Department of Geriatrics, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.
Int J Nanomedicine. 2012;7:693-704. doi: 10.2147/IJN.S27849. Epub 2012 Feb 9.
Polyethylenimine (PEI), especially PEI 25 kDa, has been widely studied for delivery of nucleic acid drugs both in vitro and in vivo. However, it lacks degradable linkages and is too toxic for therapeutic applications. Hence, low-molecular-weight PEI has been explored as an alternative to PEI 25 kDa. To reduce cytotoxicity and increase transfection efficiency, we designed and synthesized a novel small-molecular-weight PEI derivative (PEI-Et, Mn: 1220, Mw: 2895) with ethylene biscarbamate linkages. PEI-Et carried the ability to condense plasmid DNA (pDNA) into nanoparticles. Gel retardation assay showed complete condensation of pDNA at w/w ratios that exceeded three. The particle size of polymer/pDNA complexes was between 130 nm and 180 nm and zeta potential was 5-10 mV, which were appropriate for cell endocytosis. The morphology of PEI-Et/pDNA complexes observed by atomic force microscopy (AFM) was spherically shaped with diameters of 110-190 nm. The transfection efficiency of polymer/pDNA complexes as determined with the luciferase activity assay as well as fluorescence-activated cell-sorting analysis (FACS) was higher than commercially available PEI 25 kDa and Lipofectamine 2000 in various cell lines. Also, the polymer exhibited significantly lower cytotoxicity compared to PEI 25 kDa at the same concentration in three cell lines. Therefore, our results indicated that the PEI-Et would be a promising candidate for safe and efficient gene delivery in gene therapy.
聚乙烯亚胺（PEI），尤其是 25kDa 的 PEI，已被广泛研究用于体外和体内核酸药物的递送。然而，它缺乏可降解键，对治疗应用来说毒性太大。因此，低分子量的 PEI 已被探索作为 25kDaPEI 的替代品。为了降低细胞毒性并提高转染效率，我们设计并合成了一种具有乙撑双氨基甲酸酯键的新型小分子聚乙烯亚胺衍生物（PEI-Et，Mn：1220，Mw：2895）。PEI-Et 具有将质粒 DNA（pDNA）凝聚成纳米颗粒的能力。凝胶阻滞实验表明，在 w/w 比超过 3 的情况下，pDNA 完全被凝聚。聚合物/pDNA 复合物的粒径在 130nm 至 180nm 之间，zeta 电位为 5-10mV，适合细胞内吞。原子力显微镜（AFM）观察到的 PEI-Et/pDNA 复合物的形态呈球形，直径为 110-190nm。通过荧光素酶活性测定和荧光激活细胞分选分析（FACS）确定的聚合物/pDNA 复合物的转染效率在各种细胞系中均高于市售的 25kDaPEI 和 Lipofectamine 2000。此外，与相同浓度的 25kDaPEI 相比，该聚合物在三种细胞系中表现出显著降低的细胞毒性。因此，我们的结果表明，PEI-Et 将是基因治疗中安全有效的基因递送的有前途的候选物。
