Although in a series of studies, arginine peptides had shown the ability to promote the targeting delivery efficacy, the relationship between the transfection efficiency and the length of the poly‐l‐arginine chain had seldom been reported. This study was aimed to explore whether the chain length of poly‐l‐arginine grafted on chitosan had a great significance on the transfection efficiency of entering the cells. Herein, arginine and arginine peptide modified chitosan were synthesized as gene vectors (CS‐Arg and CS‐5Arg) and then the chemical structures were characterized by using ¹H NMR. The CS‐Arg and CS‐5Arg were combined with plasmids by electrostatic interactions to form stable particles. The morphology features, Zeta potentials, and buffering capacity of the complex particles were analyzed. Afterward, the combination ability with DNA and the protection ability to DNase I were studied, and the gene transfection efficiency and cellular uptake were investigated in vitro. The results showed that the gene transfection efficiency of the chitosan was significantly enhanced by arginine‐graft modification. However, there were no significant differences between the CS‐Arg and the CS‐5Arg. The molecular simulation results indicated that the guanidine groups of grafted arginine were shielded by chitosan molecule and the guanidine groups contributed little to the gene transfection efficiency. The results demonstrated that the increased chain length of grafted arginine had no significantly enhanced effect on the transfection efficiency, which could provide convincing evidence for the construction and application of arginine and chitosan derivatives as gene vectors, and could promote the development of gene delivery system.

中文翻译：

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聚-L-精氨酸肽修饰壳聚糖基因载体转染效率研究。

尽管在一系列研究中，精氨酸肽已显示出促进靶向递送功效的能力，但很少报道转染效率与聚-L-精氨酸链长度之间的关系。本研究旨在探讨接枝在壳聚糖上的聚-L-精氨酸的链长是否对进入细胞的转染效率有重要意义。在此，合成精氨酸和精氨酸肽修饰壳聚糖作为基因载体（CS-Arg 和 CS-5Arg），然后使用¹核磁共振。CS-Arg和CS-5Arg通过静电相互作用与质粒结合形成稳定的颗粒。分析了复合颗粒的形态特征、Zeta 电位和缓冲能力。随后，研究了与DNA的结合能力和对DNase I的保护能力，并在体外研究了基因转染效率和细胞摄取。结果表明，精氨酸移植物修饰显着提高了壳聚糖的基因转染效率。然而，CS-Arg 和 CS-5Arg 之间没有显着差异。分子模拟结果表明，接枝精氨酸的胍基被壳聚糖分子屏蔽，胍基对基因转染效率的贡献很小。