hydroxyethyl-1,2,3,4-tetrahydroisoquinoline, C19H23NO4, crystallizes with two molecules in the asymmetric unit related by pseudo-translation but differing only slightly in conformation. The pseudosymmetry is also reflected in the diffraction pattern. The subset of reflections corresponding to the smaller cell and average structure are on average twice as intense as those subtending the larger cell. Tentative refinement in the subcell leads to a disordered structural model with satisfactory agreement factors and, after appropriate use of restraints, acceptable molecular geometry but significantly larger and more anisotropic displacement parameters. In the correct unit cell, the independent molecules differ with respect to the orientation of the hydroxyethyl group. Intramolecular hydrogen bonding occurs between the hydroxyphenyl group and the N atom. PMID:27487334

  10. Synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: microbial viabilities at different ionic liquids concentrations.

    PubMed

    Hossain, M Ismail; El-Harbawi, Mohanad; Alitheen, Noorjahan Banu Mohamed; Noaman, Yousr Abdulhadi; Lévêque, Jean-Marc; Yin, Chun-Yang

    2013-01-01

    Three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ILs) [2OHimC(n)][Cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by IR and NMR spectroscopies and elemental analysis. Their anti-microbial activities were investigated using the well-diffusion method. The viabilities of Escherichia coli, Aeromonas hydrophila, Listeria monocytogenes and Salmonella enterica as a function of IL concentrations were studied. The minimal inhibitory concentrations (MICs) and EC₅₀ values for the present ILs were within the concentration range from 60 to 125 mM and 23 to 73 mM. The anti-microbial potencies of the present ILs were compared to a standard antibiotic, gentamicin. The finding affords additional perspective on the level of ILs toxicity to aquatic lifeforms and yet, this characteristic can be readily harnessed to detect microbial growth and activity. PMID:23107478

  11. 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.

  12. Synthesis, Characterization, and In Vitro Evaluation of New Ibuprofen Polymeric Prodrugs Based on 2-Hydroxypropyl Methacrylate

    PubMed Central

    Babazadeh, Mirzaagha; Sheidaei, Maryam; Abbaspour, Sara; Edjlali, Ladan

    2013-01-01

    The present research work describes the synthesis and evaluation of new acrylic-type polymeric systems having degradable ester bonds linked to ibuprofen as materials for drug delivery. Ibuprofen was linked to 2-hydroxy-propyl methacrylate by an activated ester methodology in a one-pot procedure with a high yield. The resulting material was copolymerized with either 2-hydroxyethyl methacrylate or methyl methacrylate (in 1:3 mole ratios) by the free radical polymerization method, utilizing azoisobutyronitrile at 65–70 °C. The characterization of the resulting products by FTIR, 1H NMR, 13C NMR, DSC, and elemental analysis confirmed their synthesis successfully. Ibuprofen release from the obtained polymers was preliminarily evaluated at different buffered solutions (pH 1, 7.4, and 10) into dialysis bags to show the capacity of prodrugs to release the drug under hydrolytic conditions. Detection of hydrolysis by UV spectroscopy at selected intervals showed that the drug can be released by selective hydrolysis of the ester bond at the side of the drug moiety. The release profiles indicated that the hydrolytic behavior of polymers is strongly based on the polymer hydrophilicity and the pH value of the hydrolysis solution. The results suggest that these polymers could be useful in controlled release systems. PMID:23641345

  13. 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

  14. 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.

  15. Evaluation of skin irritation and sensitization of two diol solutions used as experimental dentin primers in humans and guinea pigs.

    PubMed

    Kurihara, A; Manabe, A; Katsuno, K; Itoh, K; Hisamitsu, H; Wakumoto, S; Yoshida, T

    1996-12-01

    The purpose of the present study was to evaluate the safety of ethylene glyco (EG) and 1,6-hexanediol (HD) solutions as experimental dentin primers when subjected to the guinea pig maximization test (GPMT), primary irritation test, cumulative skin irritation test and human patch test. No primary and cumulative skin irritation resulting from the use of 62.5% EG or 45% HD solutions was observed. In the case of GPMT, the animals sensitized with 2-hydroxyethyl methacrylate (2-HEMA) responded to 100% HD. 62.5% EG and 45% HD as dentin primers were safer than 2-HEMA such as a methacrylic primer. PMID:9550022

  16. 76 FR 69659 - Methacrylic Acid-Methyl Methacrylate-Polyethylene Glycol Monomethyl Ether Methacrylate Graft...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-09

    ...This regulation establishes an exemption from the requirement of a tolerance for residues of methacrylic acid-methyl methacrylate- polyethylene glycol monomethyl ether methacrylate graft copolymer when used as an inert ingredient in a pesticide chemical formulation. Akzo Noel Surface Chemistry LLC submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an......

  17. Effects of Grafting Density and Film Thickness on the Adhesion of Staphylococcus epidermidis to Poly(2-hydroxy ethyl methacrylate) and Poly(poly(ethylene glycol)methacrylate) Brushes.

    PubMed

    Ibanescu, Sorin-Alexandru; Nowakowska, Justyna; Khanna, Nina; Landmann, Regine; Klok, Harm-Anton

    2016-05-01

    Thin polymer films that prevent the adhesion of bacteria are of interest as coatings for the development of infection-resistant biomaterials. This study investigates the influence of grafting density and film thickness on the adhesion of Staphylococcus epidermidis to poly(poly(ethylene glycol)methacrylate) (PPEGMA) and poly(2-hydroxyethyl methacrylate) (PHEMA) brushes prepared via surface-initiated atom transfer radical polymerization (SI-ATRP). These brushes are compared with poly(ethylene glycol) (PEG) brushes, which are obtained by grafting PEG onto an epoxide-modified substrate. Except for very low grafting densities (ρ = 1%), crystal violet staining experiments show that the PHEMA and PPEGMA brushes are equally effective as the PEG-modified surfaces in preventing S. epidermis adhesion and do not reveal any significant variations as a function of film thickness or grafting density. These results indicate that brushes generated by SI-ATRP are an attractive alternative to grafted-onto PEG films for the preparation of surface coatings that resist bacterial adhesion. PMID:26757483

  18. 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

  19. Hydrophobic cryogels for DNA adsorption: effect of embedding of monosize microbeads into cryogel network on their adsorptive performances.

    PubMed

    Emin Çorman, M; Bereli, Nilay; Özkara, Serpil; Uzun, Lokman; Denizli, Adil

    2013-11-01

    As alternative hydrophobic adsorbent for DNA adsorption, supermacroporous cryogel disks were synthesized via free radical polymerization. In this study, we have prepared two kinds of cryogel disks: (i) poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-tryptophan) [p(HEMA-MATrp)] cryogel containing specific hydrophobic ligand MATrp; and (ii) monosize p(HEMA-MATrp) particles synthesized via suspension polymerization embedded into p(HEMA) cryogel structure to obtain p(HEMA-MATrp)/p(HEMA) composite cryogel disks. These cryogel disks containing hydrophobic functional group were characterized via swelling studies, Fourier transform infrared spectroscopy, elemental analysis, surface area measurements and scanning electron microscopy. DNA adsorption onto both p(HEMA-MATrp) cryogel and p(HEMA-MATrp)/p(HEMA) composite cryogels was investigated. Maximum adsorption of DNA on p(HEMA-MATrp) cryogel was found to be 15 mg/g polymer. Otherwise, p(HEMA-MATrp)/p(HEMA) composite cryogels significantly increased the DNA adsorption capacity to 38 mg/g polymer. Composite cryogels could be used repeatedly without significant loss on adsorption capacity after 10 repetitive adsorption-desorption cycles. PMID:23780689

  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. Quantum chemical studies on structural, vibrational, NBO and hyperpolarizability of N-(1,1-Dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid

    NASA Astrophysics Data System (ADS)

    Renuga Devi, T. S.; Sharmi kumar, J.; Ramkumaar, G. R.

    2015-02-01

    The FTIR and FT-Raman spectra of N-(1,1-Dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid were recorded in the regions 4000-400 cm-1 and 4000-50 cm-1 respectively. The structural and spectroscopic data of the molecule in the ground state were calculated using Hartee-Fock and density functional method (B3LYP) with the correlation consistent-polarized valence double zeta (cc-pVDZ) basis set. The most stable conformer was optimized and the structural and vibrational parameters were determined based on this. With the observed FTIR and FT-Raman data, a complete vibrational assignment and analysis of the fundamental modes of the compound were carried out. Thermodynamic properties and Mulliken charges were calculated using both Hartee-Fock and density functional method using the cc-pVDZ basis set and compared. The calculated HOMO-LUMO energy gap revealed that charge transfer occurs within the molecule. 1H and 13C NMR chemical shifts of the molecule were calculated using Gauge Including Atomic Orbital (GIAO) 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 (NBO) analysis. The first order hyperpolarizability (β) and Molecular Electrostatic Potential (MEP) of the molecule was computed using DFT calculations. The electron density based local reactivity descriptor such as Fukui functions were calculated to explain the chemical reactivity site in the molecule.

  2. Synthesis, X-Ray Structure, and Characterization of Catena-bis(benzoate)bis{N,N-bis(2-hydroxyethyl)glycinate}cadmium(II)

    PubMed Central

    Katsoulakou, Eugenia; Konidaris, Konstantis F.; Raptopoulou, Catherine P.; Psyharis, Vassilis; Manessi-Zoupa, Evy; Perlepes, Spyros P.

    2010-01-01

    The reaction of N, N-bis(2-hydroxyethyl)glycine (bicine; bicH3) with Cd(O2CPh)2 · 2H2O in MeOH yielded the polymeric compound [Cd2(O2CPh)2(bicH2)2]n(1). The complex crystallizes in the tetragonal space group P41212. The lattice constants are a = b = 12.737(5) and c = 18.288(7) Å. The compound contains chains of repeating {Cd2(O2CPh)2(bicH2)2} units. One CdII atom is coordinated by two carboxylate oxygen, four hydroxyl oxygen, and two nitrogen atoms from two symmetry-related 2.21111 (Harris notation) bicH2− ligands. The other CdII atom is coordinated by six carboxylate oxygen atoms, four from two bicH2− ligands and two from the monodentate benzoate groups. Each bicinate(-1) ligand chelates the 8-coordinate, square antiprismatic CdII atom through one carboxylate oxygen, the nitrogen, and both hydroxyl oxygen atoms and bridges the second, six-coordinate trigonal prismatic CdII center through its carboxylate oxygen atoms. Compound 1 is the first structurally characterized cadmium(II) complex containing any anionic form of bicine as ligand. IR data of 1 are discussed in terms of the coordination modes of the ligands and the known structure. PMID:20976297

  3. Synthesis, X-Ray Structure, and Characterization of Catena-bis(benzoate)bis{N,N-bis(2-hydroxyethyl)glycinate}cadmium(II).

    PubMed

    Katsoulakou, Eugenia; Konidaris, Konstantis F; Raptopoulou, Catherine P; Psyharis, Vassilis; Manessi-Zoupa, Evy; Perlepes, Spyros P

    2010-01-01

    The reaction of N, N-bis(2-hydroxyethyl)glycine (bicine; bicH(3)) with Cd(O(2)CPh)(2) · 2H(2)O in MeOH yielded the polymeric compound [Cd(2)(O(2)CPh)(2)(bicH(2))(2)](n)(1). The complex crystallizes in the tetragonal space group P4(1)2(1)2. The lattice constants are a = b = 12.737(5) and c = 18.288(7) Å. The compound contains chains of repeating {Cd(2)(O(2)CPh)(2)(bicH(2))(2)} units. One Cd(II) atom is coordinated by two carboxylate oxygen, four hydroxyl oxygen, and two nitrogen atoms from two symmetry-related 2.21111 (Harris notation) bicH(2) (-) ligands. The other Cd(II) atom is coordinated by six carboxylate oxygen atoms, four from two bicH(2) (-) ligands and two from the monodentate benzoate groups. Each bicinate(-1) ligand chelates the 8-coordinate, square antiprismatic Cd(II) atom through one carboxylate oxygen, the nitrogen, and both hydroxyl oxygen atoms and bridges the second, six-coordinate trigonal prismatic Cd(II) center through its carboxylate oxygen atoms. Compound 1 is the first structurally characterized cadmium(II) complex containing any anionic form of bicine as ligand. IR data of 1 are discussed in terms of the coordination modes of the ligands and the known structure. PMID:20976297

  4. The beliefs, myths, and reality surrounding the word hema (blood) from homer to the present.

    PubMed

    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

  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. 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. PMID:19267260

  7. Evaluation of the teratological and dominant lethal potential of N,N-bis-(2-hydroxyethyl)-p-phenylenediamine sulphate in a 6-month feeding study in rats.

    PubMed

    Burnett, C M; Re, T A; Loehr, R F; Rodriguez, S C; Corbett, J F

    1986-08-01

    N,N-Bis-(2-hydroxyethyl)-p-phenylenediamine sulphate (N,N-Bis) was administered to 40 male and 45 female Sprague-Dawley rats per group by admixture with their diets at levels of 0.03, 0.1 and 0.3% for periods up to 6 months. Methaemoglobin levels were determined at wk 6. After 90 days ten animals/sex/group were killed for studies of possible target organs, haematology and blood chemistry. After 90 days, 25 females in each group were mated to untreated males in a teratology study. At wk 20, 20 males in each group were transferred from the test diets containing N,N-Bis to the control diet and were mated to untreated females in a dominant lethal study. The remaining animals were killed after 6 months for terminal studies (gross examination of organs, haematology and blood chemistry). The males used in the dominant lethal study were also killed at month 6, to serve as a comparison recovery group (gross examination of organs). Feeding of N,N-Bis at levels up to 0.3% in the diet caused a significant reduction in the body weight of male rats. The only signs of gross pathology after either 3 or 6 months of N,N-Bis feeding were darkened thyroids. This effect was noted in the high-dose group at both time intervals and, to a lesser extent, in the mid-dose group at month 6, and it was also seen in most of the high-dose recovery males and in a small number of mid-dose recovery males. No pathological effects were detected microscopically after the feeding of N,N-Bis for 90 days. N,N-Bis was not teratogenic, nor did it induce a dominant lethal effect in this study when administered to rats at levels including those causing borderline toxicity. PMID:3781436

  8. 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.

  9. Hydroxyl-functionalized 1-(2-hydroxyethyl)-3-methyl imidazolium ionic liquids: thermodynamic and structural properties using molecular dynamics simulations and ab initio calculations.

    PubMed

    Fakhraee, Mostafa; Zandkarimi, Borna; Salari, Hadi; Gholami, Mohammad Reza

    2014-12-11

    The influences of hydroxyl functional group (-OH) on the thermodynamic and structural properties of ionic liquids (ILs) composed of 1-(2-Hydroxyethyl)-3-methyl imidazolium ([C2OHmim](+)) cation and the six different conventional anions, including [Cl](-), [NO3](-), [BF4](-), [PF6](-), [TfO](-), and [Tf2N](-) have been extensively investigated using classical molecular dynamics (MD) simulations combined with ab initio calculations over a wide range of temperature (298-550 K). The volumetric thermodynamic properties, enthalpy of vaporization, cohesive energy density, Hildebrand solubility parameter, and heat capacity at constant pressure were estimated at desired temperature. The simulated densities were in good agreement with the experimental data with a slight overestimation. The interionic interaction of selected ILs was also computed using both the MD simulations and ab initio calculations. It was found that the highest association of cation and anion is attributed to [C2OHmim][Cl] followed by [C2OHmim][NO3], and [C2OHmim][Tf2N] with the bulkiest anion has the weakest interionic interaction among chosen ILs. The similar trend of interactions energies was nearly observed from cohesive energy density results. Additional structural details were comprehensively yielded by calculating radial distribution functions (RDFs) and spatial distribution function (SDFs) at 358 K. The most stable configurations of isolated and dimer ion pairs of these ILs were in excellent consistency with RDFs and SDFs results. Significant changes in arrangement of anions around the [C2OHmim](+) cation in comparison with conventional imidazolium-based ILs can be inferred from the MD simulations and ab initio results. Also, microscopic structural properties disclosed that the most strong cation-cation interaction is ascribed to the hydroxyl-functionalized ILs composed of bulkier anions, whereas ILs incorporating [Cl](-) and [NO3](-) anions are mainly involved in cation-anion interactions. The

  10. A Novel Peroxisome Proliferator-activated Receptor (PPAR)γ Agonist 2-Hydroxyethyl 5-chloro-4,5-didehydrojasmonate Exerts Anti-Inflammatory Effects in Colitis.

    PubMed

    Choo, Jieun; Lee, Yunna; Yan, Xin-Jia; Noh, Tae Hwan; Kim, Seong Jin; Son, Sujin; Pothoulakis, Charalabos; Moon, Hyung Ryong; Jung, Jee H; Im, Eunok

    2015-10-16

    Inflammatory bowel disease (IBD) is a chronic inflammatory disease with increasing incidence and prevalence worldwide. Here we investigated the newly synthesized jasmonate analogue 2-hydroxyethyl 5-chloro-4,5-didehydrojasmonate (J11-Cl) for its anti-inflammatory effects on intestinal inflammation. First, to test whether J11-Cl can activate peroxisome proliferator-activated receptors (PPARs), we performed docking simulations because J11-Cl has a structural similarity with anti-inflammatory 15-deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2), one of the endogenous ligands of PPARγ. J11-Cl bound to the ligand binding domain of PPARγ in the same manner as 15d-PGJ2 and rosiglitazone, and significantly increased transcriptional activity of PPARγ. In animal experiments, colitis was significantly reduced in mice with J11-Cl treatment, determined by analyses of survival rate, body weight changes, clinical symptoms, and histological evaluation. Moreover, J11-Cl decreased production of pro-inflammatory cytokines including IL-6, IL-8, and G-CSF as well as chemokines including chemokine (C-C motif) ligand (CCL)20, chemokine (C-X-C motif) ligand (CXCL)2, CXCL3, and chemokine (C-X3-C motif) ligand 1 (CX3CL1) in colon tissues, and LPS or TNF-α-stimulated macrophages and epithelial cells. In contrast, production of anti-inflammatory cytokines including IL-2 and IL-4 as well as the proliferative factor, GM-CSF, was increased by J11-Cl. Furthermore, inhibition of MAPKs and NF-κB activation by J11-Cl was also observed. J11-Cl reduced intestinal inflammation by increasing the transcriptional activity of PPARγ and modulating inflammatory signaling pathways. Therefore, our study suggests that J11-Cl may serve as a novel therapeutic agent against IBD. PMID:26342083

  11. Self-Assembly of Oleyl Bis(2-hydroxyethyl)methyl Ammonium Bromide with Sodium Dodecyl Sulfate and Their Interactions with Zein.

    PubMed

    Chen, Yao; Ji, Xiuling; Han, Yuchun; Wang, Yilin

    2016-08-16

    Surface tension and aggregation behavior in an aqueous solution of the mixture of cationic surfactant oleyl bis(2-hydroxyethyl)methylammonium bromide (OHAB) and anionic surfactant sodium dodecyl sulfate (SDS) have been studied by surface tension, conductivity, turbidity, zeta potential, isothermal titration microcalorimetry (ITC), cryogenic transmission electron microscopy (Cryo-TEM), and dynamic light scattering. The mixture shows pretty low critical micellar concentration and surface tension, and successively forms globular micelles, unilamellar vesicles, multilamellar vesicles, rod-like micelles, and globular micelles again by increasing the molar fraction of OHAB from 0 to 1.00. The cooperation of hydrophobic interaction between the alkyl chains, electrostatic attraction between the headgroups as well as hydrogen bonds between the hydroxyethyl groups leads to the abundant aggregation behaviors. Furthermore, the solubilization of zein by the OHAB/SDS aggregates and their interactions were studied by ITC, total organic carbon analysis (TOC), and Cryo-TEM. Compared with pure OHAB or pure SDS solution, the amount of zein solubilized by the OHAB/SDS mixture is significantly reduced. It means that the mixtures have much stronger abilities in solubilizing zein. This result has also been proved by the observed enthalpy changes for the interaction of OHAB/SDS mixture with zein. Mixing oppositely charged OHAB and SDS reduces the net charge of mixed aggregates, and thus, the electrostatic attraction between the aggregates and zein is weakened. Meanwhile, the large size of the aggregates may increase the steric repulsion to the zein backbone. This work reveals that surfactant mixtures with larger aggregates and smaller CMCs solubilize less zein, suggesting how to construct a highly efficient and nonirritant surfactant system for practical use. PMID:27452480

  12. Contact dermatitis to methyl methacrylate.

    PubMed

    Kassis, V; Vedel, P; Darre, E

    1984-07-01

    2 cases of contact dermatitis to methyl methacrylate monomer are presented. The patients are nurses who mixed bone cement at orthopedic operations. During the procedure, they used 2 pairs of gloves (latex). Butyl rubber gloves are recommended for methyl methacrylate monomer to avoid sensitization and/or cumulative irritant contact dermatitis on the hands. PMID:6204812

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

    PubMed

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

    2008-12-10

    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 ((1)H 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. PMID:21730679

  14. 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.

  15. 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

  16. Comparison of (32)P-postlabeling and high-resolution GC/MS in quantifying N7-(2-Hydroxyethyl)guanine adducts.

    PubMed

    Eide, I; Zhao, C; Kumar, R; Hemminki, K; Wu, K y; Swenberg, J A

    1999-10-01

    This study compares (32)P-postlabeling and high-resolution gas chromatography/mass spectrometry (GC/MS) in the quantification of N7-(2-hydroxyethyl)guanine adducts (7-HEG) in DNA obtained from the same tissue samples of control rats and rats exposed to ethene. The samples were obtained from two independent studies. In one study, male Sprague-Dawley rats were exposed to 300 ppm ethene for 12 h/day for 3 days ("Euro samples"). In the other study, male F-344 rats were exposed to 3000 ppm ethene for 6 h/day for 5 days ("U.S. samples"). DNA from liver and kidney from the European study was isolated in the European laboratory, and DNA from liver and spleen from the U.S. study was isolated in the U.S. laboratory. The DNA samples were coded, divided into two portions, and exchanged between the two laboratories. All DNA samples from both laboratories were analyzed with respect to 7-HEG adducts by (32)P-postlabeling and high-resolution GC/MS in the European and U.S. laboratories, respectively. However, the U.S. samples were repurified in the European laboratory before the postlabeling analysis. The data from the Euro and the U.S. samples were therefore treated separately in the regression analysis of the (32)P-postlabeling versus GC/MS data. The slope of the regression line for the Euro samples was 1.19 (r = 0.97), implying that the GC/MS data were slightly lower than the postlabeling data (one possible outlier was excluded). The slope of the regression line for the U.S. samples was 0.61 (r = 0.94), implying that the GC/MS data were somewhat higher than the postlabeling data. The main conclusion from this study is that there is very good agreement between the (32)P-postlabeling and high-resolution GC/MS methods in quantifying 7-HEG adducts to DNA, particularly when identical DNA samples are analyzed and the RNA content is <2%. The paper also discusses the background levels of adducts, the interorgan distribution, comparison between different strains, and exposure conditions

  17. 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

  18. Cellular invasion on hydrogel and poly(methyl methacrylate) implants. An in vivo study.

    PubMed

    Amon, M; Menapace, R

    1991-11-01

    Over a two-year postoperative period, cells on hydrogel (poly HEMA) and poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) were observed by specular microscopy. First small, round cells and fibroblast-like cells and later epithelioid-like cells and foreign-body giant cells could be seen on both IOL types. In eyes with prolonged postoperative inflammation a greater number of cells was observed and the cells remained on the IOL surface for a longer period. We found fewer cell reactions on hydrogel IOLs during the postoperative period of our follow-up. Foreign-body giant cells were observed on only 9%. These cells were smaller than those on PMMA IOLs. This finding may suggest that poly HEMA demonstrates greater biocompatibility, with regard to this foreign-body cell reaction, than PMMA. However, we found more pigment dispersion (50%) on the surface of hydrogel IOLs. These pigment deposits induced no cell reactions and there was less phagocytosis of the pigment debris. In 7% of the cases, dust-like, white precipitates of uncertain origin were seen; in 5% amorphous debris was seen. Fine scratches caused by polishing during the manufacturing process were seen in some cases. The postoperative clinical signs for PMMA and hydrogel IOLs were similar. PMID:1824047

  19. 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

  20. 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.

  1. 5-Aminolevulinate production by Escherichia coli containing the Rhodobacter sphaeroides hemA gene

    SciTech Connect

    Van Der Werf, M.J.; Zeikus, J.G. |

    1996-10-01

    The Rhodobacter sphaeroides hemA gene codes for 5-aminolevulinate (ALA) synthase. This enzyme catalyzes the pyridoxal phosphate-dependent condensation of succinyl coenzyme A and glycine-forming ALA. The R. sphaeroides hemA gene in the pUC18/19 vector system was transformed into Escherichia coli. The effects of both genetic and physiological factors on the expression of ALA synthase and the production of ALA were studied. ALA synthase activity levels were maximal when hemA had the same transcription direction as the lac promoter. The distance between the lac promoter and hemA affected the expression of ALA synthase on different growth substrates. The E. coli host strain used had an enormous effect on the ALA synthase activity level and on the production of ALA, with E. coli DH1 being best suited. The ALA synthase activity level was also dependent on the carbon source. Succinate, L-malate, fumarate, and L-aspartate gave the highest levels of ALA synthase activity, while the use of lactose as a carbon source resulted in a repression of ALA synthase. After growth on succinate, ALA synthase represented {approx}5% of total cellular protein. The ALA synthase activity level was also dependent on the pH of the medium, with maximal activity occurring at pH 6.5. ALA production by whole cells was limited by the availability of glycine, and the addition of 2 g of glycine per liter to the growth medium increased the production of ALA fivefold, to 2.25 mM. In recombinant E. coli extracts, up to 22 mM ALA was produced from succinate, glycine, and ATP. 58 refs., 4 figs., 7 tabs.

  2. Preparation and characterization of silanized poly(HEMA) nanoparticles for recognition of sugars.

    PubMed

    Kuru, Cansu İlke; Türkcan, Ceren; Uygun, Murat; Okutucu, Burcu; Akgöl, Sinan

    2016-05-01

    In this study presented, p(HEMA) nanoparticles were synthesized by the emulsion polymerization technique and then activated by a silanization agent, 3-aminopropyltriethoxysilane (APTES). The APTES-functionalized p(HEMA) nanoparticles that were synthesized were characterized by studies using the Zetasizer, FTIR and SEM. The p(HEMA)-APTES nanoparticles were further modified with phenyl boronic acid (PBA), and these boronate affinity nanoparticles were used for the recognition of some sugars such as galactose, fructose and raffinose. The system parameters (temperature and initial sugar concentration) were optimized for maximum sugar adsorption. The maximum amount of galactose, fructose, and raffinose adsorbed were found to be 4334.5 mg/g; 4334.9 and 810.0 mg/g, respectively (at 25°C, in a phosphate buffer of pH 7.0). Considering the results of this study, it can be concluded that these nanoparticles may be used as a new alternative for the specific recognition of sugar. PMID:25465044

  3. [The Hedonic and Eudaimonic Motives for Activities (HEMA) in Japan: the pursuit of well-being].

    PubMed

    Asano, Ryosuke; Igarashi, Tasuku; Tsukamoto, Saori

    2014-04-01

    Hedonia (seeking pleasure and relaxation) and eudaimonia (seeking to improve oneself in congruence with one's values) uniquely contribute to well-being. The authors developed and tested the construct validity of a Japanese version of the Hedonic and Eudaimonic Motives for Activities (HEMA) scale that had been originally developed in North America. Drawing on the theoretical and empirical evidence from research on emotion, we proposed that people would pursue well-being in three different directions: pleasure, relaxation, and eudaimonia. In Study 1, we used the original HEMA scale to examine the Japanese attainment of well-being. The results supported the hypothesized three-factor model. Study 2 revealed that the Japanese version of the HEMA scale measured pleasure, relaxation, and eudaimonia. Each of these subscales showed statistically sufficient internal consistency. There was no gender difference in any of these measures. Scores on the scale systematically corresponded with external criterion variables, such as life satisfaction, affect, Ryff's psychological well-being, social support, and lifestyle. Implications for psychological research and public policies that cover the topic of the pursuit of well-being are discussed. PMID:24804432

  4. 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.

  5. 3D Microperiodic Hydrogel Scaffolds for Robust Neuronal Cultures

    PubMed Central

    Hanson Shepherd, Jennifer N.; Parker, Sara T.; Shepherd, Robert F.; Gillette, Martha U.; Lewis, Jennifer A.; Nuzzo, Ralph G.

    2011-01-01

    Three-dimensional (3D) microperiodic scaffolds of poly(2-hydroxyethyl methacrylate) (pHEMA) have been fabricated by direct-write assembly of a photopolymerizable hydrogel ink. The ink is initially composed of physically entangled pHEMA chains dissolved in a solution of HEMA monomer, comonomer, photoinitiator and water. Upon printing 3D scaffolds of varying architecture, the ink filaments are exposed to UV light, where they are transformed into an interpenetrating hydrogel network of chemically cross-linked and physically entangled pHEMA chains. These 3D microperiodic scaffolds are rendered growth compliant for primary rat hippocampal neurons by absorption of polylysine. Neuronal cells thrive on these scaffolds, forming differentiated, intricately branched networks. Confocal laser scanning microscopy reveals that both cell distribution and extent of neuronal process alignment depend upon scaffold architecture. This work provides an important step forward in the creation of suitable platforms for in vitro study of sensitive cell types. PMID:21709750

  6. 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.

  7. Mechanism of reduction of bis(2-hydroxyethyl) trisulfide by e/sub aq//sup -/ and. CO/sub 2//sup -/. Spectrum and scavenging of RSS. radicals. [Electron beams and gamma rays

    SciTech Connect

    Wu, Z.; Back, T.G.; Ahmad, R.; Yamdagni, R.; Armstrong, D.A.

