Plasma graft polymerization of Acrylic Acid and immobilization of Heparin to improve blood compatibility of Polyethylene terephthalate (PET) (original) (raw)
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Poly (ethylene terephthalate) (PET) was surface modified by plasma polymerization of acetobromo-aD glucose (ABG) at different radio frequency (RF) powers. Plasma polymerization was carried out by vaporizing ABG in the powder form by heating at 1358C. Surface modification resulted in improved hydrophilicity and smoothness of the surface especially at low RF powers (30–50 W), but at high RF powers, the surface was found to be etched and the hydrophilicity decreased as evidenced by atomic force microscopy (AFM) and contact angle measurements. The plasma polymerized ABG film was found to be extensively cross-linked as evidenced by its insolubility in water.
Blood compatibility of hydrophilic polymers
Journal of Biomedical Materials Research, 1981
Blood compatibility has been studied for hydrophilic polymers such as poly(viny1 alcohol) (PVA), its derivative, and polyethylene grafted with water-soluble monomers. The surfaces in contact with electrolyte solutions have been characterized by measuring the zeta potentials. The study of plasma protein adsorption on these polymers has revealed that bovine serum albumin as well as bovine serum fibrinogen adsorbs to a lesser extent as the hydrophilicity of the polymers increases. Platelet deposition and fibrin formation, examined using platelet-rich plasma, have been found to take place less significantly on PVA as well as sodium acrylate-and acrylamide-grafted polyethylene than on nongrafted and acrylic acid-grafted polyethylene. Ex uirm experiments with canine whole blood have shown that formation of thrombus on PVA is less than on siliconized glass but increases upon heat treatment which reduces the hydrophilicity. When PVA tubes of about I mm diameter are anastomosed to the carotid artery of rat, the patency rate is found to depend strongly on the anastomotic technique. From the results on the zeta potential and the experiments in vitro and ex vivo it can be concluded that the material having a surface from which solvated, neutral chains are extended into the outer aqueous phase may exhibit excellent resistance to thrombus formation.
Covalent Binding of Heparin to Functionalized PET Materials for Improved Haemocompatibility
Materials, 2015
The hemocompatibility of vascular grafts made from poly(ethylene terephthalate) (PET) is insufficient due to the rapid adhesion and activation of blood platelets that occur upon incubation with whole blood. PET polymer was treated with NHx radicals created by passing ammonia through gaseous plasma formed by a microwave discharge, which allowed for functionalization with amino groups. X-ray photoelectron spectroscopy characterization using derivatization with 4-chlorobenzaldehyde indicated that approximately 4% of the-NH2 groups were associated with the PET surface after treatment with the gaseous radicals. The functionalized polymers were coated with an ultra-thin layer of heparin and incubated with fresh blood. The free-hemoglobin technique, which is based on the haemolysis of erythrocytes, indicated improved hemocompatibility, which was confirmed by imaging the samples using confocal optical microscopy. A significant decrease in number of adhered platelets was observed on such samples. Proliferation of both human umbilical vein endothelial cells and human microvascular endothelial cells was enhanced on treated polymers,
Materials Research, 2010
In devices used in open-heart surgery and dialysis, blood must be continuously processed using extracorporeal circuits composed of peristaltic pumps and active components such as specific filters and oxygenators. Several procedures have been employed to avoid blood coagulation induced by contact with the artificial surfaces of such devices. Often heparin, a bioactive protein able to prevent clot formation, is employed. In this work, we have used heparin-containing gas plasmas to evaluate the possibility of depositing adherent anticoagulant films onto PVC and glass surfaces. The films were produced by radiofrequency plasma enhanced chemical vapor deposition from heparin/isopropanol and heparin/hexamethyldisiloxane solutions. In addition, the effects of exposure to SF 6 plasmas on the compatibility of such surfaces have also been investigated. The blood compatibility was evaluated through the determination of the density of platelets and fibrinogen and activated partial thromboplastin (APTT) and prothrombin times (PT) of human blood freshly collected and after contact for 2.5 hours with different surfaces. The deposited films were also characterized by infrared spectroscopy, contact angle and surface energy measurements. The coagulation time of blood, placed in contact with glass substrates coated by PECVD films of heparin/isopropanol mixtures, and in contact with SF 6 plasma-treated PVC, increased by about 60 and 20%, respectively, compared to the values measured with untreated samples.
Hemocompatible Poly(ethylene terephthalate) Polymer Modified via Reactive Plasma Treatment
Japanese Journal of Applied Physics, 2011
In this paper we present the fabrication of micro-and nanostructure poly(ethylene terephthalate) (PET) polymer surfaces used for as synthetic vascular grafts and their hemocompatible response to plasma-treated surfaces. The surface modification of PET polymer was performed using radio frequency (RF) weakly ionized and highly dissociated oxygen or nitrogen plasma. The surface of the PET polymer was modified to enable the improved proliferation of endothelial cells. In addition to biological experiments performed in vitro by assessing the number of attached cells by tetrazolium compound (MTS)-based cell proliferation assay, we also analyzed the chemical modification of plasma-treated surfaces by X-ray photoelectron spectroscopy (XPS), while the changes in morphology and surface roughness were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Our results indicate that surface treatment with both oxygen and nitrogen plasma improved the proliferation of endothelial cells, which increased with treatment time by 15 to 30%. This phenomenon was explained by the creation of new functional groups and the modification of surface morphology, which promotes the adhesion of endothelial cells.
