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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A process was developed to coat complex medical devices with a thin, transparent, biocompatible film. The film is based on silicone rubber (SR) but has higher albumin affinity than SR. Two polymer forms have been developed: one substitutes hydroxyl groups (OH), the other, 16 carbon acyl groups (C16) in the siloxane side chains. Oxymercuration/demercuration or hydroboration reactions can be used. SEM reveals film surfaces are smooth, uniform, and featureless. ATR/FTIR spectra and advancing/receding water contact angle measurements confirm the presence of surface OH groups and suggest the presence of surface acyl groups. Albumin adsorption and retention are markedly enhanced for surface OH and C16 concentrations as low as 5% reaction yield. Kinetics, isotherm, and competitive albumin/fibrinogen adsorption studies suggest that surface hydroxylation, and perhaps C16 acylation as well, markedly improve the albumin affinity, but not the fibrinogen affinity, of this material. The SR film can be durably coated on several materials, making it possible to favorably treat many blood-contacting devices, using a simple immersion process.
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PMID:Biocompatible coatings with high albumin affinity. 225 85

The synthesis of new materials (PUPAs) based on a commercial polyurethane and a heparin-complexing polymer, poly(amido-amine), was studied. PUPAs are capable of adsorbing heparin because the basic nitrogens of poly(amido-amine), once protonated, interact with the negative charges carried by the heparin molecule. Six different samples of PUPA were synthesized having a varied ratio of the components. The quantity of basic nitrogen on the surface and the bound heparin for each sample was determined. Two different kinds of heparin are present on a PUPA surface: one is strongly bound but can be detached by 0.1 M NaOH solution, the other is physically adsorbed and is slowly released by a stream of saline solution. A relationship between the quantity of strongly bound heparin and basic nitrogen was found. SEM and FTIR-ATR analysis were performed on all the PUPA samples. The mechanical characteristics change according to chemical composition.
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PMID:Synthesis and physicochemical characterization of a new material (PUPA) based on polyurethane and poly(amido-amine) components capable of strongly adsorbing quantities of heparin. 276 25

Despite the use of polyurethanes in a number of blood-contacting applications, little is known about the contributing effects of the various polyurethane components in thrombogenesis. In order to investigate blood-polyurethane interactions, a number of different polyurethanes were examined in an acute canine ex vivo series shunt experiment. Multiprobe surface characterization techniques, including contact angle measurements, ESCA, ATR-IR, and SEM were used to obtain surface property information on the materials studied. The polyurethanes examined included several with different soft segment types, a series of materials with different hard segment diisocyanates and chain extenders, a series consisting of the same polymer cast from different solvents, a zwitterionomer, and a hard segment analog. Two commercial urethanes were also examined, and the effect of methanol extraction on these materials was studied. The blood-contact and surface characterization results indicated that both the surface concentration and type of hard segment were of importance in determining blood response. The relative concentration of hard segment on the polymer surface was found to affect the observed blood-material interaction, although the extent of this effect was found to depend on the hard and soft segment components of the copolymer system. Both the surface properties and thrombogenicity of a particular polyurethane were changed by casting from different solvents, indicating the need to optimize and control fabrication conditions. Methanol extraction was found to improve the thromboresistance of the commercial polyurethanes.
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PMID:Ex vivo interactions and surface property relationships of polyetherurethanes. 370 Apr 40

A PHEMA grafted polymer film was prepared by plasma induced graft copolymerization onto an elastic material, silicone rubber. The control, Ar plasma-treated, and PHEMA-grafted silicone rubber surfaces were characterized by ESCA, FTIR-ATR, and SEM techniques. ESCA verified the respective chemical shift of control and Ar plasma-treated films. The presence of the grafted PHEMA was also verified by ESCA. The amounts of grafted PHEMA did not monotonously increase with the plasma exposure conditions, but decreased after passing a maximum. The introduction of PHEMA onto a hydrophobic support provided an adequate surface for rabbit corneal epithelium cell attachment and growth. Cell attachment and growth onto these surfaces were examined by light microscopy. Cell attachment onto the control and Ar plasma-treated surface was negligible, while improved attachment and growth of rabbit corneal epithelium cells was demonstrated on the PHEMA-grafted polymer surface. The PHEMA-grafted silicone rubber surface demonstrated a confluent cell layer after 72 h.
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PMID:The effect of plasma-induced graft copolymerization of PHEMA on silicone rubber towards improving corneal epithelial cells growth. 815 9

A poly(2-hydroxyethyl methacrylate) (pHEMA)-grafted polymer film was prepared by plasma-induced graft copolymerization onto an elastic material, silicone rubber, and a plastic material, poly(4-methyl-1-pentene) (TPX). The control, Ar plasma-treated and pHEMA-grafted silicone rubber and TPX surfaces were characterized by ESCA, FTIR-ATR, SEM and contact angle techniques. ESCA verified the respective chemical shift of control and Ar plasma-treated films. The presence of the grafted pHEMA was also verified by ESCA. The introduction of pHEMA onto a hydrophobic support provided an adequate surface for rabbit corneal epithelium cell attachment and growth. Cell attachment and growth onto these surfaces were examined by light microscopy. Cell attachment onto the control and Ar plasma-treated surfaces was negligible, while improved attachment and growth of rabbit corneal epithelium cells was demonstrated on the pHEMA-grafted polymeric surface. At 72 h, the pHEMA-grafted silicone rubber surface attached and grew more cells as compared with those on a pHEMA-grafted TPX surface. The pHEMA-grafted silicone rubber surface demonstrated a confluent cell layer after 72 h.
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PMID:Plasma-induced graft copolymerization of HEMA onto silicone rubber and TPX film improving rabbit corneal epithelial cell attachment and growth. 819 88

