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

虽然许多人造血管移植物已经被实验或临床开发和评估，但作为小口径血管替代物应用时，没有一种能达到长期通畅。我们开发了一种小口径(直径3 mm)的血管移植物。采用甲基丙烯酸羟乙酯(HEMA)和苯乙烯(St)嵌段共聚涂料。在体外和体内实验中，HEMA-ST嵌段共聚物形成了微区结构，并表现出改善的血液相容性。接枝由三层结构组成：外层为涤纶，中层为聚氨酯，内层为HEMA-St嵌段共聚涂料。在犬双侧颈动脉置换术模型上对移植物进行评价。所有移植物均通畅，沿移植物长度包括吻合口均无可分离血栓。扫描电子显微镜显示移植管腔表面均匀的蛋白样层覆盖，无微血栓或细胞内衬，表面蛋白层厚度约为200A，无论植入时间长达一年，均可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分子吸收蛋白LayR在体内显示出非促胸腺活性，并确保了小口径血管移植物的长期通畅性，而不需要内皮细胞衬里。

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.