论文部分内容阅读
本文设计和合成了具有血管内皮细胞靶向性的环五肽RGD(cyclo-[Arg-Gly-Asp-D-Tyr-Lys],Tyr-RGD)修饰的纳米基因载体聚乙二醇-聚乙烯亚胺(PEG-PEI),并研究其纳米特性、载药特性及其体内外的肿瘤靶向特性。采用化学方法合成所需要的纳米载体,鉴定该纳米载体的纳米特性及载药特性,并采用体外血管内皮细胞竞争结合实验研究其靶向性,最后将荧光标记的纳米载体注入荷瘤小鼠体内,观察其肿瘤靶向性。Tyr-RGD-PEG-PEI纳米载体采用分步合成方法,所获得的载体粒径约为145nm,其对小分子干扰核糖核酸(siRNA)的包封率好,血浆内孵育30min,仅约3%的siRNA游离出来,结构稳定。薄层层析法分析鉴定其为单一斑点(Rf0.65)。受体竞争实验表明该纳米载体可有效地与多肽精氨酸-甘氨酸-天冬氨酸(RGD)竞争结合内皮细胞膜上的受体;荷瘤小鼠实验表明,载有荧光标记siRNA的Tyr-RGD-PEG-PEI纳米药物注射入小鼠体内24h后,主要分布在肿瘤组织内,而无Tyr-RGD靶向的纳米药物则除了瘤体内,还分布在肝脏、肺等脏器。合成的Tyr-RGD靶向纳米载体Tyr-RGD-PEG-PEI具有较好的纳米特性和高效的基因药物包封率,荷瘤裸鼠研究表明其肿瘤的靶向性明显优于无Tyr-RGD靶向的纳米药物。
In this paper, we designed and synthesized polyethylene glycol-polyethylene (PEG) -modified nanocarrier with cyclic pentapeptide RGD (cyclo- [Arg-Gly-Asp-D-Tyr-Lys] Imine (PEG-PEI), and study its nano-characteristics, drug-loading properties and in vitro and in vivo tumor targeting properties. The nanocarriers needed for the synthesis of the nanocarriers were identified by chemical methods. The nanocarriers were characterized by their nanometer properties and drug-loading properties. The targeting properties of the nanocarriers were determined by competitive binding assay with vascular endothelial cells in vitro. Finally, the fluorescent-labeled nanocarriers were injected into tumor-bearing mice , Observe its tumor targeting. Particle size of Tyr-RGD-PEG-PEI nanocarrier was about 145nm. The encapsulation efficiency of Tyr-RGD-PEG-PEI nanocarrier was small, The siRNAs are free and stable. Thin layer chromatography analysis identified it as a single spot (Rf 0.65). Receptor competition experiments show that the nanocarrier can effectively compete with the polypeptide arginine-glycine-aspartic acid (RGD) to bind receptors on the endothelial cell membrane; experiments in tumor-bearing mice show that the fluorescently labeled siRNA containing Tyr- RGD-PEG-PEI nanomedicine was injected into the mice in vivo for 24 hours and mainly distributed in the tumor tissues. However, the non-targeted RGD-PEG-PEI nanomedicine was distributed in the liver and lungs besides the tumor. The synthesized Tyr-RGD targeted nanocarrier Tyr-RGD-PEG-PEI has better nanometer characteristics and efficient encapsulation efficiency of gene drugs. The study of tumor-bearing nude mice shows that the targeting of Tyr-RGD-PEG-PEI is significantly better than that without Tyr-RGD Targeted nanomedicine.