    1982-10-28

    Each of the reducing radicals e/sub aq//sup -/, .CO/sub 2//sup -/, and (CH/sub 3/)/sub 2/COH cleaves bis(2-hydroxyethyl) trisulfide in aqueous solution to produce (2-hydroxyethyl)perthiyl (RSS.) radicals and 2-hydroxyethanethiol. The RSS. radical had lambda/sub max/ = 374 nm, epsilon/sub max/ = 1630 +- 50 M/sup -1/ cm/sup -1/, and a second-order rate constant for dimerization 2k/sub 12/ = (1.4 +- 0.3) x 10/sup 9/ M/sup -1/s/sup -1/ (2RSS. ..-->.. RS/sub 4/R (12)). It is able to abstract H atoms from dihydroflavin adenine dinucleotide (FH/sub 2/), but not from formate. Thus, in aqueous solution D/sub RSS-H/ must be greater than 60 but less than 90 kcal mol/sup -1/. Although tetrasulfide and thiol are the major initial products of reduction, secondary thermal reactions occur and produce sulfanes (RS/sub n/H) and polysulfides (RS/sub n/R). In the early stages of reduction products of n = 2 dominate. However, on prolonged reaction with .CO/sub 2//sup -/ elemental sulfur is precipitated, and this is probably formed by elimination from sulfanes with n much larger and in the region of 8.

  8. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... methacrylate and substituted methacrylate. 721.9492 Section 721.9492 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate. Link to an amendment published at 79 FR 34638, June 18, 2014....

  9. 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.

  10. Lack of genotoxic properties of the hair-dye component N-methyl-amino-2-nitro-4-N',N'-bis-(2-hydroxyethyl)-aminobenzene, in mammalian cells in vitro, and in yeasts.

    PubMed

    Loprieno, N; Mariani, L; Rusciano, D

    1983-02-01

    N-Methyl-amino-2-nitro-4-N',N'-bis-(2-hydroxyethyl)-aminobenzene is a hair-dye ingredient. Its potential ability to induce gene mutations, in the yeast S. pombe and in cultured mammalian CH-V79 cells, mitotic gene conversion in the yeast S. cerevisiae, and unscheduled DNA synthesis in cultured human HeLa cells was evaluated. The chemical proved unable to induce detectable genotoxic effects according to these tests. The present data, together with others that show that the chemical is not mutagenic in Salmonella typhimurium or Drosophila, and is not clastogenic in mammalian cytogenetic assays (in vitro or in vivo), strongly support the non-genotoxicity of the chemical. PMID:6402693

  11. Preparation and Properties of Novel Dentin Adhesives with Esterase Resistance

    PubMed Central

    Park, Jong-Gu; Ye, Qiang; Topp, Elizabeth M.; Kostoryz, Elisabet L.; Wang, Yong; Kieweg, Sarah L.; Spencer, Paulette

    2012-01-01

    A new methacrylate monomer, trimethylolpropane mono allyl ether dimethacrylate (TMPEDMA), was synthesized and evaluated. This branched methacrylate was designed to increase esterase-resistance when incorporated into conventional HEMA (2-hydroxyethyl methacrylate)/BisGMA (2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane) dental adhesives. The new adhesives, HEMA/BisGMA/TMPEDMA in a 45/30/25 (w/w) ratio were formulated with H2O at 0 (A0T) and 8 wt % water (A8T) and compared with control adhesives (HEMA/BisGMA, 45/55 (w/w), at 0 (A0) and 8 wt % (A8) water). Camphoroquinone (CQ), 2-(dimethylamino) ethyl methacrylate and diphenyliodonium hexafluorophosphate were used as photoinitiators. The new adhesives showed a degree of conversion comparable with the control and improved modulus and glass transition temperature (Tg). Exposure of photopolymerized discs to porcine liver esterase for up to eight days showed that the net cumulative methacrylic acid (MAA) release in adhesives formulated with the new monomer and 8% water (A8T: 182 μg/mL) was dramatically (P < 0.05) decreased in comparison to the control (A8: 361.6 μg/mL). The results demonstrate that adhesives made with the new monomer and cured in water to simulate wet bonding are more resistant to esterase than conventional HEMA/BisGMA adhesive. PMID:22919119

  12. Synthesis of poly(alkenoic acid) with L-leucine residue and methacrylate photopolymerizable groups useful in formulating dental restorative materials.

    PubMed

    Buruiana, Tinca; Nechifor, Marioara; Melinte, Violeta; Podasca, Viorica; Buruiana, Emil C

    2014-01-01

    To develop resin-modified glass ionomer materials, we synthesized methacrylate-functionalized acrylic copolymer (PAlk-LeuM) derived from acrylic acid, itaconic acid and N-acryloyl-L-leucine using (N-methacryloyloxyethylcarbamoyl-N'-4-hydroxybutyl) urea as the modifying agent. The spectroscopic (proton/carbon nuclear magnetic resonance, Fourier transform infrared spectroscopy) characteristics, and the gel permeation chromatography/Brookfield viscosity measurements were analysed and compared with those of the non-modified copolymer (PAlk-Leu). The photocurable copolymer (PAlk-LeuM, ~14 mol% methacrylate groups) and its precursor (PAlk-Leu) were incorporated in dental ionomer compositions besides diglycidyl methacrylate of bisphenol A (Bis-GMA) or an analogue of Bis-GMA (Bis-GMA-1), triethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate. The kinetic data obtained by photo-differential scanning calorimetry showed that both the degree of conversion (60.50-75.62%) and the polymerization rate (0.07-0.14 s(-1)) depend mainly on the amount of copolymer (40-50 wt.%), and conversions over 70% were attained in the formulations with 40 wt.% PAlk-LeuM. To formulate light-curable cements, each organic composition was mixed with filler (90 wt.% fluoroaluminosilicate/10 wt.% hydroxyapatite) into a 2.7:1 ratio (powder/liquid ratio). The light-cured specimens exhibited flexural strength (FS), compressive strength (CS) and diametral tensile strength (DTS) varying between 28.08 and 64.79 MPa (FS), 103.68-147.13 MPa (CS) and 16.89-31.87 MPa (DTS). The best values for FS, CS and DTS were found for the materials with the lowest amount of PAlk-LeuM. Other properties such as the surface hardness, water sorption/water solubility, surface morphology and fluorescence caused by adding the fluorescein monomer were also evaluated. PMID:24701975

  13. 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.

  14. Purification of papain using reactive green 5 attached supermacroporous monolithic cryogel.

    PubMed

    Uygun, Deniz Aktaş; Akduman, Begüm; Uygun, Murat; Akgöl, Sinan; Denizli, Adil

    2012-06-01

    Supermacroporous poly(2-hydroxyethyl methacrylate) [poly(HEMA)] monolithic cryogel was prepared by radical cryocopolymerization of HEMA with N,N'-methylene bisacrylamide as crosslinker. Reactive Green 5 dye was immobilized to the cryogel with nucleophilic substitution reaction, and this dye attached cryogel column was used for affinity purification of papain from Carica papaya latex. Reactive Green 5-immobilized poly(HEMA) cryogel was characterized by swelling studies, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis. Maximum papain adsorption capacity was found to be 68.5 mg/g polymer while nonspecific papain adsorption onto plain cryogel was negligible (3.07 mg/g polymer). Papain from C. papaya was purified 42-fold in single step with dye attached cryogel, and purity of papain was shown by silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PMID:22573009

  15. 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.

  16. 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

  17. 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.

  18. Enhancemet of flow boiling heat transfer in pHEMA/pPFDA coated microtubes with longitudinal variations in wettability

    NASA Astrophysics Data System (ADS)

    Nedaei, Masoumeh; Armagan, Efe; Sezen, Meltem; Ozaydin Ince, Gozde; Kosar, Ali

    2016-03-01

    Flow boiling heat transfer was investigated in stainless steel hypodermic microtubes, whose surfaces were enhanced by gradient crosslinked polyhydroxyethylmethacrylate (pHEMA)/polyperfluorodecylacrylate (pPFDA) coatings thereby offering variations in wettability along the surface as well as high porosity. The initiated chemical vapor deposition (iCVD) method was implemented for coating the inner walls of the microtubes with an inner diameter of 502 μm, and deionized water was used as the working fluid. Experimental results were obtained from the coated microtubes, where one end corresponded to the pHEMA (hydrophilic) coated part and the other end was the most hydrophobic location with the pPFDA (hydrophobic) coating so that wettability varied along the length of the microtube. The results of both the hydrophobic and hydrophilic inlet cases were compared to their plain surface counterparts at the mass flux of 9500 kg/m2s. The experimental results showed a remarkable increase in boiling heat transfer with the coatings. The highest heat transfer coefficients were attained for the pHEMA coated (hydrophobic inlet and hydrophilic outlet) outlet case with a maximum heat transfer enhancement ratio of ˜64%. The reason for the enhanced heat transfer with the coated microtubes can be attributed to the increased nucleation site density and bubble release as well as enhanced convection and bubble motion near the surface due to the variation in wettability along the length. The results proved that gradient pHEMA/pPFDA coatings can be utilized as a viable surface enhancement method in microscale cooling applications.

  19. 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...

  20. Formation of gel of preformed size-selected titanium-oxo-alkoxy nanoparticles: towards organic-inorganic hybrid material with efficient interfacial electron transfer

    NASA Astrophysics Data System (ADS)

    Gorbovyi, Pavlo; Uklein, Andrii; Traore, Mamadou; Museur, Luc; Kanaev, Andrei

    2014-12-01

    We report on preparation of a new organic-inorganic hybrid material with high photonic sensitivity, of which the inorganic component is gel of preformed size-selected titanium-oxo-alkoxy (TOA) nanoparticles. The inorganic nanoparticles of 5 nm size are generated in perfect micromixing conditions and assembled into the gel network in monomer HEMA (2-hydroxyethyl methacrylate) solutions at sufficiently slow input of water molecules in neutral pH conditions. The gelation is found to compete with precipitation and is promoted by an increase of the nanoparticle concentration. As a result, homogeneous optical-grade gels are obtained at titanium molar concentrations of 1.5 M and higher. After the organic polymerization, the organicinorganic pHEMA-TOA hybrids (pHEMA = poly(2-hydroxyethyl methacrylate)) show a high quantum yield of photoinduced charges separation (Ti3+/absorbed photons) and storage capacity (Ti3+/Ti4+), respectively 75% and 25%, which confirm the importance of the material nanoscale morphology control.

  1. Performance of a cyanobacteria whole cell-based fluorescence biosensor for heavy metal and pesticide detection.

    PubMed

    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

  2. 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

  3. 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

  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. PMID:26394068

  5. 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

  6. Photolithography with polymethyl methacrylate (PMMA)

    NASA Astrophysics Data System (ADS)

    Carbaugh, Daniel J.; Wright, Jason T.; Parthiban, Rajan; Rahman, Faiz

    2016-02-01

    Polymethyl methacrylate (PMMA) is widely used as an electron beam resist but is not used as a photoresist because of its insensitivity to electromagnetic radiation with wavelengths longer than about 300 nm. In this paper we describe a technique for performing conventional photolithography with high molecular weight PMMA at the widely used 365 nm i-line wavelength. The technique involves photosensitizing PMMA with Irgacure 651—a commercially available photo-initiator that can cause PMMA strands to cross-link. Optimum amount of Irgacure can produce a negative tone photoresist with adequate photosensitivity and plasma etch resistance. We describe this technique in detail with complete processing conditions and discuss the effects of varying Irgacure 651 concentration in PMMA as well as changes in UV exposure dose. We also show example structures patterned with commonly available materials and equipment. Finally, we show that it is possible to carry out gradient lithography with this approach, in order to produce structures in relief in photosensitive PMMA.

  7. Functionalization of cotton fabrics by radiation induced grafting of quaternary salt to impart antibacterial property

    NASA Astrophysics Data System (ADS)

    Goel, N. K.; Kumar, Virendra; Rao, M. S.; Bhardwaj, Y. K.; Sabharwal, S.

    2011-11-01

    High energy gamma radiation has been used to covalently link polymer chains of a quaternary ammonium salt containing monomer, viz. [2-(Acryloyloxyethyl)]trimethylammonium chloride (AETC) to cotton fabric by mutual radiation grafting using 2-hydroxyethyl methacrylate (2-HEMA) monomer as the grafting facilitator. Grafting yield was found to increase with the radiation dose and monomer concentration. The grafted samples have been characterized for water uptake, surface morphology and thermal stability and for their antibacterial efficacy against various bacteria and were found to possess significant antibacterial activity particularly against gram-positive bacteria.

  8. Radiation graft modification of ethylene-propylene rubber—II. Effect of additives

    NASA Astrophysics Data System (ADS)

    Haddadi-Asl, V.; Burford, R. P.; Garnett, J. L.

    1995-02-01

    The effect of multifunctional acrylic additives including TMPTA, PEGDA and PGTA on the radiation grafting of hydrophilic vinyl monomers onto ethylene—propylene elastomer (EPM rubbers) was studied. This work centres upon gamma irradiation-induced grafting of acrylamide (AAm), N-vinyl-2-pyrrolidone (NVP), 2-hydroxyethyl methacrylate (HEMA) and acrylonitrile (AN) onto EPM rubber by the simultaneous method. Water proved to be an effective solvent but methanol lowered grafting. Sulphuric acid was detrimental to both homopolymerisation and grafting, a result consistent with the theory proposed for the role of this additive in polymer grafting systems.

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  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. Polymerization of novel methacrylated anthraquinone dyes

    PubMed Central

    Dollendorf, Christian; Kreth, Susanne Katharina; Choi, Soo Whan

    2013-01-01

    Summary A new series of polymerizable methacrylated anthraquinone dyes has been synthesized by nucleophilic aromatic substitution reactions and subsequent methacrylation. Thereby, green 5,8-bis(4-(2-methacryloxyethyl)phenylamino)-1,4-dihydroxyanthraquinone (2), blue 1,4-bis(4-((2-methacryloxyethyl)oxy)phenylamino)anthraquinone (6) and red 1-((2-methacryloxy-1,1-dimethylethyl)amino)anthraquinone (12), as well as 1-((1,3-dimethacryloxy-2-methylpropan-2-yl)amino)anthraquinone (15) were obtained. By mixing of these brilliant dyes in different ratios and concentrations, a broad color spectrum can be generated. After methacrylation, the monomeric dyes can be covalently emplaced into several copolymers. Due to two polymerizable functionalities, they can act as cross-linking agents. Thus, diffusion out of the polymer can be avoided, which increases the physiological compatibility and makes the dyes promising compounds for medical applications, such as iris implants. PMID:23503994

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. (Methacrylates to form insulation). Final technical report

    SciTech Connect

    Rasmussen, L.

    1980-05-20

    The use of methacrylates to form the interior foam of a transport insulation was studied. Problems encountered with the methacrylates include its low surface tension, and its slow rate of polymerization. An additional problem was an incompatability between the fluorinated surfactant molecules and the fluorocarbon gas used to blow the foam. Other experimentation involved acrylamide foams using glycerol-ethylene glycol combinations and sodium linolenate. Also investigated was the use of tin oxide coatings which are transported to visible light but reflect infrared light. (BCS)

  1. Anionic polymerization of azo substituted methacrylates

    SciTech Connect

    Dimov, D.K.; Dalton, L.R.; Hogen-Esch, T.E.

    1993-12-31

    The anionic polymerization of 4-phenylazophenyl methacrylate (PAM) and 6-(4-phenylazophenoxy)-hexyl methacrylate (PAHM) initiated by {open_quotes}living{close_quotes} PMMA with lithium counterion was studied in THF at {minus}78{degrees}C. The polymerization of PAM was prevented by a side termination reaction. The polymerization of PAHM proceeded smoothly to furnish PMMA/azopolymer block copolymers. The process showed features typical of {open_quotes}living{close_quotes} anionic polymerization. No phase transitions could be detected by DSC to prove liquid crystalline mesophase formation by the block copolymers.

  2. 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.

  3. pH-sensitive methacrylic copolymers and the production thereof

    DOEpatents

    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.

  4. 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...

  5. 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...

  6. 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...

  7. Thermodynamic properties and ideal-gas enthalpies of formation for dicyclohexyl sulfide, diethylenetriamine, di-n-octyl sulfide, dimethyl carbonate, piperazine, hexachloroprop-1-ene, tetrakis(dimethylamino)ethylene, N,N{prime}-bis-(2-hydroxyethyl)ethylenediamine, and 1,2,4-triazolo[1,5-a]pyrimidine

    SciTech Connect

    Steele, W.V.; Chirico, R.D.; Knipmeyer, S.E.; Nguyen, A.; Smith, N.K.

    1997-11-01

    The results of the study are aimed at improvement of group-contribution methodology for estimation of thermodynamic properties of organic substances. Specific weaknesses where particular group-contribution terms were unknown, or estimated because of lack of experimental data, are addressed by experimental studies of enthalpies of combustion in the condensed phase, vapor-pressure measurements, and differential scanning calorimetric (DSC) heat-capacity measurements. Ideal-gas enthalpies of formation of hexachloroprop-1-ene, N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, dimethyl carbonate, di-n-octyl sulfide, dicyclohexyl sulfide, diethylenetriamine, tetrakis(dimethylamino)ethylene, piperazine, and 1,2,4-triazolo[1,5-a]pyrimidine are reported. Enthalpies of fusion were determined for N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, piperazine and 1,2,4-triazolo[1,5-a]pyrimidine. Two-phase (solid + vapor) or (liquid + vapor) heat capacities were determined from 300 K to the critical region or earlier decomposition temperature for each compound studied. Liquid-phase densities along the saturation line were measured for N,N{prime}-bis(2-hydroxyethyl)ethylenediamine, dimethyl carbonate, and dicyclohexyl sulfide. For dimethyl carbonate and piperazine, critical temperatures and critical densities were determined from the DSC results and corresponding critical pressures derived from the fitting procedures. Fitting procedures were used to derive critical temperatures, critical pressures, and critical densities for hexachloroprop-1-ene, di-n-octyl sulfide, dicyclohexyl sulfide, and diethylenetriamine. Group-additivity parameters and 1,4-interaction terms useful in the application of group-contribution correlations were derived.

  8. Surface elasticity and charge concentration-dependent endothelial cell attachment to copolymer polyelectrolyte hydrogel.

    PubMed

    Kim, Seonghwan; English, Anthony E; Kihm, Kenneth D

    2009-01-01

    The surface micromechanical properties of 2-hydroxyethyl methacrylate (HEMA) and 2-methacryloxyethyl trimethyl ammonium chloride (MAETAC) copolymer hydrogels are probed using atomic force microscopy. HEMA-MAETAC polyelectrolyte hydrogels with increasing positive charge concentrations ranging from 0 to 400mM in increments of 40mM, are fabricated using different proportions of HEMA and MAETAC monomers. Increasing proportions of positively charged MAETAC monomers produce hydrogels with increasingly swollen states and correspondingly decreasing measures of stiffness, or Young's modulus. Increasing the relative proportion of charged monomers also increases the hysteresis in the approaching and retracting components of the force spectroscopy curves. When these hydrogels are equilibrated in cell-culture media without fetal bovine serum and a pH-controlled CO(2) environment, precipitation reactions increase the variability of the Young's modulus estimates. Adding a buffer, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, maintains physiological pH without the use of a CO(2) environment, and thus reduces salt precipitation reactions and the variability of the Young's modulus. The attachment of porcine pulmonary artery endothelial cells increases with increasing prepared hydrogel charge concentration and decreasing elasticity. PMID:18774763

  9. Synthesis and characterisation of macroporous poly(methyl methacrylate) with plasma-polymerised hydrophilic coating

    NASA Astrophysics Data System (ADS)

    Serrano Aroca, Angel

    This thesis focuses on the synthesis and characterisation of a new macroporous biomatenal made of poly(methyl methacrylate) and plasma-polymerised poly(hydroxyethyl acrylate). A series of porous and non-porous PMMA networks with different degrees of porosity and cross-linker contents were synthesised by polymerisation in the presence of ethanol and bulk polymerisation. Macroporous PMMA was allowed to adsorb 2-hydroxyethyl acrylate monomer vapour. The absence of thermal or photoinitiators makes difficult the initiation of the polymerisation process of the adsorbed monomer. However, by plasma treatment this problem can be solved. This method of forming a pure hydrophilic coating by plasma polymerisation is very interesting because the porosity of the scaffold hardly changes at the end of the process. The DMS spectrum shows that these materials are a new kind of macroporous hydrogel with a high mechanical modulus at room temperature and able to adsorb water while keeping their mechanical properties. Takayanagi's block model was applied to these results to characterise the biphasic behaviour of these systems. Porosity measurements were performed to determine the volume fraction of pores in the samples before and after the plasma treatment. The structure and morphology of these macroporous systems were observed by Scanning Electron Microscope (SEM). The nature, homogeneity and stability of the hydrophilic coating was studied by DSC, ATR FTIR, TGA and immersion in water. It was found that the plPHEA is very stable and only in very drastic conditions (boiling water) can suffer hydrolytic degradation. The water sorption and diffusion properties of these biomaterials were studied by dynamic desorption, contact angle, equilibrium sorption isotherms and immersion experiments. Thermal analysis of water in the hydrophilic layer was performed by DSC. All these experimental techniques suggested that the plasma-polymerised PHEA is more homogeneously interpenetrated with

  10. 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

  11. 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.

  12. "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. PMID:27509015

  13. Monitoring the transformation of colloidal crystals by styrene vapor using atomic force microscopy.

    PubMed

    Qin, Dongqi; Tan, Susheng; Qin, Shuhui; Ford, Warren T

    2004-04-13

    The stages of transformation of a colloidal crystalline film of latex spheres to a new periodic structure were imaged by atomic force microscopy. Colloidal crystalline films were prepared with 320 nm diameter poly(styrene-co-2-hydroxyethyl methacrylate) (PSt/HEMA) spheres. The hexagonally ordered surfaces of the colloidal crystalline films were transformed with styrene vapor at room temperature to a new morphology having holes in the surface and the same periodicity as the original films. The surfaces of colloidal crystals and the transformed films have a raspberry-like texture superposed on the 320 nm hexagonal periodicity. Both height images and phase images reveal that the latex spheres shrink and the transformation proceeds by an order-disorder-order sequence. The final structure is an interconnected colloidal array with smaller polystyrene particles dispersed in a continuous PSt/HEMA matrix. PMID:15875841

  14. 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

  15. The preparation of the chronic hyper-endotoxemia experimental animal model by means of a drug delivery system.

    PubMed

    Kakinoki, S; Yukutake, K; Kaetsu, I; Uchida, K; Sutani, K; Kosumi, T; Usui, N; Yonekura, T; Kubota, A; Ohyanagi, H

    2001-07-10

    A drug delivery system (DDS) consisting of lipopolysaccharide (LPS) as a drug and 2-hydroxyethyl methacrylate (HEMA)-diethylene glycol dimethacrylate (2G) or -polyethylene glycol dimethacrylate (4G, 9G) copolymer was prepared, and used for the efficient preparation of an experimental animal model of chronic hyper-endotoxemia. The release profiles of LPS in the in-vitro test were greatly influenced by the composition of HEMA-2G, 4G, 9G in the copolymer. It was found that LPS release from the DDS continued gradually and constantly throughout 2 weeks. In the in-vivo experiment with rats, the DDS maintained a high blood concentration level of LPS for 3 days. These results strongly suggest the possibility of convenient and reproducible preparation of a chronic hyper-endotoxemia animal model. PMID:11451506

  16. 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.

  17. Determination of binary pesticide mixtures by an acetylcholinesterase-choline oxidase biosensor.

    PubMed

    Kok, Fatma N; Hasirci, Vasif

    2004-02-15

    In this study, acetylcholinesterase (AChE) and choline oxidase (ChO) were co-immobilized on poly(2-hydroxyethyl methacrylate) (pHEMA) membranes to construct a biosensor for the detection of anti-cholinesterase compounds. pHEMA membranes were prepared with the addition of SnCl(4) to achieve the desired porosity. Immobilization of the enzymes was done by surface attachment via epichlorohydrin (Epi) and Cibacron Blue F3G-A (CB) activation. Enzyme immobilized membrane was used in the detection of anti-cholinesterase activity of aldicarb (AS), carbofuran (CF) and carbaryl (CL), as well as two mixtures, (AS+CF) and (AS+CL). The total anti-cholinesterase activity of binary pesticide mixtures was found to be lower than the sum of the individual inhibition values. PMID:14709383

  18. Adsorption isotherms, kinetics, thermodynamics and desorption studies for uranium and thorium ions from aqueous solution by novel microporous composite P(HEMA-EP)

    NASA Astrophysics Data System (ADS)

    Akkaya, Recep; Akkaya, Birnur

    2013-03-01

    In this research, a novel composite, poly(2-hydroxyethylmethacrylate-expanded perlite) [P(HEMA-EP)], was synthesized and its adsorptive features were investigated. P(HEMA-EP)'s adsorptive features were evaluated for UO22+ and Th4+ ions in terms of the dependency upon the ion concentration, pH, temperature, and time. P(HEMA-EP) was able to bind UO22+ and Th4+ ions with strong chemical affinity. The adsorption results were fitted to the classical Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) sorption models. P(HEMA-EP) was also used to study the removal of UO22+ and Th4+ ions from aqueous solutions in a batch system. The adsorption capacity (XL) of UO22+ and Th4+ ions was found to be 0.29 and 0.44 mol kg-1, respectively. The kinetic data corresponds well to the pseudo-second-order equation. Changes in the enthalpy and entropy values demonstrated that the overall adsorption process was spontaneous (ΔG < 0), endothermic (ΔH > 0), and had increased entropy (ΔS > 0), as expected. The reusability of the composites was confirmed for five sequential reuses.

  19. Reduced lymphocyte activation in space: role of cell-substratum interactions.

    PubMed

    Gmünder, F K; Kiess, M; Sonnenfeld, G; Lee, J; Cogoli, A

    1992-01-01

    We investigated the effect of substratum adhesiveness on stimulated lymphocyte blastogenesis by reducing and blocking cell adhesion with poly (2-hydroxyethyl methacrylate) (poly-HEMA) 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% of the control (tissue culture plastic). Interferon-gamma production was near zero when the cells were grown on the least adhesive substratum. On uncoated plastic, activated lymphocytes subjected to high gravity (20g) exhibited an increased proliferation rate (40%) compared with 1g. By contrast, on poly-HEMA, high gravity did not improve lymphocyte responsiveness. These results show that activated lymphocytes need to anchor and spread prior to achieving an optimal proliferation response. We conclude that decreased lymphocyte adhesion could contribute to the depressed in vitro lymphocyte responsiveness found in the microgravity conditions of space flight. PMID:11536989

  20. Surface Modification of a Perfluorinated Ionomer Using a Glow Discharge Deposition Method to Control Protein Adsorption

    PubMed Central

    Valdes, T.I.; Ciridon, W.; Ratner, B.D.; Bryers, J.D.

    2008-01-01

    Nafion™ is the membrane material preferred for in situ glucose sensors. Unfortunately, surface properties of Nafion promote random protein adsorption and eventual foreign body encapsulation thus leading to loss if glucose signal over time. Here we detail surface modifications made by RF plasma deposition to Nafion with the intent to prevent random protein adsorption while providing enough functional sites (hydroxyl groups) to bind a biologically active peptide known to induce cellular adhesion (YRGDS). Nafion surfaces were modified by RF plasma polymerizing five different combinations of (1) tetraethylene glycol dimethyl ether (tetraglyme) and (2) 2-hydroxyethyl methacrylate (HEMA): pure tetraglyme, 2.5% HEMA/97.5% tetraglyme; 5% HEMA/95% tetraglyme, 10% HEMA/90% tetraglyme; and pure HEMA. Resultant surfaces were characterized by XPS (low and high resolution), dynamic contact angle, and atomic force microscopy. Protein adsorption and retention was determined and correlated to surface layer composition. The ability to bind a cell adhesion peptide was also determined and correlated well with surface layer composition. PMID:18155292

  1. 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.

  2. Triazacryptand-based fluorescent sensors for extracellular and intracellular K+ sensing.

    PubMed

    Zhou, Xianfeng; Su, Fengyu; Gao, Weimin; Tian, Yanqing; Youngbull, Cody; Johnson, Roger H; Meldrum, Deirdre R

    2011-11-01

    A 4-amino-naphthalimide derived fluorophore with a triazacryptand moiety ligand was synthesized as a potassium ion (K(+)) sensor (KS1). This sensor is a monomer possessing a polymerizable vinyl group. By taking advantage of the polymerizable characteristics of the vinyl group, KS1 was polymerized with 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AM) to form K(+) sensing films for extracellular sensing. The sensitivity of the films to potassium ions can be further tuned through the adjustment of the HEMA and AM weight ratios as well as introduction of positive or negative charge-containing segments. KS1 and its poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) (PHEMA-co-PAM) thin films show high selectivity for K(+) over competing sodium ions (Na(+)) at physiological concentrations. Extracellular sensing was demonstrated using a KS1-conjugated PHEMA-co-PAM thin film to measure the K(+) efflux of Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) stimulated by lysozyme. Meanwhile, KS1 itself permeates human glioblastoma U87MG and human esophagus premalignant CP-A cell lines. KS1 was used to monitor K(+) efflux stimulated by adenosine-5'-triphosphate (ATP), amphotericin, and a mixture of nigericin, bumetanide and ouabain, demonstrating application of this material as an intracellular potassium ion sensor. PMID:21855134

  3. 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

    2014-12-01

    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. PMID:25390070

  4. 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

  5. Zwitterionic poly(amino acid methacrylate) brushes.

    PubMed

    Alswieleh, Abdullah M; Cheng, Nan; Canton, Irene; Ustbas, Burcin; Xue, Xuan; Ladmiral, Vincent; Xia, Sijing; Ducker, Robert E; El Zubir, Osama; Cartron, Michael L; Hunter, C Neil; Leggett, Graham J; Armes, Steven P

    2014-07-01

    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

  6. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  7. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  8. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  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. 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

  12. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  13. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  14. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  15. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  16. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  17. 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...

