Lin J C, Tseng S M
Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan 70101.
J Mater Sci Mater Med. 2001 Sep;12(9):827-32. doi: 10.1023/a:1017937304964.
Hirudin, a protein composed of 65 or 66 amino acid, is a newly risen anticoagulant agent and has been considered as the most potent thrombin inhibitor. Hirudin can block the active site of thrombin by means of its carboxylic acid reaction with the active regime of thrombin, and becomes a tightly bound complex, and thus controls the formation of thrombus. Hirudin was covalently immobilized onto the water-soluble carbodiimide preactivated and chromic acid oxidized PE surface. Surface chemistry analysis indicated that a certain amount of carboxylic acid groups was generated on the polyethylene surface after oxidation with chromic acid solution. The amount of carboxylic acid functional group increased with the oxidation time. In addition, polyethylene surface was etched by chromic acid solution, and a rougher surface was created. The morphology of oxidized polyethylene surface was similar to each other among the samples with oxidation time from 1 to 8 min. ESCA results indicated the number of hirudin molecules immobilized was constant at the reaction time studied. In vitro platelet adhesion assay indicated the number of adhered platelets on the oxidized polyethylene surface increased significantly after oxidation. In contrast, surface with hirudin immobilization showed a reduction in adhered platelet density than the chromic acid oxidized counterpart due to the decrease of platelet-activating capability by the hirudin-thrombin complex and the differences in the adsorbed protein composition.
水蛭素是一种由65或66个氨基酸组成的蛋白质，是一种新出现的抗凝剂，被认为是最有效的凝血酶抑制剂。水蛭素可通过其羧酸与凝血酶活性区域的反应来阻断凝血酶的活性位点，形成紧密结合的复合物，从而控制血栓的形成。水蛭素被共价固定在经水溶性碳二亚胺预活化和铬酸氧化的PE表面。表面化学分析表明，用铬酸溶液氧化后，聚乙烯表面产生了一定量的羧酸基团。羧酸官能团的数量随氧化时间增加。此外，铬酸溶液对聚乙烯表面有蚀刻作用，形成了更粗糙的表面。在氧化时间为1至8分钟的样品中，氧化聚乙烯表面的形态彼此相似。ESCA结果表明，在所研究的反应时间内，固定化的水蛭素分子数量是恒定的。体外血小板黏附试验表明，氧化后聚乙烯表面黏附的血小板数量显著增加。相比之下，固定有水蛭素的表面与铬酸氧化的表面相比，黏附的血小板密度降低，这是由于水蛭素 - 凝血酶复合物降低了血小板活化能力以及吸附的蛋白质组成不同所致。
