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At least 19 recordsLinked to original sources
PubMed1996

Incorporation of a fluorocarbon polymer implanted at the posterior surface of the rabbit cornea.

An implant of porous expanded polytetrafluoroethylene (PTFE) in the corneal stroma allows fast cell colonization and can become translucent. We studied the behavior of the same polymer implanted in the anterior chamber of the rabbit eye and sutured to the posterior surface of the cornea. The expanded tetrafluoroethylene was provided as 200-micron thick sheets in 3 pore diameters (20, 50 and 80 microns). Disks (5 mm) were implanted in the anterior chambers of 20 rabbits and sutured to the posterior surface of the cornea. Histological and ultrastructural studies were performed after 3 and 4 months. Quantimetry was done on TEM images to analyze the fibrillar structure of the intercellular matrix inside and around the implanted polymer. The material was well tolerated. In all cases there was mild central corneal edema, which disappeared after 1 month. Mild neovascularization occurred in five cases, decreasing after 1 month. The polymer became translucent after 8 days. Keratocytes from the corneal stroma colonized the implant via breaks in the Descemet's membrane along the sutures. Quantimetry showed three types of fibrils inside and beside the polymer. Corneal endothelial cells regenerated over the fibroblasts and the polymer. This fluorocarbon polymer implanted in the anterior chamber and sutured to the posterior surface of the cornea was well tolerated, and there was real incorporation, with keratocytes producing collagen fibrils inside the polymer and endothelial cells forming a posterior cell monolayer. This is promising for the development of a keratoprothesis with posterior fixation.

Animals↗
PubMed1990

Plasma gas discharge deposited fluorocarbon polymers exhibit reduced elutability of adsorbed albumin and fibrinogen.

The adsorption and subsequent detergent elutability of fibrinogen and albumin were measured on various treated and untreated polymer films in order to determine whether the relative adsorption of these proteins was responsible for the enhanced thromboresistance of Dacron vascular grafts treated with tetrafluoroethylene in a radio frequency glow discharge (RFGD) apparatus. Fluorocarbon-coated surfaces varying in the relative proportions of CF, CF2, and CF3 groups and in the ratio of fluorine to carbon were prepared by RFGD treatment of poly(ethylene terephthalate) (PET) films with tetrafluoroethylene or perfluoropropane. The adsorption of fibrinogen and albumin to these fluorocarbon-coated surfaces was comparable to the adsorption of the proteins to polytetrafluoroethylene (PTFE) and PET. However, the elutability of fibrinogen and albumin from the RFGD fluorocarbon surfaces with sodium dodecyl sulfate was much lower than that from PTFE or PET. Other RFGD treatments of PET, such as ethylene deposition or argon etching, did not reduce the extent of albumin elutability as dramatically as did the RFGD fluorocarbon treatments. The strong albumin binding to RFGD fluorocarbon surfaces may be exploited clinically to enhance the retention of albumin preadsorbed to blood-contacting surfaces to render them thromboresistant.

Adsorption↗
PubMed2004

Platelet adhesion to radiofrequency glow-discharge-deposited fluorocarbon polymers preadsorbed with selectively depleted plasmas show the primary role of fibrinogen.

