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In this study, the development of a novel cell support material was purposed as due to the serum-free cultivation of tissue cells. This material was prepared by immobilizing RGD (Arg-Gly-Asp) sequence of cell-adhesion factor, fibronectin, and cell-growth factor, insulin, to the three-dimensional non-woven polyester fabric (briefly NWPF) discs that have been used successfully in our previous cell culture studies. At first these matrices were partially hydrolyzed and then the carboxyl groups were coupled with RGD or insulin in the presence of water-soluble carbodiimide. The effectiveness of immobilization process was checked with SEM, ATR-FTIR spectroscopy and swelling studies. The maximum amount of immobilized insulin was 6.96 micorgcm(-2) and it was obtained at 200 micorgml(-1) initial insulin concentration for 60 min immobilization period. The cell culture studies which were carried out with human skin fibroblasts (HS An1) showed that, percentage of adhesion on RGD modified NWPF discs is higher than that of other surfaces. i.e., unmodified discs, polystyrene Petri dishes and insulin-immobilized discs, in serum-free culture. According to the results of growth studies, highest cell yield was obtained in the case of insulin-modified discs.
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PMID:Biomodification of non-woven polyester fabrics by insulin and RGD for use in serum-free cultivation of tissue cells. 1216 25

We report the development of new biomacromolecule coatings on biodegradable biomaterials based on electrostatic assembly of extracellular matrix-like molecules. Poly(ethylene imine) (PEI) was employed to engineer poly(dl-lactide) (PDL-LA) substrate to obtain a stable positively charged surface. An extracellular matrix- (ECM-) like biomacromolecule, gelatin, was selected as the polyelectrolyte to deposit on the activated PDL-LA substrate via the electrostatic assemble technique. The extracellular matrix-like multilayer on the PDL-LA substrate was investigated by attenuated total reflection (ATR-FTIR), X-ray photoelectron spectrscopy (XPS), contact angle, and atomic force microscopy (AFM). The gradual buildup of the protein layer was investigated by UV-vis spectra, and it was further given a quantitative analysis of the protein layer on the PDL-LA substrate via the radioiodination technique. The stability of the protein layer under aqueous condition was also tested by the radiolabeling method. Chondrocyte was selected as the model system for testing the cell behavior and morphology on modified PDL-LA substrates. The chondrocyte test about cell attachment, proliferation, cell activity and cell morphology by SEM, and confocal laser scanning microscopy (CLSM) investigation on extracellular matrix-like multilayer modified PDL-LA substrate was shown to promote chondrocyte attachment and growth. Comparing conventional coating methods, polyelectrolyte multiplayers are easy and stable to prepare. It may be a good choice for the modification of 3-D scaffolds used in tissue engineering. These very flexible systems allow broad medical applications for drug delivery and tissue engineering.
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PMID:Surface engineering of poly(DL-lactide) via electrostatic self-assembly of extracellular matrix-like molecules. 1262 35

To obtain insights into a correlation relationship between the structure and the aggregation mode in an organogel system, we synthesized gelators 2a-4a bearing a porphyrin moiety as a one-dimensional aggregation unit and amide groups as peripheral hydrogen-bonding sites. Gelators 3a and 3b bearing the amide groups at the 4-position of the meso-phenyl groups are classified as versatile gelators, gelating 10 and 14 solvents, respectively, among 23 solvents tested herein. In contrast, gelators 2a and 4a bearing the amide groups at the 3,5-positions and 3-position, respectively, are classified as poor gelators. Examination by spectroscopic methods (UV-vis, ATR-FTIR, XRD, etc.) revealed that in the organogel phase porphyrins in 3a adopt the H aggregation mode whereas those in 2a and 4a adopt the J aggregation mode. X-ray analysis of the single crystals established that in fact 3b features a columnar stack of porphyrin moieties that can be classified as the H-aggregate, whereas 2a results in a two-dimensional a-b plane, in which porphyrin moieties are arranged in the J-aggregate. Very interestingly, the difference in the H versus J aggregation mode is well-reflected by the difference in the macroscopic aggregate morphology observed by SEM: 3a + cyclohexane gel results in a one-dimensionally aggregated fibrillar structure, whereas 2a + cyclohexane gel results in a two-dimensional sheetlike structure. These findings indicate that the H versus J aggregation mode of porphyrin stacks can be controlled by the peripheral hydrogen-bonding interactions and the microscopic hydrogen-bonding network structure is well-reflected by the macroscopic SEM-observed structure.
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PMID:Hydrogen-bond-assisted control of H versus J aggregation mode of porphyrins stacks in an organogel system. 1281 56

