肝素涂层插管生物相容性评价

对肝素涂层插管和未涂层插管设计了抗凝血、血栓形成观察以及溶血、细胞毒性、炎性和免疫反应等多种试验，从多角度综合对肝素涂层插管材料进行生物相容性评价。通过活化部分凝血活酶时间(APTT)、凝血酶原时间(PT)、纤维蛋白原降解产物(FIB)、凝血酶时间(TT)、血小板活化因子、纤维蛋白吸附等试验，测定样品的体外抗凝血性，然后通过半体内血栓形成试验，模拟插管在动物体内的使用环境和过程，观察样品引起血栓形成的状况。同时，通过溶血试验和细胞毒性试验以及炎症反应、补体激活、免疫球蛋白等检测，进一步对样品进行血液相容性评价。结果显示，肝素涂层实验组APTT和TT得到有效延长，而其他体外抗凝指标未见显著变化；在动物半体内模型试验和检测中，肝素涂层实验组6 h血栓形成的各项指标均低于未涂层对照组，表明肝素涂层通过抑制内源性凝血途径达到了预期的抗凝效果；而溶血率、细胞毒性、炎症反应、补体激活、免疫球蛋白等方面的试验结果与未涂层对照组无差异，表明肝素涂层对材料的血液相容性无不良影响。结果表明，肝素涂层显著提高了动静脉插管的体内外抗凝血性，具有良好的生物相容性，可提高临床应用的安全性。     

新型醛基化海藻酸钠-肝素复合涂层的制备及性能评价

研制一种新型基于多醛基海藻酸钠和肝素的复合涂层,并就其生物相容性和血液相容性进行实验和评价.通过高碘酸钠氧化海藻酸及重氮化处理肝素获得多糖分子片段,多糖分子片段通过共价交联固定于体外循环管路表面.通过红外及紫外扫描对固定的多糖分子片段进行定性及定量分析;通过血小板粘附实验及蛋白粘附实验对涂层管道的血液相容性进行评价;通过表面接触角实验评价涂层管路的亲水活性;通过凝血功能检测评价管路表面的抗凝血活性.结果显示:氧化海藻酸及重氮化处理后肝素在在管道表面固定确实;涂层组与未涂层组相比,血小板粘附量及血栓形成量均显著减少(P＜0.05);肝素涂层组(LMNH)组与空白对照(C)组相比,蛋白粘附量无显著差异(P＞0.05);海藻酸钠涂层(OSA)组、双涂层(OSA.LMNH)组与LMNH组相比,蛋白粘附量均显著减少(P ＜0.05);LMNH组、OSA.LMNH组APTT及TT时间均显著延长(P＜0.05),抗凝血性能优良;OSA组与C组相比,APTT时间显著延长(P＜0.05)具有一定的抗凝血性能;OSA组、OSA.LMNH组与C组相比,表面接触角明显减小(P ＜0.05);LMNH组与C组相比,表面接触角无显著差异(P＞0.05).实验结果表明,OSA涂层物具有更优的亲水性和抗蛋白粘附性,LMNH涂层物具有更优的抗凝血性能,多糖片段复合涂层综合了单涂层的优点,生物相容性和血液相容性较单涂层均明显改善.     

聚多巴胺辅助溶胶-凝胶TiO_2薄膜表面固定牛血清白蛋白

在钛表面涂覆溶胶-凝胶TiO2薄膜,再利用聚多巴胺薄膜结合牛血清白蛋白(BSA)分子,以改善血液相容性。X射线光电子能谱分析表明TiO2薄膜表面形成了聚多巴胺薄膜和BSA分子层。接触角测试结果表明聚多巴胺薄膜和BSA分子层使试样的接触角升高,但表面能和界面张力下降。血液相容性实验表明,与TiO2涂层试样相比,结合BSA分子的试样具有更好的抗凝血性能和抗血小板聚集性能。     

