Development of small caliber vascular graft with stabulizing blood-material interface with monolayr absorbed protein layr.

虽然在实验和临床中已经开发和评价了许多人工血管移植物，但作为小直径血管替代物应用时，没有一种能达到长期通畅。我们使用2-羟乙基甲基丙烯酸酯（HEMA）和乙烯（St）嵌段共聚物涂层开发了一种小口径血管移植物（3毫米）。HEMA-St嵌段共聚物形成微畴结构，体外和体内实验均显示出改善的血液相容性。接枝剂由三层结构组成：外层为涤纶，中间层为聚氨酯，内层为HEMA-St嵌段共聚物涂层。在犬双侧颈动脉置换术模型中对移植物进行评价。所有的移植物都是通畅的，没有可拆卸的血栓沿着移植物的长度，包括吻合处。移植管腔的扫描电镜显示相当干净的表面覆盖着均匀的蛋白样层，没有微血栓或内皮细胞衬里。透射电镜测得的表面蛋白层厚度约为200A，无论植入期长达一年，都可以描述为单层蛋白吸收。在HEMA-St嵌段共聚物表面形成的稳定的单层吸收蛋白层在体内表现出非成胸活性，并在没有内皮细胞衬里的情况下确保小直径血管移植物的长期通畅。

Although many synthetic vascular grafts have been developed and evaluated experimentally or clinically, none of them have met long-term patency when applied as small diameter vascular substitution. We have developed a small caliber vascular graft (3 mm id.) using 2-hydroxyethylmetacrylate (HEMA) and Stirene (St) block copolymer coating. HEMA-St block copolymer formed micro-domain structure and demonstrated improved blood compatibility in both in vitro and in vivo experiments. The graft consists of three layred structure : Dacron for the outer layr, polyurethane in middle layr, and a HEMA-St block copolymer coating for the inner layr. The grafts were evaluated in dogs bilateral carotid replacement model. All grafts were patent without detachable thrombi along the graft length including anastomotic sites. Scanning electron micrographs of retrieved graft lumen showed fairly clean surfaces covered with a homogeneous protein-like layr without microthrombi or endotherial ell lining.The thickness of the surface protein layr measured by a transmission electron microscopy was about 200A which can be described as monolayr protein absorption regardless of implantation period of as much as one year. A stable monolayr absorbed protein layr formed on HEMA-St block copolymer surfaces demonstrated nonthorombogenic activities in vivo and secure long-term patency of small caliber vascular grafts with the absence of an endotherial cell lining.