Leung Jennifer M, Berry Leslie R, Chan Anthony K C, Brash John L
a School of Biomedical Engineering , Hamilton , Ontario , Canada.
J Biomater Sci Polym Ed. 2014;25(8):786-801. doi: 10.1080/09205063.2014.907669. Epub 2014 Apr 15.
To prevent coagulation in contact with blood, polydimethylsiloxane (PDMS) was modified with an antithrombin-heparin (ATH) covalent complex using polyethylene glycol (PEG) as a linker/spacer. Using NHS chemistry, ATH was attached covalently to the distal chain end of the immobilized PEG linker. Surfaces were characterized by contact angle and X-ray photoelectron spectroscopy; attachment was confirmed by decrease in contact angles and an increase in nitrogen content as determined by X-ray photoelectron spectroscopy. Protein interactions in plasma were investigated using radiolabeled proteins added to plasma as tracers, and by immunoblotting of eluted proteins. Modification of PDMS with PEG alone was effective in reducing non-specific protein adsorption; attachment of ATH at the distal end of the PEG chains did not significantly affect protein resistance. It was shown that surfaces modified with ATH bound antithrombin selectively from plasma through the pentasaccharide sequence on the heparin moiety of ATH, indicating the ability of the ATH-modified surfaces to inhibit coagulation. Using thromboelastography, the effect of ATH modification on plasma coagulation was evaluated directly. It was found that initiation of coagulation was delayed and the time to clot was prolonged on PDMS modified with ATH/PEG compared to controls. For comparison, surfaces modified in a similar way with heparin were prepared and investigated using the same methods. The data suggest that the ATH-modified surfaces have superior anticoagulant properties compared to those modified with heparin.
为防止与血液接触时发生凝血，使用聚乙二醇（PEG）作为连接体/间隔物，用抗凝血酶 - 肝素（ATH）共价复合物对聚二甲基硅氧烷（PDMS）进行修饰。利用NHS化学方法，将ATH共价连接到固定化PEG连接体的远端链端。通过接触角和X射线光电子能谱对表面进行表征；通过接触角减小以及X射线光电子能谱测定的氮含量增加来确认连接。使用添加到血浆中的放射性标记蛋白质作为示踪剂，并通过对洗脱蛋白质进行免疫印迹来研究血浆中的蛋白质相互作用。仅用PEG对PDMS进行修饰可有效减少非特异性蛋白质吸附；在PEG链的远端连接ATH对蛋白质抗性没有显著影响。结果表明，用ATH修饰的表面通过ATH肝素部分上的五糖序列从血浆中选择性地结合抗凝血酶，这表明ATH修饰的表面具有抑制凝血的能力。使用血栓弹性描记法直接评估ATH修饰对血浆凝血的影响。结果发现，与对照相比，用ATH/PEG修饰的PDMS上凝血的起始延迟且凝血时间延长。为作比较，制备了以类似方式用肝素修饰的表面，并使用相同方法进行研究。数据表明，与用肝素修饰的表面相比，ATH修饰的表面具有更好的抗凝血性能。