  18. Regioselective ester cleavage during the preparation of bisphosphonate methacrylate monomers

    PubMed Central

    Chougrani, Kamel; Niel, Gilles; Boutevin, Bernard

    2011-01-01

    Summary New functional monomers bearing a methacrylate, a bisphosphonate function and, for most, an internal carboxylate group, were prepared for incorporation into copolymers with adhesive or anticorrosive properties. Methanolysis of some trimethylsilyl bisphosphonate esters not only deprotects the desired bisphosphonate function but also regioselectively cleaves the alkyl ester function without affecting the methacrylate ester. PMID:21512600

  19. Cell-laden microengineered gelatin methacrylate hydrogels.

    PubMed

    Nichol, Jason W; Koshy, Sandeep T; Bae, Hojae; Hwang, Chang M; Yamanlar, Seda; Khademhosseini, Ali

    2010-07-01

    The cellular microenvironment plays an integral role in improving the function of microengineered tissues. Control of the microarchitecture in engineered tissues can be achieved through photopatterning of cell-laden hydrogels. However, despite high pattern fidelity of photopolymerizable hydrogels, many such materials are not cell-responsive and have limited biodegradability. Here, we demonstrate gelatin methacrylate (GelMA) as an inexpensive, cell-responsive hydrogel platform for creating cell-laden microtissues and microfluidic devices. Cells readily bound to, proliferated, elongated, and migrated both when seeded on micropatterned GelMA substrates as well as when encapsulated in microfabricated GelMA hydrogels. The hydration and mechanical properties of GelMA were demonstrated to be tunable for various applications through modification of the methacrylation degree and gel concentration. The pattern fidelity and resolution of GelMA were high and it could be patterned to create perfusable microfluidic channels. Furthermore, GelMA micropatterns could be used to create cellular micropatterns for in vitro cell studies or 3D microtissue fabrication. These data suggest that GelMA hydrogels could be useful for creating complex, cell-responsive microtissues, such as endothelialized microvasculature, or for other applications that require cell-responsive microengineered hydrogels. PMID:20417964

  20. 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. PMID:24268272

  1. 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

  2. pHEMA Encapsulated PEDOT-PSS-CNT Microsphere Microelectrodes for Recording Single Unit Activity in the Brain.

    PubMed

    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

  3. 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

  4. 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.

  5. Predicting the chromatographic retention of polymers: poly(methyl methacrylate)s and polyacryate blends.

    PubMed

    Bashir, Mubasher A; Radke, Wolfgang

    2007-09-01

    The suitability of a retention model especially designed for polymers is investigated to describe and predict the chromatographic retention behavior of poly(methyl methacrylate)s as a function of mobile phase composition and gradient steepness. It is found that three simple yet rationally chosen chromatographic experiments suffice to extract the analyte specific model parameters necessary to calculate the retention volumes. This allows predicting accurate retention volumes based on a minimum number of initial experiments. Therefore, methods for polymer separations can be developed in relatively short time. The suitability of the virtual chromatography approach to predict the separation of polymer blend is demonstrated for the first time using a blend of different polyacrylates. PMID:17586517

  6. Preparation of ultrafine poly(methyl methacrylate-co-methacrylic acid) biodegradable nanoparticles loaded with ibuprofen.

    PubMed

    Saade, Hened; Diaz de León-Gómez, Ramón; Enríquez-Medrano, Francisco Javier; López, Raúl Guillermo

    2016-08-01

    Ibuprofen-loaded polymeric particles with around 9.2 nm in mean diameter, as determined by electron microscopy, dispersed in an aqueous media containing up to 12.8% solids were prepared by semicontinuous heterophase polymerization. The polymeric material is a (2/1 mol/mol) methyl methacrylate-co-methacrylic acid copolymer similar to Eudragit S100, deemed safe for human consumption and used in the manufacturing of drug-loaded pills as well as micro- and nanoparticles. The loading efficiency was 100%, attaining around 10-12% in drug content. Release studies showed that the drug is released from the nanoparticles at a slower rate than that in the case of free IB. Given their size as well as the pH values required for their dissolution, it is believed that this type of particles could be used as a basis for preparing nanosystems loaded with a variety of drugs. PMID:27126476

  7. 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. PMID:23008178

  8. Bioactive rosette nanotube-hydroxyapatite nanocomposites improve osteoblast functions.

    PubMed

    Sun, Linlin; Zhang, Lijie; Hemraz, Usha D; Fenniri, Hicham; Webster, Thomas J

    2012-09-01

    Inspired from biological systems, small synthetic organic molecules expressing the hydrogen bonding arrays of the DNA bases guanine and cytosine were prepared, and their self-assembly into rosette nanotubes (RNTs) was investigated. Due to their unique biological, physicochemical, and mechanical properties, RNTs could serve as the next generation of injectable orthopedic materials. In this study, a self-assembling module (termed twin base linkers or TBL) was synthesized, and the corresponding RNTs were used as bioactive components in composites of poly (2-hydroxyethyl methacrylate) (pHEMA) and hydroxyapatite (HA) nanoparticles (termed TBL/HA/pHEMA). The properties of these composites were characterized for solidification time, surface morphology, mechanical properties, and cytocompatibility. The experimental conditions were optimized to achieve solidification within 2-40 min, offering a range of properties for orthopedic applications. Composites with 20 wt% HA nanoparticles had a compressive strength (37.1 MPa) and an ultimate tensile stress (14.7 MPa) similar to that of a natural vertebral disc (5-30 MPa). Specifically, the TBL (0.01 mg/mL)/HA(20 wt%)/pHEMA composites improved long-term functions of osteoblasts (or bone-forming cells) in terms of collagen synthesis, alkaline phosphatase activity, and calcium deposition. Moreover, this composite inhibited fibroblast adhesion, thus decreasing the potential for undesirable fibrous tissue formation. In summary, this in vitro study provided evidence that TBL/HA/pHEMA composites are promising injectable orthopedic implant materials that warrant further mechanistic and in vivo studies. PMID:22530958

  9. 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. PMID:26900107

  10. Resin content in cement liquids of resin-modified glass ionomers.

    PubMed

    Ikeda, K; Fujishima, A; Suzuki, M; Inoue, M; Sasa, R; Miyazaki, T

    1999-09-01

    Qualitative and quantitative analyses were conducted on four kinds of resin-modified glass ionomer (RMGI) cement liquids, LC, LC II, LC III (hereinafter referred to as LCs) and VM, using HPLC and laser Raman spectroscopic methods. HPLC revealed that among the RMGI liquids LCs contain 31-32% HEMA (2-Hydroxyethyl methacrylate), and VM contains 18% of the same. The composition of RMGI cement liquids varied significantly between manufacturers. In Raman spectroscopic analyses, the spectra of liquids of various ratios of polyacrylic acid and HEMA were measured, and calculations were made on the peak intensity ratios of C=C stretch vibration to C=O stretch vibration, common in both HEMA and polyacrylic acid. The composition ratio of polycarboxylic acid to HEMA of commercial glass ionomer cements was assessed by the regression curve generated by a combination of peak intensity ratios and composition ratios. In addition, Raman spectroscopy was able to identity the differences in form of the methacryloyloxy group. PMID:10786135

  11. Fate of methyl methacrylate in rats.

    PubMed Central

    Bratt, H.; Hathway, D. E.

    1977-01-01

    Up to 88% of a single dose of methyl[14C]methacrylate in rats is expired as 14CO2 in 10 days (65% in 2 h), irrespective of the route of administration and of the specific labelling of the propylene residue of the molecule. The implications of this observation, and of the excretion of small amounts of [14C]methylmalonate, [14C]-succinate and probably of [14C]beta-hydroxyisobutyrate and 2-formylpropionate, and of the formation of [14C] normal, physiological metabolites that may be accounted for by anabolism both from 14CO2 and from [14C]acetate emergent from the citric acid cycle, are that the metabolic pathway concerned involves intermediary metabolism and relates to mitochondrial function. Present findings are discussed in relation to the imputations of a report of carcinogenic risk. PMID:889678

  12. Digital Drug Delivery: On-Off Ultrasound Controlled Antibiotic Release from Coated Matrices with Negligible Background Leaching

    PubMed Central

    Noble, Misty L.

    2014-01-01

    Hydrogels, such as crosslinked poly(2-hydroxyethyl methacrylate) (pHEMA) have been used extensively in controlled release drug delivery systems. Our previous work demonstrated an ultrasound (US)-responsive system based on pHEMA coated with a self-assembled multilayer of C12-C18 methylene chains. The resulting coating was predominantly crystalline and relatively impermeable, forming an US-activated switch that controlled drug release on-demand, and kept the drug within the matrix in the absence of US. The device, as developed did, however, show a low background drug-leaching rate independent of US irradiation. For some applications, it is desirable to have very low or zero background release rates. This was achieved here by a combination of new processing steps, and by copolymerizing HEMA with a relatively hydrophobic monomer, hydroxypropyl methacrylate (HPMA). These advances produced systems with undetectable ciprofloxacin background release rates that are capable of US-facilitated drug release – up to 14-fold increases relative to controls both before and after US exposure. In addition, these observations are consistent with the hypothesis that US-mediated disorganization of the coating allows a transient flux of water into the matrix where its interaction with bound and dissolved drug facilitates its movement both within and out of the matrix. PMID:25045519

  13. Molecularly imprinted hydrogels as functional active packaging materials.

    PubMed

    Benito-Peña, Elena; González-Vallejo, Victoria; Rico-Yuste, Alberto; Barbosa-Pereira, Letricia; Cruz, José Manuel; Bilbao, Ainhoa; Alvarez-Lorenzo, Carmen; Moreno-Bondi, María Cruz

    2016-01-01

    This paper describes the synthesis of novel molecularly imprinted hydrogels (MIHs) for the natural antioxidant ferulic acid (FA), and their application as packaging materials to prevent lipid oxidation of butter. A library of MIHs was synthesized using a synthetic surrogate of FA, 3-(4-hydroxy-3-methoxyphenyl)propionic acid (HFA), as template molecule, ethyleneglycol dimethacrylate (EDMA) as cross-linker, and 1-allylpiperazine (1-ALPP) or 2-(dimethylamino)ethyl methacrylate (DMAEMA), in combination with 2-hydroxyethyl methacrylate (HEMA) as functional monomers, at different molar concentrations. The DMAEMA/HEMA-based MIHs showed the greatest FA loading capacity, while the 1-ALLP/HEMA-based polymers exhibited the highest imprinting effect. During cold storage, FA-loaded MIHs protected butter from oxidation and led to TBARs values that were approximately half those of butter stored without protection and 25% less than those recorded for butter covered with hydrogels without FA, potentially extending the shelf life of butter. Active packaging is a new field of application for MIHs with great potential in the food industry. PMID:26213001

  14. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .../methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers (CAS... methacrylate polymers consist of basic polymers produced by the copolymerization of vinylidene chloride/methyl acrylate/methyl methacrylate such that the basic polymers or the finished food-contact articles meet...

  15. Effects of quaternary ammonium-methacrylates on the mechanical properties of unfilled resins

    PubMed Central

    Hoshika, Tomohiro; Nishitani, Yoshihiro; Yoshiyama, Masahiro; Key, William O.; William, Brantley; Agee, Kelli A.; Breschi, Lorenzo; Cadenaro, Milena; Tay, Franklin R.; Rueggeberg, Frederick; Pashley, David H.

    2014-01-01

    Objectives Adding antimicrobial/anti-MMP quaternary ammonium methacrylates (QAMs) to comonomer blends should not weaken the mechanical properties of dental resins. This work evaluated the degree conversion and mechanical properties of BisGMA/TEGDMA/HEMA (60:30:10) containing 0–15 mass% QAMs A–E (A:2-acryloxyethyltrimethyl ammonium chloride; B:[3-(methacryloylamino)propyl]trimethylammonium chloride; C:[2-(methacryloxy)ethyl] trimethyl ammonium chloride; D:diallyldimethyl ammonium chloride; E:2-(methacryloyloxy) ethyltrimethyl ammonium methyl sulfate. Methods Unfilled resins with and without QAM were placed on ATR-FTIR and light-polymerized for 20 s in a thin film t 30°C. Unfilled resin beams were casted from square hollow glass tubings. Half of the beams were tested after 3 days of drying (control); the other half were tested wet after 3 days of water storage. Results Addition of QAMs in control resins significantly increased conversion 600s after light termination, with the exception of 5% MAPTAC (p<0.05). Increase of QAM content within a formulation significantly increased conversion. Control beams gave dry Young’s moduli of ~700 MPa. Addition of 5, 10 or 15 mass% QAMs produced significant reductions in dry Young’s moduli except for 5% B or C. 15 mass% A, B and C lowered the wet Young’s moduli of the resin beams by more than 30%. The ultimate tensile stress (UTS) of control dry resin was 89±11 MPa. Addition of 5–10 mass% QAMs had no adverse effect on the dry UTS. After water storage, the UTS of all resin blends fell significantly (p<0.05), especially when 15 wt% QAMs was added. Control dry beams gave fracture toughness (KIC) values of 0.88±0.1 MPa√m. Wet values were significantly higher at 1.02±0.06 (p<0.05). KIC of dry beams varied from 0.85±0.08 at 5% QAMs to 0.49±0.05 at 15% QAMs. Wet beams gave KIC values of 1.02±0.06 MPa√m that fell to 0.23±0.01 at 15% QAMs. Significance Addition of 10% QAMs increased the degree of conversion of

  16. HEALTH AND ENVIRONMENTAL EFFECTS PROFILE FOR METHYL METHACRYLATE

    EPA Science Inventory

    The Health and Environmental Effects Profile for methyl methacrylate was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardo...

  17. 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. PMID:27040248

  18. 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.

  19. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    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. PMID:27609095

  20. GENOTOXICITY OF ACRYLIC ACID, METHYL ACRYLATE, ETHYL ACRYLATE, METHYL METHACRYLATE, AND ETHYL METHACRYLATE IN L5178Y MOUSE LYMPHOMA CELLS (JOURNAL VERSION)

    EPA Science Inventory

    A series of monomeric acrylate/methacrylate esters (methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate) as well as acrylic acid were examined for genotoxic activity in L5178Y mouse lymphoma cells without exogenous activation. All five compounds induced c...

  1. 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. PMID:19463569

  2. Synthesis, Thermal Properties, and Thermoresponsive Behaviors of Cyclic Poly(2-(dimethylamino)ethyl Methacrylate)s.

    PubMed

    An, Xiaonan; Tang, Qingquan; Zhu, Wen; Zhang, Ke; Zhao, Youliang

    2016-06-01

    This study aims at physicochemical properties of thermo- and pH/CO2 -responsive cyclic homopolymers. Three examples of cyclic poly(2-(dimethylamino)ethyl methacrylate)s (PDMAs) are synthesized by combining the reversible addition-fragmentation chain transfer process and the Diels-Alder ring-closure reaction. After cyclization, the glass transition temperature significantly increases (ΔTg = 51.8-59.7 °C) due to the different configurational entropy and end groups, and the maximum decomposition temperature to lose the pendent groups is drastically decreased from 309 to 278 °C. Effects of polymerization degree, polymer concentration, additive of NaCl, and pH/CO2 on lower critical solution temperature behaviors of PDMA aqueous solutions are investigated. The cloud points (Tc ) of ring PDMAs are usually higher than their linear precursors, and the ΔTc values obtained under a fixed condition can reach up to 20.7 °C, revealing the crucial role of the topology effect. This study paves the way for unique properties and applications of smart cyclic polymers and their derivatives. PMID:27126247

  3. A small molecule focal adhesion kinase (FAK) inhibitor, targeting Y397 site: 1-(2-hydroxyethyl)-3, 5, 7-triaza-1-azoniatricyclo [3.3.1.1(3,7)]decane; bromide effectively inhibits FAK autophosphorylation activity and decreases cancer cell viability, clonogenicity and tumor growth in vivo.

    PubMed

    Golubovskaya, Vita M; Figel, Sheila; Ho, Baotran T; Johnson, Christopher P; Yemma, Michael; Huang, Grace; Zheng, Min; Nyberg, Carl; Magis, Andrew; Ostrov, David A; Gelman, Irwin H; Cance, William G

    2012-05-01

    Focal adhesion kinase (FAK) is a protein tyrosine kinase that is overexpressed in most solid types of tumors and plays an important role in the survival signaling. Recently, we have developed a novel computer modeling combined with a functional assay approach to target the main autophosphorylation site of FAK (Y397). Using these approaches, we identified 1-(2-hydroxyethyl)-3, 5, 7-triaza-1-azoniatricyclo [3.3.1.1(3,7)]decane; bromide, called Y11, a small molecule inhibitor targeting Y397 site of FAK. Y11 significantly and specifically decreased FAK autophosphorylation, directly bound to the N-terminal domain of FAK. In addition, Y11 decreased Y397-FAK autophosphorylation, inhibited viability and clonogenicity of colon SW620 and breast BT474 cancer cells and increased detachment and apoptosis in vitro. Moreover, Y11 significantly decreased tumor growth in the colon cancer cell mouse xenograft model. Finally, tumors from the Y11-treated mice demonstrated decreased Y397-FAK autophosphorylation and activation of poly (ADP ribose) polymerase and caspase-3. Thus, targeting the major autophosphorylation site of FAK with Y11 inhibitor is critical for development of cancer therapeutics and carcinogenesis field. PMID:22402131

  4. Antifouling foldable acrylic IOLs loaded with norfloxacin by aqueous soaking and by supercritical carbon dioxide technology.

    PubMed

    González-Chomón, Clara; Braga, Mara E M; de Sousa, Herminio C; Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2012-10-01

    Cataracts treatment usually involves the extraction of the opaque crystalline lens and its replacement by an intraocular lens (IOL). A serious complication is the occurrence of endophthalmitis, a post-surgery infection mainly caused by Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. IOLs having the ability to load and to release norfloxacin in a controlled way and at efficient therapeutic levels may help to overcome these issues. In this work, acrylic hydrogels combining 2-hydroxyethyl methacrylate (HEMA) and 2-butoxyethyl methacrylate (BEM) at various ratios were prepared to attain biocompatible networks that can be foldable even in the dry state and thus insertable through minor ocular incision, and that load therapeutic amounts of norfloxacin. Acrylamide (AAm) and methacrylic acid (MAAc) were also incorporated as functional comonomers in small proportions. Water sorption, contact angle, protein adsorption, and optical properties of the networks were characterized. BEM notably decreased the T(g) of the networks, but also the loading by immersion in aqueous solution (presoaking). Then, a scCO(2)-based impregnation/deposition (SSI) method was implemented to improve the uptake of the drug. Loading capacities were discussed in terms of the comonomers composition and the employed method and operational conditions. The networks prepared with HEMA/BEM 20:80 vol/vol and processed with supercritical fluids combine adequate mechanical properties, biocompatibility and norfloxacin loading/release, and seem to be suitable for developing norfloxacin-eluting IOLs. PMID:22846620

  5. 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.

  6. 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. PMID:24114322

  7. 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

  8. 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). PMID:24607180

  9. 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.

  10. A novel adsorbent for protein chromatography: supermacroporous monolithic cryogel embedded with Cu2+-attached sporopollenin particles.

    PubMed

    Erzengin, Mahmut; Ünlü, Nuri; Odabaşı, Mehmet

    2011-01-21

    The aim of this study is to prepare supermacroporous cryogels embedded with Cu(2+)-attached sporopollenin particles (Cu(2+)-ASP) having large surface area for high protein adsorption capacity. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic cryogel column embedded with Cu(2+)-ASP was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N'-methylene-bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for affinity purification of human serum albumin (HSA). Firstly, Cu(2+) ions were attached to sporopollenin particles (SP), then the supermacroporous PHEMA cryogel with embedded Cu(2+)-ASP was produced by free radical polymerization using N,N,N',N'-tetramethylene diamine (TEMED) and ammonium persulfate (APS) as initiator/activator pair in an ice bath. Embedded particles (10 mg) in PHEMA-based cryogel column were used in the adsorption/desorption of HSA from aqueous solutions. Optimum conditions of adsorption experiments were performed at pH 8.0 phosphate buffer, with flow rate of 0.5 mL/min, and at 5°C. The maximum amount of HSA adsorption from aqueous solution was very high (677.4 mg/g SP) with initial concentration 6 mg/mL. It was observed that HSA could be repeatedly adsorbed and desorbed to the embedded Cu(2+)-ASP in PHEMA cryogel without significant loss of adsorption capacity. PMID:21176840

  11. Novel adsorbent for DNA adsorption: Fe(3+)-attached sporopollenin particles embedded composite cryogels.

    PubMed

    Ceylan, Şeyda; Odabaşı, Mehmet

    2013-12-01

    The aim of this study is to prepare supermacroporous cryogels embedded with Fe(3+)-attached sporopollenin particles (Fe(3++)-ASPs) having large surface area for high DNA adsorption capacity. Supermacroporous poly(2-hydroxyethyl methacrylate) (PHEMA)-based monolithic cryogel column embedded with Fe3+(+)-ASPs was prepared by radical cryo-copolymerization of 2-hydroxyethyl methacrylate (HEMA) with N,N´-methylene- bis-acrylamide (MBAAm) as cross-linker directly in a plastic syringe for DNA adsorption studies. Firstly, Fe3+(+) ions were attached to the sporopollenin particles (SPs), then the supermacroporous PHEMA cryogel with embedded Fe(3++)-ASPs was produced by free radical polymerization using N,N,N´, N´-Tetramethylethylenediamine (TEMED) and ammonium persulfate (APS) as initiator/activator pair in an ice bath. Optimum conditions of adsorption experiments were performed at pH 6.0 (0.02 M Tris buffer containing 0.2 M NaCl), with flow rate of 0.5 mL/min, and at 5°C. The maximum amount of DNA adsorption from aqueous solution was very high (109 mg/g SPs) with initial concentration of 3 mg/mL. It was observed that DNA could be repeatedly adsorbed and desorbed with this composite cryogel without significant loss of adsorption capacity. As a result, higher amounts of DNA adsorbed these composite cryogels are expected to be good candidate for achieving higher removal of anti-DNA antibodies from systemic lupus erythematosus (SLE) patients plasma. PMID:23305206

  12. Real time in vitro studies of doxorubicin release from PHEMA nanoparticles

    PubMed Central

    Chouhan, Raje; Bajpai, AK

    2009-01-01

    Background Many anticancer agents have poor water solubility and therefore the development of novel delivery systems for such molecules has received significant attention. Nanocarriers show great potential in delivering therapeutic agents into the targeted organs or cells and have recently emerged as a promising approach to cancer treatments. The aim of this study was to prepare and use poly-2-hydroxyethyl methacrylate (PHEMA) nanoparticles for the controlled release of the anticancer drug doxorubicin. Results PHEMA nanoparticles have been synthesized and characterized using FTIR and scanning electron microscopy (SEM), particle size analysis and surface charge measurements. We also studied the effects of various parameters such as percent loading of drugs, chemical architecture of the nanocarriers, pH, temperature and nature of the release media on the release profiles of the drug. The chemical stability of doxorubicin in PBS was assessed at a range of pH. Conclusion Suspension polymerization of 2-hydroxyethyl methacrylate (HEMA) results in the formation of swellable nanoparticles of defined composition. PHEMA nanoparticles can potentially be used for the controlled release of the anticancer drug doxorubicin. PMID:19843333

  13. 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... methacrylate copolymer with hydroxymethyl acrylamide, vinyl chloride and long chain fatty alkyl acrylate (PMN P... Substances § 721.10523 Perfluoroalkylethyl methacrylate copolymer with hydroxymethyl acrylamide,...

  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... methacrylate copolymer with hydroxymethyl acrylamide, vinyl chloride and long chain fatty alkyl acrylate (PMN P... Substances § 721.10523 Perfluoroalkylethyl methacrylate copolymer with hydroxymethyl acrylamide,...

  15. 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

  16. 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,...

  17. 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,...

  18. 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 reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  19. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers (CAS Reg. No. 34364-83-5) identified in paragraph (a) of this section may be.../methyl acrylate/methyl methacrylate polymers consist of basic polymers produced by the...

  20. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers (CAS Reg. No. 34364-83-5) identified in paragraph (a) of this section may be.../methyl acrylate/methyl methacrylate polymers consist of basic polymers produced by the...

  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 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Poly(hydroxyethyl methacrylate)-dye copolymers. 73...(hydroxyethyl methacrylate)-dye copolymers. (a) Identity. The color additives are formed by reacting one or more of the reactive dyes listed in this paragraph with poly(hydroxyethyl methacrylate), so that...

  3. 21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Poly(hydroxyethyl methacrylate)-dye copolymers. 73...(hydroxyethyl methacrylate)-dye copolymers. (a) Identity. The color additives are formed by reacting one or more of the reactive dyes listed in this paragraph with poly(hydroxyethyl methacrylate), so that...

  4. 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 reacting the dyes, either alone or in combination, with a vinyl alcohol/methyl methacrylate copolymer,...

  5. N-(2-hydroxyethyl)-N,2-dimethyl-8-{[(4R)-5-methyl-3,4-dihydro-2H-chromen-4-yl]amino}imidazo[1,2-a]pyridine-6-carboxamide (PF-03716556), a novel, potent, and selective acid pump antagonist for the treatment of gastroesophageal reflux disease.

    PubMed

    Mori, Hiroki; Tonai-Kachi, Hiroko; Ochi, Yasuo; Taniguchi, Yasuhito; Ohshiro, Hiroyuki; Takahashi, Nobuyuki; Aihara, Takeshi; Hirao, Akiko; Kato, Teruhisa; Sakakibara, Minoru; Kurebayashi, Yoichi

    2009-02-01

    Inhibition of H(+),K(+)-ATPase is accepted as the most effective way of controlling gastric acid secretion. However, current acid suppressant therapy for gastroesophageal reflux disease, using histamine H(2) receptor antagonists and proton pump inhibitors, does not fully meet the needs of all patients because of their mechanism of action. This study sought to characterize the in vitro and in vivo pharmacology of a novel acid pump antagonist, N-(2-Hydroxyethyl)-N,2-dimethyl-8-{[(4R)-5-methyl-3,4-dihydro-2H-chromen-4-yl]amino}imidazo[1,2-a]pyridine-6-carboxamide (PF-03716556), and to compare it with other acid suppressants. Porcine, canine, and human recombinant gastric H(+),K(+)-ATPase activities were measured by ion-leaky and ion-tight assay. The affinities for a range of receptors, ion channels, and enzymes were determined to analyze selectivity profile. Acid secretion in Ghosh-Schild rats and Heidenhain pouch dogs were measured by titrating perfusate and gastric juice samples. PF-03716556 demonstrated 3-fold greater inhibitory activity than 5,6-dimethyl-2-(4-fluorophenylamino)-4-(1-methyl-1,2,3,4-tetrahydroisoquinoline-2-yl)pyrimidine (revaprazan), the only acid pump antagonist that has been available on the market, in ion-tight assay. The compound did not display any species differences, exhibiting highly selective profile including the canine kidney Na(+),K(+)-ATPase. Kinetics experiments revealed that PF-03716556 has a competitive and reversible mode of action. More rapid onset of action than 5-methoxy-2-{[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]-sulfinyl}-benzimidazole (omeprazole) and 3-fold greater potency than revaprazan were observed in Ghosh-Schild rats and Heidenhain pouch dogs. PF-03716556, a novel acid pump antagonist, could improve upon or even replace current pharmacological treatment for gastroesophageal reflux disease. PMID:18981288

  6. 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. PMID:26902925

  7. Rapid and selective removal of preservative from ophthalmic formulations during eyedrops instillation.

    PubMed

    Hsu, Kuan-Hui; Chauhan, Anuj

    2015-11-01

    About 70% of eyedrops contain benzalkonium chloride (BAK) as a preservative to prevent the growth of microorganisms. While preservatives are mandated to maintain sterility, many patients exhibit irritation and toxicity to such compounds. We propose to mitigate the ocular toxicity in the ocular formulations without compromising sterility by designing a device that can be incorporated into an eyedrops bottle to selectively remove the preservatives during the process of drop instillation. Here, we specifically focus on macroporous poly(2-hydroxyethyl methacrylate) (pHEMA) gel due to its excellent biocompatibility and high partition coefficient for BAK. In addition to specific selectivity for BAK, the device also requires high hydraulic permeability to allow drop dispensing without excessive pressure drop. The pHEMA monolith can remove nearly 100% of contained BAK from a 25 ml, 0.012% BAK solution with negligible uptake of the hydrophilic drugs such as timolol and dorzolamide. The filter, however, had to be pre-equilibrated with hydrophobic drugs to reach a high separation of BAK without reducing the concentration of the active drug. The average hydraulic permeability of the filter was 0.025 Darcy, which is about 5-fold lower than the ideal value. Incorporation of a pHEMA macroporous gel into an eyedrops bottle can virtually eliminate the exposure of the eyes to the preservatives without compromising the sterility. Our novel design can eliminate the preservative induced toxicity from eyedrops thereby impacting hundreds of millions of patients with chronic ophthalmic diseases such as glaucoma and dry eyes. PMID:26459089

  8. 3D chemical characterization of frozen hydrated hydrogels using ToF-SIMS with argon cluster sputter depth profiling.

    PubMed

    Taylor, Michael; Scurr, David; Lutolf, Matthias; Buttery, Lee; Zelzer, Mischa; Alexander, Morgan

    2016-06-01

    Hydrogels have been used extensively in bioengineering as artificial cell culture supports. Investigation of the interrelationship between cellular response to the hydrogel and its chemistry ideally requires methods that allow characterization without labels and can map species in three-dimensional to follow biomolecules adsorbed to, and absorbed into, the open structure before and during culture. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has the potential to be utilized for through thickness characterization of hydrogels. The authors have established a simple sample preparation procedure to successfully achieve analysis of frozen hydrated hydrogels using ToF-SIMS without the need for dry glove box entry equipment. They demonstrate this on a poly(2-hydroxyethyl methacrylate) (pHEMA) film where a model protein (lysozyme) is incorporated using two methods to demonstrate how protein distribution can be determined. A comparison of lysozyme incorporation is made between the situation where the protein is present in a polymer dip coating solution and where lysozyme is in an aqueous medium in which the film is incubated. It is shown that protonated water clusters H(H2O)n (+) where n = 5-11 that are indicative of ice are detected through the entire thickness of the pHEMA. The lysozyme distribution through the pHEMA hydrogel films can be determined using the intensity of a characteristic amino acid secondary ion fragment. PMID:26253107

  9. 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.

  10. 40 CFR 721.10619 - Perfluoroalkylethyl methacrylate copolymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... as perfluoroalkylethyl methacrylate copolymer (PMN P-11-653) is subject to reporting under this.... Requirements as specified in § 721.80(p)(any amount after September 30, 2014). (b) Specific requirements. The...) Recordkeeping. Recordkeeping requirements as specified in § 721.125 (a), (b), (c), (f), (h), and (i)...

