双层仿生抗凝血血管支架及体内血管再生的研究

In this project collagen and poly(L-lactide-co-ε-caprolactone)(P(LLA-CL)) will be electrospun into nanofiber and nanoyarn schaffolds in different blending ratios. The nanofiber and nanoyarn scaffolds will be test the mechanical properties and cell biocompatibility, so the scaffold with both the best mechanical properties and cell biocompatibility will be used for small diameter blood vessel scaffold fabrication. The in vitro biodegradability of the nanofiber and nanoyarn scaffolds will also be evaluated. Coaxial electrosping will be used to fabricate the core-shell nanofibers with heparin and CD34 antibody as core and collagen-P(LLA-CL) blend as shell, heparin supposed to give the nanofibers anticoagulation property, while, CD34 antibody suppose to let the nanofibers have the ability to capture the endothelial progenitor cell (EPCs) in the blood flowing. Both the anticoagulation property and the EPCs capture ability of the core-shell nanofibers will be evaluated in vitro and in vivo. Heparin and CD34 antibody release behavior from the core-shell nanofibers will be tested by UV-VIS spectroscopy and Elisa method. Futher more, an bi-layer biomimetic blood vessel scaffold with the core-shell nanofibers as inner layer and the circumferentially arranged nanoyarns as the out layer will be fabricated for in vivo blood vessel tissue regeneration. The bi-layer biomimetic blood vessel scaffold will be used to test the burst pressure and compliance to compare with the native blood vessel, the scaffold with similar mechanical properties as the native tissue will be implanted into the femoral artery of dog with 30mm in length, and the regenerated vessel at diferent implantation time will be used for patency test, endothelialization test and new tissue formation test. So that, the project has two biger parts, one is an ideal blood vessel scaffold fabrication and the other is to investigated the interaction between implanted blood veseel scaffold and around tissues in the body.

用胶原蛋白和P(LLA-CL)的复合纳米纤维和纳米纱制备小血管支架，集天然材料优良的生物相容性和合成材料优良的力学性能为一体。检测纳米纤维和纳米纱的力学性能、生物相容性和可降解性，并以这些性能为标准确定最佳胶原和P(LLA-CL)的复合比用作血管支架材料。同轴共纺含肝素和CD34抗体的皮芯结构的纳米纤维用作血管支架的内层，研究肝素和CD34抗体从纳米纤维中的缓释行为；研究此皮芯结构纳米纤维体外抗血小板粘附的能力和促进内皮祖细胞粘附和增殖的能力、植入狗的股动脉后抗血栓能力和内皮祖细胞俘获能力。制备内层为含肝素和CD34抗体的纳米纤维，外层为多孔绕轴平行排列的纳米纱的双层仿生血管支架，内层提供抗凝血和促内皮化环境，外层提供平滑肌细胞绕轴平行排列长入的环境。测定双层仿生支架的爆破强度和柔顺性，与天然血管的力学性能相比较。将双层仿生支架植入狗的30mm血管缺损，研究18个月内血管新组织的再生过程

采用同轴静电纺将肝素和CD133纺入胶原-PLCL 纳米纤维中作为血管支架的内层，采用动态水流静电纺制备胶原-PLCL纳米纱作为血管支架的外层，从而制备出内层抗凝血外层疏松多孔的双层血管支架。将此支架植入大鼠的腹主动脉2个月后再生出血管组织，内层形成了一层均匀的抗凝血内皮层，外层形成了平滑肌。.采用同轴静电纺将肝素和内皮生长因子纺入胶原-PLCL 纳米纤维中作为血管支架的内层，采用共轭静电纺制备出含平滑肌生长因子的胶原-PLCL纳米纱作为血管支架的外层，从而制备出内层抗凝血促内皮化外层疏松促平滑肌生长的双层血管支架。将此支架植入大鼠的腹主动脉2个月后再生出1cm的血管组织，内层形成了一层均匀的抗凝血内皮层，外层形成了平滑肌。.合成出可降解聚氨酯（C-PEEUU）新材料，将此材料肝素化和RGD接枝后静电纺成血管支架内层，然后C-PEEUU相分离得到多孔血管外层，从而制备出内层抗凝血外层疏松的聚氨酯血管支架，植入大白兔颈总动脉6个月后再生出1.2cm的血管组织，血流通常。.研究推出了三种血管组织工程支架，极大地推动了血管组织工程科学的发展，并且推出的血管组织工程支架极有产业化前景。