In order to improve the thromboresistance of the commercial polyurethane(PU), its surface modification was accomplished by three new different methods and their surface characteristics were investigated using ATR-FTIR, ESCA, SEM, and dynamic contact angle measurements. Sulfonations using propane sultone were performed directly onto PU or onto hydrophobic dodecanediol (DDO) grafted PU or onto hydrophilic poly(ethyleneoxide) (PEO) grafted PU. ESCA data coincided well with ATR-IR results, as more 0 at. % for PEO grafted PUs and the presence of S for the sulfonated PUs were revealed. At SEM observation the surfaces of PU-DDO and PU-PEO were relatively smooth, whereas all the sulfonated PU surfaces showed excellent smoothness and homogeneity. The hydrophilicity of the surfaces was considerably increased after PEO grafting or sulfonation. In addition, all the sulfonated PU surfaces, particularly PU-PEO-SO3, which has further hydrophilicity, exhibited complete wetting behavior due to the negatively charged SO3 groups.
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PMID:Preparation and surface properties of PEO-sulfonate grafted polyurethanes for enhanced blood compatibility. 828 Jun 72

A plasma polymerized HEMA (ppHEMA) film was prepared by plasma deposition polymerization onto an elastic material, silicone rubber. The surfaces of control, argon plasma-treated, and ppHEMA-modified silicone rubber were characterized by ESCA, FTIR-ATR and SEM techniques. ESCA verified the respective chemical shift of control and ppHEMA-modified films. The presence of the ppHEMA was also verified by ESCA. The introduction of ppHEMA onto a hydrophobic support provided an adequate surface for rabbit corneal epithelial cell attachment and growth. Cell attachment and growth onto these surfaces were examined by light microscopy. Cell attachment onto the control and the argon plasma-treated surface was negligible, while improved attachment and growth of rabbit corneal epithelium cells was demonstrated on the ppHEMA-modified polymeric surface. The ppHEMA-modified silicone rubber surface demonstrated a confluent cell layer after 72 h.
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PMID:ppHEMA-modified silicone rubber film towards improving rabbit corneal epithelial cell attachment and growth. 839 52

Adhesion characteristics of fibroblastic baby hamster kidney (BHK) cells and epithelial Madine Darby kidney (MDBK) cells on polyurethane (PU) and polyhydroxyethylmethacrylate (PHEMA) based surfaces have been studied. PU surfaces were prepared by a classical solvent-casting procedure of Pellethane solution that contains different types of solvents, i.e., THF, dioxane and their compositions. PHEMA based surfaces were obtained by bulk polymerization of respective comonomers (HEMA, acrylic acid, AA, and dimethylaminoethylmethacrylate, DMAEMA) in the presence of the crosslinker. Thus, a number of polymeric surfaces were obtained with different surface charges (COO- and NH+4) and with different surface free energies in a range between 60-82 ergs/cm2. Surface properties of these membranes were characterized by equilibrium water contents, air and octane contact angles, surface free energies, SEM photographs and ATR-FTIR spectra. Interactions of BHK and MDBK cells with the surfaces were examined in stationary culture conditions which were carried out in MEM supplemented with fetal calf serum. The observations strongly suggested that the chemical and/or physical properties of membrane surface and morphology of the cell control the degree of cell adhesion to the PU and PHEMA based membranes.
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PMID:Relationship of surface characteristics to cellular attachment in PU and PHEMA. 845 35

Three hyaluronic acid derivatives with different types and/or percentages of esterification, were analyzed by means of static contact angle measurements, SEM, ESCA, ATR/FT-IR, WAXS, DSC and TGA. The physico-chemical characterization of the three different samples, in both dry and wet state, was provided in terms of surface and bulk properties. ESCA and infrared analyses showed that the surface composition of all samples differs from that of the bulk. The hydrophilic-hydrophobic character of the samples changed according to the chemical composition as shown by ESCA and contact angle measurements. Both infrared and contact angle measurements reveal that surface restructuring occurred upon hydration for all the samples and the greater the hydrophilic character of the sample, the greater and faster the restructuring phenomenon. A clear picture of the different types of chemical groups has been established at different depth for the three materials.
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PMID:Physico-chemical surface characterization of hyaluronic acid derivatives as a new class of biomaterials. 847 94

Cellular interaction and platelet adsorption were investigated on poly(ethylene oxide) (PEO) immobilized silicone rubber membrane (SR) which has polyacrylic acid grafts on the surfaces. Polyacrylic acid (PAA) had been introduced to the SR surface after Ar plasma treatment of SR surfaces to introduce peroxide groups. Surface characterizations were made using ATR-FTIR, ESCA, SEM, and contact angle measurements. Experimental results obtained by ESCA high resolution curve fitting spectra indicated that the amount of bisamino PEO of different molecular weights immobilized onto SR surfaces were similar, which showed that the influence of the length of molecular chains (-C-C-O-) on the reactivity of terminal amino group is negligible. The wettability of modified SR surfaces increased with an increase in PEO molecular weight. Biological studies such as corneal epithelial cell culture and blood platelet adhesion were performed to understand the biocompatibility of modified SR surfaces. Biological studies using corneal epithelial cells showed that cell migration, attachment and proliferation onto PEO-20000 immobilized SR surface were suppressed, whereas these biological activities on PEO-600 were enhanced. Another study on platelet adhesion revealed that many platelets attached to PEO-600 immobilized SR, while platelet deposition was rarely observed on SR grafted with PEO-3350. The effects of different PEO molecular chains on biological response were discussed.
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PMID:Platelet adhesion and cellular interaction with poly(ethylene oxide) immobilized onto silicone rubber membrane surfaces. 883 31


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