中文摘要：

Polyethylenimine (PEI ) 带着最高的猫作为一个有效基因搬运人被知道了离子的费用潜力。与它的 cytotoxicity 一起， PEI 的高 transfection 效率强烈取决于它的分子的重量。提高它的基因交货效率并且最小化 cytotoxicity，我们综合了有可被细菌破坏的连接的小 cross-linked PEI 并且在 vitro 评估了他们的 transfection 效率。在这研究，分叉有 800 Da 的分子的重量的 PEI 是由小 diacrylate 的 cross-linked [1,4-butanediol diacrylate 或乙烯乙二醇 dimethacrylate (EGDMA )] 为 2-6 h。cross-linked PEI 在的效率在包含提高的绿色的原生质标志 DNA 的 vitro transfection，荧光灯的蛋白质(EGFP ) 记者基因在黑瘤 B16F10 被估计房间线和其它房间线。流动 cytometry 被用来确定原生质标志和 transgene 表示水平的细胞的入口效率。在这些房间的 cross-linked PEI 的 cytotoxicities 被 MTT 试金评估。 EGDMA-PEI 800-4h ，典型 cross-linked PEI 这里报导了，调停记者基因的更有效的表情比商业地可得到的 25-kDa 分叉 PEI 控制，并且导致了 B16F10 房间的基因交货的9褶层增加和 293T 房间的16褶层增加，当没有 cytotoxicity 为基因交货以优化条件被发现时。而且，息肉法律的 transfection 活动面对浆液蛋白质被保存。

英文摘要：

Polyethylenimine （PEI） has been known as an efficient gene carrier with the highest cationic charge potential. High transfection efficiency of PEI, along with its cytotoxicity, strongly depends on its molecular weight. To enhance its gene delivery efficiency and minimize cytotoxicity, we have synthesized small cross-linked PEI with biodegradable linkages and evaluated their transfection efficiencies in vitro. In this study, branched PEI with a molecular weight of 800 Da was cross-linked by small diacrylate [ 1,4-butanediol diacrylate or ethyleneglycol dimethacrylate （EGDMA）] for 2-6 h. The efficiencies of the cross-linked PEI in in vitro transfection of plasmid DNA containing enhanced green fluorescent protein （EGFP） reporter gene were assessed in melanoma B 16F10 cell line and other cell lines. Flow cytometry was used to quantify the cellular entry efficiency of plasmid and the transgene expression level. The cytotoxicities of the cross-linked PEI in these cells were evaluated by MTT assay. EGDMA-PEI 800-4h, a typical cross-linked PEI reported here, mediated a more efficient expression of reporter gene than the commercially available 25-kDa branched PEI control, and resulted in a 9-fold increase in gene delivery in B16F10 cells and a 16-fold increase in 293T cells, while no cytotoxicity was found at the optimized condition for gene delivery. Furthermore, the transfection activity of polyplexes was preserved in the presence of serum proteins.