CICS-UBI-Health Sciences Research Centre, University of Beira Interior, Avenida Infante D. Henrique, 6200-506 Covilhã, Portugal.
J Colloid Interface Sci. 2012 Dec 1;387(1):84-94. doi: 10.1016/j.jcis.2012.07.088. Epub 2012 Aug 21.
The purpose of the present study is to provide a tool for an efficient design and synthesis of non-viral vectors for small RNA delivery. The effects of properties of the polycation, such as molecular weight, charge density and backbone structure, to polyplex structure and physicochemical behavior were systematically evaluated. The condensing agents, polyethylenimine (PEI), chitosan (CS) and poly(allylamine) (PAA) were added to sRNA molecules at different N/P ratio. The efficiency of encapsulation and protection of sRNA, as well as polyplex size, zeta potential and morphology were followed and compared. The results show that PEI/sRNA polyplexes display a small size and positive zeta potential. However, for low molecular weights, this polycation is unable to protect sRNA in the presence of a decompacting agent. With chitosan, sRNA is efficiently compacted at high N/P ratios. The CS/sRNA complexes display small sizes, ca. 200 nm, positive surface charge and also good stability. Finally, the PAA/sRNA polyplexes were found to be the smallest at low N/P ratios, displaying a good encapsulation efficiency and high stability. A rationale for the experimental observations is provided using Monte Carlo simulation for systems with polycations of different length and charge density. The simulations showed that there is an interplay between the size of polycation chains and its charge density that define the degree of condensation for sRNA.
本研究的目的是提供一种有效的工具，用于设计和合成用于小 RNA 传递的非病毒载体。系统地评估了多阳离子的性质（如分子量、电荷密度和主链结构）对聚阳离子结构和物理化学行为的影响。缩合剂聚乙烯亚胺（PEI）、壳聚糖（CS）和聚（烯丙胺）（PAA）以不同的 N/P 比添加到 sRNA 分子中。跟踪并比较了 sRNA 的封装和保护效率、聚阳离子的大小、ζ 电位和形态。结果表明，PEI/sRNA 聚阳离子复合物的粒径小，ζ 电位为正。然而，对于低分子量的聚阳离子，在存在解压缩剂的情况下，它无法保护 sRNA。用壳聚糖，在高 N/P 比下，sRNA 被有效地压缩。CS/sRNA 复合物的粒径小，约 200nm，表面带正电荷，稳定性也较好。最后，PAA/sRNA 聚阳离子复合物在低 N/P 比下粒径最小，显示出良好的封装效率和高稳定性。使用不同长度和电荷密度的聚阳离子的蒙特卡罗模拟为实验观察提供了合理的解释。模拟表明，聚阳离子链的大小和电荷密度之间存在相互作用，这决定了 sRNA 的缩合程度。