A tetraphenylporphyrin (1b) bearing amide groups at the 3,5-positions of the meso-phenyl groups is assembled into a two-dimensional sheetlike structure and acts as an organogelator. When [60]fullerene was added, the sheetlike structure was dramatically changed into a one-dimensional fibrous structure, and both the gelation ability and the gel stability were improved. The stoichiometry between [60]fullerene and 1b was determined to be 1:2. Examination utilizing SEM and TEM observations, UV-vis and ATR IR spectral analyses, and XRD analysis revealed that an amide-amide hydrogen-bonding interaction creates a cavity, the size of which is complementary to that of [60]fullerene, and these cavities are connected by another amide-amide hydrogen-bonding interaction to provide a one-dimensional multicapsular structure. This is a novel example that the superstructure constructed in an organogel system is drastically changed by added [60]fullerene.
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PMID:[60]fullerene-motivated organogel formation in a porphyrin derivative bearing programmed hydrogen-bonding sites. 1291 35

A series of SO2 sorbents 5%-90% (mass percent) Na2CO3/straw were prepared by conventional incipient wetness impregnation of straw with an aqueous solution of Na2CO3. It was showed that small particle size (< or = 0.28 mm) of the straw and low flow rate (40 mL/min) of the feed gas favor the removal of SO2, while temperature (70 degrees C-300 degrees C) has little effect on the desulfurization efficiency. Based on XRD, SEM and ATR-IR analysis it can be concluded that the Na2CO3 on the surface of the straw is mainly in an amorphous state. The unique structural features of the straw and its interaction with Na2CO3 lead to the amorphous structure having greater surface area (12.14 m2/g) and pore volume (0.093 cm3/g) with a high loading of Na2CO3.
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PMID:[Reparation and desulfurization of Na2CO3/straw sorbents for removing SO2 from flue gas]. 1476 68

This study used an in vitro environment that simulated the microenvironment at the adherent cell-material interface to reproduce and accelerate the biodegradation of poly(ether urethane) (PEU) and poly(carbonate urethane) (PCU). Polyurethane films were treated in vitro for 24 days in 20% hydrogen peroxide/0.1 M cobalt chloride solution at 37 degrees C. Characterization with ATR-FTIR and SEM showed soft segment and hard segment degradation consistent with the chemical changes observed after long-term in vivo treatment. Overall, the PCU underwent less degradation and the degraded surface layer was much thinner than PEU. Nevertheless, the results supported a common oxidation mechanism for biodegradation of these polymers. The observed in vitro degradation was inhibited by adding an antioxidant to the polyurethane film. Our findings further support the use of the in vitro H(2)O(2)/CoCl(2) system in evaluating the biostability of polyurethanes under accelerated conditions.
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PMID:Oxidative mechanisms of poly(carbonate urethane) and poly(ether urethane) biodegradation: in vivo and in vitro correlations. 1522 69

The ability of micropatterned surfaces to modulate cell behavior is combined with the well-known angiogenic property of the hyaluronan-Cu (II) complex. Hyaluronan-Cu (II) microstripes 100 and 25 mum wide on aminosilanised glass substrates were fabricated by photoimmobilization following two different methods: i.e., method I consisting in the photoimmobilization of the Hyal-Cu (II) complex; and method II based on the photoimmobilization of Hyal followed by the coordination with Cu (II). The chemistry and topography of the fabricated micropatterned samples were investigated by ATR FT-IR, atomic absorption, AFM, SEM, and ToF-SIMS. ATR FT-IR analysis demonstrated that hyaluronan conjugated with a photoreactive moiety was able to coordinate Cu (II) ions and that the photoimmobilization process was successful, as indicated by the intensity decrease of the IR band of the azidic group after the photoreaction. AFM and SEM images showed that reproducible Hyal-Cu (II) microstructures with both chemical and topographical heterogeneities have been obtained by the two preparation methods. The distribution of copper on the fabricated Hyal-Cu (II) microstructures has been investigated by ToF-SIMS. In both ToF-SIMS images and spectra, on Hyal-Cu (II) microstructures prepared by method I, the Cu peak (63 m/z) was detected only on the Hyal-Cu (II) microstripes, while on Hyal-Cu (II) microstructures prepared by method II, the Cu peak showed the same intensity both on the Hyal-Cu (II) microstripes and on the aminosilanised glass substrate, in agreement with the higher amount of Cu revealed by atomic absorption. The influence of Hyal-Cu (II) micropatterned surfaces on BAEC and LEC, in terms of migration and adhesion, has been analyzed. The results obtained indicate that Hyal-Cu (II) influences BAEC behavior inducing cell migration, while it is devoid of any effect on LEC.
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PMID:Role of the Hyal-Cu (II) complex on bovine aortic and lymphatic endothelial cells behavior on microstructured surfaces. 1563 23

