双磷酸改性血管支架作为基因载体的研究

目的 将基因通过化学偶联和特异性免疫结合在双磷酸氨基酯改性的316L不锈钢冠状动脉支架上,评价支架改性和负载质粒DNA的效果.方法 金属支架首先利用双磷酸氨基酯改性引入氨基活性基团,化学偶联抗DNA抗体,然后免疫偶联质粒DNA,得到血管支架上负载抗体和基因的模型.结果 利用X射线光电子能谱(XPS)和原子力显微镜(AFM)等分析确定了支架表面磷酸氨基的存在,同位素标记验证了改性后支架表面结合的抗体具有很好的稳定性和结合容量.结论 双磷酸氨基改性的血管支架表层富含可反应氨基,可以作为新型反应界面,与生物活性分子进行偶联反应.

Study on gene delivery system based on bisphosphonate-mediated gene-eluting stent

Objective The aim of the present study was to investigate the incorporation of plasmid DNA （pDNA） onto a coronary stent by chemo-immuno-conjugation for achieving site-specific gene delivery. Methods A gene eluting stent was fabricated by reacting with polyallylamine bisphosphonate （PAA-BP） to introduce amine reactive groups on the surface. Then an anti-DNA antibody was chemically coupled and pDNA was immunologically tethered on the stent surface. Radioactive-labeled antibody was used to evaluate binding capacity and stability. Results The presence of amine groups on the modified stent surface was confirmed by XPS and AFM analysis. The isotope label assay indicated that the amount of antibody chemically linked on the stents was 15-fold higher than that of the control stent and its retention time was also significantly longer. Conclusion The results suggested that a large amount of reactive amine groups were introduced on the PAA-BP modified 316L coronary stent surface. This study provide a potential metal surface modification method that could facilitate coupling and tethering of biological molecules such as anti-DNA antibody and plasmid DNA （pDNA） to achieve sustained and highly localized gene delivery for substrate-mediated gene transfection.