Fluorocarbon radio-frequency glow-discharge (RFGD) treatment has previously been shown to cause decreased platelet adhesion despite the presence of adsorbed fibrinogen on the surfaces. In this study platelet adhesion to fluorocarbon RFGD-treated surfaces preadsorbed with human plasma was further examined. A series of plasma deposited fluorocarbon thin films were made by varying the C3F6/CH4 ratio in the monomer feed. The surfaces were preadsorbed with plasma, serum, or plasma selectively depleted of fibronectin, vitronectin, or Von Willebrand factor, and platelet adhesion was measured. We also measured fibrinogen adsorption to the surfaces from plasma, monoclonal antibody binding to adsorbed fibrinogen and SDS elutability of the adsorbed fibrinogen. The antibodies used bind to the three putative platelet binding sites on fibrinogen, namely, M1 antibody binds to the dodecapeptide at the C-terminus of the gamma chain, gamma (402-411), R1 antibody binds to a sequence in the Aalpha chain (87-100) which includes RGDF at Aalpha (95-98) and R2 antibody binds a sequence in the Aalpha chain (566-580) which includes RGDS at Aalpha (572-575). Fibrinogen was found to play a decisive role in mediating platelet adhesion to the fluorocarbon surfaces contacting plasma. Few platelets adhered to the fluorocarbon surfaces preadsorbed with serum, while preadsorption with plasma selectively-depleted of either fibronectin, vitronectin, or von Willebrand factor did not decrease platelet adhesion significantly. Replenishment of exogenous fibrinogen to serum restored platelet adhesion, while replenishment of the other proteins had no effect. Platelet adhesion to the fluorocarbon surfaces was lower than to PET or the methane glow-discharge-treated PET. However, there was no apparent correlation between platelet adhesion and the amount of fibrinogen adsorption or monoclonal antibody binding to surface-bound fibrinogen.

Adsorption↗
PubMed2003

Coatings based on side-chain ether-linked poly(ethylene glycol) and fluorocarbon polymers for the control of marine biofouling.

The preparation of side group modified polystyrene-based surface-active block copolymers (SABC) for use as marine fouling resistance/release applications is described. Modifying moieties such as poly(ethylene glycol) (PEG) and semifluorinated segments were used. A novel bilayer methodology has been employed that provides both suitable mechanical properties through the use of an elastomeric primer layer of styrene-ethylene/butylene-styrene (SEBS) and control of surface-chemistry through use of the SABCs. This approach has potential as a cost-effective technology for environmentally benign coatings that resist and release marine biofouling. Initial testing of these materials included determination of captive bubble contact angles and protein adsorption. Testing against marine fouling organisms was performed using settlement and adhesion bioassays with zoospores of the green alga Enteromorpha. The results showed that all surfaces had markedly reduced levels of zoospore settlement compared with glass controls and that adhesion strength was strongly affected by the semifluorinated SABC. The results are discussed in terms of surface properties.

Adhesiveness↗
PubMed1996

Collagen synthesized in fluorocarbon polymer implant in the rabbit cornea.

The integration of microporous polymer into tissues is of great interest for the production of keratoprosthetic devices. Our previous studies showed functional differentiated cells and collagen synthesis in the pore of an expanded polytetrafluoroethylene implant. This study identifies and quantifies collagen types synthesized in the implant. Expanded polytetrafluoroethylene polymers were implanted in the rabbit corneas. The collagen extracted from the polymer and implanted stroma after 1, 3 and 6 months was quantified by measuring hydroxyproline. The relative proportions of collagen types were determined by densitometric analysis after SDS-PAGE. The collagen-to-protein ratio in the polymer increased from 0.22 to 0.70 between the first and third month after implantation becoming similar to control cornea. So that of the protein and collagen densities in the polymer and implanted stroma were similar to the control from the third month. The collagen synthesized in the polymer was mainly type I (87%) plus a small amount of type III (8%) 1 month after implantation. The collagen distribution from the third month after implantation was similar to that of the controls and remained constant thereafter in the polymer implant and in the implanted stroma. Immunogold labelling techniques confirmed these results. Implantation of this PTFE disc induced no obvious modification of the corneal stroma, confirming that this polymer is a good interface that is compatible with the native corneal stroma. The keratocytes in this polymer rapidly adopted a corneal phenotype, distinct from the dermal or scaring phenotype as shown by the collagen types produced in the implant.

Animals↗
PubMed2004

Fluorocarbon Surfactant Polymers: Effect of Perfluorocarbon Branch Density on Surface Active Properties.