  11. 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.

  12. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775 Section 172.775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD...

  13. 21 CFR 177.1830 - Styrene-methyl methacrylate copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Styrene-methyl methacrylate copolymers. 177.1830 Section 177.1830 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and...

  14. Alcohol vapor sensory properties of nanostructured conjugated polymers

    NASA Astrophysics Data System (ADS)

    Bearzotti, Andrea; Macagnano, Antonella; Pantalei, Simone; Zampetti, Emiliano; Venditti, Iole; Fratoddi, Ilaria; Vittoria Russo, Maria

    2008-11-01

    The response to relative humidity (RH) and alcohol vapors of resistive-type sensors based on nanobeads of conjugated polymers, namely polyphenylacetylene (PPA) and copolymer poly[phenylacetylene-(co-2-hydroxyethyl methacrylate)] (P(PA/HEMA)), were investigated. Sensors based on ordered arrays of these nanostructured polymeric materials showed stable and reproducible current intensity variations in the range 10-90% of relative humidity at room temperature. Both polymers also showed sensitivity to aliphatic chain primary alcohols, and a fine tuning of the sensor response was obtained by varying the chain length of the alcohol in relation to the polarity. The nanostructured feature of polymeric-based membranes seems to have an effect on the sensing response and an enhancement of the sensitivity was observed for the response to water and alcohol vapor variations with respect to previous studies based on amorphous polyphenylacetylene. High stability of the polymeric nanostructured membranes was detected with no aging after two weeks in continuum stressing measurement conditions.

  15. 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. PMID:25561048

  16. 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. PMID:23587005

  17. 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+.

  18. A molecular imprinted SPR biosensor for sensitive determination of citrinin in red yeast rice.

    PubMed

    Atar, Necip; Eren, Tanju; Yola, Mehmet Lütfi

    2015-10-01

    A novel and sensitive molecular imprinted surface plasmon resonance (SPR) biosensor was developed for selective determination of citrinin (CIT) in red yeast rice. Firstly, the gold surface of SPR chip was modified with allyl mercaptane. Then, CIT-imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoglutamic acid) (p(HEMA-MAGA)) film was generated on the gold surface modified with allyl mercaptane. The unmodified and imprinted surfaces were characterized by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and contact angle measurements. The linearity range and the detection limit were obtained as 0.005-1.0 ng/mL and 0.0017 ng/mL, respectively. The SPR biosensor was applied to determination of CIT in red yeast rice sample. PMID:25872420

  19. 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.

  20. Fast in vitro hydrolytic degradation of polyester urethane acrylate biomaterials: structure elucidation, separation and quantification of degradation products.

    PubMed

    Ghaffar, A; Verschuren, P G; Geenevasen, J A J; Handels, T; Berard, J; Plum, B; Dias, A A; Schoenmakers, P J; van der Wal, Sj

    2011-01-21

    Synthetic biomaterials have evoked extensive interest for applications in the field of health care. Prior to administration to the body a quantitative study is necessary to evaluate their composition. An in vitro method was developed for the quick hydrolytic degradation of poly-2-hydroxyethyl methacrylate (pHEMA), poly(lactide-co-glycolide50/50)1550-diol (PLGA(50:50)(1550)-diol), PLGA(50:50)(1550)-diol(HEMA)(2) and PLGA(50:50)(1550)-diol(etLDI-HEMA)(2) containing ethyl ester lysine diisocyanate (etLDI) linkers using a microwave instrument. Hydrolysis time and temperature were optimized while monitoring the degree of hydrolysis by (1)H NMR spectroscopy. Complete hydrolytic degradation was achieved at 120°C and 3 bar pressure after 24 h. Chemical structure elucidations of the degradation products were carried out using (1)H and (13)C NMR spectroscopy. The molecular weight (MW) of the polymethacrylic backbone was estimated via size-exclusion chromatography coupled to refractive index detection (SEC-dRI). A bimodal MW distribution was found experimentally, also in the pHEMA starting material. The number average molecular weights (M(n)) of the PLGA-links (PLGA(50:50)(1550)-diol) were calculated by high pressure liquid chromatography-time-of-flight mass spectrometry (HPLC-TOF-MS) and (1)H NMR. The amounts of the high and low MW degradation products were determined by SEC-dRI and, HPLC-TOF-MS, respectively. The main hydrolysis products poly (methacrylic acid) (PMAA), ethylene glycol (EG), diethylene glycol (DEG), lactic acid (LA), glycolic acid (GA) and lysine were recovered almost quantitatively. The current method leads to the complete hydrolytic degradation of these materials and will be helpful to study the degradation behavior of these novel cross-linked polymeric biomaterials. PMID:21167489

  1. Hydration and chain entanglement determines the optimum thickness of poly(HEMA-co-PEG₁₀MA) brushes for effective resistance to settlement and adhesion of marine fouling organisms.

    PubMed

    Yandi, Wetra; Mieszkin, Sophie; Martin-Tanchereau, Pierre; Callow, Maureen E; Callow, James A; Tyson, Lyndsey; Liedberg, Bo; Ederth, Thomas

    2014-07-23

    Understanding how surface physicochemical properties influence the settlement and adhesion of marine fouling organisms is important for the development of effective and environmentally benign marine antifouling coatings. We demonstrate that the thickness of random poly(HEMA-co-PEG10MA) copolymer brushes affect antifouling behavior. Films of thicknesses ranging from 50 to 1000 Å were prepared via surface-initiated atom-transfer radical polymerization and characterized using infrared spectroscopy, ellipsometry, atomic force microscopy and contact angle measurements. The fouling resistance of these films was investigated by protein adsorption, attachment of the marine bacterium Cobetia marina, settlement and strength of attachment tests of zoospores of the marine alga Ulva linza and static immersion field tests. These assays show that the polymer film thickness influenced the antifouling performance, in that there is an optimum thickness range, 200-400 Å (dry thickness), where fouling of all types, as well as algal spore adhesion, was lower. Field test results also showed lower fouling within the same thickness range after 2 weeks of immersion. Studies by quartz crystal microbalance with dissipation and underwater captive bubble contact angle measurements show a strong correlation between lower fouling and higher hydration, viscosity and surface energy of the poly(HEMA-co-PEG10MA) brushes at thicknesses around 200-400 Å. We hypothesize that the reduced antifouling performance is caused by a lower hydration capacity of the polymer for thinner films, and that entanglement and crowding in the film reduces the conformational freedom, hydration capacity and fouling resistance for thicker films. PMID:24945705

  2. A novel crosslinker for UV copolymerization of N-vinyl pyrrolidone and methacrylates

    SciTech Connect

    Lai, Yu-Chin

    1993-12-31

    Methacryloxyethyl vinyl carbonate, a novel crosslinker containing a vinyl carbonate and a methacrylate group which is capable of copolymerizing N-vinyl pyrrolidone and methacrylates, was prepared. With this crosslinker, N-vinyl pyrrolidone and methacrylates can copolymerize efficiently under strictly UV condition. Previously, polymeric systems containing N-vinyl pyrrolidone and methacrylates were prepared using thermal initiators, or a combination of thermal and UV initiators in the presence of crosslinkers such as allyl methacrylate or ethylene glycol dimethacrylate, These processes often led to polymers with inferior properties and less controllable quality. The use of this novel crosslinker represents a sharp improvement in polymerization conditions (UV vs heat) as well as product quality.

  3. Aminated poly(glycidyl methacrylate)s for constructing efficient gene carriers.

    PubMed

    Dou, X B; Chai, M Y; Zhu, Y; Yang, W T; Xu, F J

    2013-04-24

    Aminated poly(glycidyl methacrylate) (PGMA) vectors could efficiently mediate gene delivery. Recently, we reported that ethanolamine (EA)-functionalized PGMA could provide high transfection efficiency, while exhibiting very low toxicity. Herein, different amine species, including 1-amino-2-propanol (AP1), 3-amino-2-propanol (AP2), EA, and N,N,-dimethylethylenediamine (DED), and its quaternized DED, were proposed to aminate PGMA. The DNA condensation abilities, pH buffering capacities, cytotoxicities, and gene transfection efficiencies of the resultant aminated PGMA vectors were systematically compared. Compared with EA, AP1 (or AP2) contains an additional methyl (or methylene) group. EA-, AP1-, and AP2-functionalized PGMA vectors exhibited similar condensation abilities. The methyl (from AP1) and methylene (from AP2) species could benefit the gene delivery. The transfection performance mediated by AP1-functionalized PGMA is best. DED possesses a tertiary amine group, which could be quaternized to further enhance the DNA condensation ability of aminated PGMA. No obvious increase in cytotoxicity of quaternized DED-aminated PGMA was observed. But both DED- and its quaternized counterpart-functionalized PGMA vectors exhibited very low pH buffering capacities, making them exhibit poor gene transfection performances. The current study would provide useful information for constructing better PGMA-based delivery systems with good biophysical properties. PMID:23514579

  4. A novel capsular tension ring as local sustained-release carrier for preventing posterior capsule opacification.

    PubMed

    Lei, Ming; Peng, Zihang; Dong, Qian; He, Yuanfeng; Zhang, Zhaoguo; Zhang, Xuefei; Yan, Mina; Zhao, Chunshun

    2016-05-01

    One of the most important and challenging goals in pharmaceutical prevention for posterior capsule opacification is to preserve an effective drug concentration in capsular bag for a long period without affecting the patients' vision. Here, a novel kind of composite, which was prepared by 2-hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) via a two-step process, was applied for capsular tension ring (CTR) as an implant that could deliver docetaxel (DTX) over a long period of time. The drug release rate of the composite could be controlled by the ethyleneglycol dimethacrylate (EGDMA) content and the ratio of HEMA/MMA as well as the structure of porous PMMA framework. The CTR could continuously release DTX for up to 6 weeks in vitro and maintain DTX in effective concentration in the aqueous humor after 42 days. Docetaxel-load capsular tension ring (DTX-CTR) presented strong inhibition on the lens epithelial cells in-vivo without obvious damage to normal tissues. These results indicate that the drug sustained-release CTR can provide a promising application in posterior capsule opacification prevention. PMID:26970509

  5. Experimental and numerical measurements of adhesion energies between PHEMA and PGLYMA with hydroxyapatite crystal.

    PubMed

    Youssefian, Sina; Liu, Pingsheng; Askarinejad, Sina; Shalchy, Faezeh; Song, Jie; Rahbar, Nima

    2015-08-01

    Synthetic orthopaedic materials consisting of a single bioinert polymeric material do not meet the complex biological and physical requirements of scaffold-guided bone tissue repair and regeneration. Of particular interest is the design of biocompatible hydrogel-hydroxyapatite composite bone substitutes with outstanding interfacial adhesion that would warranty the ability for the composite to withstand functional loadings without exhibiting brittle fractures during the dynamic guided tissue regeneration. For this purpose, the hydroxylated side chain of chemically cross-linked poly (2-hydroxyethyl methacrylate) (pHEMA) is substitute with a carboxylated side chain to make poly (glycerol methacrylate) (pGLYMA). Here, we carry out atomistic simulations and atomic force microscopy to predict and experimentally determine the interfacial adhesion energies of pHEMA and pGLYMA with the surface of single-crystalline hydroxyapatite (HA) whiskers. Both experimental and numerical results showed that pGLYMA has stronger adhesion forces with HA and may be used for preparing a high-affinity polymer-HA composite. The high adhesive interactions between pGLYMA and HA were found to be due to strong electrostatic energies. PMID:26179911

  6. Enzyme-catalyzed hydrolysis of dentin adhesives containing a new urethane-based trimethacrylate monomer

    PubMed Central

    Park, Jong-Gu; Ye, Qiang; Topp, Elizabeth M.; Spencer, Paulette

    2009-01-01

    A new trimethacrylate monomer with urethane-linked groups, 1,1,1-tri-[4-(methacryloxyethylamino-carbonyloxy)-phenyl]ethane (MPE), was synthesized, characterized, and used as a co-monomer in dentin adhesives. Dentin adhesives containing 2-hydroxyethyl methacrylate (HEMA, 45% w/w) and 2,2-bis[4(2-hydroxy-3-methacryloyloxy-propyloxy)-phenyl] propane (BisGMA, 30% w/w) in addition to MPE (25% w/w) were formulated with H2O at 0 (MPE0), 8 (MPE8) and 16 wt % water (MPE16) to simulate the wet demineralized dentin matrix and compared with controls [HEMA/BisGMA, 45/55 w/w, at 0 (C0), 8 (C8) and 16 wt% water (C16)]. The new adhesive showed a degree of double bond conversion and mechanical properties comparable with control, with good penetration into the dentin surface and a uniform adhesive/dentin interface. On exposure to porcine liver esterase, the net cumulative methacrylic acid (MAA) release from the new adhesives was dramatically (P < 0.05) decreased relative to the control, suggesting that the new monomer improves esterase resistance. PMID:19582843

  7. Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

    PubMed Central

    Seo, Ji-Hun; Nakagawa, Shino; Hirata, Koichiro

    2014-01-01

    Summary 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. PMID:25550723

  8. PolyAdenine cryogels for fast and effective RNA purification.

    PubMed

    Köse, Kazım; Erol, Kadir; Özgür, Erdoğan; Uzun, Lokman; Denizli, Adil

    2016-10-01

    Cryogels are used effectively for many diverse applications in a variety of fields. The isolation or purification of RNA, one of the potential utilizations for cryogels, is crucial due to their vital roles such as encoding, decoding, transcription and translation, and gene expression. RNA principally exists within every living thing, but their tendency to denaturation easily is still the most challenging issue. Herein, we aimed to develop adenine incorporated polymeric cryogels as an alternative sorbent for cost-friendly and fast RNA purification with high capacity. For this goal, we synthesized the polymerizable derivative of adenine called as adenine methacrylate (AdeM) through the substitution reaction between adenine and methacryloyl chloride. Then, 2-hydroxyethyl methacrylate (HEMA)-based cryogels were prepared in a partially frozen aqueous medium by copolymerization of monomers, AdeM, and HEMA. The cryogels were characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), surface area measurements, thermogravimetric analysis (TGA), and swelling tests. RNA adsorption experiments were performed via batch system while varying different conditions including pH, initial RNA concentration, temperature, and interaction time. We achieved high RNA adsorption capacity of cryogels, with the swelling ratio around 510%, as 11.86mg/g. The cryogels might be reused at least five times without significant decrease in adsorption capacity. PMID:27434154

  9. Hydrogel nanocomposites: a potential UV/blue light filtering material for ophthalmic lenses.

    PubMed

    Bozukova, Dimitriya; Pagnoulle, Christophe; De Pauw-Gillet, Marie-Claire; Vertruyen, Bénédicte; Jérôme, Robert; Jérôme, Christine

    2011-01-01

    Poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (poly(HEMA-co-MMA)) and ZnS hydrogel nanocomposites were prepared and characterized. The chemical composition of the inorganic nanoparticles was confirmed by X-ray diffraction, and the homogeneity of their distribution within the hydrogel was assessed by transmission electron microscopy. The influence of the content of ZnS nanoparticles on the optical performances of the nanocomposites was investigated by UV-Vis spectroscopy. The ability of the hydrogel nanocomposites to filter the hazardous UV light and part of the blue light was reported, which makes them valuable candidates for ophthalmic lens application. In contrast to the optical properties, the thermo-mechanical properties of neat poly(HEMA-co-MMA) hydrogels were found to be largely independent of filling by ZnS nanoparticles (≤2 mg/ml co-monomer mixture). Finally, in vitro cell adhesion test with lens epithelial cells (LECs), extracted from porcine lens crystalline capsule, showed that ZnS had no deleterious effect on the biocompatibility of neat hydrogels, at least at low content. PMID:20961497

  10. Postmodification of PS-b-P4VP diblock copolymer membranes by ARGET ATRP.

    PubMed

    Keskin, Damla; Clodt, Juliana I; Hahn, Janina; Abetz, Volker; Filiz, Volkan

    2014-07-29

    The surfaces of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer membranes were modified in order to obtain polymer brushes by using surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Isoporous membranes were prepared by the combination of self-assembly of PS-b-P4VP diblock copolymers and the nonsolvent induced phase separation process, also known as "phase inversion". In order to allow further functionalization, the membranes were modified with an ATRP initiator, 2-bromoisobutyryl bromide (BIBB). Therefore, the mussel-inspired poly(dopamine) coating was used to attach BIBB on the membranes surface. In the next step the coated membranes were postmodified by using surface-initiated ARGET ATRP with the hydrophilic monomer 2-hydroxyethyl methacrylate (HEMA). HEMA as a hydrophilic methacrylate was chosen for the modification in order to enhance the membrane characteristics and to obtain a surface with antifouling properties. The surface-initiated ARGET ATRP reaction was carried out using different reaction times and environments. PHEMA could successfully incorporate on the membrane surface as confirmed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), (1)H nuclear magnetic resonance spectroscopy ((1)H NMR), scanning electron microscopy (SEM), and contact angle measurements. Furthermore, stability tests against heat and solvents were performed, and water flux was measured for the raw and modified membranes. Stability against heat and hydrophilicity could be increased with this type of modification for diblock copolymer membranes. PMID:24948370

  11. Determination of Ammonium Ion Using a Reagentless Amperometric Biosensor Based on Immobilized Alanine Dehydrogenase

    PubMed Central

    Tan, Ling Ling; Musa, Ahmad; Lee, Yook Heng

    2011-01-01

    The use of the enzyme alanine dehydrogenase (AlaDH) for the determination of ammonium ion (NH4+) usually requires the addition of pyruvate substrate and reduced nicotinamide adenine dinucleotide (NADH) simultaneously to effect the reaction. This addition of reagents is inconvenient when an enzyme biosensor based on AlaDH is used. To resolve the problem, a novel reagentless amperometric biosensor using a stacked methacrylic membrane system coated onto a screen-printed carbon paste electrode (SPE) for NH4+ ion determination is described. A mixture of pyruvate and NADH was immobilized in low molecular weight poly(2-hydroxyethyl methacrylate) (pHEMA) membrane, which was then deposited over a photocured pHEMA membrane (photoHEMA) containing alanine dehydrogenase (AlaDH) enzyme. Due to the enzymatic reaction of AlaDH and the pyruvate substrate, NH4+ was consumed in the process and thus the signal from the electrocatalytic oxidation of NADH at an applied potential of +0.55 V was proportional to the NH4+ ion concentration under optimal conditions. The stacked methacrylate membranes responded rapidly and linearly to changes in NH4+ ion concentrations between 10–100 mM, with a detection limit of 0.18 mM NH4+ ion. The reproducibility of the amperometrical NH4+ biosensor yielded low relative standard deviations between 1.4–4.9%. The stacked membrane biosensor has been successfully applied to the determination of NH4+ ion in spiked river water samples without pretreatment. A good correlation was found between the analytical results for NH4+ obtained from the biosensor and the Nessler spectrophotometric method. PMID:22163699

  12. Tailoring the degradation rates of thermally responsive hydrogels designed for soft tissue injection by varying the autocatalytic potential

    PubMed Central

    Zhu, Yang; Jiang, Hongbin; Ye, Sang-Ho; Yoshizumi, Tomo; Wagner, William R.

    2015-01-01

    The ability to modulate the degradation properties of biomaterials such as thermally responsive hydrogels is desirable when exploring new therapeutic strategies that rely on the temporary presence of a placed scaffold or gel. Here we report a method of manipulating the absorption rate of a poly(N-isopropylacrylamide) ((poly(NIPAAm)) based hydrogel across a wide range (from 1 d to 5 mo) by small alterations in the composition. Relying upon the autocatalytic effect, the degradation of poly(NIPAAm-co-HEMA-co-MAPLA), (HEMA=2-hydroxyethyl methacrylate; MAPLA=methacrylate-polylactide) was greatly accelerated by adding a fourth monomer methacrylic acid (MAA) at no more than 2 mol% to obtain poly(NIPAAm-co-HEMA-co-MAPLA-co-MAA) (pNHMMj) where j reflects the MAA molar % in the reactant mixture. MAA residue introduction decreased the pH inside the hydrogels and in surrounding buffered solutions. Accelerated degradation positively correlated with MAA content in pNHMMj polymers, putatively by the accelerated cleavage of MAPLA residues to raise the transition temperature of the polymer above body temperature. Physical properties including thermal transition behavior and initial mechanical strength did not vary significantly with MAA content. A rat hindlimb injection model generally reflected the in vitro observation that higher MAA content resulted in more rapid degradation and cellular infiltration. The strategy of tuning the degradation of thermally responsive hydrogels where degradation or solubilization is determined by their polyester components might be applied to other tissue engineering and regenerative medicine applications where designed biomaterial degradation behavior is needed. PMID:25890745

  13. Mutagenicity of 2-[2-(acetylamino)-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6) and benzo[a]pyrene (BaP) in the gill and hepatopancreas of rpsL transgenic zebrafish.

    PubMed

    Amanuma, Kimiko; Tone, Suguru; Nagaya, Masato; Matsumoto, Michi; Watanabe, Tetsushi; Totsuka, Yukari; Wakabayashi, Keiji; Aoki, Yasunobu

    2008-10-30

    We examined the in vivo mutagenicity of 2-[2-(acetylamino)-4-[bis(2-hydroxyethyl)amino]-5-methoxyphenyl]-5-amino-7-bromo-4-chloro-2H-benzotriazole (PBTA-6) and benzo[a]pyrene (BaP) by using transgenic (Tg) zebrafish carrying the mutational target gene rpsL. PBTA-6 is one of the PBTA-type compounds that were recently identified in highly mutagenic river water in Japan. BaP is a well-known contaminant that is frequently found in polluted water. Both compounds are potent mutagens, as determined by using the Ames test employing S9 mix and Salmonella. Adult rpsL Tg zebrafish were exposed to 0, 7, or 10 mg/L PBTA-6 or 0, 1.5, or 3 mg/L BaP for 96 h in a water bath and the mutations in their gills and hepatopancreata were measured 2-4 weeks later. At 3 weeks after exposure, 3 mg/L BaP significantly increased the rpsL mutant frequency (MF) in the gill and hepatopancreas by 5- and 2.3-fold, respectively, as compared to control fish. Sequence analysis showed that BaP mainly induced G:C to T:A and G:C to C:G transversions, which is consistent with the known mutagenic effects of BaP. In contrast, despite its extremely high mutagenic potency in Salmonella strains, PBTA-6 did not significantly increase the MF in the zebrafish gill or hepatopancreas. Although PBTA-6 is 300 times more mutagenic than BaP in the Ames test [T. Watanabe, H. Nukaya, Y. Terao, Y. Takahashi, A. Tada, T. Takamura, H. Sawanishi, T. Ohe, T. Hirayama, T. Sugimura, K. Wakabayashi, Synthesis of 2-phenylbenzotriazole-type mutagens, PBTA-5 and PBTA-6, and their detection in river water from Japan, Mutat. Res. 498 (2001) 107-115], calculation of the mutagenicity per mole of compound indicated that PBTA-6 was 33- and <3.7-fold less mutagenic in the zebrafish gill and hepatopancreas, respectively, than BaP. PMID:18675378

  14. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction.

    PubMed

    Marshall, William G; Urquhart, Andrew J; Oswald, Iain D H

    2015-09-10

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low pressures. The first is observed at 0.39 GPa, where both phases were observed simultaneously and confirm our previous observations. This transition is followed by a second transition at 1.2 GPa to a new polymorph that is characterized for the first time. On increasing pressure, the diffraction pattern of phase III deteriorates significantly. On decompression phase III persists to 0.54 GPa before transformation to the ambient pressure phase. There is significant loss of signal after decompression, signifying that there has been a loss of material through polymerization. The orientation of the molecules in phase III provides insight into the possible polymerization reaction. PMID:26289930

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Synthesis and characterization of magnetic poly(glycidyl methacrylate) microspheres

    NASA Astrophysics Data System (ADS)

    Horák, Daniel; Petrovský, Eduard; Kapička, Aleš; Frederichs, Theodor

    2007-04-01

    Magnetic nanoparticles encapsulated in poly(glycidyl methacrylate) microspheres were prepared and their detailed structural and magnetic characteristics given. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with dextran, (carboxymethyl)dextran or tetramethylammonium hydroxide. The microspheres were prepared by emulsion or dispersion polymerization of glycidyl methacrylate in the presence of ferrofluid. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres. Blocking temperature was not observed, suggesting the absence of magnetic interactions at low temperatures. This is most probably caused by complete encapsulation and the absence of agglomeration. Such microspheres can be used in biomedical applications.

  20. 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.

  1. 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. PMID:23538596

  2. [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. PMID:20377062

  3. Biodegradation of polystyrene, poly(metnyl methacrylate), and phenol formaldehyde.

    PubMed Central

    Kaplan, D L; Hartenstein, R; Sutter, J

    1979-01-01

    The biodegradation of three synthetic 14C-labeled polymers, poly(methyl methacrylate), phenol formaldehyde, and polystyrene, was studied with 17 species of fungi in axenic cultures, five groups of soil invertebrates, and a variety of mixed microbial communities including sludges, soils, manures, garbages, and decaying plastics. Extremely low decomposition rates were found. The addition of cellulose and mineral failed to increase decomposition rates significantly. PMID:533278

  4. 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.

  5. Different in vitro and in vivo behaviors between Poly(carboxybetaine methacrylate) and poly(sulfobetaine methacrylate).

    PubMed

    Lin, Weifeng; Ma, Guanglong; Wu, Jiang; Chen, Shengfu

    2016-10-01

    Poly(sulfobetaine methacrylate) (pSBMA) and poly(carboxybetaine methacrylate) (pCBMA) are two well-known zwitterionic polymers known for their excellent antifouling properties. In this work, these two zwitterionic polymers were compared both in vitro and in vivo. Both of them exhibited excellent antifouling properties and low macrophage uptake although there were negligible differences in resistance to nonspecific protein adsorption of their hydrogels and cell internalization of their star polymers. However, it is found that the β- Cyclodextrin-CBMA (CD-CBMA) showed a circulation time one order of magnitude longer than CD-SBMA, which implied that small differences in vitro may lead to a dramatic difference in vivo. This work demonstrated that pCBMA showed greater potential than pSBMA in biomedical applications. PMID:27459415

  6. Dielectric relaxation study of mixtures of alkyl methacrylates and 1-alcohols using time-domain reflectometry

    NASA Astrophysics Data System (ADS)

    Sivagurunathan, P.; Dharmalingam, K.; Ramachandran, K.; Prabhakar Undre, B.; Khirade, P. W.; Mehrotra, S. C.

    2006-05-01

    Dielectric relaxation measurements on alkyl methacrylates (methyl methacrylate, ethyl methacrylate and butyl methacrylate) with 1-alcohols (1-propanol, 1-pentanol, 1-heptanol, 1-octanol and 1-decanol) have been carried out using time-domain reflectometry (TDR) over the frequency range 10 MHz to 20 GHz at 303 K for different concentrations of alcohols. The dielectric parameters, namely the static dielectric constant (ɛ0), the dielectric constant at microwave frequencies (ɛ∞) and the relaxation time (τ) were determined. The Kirkwood correlation factor, which contains information regarding solute-solvent interaction and corresponding structural information, the excess permittivity and the excess inverse relaxation time were also determined. The values of the static dielectric constant and the relaxation time increase with the percentage of alkyl methacrylates in the alcohol, whereas the static dielectric constant decreases and the relaxation time increases with an increase in the alkyl chain length of both the methacrylates and the alcohols.

  7. Heterocyclic methacrylates for clinical applications. II. Room temperature polymerizing systems for potential clinical use.

    PubMed

    Patel, M P; Braden, M

    1991-09-01

    A number of useful room temperature polymerizing resins were formulated, based on poly(ethyl methacrylate) powder and a range of low shrinkage heterocyclic methacrylate monomers. N,N-dimethyl-p-toluidine or p-tolyl diethanolamine were used as activating amines, but the latter material is less active and some care is necessary with respect to the source of the monomer. Isobornyl methacrylate is a useful diluent monomer to reduce the exotherm. PMID:1742408

  8. Effect of Photoinitiator System and Water Content on Dynamic Mechanical Properties of a Light-cured bisGMA/HEMA Dental Resin

    PubMed Central

    Park, Jonggu; Ye, Qiang; Topp, Elizabeth M.; Misra, Anil; Kieweg, Sarah L.; Spencer, Paulette

    2009-01-01

    The selection of an appropriate photoinitiator system is critical for efficient polymerization of dental resins with satisfactory mechanical and physical properties. The purpose of this study was to evaluate the influence of adding an iodonium salt to two-component photoinitiator systems. Four photoinitiator systems were included in a model bisGMA/HEMA resin and used to prepare samples at different water contents; the dynamic mechanical properties and the final degree of conversion of the samples were then characterized. Addition of the iodonium salt to the two-component photoinitiator systems increased the final degree of conversion, glass transition temperature, rubbery modulus, and crosslink density. The photoinitiator system containing ethyl-4-(dimethylamino) benzoate as a co-initiator and the iodonium salt exhibited the highest rubbery modulus. The enhanced properties in the presence of the iodonium salt can be attributed to the production of an active phenyl radical with regeneration of the original camphorquinone, which may increase the compatibility between monomers and initiators, especially in the presence of water. The results support the hypothesis that a photoinitiator system containing an iodonium salt can increase both mechanical properties and final conversion of model resin polymerized in the presence of water. PMID:19827107

  9. Study of the miscibility of poly(styrene-co-4-vinylbenzoic acid) with poly(ethyl methacrylate) or with poly[ethyl methacrylate-co-(2-N,N-dimethylaminoethyl) methacrylate] by inverse gas chromatography.

