Kapilov-Buchman Yekaterina, Lellouche Emmanuel, Michaeli Shulamit, Lellouche Jean-Paul
†Department of Chemistry, Faculty of Exact Sciences, ‡The Mina and Everard Goodman Faculty of Life Sciences, and §Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, 5290002 Israel.
Bioconjug Chem. 2015 May 20;26(5):880-9. doi: 10.1021/acs.bioconjchem.5b00100. Epub 2015 Apr 8.
The discovery of RNA interference (RNAi) as a naturally occurring mechanism for gene knockdown has attracted considerable attention toward the use of small interfering RNAs (siRNAs) for therapeutic purposes. The main obstacles of harnessing siRNAs as drugs are their inefficient delivery to cells and off-target effect making clinical applications very challenging. The positively charged, branched 25 kDa polyethylenimine (b-PEI) polymer is widely regarded as one of the most efficient nonviral commercially available transfection agents. However, it has also been shown that 25 kDa b-PEI is highly cytotoxic and can readily lead to cell death. In this specific context, this study presents the preparation and characterization of innovative 25 kDa b-PEI-decorated polycationic silica nanoparticles (SiO2 NPs) for cellular siRNA delivery and subsequent gene silencing. A new method of b-PEI attachment onto the SiO2 NP surface has been developed that makes use of cerium(III) cations (Ce(3+)), a lanthanide group element, as an effective noncovalent inorganic linker between both polyNH2-SiO2 nanoparticle (SPA NPs) surface and polycationic 25 kDa b-PEI polymer. Two resulting novel SPA-Ce-PEI NPs consist of similar amounts of b-PEI, while possessing different amounts of Ce(3+). Various analytical techniques (TEM, DLS, ζ potential, ICP-AES, and TGA) have been used to deeply characterize NPs physicochemical qualities. The observed results of Ce(3+)-dependent gene silencing and cytotoxic activities led us to conclusions about the role of Ce(3+)-N bonding during the chemical attachment of the 25 kDa b-PEI shell onto the NP surface.
RNA干扰（RNAi）作为一种天然存在的基因敲低机制被发现后，利用小干扰RNA（siRNA）进行治疗引起了广泛关注。将siRNA用作药物的主要障碍是其向细胞的递送效率低下以及脱靶效应，这使得临床应用极具挑战性。带正电荷的25 kDa支链聚乙烯亚胺（b-PEI）聚合物被广泛认为是最有效的非病毒市售转染剂之一。然而，也有研究表明，25 kDa的b-PEI具有高度细胞毒性，很容易导致细胞死亡。在这种特定背景下，本研究介绍了用于细胞siRNA递送及后续基因沉默的创新性25 kDa b-PEI修饰的聚阳离子二氧化硅纳米颗粒（SiO2 NPs）的制备与表征。已开发出一种将b-PEI附着到SiO2 NP表面的新方法，该方法利用镧系元素铈（III）阳离子（Ce(3+)）作为聚NH2-SiO2纳米颗粒（SPA NPs）表面与聚阳离子25 kDa b-PEI聚合物之间有效的非共价无机连接体。由此产生的两种新型SPA-Ce-PEI NPs含有相似量的b-PEI，但Ce(3+)的含量不同。已使用各种分析技术（透射电子显微镜、动态光散射、ζ电位、电感耦合等离子体发射光谱和热重分析）深入表征纳米颗粒的物理化学性质。Ce(3+)依赖性基因沉默和细胞毒性活性的观察结果使我们得出了关于Ce(3+)-N键在25 kDa b-PEI壳化学附着到NP表面过程中的作用的结论。
