关键词: 小干扰RNA, 递送, 纳米粒, 制备工艺, 细胞摄取

Abstract:

In this study, a gemini-like cationic lipid (CLD) was used as the carrier to study the complexation features of CLD/siRNA nanoplexes (CLD/siRNA NPs). Three types of CLD/siRNA nanoplexes (named as AT NPs, HT NPs and MT NPs) were prepared by different processes: AT method (mixing siRNA solution with preformed CLD nanoparticles), HT method (hydrating a CLD thin film with siRNA solution), and MT method (dropping an ethanolic solution of CLD into siRNA solution under sonication). The particle size, zeta potential, morphology, siRNA protection, cytotoxicity, cellular uptake, and targeted mRNA down-regulation were studied. At the optimal N/P ratio of 10, the sizes of the three CLD/siRNA NPs were MT NPs ((222.3±19.1) nm)> HT NPs ((105.7±1.31) nm)>AT NPs ((91.8±1.75) nm). Different nanostructures were formed despite the fact that they were composed of the same components. Furthermore, the TEM images indicated that different morphologies were found in the three NPs, indicating that the nanoplexes were assembled by different mechanisms. Among the three NPs, the cell uptake capacity were as follows: AT NPs>MT NPs>HT NPs, whereas the silencing levels on epidermal growth factor receptor (EGFR) in HeLa cells were MT NPs>AT NPs>HT NPs. Based on the above results, we hypothesized that the different preparation processes resulted in nanostructures with varying biological effects. Therefore, we believe that structural optimization of siRNA nanoplexes is essential in achieving better siRNA encapsulation, protection, and gene silencing efficiency.  

Key words: siRNA, Delivery, Nanoparticles, Preparation, Cellular uptake