    PubMed

    Ourdani, Samia; Amrani, Farouk

    2002-09-01

    Poly(styrene) is immiscible with poly(ethyl methacrylate). The introduction of a small amount of 4-vinylbenzoic acid units along poly(styrene) chains (PS-VBA) enhanced its miscibility with poly(ethyl methacrylate) (PEMA) or with poly[ethyl methacrylate-co-(2-N,N-dimethylaminoethyl) methacrylate] (PEMA-DAE), as observed from the appearance of a single composition dependent glass transition temperature for each binary system using inverse gas chromatography. The negative values of the apparent polymer-polymer interaction parameter, chi(23)app, determined with different families of molecular probes, for three blend compositions and over a range of temperature confirm quantitatively the miscibility of these blends. The chi(23)app values for PEMA(PS-VBA) and (PEMA-DAE)-(PS-VBA) blends are dependent of the chemical nature of the probes, the temperature and the blend composition. PMID:12385399

  10. Glycol methacrylate in light microscopy: nucleic acid cytochemistry.

    PubMed

    Cole, M B; Ellinger, J

    1981-07-01

    Techniques utilizing Feulgen, azure B bromide, methyl green-pyronin, gallocyanin chromalum and cresyl violet stains have been modified and adapted for visualizing nucleic acids in 0.5-2.0 micrometer sections of tissues embedded in glycol methacrylate (GMA). Methods for evaluating the stain specificity for DNA and RNA using deoxyribonuclease and ribonuclease digestions, aldehyde blocking, and acid extractions are also described. The specificity of the stains in GMA embedded tissues is comparable to that reported for paraffin-embedded tissues. PMID:6167720

  11. Density of radiolytic gas bubbles in polymethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Makkonen, T.; Tiainen, O. J. A.; Valkiainen, M.; Winberg, M.

    The density of the radiolytic gas bubbles in irradiated polymethyl methacrylate was measured during subsequent heat treatment as a function of radiation dose. The samples were irradiated in the core of the Triga Mark II reactor in Otaniemi. After the irradiation periods the samples were heat treated at 393 K. The number of the bubbles could be explained by a thermal activation model. The bubbles are born in material inhomogeneities and the threshold dose for the bubble initiation was about 25 Mrad for the heat treatment at 393 K under the atmospheric pressure.

  12. Jumpwise deformation of polymethyl methacrylate in the microplasticity region

    NASA Astrophysics Data System (ADS)

    Shpeizman, V. V.; Yakushev, P. N.; Mukhina, Zh. V.; Kuznetsov, E. V.; Smolyanskii, A. S.

    2013-05-01

    The deformation rate with a step of 325 nm has been measured under uniaxial compression at the initial stage of creep and shape recovery of a polymethyl methacrylate (PMMA) sample after unloading. The effect of low γ-ray doses and magnetic fields on the deformation has been studied. It has been shown that a weak pre-exposure of the PMMA sample structure to radiation and magnetic fields can cause a slight hardening in the microplasticity region. The deformation jump sizes have been determined on micro- and nanoscales. The effect of irradiation and magnetic fields manifests itself as redistributed contributions of various jumps to the deformation.

  13. Hardness of irradiated poly(methyl methacrylate) at elevated temperatures

    SciTech Connect

    Lu, K.-P.; Lee, Sanboh; Cheng, Cheu Pyeng

    2001-08-15

    The decrease in hardness induced by gamma irradiation in poly(methyl methacrylate) (PMMA) has been investigated. The hardness is assumed to decrease linearly with the concentration of radiation-induced defects. Annealing at high temperatures induces defect annihilation as tracked by an increase in hardness. The annihilation follows first-order kinetics during isothermal annealing. The dependence of hardness on the reciprocal of the time constant satisfies the Arrhenius equation, and the corresponding activation energy of the kinetic process decreases with increasing dose. The hardness of postannealed PMMA decreases linearly with increasing dose. {copyright} 2001 American Institute of Physics.

  14. The immobilization of enzymes onto poly(ethylene)—g.co—methacrylic acid, [poly(ethylene)—g.co—hydroxyethyl methacrylate]—g.co—methacrylic acid and [poly(ethylene)—g.co—methacrylic acid]—g.co—hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Da Silva, M. Alves; Gil, M. H.; Guiomar, J.; Lapa, E.; Machado, E.; Moreira, M.; Guthrie, J. T.; Kotov, S.

    A series of graft copolymers has been prepared based on the poly(ethylene) backbone. These carry functional groups which are effective in coupling and provide a level of hydrophilicity which is thought to be consistent with generating a suitable micro-environment for enzyme immobilization and subsequent enhanced biocatalyst stability. Four enzymes have been immobilized. These are papain, trypsin, glucose oxidase and α-chymotrypsin. The parent copolymers were assembled via radiation-induced grafting. Secondary grafting was achieved in two ways. The first involved grafting methacrylic acid onto poly(ethylene)—g.co—hydroxyethyl methacrylate, while the second involved grafting hydroxyethyl methacrylate onto poly(ethylene)—g.co—methacrylic acid. The results suggest that a high degree of specificity arises in the systems examined with regard to the enzymes, the type of copolymers and the coupling procedures. Generally, relatively large amounts of enzyme become covalently attached to the copolymers, though the overall level of activity is low. In this work it has been observed that the most satisfactory results were obtained when the partly hydrolyzed poly(ethylene)—g.co—hydroxyethyl methacrylate was used in the immobilization of the biocatalysts.

  15. The Dependence of MG63 Osteoblast Responses to (Meth)Acrylate-based Networks on Chemical Structure and Stiffness

    PubMed Central

    Smith, Kathryn E.; Hyzy, Sharon L.; Sunwoo, MoonHae; Gall, Ken; Schwartz, Zvi; Boyan, Barbara D.

    2010-01-01

    The cell response to an implant is regulated by the implant’s surface properties including topography and chemistry, but less in known about how the mechanical properties affect cell behavior. The objective of this study was to evaluate how the surface stiffness and chemistry of acrylate-based copolymer networks affect the in vitro response of human MG63 pre-osteoblast cells. Networks comprised of poly(ethylene gycol) dimethacrylate (PEGDMA; Mn~750) and diethylene glycol dimethacrylate (DEGDMA) were photopolymerized at different concentrations to produce three compositions with moduli ranging from 850 to 60MPa. To further decouple chemistry and stiffness, three networks comprised of 2-hydroxyethyl methacrylate (2HEMA) and PEGDMA or DEGDMA were also designed that exhibited a range of moduli similar to the PEGDMA-DEGDMA networks. MG63 cells were cultured on each surface and tissue culture polystyrene (TCPS), and the effect of copolymer composition on cell number, osteogenic markers (alkaline phosphatase specific activity and osteocalcin), and local growth factor production (OPG, TGF-β1, and VEGF-A) was assessed. Cells exhibited a more differentiated phenotype on the PEGDMA-DEGDMA copolymers compared to the 2HEMA-PEGDMA copolymers. On the PEGDMA-DEGDMA system, cells exhibited a more differentiated phenotype on the stiffest surface indicated by elevated osteocalcin compared with TCPS. Conversely, cells on 2HEMA-PEGDMA copolymers became more differentiated on the less stiff 2HEMA surface. Growth factors were regulated in a differential manner. These results indicate that copolymer chemistry is the primary regulator of osteoblast differentiation, and the effect of stiffness is secondary to the surface chemistry. PMID:20510445

  16. Effect of Two Novel Sustained-Release Drug Delivery Systems on Bleb Fibrosis: An In Vivo Glaucoma Drainage Device Study in a Rabbit Model

    PubMed Central

    Schoenberg, Evan D.; Blake, Diane A.; Swann, F. Beau; Parlin, Andrew W.; Zurakowski, David; Margo, Curtis E.; Ponnusamy, Thiruselvam; John, Vijay T.; Ayyala, Ramesh S.

    2015-01-01

    Purpose: To evaluate two drug delivery systems, a nonbiodegradable poly(2-hydroxyethyl methacrylate) (P[HEMA]) system with mitomycin C (MMC) and a biodegradable poly(lactic-co-glycolic acid) (PLGA) system with 5-fluorouracil (5-FU) with and without MMC for their ability to reduce fibrosis when attached to an Ahmed glaucoma valve (AGV) and implanted in a rabbit model. Methods: New Zealand albino rabbits (48) were divided into six equal groups, and AGVs, modified as described below, were implanted in the right eye of each rabbit. The groups included (1) PLGA alone; (2) P(HEMA) plus MMC (6.5 μg); (3) PLGA plus 5-FU (0.45 mg); (4) PLGA plus 5-FU (1.35 mg); (5) PLGA plus 5-FU and MMC (0.45 mg and 0.65 μg, respectively); (6) PLGA plus 5-FU and MMC (1.35 mg and 0.65 μg, respectively). The rabbits were followed for 3 months prior to euthanasia. Results: The bleb wall thickness was significantly less in groups 2, 5, and 6 compared to the rest. At 3 months, the PLGA polymer had completely disappeared, while the P(HEMA) polymer remained intact. There were no statistical differences in the degree of clinically graded conjunctival injection, histologic inflammation, or histologic fibrosis among the six groups. Conclusions: We successfully created a sustained-release drug delivery system that decreased the postoperative fibrosis using both a nonbiodegradable P(HEMA) polymer and a biodegradable (PLGA) polymer. Both systems appear to work equally well with no side effects. Translational Relevance: These results are supportive of the antifibrotic effect of the slow-release drug delivery system following glaucoma drainage device implantation, thus paving the way for human pilot studies. PMID:26046006

  17. Selective determination of pharmaceuticals and illicit drugs in wastewaters using a novel strong cation-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

    PubMed

    Gilart, Núria; Cormack, P A G; Marcé, Rosa Maria; Fontanals, Núria; Borrull, Francesc

    2014-01-17

    In this study, two materials are presented with strong cation-exchange (SCX) behaviour synthesised by two different approaches and then crushed for their application as sorbents for solid-phase extraction (SPE) to extract a group of pharmaceuticals and illicit drugs selectively from wastewater samples. The first SCX polymer was obtained by copolymerisation of three monomers: 2-acrylamido-2-methylpropane sulphonic acid (AMPSA), 2-hydroxyethyl methacrylate (HEMA) and pentaerythritol triacrylate (PETRA), while the second was obtained by post-modification with sulphuric acid (H2SO4) of a copolymer based on HEMA and divinylbenzene (DVB). After their syntheses, both polymers were evaluated as SPE sorbents, with all parameters affecting SPE being optimised, such as sample pH, washing and elution solvents and volumes. Thanks to the sulphonic groups present in the structure of the polymers, all of the compounds with basic functionalities were retained on the sorbents after the washing step, removing the acidic analytes and other interfering compounds, providing successful results in terms of ion suppression/enhancement (-12% and 21%) when wastewater samples were analysed. However, AMPSA/HEMA/PETRA (20/60/20) failed to retain the analytes after loading wastewater samples (25 or 50mL), decreasing analyte recovery values significantly, whereas the sulphonated HEMA/DVB (50/50) enabled good SPE performance with recovery values between 70% and 98%, except for ranitidine and EDDP (39% and 43%, respectively). Therefore, this polymer was selected for further method validation and quantification of wastewater samples, providing low method detection limits (MDLs) in this matrix (from 2 to 40ngL(-1)). Finally, most of the studied compounds were detected and quantified in wastewater samples, especially atenolol, ranitidine, cocaine and its metabolite benzoylecgonine. PMID:24369996

  18. RAFT dispersion polymerization of 3-phenylpropyl methacrylate with poly[2-(dimethylamino)ethyl methacrylate] macro-CTAs in ethanol and associated thermoreversible polymorphism.

    PubMed

    Pei, Yiwen; Dharsana, Nadia C; van Hensbergen, Johannes A; Burford, Robert P; Roth, Peter J; Lowe, Andrew B

    2014-08-21

    The direct synthesis of methacrylic-based soft polymeric nanoparticles via reversible addition-fragmentation chain transfer dispersion polymerization (RAFTDP) is described. The use of poly[2-(dimethylamino)ethyl methacrylate]s, of varying average degree of polymerization (X¯n), as the stabilizing blocks for the RAFTDP of 3-phenylpropyl methacrylate (PPMA) in ethanol at 70 °C, at various total solids contents, yielded the full spectrum of self-assembled nanoparticles (spherical and worm aggregates and polymersomes). We also demonstrate that nanoparticle morphology can be tuned simply by controlling temperature. This is especially evident in the case of worm aggregates undergoing a thermoreversible transition to spherical species - a process that is accompanied by a macroscopic degelation-gelation process. PMID:24975501

  19. Preparation of Novel Poly(hydroxyethyl methacrylate-coglycidyl methacrylate)-Grafted Core-Shell Magnetic Chitosan Microspheres and Immobilization of Lactase

    PubMed Central

    Zhao, Wei; Yang, Rui-Jin; Qian, Ting-Ting; Hua, Xiao; Zhang, Wen-Bin; Katiyo, Wendy

    2013-01-01

    Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6–17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization. PMID:23743822

  20. Backfilling-Free Strategy for Biopatterning on Intrinsically Dual-Functionalized Poly[2-Aminoethyl Methacrylate-co-Oligo(Ethylene Glycol) Methacrylate] Films.

    PubMed

    Lee, Bong Soo; Lee, Juno; Han, Gyeongyeop; Ha, EunRae; Choi, Insung S; Lee, Jungkyu K

    2016-07-20

    We demonstrated protein and cellular patterning with a soft lithography technique using poly[2-aminoethyl methacrylate-co-oligo(ethylene glycol) methacrylate] films on gold surfaces without employing a backfilling process. The backfilling process plays an important role in successfully generating biopatterns; however, it has potential disadvantages in several interesting research and technical applications. To overcome the issue, a copolymer system having highly reactive functional groups and bioinert properties was introduced through a surface-initiated controlled radical polymerization with 2-aminoethyl methacrylate hydrochloride (AMA) and oligo(ethylene glycol) methacrylate (OEGMA). The prepared poly(AMA-co-OEGMA) film was fully characterized, and among the films having different thicknesses, the 35 nm-thick biotinylated, poly(AMA-co-OEGMA) film exhibited an optimum performance, such as the lowest nonspecific adsorption and the highest specific binding capability toward proteins. PMID:27252120

  1. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... weight of methyl methacrylate; and (2) 21 to 27 parts by weight of a grafted rubber consisting of (i) 16... 28 parts by weight of styrene and (ii) 5 to 10 parts by weight of a graft polymer having the...

  2. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... weight of methyl methacrylate; and (2) 21 to 27 parts by weight of a grafted rubber consisting of (i) 16... 28 parts by weight of styrene and (ii) 5 to 10 parts by weight of a graft polymer having the...

  3. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... weight of methyl methacrylate; and (2) 21 to 27 parts by weight of a grafted rubber consisting of (i) 16... 28 parts by weight of styrene and (ii) 5 to 10 parts by weight of a graft polymer having the...

  4. ACUTE TOXICITY AND BEHAVIORAL EFFECTS OF ACRYLATES AND METHACRYLATES TO JUVENILE FATHEAD MINNOWS (JOURNAL VERSION)

    EPA Science Inventory

    Acrylate and methacrylate esters are reactive monomers that are used primarily in the synthesis of acrylic plastics and polymers. Ninety-six hour flow-through acute toxicity tests were conducted with fathead minnows (Pimephales promelas) using 6 acrylates and 6 methacrylates. Nin...

  5. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate, reaction... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydroxypropyl methacrylate, reaction... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  6. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate, reaction... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydroxypropyl methacrylate, reaction... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  7. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate, reaction... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydroxypropyl methacrylate, reaction... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  8. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  9. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  10. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  11. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  12. Adsorption of water vapor on modified methacrylate polymeric sorbents

    SciTech Connect

    Platonova, N.P.; Tataurova, O.G.; Vartapetyan, R.Sh.

    1995-12-31

    Adsorption of water vapor on methacrylate copolymers and terpolymers was studied. An increase in the content of the cross-linking agent gives rise to increase in the limiting adsorption of water vapor at the saturation pressure (a{sub s}) and to decrease in the concentration of primary adsorption centers. Modification of the initial copolymer containing 60% of 2,3-epoxypropyl methacrylate (EPMA) monomer and 40% of cross-linking agent, ethylene dimethacrylate, with diethylenetriamine (DETA) results in an increase in the a{sub s} value, while modification with C{sub 12} and C{sub 18} alkyl, benzyl, and phenyl groups gives rise to decrease in the a{sub s} values for the copolymeric sorbents. The concentration of primary adsorption centers (a{sub m}) increases considerably on modification of the copolymer with DETA and C{sub 12} groups and decreases markedly on modification with benzyl and phenyl groups. For terpolymers, containing EPMA and styrene, an increase in the styrene/EPMA ratio reduces the a{sub s}, and a{sub m} values. The copolymer modified with DETA groups possesses the most hydrophilic properties, while the copolymer modified with benzyl group exhibits the most hydrophobic properties. The mechanism of adsorption of water molecules on the polymers is discussed.

  13. Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning

    NASA Astrophysics Data System (ADS)

    Cengiz, Ugur; Avci, Merih Z.; Erbil, H. Yildirim; Sarac, A. Sezai

    2012-05-01

    A new statistical terpolymer containing perfluoroethyl alkyl methacrylate (Zonyl-TM), methyl methacrylate and butyl acrylate, poly(Zonyl-TM-ran-MMA-ran-BA) was synthesized in supercritical carbon dioxide at 200 bar and 80 °C using AIBN as an initiator by heterogeneous free radical copolymerization. Nanofibers of this terpolymer were produced by electrospinning from its DMF solution. The structural and thermal properties of terpolymers and electrospun poly(Zonyl-TM-MMA-BA) nanofibers were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry. Nanofiber morphology was investigated by scanning electron microscopy. Electrospun nanofiber layer was found to be superhydrophobic with a water contact angle of 172 ± 1° and highly oleophobic with hexadecane, glycerol and ethylene glycol contact angles of 70 ± 1°, 167 ± 1° and 163 ± 1° respectively. The change of the contact angle results on the electrospun fiber layer and flat terpolymer surfaces by varying feed monomer composition were compared and discussed in the text.

  14. Novel syngas-based process for methyl methacrylate

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Choi, G.N.; Tam, S.S.; Tischer, R.E.; Srivastava, R.D.

    1996-12-31

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel are developing a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Pittsburgh Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the research on propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees}C and 180 atm). Bechtel has performed an extensive cost analysis, which shows that Eastman`s propionate synthesis process is competitive with other technologies to produce the anhydride. In the second step, RTI and Eastman have developed active and stable V-SI-P and Ta metal oxide catalysts for condensation reactions of propionates with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst activity. Current research focuses on enhancing the condensation reaction yields, acid-base properties, in situ condensation in a high- temperature, high-pressure (HTHP) slurry reactor, and alternate formaldehyde feedstocks. Based on Eastman and RTI laboratory reactor operating data, a cost estimate is also being developed for the integrated process.

  15. Synthesis of Methyl Methacrylate from Coal-Derived Syngas

    SciTech Connect

    Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Makarand R. Gogate; Richard D. Colberg; Samuel S. Tam

    1998-04-17

    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. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is 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 month, RTI has finalized the design of a fixed-bed microreactor system for DME partial oxidation reactions. RTI incorporated some design changes to the feed blending system, so as to be able to blend varying proportions of DME and oxygen. RTI has also examined the flammability limits of DME-air mixtures. Since the lower flammability limit of DME in air is 3.6 volume percent, RTI will use a nominal feed composition of 1.6 percent in air, which is less than half the lower explosion limit for DME-air mixtures. This nominal feed composition is thus considered operationally safe, for DME partial oxidation reactions. RTI is also currently developing an analytical system for DME partial oxidation reaction system.

  16. Sulfone-Containing Methacrylate Homopolymers: Wetting and Thermal Properties.

    PubMed

    Fujii, Shota; McCarthy, Thomas J

    2016-01-26

    Although the sulfonyl functional group has a large dipole moment and compounds containing them (sulfones) have correspondingly high dielectric constants, this chemical structure has been neglected for use as a functional group to render surfaces hydrophilic. We have prepared three methacrylate polymers containing side chains capped with sulfolane, methylsulfone, and ethylsulfone functionality. The sulfolane-containing polymer exhibits an unusually high glass transition temperature (Tg = 188°C) for a methacrylate polymer and slightly different thermal degradation behavior than the other two sulfone-containing polymers, likely due to the bulky structure of the sulfolane group in the polymer side chain. At macroscopic polymer film/water interfaces, the sulfone-containing side chains exposed to the interface impart hydrophilic properties as assessed by contact angle analysis. The hydrophilicities of sulfolane and methylsulfone surfaces are similar, and greater than the ethylsulfone surface. Although the chemical compositions of the sulfolane and ethylsulfone polymers are almost identical, the five-membered ring structure of sulfolane allows the sulfonyl moiety to be exposed at the interface in a manner similar to that of the methylsulfone polymer. The sulfonyl group at the ethylsulfone polymer/water interface is slightly masked by the ethyl group. Interestingly, the sulfolane surface displays a higher affinity to methylene iodide and n-hexadecane probe fluids compared to the other sulfone surfaces, suggesting that the five-membered ring structure of the sulfolane moiety can orient in a manner that shelters the sulfonyl group at hydrophobic interfaces. PMID:26716766

  17. The acute aquatic toxicity of a series of acrylate and methacrylate esters

    SciTech Connect

    Staples, C.A.; McLaughlin, J.E.; Hamilton, J.D.

    1994-12-31

    Acute aquatic toxicity data for several acrylate and methacrylate esters were reviewed. Acrylates included acrylic acid, ethyl-, and butyl-acrylate. Methacrylates included methacrylic acid, methyl-, and butyl-methacrylate. Tests were 48 hr or 96 hr standard flow through (invertebrates and fish) assays (measured exposure concentrations). These data are currently used in a risk assessment of acrylate/methacrylate environmental safety. Algal growth (Selanastrum capricomutum) 96 hr EC{sub 50}s were 0.17 mg/L (NOEC < 0.13 mg/L) for acrylic acid, 11.0 mg/L (NOEC < 6.5 mg/L) for ethyl acrylate, and 5.2 mg/L (NOEC < 3.8 mg/L) for butyl acrylate. Invertebrate (Daphnia magna) 48 hr LC{sub 50}s were 95.0 mg/L (NOEC 23.0 mg/L) for acrylic acid, 7.9 mg/L (NOEC 3.4 mg/L) for ethyl acrylate, and 8.2 mg/L (NOEC 2.4 mg/L) for butyl acrylate. Rainbow trout (Oncorhynchus mykiss) 96 hr LC{sub 50}s were 27.0 mg/L (NOEC 6.3 mg/L) for acrylic acid, 4.6 mg/L (NOEC 0.78 mg/L) for ethyl acrylate, and 5.2 mg/L (NOEC 3.8 mg/L) for butyl acrylate. Algae 96 hr EC{sub 50}s were 0.59 mg/L (NOEC 0.38 mg/L) for methacrylic acid, 170.0 mg/L (NOEC 100.0 mg/L) for methyl methacrylate, and 130.0 mg/L for butyl methacrylate. Daphnia magna 48 hr LC{sub 50}s were > 130.0 mg/L (NOEC 130.0 mg/L) for methacrylic acid, 69.0 mg/L (NOEC 48.0 mg/L) for methyl methacrylate, and 32.0 mg/L (NOEC 23.0 mg/L) for butyl methacrylate. Trout 96 hr LC{sub 50}s were 85.0 mg/L (NOEC 12.0 mg/L) for methacrylic acid and > 79.0 mg/L (NOEC 40.0 mg/L) for methyl methacrylate. The fathead minnow (Pimephales promelas) 96 hr LC{sub 50} was 11.0 mg/L for butyl methacrylate.

  18. Investigation of infrared calibration methods for application to the study of methyl methacrylate polymerization.

    PubMed

    Kaczmarczyk, B; Morejko-Buz, B; Stolarzewicz, A

    2001-08-01

    Infrared spectroscopy has been used to monitor the polymerization of methyl methacrylate. Concentrations of methyl methacrylate in the reaction mixture were determined by use of three calibration methods. Classical quantitative analysis was used to measure the height of the stretching vibration bands of the vinyl group at 1639 cm(-1). A calibration procedure using the considerably higher intensity of the C = O stretching vibration band of the carbonyl ester group at 1725 cm(-1) seemed useful only for high concentrations of methyl methacrylate, i.e. at the beginning of reaction, because this band overlaps that of poly(methyl methacrylate). Use of second-derivative spectra and measuring their values at 1725 cm(-1) enabled estimation of ten times lower concentrations of methyl methacrylate the calibration using the band from the vinyl group. PMID:11569872

  19. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG

    1999-01-20

    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(Oct.-Dec./98), we have investigated the condensation between methyl propionate and formaldehyde (MP/HCHO=4.5/1) at various reaction temperatures(280-360EC) over 5%, 10%, and 20% Nb O /SiO catalysts. The conversion of HCHO increases with reaction 2 5 2 temperature and niobium loading. MMA+MAA selectivity goes through a maximum with the temperature over both 10% and 20% Nb O /SiO . The selectivities to MMA+MAA are 67.2%, 2 5 2 72.3%and 58.1% at 320EC over 5%, 10%, 20% Nb O /SiO , respectively. However, the 2 5 2 conversion of formaldehyde decreases rapidly with time on stream. The results suggest that silica supported niobium catalysts are active and selective for condensation of MP with HCHO, but deactivation needs to be minimized for the consideration of commercial application. We have preliminarily investigated the partial oxidation of dimethyl ether(DME) over 5% Nb O /SiO catalyst. Reactant gas mixture of 0.1% DME, 0.1% O and balance nitrogen is 2 5 2 2 studied with temperature ranging from 200°C to 500°C. The conversion of DME first increases with temperature reaching an maximum at 400°C then decreases. The selectivity to HCHO also increases with reaction temperature first. But the selectivity to HCHO decreases at temperature above 350

  20. Polyethyleneimine assisted-two-step polymerization to develop surface imprinted cryogels for lysozyme purification.

    PubMed

    Erol, Kadir; Köse, Kazım; Uzun, Lokman; Say, Rıdvan; Denizli, Adil

    2016-10-01

    Surface imprinting strategy is one of the promising approaches to synthesize plastic antibodies while overcoming the problems in the protein imprinting research. In this study, we focused our attentions on developing two-step polymerization to imprint on the bare surface employing polyethyleneimine (PEI) assisted-coordination of template molecules, lysozyme. For this aim, we firstly synthesized poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA) cryogels as a bare structure. Then, we immobilized PEI onto the cryogels through the addition reaction between GMA and PEI molecules. After that, we determined the amount of free amine (NH2) groups of PEI molecules, subsequently immobilized methacrylate functionalities onto the half of them and another half was used to chelate Cu(II) ions as a mediator between template, lysozyme and PEI groups. After the characterization of the materials developed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and the micro-computed tomography (μCT), we optimized the lysozyme adsorption conditions from aqueous solution. Before performing lysozyme purification from chicken egg white, we evaluated the effects of pH, interaction time, the initial lysozyme concentration, temperature and ionic strength on the lysozyme adsorption. Moreover, the selectivity of surface imprinted cryogels was examined against cytochrome c and bovine serum albumin (BSA) as the competitors. Finally, the mathematical modeling, which was applied to describe the adsorption process, showed that the experimental data is very well-fitted to the Langmuir adsorption isotherm. PMID:27424087

  1. A Facile Strategy for Catalyst Separation and Recycling Suitable for ATRP of Hydrophilic Monomers Using a Macroligand.

    PubMed

    Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2016-01-01

    How to simply and efficiently separate and recycle catalyst has still been a constraint for the wide application of atom transfer radical polymerization (ATRP), especially for the polymerization systems with hydrophilic monomers because the polar functional groups may coordinate with transition metal salts, resulting in abundant catalyst residual in the resultant water-soluble polymers. In order to overcome this problem, a latent-biphasic system is developed, which can be successfully used for ATRP catalyst separation and recycling in situ for various kinds of hydrophilic monomers for the first time, such as poly(ethylene glycol) monomethyl ether methacrylate (PEGMA), 2-hydroxyethyl methacrylate (HEMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA), N,N-dimethyl acrylamide (DMA), and N-isopropylacrylamide (NIPAM). Herein, random copolymer of octadecyl acrylate (OA), MA-Ln (2-(bis(pyridin-2-ylmethyl)amino)ethyl acrylate), and POA-ran-P(MA-Ln) is designed as the macroligand, and heptane/ethanol is selected as the biphasic solvent. Copper(II) bromide (CuBr2 ) is employed as the catalyst, PEG-bound 2-bromo-2-methylpropanoate (PEG350 -Br) as the water-soluble ATRP initiator and 2,2'-azobis(isobutyronitrile) (AIBN) as the azo-initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP system. Importantly, well-defined water-soluble polymers are obtained even though the recyclable catalyst is used for sixth times. PMID:26506506

  2. Preparation of amphiphilic glycopolymers with flexible long side chain and their use as stabilizer for emulsion polymerization.

    PubMed

    Alvárez-Paino, Marta; Juan-Rodríguez, Rafael; Cuervo-Rodríguez, Rocío; Muñoz-Bonilla, Alexandra; Fernández-García, Marta

    2014-03-01

    A glycomonomer was synthesized from poly(ethylene glycol) methacrylate (PEGMA). The terminal hydroxyl moieties were activated with ester groups and subsequently the glucosamine was incorporated forming urethane linkages. The obtained glycomonomer was copolymerized with methyl acrylate by free radical polymerization varying the initial feed composition to produce different amphiphilic glycopolymers. The glycopolymers were then characterized and compared with the homologous glycopolymers based on 2-{[(D-glucosamin-2-N-yl)carbonyl]oxy}ethyl methacrylate. Both series of glycopolymers were used in emulsion polymerization of methyl acrylate as stabilizers without the addition of any cosurfactant. Although high conversions were not achieved with any of the employed surfactant, the glycopolymers provide good colloidal stability, spherical, monodisperse and small latex particles in comparison with the surfactant-free emulsion polymerization. The latex particles stabilized with the glycosurfactant based on PEGMA, containing a flexible spacer between the backbone and the glucosamine, lead to smooth films whereas the short side chain surfactant from 2-hydroxyethyl methacrylate (HEMA), with higher glass transition temperature, restricts the coalescence of particles and, therefore, the film formation. Moreover, the surface bioactivity of these polymer coatings was examined by analyzing their specific interaction with the lectin, Concanavalin A, Canavalia ensiformis. The specific and successful binding to the Concanavalin A was demonstrated by fluorescence microscopy for both series being more intense with increasing amount of glycounits in the glycopolymer stabilizers. Interestingly, the incorporation of a flexible spacer in the glycopolymer structures enhances the binding activity. PMID:24407696

  3. Surface modification of PVDF membrane via AGET ATRP directly from the membrane surface

    NASA Astrophysics Data System (ADS)

    Meng, Jian-Qiang; Chen, Chun-Lin; Huang, Li-Ping; Du, Qi-Yun; Zhang, Yu-Feng

    2011-05-01

    This contribution demonstrates a method for PVDF microporous membrane modification via surface-initiated activators generated by electron transfer atom transfer radical polymerization (AGET ATRP) directly from the membrane surface. Three hydrophilic polymers, poly(2-(N,N-dimethylamino) ethyl methacrylate) (PDMAEMA), poly(2-oligo (ethylene glycol) monomethyl ether methacrylate) (POEGMA), and poly(2-hydroxyethyl methacrylate) (PHEMA), were grafted from the PVDF membrane surface in aqueous solution at room temperature. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the successful covalent tethering of the polymer chains onto the PVDF membrane surface. The gravimetry results indicated an approximately linear increase of the graft yields, up to about 330 μg/cm 2 for DMAEMA and 470 μg/cm 2 for both HEMA and OEGMA, with the polymerization time. Block copolymer brushes were prepared by chain extension. Water contact angle decreased over 50% for high yields, indicating improved surface hydrophilicity. The effects of the graft polymerization on membrane surface morphology, pore structure and permeability were investigated. It was found that the surface roughness was decreased and the pore size distribution was narrowed. The membrane permeability increased at low graft yields due to the enhanced hydrophilicity and decreased at high graft yields due to the overall reduction of the pore diameters.

