共修饰冰片和叶酸的阿霉素聚酰胺-胺纳米给药系统的制备及体外评价

Preparation and in vitro evaluation of borneol and folic acid co-modified doxorubicin loaded PAMAM drug delivery system

本文基于聚酰胺-胺[poly(amido amine),PAMAM G5]树状大分子,通过化学合成叶酸(folic acid,FA)介导的、冰片(borneol,BO)修饰的新型纳米载体(FA-BO-PAMAM),并包载抗癌药物阿霉素(doxorubicin,DOX),以达到增加药物血脑屏障(blood-brain barrier,BBB)的透过性和提高脑胶质瘤靶向性的目的。通过1H NMR验证合成载体的结构,采用透射电镜(TEM)和纳米粒度-电位分析仪(DLS)分别对FA-BO-PAMAM的形貌、粒径和表面电势进行表征;另外基于脑血管内皮细胞(HBMEC)和脑胶质瘤细胞(C6)双细胞模型考察载体的细胞毒性,以及载药复合物体外跨BBB膜转运的能力、细胞摄取效率和体外抗肿瘤的效果。1H NMR的结果表明FA-BO-PAMAM合成成功,在TEM下呈类圆形,大小分布均匀,粒径为(22.28±0.42)nm,zeta电位为(7.6±0.89)m V(n=3)。细胞毒性和体外跨BBB转运实验结果显示,PAMAM功能化修饰冰片显著地降低了PAMAM毒性,提高了生物安全性,同时增加了载药复合物跨BBB转运率。细胞摄取和体外抗肿瘤实验结果表明,叶酸的修饰增加了C6细胞对载药复合物的总摄取量,且提高了体外对C6细胞的抑制率。因此,该新型靶向纳米载体增加了药物在肿瘤部位的蓄积量,显示了其在治疗脑胶质瘤应用中的潜能。

A novel targeting drug carrier（FA-BO-PAMAM） based on the PAMAM G5 dendrimer modified with borneol（BO） and folic acid（FA） molecules on the periphery and doxorubicin（DOX） loaded in the interior was designed and prepared to achieve the purposes of enhancing the blood-brain barrier（BBB） transportation and improving the drug accumulation in the glioma cells. 1H NMR was used to confirm the synthesis of FA- BO-PAMAM; its morphology and mean size were analyzed by dynamic light scattering（DLS） and transmission electron microscope（TEM）. Based on the HBMEC and C6 cells, cytotoxicity assay, transport across the BBB, cellular uptake and anti-tumor activity in vitro were investigated to evaluate the properties of nanocarriers in vitro. The results showed that the nanocarrier of FA-BO-PAMAM was successfully synthesized, which was spherical in morphology with the average size of（22.28 ± 0.42） nm, and zeta potential of（7.6 ± 0.89） m V. Cytotoxicity and transport across the BBB assay showed that BO-modified conjugates decreased the cytotoxicity of PAMAM against both HBMEC and C6 cells and exhibited higher BBB transportation ability than BO-unmodified conjugates; moreover, modification with FA increased the total uptake of DOX by C6 cells and enhanced the cytotoxicity of DOX-polymer against C6 cells. Therefore, FA-BO-PAMAM is a promising nanodrug delivery system in employing PAMAM as a drug carrier and treatment for brain glioma.