oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Surface Modification of Biomaterials: A Quest for Blood Compatibility  [PDF]
Achala de Mel,Brian G. Cousins,Alexander M. Seifalian
International Journal of Biomaterials , 2012, DOI: 10.1155/2012/707863
Abstract: Cardiovascular implants must resist thrombosis and intimal hyperplasia to maintain patency. These implants when in contact with blood face a challenge to oppose the natural coagulation process that becomes activated. Surface protein adsorption and their relevant 3D confirmation greatly determine the degree of blood compatibility. A great deal of research efforts are attributed towards realising such a surface, which comprise of a range of methods on surface modification. Surface modification methods can be broadly categorized as physicochemical modifications and biological modifications. These modifications aim to modulate platelet responses directly through modulation of thrombogenic proteins or by inducing antithrombogenic biomolecules that can be biofunctionalised onto surfaces or through inducing an active endothelium. Nanotechnology is recognising a great role in such surface modification of cardiovascular implants through biofunctionalisation of polymers and peptides in nanocomposites and through nanofabrication of polymers which will pave the way for finding a closer blood match through haemostasis when developing cardiovascular implants with a greater degree of patency. 1. Introduction Cardiovascular disease accounts for a significant percentage of mortality and morbidity in the ageing population and has an estimated increase in the coming years [1]. There is an urgent clinical need for improved cardiovascular devices, which mainly include vascular bypass grafts, vascular stents, and heart valves, which will promote desirable blood-biomaterial interactions with a high patency. Vascular occlusive disease holds the greatest risk factor most emphasised in the coronary arteries where cardiac ischemia may lead to complete heart failure. Main reperfusion-based surgical intervention options for these diseases involve angioplasty, stenting, endarterectomy, and bypass graft surgery depending on the degree of occlusion. Cases with greater than 70% occluded arteries are required to be treated with bypass grafts. For small diameter bypass grafts, autologous bypass conduits are preferred for primary revascularisation [2]. However, 3–30% patients are presented with no autologous vessels due to previous disease conditions and thus there is a need for vascular grafts which could perform closely to autologous vessels [3]. Graft thrombogenicity due to material surface incompatibility and altered flow dynamics at the site of anastomosis or distal outflow are recognised as primary reasons for blood contacting device failure [4]. There is a great interest in
SURFACE CHARACTERIZATION OF BLENDED POLY(ETHER-ESTER) MULTIBLOCK COPOLY-MER AND ITS BLOOD COMPATIBILITY
共混合聚(醚-酯)多嵌段共聚物的表面表征及其血液相容性研究

JI Ke-jian,WANG Jian-qi,LI Xue-fen,CHEN Chuan-fu,
冀克俭
,王建祺,李学芬,陈传福

高分子学报 , 1990,
Abstract: By using X-ray photoelectron spectroscopy (XPS), surface contact angle, surface potential and blood compatibility, the relationship between the composition and property of the surface and the blood compatibility of poly (ether-ester) multiblock copolymer and its blend has been studied. Experimental results indicated that the blood compatibility was very bad and bore no relation to the enrichment of PTMO soft segment in the surface phase for hydrophobic PET-PTMO multiblock copolymers. In the mixture of hydrophobic PET-PTMO and hydrophilic PET-PEO, an optimum blended proportion was found. The platelet adhering to the material surface conside-rably decreased at the optimum.and surface potential couldbe better correlated with the blood compatibility in the blends. The above results showed clearly that the hydrophilic and hydrophobic balance, the distribution of the soft segment in the depth and potential of the material surfaces were important factors affecting blood compatibility.
Effect of micromagnetic field surface roughness of 316L stainless steel and NiTi alloy on blood compatibility
316L不锈钢和NiTi合金微磁场表面粗糙度对血液相容性的影响

LIU Qiang CHENG Xiaonong XU Hongxing FEI Huangxia,
刘强
,程晓农,徐红星,费黄霞

材料研究学报 , 2009,
Abstract: To reducing surface roughness, TiO2 film with different lay numbers was coated on the TiO2 film containing SrFe12O19 powder on the surface of NiTi alloy and 316L stainless steel with sol-gel method. The surface roughness of these films were investigated by SEM and surface roughometer, and the dynamic clotting time and hemolysis rate of these different roughness micromagnetic field surfaces were tested. The results showed that the blood compatibility on the micromagnetic field surface with low roughness is better, that is, smoother micromagnetic field surface can be used to further improve the blood compatibility of the materials.
Blood protein adsorption and compatibility studies of gold nanoparticles
N. Nimi,Willi Paul,Chandra P. Sharma
Gold Bulletin , 2011, DOI: 10.1007/s13404-010-0001-6
Abstract: Gold nanoparticles are considered to be real jewels. The significant growth of their application for labeling, delivery, heating, and sensing shows their significance in biology and/or life sciences. PEGylated gold nanoparticles also have significant application in drug and gene delivery. However, comprehensive information on the compatibility of these nanoparticles to blood is limited in literature. An attempt has been made to study the protein adsorption, blood cell aggregation, and C3 adsorption onto these particles to evaluate its complement activation potential and blood compatibility. It has been observed that these nanoparticles do not induce any complement activation or blood cell aggregation. Particles were non-hemolytic and the adsorptions of proteins were negligible which further validates its significance in drug delivery and gene delivery applications.
Evaluation of blood compatibility of plasma deposited heparin-like films and SF6 plasma treated surfaces
Perrenoud, Ivanira Antunes;Rangel, Elidiane Cipriano;Mota, Rogério Pinto;Durrant, Steven Frederick;Cruz, Nilson Cristino da;
Materials Research , 2010, DOI: 10.1590/S1516-14392010000100019
Abstract: 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 sf6 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 sf6 plasma-treated pvc, increased by about 60 and 20%, respectively, compared to the values measured with untreated samples.
The preparation and blood compatibility of pure iron thin film using filter cathode vacuum arc