  4. Radiation synthesis of nanosilver nanohydrogels of poly(methacrylic acid)

    NASA Astrophysics Data System (ADS)

    Gupta, Bhuvanesh; Gautam, Deepti; Anjum, Sadiya; Saxena, Shalini; Kapil, Arti

    2013-11-01

    Nanosilver nanohydrogels (nSnH) of poly(methacrylic acid) were synthesized and stabilized using gamma irradiation. The main objective of this study was to develop silver nanoparticles and to evaluate the antimicrobial activity. Radiation helps in the polymerization, crosslinking and reduction of silver nitrate as well. Highly stable and uniformly distributed silver nanoparticles have been obtained within hydrogel network by water in oil nanoemulsion polymerization and were evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) respectively. TEM showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network. The mean size of silver nanoparticles ranging is 10-50 nm. The nanohydrogels showed good swelling in water. Antibacterial studies of nSnH suggest that it can be a good candidate as coating material in biomedical applications.

  5. Thiol-ene/methacrylate systems for mechanical damping

    NASA Astrophysics Data System (ADS)

    McNair, Olivia; Senyurt, Askim; Wei, Huanyu; Gould, Trent; Piland, Scott; Hoyle, Charles; Savin, Daniel

    2010-03-01

    Ternary thiol-ene-methacrylate (TEMA) networks as materials for mechanical energy damping are unique to the sports world. Using a photoinitiation process, TEMA systems are formed via an initial thiol-ene step-growth mechanism along with traditional radical polymerization of acrylate and ene monomers. Final networks have two-part morphologies: acrylate homopolymer sectors imbedded in a multi-component mesh. Several (TEMA) systems have been synthesized and analyzed via thermal and mechanical probing. Initial studies on these ternary systems have shown excellent properties compared to traditional ethylene vinyl alcohol (EVA) copolymers. For example, PEMA networks exhibit glass transition temperatures 33 K higher than EVA, resulting in improved damping at room temperature. This research will help develop relationships between tan delta, glass transition and their effects on mechanical energy damping for ternary (TEMA) systems.

  6. Interaction between N-vinylpyrrolidone and methyl methacrylate

    NASA Astrophysics Data System (ADS)

    Zaitseva, V. V.; Shtonda, A. V.; Tyurina, T. G.; Bagdasarova, A. R.; Zaitsev, S. Yu.

    2014-04-01

    It is established that the interaction of the isomers of N-vinylpyrrolidone (NVP) and methyl methacrylate (MMA) leads to the formation of molecular π-H- and H-complexes with energies within the limits of 10.2-13.6 (AM1) or 18.2-24.0 (B3LYP/6-311++G( d)) kJ/mol. The structures of complex-bound molecules are examined with respect to changes in the charges on terminal -C1=C2- groups, the distance between them and atoms in an H-bond, and the presence of combined overlapping molecular orbitals (MOs). The presence of an averaged complex that includes presumably all possible structures and allows us to perform the copolymerization of specified monomers in the absence of an initiator is confirmed by means of UV and NMR spectroscopy.

  7. Atom Transfer Radical Polymerization of Methacrylic Acid: A Won Challenge.

    PubMed

    Fantin, Marco; Isse, Abdirisak A; Venzo, Alfonso; Gennaro, Armando; Matyjaszewski, Krzysztof

    2016-06-15

    Polymerization of acidic monomers is one of the biggest challenges for atom transfer radical polymerization (ATRP). An intramolecular cyclization reaction leading to the loss of the C-X chain-end functionality was found to be the main reason for the partial termination of the growing polymer chains. Three approaches were used to overcome this problem: using Cl as the chain-end halogen, lowering the pH (to 0.9), and increasing polymerization rate. Methacrylic acid (MAA) was polymerized by both electrochemically mediated ATRP and supplemental activator and reducing agent ATRP up to high conversion (>90%), in t ≤ 4 h at 25 °C, using inexpensive and nontoxic reagents (NaCl, diluted HCl, water). Control over molecular weight (MW) dispersity was satisfactory, and MWs were in agreement with theoretical values. The "livingness" of the process was confirmed by an electrochemical switch, used to repeatedly and periodically deactivate/reactivate growing chains. PMID:27244091

  8. Chest wall reconstruction with methacrylate prosthesis in Poland syndrome.

    PubMed

    Arango Tomás, Elisabet; Baamonde Laborda, Carlos; Algar Algar, Javier; Salvatierra Velázquez, Angel

    2013-10-01

    Poland syndrome is a rare congenital malformation. This syndrome was described in 1841 by Alfred Poland at Guy's Hospital in London. It is characterized by hypoplasia of the breast and nipple, subcutaneous tissue shortages, lack of the costosternal portion of the pectoralis major muscle and associated alterations of the fingers on the same side. Corrective treatment of the chest and soft tissue abnormalities in Poland syndrome varies according to different authors. We report the case of a 17-year-old adolescent who underwent chest wall reconstruction with a methyl methacrylate prosthesis. This surgical procedure is recommended for large anterior chest wall defects, and it prevents paradoxical movement. Moreover it provides for individual remodeling of the defect depending on the shape of the patient's chest. PMID:23453291

  9. Management of complication after breast augmentation with methacrylate

    PubMed Central

    Grella, Roberto; Almadori, Aurora; D’Ari, Antonio; Romanucci, Vincenza; D’Andrea, Francesco

    2015-01-01

    Introduction Several alloplastic biomaterials are available for injection to the breast, nevertheless not all of them are approved for biomedical use. Although in North America and Western Europe experience with synthetic biomaterials for breast augmentation is very limited, migratory streams might expose physicians worldwide to manage the related complications of these procedures. The aim of this study was to share with other surgeons the case of a patient presenting complications after breast augmentation with an unknown synthetic substance containing methacrylate. Presentation of case A 33-years old Asian woman presented to our Institution with breast deformities, lumps and chest pain. The patient referred previous breast injection “with hospital fat” performed in China six years before. She was not aware about the details of the procedure, and language barriers limited communication. Clinical examination and ultrasounds revealed the irregular distribution of an unknown substance in both breasts. The material was surgically removed and replaced in the same session with polyurethane implants. Chemical analysis revealed the presence of methacrylate. Discussion With a growing demand for non-invasive cosmetic surgery, has been reported a growing population of untrained and unlicensed personnel performing cosmetic surgery in many countries where there are no laws that restrict the use of cosmetic procedures to physicians with appropriate training and with approved materials. Surgical removal of this substances can be extremely challenging and an open procedure with surgical debridement is recommended. Conclusion Breast augmentation with non-absorbable biomaterials can lead to severe complications, in particular for patients intending to breastfeed. PMID:26298244

  10. Functional Human Vascular Network Generated in Photocrosslinkable Gelatin Methacrylate Hydrogels.

    PubMed

    Chen, Ying-Chieh; Lin, Ruei-Zeng; Qi, Hao; Yang, Yunzhi; Bae, Hojae; Melero-Martin, Juan M; Khademhosseini, Ali

    2012-05-23

    The generation of functional, 3D vascular networks is a fundamental prerequisite for the development of many future tissue engineering-based therapies. Current approaches in vascular network bioengineering are largely carried out using natural hydrogels as embedding scaffolds. However, most natural hydrogels present a poor mechanical stability and a suboptimal durability, which are critical limitations that hamper their widespread applicability. The search for improved hydrogels has become a priority in tissue engineering research. Here, the suitability of a photopolymerizable gelatin methacrylate (GelMA) hydrogel to support human progenitor cell-based formation of vascular networks is demonstrated. Using GelMA as the embedding scaffold, it is shown that 3D constructs containing human blood-derived endothelial colony-forming cells (ECFCs) and bone marrow-derived mesenchymal stem cells (MSCs) generate extensive capillary-like networks in vitro. These vascular structures contain distinct lumens that are formed by the fusion of ECFC intracellular vacuoles in a process of vascular morphogenesis. The process of vascular network formation is dependent on the presence of MSCs, which differentiate into perivascular cells occupying abluminal positions within the network. Importantly, it is shown that implantation of cell-laden GelMA hydrogels into immunodeficient mice results in a rapid formation of functional anastomoses between the bioengineered human vascular network and the mouse vasculature. Furthermore, it is shown that the degree of methacrylation of the GelMA can be used to modulate the cellular behavior and the extent of vascular network formation both in vitro and in vivo. These data suggest that GelMA hydrogels can be used for biomedical applications that require the formation of microvascular networks, including the development of complex engineered tissues. PMID:22907987

  11. Functional Human Vascular Network Generated in Photocrosslinkable Gelatin Methacrylate Hydrogels

    PubMed Central

    Chen, Ying-Chieh; Lin, Ruei-Zeng; Qi, Hao; Yang, Yunzhi; Bae, Hojae

    2012-01-01

    The generation of functional, 3D vascular networks is a fundamental prerequisite for the development of many future tissue engineering-based therapies. Current approaches in vascular network bioengineering are largely carried out using natural hydrogels as embedding scaffolds. However, most natural hydrogels present a poor mechanical stability and a suboptimal durability, which are critical limitations that hamper their widespread applicability. The search for improved hydrogels has become a priority in tissue engineering research. Here, the suitability of a photopolymerizable gelatin methacrylate (GelMA) hydrogel to support human progenitor cell-based formation of vascular networks is demonstrated. Using GelMA as the embedding scaffold, it is shown that 3D constructs containing human blood-derived endothelial colony-forming cells (ECFCs) and bone marrow-derived mesenchymal stem cells (MSCs) generate extensive capillary-like networks in vitro. These vascular structures contain distinct lumens that are formed by the fusion of ECFC intracellular vacuoles in a process of vascular morphogenesis. The process of vascular network formation is dependent on the presence of MSCs, which differentiate into perivascular cells occupying abluminal positions within the network. Importantly, it is shown that implantation of cell-laden GelMA hydrogels into immunodeficient mice results in a rapid formation of functional anastomoses between the bioengineered human vascular network and the mouse vasculature. Furthermore, it is shown that the degree of methacrylation of the GelMA can be used to modulate the cellular behavior and the extent of vascular network formation both in vitro and in vivo. These data suggest that GelMA hydrogels can be used for biomedical applications that require the formation of microvascular networks, including the development of complex engineered tissues. PMID:22907987

  12. Synthesis of Methyl Methacrylate From Coal-Derived Syngas

    SciTech Connect

    Ben W.-L. Jang; Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Richard D. Colberg; Samuel S. Tam

    1998-07-27

    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. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is 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(April-June, 1998), RTI has modified the reactor system including a new preheater and new temperature settings for the preheater. Continuous condensation of formaldehyde with propionic acid were carried out over 10% Nb O /SiO at 300°C without 2 5 2 interruption. Five activity and four regeneration cycles have been completed without plugging or material balance problems. The results show that 10% Nb O /SiO deactivates slowly with time 2 5 2 but can be regenerated, at least four times, to 100% of its original activity with 2% O in nitrogen 2 at 400°C. The cycles continue with consistent 90-95% of carbon balance. The reaction is scheduled to complete with 6 activity cycles and 5 regenerations. Used catalysts will be analyzed with TGA and XPS to determine bulk and surface coke content and coke properties. RTI will start the investigation of effects of propionic acid/formaldehyde ratio on reaction activity and product selectivity over 20% Nb O /SiO catalysts.

  13. Synthesis of acrylates and Methacrylates from Coal-Derived Syngas

    SciTech Connect

    1997-05-12

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Federal Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees} C and 180 atm). Bechtel has performed an extensive cost analysis which shows that Eastman`s propionate synthesis step is competitive with other technologies to produce the anhydride. Eastman and Bechtel have also compared the RTI- Eastman-Bechtel three-step methanol route to five other process routes to MMA. The results show that the product MMA can be produced at 520/lb, for a 250 Mlb/year MMA plant, and this product cost is competitive to all other process routes to MMA, except propyne carbonylation. In the second step, RTI and Eastman have developed active and stable V-SI-P tertiary metal oxide catalysts, Nb/Si0{sub 2}, and Ta/Si0{sub 2} catalysts for condensation of propionic anhydride or propionic acid with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst performance. Eastman and Bechtel have used the RTI experimental results of a 20 percent Nb/Si0{sub 2} catalyst, in terms of reactant conversions, MAA selectivities, and MAA yield, for their economic analysis. Recent research focuses on enhancing the condensation reaction yields, a better understanding of the acid-base property correlation and enhancing the catalyst lifetime.

  14. Synthesis and fluorescence properties of divalent europium-poly(methacrylate containing crown ether structure) complexes

    SciTech Connect

    Higashiyama, N.; Nakamura, H.; Mishima, T.; Shiokawa, J.; Adachi, G. )

    1991-02-01

    This paper reports on divalent europium complexes with poly(methacrylate containing crown ether structure)s, poly(crown ether)s, prepared and their fluorescence properties studied. The polymers used were poly(15-crown-5-methyl methacrylate) (PMA15C5), copoly(15- crown-5-methyl methacrylate-X) (copoly(MA15C5-X)); (X = MMA, EMA, BMA, 2-methoxyethyl methacrylate (MAGI) 3,6,9,12,15- pentaoxahexadecyl methacrylate (MAG5)), poly(18-crown-6- methyl methacrylate) (PMA18C6), and copoly(18-crown-6-methyl methacrylate-MMA) (copoly(MA18C6-MMA)), which were obtained by bulk polymerization. The fluorescence properties of Eu{sup 2+} polymers activated by complexing Eu{sup 2+} ions with crown ether groups were measured in powder form. The Eu{sup 2+}-poly (crown ether)s irradiated by UV light generally gave blue bright emission in the region of 420-465 nm. It was Eu{sup 2+}-copoly(Ma15C5-X); (X = MMA, EMA, and MAG1) that showed the largest emission intensity among the Eu{sup 2+} polymers, and its emission intensity was ca. 20% of that for CaWO{sub 4}:Pb (NBS1026) whose quantum efficiency is about 76%. The intensities of emission for the Eu{sup 2+} polymers containing 15-crown-5 were much larger than that for the ones containing 18-crown-6.

  15. Modification of LDPE molecular structure by gamma irradiation for bioapplications

    NASA Astrophysics Data System (ADS)

    Ferreira, L. M.; Falcão, A. N.; Gil, M. H.

    2005-07-01

    The surface properties of low-density polyethylene (LDPE) can be modified by the grafting of 2-hydroxyethyl methacrylate (HEMA). This was done aiming at the production of new materials suitable for bioapplications. Samples with different monomer concentrations were prepared from LDPE particles by gamma irradiation, following different irradiation protocols, including irradiation in presence and absence of air. The samples were characterized by thermal analysis techniques (DSC and TGA) and by Fourier transform infrared spectroscopy (FTIR). The results obtained show a decrease in the crystallinity of the supporting matrix for copolymers with high yields of grafting. However, the new materials prepared maintain good structural order resulting from the protective effect of polyHEMA grafted onto LDPE backbone. These effects can improve the diffusion of other species deeper inside the matrix and increase the material hydrophilicity. The studies performed made possible the selection of experimental protocols adequate for the production of new copolymeric materials with high grafting yield. These were used in the production of new LDPE films with enhanced hydrophilic properties.

  16. Characterization of Lactate Sensors Based on Lactate Oxidase and Palladium Benzoporphyrin Immobilized in Hydrogels.

    PubMed

    Andrus, Liam P; Unruh, Rachel; Wisniewski, Natalie A; McShane, Michael J

    2015-01-01

    An optical biosensor for lactate detection is described. By encapsulating enzyme-phosphor sensing molecules within permeable hydrogel materials, lactate-sensitive emission lifetimes were achieved. The relative amount of monomer was varied to compare three homo- and co-polymer materials: poly(2-hydroxyethyl methacrylate) (pHEMA) and two copolymers of pHEMA and poly(acrylamide) (pAam). Diffusion analysis demonstrated the ability to control lactate transport by varying the hydrogel composition, while having a minimal effect on oxygen diffusion. Sensors displayed the desired dose-variable response to lactate challenges, highlighting the tunable, diffusion-controlled nature of the sensing platform. Short-term repeated exposure tests revealed enhanced stability for sensors comprising hydrogels with acrylamide additives; after an initial "break-in" period, signal retention was 100% for 15 repeated cycles. Finally, because this study describes the modification of a previously developed glucose sensor for lactate analysis, it demonstrates the potential for mix-and-match enzyme-phosphor-hydrogel sensing for use in future multi-analyte sensors. PMID:26198251

  17. In vivo testing of the protection of gloves against acrylates in dentin-bonding systems on patients with known contact allergy to acrylates.

    PubMed

    Andersson, T; Bruze, M; Björkner, B

    1999-11-01

    Occupational contact allergies to dental acrylates are increasing. Commonly used gloves protect poorly against acrylates. The protective efficacy in vivo of other, newer glove materials is not fully known. In this study, an open chamber system was used for testing the protection in vivo of 6 different gloves (1 vinyl glove, 2 latex gloves, 2 nitrile gloves and the 4H glove) against a commonly used dental adhesive, Scotchbond 1, containing 2-hydroxyethyl methacrylate (2-HEMA) and triethylene glycol dimethacrylate (TREGDMA). 8 patients with known contact allergy to 2-HEMA participated. Provocation with 50 microl of the adhesive for 7.5, 15 and 30 min was performed for each glove. The test demonstrated clear differences in the protective efficacy between the gloves. The 4H glove gave by far the best protection, followed by one of the nitrile gloves. One of the latex gloves and the vinyl glove gave a very poor protection against the adhesive. A dose-response relationship was observed between different application times of the acrylate product. The test model promises to be a useful clinical complement to in vitro methods in individual preventive measures against contact sensitization to acrylates. PMID:10554058

  18. Effect of disinfectants containing glutaraldehyde on bonding of a tri-n-butylborane initiated resin to dentine.

    PubMed

    Baba, N; Taira, Y; Matsumura, H; Atsuta, M

    2002-05-01

    The purpose of this study was to evaluate the effects of disinfectants on the bond strength of resin to dentine. The surface of bovine dentine was exposed to formaldehyde (FA) aqueous solutions, glutaraldehyde (GA) aqueous solutions, 2-hydroxyethyl methacrylate aqueous solutions (HEMA), a commercially available dentine primer (Gluma CPS desensitizer, GLUMA), isotonic sodium chloride solution (IS), and distilled water (DW), and placed in a humidor (HU) at 37 degrees C, or non-stored (baseline). All dentine surfaces were conditioned with a 10% citric acid and 3% ferric chloride solution (10-3 liquid), and then bonded to an acrylic rod with a self-curing adhesive resin (Super-Bond C&B). The mean tensile bond strengths determined 24 h after bonding were compared by analysis of variance (ANOVA) and Fisher's protected LSD test (n=5, P < or = 0.05). The exposure of dentine to IS, DW and HU for both 48 and 168 h resulted in a decrease in bond strength when compared with the baseline. The highest bond strengths after 168 h of exposure were obtained with 5% GA, 10% HEMA, and GLUMA, the values of which were equivalent to baseline and were significantly higher than that of FA. It is concluded that disinfectant pre-treatment with 5% GA or GLUMA stabilizes the bonding of tri-n-butylborane (TBB) initiated luting agent to bovine dentine conditioned with 10-3 liquid. PMID:12028497

  19. β-Cyclodextrin hydrogels for the ocular release of antibacterial thiosemicarbazones.

    PubMed

    Glisoni, Romina J; García-Fernández, María J; Pino, Marylú; Gutkind, Gabriel; Moglioni, Albertina G; Alvarez-Lorenzo, Carmen; Concheiro, Angel; Sosnik, Alejandro

    2013-04-01

    Two types of hydrophilic networks with conjugated beta-cyclodextrin (β-CD) were developed with the aim of engineering useful platforms for the localized release of an antimicrobial 5,6-dimethoxy-1-indanone N4-allyl thiosemicarbazone (TSC) in the eye and its potential application in ophthalmic diseases. Poly(2-hydroxyethyl methacrylate) soft contact lenses (SCLs) displaying β-CD, namely pHEMA-co-β-CD, and super-hydrophilic hydrogels (SHHs) of directly cross-linked hydroxypropyl-β-CD were synthesized and characterized regarding their structure (ATR/FT-IR), drug loading capacity, swelling and in vitro release in artificial lacrimal fluid. Incorporation of TSC to the networks was carried out both during polymerization (DP method) and after synthesis (PP method). The first method led to similar drug loads in all the hydrogels, with minor drug loss during the washing steps to remove unreacted monomers, while the second method evidenced the influence of structural parameters on the loading efficiency (proportion of CD units, mesh size, swelling degree). Both systems provided a controlled TSC release for at least two weeks, TSC concentrations (up to 4000μg/g dry hydrogel) being within an optimal therapeutic window for the antimicrobial ocular treatment. Microbiological tests against P. aeruginosa and S. aureus confirmed the ability of TSC-loaded pHEMA-co-β-CD network to inhibit bacterial growth. PMID:23499082

  20. Separation of N-derivatized di- and tri-peptide stereoisomers by micro-liquid chromatography using a quinidine-based monolithic column - Analysis of l-carnosine in dietary supplements.

    PubMed

    Wang, Qiqin; Sánchez-López, Elena; Han, Hai; Wu, Huihui; Zhu, Peijie; Crommen, Jacques; Marina, Maria Luisa; Jiang, Zhengjin

    2016-01-01

    In the present study, a new analytical methodology was developed enabling the enantiomeric determination of N-derivatized di- and tri-peptides in dietary supplements using chiral micro-LC on a monolithic column consisting of poly(O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine-co-2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) (poly(MQD-co-HEMA-co-EDMA)). After optimization of the mobile phase conditions, a baseline resolution of the stereoisomers of 24 out of 53 N-derivatized di- and tri-peptides was obtained. 3,5-Dinitrobenzoyl- and 3,5-dichlorobenzoyl-peptide stereoisomers were separated with exceptionally high selectivity and resolution. The monolithic column was then applied to the quantitative analysis of l-carnosine and its enantiomeric impurity in three different commercial dietary supplements. Method validation demonstrated satisfactory results in terms of linearity, precision, selectivity, accuracy and limits of detection and quantification. The determined amounts of l-carnosine in commercial formulations were in agreement with the labeled content for all analyzed samples, and the enantiomeric impurity was found to be below the limit of detection (LOD), showing the potential of the poly(MQD-co-HEMA-co-EDMA) monolithic column as a reliable tool for the quality control of l-carnosine in dietary supplements by micro-LC. PMID:26410182

  1. Characterization of Lactate Sensors Based on Lactate Oxidase and Palladium Benzoporphyrin Immobilized in Hydrogels

    PubMed Central

    Andrus, Liam P.; Unruh, Rachel; Wisniewski, Natalie A.; McShane, Michael J.

    2015-01-01

    An optical biosensor for lactate detection is described. By encapsulating enzyme-phosphor sensing molecules within permeable hydrogel materials, lactate-sensitive emission lifetimes were achieved. The relative amount of monomer was varied to compare three homo- and co-polymer materials: poly(2-hydroxyethyl methacrylate) (pHEMA) and two copolymers of pHEMA and poly(acrylamide) (pAam). Diffusion analysis demonstrated the ability to control lactate transport by varying the hydrogel composition, while having a minimal effect on oxygen diffusion. Sensors displayed the desired dose-variable response to lactate challenges, highlighting the tunable, diffusion-controlled nature of the sensing platform. Short-term repeated exposure tests revealed enhanced stability for sensors comprising hydrogels with acrylamide additives; after an initial “break-in” period, signal retention was 100% for 15 repeated cycles. Finally, because this study describes the modification of a previously developed glucose sensor for lactate analysis, it demonstrates the potential for mix-and-match enzyme-phosphor-hydrogel sensing for use in future multi-analyte sensors. PMID:26198251

  2. Spectroscopic Analysis of Nd^3+:Y2O3 Nanocrystals in Polymers and Copolymers

    NASA Astrophysics Data System (ADS)

    Ray, Nathan; Nash, Kelly; Dennis, Robert; Gruber, John; Sardar, Dhiraj; Gen Zhang, Mao

    2009-04-01

    Spectroscopic properties of nanocrystalline Nd^3+ in Nd^3+:Y2O3 embedded in solid plastic hosts (2-hydroxyethyl methacrylate (HEMA) and copolymer of HEMA/styrene) are characterized. The standard Judd-Ofelt model has been applied to the room temperature absorption intensities of Nd^3+(4f^3) transitions in the plastic hosts to determine the three phenomenological intensity parameters: φ2, φ4, and φ6. Intensity parameters are then utilized to determine the radiative decay rates and branching ratios of the Nd^3+(4f^ 3) transitions from the upper manifold state ^4F3/2 to the lower-lying multiplet manifolds ^4IJ (J= 9/2, 11/2, 13/2, 15/2). Emission cross sections and room temperature fluorescence lifetimes of the important intermanifold ^4F3/2->^4IJ (J=9/2, 11/2, 13/2)transitions are determined. We investigate the detailed crystal-field splitting of the energy levels of the Nd^3+ ion in the Y2O3/polymer host. The 300 K spectraare analyzed for the energy level transitions between the ^2S+1LJ multiplet manifolds of Nd^3+(4f^3). Results are also compared with a crystal-field splitting analysis reported earlier for single-crystal Nd^3+:Y2O3.

  3. Development of molecular imprinted nanosensor for determination of tobramycin in pharmaceuticals and foods.

    PubMed

    Yola, Mehmet Lütfi; Uzun, Lokman; Özaltın, Nuran; Denizli, Adil

    2014-03-01

    In this study, we developed quartz crystal microbalance (QCM) nanosensor for the real-time detection of tobramycin (TOB). Firstly, the modification of gold surface of QCM chip was performed by self-assembling monolayer formation of allyl mercaptane to introduce polymerizable double bonds on the chip surface. Then, TOB imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoglutamic acid) [p(HEMA-MAGA)] film was generated on the gold surface. The nonmodified and TOB-imprinted p(HEMA-MAGA) surfaces were characterized by using atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, ellipsometry and contact angle measurements. The proposed method was validated according to the ICH guideline. The linearity range and the detection limit (S/N=3) were obtained as 1.7×10(-11)-1.5×10(-10) M and 5.7×10(-12) M, respectively. The developed method was applied to pharmaceuticals, and food samples such as chicken egg white and milk extract for the determination of TOB. In addition, association kinetics analysis and isotherm models were applied to the data to explain the adsorption process that took place. PMID:24468376

  4. Imprinted Contact Lenses for Sustained Release of Polymyxin B and Related Antimicrobial Peptides.

    PubMed

    Malakooti, Negin; Alexander, Cameron; Alvarez-Lorenzo, Carmen

    2015-10-01

    The aim of this work was to develop drug-soft contact lens combination products suitable for controlled release of antimicrobial peptides on the ocular surface. Incorporation of functional monomers and the application of molecular imprinting techniques were explored to endow 2-hydroxyethyl methacrylate (HEMA) hydrogels with the ability to load and to sustain the release of polymyxin B and vancomycin. Various HEMA-drug-functional monomer-cross-linker molar ratios were evaluated to prepare polymyxin B imprinted and non-imprinted hydrogels. Acrylic acid-functionalized and imprinted hydrogels loaded greater amounts of polymyxin B and led to more sustained release profiles, in comparison with non-functionalized and non-imprinted networks. Polymyxin B-loaded hydrogels showed good biocompatibility in hen's egg test-chorioallantoic membrane tests. Functionalized hydrogels also loaded vancomycin and sustained its release, but the imprinting effect was only exhibited with polymyxin B, as demonstrated in rebinding tests. Microbiological assays carried out with Pseudomonas aeruginosa allowed identification of the most suitable hydrogel composition for efficient bacteria eradication; some hydrogels being able to stand several continued challenges against this important bacterial pathogen. PMID:26094884

  5. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization.

    PubMed

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao

    2014-12-10

    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  6. Polymerization Behavior of Hydrophilic-Rich Phase of Dentin Adhesive

    PubMed Central

    Abedin, F.; Parthasarathy, R.; Misra, A.; Spencer, P.