Surface Modification of Polymeric Materials and its Effect on Blood Compatibility
MRS Proceedings, 1987
The surfaces of commercially available polymeric materials have been modified through two techniques, the chemical infusion process and physical vapor deposition. The surfaces of poly(methylmethacrylate) (PMMA) have been modified through a chemical infusion process by treatment of the sample with a solution containing varying amounts of titanium(IV)isopropoxide and polyvinylpyrrolidone (PVP). The surfaces of silicone rubber samples have been coated with a thin coating of titanium dioxide with an ion beam sputtering technique. The treated samples were characterized by scanning electron microscopy, optical microscopy, and neutron activation analysis. The infused samples were evaluated for blood compatibility using two biological assays: 1) an adherence assay in which the adherence of human polymorphonuclear leukocytes to the samples was determined, and 2) a hemolysis assay using rat blood erythrocytes to determine the hemolytic activity of the samples. Based on the results of these as...
Plasma-induced graft-polymerization of polyethylene glycol acrylate on polypropylene substrates
The European Physical Journal D, 2009
This work deals with the optimization of argon plasma-induced graft-polymerization of polyethylene glycol acrylate (PEGA) on polypropylene (PP) films in order to obtain surfaces with a reduced protein adsorption for possible biomedical applications. To this end, we examined the protein adsorption on the treated and untreated surfaces. The graft-polymerization process consisted of four steps: (a) plasma pre-activation of the PP substrates; (b) immersion in a PEGA solution; (c) argon plasma-induced graftpolymerization; (d) washing and drying of the samples. The efficiency of these processes was evaluated in terms of the amount of grafted polymer, coverage uniformity and substrates wettability. The process was monitored by contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM) analyses. The stability of the obtained thin films was evaluated in water and in Phosphate Buffer Saline (PBS) at 37°C. The adsorption of fibrinogen and green fluorescent protein (GFP) -taken as model proteins -on the differently prepared surfaces was evaluated through a fluorescence approach using laser scanning confocal microscopy with photon counting detection. After plasma treatments of short duration, the protein adsorption decreases by about 60-70% with respect to that of the untreated film, while long plasma exposure resulted in a higher protein adsorption, due to damaging of the grafted polymer.
Plasma induced graft polymerization of acrylic acid onto poly (ethylene terephthalate) monofilament
Indian Journal of Fibre and Textile Research
The graft polymerization of acrylic acid has been carried out on poly(ethylene terephthalate) (PET) monofilament to introduce carboxylic acid groups. The filament is treated with oxygen plasma for the introduction of peroxides and subsequently grafted with acrylic acid. The influence of monomer concentration, plasma exposure time and reaction temperature on the degree of grafting has been investigated. The grafted filament is subsequently immobilized with chitosan. ATR-FTIR confirms the immobilization of chitosan. The contact angle decreases from 72° for virgin PET to 38° for 180s plasma exposured sample, 42° for the grafted and 36° for the chitosan immobilized sample which shows significant improvement in the wettability. The surface topography of filaments is characterized by atomic force microscopy.
Surface Engineering, 2012
The aim of this study is to design an artificial skin dress. A multilayer skin dressing included synthesised castor oil based polyurethane (PU) as the outer layer and two biopolymeric layers of heparin and chitosan as the inner layers were prepared. The surface of PU film was activated using two steps oxygen radio frequency plasma treatment. The surface of the modified PU films characterised by attenuated total reflection Fourier transform infrared spectroscopy, scanning electron microscopy and water drop contact angle measurements. Scanning electron microscopy observations confirmed the presence of grafted poly acrylic acid on the surface of PU films. Also, heparin and chitosan were immobilised on PU films. In vitro cell culture showed that the samples have an excellent biocompatibility with L929 fibroblast cells. Cell adhesion and proliferation of cells on the chitosan/heparin immobilised surfaces showed better behaviours compared with poly (acrylic acid) grafted PU film.
Journal of Colloid and Interface Science, 2010
This work deals with the optimization of argon plasma-induced graft-polymerization of polyethylene glycol acrylate (PEGA) on polypropylene (PP) films in order to obtain surfaces with a reduced protein adsorption for possible biomedical applications. To this end, we examined the protein adsorption on the treated and untreated surfaces. The graft-polymerization process consisted of four steps: (a) plasma pre-activation of the PP substrates; (b) immersion in a PEGA solution; (c) argon plasma-induced graftpolymerization; (d) washing and drying of the samples. The efficiency of these processes was evaluated in terms of the amount of grafted polymer, coverage uniformity and substrates wettability. The process was monitored by contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS) and atomic force microscopy (AFM) analyses. The stability of the obtained thin films was evaluated in water and in Phosphate Buffer Saline (PBS) at 37°C. The adsorption of fibrinogen and green fluorescent protein (GFP) -taken as model proteins -on the differently prepared surfaces was evaluated through a fluorescence approach using laser scanning confocal microscopy with photon counting detection. After plasma treatments of short duration, the protein adsorption decreases by about 60-70% with respect to that of the untreated film, while long plasma exposure resulted in a higher protein adsorption, due to damaging of the grafted polymer.