共价交联水蛭素/海藻酸钠涂层抗凝血修饰膨体聚四氟乙烯人工血管(英文)

Hemocompatible coating of expanded polytetrafluoroethylene vascular graft based on cross-linked alginate/recombinant hirudin multilayer

背景:对于直径小于6mm的血管,血栓形成或内膜增生等原因限制了小口径膨体聚四氟乙烯人工血管的使用。目的:实验拟用共价交联的海藻酸钠和水蛭素层层自组装后对小口径膨体聚四氟乙烯人工血管进行表面修饰和改性,观察其血液相容性。设计:观察性实验。单位:实验于2006-03/2007-06在哈尔滨工业大学生物医学工程中心纳米医药与生物传感器实验室完成。材料:膨体聚四氟乙烯人工血管(W.LGore&Associates,Inc.,Flagstaff,AZ,直径4mm);海藻酸钠购于美国Sigma公司;水蛭素购于Calbiochem公司。方法:首先用全氟磺酸修饰膨体聚四氟乙烯表面,通过静电吸引层层自组装吸附多层海藻酸钠/重氮树脂/水蛭素提供锚定位点,应用BCA法推算吸附在人工血管表面的水蛭素质量。主要观察指标:①材料表面吸附蛋白浓度。②接触角。③衰减全反射-傅立叶变换红外光谱。④扫描电镜表征材料表面形貌及血小板黏附情况。⑤活化部分凝血激酶时间、凝血酶原时间。⑥溶血度。结果:①修饰后的人工血管表面吸附的水蛭素浓度为16.35μg/cm2。②衰减全反射-傅立叶变换红外光谱结果显示出特征峰位,证明水蛭素成功固定到人工血管表面。③修饰后人工血管的接触角降低,亲水性能增强。④修饰后的人工血管与未修饰的人工血管相比,活化部分凝血激酶时间和凝血酶原时间延长、血小板黏附情况减少,具有更好的血液相容性。结论:共价交联水蛭素/海藻酸钠涂层抗凝血修饰可提高膨体聚四氟乙烯人工血管的表面性能及血液相容性。

BACKGROUND： Thrombus formation and neointimal hyperplasia limit its use for revascularization of small-caliber vessels （〈 6 mm diameter） in the coronary or peripheral circulation. OBJECTIVE： To improve hemocompatibility, the luminal surface of a small diameter expanded polytetrafluoroethylene （ePTFE） vascular prosthesis was modified with alginate and recombinant hirudin. DESIGN： Observational experiment. SETTING： This study was performed in Nanomedicine and Biosensor Laboratory, Bio-X Center, Harbin Institute of Technology from Marcy 2006 to June 2007. MATERIALS： The GORE-TEX ePTFE vascular grafts （W.L Gore ＆ Associates, lnc., Flagstaff, AZ） used in this study were 4 mm in internal diameter, rHir was obtained from Calbiochem, Germany. Sodium alginate （also called alginic acid sodium salt; medium viscosity） was purchased from Sigma. METHODS： A p-diazonium diphenyl amine polymer （PA） was used as an interlayer between alginate and recombinant hirudin （rHir）. The diazonium moieties were capable of covalently coupling with electron-rich aromatic systems such as histidine and tyrosine residues of hirudin. No need for chemical pretreatment took an advantage by preserving the bulk properties with almost no effect on stability and elasticity of the ePTFE vascular graft, rHir amount on ePTFE surface was determined by the Micro BCA （Bicinchoninic acid） Protein Assay kit. MAIN OUTCOME MEASURES： ① Determination rHir amount on ePTFE surface; ② Static water contact angles; ③ Attenuated total reflectance fourier transform infrared spectroscopy （ATR-FTIR） was employed to confirm the change taking place in the ePTFE graft surface modification process; ④ Characterization of the surface morphology and platelet adhesion by SEM; ⑤ APTT and PT; ⑥ Percent hemolysis. RESULTS： ① The amount of rHir adsorbed onto the ePTFE vascular was deduced to be 16.35 μg/cm^2. ② Surface analysis ATR-FTIR revealed the presence of new functional groups on the modified graft surfaces. ③ The water contact angle of the modified graft surface decreased. ④ The longer APTT and PT value lower than 5% hemolysis level and dramatically decrease of platelet adhesion assay showed that rHir modified graft had great improved blood compatibility. CONCLUSION： Cross-linked Alg/rHir onto ePTFE can improve luminal surface and hemocompatibility.