Park K D, Okano T, Nojiri C, Kim S W
Department of Pharmaceutics, University of Utah, Salt Lake City 84112.
J Biomed Mater Res. 1988 Nov;22(11):977-92. doi: 10.1002/jbm.820221103.
Heparin was immobilized onto segmented polyurethane-urea surfaces (Biomer) using hydrophilic poly(ethylene oxide) spacers of different chain lengths. The use of the hydrophilic spacer, poly(ethylene oxide), reduces protein adsorption and subsequent platelet adhesion on the surface. In addition, the bioactivity of the immobilized heparin is enhanced by the incorporation of these spacers. Immobilized heparin bioactivity is shown to be a function of PEO spacer length. Use of hydrophilic PEO spacers demonstrates that immobilized heparin's bioactivity is consistently higher than that of the C6 alkyl spacer, but heparin-immobilized surfaces demonstrate no chain length effect on platelet adhesion, even though they show less platelet adhesion compared to Biomer controls. In the case of PEO-grafted surfaces, platelet adhesion is decreased compared to Biomer controls, and C6 alkyl spacer-grafted surfaces, and exhibits a minimum at PEO 1000. In ex vivo A-A shunt experiments under low flow and low shear conditions, all heparinized surfaces exhibit significant prolongation of occlusion times compared to Biomer controls, indicating an ability of immobilized heparin to inhibit thrombosis in whole blood.
使用不同链长的亲水性聚环氧乙烷间隔物将肝素固定在嵌段聚氨酯-脲表面（Biomer）上。亲水性间隔物聚环氧乙烷的使用减少了蛋白质吸附以及随后血小板在表面的黏附。此外，通过并入这些间隔物，固定化肝素的生物活性得以增强。固定化肝素的生物活性显示为聚环氧乙烷间隔物长度的函数。使用亲水性聚环氧乙烷间隔物表明，固定化肝素的生物活性始终高于C6烷基间隔物，但固定有肝素的表面对血小板黏附没有链长效应，尽管与Biomer对照相比它们显示出较少的血小板黏附。在聚环氧乙烷接枝表面的情况下，与Biomer对照以及C6烷基间隔物接枝表面相比，血小板黏附减少，并且在聚环氧乙烷1000时表现出最小值。在低流量和低剪切条件下的体外动-静脉分流实验中，与Biomer对照相比，所有肝素化表面均显示出闭塞时间的显著延长，表明固定化肝素具有抑制全血中血栓形成的能力。
