Hashem Nia Azadeh, Behnam Behzad, Taghavi Sahar, Oroojalian Fatemeh, Eshghi Hossein, Shier Wayne T, Abnous Khalil, Ramezani Mohammad
Pharmaceutical Research Center , School of Pharmacy , Mashhad University of Medical Sciences , Mashhad , Iran . Email:
Department of Chemistry , Faculty of Sciences , Ferdowsi University of Mashhad , Mashhad , Iran.
Medchemcomm. 2016 Nov 30;8(2):364-375. doi: 10.1039/c6md00481d. eCollection 2017 Feb 1.
Polyethylenimine (PEI) is a widely used non-viral vector for DNA delivery. One major obstacle of higher molecular weight PEIs is the increased cytotoxicity despite the improved transfection efficiency and numerous chemical modifications that have been reported to overcome this problem. Carbon nanotubes (CNT) are carbon nanomaterials capable of penetrating into cell membranes with no cytotoxic effects. Covalent and noncovalent functionalization methods have been used to improve their solubility in aqueous media. The idea of conjugating PEIs and CNT through different chemical bonds and linkers seems promising as it may result in highly effective carriers due to combination of the transfection ability of PEI with cell internalization of CNT. In this study, six different water-soluble PEI conjugates of single-walled carbon nanotubes (SWNTs) were prepared by grafting PEI with one of three molecular weights (1.8, 10 and 25 kDa) through succinate as a linker which refers to "an organic moiety through which a SWNT is conjugated to PEI." The succinate linker was introduced to the surface of SWNTs through two different chemical strategies: a) ester and b) acyl linkages. The resulting SWNT-PEI vectors were characterized by IR spectroscopy, thermogravimetric analysis (TGA) and SEM imaging. All synthesized carriers were evaluated and compared for their cytotoxicity and transfection efficiency in murine neuroblastoma cells as polyplexes with plasmid DNA for luciferase and green fluorescent protein (GFP). The most efficient carriers were prepared by attaching PEI with the lowest molecular weight (1.8 kDa) through acyl linkage, which gave a transfection efficiency 190-fold greater than that of the corresponding free PEI. Transfection efficiency was the highest in polyplexes prepared with acyl-linked conjugates in all the plasmid/vector ratios studied.
聚乙烯亚胺（PEI）是一种广泛应用于DNA递送的非病毒载体。尽管高分子量PEI的转染效率有所提高，且有许多化学修饰方法被报道可克服该问题，但细胞毒性增加仍是其主要障碍之一。碳纳米管（CNT）是一种能够穿透细胞膜且无细胞毒性作用的碳纳米材料。共价和非共价功能化方法已被用于提高其在水性介质中的溶解度。通过不同化学键和连接体将PEI与CNT偶联的想法似乎很有前景，因为PEI的转染能力与CNT的细胞内化作用相结合可能会产生高效载体。在本研究中，通过琥珀酸作为连接体（指“单壁碳纳米管（SWNTs）与PEI偶联的有机部分”），将三种分子量（1.8、10和25 kDa）之一的PEI接枝到SWNTs上，制备了六种不同的水溶性PEI - SWNTs偶联物。琥珀酸连接体通过两种不同的化学策略引入到SWNTs表面：a）酯键和b）酰基键。通过红外光谱、热重分析（TGA）和扫描电子显微镜成像对所得的SWNT - PEI载体进行了表征。所有合成的载体作为与用于荧光素酶和绿色荧光蛋白（GFP）的质粒DNA形成的多聚体，在小鼠神经母细胞瘤细胞中评估并比较了它们的细胞毒性和转染效率。最有效的载体是通过酰基键连接最低分子量（1.8 kDa）的PEI制备的，其转染效率比相应的游离PEI高190倍。在所研究的所有质粒/载体比例下，用酰基连接的偶联物制备的多聚体的转染效率最高。