新型醛基化海藻酸钠抗凝血涂层物制备及性能评价

应用醛基化海藻酸钠交联涂层体外循环管路,并对涂层管路的血液相容性和生物相容性等性能进行研究和评价。将多醛基的氧化海藻酸钠(OSA),固定到体外循环聚氯乙烯(PVC)管路表面,评价其血液相容性和生物相容性等指标,并与空白对照组(PVCC)和进口产品美敦力肝素涂层组(PVCM)比较。结果表明,OSA涂层物有效固定在PVC管道表面,且OSA涂层管路(PVCS)具有良好的抗凝血性能,仅次于PVCM(P<0.05),显著优于PVCC(P<0.05);PVCS蛋白粘附率显著低于PVCC(P<0.05)和PVCM(P<0.05);PVCS血小板粘附量显著低于PVCC(P<0.05),与PVCM相比无显著差异(P>0.05)。PVCS与PVCM脱落率相比,有着相似的趋势。OSA涂层体外循环管路,具有良好的抗凝血性能、优越的生物相容性和较好的稳定性。     

类金刚石薄膜蛋白吸附与碳相成分关系的定量分析研究

运用灰色系统理论中的 T型关联度分析方法 ,对类金刚石 (DL C)薄膜、富石墨相 DL C薄膜和富金刚石相 DL C薄膜三种 DL C薄膜进行了碳相成分对其白蛋白 (HSA)、纤维蛋白原 (HFG)、免疫球蛋白 (Ig G)三种血浆蛋白吸附量影响的定量分析研究。合理地解释了三种材料蛋白吸附量随碳相成分变化的实验结果 ,并得出如下重要的分析结论 :(1)石墨和 C- H相对 HSA的吸附影响较大 ,随着二者的增加 ,HSA的吸附量下降 ;(2 )与 HFG吸附有较强关联的碳相成分是 DL C相和 C- O相 ,前者呈负相关 ,后者为正相关 ;(3)各碳相成分对 Ig G的吸附均有性质不尽相同的影响 ,但程度有限 ,且彼此间相差不大 ;(4 ) DL C碳相具有增强 HSA吸附、抑制 HFG、Ig G吸附的双重功效 ,其对 DL C薄膜血液相容性的影响远较其它碳相成分更为重要。     

单克隆抗体洗脱性血管内支架的血小板黏附实验

应用扫描电镜(SEM)对镍钛记忆合金血管内支架表面吸附有抗人血小板膜糖蛋白Ⅱb/Ⅲa单克隆抗体的L-聚乳酸(L-PLA)涂层的抗血栓性能做了初步的研究.实验结果显示L-PLA抗体涂层能与支架稳定结合,并发挥抗血小板作用,阻止血小板在支架表面的黏附.L-PLA抗体洗脱性血管内支架是具有更好血液相容性和抗血栓形成双重作用潜力的新型药物洗脱性血管内支架.     

TiO2-x薄膜与热解碳血液相容性的对比研究

本文用血小板粘附试验证实了TiO2-x薄膜具有优于热解碳的血液相容性;并通过对材料表面(界面)能参数与血浆蛋白吸附关系的分析,阐述了两种材料表面蛋白质的不同吸附行为是导致其血液相容性差异的重要原因.     

TiO2-x薄膜与热解碳血液相容性的对比研究

本文用血小板粘附试验证实了TiO2 x薄膜具有优于热解碳的血液相容性 ;并通过对材料表面 (界面 )能参数与血浆蛋白吸附关系的分析 ,阐述了两种材料表面蛋白质的不同吸附行为是导致其血液相容性差异的重要原因。     

新型多醛基海藻酸钠-肝素复合涂层的制备和筛选

背景：前期实验证明多醛基海藻酸钠-肝素复合涂层具有良好生物相容性和血液相容性,但对于最优制备条件和最优模式尚不清楚。 目的：研制一种新型多醛基氧化海藻酸钠-肝素复合涂层,筛选新型涂层制备的最佳条件。 方法：以正交实验筛选氧化海藻酸钠(或肝素)最优涂层条件,获得3种氧化海藻酸钠/肝素复合涂层模式,将复合涂层通过共价交联的方式固定到氨基化预处理/化学修饰的聚氯乙烯管道表面,从涂层物定量、蛋白黏附实验和表面接触角实验3个方面筛选最优复合涂层模式,并检测最优复合涂层的抗凝血性能。 结果与结论：氧化海藻酸钠涂层物最优涂层条件为50%浓硫酸、0.05%聚乙烯亚胺、反应溶液pH值3.5、反应温度为40 ℃和氧化海藻酸钠质量浓度为2 g/L。肝素涂层物最优涂层条件为70%浓硫酸、0.1%聚乙烯亚胺、反应溶液pH值3.5、反应温度为30 ℃和肝素质量浓度为0.1 g/L。复合涂层物最佳涂层模式氧化海藻酸钠、肝素涂层量分别为(4.07±1.35),(2.13±0.24) μg/cm²,此复合涂层具有良好的生物相容性及抗凝血性能。     

