Gene therapy is a promising strategy for treatments of various diseases. Efficient and safe introduction of therapeutic genes into targeted cells is essential to realize functions of the genes. High-molecular-weight polyethylenimines (HMW PEIs) including 25 kDa branched PEI and 22 kDa linear PEI are widely used for in vitro gene transfection. However, high-gene transfection efficiency is usually accompanied with high cytotoxicity, which hampers their further clinical study. On the contrary, low-molecular-weight polyethylenimines (LMW PEIs) such as 1.8 kDa PEI and 800 Da PEI show good biocompatibility but their applications are limited by the poor DNA condensation capability. In this study, we find that 1.8 kDa PEI, but not 800 Da PEI combined with low-dose 25 kDa PEI could significantly promote gene transfection with low cytotoxicity. Plasmids encoding enhanced green fluorescence protein (EGFP) were delivered by the combined PEI and gene transfection efficiency was evaluated by microscopic observation and flow cytometry. Parameters including concentrations of 25 kDa PEI and 1.8 kDa PEI and preparation ways were further optimized. This study presents an efficient and safe combined PEI-based non-viral gene delivery strategy with potential for in vivo applications.

中文翻译：

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低剂量的25 kDa聚乙烯亚胺借助1.8 kDa聚乙烯亚胺提高了基因转染效率。

基因疗法是治疗各种疾病的有前途的策略。有效和安全地将治疗性基因导入靶细胞对于实现基因功能至关重要。包括25 kDa支链PEI和22 kDa线性PEI的高分子量聚乙烯亚胺（HMW PEI）被广泛用于体外基因转染。然而，高基因转染效率通常伴随着高细胞毒性，这阻碍了它们的进一步临床研究。相反，低分子量聚乙烯亚胺（LMW PEI）（例如1.8 kDa PEI和800 Da PEI）显示出良好的生物相容性，但它们的应用受到不良的DNA缩合能力的限制。在这项研究中，我们发现1.8 kDa PEI，而不是800 Da PEI与低剂量25 kDa PEI结合可以显着促进基因转染，并且具有低细胞毒性。编码的绿色荧光蛋白（EGFP）的质粒通过组合的PEI传递，并通过显微镜观察和流式细胞术评估基因转染效率。进一步优化了25 kDa PEI和1.8 kDa PEI的浓度以及制备方法。这项研究提出了一种有效且安全的，基于PEI的非病毒基因联合给药策略，具有体内应用潜力。