介孔技术构建多功能生物活性人工血管研究

Owing to the lack of antithrombogenicity and a function endothelial cell of small-diameter(<6 mm) vascular prosthesis, causing clinical failure, plentiful studies have been carried out to improve the biocompatibility of vascular grafts, but a clinical acceptable small diameter artificial grafts have yet been not developed. The most popular method for improving biocompatibility is the surface modification of biomaterials for early thromboresistant surface and Self-endothelialization in the follow-up. The aim of the present study was first to demonstrate the possibility of building up such a bioactive molecule-loaded mesoporous ePTFE grafts, which was based on mesoporous channel and its application, for improving slow-release ability. The release performance of heparin and e vascular endothelial growth factor(VEGF) can be feasibly controlled by tuning the mesostructure of vessel and mesoporous channel modification. The heparin-loaded and VEGF-loaded mesoporous-based vascular prosthesis was synthesized. The rates and activity of heparin and VEGF released from samples samples and The implantation assay of experimental animal in vivo were determined to verify superior antithrombogenicity and Self-endothelialisation of modified prosthesis,and building tissue engineering of vascular graft. This progress may open an avenue for the design and synthesis of new functional biomaterials, which is important implications for improving development of interdiscipline and reducing medical expense.

由于植入血管材料缺乏抗血栓性和内皮层的形成，导致了小口径的人工血管临床应用的失败。本项目计划通过将介孔技术引入到人工血管中，利用介孔孔道的纳米限域效应和介孔孔道的修饰，实现生物活性分子在移植材料上的固载和不同的缓释能力。调变介孔材料的孔道结构及形貌，合成对肝素和内皮细胞生长因子（VEGF）具有优良吸附缓释能力的介孔材料；制备含介孔结构的人工血管，并固载肝素与VEGF于介孔孔道中，达到既有肝素的抗血栓抗过度增殖能力，又保持VEGF的人工血管形成内皮能力，实现人工血管长期通畅性。通过该课题的研究，我们将开拓介孔材料在生命科学领域的新应用，可望获得具有远期通畅的多功能的生物活性小口径人工血管，对于促进交叉学科发展、降低患者的医疗费用具有重要的意义。

目的 构建负载肝素和内皮细胞生长因子(VEGF)的具有多功能活性的介孔膨体聚四氟乙烯(ePTFE)人工血管。 方法　制备不同性能的固载肝素和VEGF的介孔人工血管，标记为CMBVP-n(n=1,2,3)。检测肝素和VEGF的释放性能。通过体内种植实验，内皮祖细胞(EPCs)增殖实验，细胞粘附率测定和荧光显微镜观察修饰血管的生物相容性。结果　成功制备出固载肝素和VEGF的介孔人工血管。缓释性能显示具有较大孔径的CMBVP-3 在7天后肝素累积缓释量达到210±18.5g/cm2，VEGF累积缓释量达到1356±110.7 pg/cm2，比起合成的其他材料(CMBVP-1,2材料肝素累积缓释量分别为195±22.2g/cm2, 183±21.1g/cm2；CMBVP-1,2的VEGF累积缓释量分别为798.5±105.5 pg/cm2, 1024±95.6 pg/cm2）具有更优越的缓释性能(P<0.05)；皮下种植实验显示修饰材料无生物毒性；细胞增殖实验显示EPCs在CMBVP-3材料膜上生长5天后OD值为1.54±0.12，比起其他组（ePTFE材料、介孔ePTFE、含肝素介孔ePTFE组OD值分别为0.79±0.09，0.91±0.15和1.1±0.21）明显促进了EPCs生长和增殖 (P<0.05)；细胞粘附实验显示CMBVP-3 细胞种植1天后粘附率达(89.9±6.47)%，比起其他组（ePTFE材料，介孔ePTFE，含肝素介孔ePTFE组OD值分别为(59.6±4.15)%, (61.9±6.52)%和(66.3±6.19)%）明显增加了细胞的粘附性 (P<0.05)。荧光显微镜下观察EPCs能够在CMBVP血管表面有更好的生长粘附和分化增殖。结论　固载肝素和VEGF的介孔ePTFE血管具有优越的缓释性能，保持了人工血管快速内皮化的能力，具有良好的生物相容性。