We describe a series of fluorocarbon surfactant polymers designed for modifying fluorocarbon surfaces such as poly(tetrafluoroethylene). Novel fluorocarbon surfactant polymers poly(N-vinyldextranaldonamide-co-N-vinylperfluoroundecanamide), in which hydrophilic dextran oligosaccharides and hydrophobic perfluoroundecanoyl groups were incorporated sequentially onto a poly(vinylamine) backbone, were synthesized and characterized by FT-IR, NMR, and XPS spectroscopy. By adjusting the feed ratio of dextran to fluorocarbon branches, surfactant polymers with different hydrophilic/hydrophobic balances were prepared. The surface activity of the surfactants at the air/water interface was demonstrated by significant reductions in water surface tension. Surfactant adsorption and adhesion at the solid PTFE/aqueous interface were examined under well-defined dynamic flow conditions, using a rotating disk system. The surface activity at the air/water interface and adhesion stability on PTFE under an applied shear stress both increase with increasing density of fluorocarbon branches on the polymer backbone. The results show that stable surfactant adhesion on PTFE can be achieved by adjusting the hydrophilic dextran to hydrophobic fluorocarbon branch ratio.

Journal Article↗
PubMed1998

In vivo study of a fluorocarbon polymer-coated intraocular lens in a rabbit model.

PURPOSE: To evaluate the biocompatibility in rabbit eyes of poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) that were surface modified using Teflon AF. SETTING: Hôtel-Dieu Hospital, Paris Cedex, France. METHODS: The IOLs were coated with Teflon AF, an amorphous, transparent, and highly hydrophobic fluorocarbon polymer, by immersing them in Teflon AF 5% and evaporating the solvent (C8F18). The surface quality of the Teflon-coated IOLs was evaluated by scanning electron microscopy (SEM). Teflon-coated (n = 20) and control PMMA (n = 10) IOLs were implanted in rabbit eyes. The presence of iris-IOL synechias and the number of deposits on the IOL surfaces were clinically evaluated in both groups to assess the antiadhesive effect of Teflon AF. The Teflon-coated IOLs were removed, their surfaces were evaluated by SEM, and their elemental composition was checked by EDXA and Raman spectrometry. RESULTS: The PMMA IOLs were completely coated with Teflon AF. The Teflon group had no iris-IOL synechias and the control group, two extensive synechias. There were significantly fewer deposits on the surfaces of Teflon-coated IOLs than on the control IOLs 30 and 60 days postoperatively (P < .0001). Scanning electron microscopy showed lens epithelium proliferation and spindle-shaped cells on the surfaces of the PMMA IOLs and cell deposits on the irregular regions of the Teflon-coated IOLs. White-yellow spots were present on the surfaces of both IOL types. The elemental composition of Teflon-coated IOLs was stable. CONCLUSION: Teflon AF had an antiadhesive effect that increased the biocompatibility of PMMA IOLs in vivo.

Adhesiveness↗
PubMedDate not supplied

Acute noncardiogenic pulmonary edema due to polymer fume fever.

BACKGROUND: Certain fluorocarbon polymers can produce a clinical syndrome called polymer fume fever when the products of pyrolysis are inhaled. SUMMARY: A previously healthy 21-year-old white man presented with severe chest tightness, difficulty in breathing, pyrexia, nausea, vomiting, and a dry irritating cough. These symptoms occurred suddenly while smoking a cigarette 2 hours after leaving his place of work, where he is a plastics machinist. A chest roentgenogram revealed a bilateral patchy alveolar air space filling pattern involving the mid and lower lung fields. The diagnosis of polymer fume fever was established on the basis of the symptom complex, the association with cigarette smoking, and the occupational exposure to micronized polytetrafluoroethylene. CONCLUSIONS: A thorough occupational and smoking history is necessary to recognize polymer fume disease, which may resemble influenza.

Acute Disease↗
PubMedDate not supplied

Development of methods for skin barrier peeling tests.