    2015-01-01

    The 2-fold objectives of this study were 1) to understand whether model hydrophobic- and hydrophilic-rich phase mimics of dentin adhesive polymerize similarly and 2) to determine which factor, the dimethacrylate component, bisphenol A glycerolate dimethacrylate (BisGMA) or photoinitiator concentration, has greater influence on the polymerization of the hydrophilic-rich phase mimic. Current dentin adhesives are sensitive to moisture, as evidenced by nanoleakage in the hybrid layer and phase separation into hydrophobic- and hydrophilic-rich phases. Phase separation leads to limited availability of the cross-linkable dimethacrylate monomer and hydrophobic photoinitiators within the hydrophilic-rich phase. Model hydrophobic-rich phase was prepared as a single-phase solution by adding maximum wt% deuterium oxide (D2O) to HEMA/BisGMA neat resins containing 45 wt% 2-hydroxyethyl methacrylate (HEMA). Mimics of the hydrophilic-rich phase were prepared similarly but using HEMA/BisGMA neat resins containing 95, 99, 99.5, and 100 wt% HEMA. The hydrophilic-rich mimics were prepared with standard or reduced photoinitiator content. The photoinitiator systems were camphorquinone (CQ)/ethyl 4-(dimethylamino)benzoate (EDMAB) with or without [3-(3, 4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethylammonium chloride (QTX). The polymerization kinetics was monitored using a Fourier transform infrared spectrophotometer with a time-resolved collection mode. The hydrophobic-rich phase exhibited a significantly higher polymerization rate compared with the hydrophilic-rich phase. Postpolymerization resulting in the secondary rate maxima was observed for the hydrophilic-rich mimic. The hydrophilic-rich mimics with standard photoinitiator concentration but varying cross-linker (BisGMA) content showed postpolymerization and a substantial degree of conversion. In contrast, the corresponding formulations with reduced photoinitiator concentrations exhibited lower polymerization and

  7. Polymerization behavior of hydrophilic-rich phase of dentin adhesive.

    PubMed

    Abedin, F; Ye, Q; Parthasarathy, R; Misra, A; Spencer, P

    2015-03-01

    The 2-fold objectives of this study were 1) to understand whether model hydrophobic- and hydrophilic-rich phase mimics of dentin adhesive polymerize similarly and 2) to determine which factor, the dimethacrylate component, bisphenol A glycerolate dimethacrylate (BisGMA) or photoinitiator concentration, has greater influence on the polymerization of the hydrophilic-rich phase mimic. Current dentin adhesives are sensitive to moisture, as evidenced by nanoleakage in the hybrid layer and phase separation into hydrophobic- and hydrophilic-rich phases. Phase separation leads to limited availability of the cross-linkable dimethacrylate monomer and hydrophobic photoinitiators within the hydrophilic-rich phase. Model hydrophobic-rich phase was prepared as a single-phase solution by adding maximum wt% deuterium oxide (D2O) to HEMA/BisGMA neat resins containing 45 wt% 2-hydroxyethyl methacrylate (HEMA). Mimics of the hydrophilic-rich phase were prepared similarly but using HEMA/BisGMA neat resins containing 95, 99, 99.5, and 100 wt% HEMA. The hydrophilic-rich mimics were prepared with standard or reduced photoinitiator content. The photoinitiator systems were camphorquinone (CQ)/ethyl 4-(dimethylamino)benzoate (EDMAB) with or without [3-(3, 4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-2-hydroxypropyl]trimethylammonium chloride (QTX). The polymerization kinetics was monitored using a Fourier transform infrared spectrophotometer with a time-resolved collection mode. The hydrophobic-rich phase exhibited a significantly higher polymerization rate compared with the hydrophilic-rich phase. Postpolymerization resulting in the secondary rate maxima was observed for the hydrophilic-rich mimic. The hydrophilic-rich mimics with standard photoinitiator concentration but varying cross-linker (BisGMA) content showed postpolymerization and a substantial degree of conversion. In contrast, the corresponding formulations with reduced photoinitiator concentrations exhibited lower polymerization and

  8. Novel catalysts for the environmentally friendly synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.

    1997-11-01

    The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) to form MMA. The first two steps, propionic acid synthesis and condensation, are discussed here. The low-temperature, low-pressure process for single-step hydrocarbonylation of ethylene to propionic acid is carried out using a homogeneous iodine-promoted Mo(CO){sub 6} catalyst at pressures (30--70 atm) and temperatures (150--200 C) lower than those reported for other catalysts. Mechanistic investigations suggest that catalysis is initiated by a rate-limiting CO dissociation from Mo(CO){sub 6}. This dissociation appears to be followed by an inner electron-transfer process of an I atom from EtI to the coordinately unsaturated Mo(CO){sub 5}. This homogeneous catalyst for propionate synthesis represents the first case of an efficient carbonylation process based on Cr group metals. The condensation of formaldehyde with propionic acid is carried out by acid-base bifunctional catalysts. As a result of screening over 80 catalytic materials, group V metals supported on an amorphous silica are found to be most effective. A 20% Nb/SiO{sub 2} catalyst appears to be the most active and stable catalyst thus far. Preliminary relations among the reaction yield and catalyst properties indicate that a high surface area and a low overall surface acidity (<50 = mol of NH{sub 3}/g), with a high proportion of the acidity being weak (<350 C desorption of NH{sub 3}), are desirable. Long-term deactivation of V-Si-P, Nb-Si, and Ta-Si catalysts suggests that carbon deposition is the primary cause for activity decay, and the catalyst activity is partially restorable by oxidative regeneration.

  9. 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

    1999-07-19

    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. During the April-June quarter(04-06/99) the first in-situ formaldehyde generation from DME and condensation with methyl propionate is demonstrated and the results are summarized. The supported niobium catalyst shows better condensation activity, but supported tungsten catalyst has higher formaldehyde selectivity. The project team has also completed a 200-hour long term test of PA-HCHO condensation over 30% Nb{sub 2}O{sub 5}/SiO{sub 2}. Three activity cycles and two regeneration cycles were carried out. 30% Nb{sub 2}O{sub 5}/SiO{sub 2} showed similar MAA yields as 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. However, the deactivation appears to be slower with 30% Nb{sub 2}O{sub 5}/SiO{sub 2} than 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. An detailed economic analysis of PA-HCHO condensation process for a 250 million lb/yr MMA plant is currently studied by Bechtel. Using the Amoco data-based azeotropic distillation model as the basis, an ASPEN flow sheet model was constructed to simulate the formaldehyde and propionic acid condensation processing section based on RTI's design data. The RTI MAA effluent azeotropic distillation column was found to be much more difficult to converge. The presence of non-condensible gases along with the byproduct DEK (both of which were not presented in

  10. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG

    1998-10-20

    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. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is 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 (July-September, 1998), the project team has completed the continuous condensation of formaldehyde with propionic acid over 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. Six activity and five regeneration cycles have been completed. The results show that 10% Nb{sub 2}O{sub 5}/SiO{sub 2} deactivates slowly with time but can be regenerated to its original activity with 2% O{sub 2} in nitrogen over night at 400 C. We have investigated the effects of regeneration, propionic acid/formaldehyde ratio (PA/HCHO = 4.5/1 to 1.5/1) and reaction temperature(280-300 C) on reaction activity and product selectivity over 20% Nb{sub 2}O{sub 5}/SiO{sub 2} catalysts. The regeneration effect on 20% Nb{sub 2}O{sub 5}/SiO{sub 2} is similar to the effect on 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. The regeneration can bring the deactivated catalyst to its original activity. However, the selectivity to MAA decreases with regeneration while the selectivity to DEK and CO{sub 2} increases. When PA/HCHO ratio is decreased from 4.5/1 to 2.25/1 then to 1.5/1 at 300 C the MAA yield decreases but the MAA selectivity first increases then decreases. Decreasing the reaction temperature from 300 C to 280 C decreases the MAA yield from 39.5% to 30.7% but increases the MAA selectivity from 73.7% to 82.2%. The

  11. Synthesis of Acrylates and Methacrylates from Coal-Derived Syngas.

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.; Tam, S.S.

    1997-10-17

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy/Federal Energy Technology Center (DOE/FETC). This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Over the last quarter, RTI carried out activity tests on a pure (99 percent) Nb{sub 2}O{sub 5} catalyst, received from Alfa Aesar, under the following experimental conditions: T=300 C; P=4 atm, 72:38:16:4:220 mmol/h, PA:H{sub 2}0:HCHO:CH{sub 3}0H:N{sub 2}; 5-g catalyst charge. For the pure material, the MAA yields (based on HCHO and PA) were at 8.8 and 1.5 percent, clearly inferior compared to those for a 10-percent Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst (20.1 and 4.5 percent). The X-ray diffraction (XRD) patterns of pure Nb{sub 2}O{sub 5} and 20-percent Nb{sub 2}O{sub 5}/Si0{sub 2} that while pure Nb{sub 2}O{sub 5} is very highly crystalline, Si0{sub 2} support for an amorphous nature of the 20 percent Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst the last quarter, RTI also began research on the use of dimethyl ether (DME), product of methanol dehydrocondensation, as an alternate feedstock in MMA synthesis. As a result, formaldehyde is generated either externally or in situ, from DME, in the process envisaged in the contract extension. The initial work on the DME extension of the contract focuses on a tradeoff analysis that will include a preliminary economic analysis of the DME and formaldehyde routes and catalyst synthesis and testing for DME partial oxidation and condensation reactions. Literature guides exist for DME partial oxidation catalysts; however, there are no precedent studies on catalyst development for DME-methyl propionate (MP) condensation reactions, thereby making DME-MP reaction studies a

  12. Tissue reaction to methyl methacrylate monomer. A comparative study in the rabbit's ear on the toxicity of methyl methacrylate monomer of varying composition.

    PubMed

    Linder, L

    1976-02-01

    The aim of the present investigation was to evaluate if a bone cement monomer with a high concentration of accelerator (N,N-dimethyl-p-toluidine) is more toxic than a methyl methacrylate monomer, free from accelerator. 1) No difference in the acute local toxicity between CMW, Simplex-P and pure methyl methacrylate monomer was seen. 2) By gas chromatography. N,N-dimethyl-p-toluidine was shown to be water soluble to a small extent. Any bone cement monomer in current use can be fully dissolved in saline to a concentration of about 1 per cent. PMID:1266590

  13. Preparation of Light-responsive Membranes by a Combined Surface Grafting and Postmodification Process

    PubMed Central

    Schöller, Katrin; Baumann, Lukas; Hegemann, Dirk; De Courten, Damien; Wolf, Martin; Rossi, René M.; Scherer, Lukas J.

    2014-01-01

    In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface. For example, the influence of the plasma-treatment on different types of membranes (e.g. polyester, polycarbonate, polyvinylidene fluoride) is studied. Furthermore, the time-dependent stability of the surface-grafted membranes is shown by contact angle measurements. When grafting poly(2-hydroxyethyl methacrylate) (PHEMA) in this way, the surface can be further modified by esterification of the alcohol moiety of the polymer with a carboxylic acid function of the desired substance. These reactions can therefore be used for the functionalization of the membrane surface. For example, the surface tension of the membrane can be changed or a desired functionality as the presented light-responsiveness can be inserted. This is demonstrated by reacting PHEMA with a carboxylic acid functionalized spirobenzopyran unit which leads to a light-responsive membrane. The choice of solvent plays a major role in the postmodification step and is discussed in more detail in this paper. The permeability measurements of such functionalized membranes are performed using a Franz cell with an external light source. By changing the wavelength of the light from the visible to the UV-range, a change of permeability of aqueous caffeine solutions is observed. PMID:24686898

  14. Preparation of light-responsive membranes by a combined surface grafting and postmodification process.

    PubMed

    Schöller, Katrin; Baumann, Lukas; Hegemann, Dirk; De Courten, Damien; Wolf, Martin; Rossi, René M; Scherer, Lukas J

    2014-01-01

    In order to modify the surface tension of commercial available track-edged polymer membranes, a procedure of surface-initiated polymerization is presented. The polymerization from the membrane surface is induced by plasma treatment of the membrane, followed by reacting the membrane surface with a methanolic solution of 2-hydroxyethyl methacrylate (HEMA). Special attention is given to the process parameters for the plasma treatment prior to the polymerization on the surface. For example, the influence of the plasma-treatment on different types of membranes (e.g. polyester, polycarbonate, polyvinylidene fluoride) is studied. Furthermore, the time-dependent stability of the surface-grafted membranes is shown by contact angle measurements. When grafting poly(2-hydroxyethyl methacrylate) (PHEMA) in this way, the surface can be further modified by esterification of the alcohol moiety of the polymer with a carboxylic acid function of the desired substance. These reactions can therefore be used for the functionalization of the membrane surface. For example, the surface tension of the membrane can be changed or a desired functionality as the presented light-responsiveness can be inserted. This is demonstrated by reacting PHEMA with a carboxylic acid functionalized spirobenzopyran unit which leads to a light-responsive membrane. The choice of solvent plays a major role in the postmodification step and is discussed in more detail in this paper. The permeability measurements of such functionalized membranes are performed using a Franz cell with an external light source. By changing the wavelength of the light from the visible to the UV-range, a change of permeability of aqueous caffeine solutions is observed. PMID:24686898

  15. Adsorption of paraquat using methacrylic acid-modified rice husk.

    PubMed

    Hsu, Shih-Tong; Pan, Ting-Chung

    2007-12-01

    This work investigates the adsorption of paraquat from aqueous medium using a methacrylic acid (MAA)-modified rice husk. The carboxyl groups were chemically bound to the surface of the rice husk by graft copolymerization using Fenton's reagent as a redox initiator. The graft copolymerization was examined to determine the H(2)O(2) concentration and the amount of MAA monomer used. FT-IR spectra confirmed the presence of carbonyl groups on the structural units of the rice husk derivative. The MAA-modified rice husks were hydrolyzed to sodium salt and used to adsorb paraquat. The adsorption was rapid in the first few minutes and quickly reached equilibrium. Equilibrium adsorption data are more consistent with the Langmuir isotherm equation than with the Freundlich equation. The maximum adsorption capacity of modified rice husks was 317.7mg/g-adsorbent. This value clearly exceeds the 60mg/g of Fuller's earth and the 90mg/g of activated carbon, which are the most commonly used binding agents for paraquat. PMID:17303413

  16. Directed endothelial cell morphogenesis in micropatterned gelatin methacrylate hydrogels.

    PubMed

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2012-12-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50-150 μm height). We demonstrated the significant dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 μm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs. PMID:23018132

  17. Directed Endothelial Cell Morphogenesis in Micropatterned Gelatin Methacrylate Hydrogels

    PubMed Central

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2013-01-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50–150 µm height). We demonstrated the significance dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 µm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs. PMID:23018132

  18. Control of cell adhesion on poly(methyl methacrylate).

    PubMed

    Patel, Shyam; Thakar, Rahul G; Wong, Josh; McLeod, Stephen D; Li, Song

    2006-05-01

    Keratoprostheses have been constructed from a wide variety of transparent materials, including poly(methyl methacrylate) (PMMA). However, the success of keratoprosthesis has been plagued by numerous shortcomings that include the weakening of the implant-host interface due to weak cell adhesion and opaque fibrous membrane formation over the inner surface of the implant due to fibroblast attachment. An effective solution requires a surface modification that would selectively allow enhanced cell attachment at the implant-host interface and reduced cell attachment over the interior surface of the implant. Here, we have developed a novel and simple peptide conjugation scheme to modify PMMA surfaces, which allowed for region-specific control of cell adhesion. This method uses di-amino-PEG, which can be grafted onto PMMA using hydrolysis or aminolysis method. PEG can resist cell adhesion and protein adsorption. The functionalization of grafted di-amino-PEG molecules with RGD peptide not only restored cell adhesion to the surfaces, but also enhanced cell attachment and spreading as compared to untreated PMMA surfaces. Long-term cell migration and micropatterning studies clearly indicated that PEG-PMMA surfaces with and without RGD conjugation can be used to differentiate cell adhesion and control cell attachment spatially on PMMA, which will have potential applications in the modification of keratoprostheses. PMID:16439014

  19. Methyl methacrylate and respiratory sensitization: A Critical review

    PubMed Central

    Borak, Jonathan; Fields, Cheryl; Andrews, Larry S; Pemberton, Mark A

    2011-01-01

    Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants.The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer. PMID:21401327

  20. Purification of large plasmids with methacrylate monolithic columns.

    PubMed

    Krajnc, Nika Lendero; Smrekar, Franci; Cerne, Jasmina; Raspor, Peter; Modic, Martina; Krgovic, Danijela; Strancar, Ales; Podgornik, Ales

    2009-08-01

    The rapid evolution of gene therapy and DNA vaccines results in an increasing interest in producing large quantities of pharmaceutical grade plasmid DNA. Most current clinical trials involve plasmids of 10 kb or smaller in size, however, future requirements for multigene vectors including extensive control regions may require the production of larger plasmids, e. g., 20 kb and bigger. The objective of this study was to examine certain process conditions for purification of large plasmids with the size of up to 93 kb. Since there is a lack of knowledge about production and purification of bigger plasmid DNA, cell lysis and storage conditions were investigated. The impact of chromatographic system and methacrylate monolithic column on the degradation of plasmid molecules under nonbinding conditions at different flow rates was studied. Furthermore, capacity measurements varying salt concentration in loading buffer were performed and the capacities up to 13 mg of plasmid per mL of the monolithic column were obtained. The capacity flow independence in the range from 130 to 370 cm/h was observed. Using high resolution monolithic column the separation of linear and supercoiled isoforms of large plasmids was obtained. Last but not least, since the baseline separation of RNA and pDNA was achieved, the one step purification on larger CIM DEAE 8 mL tube monolithic column was performed and the fractions were analyzed by CIM analytical monolithic columns. PMID:19598166

  1. IR laser ablation of doped poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Gaspard, S.; Oujja, M.; Rebollar, E.; Walczak, M.; Díaz, L.; Santos, M.; Castillejo, M.

    2007-05-01

    We investigate the TEA CO 2 laser ablation of films of poly(methyl methacrylate), PMMA, with average MW 2.5, 120 and 996 kDa doped with photosensitive compounds iodo-naphthalene (NapI) and iodo-phenanthrene (PhenI) by examining the induced morphological and physicochemical modifications. The films casted on CaF 2 substrates were irradiated with a pulsed CO 2 laser (10P(20) line at 10.59 μm) in resonance with vibrational modes of PMMA and of the dopants at fluences up to 6 J/cm 2. Laser induced fluorescence probing of photoproducts in a pump and probe configuration is carried out at 266 nm. Formation of naphthalene (NapH) and phenanthrene (PhenH) is observed in NapI and PhenI doped PMMA, respectively, with relatively higher yields in high MW polymer, in similarity with results obtained previously upon irradiation in the UV at 248 nm. Above threshold, formation of photoproducts is nearly complete after 200 ms. As established via optical microscopy, bubbles are formed in the irradiated areas with sizes that depend on polymer MW and filaments are observed to be ejected out of the irradiated volume in the samples made with high MW polymer. The implications of these results for the mechanisms of polymer IR laser ablation are discussed and compared with UV range studies.

  2. Characterization of methacrylate chromatographic monoliths bearing affinity ligands.

    PubMed

    Černigoj, Urh; Vidic, Urška; Nemec, Blaž; Gašperšič, Jernej; Vidič, Jana; Lendero Krajnc, Nika; Štrancar, Aleš; Podgornik, Aleš

    2016-09-16

    We investigated effect of immobilization procedure and monolith structure on chromatographic performance of methacrylate monoliths bearing affinity ligands. Monoliths of different pore size and various affinity ligands were prepared and characterized using physical and chromatographic methods. When testing protein A monoliths with different protein A ligand densities, a significant nonlinear effect of ligand density on dynamic binding capacity (DBC) for IgG was obtained and accurately described by Langmuir isotherm curve enabling estimation of protein A utilization as a function of ligand density. Maximal IgG binding capacity was found to be at least 12mg/mL exceeding theoretical monolayer adsorption value of 7.8mg/mL assuming hexagonal packing and IgG hydrodynamic diameter of 11nm. Observed discrepancy was explained by shrinkage of IgG during adsorption on protein A experimentally determined through calculated adsorbed IgG layer thickness of 5.4nm from pressure drop data. For monoliths with different pore size maximal immobilized densities of protein A as well as IgG dynamic capacity linearly correlates with monolith surface area indicating constant ligand utilization. Finally, IgGs toward different plasma proteins were immobilized via the hydrazide coupling chemistry to provide oriented immobilization. DBC was found to be flow independent and was increasing with the size of bound protein. Despite DBC was lower than IgG capacity to immobilized protein A, ligand utilization was higher. PMID:27554023

  3. Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification.

    PubMed

    Bux, Jaiyana; Manga, Mohamed S; Hunter, Timothy N; Biggs, Simon

    2016-07-28

    Accurate control of particle size at relatively narrow polydispersity remains a key challenge in the production of synthetic polymer particles at scale. A cross-flow membrane emulsification (XME) technique was used here in the preparation of poly(methyl methacrylate) microspheres at a 1-10 l h(-1) scale, to demonstrate its application for such a manufacturing challenge. XME technology has previously been shown to provide good control over emulsion droplet sizes with careful choice of the operating conditions. We demonstrate here that, for an appropriate formulation, equivalent control can be gained for a precursor emulsion in a batch suspension polymerization process. We report here the influence of key parameters on the emulsification process; we also demonstrate the close correlation in size between the precursor emulsion and the final polymer particles. Two types of polymer particle were produced in this work: a solid microsphere and an oil-filled matrix microcapsule.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'. PMID:27298430

  4. Nonsolvents-induced swelling of poly(methyl methacrylate) nanoparticles.

    PubMed

    Shundo, Atsuomi; Hori, Koichiro; Penaloza, David P; Yoshihiro, Kazuki; Annaka, Masahiko; Tanaka, Keiji

    2013-10-21

    Polymer nanoparticles have been used in a wide variety of applications. In most of these applications, they are generally dispersed in a non-solvent. However, the effect of the non-solvent on the structure, physical properties and function of the nanoparticles has not yet ever taken into account. In this study, monodispersed poly(methyl methacrylate) (PMMA) nanoparticles were prepared by a surfactant-free emulsion polymerization. The PMMA nanoparticles were dispersed in water and in methanol, both typical non-solvents for PMMA, so that we could discuss the effect of the non-solvent on the nanoparticles. Dynamic light scattering measurements revealed that the hydrodynamic radius of the PMMA nanoparticles in methanol was larger than the same PMMA dispersed in water. Their DLS values were also larger than the radius of the nanoparticles measured by atomic force microscopy. When pyrene was dispersed in methanol with the PMMA nanoparticles, it was incorporated into the nanoparticles. These results clearly indicate that non-solvent molecules can be sorbed into polymer nanoparticles because the area of the interface, where polymer segments might be dissolved into liquid phases, as the total volume is quite larger for such nanoparticles. Therefore, based on our findings, it can be arguably established that the present assumption for a polymer not to be swollen in its non-solvent is not necessarily true. PMID:23955567

  5. Well-defined inorganic/organic nanocomposite by nano silica core-poly(methyl methacrylate/butylacrylate/trifluoroethyl methacrylate) shell.

    PubMed

    Chang, Gang; He, Ling; Zheng, Wei; Pan, Aizhao; Liu, Jing; Li, Yingjun; Cao, Ruijun

    2013-04-15

    The novel inorganic/organic core-shell SiO2/P(MMA/BA/3FMA) nanocomposite for coating application is synthesized in this paper by seed emulsion polymerization, in which the inorganic phase is composed of nano-SiO2 modified by vinyl-trimethoxysilane (VMS) or γ-methacryloxy propyl trimethoxylsilane (MPMS), and the organic phase is made of terpolymer by 2,2,2-trifluoroethyl methacrylate (3FMA), methyl methacrylate (MMA), and n-butyl acrylate (BA). The chemical structure of SiO2/P(MMA/BA/3FMA) is characterized by FTIR. The effect of surfactant polyvinylpyrrolidone (PVP), sodium dodecyl sulfate (SDS)/octyl phenyl polyoxyethylene ether (TX-10), sodium dodecyl benzene sulfonate (SDBS)/TX-10 and sodium hexametaphosphate (SHMP) on the grafting ratio (GR) of VMS and MPMS, the dispersion of nano-SiO2 particles and the film properties of SiO2/P(MMA/BA/3FMA) are investigated by TGA, DLS, TEM, SEM, and XPS. The morphology variation and the particle size distributions of SiO2/P(MMA/BA/3FMA) with the content of surfactant and P(MMA/BA/3FMA) are characterized. It is found that MPMS is more effective than VMS in improving GR and the dispersion of nano-SiO2 particles. The surfactants are favor of gaining the higher GR in the multilayer grafted nano-SiO2, especially SDS/TX-10 for 17.6% GR. The morphology of SiO2/P(MMA/BA/3FMA) is controlled by the amount of SDS/TX-10 and P(MMA/BA/3FMA) as the core-shell particles, the stacked pomegranate seed with multicore and the multicore-single shell structure when w(MMA)/w(BA)/w(3FMA)=1.3/1/1. Among the different surfactants, SDBS/TX-10 and PVP could give the monodispersing nano-SiO2 in the terpolymer matrix of the films, but SDS/TX-10 and SDBS/TX-10 could perform the fluorine-rich surface. PMID:23403111

  6. Surface modification of silk fibroin fibers with poly(methyl methacrylate) and poly(tributylsilyl methacrylate) via RAFT polymerization for marine antifouling applications.

    PubMed

    Buga, Mihaela-Ramona; Zaharia, Cătălin; Bălan, Mihai; Bressy, Christine; Ziarelli, Fabio; Margaillan, André

    2015-06-01

    In this study, silk fibroin surface containing hydroxyl and aminogroups was firstly modified using a polymerizable coupling agent 3-(trimethoxysilyl) propyl methacrylate (MPS), in order to induce vinyl groups onto the fiber surface. The reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization of methyl methacrylate (MMA) and tributylsilyl methacrylate (TBSiMA) through the immobilized vinyl bond on the silk fibroin surface in the presence of 2-cyanoprop-2-yl dithiobenzoate (CPDB) as chain-transfer agent and 2,2'-azobis(isobutyronitrile) (AIBN) as initiator was conducted in toluene solution at 70°C for 24h. The structure and properties of the modified fiber were characterized by Fourier Transform Infrared Spectroscopy, (13)C, (29)Si Nuclear Magnetic Resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), confirming the presence of the coupling molecule and the methacrylate groups onto the silk fibroin fiber surface. Molecular weight distributions were assessed by triple detection size exclusion chromatography (TD-SEC) in order to verify the livingness of the polymerization. PMID:25842130

  7. Synthesis of three different galactose-based methacrylate monomers for the production of sugar-based polymers.

    PubMed

    Desport, Jessica S; Mantione, Daniele; Moreno, Mónica; Sardón, Haritz; Barandiaran, María J; Mecerreyes, David

    2016-09-01

    Glycopolymers, synthetic sugar-containing macromolecules, are attracting ever-increasing interest from the chemistry community. Glycidyl methacrylate (GMA) is an important building block for the synthesis of sugar based methacrylate monomers and polymers. Normally, glycidyl methacrylate shows some advantages such as reactivity against nucleophiles or milder synthetic conditions such as other reactive methacrylate monomers. However, condensation reactions of glycidyl methacrylate with for instance protected galactose monomer leads to a mixture of two products due to a strong competition between the two possible pathways: epoxide ring opening or transesterification. In this paper, we propose two alternative routes to synthesize regiospecific galactose-based methacrylate monomers using the epoxy-ring opening reaction. In the first alternative route, the protected galactose is first oxidized to the acid in order to make it more reactive against the epoxide of GMA. In the second route, the protected sugar was first treated with epichlorohydrin followed by the epoxy ring opening reaction with methacrylic acid, to create an identical analogue of the ring-opening product of GMA. These two monomers were polymerized using conventional radical polymerization and were compared to the previously known galactose-methacrylate one. The new polymers show similar thermal stability but lower glass transition temperature (Tg) with respect to the known galactose methacrylate polymer. PMID:27394038

  8. SOLUTION RHEOLOGY OF HYPERBRANCHED POLYESTERS AND THEIR BLENDS WITH LINEAR POLYMERS

    EPA Science Inventory

    In this study, the rheological properties of different generations of hyperbranched polyesters in 1-methyl-2-pyrrolidinone solvent and their blends with poly(2-hydroxyethyl methacrylate) have ben investigated. All the hyperbranched polyester solutions exhibited Newtonian behavior...

  9. Can quaternary ammonium methacrylates inhibit matrix MMPs and cathepsins?

    PubMed Central

    Tezvergil-Mutluay, Arzu; Agee, Kelli A.; Mazzoni, Annalisa; Carvalho, Ricardo M.; Carrilho, Marcela; Tersariol, Ivarne L.; Nascimento, Fabio D.; Imazato, Satoshi; Tjäderhane, Leo; Breschi, Lorenzo; Tay, Franklin R; Pashley, David H.

    2014-01-01

    Objective Dentin matrices release ICTP and CTX fragments during collagen degradation. ICTP fragments are known to be produced by MMPs. CTX fragments are thought to come from cathepsin K activity. The purpose of this study was to determine if quaternary methacrylates (QAMs) can inhibit matrix MMPs and cathepsins. Methods Dentin beams were demineralizated, and dried to constant weight. Beams were incubated with rh-cathepsin B, K, L or S for 24 h at pH 7.4 to identify which cathepsins release CTX at neutral pH. Beams were dipped in ATA, an antimicrobial QAM to determine if it can inhibit dentin matrix proteases. Other beams were dipped in another QAM (MDPB) to determine if it produced similar inhibition of dentin proteases. Results Only beams incubated with cathepsin K lost more dry mass than the controls and released CTX. Dentin beams dipped in ATA and incubated for 1 week at pH 7.4, showed a concentration-dependent reduction in weight-loss. There was no change in ICTP release from control values, meaning that ATA did not inhibit MMPs. Media concentrations of CTX fell significantly at 15 wt% ATA indicating that ATA inhibits capthesins. Beams dipped in increasing concentrations of MDPB lost progressively less mass, showing that MDPB is a protease-inhibitor. ICTP released from controls or beams exposed to low concentrations were the same, while 5 or 10% MDPB significantly lowered ICTP production. CTX levels were strongly inhibited by 2.5–10% MDPB, indicating that MDPB is a potent inhibitor of both MMPs and cathepsin K. Significance CTX seems to be released from dentin matrix only by cathepsin K. MMPs and cathepsin K and B may all contribute to matrix degradation. PMID:25467953

  10. LG4-5 domains of laminin-2 binds α-dystroglycan to allow myotube attachment and prevent anoikis

    PubMed Central

    Munoz, Jesus; Zhou, YanWen; Jarrett, Harry W.