动脉微栓过滤器抗凝涂层修饰及生物相容性研究

为研制具有良好生物相容性的新型体外循环动脉微栓过滤器(AF),以化学接枝改性方法制备低分子肝素(LMWH)涂层、部分氧化的海藻酸钠(OSA)涂层的AF用涤纶滤网。利用红外光谱分析表面涂层基团,通过表面接触角测定、蛋白黏附试验、血小板黏附试验、抗凝活性检测、体外血栓形成试验等进行生物相容性评价,通过涂层动态脱落、管路压力、流量检测等评价滤器应用安全性能。结果显示,涂层后材料的红外光谱在涂层物吸收峰处出现变化,表面接触角变小(P<0.01),且OSA组(25.2±4.02)°小于LMWH组(32.7±4.65)°,人血清白蛋白黏附量、纤维蛋白原粘附量显著减少(P<0.05),OSA组黏附(1.63±0.37,1.32±0.14)μg/cm2少于LMWH组(2.56±0.81,2.00±0.32)μg/cm2,血浆接触涂层材料后PT、APTT显著延长,与PET组间差异有统计学意义(P<0.05)。模拟体外转流中约有10%的涂层物脱落,AF进口端压力、跨滤器压力差增加(P<0.01)、流量/转速减少。实验表明,化学接枝改性方法制备的LMWH及OSA涂层滤网,涂层结合稳定,生物相容性提高,满足应用安全需要。与LMWH涂层相比,OSA涂层的抗凝性能略差,但亲水性及对蛋白黏附的改善优于LMWH涂层,可能具有更好的组织相容性,加之OSA低廉的价格,将有更广泛的应用空间。     

Hemocompatibility of titanium oxide films

Hemocompatibility is a key property of biomaterials that come in contact with blood. Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. In this paper, we describe our work of improving hemocompatibility with Ti-O thin films prepared by plasma immersion ion implantation and deposition and by sputtering. The structure and surface chemical and physical properties of the films were characterized by X-ray diffraction, Auger electron spectroscopy, atomic force microscopy (AFM), contact angle measurement, and Hall effect measurement. The behavior of fibrinogen adsorption was investigated by 125I radioactive isotope labeling and AFM. Systematic evaluation of hemocompatibility, including in vitro clotting time, thrombin time, prethrombin time, platelet adhesion, and in vivo implantation into dog's ventral aorta or right auricle from 17 to 90 days, proved that Ti-O films have excellent hemocompatibility. It is suggested that the significantly lower interface tension between Ti-O films and blood and plasma proteins and the semiconducting nature of Ti-O films give them their improved hemocompatibility.     

Albumin and heparin multilayer coatings for blood-contacting medical devices

Three types of covalently crosslinked assemblies consisting of multiple (1) molecular layers of human serum albumin (HSA); (2) alternating layers of HSA and unfractionated heparin; and (3) alternating layers of HSA and partly depolymerized heparin fixed with one end to HSA were prepared on various surfaces. Adsorption of fibrinogen, IgG, and antithrombin (ATIII) from human citrated plasma on coated surfaces was evaluated by ELISA. Fibrinogen adsorption on coated ELISA plates was lower than that on bare polystyrene. There was no IgG adsorption on the HSA coating alone, but considerably high IgG adsorption was detected on the heparin-containing surface. The adsorption of ATIII increased with increasing heparin on the surface. The effect of multilayer coatings on platelets was tested by incubation of modified vascular prostheses with citrated blood. The most favorable interaction with platelets was observed on the HSA assembly. The interaction of platelets with the surface bearing unfractionated heparin was higher than that of the surface covered with partly depolymerized heparin. The long-term durability of the HSA-heparin coating was proven by a 21-day implantation of coated polyurethane plates in goat heart.     

