肝素共价接枝聚氨酯表面的研究.pdfVIP

摘 要 本文主要研究了肝素改性聚氨酯(PU)材料的方法及改性后聚氨酯材料的血 液相容性。肝素改性聚氨酯膜表面，既要保证高接枝密度，也要保证生物构象不 被破坏，才能使改性后的聚氨酯材料有较好的血液相容性。实验采用了三种方法 将肝素接枝到聚氨酯膜表面。第一种方法，六亚甲基二异氰酸酯（HDI ）的一端 先与聚氨酯膜表面反应，另一端直接活化为氨基，然后利用肝素上的羧基和膜表 面的氨基的共价反应，将肝素接枝到聚氨酯膜表面。甲苯胺蓝检测发现，所接枝 的肝素密度较低，无法达到理想的抗凝血效果。 第二种方法是先用 HDI 活化聚氨酯材料膜表面，然后将聚乙烯亚胺（PEI ） 接枝到膜表面。所形成的 PU-PEI 膜上的多氨基再与肝素上的羧基发生共价反应。 肝素的接枝量有一定程度的提高。但是由于溶剂对聚氨酯有较大的溶解性，聚氨 酯膜表面形态被破坏，影响到材料的抗凝血效果。 第三种方法利用接枝肝素和磷酰胆碱来提高聚氨酯材料的血液相容性。采用 本体聚合的方法利用 PEI 放大 PU 膜表面的接枝位点，然后利用膜表面的氨基与 肝素的羧基、醛基磷酰胆碱的醛基发生共价反应。改性前后膜表面的氨基浓度采 用茚三酮的方法进行检测。接枝到PU-PEI 膜表面的肝素浓度由甲苯胺蓝方法来 测定。同时，分别用水吸收率、水接触角、傅里叶变换红外光谱（FT-IR ）、X 射线光电子能谱（XPS ）、扫描电子显微镜（SEM）、原子力显微镜（AFM ）等 测试手段对改性前后的膜进行了表征。结果表明改性后聚氨酯膜表面的亲水性和 血液相容性都有明显增强。 关键词： 聚氨酯，肝素，磷酰胆碱，聚乙烯亚胺，血液相容性 ABSTRACT In this paper, surface modification of polyurethane (PU) was studied to improve its hydrophilicity and hemocompatibility via three methods. The grafting density and structural of heparin decided whether polyurethane had good blood compatibility. Firstly, isocyanate functional groups were introduced onto PU surface by treatment of hexamethylene diisocyanate. Heparin was covalently coupled with PU-NH2 surface. The grafting density of heparin (HEP) was not high enough to achieve the goal of anticoagulant. Secondly, isocyanate functional groups were introduced onto PU surface. Polyethylenimine(PEI) was linked onto the PU surface to obtain the PEI conjuncted PU surface (PU-PEI). Heparin was covalently coupled with PU-PEI surface. The grafting density of heparin was improved. However, the solubility of PU surface morphology was destroyed by the solvent. HEP and phosphorylcholine groups (PC) were grafted onto PU surface in order to improve biocompatibility and anticoagulant activity. After the surface grafting sites of PU wer