    2010-01-01

    Poly(2-hydroxyethyl methacrylate) (PolyHEMA) prevents cell attachment was used here to study anoikis, the process where cells die when unattached or attached to an inappropriate matrix, in mouse C2C12 myotubes. A method was developed to efficiently embed proteins into PolyHEMA and the effect on cultured myotubes was determined. Myotubes grown on PolyHEMA-coated plates fail to attach to the surface and remain as rounded, suspended cells, undergo dramatic increases in apoptosis and necrosis, and the number of viable cells decreases,. Incorporation of merosin (laminin-211) or the short laminin globular (LG4-5) modules of the laminin α2 chain C-terminus (called 2E3) that binds α-dystroglycan diminishes both apoptosis and necrosis and increases viability while bovine serum albumin had a much lesser effect, showing the specificity of this effect for these matrix proteins. One sarcolemma receptor for laminin-binding is α-dystroglycan. An antibody which binds α-dystroglycan but which does not block laminin-binding (VIA4) had little effect on apoptosis or viability on merosin or 2E3 embedded plates while another antibody (IIH6) which specifically blocks binding dramatically decreased viability and increased apoptosis. When merosin or 2E3 are added to culture media rather than embedded on plates these can also increase viability and decrease apoptosis even though the cells remain in suspension, though the effect is not as great as found for the embedded proteins where the cells attach. Thus, we conclude that the binding of a small LG4-5 modules of laminin-211 to α-dystroglycan is important in preventing anoikis and that attachment plus binding is necessary for maximal cell survival. PMID:19739104

  11. Mechanical Properties of Surface-Charged Poly(Methyl Methacrylate) as Denture Resins

    PubMed Central

    Park, Sang E.; Chao, Maggie; Raj, P. A.

    2009-01-01

    The aim of this study was to examine the mechanical properties of a new surface-modified denture resin for its suitability as denture base material. This experimental resin is made by copolymerization of methacrylic acid (MA) to poly(methyl methacrylate) (PMMA) to produce a negative charge. Four experimental groups consisted of Orthodontic Dental Resin (DENTSPLY Caulk) as a control and three groups of modified PMMA (mPMMA) produced at differing ratios of methacrylic acid (5 : 95, 10 : 90, and 20 : 80 MA : MMA). A 3-point flexural test using the Instron Universal Testing Machine (Instron Corp.) measured force-deflection curves and a complete stress versus strain history to calculate the transverse strength, transverse deflection, flexural strength, and modulus of elasticity. Analysis of Variance and Scheffe Post-test were performed on the data. Resins with increased methacrylic acid content exhibited lower strength values for the measured physical properties. The most significant decrease occurred as the methacrylic acid content was increased to 20% mPMMA. No significant differences at P < .05 were found in all parameters tested between the Control and 5% mPMMA. PMID:20339462

  12. Conversion of (Meth)acrylic acids to methane granular sludge: Initiation by specific anerobic microflora

    SciTech Connect

    Shtarkman, N.B.; Obraztova, A.Y.; Laurinavichyus, K.S.; Galushko, A.S.; Akimenko, V.K.

    1995-03-01

    The role of a specific anaerobic microflora in the initiation of degradation of (meth)acrylic acids to methane by granular sludge from a UASB reactor was investigated. Associations of anaerobic bacteria isolated from the anaerobic sludge, which was used for a long time for treatment of wastewater from (meth)acrylate production, were able to realize the initial stage of (meth)acrylic acid decomposition, i.e., a conversion of acrylic and methacrylic acids to propionic and isobutyric acids, respectively. When added to granules, these association played a role of an {open_quotes}initiator{close_quotes} of the degradation process, which was then continued by the granular sludge microflora utilizing propionate and isobutyrate. Some characteristics of the granules adapted to propionate or isobutyrate are presented. The rates of propionate and isobutyrate consumption by adapted granules is, respectively, 21 and 53 times higher than the values obtained for nonadapted granules. A combined use of {open_quotes}initiating{close_quotes} bacteria and adapted granules provided degradation of (meth)acrylic acids with a maximum methane yield. The possibility is discussed of employing the granules, which are adapted to short-chain fatty acids, and the {open_quotes}initiating{close_quotes} bacteria, which accomplish the initial steps of the organic material decomposition to lower fatty acids, for the conversion of various chemical compounds to methane. 10 refs., 3 figs., 2 tabs.

  13. Flexural properties of ethyl or methyl methacrylate-UDMA blend polymers.

    PubMed

    Kanie, Takahito; Kadokawa, Akihiko; Arikawa, Hiroyuki; Fujii, Koichi; Ban, Seiji

    2010-10-01

    Light-curing polyethyl methacrylate (PEMA)-urethane dimethacrylate (UDMA) resins and polymethyl methacrylate (PMMA)-UDMA resins were prepared by two processes. For first step, PEMA or PMMA powders were fully dissolved in ethyl methacrylate (EMA) or methyl methacrylate (MMA) and then the PEMA-EMA/PMMA-MMA mixtures were mixed with UDMA. The flexural properties of cured PEMA-UDMA and PMMA-UDMA polymers were measured using two PEMA (Mw: 300,000-400,000 and 650,000-1,000,000) and three PMMA (Mw: 30,000-60,000, 350,000 and 650,000-1,000,000) powders with different molecular weight, four mixing ratios of PMMA-MMA, and three mixing ratios of PMMA-MMA mixture and UDMA oligomer. Polymers with PMMA(Mw: 350,000) MMA=25/50, and with PMMA(Mw: 350,000)-MMA/UDMA=1/2 and =1/1, showed no-fracture in a flexural test at 1 mm/min and flexural strength and flexural modulus showed no significant difference compared with those of commercially available heat- and self-curing acrylic resins (p>0.01). Within limitation of this investigation, methyl methacrylate-UDMA blend polymer of this composition is available for denture base resin. PMID:20733259

  14. Synthesis and properties of a novel UV-cured fluorinated siloxane graft copolymer for improved surface, dielectric and tribological properties of epoxy acrylate coating

    NASA Astrophysics Data System (ADS)

    Yan, Zhenlong; Liu, Weiqu; Gao, Nan; Wang, Honglei; Su, Kui

    2013-11-01

    A novel functional fluorinated siloxane graft copolymer bearing with vinyl end-groups was synthesized from dihydroxypropyl-terminated poly(dimethylsiloxane) (PDMS), dicarboxyl terminated poly(2,2,3,4,4,4-hexafluorobutyl acrylate) oligomer (CTHFA), 2,4-toluene diissocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA). The chemical structure was characterized by FT-IR and GPC. The effect of concentration of the vinyl-capped fluorosilicone graft copolymer (Vi-PFSi) on the surface, thermal properties, dielectric and tribological properties of UV-cured films was investigated. Contact angles and surface energies showed that the high hydrophobic and oleophobic surfaces were obtained by incorporation of Vi-PFSi at very low amount (0.5 wt%). X-ray photoelectron spectroscopy (XPS) evidenced that the fluorinated and siloxane moiety selectively migrated to the outermost surface of UV-cured film, thus reduced its surface energy from 45.42 to 15.40 mN/m2 without affecting its bulk properties. The morphology of fracture surface of modified film exhibited rough fracture surface only at the outermost surface, revealing fluorinated and siloxane groups migrated toward air-side surface. The dielectric constants decreased from 5.32 (1 MHz) for bisphenol-A epoxy methacrylate (EMA) to 2.82 (1 MHz) for modified film when the Vi-PFSi copolymer concentration increased from 0 to 0.8 wt%. Tribological results from abrasion tester suggested that the Vi-PFSi could obviously reduce the abrasion weight loss of modified films.

  15. Novel silicone hydrogel based on PDMS and PEGMA for contact lens application.

    PubMed

    Lin, Chien-Hong; Yeh, Yi-Hsing; Lin, Wen-Ching; Yang, Ming-Chien

    2014-11-01

    A silicone-based hydrogel was synthesized from poly(dimethylsiloxane) dialkanol (PDMS), isophorone diisocyanate (IPDI), 2-hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methacrylate (PEGMA). The hydrophilicity of the resulting block copolymer was adjustable by manipulating the ratio of PDMS and PEGMA. The results showed that higher PEGMA content led to a lower water contact angle, higher water content, lower elastic modulus and higher glucose permeability. At a PEGMA content of 20%, the protein adsorption decreased to 23% and 18% for lysozyme and human serum albumin (HSA), respectively, of those of the control (PDMS-PU). This indicated that the PDMS-PU-PEGMA hydrogels exhibited an ability to resist protein adsorption. The oxygen permeability (Dk) was 92 barrers for the hydrogel with 20% PEGMA. Furthermore, these hydrogels were non-cytotoxic according to an in vitro L929 fibroblast assay. Overall, the results demonstrated that the PDMS-PU-PEGMA hydrogels exhibited not only relatively high oxygen permeability and relative optical transparency, but also hydrophilicity and anti-protein adsorption; therefore, they would be applicable as a contact lens material. Furthermore, this study demonstrated a new approach to controlling the performance of silicone hydrogels. PMID:25465755

  16. Polymerizable disulfide paclitaxel prodrug for controlled drug delivery.

    PubMed

    Ding, Yi; Chen, Wulian; Hu, Jianhua; Du, Ming; Yang, Dong

    2014-11-01

    A polymerizable disulfide paclitaxel (PTX) prodrug was synthesized by the consequential esterification reactions of 3,3'-dithiodipropionic acid (DTPA), a disulfide compound containing two active carboxyl groups, with 2-hydroxyethyl methacrylate (HEMA) and PTX. The structure of the prodrug was confirmed by (1)H NMR characterization. Then, the polymerizable prodrug was copolymerized with poly(ethylene glycol) methyl ether methacrylate (PEGMEA) to obtain a copolymer with hydrophilic PEG side chains and PTX covalently linked onto the backbone via disulfide bonds. The loading content of PTX was 23%. In aqueous solution, this copolymer prodrug could self-assemble into micelles, with hydrophobic PTX as the cores and hydrophilic PEG-segment as the shells. In vitro cell assay demonstrated that this copolymer prodrug showed more apparent cytotoxicity to cancer cells than to human normal cells. After incubation for 48 h, the cell viability of HEK-293 cells (human embryo kidney cells) at 0.1 μg/mL PTX still remained more than 90%, however, that of HeLa cells (human cervical cancer cells) decreased to 52%. PMID:25280719

  17. Micro-patterning and characterization of PHEMA-co-PAM-based optical chemical sensors for lab-on-a-chip applications

    PubMed Central

    Zhu, Haixin; Zhou, Xianfeng; Su, Fengyu; Tian, Yanqing; Ashili, Shashanka; Holl, Mark R.; Meldrum, Deirdre R.

    2012-01-01

    We report a novel method for wafer level, high throughput optical chemical sensor patterning, with precise control of the sensor volume and capability of producing arbitrary microscale patterns. Monomeric oxygen (O2) and pH optical probes were polymerized with 2-hydroxyethyl methacrylate (HEMA) and acrylamide (AM) to form spin-coatable and further crosslinkable polymers. A micro-patterning method based on micro-fabrication techniques (photolithography, wet chemical process and reactive ion etch) was developed to miniaturize the sensor film onto glass substrates in arbitrary sizes and shapes. The sensitivity of fabricated micro-patterns was characterized under various oxygen concentrations and pH values. The process for spatially integration of two sensors (Oxygen and pH) on the same substrate surface was also developed, and preliminary fabrication and characterization results were presented. To the best of our knowledge, it is the first time that poly (2-hydroxylethyl methacrylate)-co-poly (acrylamide) (PHEMA-co-PAM)-based sensors had been patterned and integrated at the wafer level with micron scale precision control using microfabrication techniques. The developed methods can provide a feasible way to miniaturize and integrate the optical chemical sensor system and can be applied to any lab-on-a-chip system, especially the biological micro-systems requiring optical sensing of single or multiple analytes. PMID:23175599

  18. Surface plasmon resonance sensor for femtomolar detection of testosterone with water-compatible macroporous molecularly imprinted film.

    PubMed

    Zhang, Qingwen; Jing, Lijing; Zhang, Jinling; Ren, Yamin; Wang, Yang; Wang, Yi; Wei, Tianxin; Liedberg, Bo

    2014-10-15

    A novel water-compatible macroporous molecularly imprinted film (MIF) has been developed for rapid, sensitive, and label-free detection of small molecule testosterone in urine. The MIF was synthesized by photo copolymerization of monomers (methacrylic acid [MAA] and 2-hydroxyethyl methacrylate [HEMA]), cross-linker (ethylene glycol dimethacrylate, EGDMA), and polystyrene nanoparticles (PS NPs) in combination with template testosterone molecules. The PS NPs and template molecules were subsequently removed to form an MIF with macroporous structures and the specific recognition sites of testosterone. Incubation of artificial urine and human urine on the MIF and the non-imprinted film (NIF), respectively, indicated undetectable nonspecific adsorption. Accordingly, the MIF was applied on a surface plasmon resonance (SPR) sensor for the detection of testosterone in phosphate-buffered saline (PBS) and artificial urine with a limit of detection (LOD) down to 10(-15)g/ml. To the best of our knowledge, the LOD is considered as one of the lowest among the SPR sensors for the detection of small molecules. The control experiments performed with analogue molecules such as progesterone and estradiol demonstrated the good selectivity of this MIF for sensing testosterone. Furthermore, this MIF-based SPR sensor shows high stability and reproducibility over 8months of storage at room temperature, which is more robust than protein-based biosensors. PMID:24991687

  19. Toughening epoxy resin with poly(methyl methacrylate)-grafted natural rubber

    SciTech Connect

    Rezaifard, A.H.; Hodd, K.A.; Barton, J.M.

    1993-12-31

    A novel rubber, poly(methyl methacrylate)-g-natural rubber (Hevea-plus MG), has been studied as a toughening agent for bisphenol A diglycidyl ether (Shell 828 epoxy resin) cured with piperidine. Effective dispersions of the rubber, in concentrations of 2-10 parts per hundred parts resin, were achieved by adjusting the solubility parameter of the epoxy to approximate that of poly(methyl methacrylate) by adding bisphenol A. The fracture energy of the rubber-modified resin was determined by compact tension tests (in the temperature range -60 to +40{degrees}C) and by Charpy impact tests. The poly(methyl methacrylate)-g-natural rubber was found to be an effective toughening agent for the epoxy resin at both low and high rates of strain. Possible fracture mechanisms are discussed. 22 refs., 16 figs., 5 tabs.

  20. Effects of Surfactants on the Properties of Mortar Containing Styrene/Methacrylate Superplasticizer

    PubMed Central

    Negim, El-Sayed; Kozhamzharova, Latipa; Khatib, Jamal; Bekbayeva, Lyazzat; Williams, Craig

    2014-01-01

    The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA. PMID:24955426

  1. Chondrocyte Generation of Cartilage-Like Tissue Following Photoencapsulation in Methacrylated Polysaccharide Solution Blends.

    PubMed

    Hayami, James W S; Waldman, Stephen D; Amsden, Brian G

    2016-07-01

    Chondrocyte-seeded, photo-cross-linked hydrogels prepared from solutions containing 50% mass fractions of methacrylated glycol chitosan or methacrylated hyaluronic acid (MHA) with methacrylated chondroitin sulfate (MCS) are cultured in vitro under static conditions over 35 d to assess their suitability for load-bearing soft tissue repair. The photo-cross-linked hydrogels have initial equilibrium moduli between 100 and 300 kPa, but only the MHAMCS hydrogels retain an approximately constant modulus (264 ± 5 kPa) throughout the culture period. Visually, the seeded chondrocytes in the MHAMCS hydrogels are well distributed with an apparent constant viability in culture. Multicellular aggregates are surrounded by cartilaginous matrix, which contain aggrecan and collagen II. Thus, co-cross-linked MCS and MHA hydrogels may be suited for use in an articular cartilage or nucleus pulposus repair applications. PMID:27061241

  2. Toward pH-responsive coating materials--high-throughput study of (meth)acrylic copolymers.

    PubMed

    Krieg, Andreas; Arici, Elif; Windhab, Norbert; Schattka, Jan Hendrik; Schubert, Stephanie; Schubert, Ulrich S

    2014-08-11

    The release behavior of a model compound (β-naphthol orange) encapsulated in (meth)acrylate-based statistical copolymers under different environmental conditions was investigated. From monomers of varying polarity (methyl acrylate, ethyl acrylate, tert-butyl acrylate, 2-ethylhexyl methacrylate, and benzyl methacrylate) in combination with methacrylic acid, five polymer series were synthesized by free radical polymerization. The pH-dependent release kinetics were investigated via UV-vis spectroscopy at pH 1.2 and 6.8, simulating physiological conditions in the stomach and intestines. Furthermore, the influence of different ethanol contents (0 and 40 vol %) in the acidic medium was investigated. The whole approach was designed to meet the requirements of a high-throughput experimentation workflow. PMID:24964068

  3. Designing ultraviolet curing of multifunctional (meth)acrylate hard coats

    NASA Astrophysics Data System (ADS)

    Wen, Mei

    Ultraviolet (UV) curing rapidly converts multifunctional (meth)acrylate liquid monomers into highly cross-linked, impervious, hard polymeric coatings at ambient temperature. This solidification process occurs by free-radical cross-linking polymerization. To achieve a better design of this process, it is desirable to have high conversion of functional groups, low stress, adequate mechanical properties, and low costs. To approach this design goal, the following modeling and experimental work was carried out. Firstly, a kinetic model was developed to simulate radical trapping. This model predicts a peak in the concentration of active radicals and a monotonic rise of the concentration of trapped radicals during polymerization. It also predicts a decrease in the fraction of trapped radicals at a given conversion as the UV light intensity is raised. Secondly, a kinetic gelation model, in which reaction occurs locally on a lattice, was developed. Unlike previous such models, this model accounts for free radical reaction time more accurately. It was found that a more uniform distribution of reacted sites leads to a favored propagation at a given conversion. Moreover, radical trapping and termination were found to shorten the kinetic chain length and to lower the asymptotic conversion reached when initiators are exhausted. Thirdly, elastic modulus evolution was simulated with a rigidity percolation model, in which bonds created by free-radical polymerization are represented as rigidly jointed beams. Simulations show that modulus of a network depends on the connectivity between monomer units as well as bonding structure. Finally, experimental determination of volume shrinkage of a sandwiched film was measured with a dynamic mechanical analyzer probe. A faster reaction causes more severely delayed volume shrinkage from the thermodynamic equilibrium volume required by the reaction. Nevertheless, volume shrinks more when the shrinkage of the thermodynamic volume rises. In

  4. Mutagenicity assessment of acrylate and methacrylate compounds and implications for regulatory toxicology requirements.

    PubMed

    Johannsen, F R; Vogt, Barbara; Waite, Maureen; Deskin, Randy

    2008-04-01

    Esters of acrylic acid and methacrylic acid, more commonly known as acrylates and methacrylates, respectively, are key raw materials in the coatings and printing industry, with several of its chemical class used in food packaging. The results of over 200 short-term in vitro and in vivo mutagenicity studies available in the open literature have been evaluated. Despite differences in acrylate or methacrylate functionality or in the number of functional groups, a consistent pattern of test response was seen in a typical regulatory battery of mutagenicity tests. No evidence of point mutations was observed when acrylic acid or over 60 acrylates and methacrylates were investigated in Salmonella bacterial tests or in hprt mutation tests mammalian cells, and no evidence of a mutagenic effect was seen when tested in whole animal clastogenicity and/or aneuploidy (chromosomal aberration/micronucleus) studies. Consistent with the in vivo testing results, acrylic acid exhibited no evidence of carcinogenicity in chronic rodent cancer bioassays. In contrast, acrylic acid and the entire acrylate and methacrylate chemical class produced a consistently positive response when tested in the mouse lymphoma assay and/or other in vitro mammalian cell assays designed to detect clastogenicity. The biological relevance of this in vitro response is questioned based on the non-concordance of in vitro results with those of in vivo studies addressing the same mutagenic endpoint (clastogenicity). Thus, in short-term mutagenicity tests, the acrylates and methacrylates behave as a single chemical category, and genotoxicity behavior of a similar chemical can be predicted with confidence by inclusion within this chemical class, thus avoiding unnecessary testing. PMID:18346829

  5. Effect of bifunctional comonomers on mechanical strength and water sorption of amorphous calcium phosphate- and silanized glass-filled Bis-GMA-based composites.

    PubMed

    Skrtic, Drago; Antonucci, Joseph M

    2003-08-01

    This study seeks to elucidate structure-property relationships in a series of unfilled dental copolymers and their composites. The copolymers/composites were derived from photo-activated binary monomer systems based on 2,2-bis[p-2'-hydroxy-3'-methacryloxypropoxy)phenyl] propane (Bis-GMA) and equimolar amounts of a bifunctional, surface-active comonomer, i.e., 2-hydroxyethyl methacrylate (HEMA), glycerol dimethacrylate (GDMA) or ethylene glycol methacrylate phosphate (PHEMA). Triethyleneglycol dimethacrylate, a widely used comonomer for Bis-GMA, was used as a control. Two types of fillers were investigated: (1) a hydrophilic, silica-modified amorphous calcium phosphate (Si-ACP) and (2) a more hydrophobic, silanized nanosized silica (n-SiO(2)). Both the unfilled copolymers and their composites were evaluated for biaxial flexure strength (BFS), both dry and wet after 30 days immersion in buffered saline, and for water sorption (WS) and their WS kinetic profiles. The Bis-GMA copolymers and composites derived from HEMA and GDMA had BFS and WS values, as well as WS kinetic profiles, similar to the controls. Copolymers and composites based on Bis-GMA/PHEMA had lower BFS and higher WS values. Si-ACP composites had significantly lower BFS values (that were further diminished on soaking) than their copolymers. WS increased as the level of this filler was increased except for Bis-GMA/PHEMA composites. With n-SiO(2) as the filler, a more moderate reduction in BFS occurred compared to the unfilled copolymers. By contrast to Si-ACP composites, the WS of all the n-SiO(2) composites decreased with increasing filler level. From this study it is evident that both the chemical structure of the polymer matrix and the type of filler system can have significant effects on the strength and water-related properties of dental composites. PMID:12742726

  6. Synthesis and characterization of carbon fibers functionalized with poly (glycidyl methacrylate) via atom transfer radical polymerization

    NASA Astrophysics Data System (ADS)

    Wu, Yongwei; Xiong, Lei; Qin, Xiaokang; Wang, Zhengyue; Ding, Bei; Ren, Huan; Pi, Xiaolong

    2015-07-01

    In this work, polyacrylonitrile (PAN)-based carbon fibers (CF) were chemically modified with poly (glycidyl methacrylate) (PGMA) via atom transfer radical polymerization (ATRP) to improve the interaction between the CF and polymer matrix. The FT-IR, TGA, and XPS were used to determine the chemical structure of the resulting products and the quantities of PGMA chains grafted from the CF surface. The experimental results confirm that the CF surface was functionalized and glycidyl methacrylate was graft-polymerized onto the CF, and the grafting content of polymer could reach 10.2%.

  7. pH-sensitive methacrylic copolymer gels and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-05-15

    The present invention provides novel gel forming methacrylic blocking copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility. 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. The polymers may be used for drug and gene delivery, protein separation, as structural supplements, and more.

  8. Synthesis and physicochemical properties of organofluorine esters of acrylic, methacrylic, and maleic acids

    SciTech Connect

    Gol'din, G.S.; Averbakh, K.O.; Lavygin, I.A.; Nekrasova, L.A.

    1985-12-01

    The authors synthesize and study the physicochemical properties of organofluorine acrylates, methacrylates, and maleates. The organofluorine esters are colorless liquids; their composition and structure were confirmed by elemental analysis and IR spectra. The results of studies of the dependence of the density, surface tension, and viscosity of these compounds on temperature are presented. The results revealed the influence of the length of the fluorocarbon chain on the combination of the physicochemical properties of organofluorine acrylates, methacrylates, and maleates, and also provided a method for estimating certain thermophysical characteristics of such compounds without recourse to experimental measurements.

  9. Balancing Size Exclusion and Adsorption of Methacrylate Polymers in Nanoporous Silica

    NASA Astrophysics Data System (ADS)

    Abdulahad, Asem; Lee, Sekyung; Chang, Taihyun; Ryu, Chang

    2010-03-01

    Liquid chromatography at the critical condition (LCCC) is a high performance liquid chromatography (HPLC) technique that lies between size exclusion chromatography (SEC) and adsorption-based interaction chromatography (IC) where the elution of polymers becomes independent of polymer molecular weight. At LCCC, the balance between the entropic exclusion and the enthalpic adsorption interactions between polymers and stationary phases results in the simultaneous elution of polymers regardless of molecular weight. Using C18-bonded silica chromatographic columns we demonstrate the LCCC elution of a series of methacrylate polymers and discuss how the alkyl side groups in methacrylate polymers affects the adsorption of polymer chains against the size exclusion in nanopores.

  10. Effect of filling technique on the bond strength of methacrylate and silorane-based composite restorations.

    PubMed

    Machado, Fernanda Weingartner; Borges, Fernanda Blos; Cenci, Maximiliano Sérgio; Moraes, Rafael Ratto de; Boscato, Noéli

    2016-01-01

    The bond strength of methacrylate (Z350, 3M ESPE) and silorane (P90, 3M ESPE) restorations, using different cavity filling techniques, was investigated. Cavities (6 × 3 × 3) in bovine teeth were filled using bulk, oblique, or horizontal increments. A push-out test was carried out after 24 h. Data were statistically analyzed (α = 5%). Methacrylate-based composites and the horizontal filling technique showed the highest bond strength values (10.2 ± 3.9, p < 0.05). Silorane-based composites showed no statistically significant differences regarding the filling techniques (p > 0.05). PMID:27050940

  11. Terminal-Selective Transesterification of Chlorine-Capped Poly(Methyl Methacrylate)s: A Modular Approach to Telechelic and Pinpoint-Functionalized Polymers.

    PubMed

    Ogura, Yusuke; Terashima, Takaya; Sawamoto, Mitsuo

    2016-04-20

    Terminal-selective transesterification of chlorine-capped poly(methyl methacrylate)s (PMMA-Cl) with alcohols was developed as a modular approach to create telechelic and pinpoint-functionalized polymers. Being sterically less hindered and electronically activated, both the α-end ethyl ester and ω-end methyl ester of PMMA-Cl were efficiently and selectively transesterified with diverse alcohols in the presence of a titanium alkoxide catalyst, while retaining the pendent esters intact, to almost quantitatively give various chlorine-capped telechelic PMMAs. In sharp contrast to conventional telechelic counterparts, the telechelic polymers obtained herein yet carry a chlorine atom at the ω-terminal to further work as a macroinitiator in living radical polymerization. The iterative process of living radical polymerization and terminal-selective transesterification successfully afforded unique pinpoint-functionalized polymers where a single functional monomer unit was introduced into the desired site of the polymer chains. PMID:27040865

  12. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer. 177.1030 Section 177.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components...

  13. Recent Origin of the Methacrylate Redox System in Geobacter sulfurreducens AM-1 through Horizontal Gene Transfer

    PubMed Central

    Arkhipova, Oksana V.; Meer, Margarita V.; Mikoulinskaia, Galina V.; Zakharova, Marina V.; Galushko, Alexander S.; Kondrashov, Fyodor A.

    2015-01-01

    The origin and evolution of novel biochemical functions remains one of the key questions in molecular evolution. We study recently emerged methacrylate reductase function that is thought to have emerged in the last century and reported in Geobacter sulfurreducens strain AM-1. We report the sequence and study the evolution of the operon coding for the flavin-containing methacrylate reductase (Mrd) and tetraheme cytochrome с (Mcc) in the genome of G. sulfurreducens AM-1. Different types of signal peptides in functionally interlinked proteins Mrd and Mcc suggest a possible complex mechanism of biogenesis for chromoproteids of the methacrylate redox system. The homologs of the Mrd and Mcc sequence found in δ-Proteobacteria and Deferribacteres are also organized into an operon and their phylogenetic distribution suggested that these two genes tend to be horizontally transferred together. Specifically, the mrd and mcc genes from G. sulfurreducens AM-1 are not monophyletic with any of the homologs found in other Geobacter genomes. The acquisition of methacrylate reductase function by G. sulfurreducens AM-1 appears linked to a horizontal gene transfer event. However, the new function of the products of mrd and mcc may have evolved either prior or subsequent to their acquisition by G. sulfurreducens AM-1. PMID:25962149

  14. 21 CFR 177.2465 - Polymethylmethacrylate/poly(trimethoxysilylpropyl)methacrylate copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polymethylmethacrylate/poly(trimethoxysilylpropyl)methacrylate copolymers. 177.2465 Section 177.2465 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use Only...

  15. 21 CFR 177.2465 - Polymethylmethacrylate/poly(trimethoxysilylpropyl)methacrylate copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polymethylmethacrylate/poly(trimethoxysilylpropyl)methacrylate copolymers. 177.2465 Section 177.2465 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use Only...

  16. 21 CFR 177.2465 - Polymethylmethacrylate/poly(trimethoxysilylpropyl)methacrylate copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polymethylmethacrylate/poly(trimethoxysilylpropyl)methacrylate copolymers. 177.2465 Section 177.2465 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use Only as Components of Articles Intended...

  17. 21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...(hydroxyethyl methacrylate). The dyes that may be used alone or in combination are (1) Reactive Black 5 (CAS Reg...)-, sulfo((4-((2-sulfooxy)ethyl)sulfonyl)phenyl)amino) sulfonyl derivs] (CAS Reg. No. 73049-92-0); (3) Reactive Orange 78 CAS Reg. No. 68189-39-9); (4) Reactive Yellow 15 (CAS Reg. No. 60958-41-0); (5)...

  18. 21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...(hydroxyethyl methacrylate). The dyes that may be used alone or in combination are (1) Reactive Black 5 (CAS Reg...)-, sulfo((4-((2-sulfooxy)ethyl)sulfonyl)phenyl)amino) sulfonyl derivs] (CAS Reg. No. 73049-92-0); (3) Reactive Orange 78 CAS Reg. No. 68189-39-9); (4) Reactive Yellow 15 (CAS Reg. No. 60958-41-0); (5)...

  19. Controlled Degradation of Poly(Ethyl Cyanoacrylate-Co-Methyl Methacrylate)(PECA-Co-PMMA) Copolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper describes a method for modifying poly(ethyl cyanoacrylate) in order to control the degradation and the stability as well as the glass transition temperatures. Copolymers of poly(ethyl cyanoacrylate-co-methyl methacrylate) (PECA-co-PMMA) with various compositions were synthesized by free ...

  20. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer. 721.7200 Section 721.7200 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...