Fabrication of micropored elastomeric film-covered stents and acute-phase performances

To prevent thrombus formation in the acute phase and restenosis in the subacute to chronic phase after stenting of atherosclerotic arteries, we developed a covered stent with a micropored elastomeric film, the blood-contacting surface of which was coated with a photocured gelatin layer immobilized with heparin. Segmented polyurethane (SPU) film (30 microm in wall thickness) as a cover material was multiply micropored by excimer laser-directed microprocessing (pore diameter, 30 microm; interpore distance, 125 microm). An aqueous mixed solution of benzophenone-derivatized gelatin and heparin was coated on the micropored SPU film. Upon ultraviolet light irradiation, a thin layer of a gelatin gel immobilized with heparin was formed and simultaneously fixed on the SPU film. The fully covered stents were assembled by wrapping a balloon-expandable stent with gelatin/heparin gel-layered SPU film and subsequently suturing and then gluing. To assess the validity of this covered stent in vivo, "half-covered" stents, in which half at the distal side was covered with the gel-layered SPU film, was implanted in rabbit common carotid arteries (about 3 mm in diameter). After 3 months of implantation, all the half-covered stents (n = 7) were patent. Regardless of the covered or noncovered region of the stents, the entire luminal surface of the stents was fully endothelialized and a thin neointimal tissue was formed. The potential advantages of a covered stent as designed above are discussed.     

新型临时血管转流装置在犬股动脉损伤再通的应用

目的本研究自行设计新型血管转流装置,并探讨其在犬股动脉损伤中的应用价值。方法取健康成年比格犬12只,体重(20±2)kg,通过手术制作股动脉损伤动物模型,使用新型血管临时转流装置联通离断的股动脉,按随机数表法分为A组、B组、C组,每组各4只。各组均于植入血管转流装置,术后每2 h进行静脉采血,行血常规、凝血常规检查;A组植入术后4 h处死,B组6 h处死,C组8 h处死,切取装置两侧股动脉进行组织学切片检查。结果血常规及凝血常规检查:白细胞计数(WBC)、血红蛋白(HGB)、血小板计数(PLT)、凝血酶原时间(PT)、凝血酶时间(TT)、部分活化凝血酶时间(APTT)、Fib(纤维蛋白原)各项指标术前、处死前比较差异无统计学意义(0.05);术前,植入术后4 h、6 h、8 h通过组织学检查未见动脉明显损伤。结论该新型血管临时血管转流装置自带固定球囊,可减少血管损伤,在短时间内可有效临时联通离断的股动脉,恢复下肢血液灌注。     

Interaction of antithrombin III with preadsorbed albumin-heparin conjugates

The adsorption of antithrombin III (AT III) onto polystyrene surfaces preadsorbed with albumin or albuminheparin conjugates was studied using a two step enzyme immuno assay. When AT III-buffer solutions were used, the highest adsorption values were measured on high affinity albumin-heparin conjugate pretreated surfaces. Less AT III adsorption was found on nonfractionated albumin-heparin conjugate preadsorbed surfaces. AT III adsorption could also be detected on low affinity conjugate and albumin coated surfaces. When AT III was adsorbed from plasma or plasma dilutions with buffer, only AT III on surfaces preadsorbed with high affinity or nonfractionated albumin-heparin conjugate was found. These results demonstrate that the heparin moiety of the conjugate is directed to the solution phase whereas the albumin moiety contacts the polystyrene surfaca     

Pretreatment of a Dacron graft with tissue factor pathway inhibitor decreases thrombogenicity and neointimal thickness: a preliminary animal study

The purpose of this study was to evaluate the effects of locally applied TFPI on the reduction of neointimal thickness in Dacron grafts. Seven millimeter internal diameter 5 cm lengths of albumin coated knitted Dacron grafts were interposed in the infrarenal aorta in 14 mongrel dogs. Before implantation, the grafts were immersed in saline solution containing 200 microg/ml of TFPI (TFPI group, n = 7) or 100 IU/ml of heparin (control group, n = 7) for 15 minutes at room temperature. Three months after implantation, neointimal thickness and percentage of graft stenosis were measured by computerized planimetry. All grafts were patent 3 months after implantation. Thrombus was found in one graft in the TFPI group, but observed in three of seven control grafts. Neointimal thickness in the TFPI group was significantly smaller than that in the control group (mean +/- SD, 0.26 +/- 0.1 mm vs. 0.57 +/- 0.15 mm, p < 0.001). Percentage of graft stenosis was significantly lower in the TFPI group than in the control group (13.4 +/- 5.3% vs. 26.9 +/- 7.0%, p < 0.001). Scanning electron micrographs showed that the neointima of TFPI treated grafts were completely covered by endothelial cells. The present results indicate that locally applied TFPI reduces thrombogenicity and neointimal thickness in albumin coated knitted Dacron grafts.     