The synthesis of four bis(trialkoxysilylated) organic molecules capable of self-assembly--(EtO)3Si(CH2)3NHCONH-(CH2)n-NHCONH(CH2)3Si(OEt)3 (n = 9-12)--associating urea functional groups and alkylidene chains of variable length is described. These compounds behave as organogelators, forming supramolecular assemblies thanks to the intermolecular hydrogen bonding of urea groups. Whereas fluoride ion-catalysed hydrolysis in ethanol in the presence of a stoichiometric amount of water produced amorphous hybrids, acid-catalysed hydrolysis in an excess of water gave rise to the formation of crystalline lamellar hybrid materials through a self-organisation process. The structural features of these nanostructured organic/inorganic hybrids were analysed by several techniques: attenuated Fourier transformed infrared (ATR-FTIR), solid-state NMR spectroscopy (13C and 29Si), scanning and transmission electron microscopy (SEM and TEM) and powder X-ray diffraction (PXRD). The reaction conditions, the hydrophobic properties of the long alkylidene chains and the hydrogen-bonding properties of the urea groups are determining factors in the formation of these self-assembled nanostructured hybrid silicas.
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PMID:Lamellar bridged silsesquioxanes: self-assembly through a combination of hydrogen bonding and hydrophobic interactions. 1566 78

The effect of fibronectin protein (Fn) coating onto polysaccharide layers of hyaluronic acid (Hyal) and its sulfated derivative (HyalS) on fibroblast cell adhesion was analyzed. The Hyal or HyalS were coated and grafted on the glass substrate by a photolithographic method. The Fn coating was achieved by two different routes: the immobilization of Fn by covalent bond to the polysaccharide layers and the simple adsorption of Fn onto Hyal and HyalS surfaces. AFM, SEM, and ATR-FTIR techniques were used for the chemical and topographical characterization of the surfaces. According to AFM and SEM data, the surface topography was dependent on the method used to cover the polysaccharide layers with the protein. ATR-FTIR analysis supplied information about the rearrangement of Fn after the interaction (adsorption or binding) with the Hyal and the HyalS. The conformational changes of the Fn were minimal when it was simply adsorbed on HyalS surfaces and larger once bound, whereas on the Hyal layer the protein underwent a bigger conformational change once adsorbed and covalently grafted. Then, the biological characterization was carried out by analyzing the human diploid skin fibroblasts adhesion on these surfaces. The morphology of fibroblasts was evaluated by SEM, whereas the dynamics of fibroblasts movement were recorded by a time-lapse system. Cell variations in area, perimeter, and length were analyzed at 2, 4, and 6 h. It was found that the addition of Fn (covalently bound or merely adsorbed) was fundamental in the promotion of fibroblasts adhesion and spreading. The greatest adhesion occurred onto HyalS layers covered by the adsorbed Fn.
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PMID:Fibroblast cell behavior on bound and adsorbed fibronectin onto hyaluronan and sulfated hyaluronan substrates. 1576 24

Plasma immersion ion implantation (PIII) was used to modify medical-grade PVC coated by triclosan and bronopol to enhance the antibacterial properties. The surface was first activated by O2 plasma to produce more hydrophilic groups so that triclosan and bronopol could be coated more effectively on the surface. Subsequently, an argon plasma treatment was conducted under optimal conditions to improve the antibacterial properties of the triclosan and bronopol-coated PVC samples. The modified surfaces were characterized by XPS, ATR-FTIR, SEM, and contact angle measurements. The antibacterial properties were evaluated utilizing the method of plate-counting of Staphylococcus aureus (gram positive) and Escherichia coli (gram negative). Our experimental results show that the plasma-modified PVC with bronopol exhibits good antibacterial properties while the favorable bulk properties of PVC are retained. The plasma-modified PVC with triclosan has better antibacterial performance against E. coli than bronopol. The change in the antibacterial effect on the modified PVC with time was also investigated and the antibacterial effect was observed to decrease with time.
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PMID:Plasma surface modification of poly vinyl chloride for improvement of antibacterial properties. 1600 57


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