Sheng-Fa ZHU,

材料研究学报 , 2008,
Abstract: Iron thin film were deposited on silicon substrate using filter cathode vacuum arc. Composition and valence studies were carried out by X-ray photoelectron spectroscopy (XPS); Glancing angle X-ray diffraction (GAXRD) was employed to examine the phase structure. In vitro blood compatibility tests, including platelet adherent, prothrombin time(PT) and thrombin time(TT), were used to evaluate the antithrombogenic properties. Scanning electron microscopy (SEM) and optical microscopy were employed to evaluate the surface morphology of the blood platelets on the films. The results have shown that the number of adherent platelets, the aggregation and pseudopodium were reduced compared to that observed on the 316L stainless steel. The PT and TT for iron thin films are almost the same as for the original plasma, which indicates that the tendency for activating blood coagulation factors is very slight.
Study on Mechanical Properties and Blood Compatibility of Carbon Nitride Film Deposited on NiTi Alloy
LIU Min,WANG Ji-Gang
无机材料学报 , 2009, DOI: 10.3724/sp.j.1077.2009.00491
Abstract: Ti/CNx (x .26), as well as Ti/DLC (Diamond-Like Carbon) and Ti/TiN gradient films were deposited on NiTi alloy substrates using DC (direct current) magnetron sputtering method. The mechanical properties concerning hardness and cohesion of the above three films were tested by using microhardness tester and scratch tester, respectively. The surface hydrophilicities of the three films were measured using contact angle measurement. The blood compatibilities of the substrate and the films were evaluated by hemolysis test and platelet adhesion test. The results indicate that the cohesion between Ti/CNx film and NiTi alloy substrate is excellent (63.6N). The hardness of the CNx film (23.01GPa) is nearly equal to that of the TiN film, which is somewhat higher than that of the DLC films. The results of surface hydrophilicity test and platelet adhesion test demonstrate that the hydrophilicity and blood compatibility of NiTi alloy are improved effectively by the modification with the Ti/CNx film. In comparison with Ti/TiN and Ti/DLC gradient films, Ti/CNx film has the minimum hemolysis ratio of 1.12%. Among the above gradient films, the Ti/CNx film has the best blood compatibilities, as indicated by the minimum amount of conglutinated platelets and the least deformation.
Synthesis and blood compatibility of rutile-type titanium oxide coated LTI-carbon
Feng Zhang,Yu Chen,Zhihong Zheng,Nan Huang,Xianghuai Liu,Anqing Chen,Zhenbin Jiang
Science China Life Sciences , 1998, DOI: 10.1007/BF02882740
Abstract: Titanium oxide films were synthesized by ion beam enhanced deposition, where the films were prepared by depositing titanium atoms and simultaneously bombarding with Xe+ ions at an energy of 40 keV in an O2 environment. The titanium oxide films exhibit rutile-type structure with (100) orientation and the O/Ti ratio is about 2:1. Ti2+, Ti3+ and Ti4+ coexist in the films.In vitro andin vivo investigations were used to investigate the blood compatibility of titanium oxide films. The results show that the blood compatibility of rutile-type titanium oxide fi is better than that of low temperature isotropic pyrolytic carbon (LTI-carbon), which is widely used to fabricate artificial heart valve. It is thought that rutile-type titanium oxide coated LTI-carbon most probably becomes new biomaterial to fabricate artificial heart valves.
Synthesis and blood compatibility of rutile-type titanium oxide coated LTI-carbon

ZHANG Feng,

中国科学C辑(英文版) , 1998,
Abstract: Titanium oxide films were synthesized by ion beam enhanced deposition, where the films were prepared by depositing titanium atoms and simultaneously bombarding with Xe+ ions at an energy of 40 keV in an O2 environment. The titanium oxide films exhibit rutile-type structure with (100) orientation and the O/Ti ratio is about 2:1. Ti2+, Ti3+ and Ti4+ coexist in the films.In vitro andin vivo investigations were used to investigate the blood compatibility of titanium oxide films. The results show that the blood compatibility of rutile-type titanium oxide fi is better than that of low temperature isotropic pyrolytic carbon (LTI-carbon), which is widely used to fabricate artificial heart valve. It is thought that rutile-type titanium oxide coated LTI-carbon most probably becomes new biomaterial to fabricate artificial heart valves. Project supported by the National Natural Science Foundation of China (Grant No. 39200034) and Natural Science Foundation of Shanghai.
Synthesis, characterization and photoinduced curing of polysulfones with (meth)acrylate functionalities  [cached]
Cemil Dizman,Sahin Ates,Lokman Torun,Yusuf Yagci
Beilstein Journal of Organic Chemistry , 2010, DOI: 10.3762/bjoc.6.56
Abstract: The UV-curable telechelic polysulfones with (meth)acrylate functionalities were synthesized by condensation polymerization and subsequent esterification. The final polymers and intermediates at various stages were characterized by 1H NMR, FT-ATR, and GPC. The oligomeric films prepared from the appropriate solutions containing these telechelics and 2,2-dimethoxy-2-phenylacetophenone (DMPA) as the photoinitiator undergo rapid polymerization upon irradiation forming insoluble networks. The photo-curing behavior was investigated by photo-DSC and the effects of the molecular weight of the polysulfone precursor and type of functionality on the rate of polymerization and conversion were evaluated. Thermal properties of the photochemically cured films were studied by differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA).
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.