Poly(DL-lactic acid) film surface modification with heparin for improving hemocompatibility of blood-contacting bioresorbable devices

This work describes a simple method to immobilize heparin by covalent bonding to the surface of poly(lactic acid) film with the aim of showing improved hemocompatibility. Carboxyl groups present in heparin molecules were activated by reaction with N-hydroxy-succinimide and allowed to react with free amino groups created at the surface of poly(DL-lactic acid) films by controlled aminolysis. Contact angle measurements and XPS analysis confirmed the binding. Quantification was determined by radioactivity using heparin labeled with tritium. The surface exhibited anti factor Xa activity, thus confirming the presence of bounded heparin that kept some biological activity. Finally platelets adhesion showed less platelet adhesion on heparin modified films as well as preserved morphology.     

The short-term effects on restenosis and thrombosis of echinomycin-eluting stents topcoated with a hydrophobic heparin-containing polymer

Although drug-eluting stents (DESs) have become the most effective means of treating coronary artery disease, safety concerns regarding their thrombogenicities remain to be surmounted. Here, we report on a novel type of DES capable of preventing restenosis and thrombosis. The DES was prepared by coating a bare metal stent with echinomycin (an anti-proliferative drug) in polyurethane by a spray drying method. Hydrophobic heparinized polymer was then topcoated onto stent over echinomycin/PU layer by dipping to improve hemocompatibility. The two-layered stent was characterized regarding surface and cross-sectional morphology, drug release pattern, platelet adhesion in vitro, and restenosis in vivo. It was found that the heparin topcoat acts as a diffusion barrier that allows the controlled release of drug in a sustained manner. Also, the heparin coated layer effectively reduced platelet adhesion, indicating excellent hemocompatibility. From the animal test using pigs, it was evident that the developed DESs can minimize neointimal proliferation and thrombus formation. The devised hydrophobic heparinized polymer-coated DES effectively reduced both restenosis and thrombosis, suggesting that they have potential as tools for the treatment of coronary artery diseases.     

Effect of biopassive and bioactive surface-coatings on the hemocompatibility of membrane oxygenators

Postoperative complications associated with cardiopulmonary bypass (CPB) surgery and extracorporeal circulation (ECC) procedures are still a major clinical issue. Improving the hemocompatibility of blood contacting devices used for ECC procedures may ameliorate various postpump syndromes. In a simulated CPB model using human blood, we investigated the hemocompatibility, fibrinogen adsorption, and platelet receptor (GPIIb-IIIa) binding capacity of surface-modified membrane oxygenators (Jostra Quadrox). Three groups were compared: (i) biopassive protein coatings (SafeLine), (ii) bioactive heparin coatings (BioLine), and (iii) noncoated controls. During the 2 h recirculation period, plasma concentrations of activation markers for platelets (beta-thromboglobulin), inflammation (elastase), complement (C5a), and coagulation (prothrombin fragment 1+2, thrombin-antithrombin III) were lower in the groups with biopassive and bioactive coatings compared to the noncoated group (p < 0.01). These parameters did not significantly differ between the two surface-coated groups, except for complement activation: C5a levels were higher in the biopassive group compared to the bioactive group (p < 0.01). Moreover, surface-coated oxygenators showed less fibrinogen adsorption, GPIIb-IIIa binding, and platelet/leukocyte adhesion (p < 0.01). We assume that fewer fibrinogen and platelet receptor molecules bound to the surface-coated oxygenator surfaces results in fewer platelet adhesion and activation, which will significantly contribute to the improved hemocompatibility of the biopassive and bioactive oxygenators. Our results suggest that the application of bioactive oxygenators (BioLine) during CPB surgery may reduce postoperative complications for the patient more effectively than biopassive oxygenators (SafeLine).