ABSTRACT

Polyethyleneimine (PEI) is a non-viral gene vector of frequent concern because of its high transfection efficiency. However, its clinical application is limited by the cytotoxicity caused by high positive charge density. Therefore, reducing toxicity and maintaining high transfection efficiency through appropriate strategies are of great significance to promote the development of PEI as gene vector. In order to reduce the toxicity of PEI, this work studied the feasibility of encapsulating PEI/DNA complexes by using the coordination between tannic acid (TA) and metal ions (Mⁿ⁺). Firstly, TA formed a coating layer on the surface of PEI/DNA complex through electrostatic action, and then the quaternary complex (Mⁿ⁺(TA/PEI/DNA)) system was prepared by the coordination between metal ions and TA. In order to better construct a gene delivery system with high transfection efficiency and low toxicity, the effects of PEI molecular weight, mass ratio of PEI/DNA, mass ratio of TA, and types of metal ions on the transfection efficiency, cytotoxicity, particle size, zeta potential, and cell uptake pathway of the quaternary complex were studied. The results showed that the quaternary complex based on PEI70k and encapsulated by coordination between TA and potassium ions showed better safety than PEI70k/DNA while maintaining high transfection efficiency. This showed that the strategy of coordination encapsulation of TA and ions to improve the safety of PEI as gene carrier is feasible, which provides a new reference for the design of gene delivery system based on PEI.

摘要

聚乙烯亚胺 (PEI) 是一种经常受到关注的非病毒基因载体，因为它具有高转染效率。然而，其临床应用受到高正电荷密度引起的细胞毒性的限制。因此，通过适当的策略降低毒性并保持较高的转染效率，对于促进PEI作为基因载体的发展具有重要意义。为了降低PEI的毒性，本工作研究了利用鞣酸(TA)和金属离子(M ⁿ⁺ )之间的配位作用来包裹PEI/DNA复合物的可行性。首先，TA通过静电作用在PEI/DNA复合物表面形成一层包被层，进而形成四元复合物（M ⁿ⁺(TA/PEI/DNA))体系是通过金属离子与TA配位制备的。为了更好地构建转染效率高、毒性低的基因递送系统，研究了PEI分子量、PEI/DNA质量比、TA质量比、金属离子种类对转染效率、细胞毒性、粒径的影响。研究了四元复合物的 、zeta 电位和细胞摄取途径。结果表明，基于 PEI70k 并通过 TA 和钾离子配位包封的四元复合物在保持高转染效率的同时，表现出比 PEI70k/DNA 更好的安全性。这表明TA与离子协同包封提高PEI作为基因载体安全性的策略是可行的，为基于PEI的基因递送系统设计提供了新的参考。