OBJECTIVE: We sought to develop a more effective method to evaluate the adhesive properties of skin barriers. DESIGN: The experimental design used was based on 3 principles: partial control, randomization, and repetition. Using these principles, the 180-degree peeling tests were conducted as specified in a standardized methodology (JIS Z0297) to the extent possible. However, the use of a stainless steel plate as a proxy for skin barrier application may result in the stretching and breaking of the skin barrier, making it impossible to obtain suitable measurements. INSTRUMENTS: Tests were conducted in constant temperature/ humidity chambers using a Tensilon Automatic Elongation Tester, where a sample was fixed on the side of a sample immobilization device, a sturdy metal (aluminum) box from which the air in the box was drawn off with a vacuum pump. METHODS: A fluorocarbon polymer film was applied to the adhesive surface of a sample skin barrier. The film was peeled off in the volte-face (180-degree) direction in order to measure adhesive strengths. RESULTS: The films exhibit such properties as (a) ease of removal from the adhesive surface, (b) no resistance to a 180-degree fold back due to the thinness and flexibility of the material, and (c) tolerance of elongation. The adhesive properties of skin barriers were measured by peeling the fluorocarbon polymers in a 180-degree direction. Twelve specimen skin barrier products were selected for measurement, providing results with satisfactory reproducibility. Results based on the conventional stainless steel plate-based testing method acted as a control. CONCLUSION: The newly developed testing method enables chronological measurement results for skin barriers applied to fluorocarbon polymer films after 24 hours, 48 hours, and longer period.

Adhesiveness↗
PubMed1996

[Artificial cornea].

The cornea is the anterior transparent hole of the eye and its replacement by a synthetic material proves indispensable in some kinds of corneal blindness when penetrating keratoplasty is impossible. For a long time, the keratoprosthesis have been developed by different authors but results were always disappointing. Our personal works have been centered on the utilization of an expanded fluorocarbon polymer as interface between the optic of the keratoprosthesis and the cornea of the recipient. This material has given us a lot of satisfactions but our prosthesis did not meet the criteria of a real artificial cornea because the rigid optic induced mechanical tolerance problems and did not allow the measure of the intraocular pressure. We have developed a new model of artificial cornea with a soft optical zone with a diameter of 6 mm and an haptic made of expanded fluorocarbon polymer pretreated in order to induce a fast cellular ingrowth. We hope that this new optical device could improve optical results and tolerance.

Cornea↗
PubMed1980

Fever induced by fluorine-containing lubricant on stainless steel tubes.

Three subjects, all smokers, handling stainless steel tubes suffered repeated attacks of general malaise, chills, and fever lasting for several hours, mainly after gas soldering. Provocations by rubbing smoking tobacco against a tube produced similar attacks, and leucocytosis, after a few hours. The presence of fluorine on the tubes and in the febrifacient tobacco was shown. A fluorocarbon polymer lubricant was suspected of causing the attacks. Heating (1000 degrees C) of the tubes eliminated the effect.

Adult↗
PubMed1992

A new fluorocarbon for keratoprosthesis.

Previous studies have demonstrated the potential use of microporous, biocompatible materials to improve the long-term stability of keratoprosthesis. To determine the factors that will influence corneal tissue ingrowth into biocompatible, microporous materials, we have compared three types of fluorocarbon polymers--Impra, Gore-Tex, and Proplast--after intrastromal implantation in rabbit corneas. Despite similar physicochemical structures, a great difference was observed in histologic and ultrastructural cross sections after 4- and 8-month follow-ups. For Gore-Tex, we observed extrusion of the implant and infiltration of necrotic and inflammatory cells. All implants of Proplast also led to significant corneal damage resulting in extrusion of the material. Through the use of electron and light microscopy and image analysis, this study demonstrates the presence of cell differentiation and collagen synthesis in the pores of the Impra implant. Apart from biocompatibility, this experiment demonstrates the influence of pore size, porous microorganization, and biomechanical factors on prosthetic corneal material. Only Impra offers satisfactory interface, allowing fibroblastic cells and neocollagen synthesis into its pores, and it can become transparent.

Animals↗