Several studies have demonstrated the ability of graphene oxide (GO) to efficiently adsorb small-interfering RNA (siRNA) on its surface and to transport it into cells. However, studies on whether and how siRNA interacts with GO are still inconclusive. In this context, understanding the interaction between GO and siRNA is fundamental to design new efficient gene silencing tools. In this work, the interactions between GO and siRNA molecules were systematically investigated. We focused on how the GO size, oxygenated groups present on the surface and chemical functionalization affect the double helix siRNA structure, using gel electrophoresis, UV-Vis spectroscopy, fluorescence resonance energy transfer (FRET) and circular dichroism (CD). We found that the siRNA secondary structure was clearly altered by the interaction with GO flakes. In addition, we were able to correlate the double strand damage with the size and the oxygenated groups present on the GO sheets. Finally, we demonstrated that GO functionalized with low molecular weight polyethyleneimine (PEI, 800 Da) is able to protect siRNA from structural modifications. We believed that this research effort will improve our understanding of the behavior of GO/siRNA complexes, and thus facilitate the design of appropriate bio/nanointerfaces and new efficient gene silencing systems.

中文翻译：

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氧化石墨烯的大小和氧化程度控制其超分子相互作用的siRNA †

多项研究表明，氧化石墨烯（GO）能够有效吸附表面上的小干扰RNA（siRNA）并将其转运到细胞中。但是，关于siRNA是否与GO相互作用以及如何相互作用的研究尚无定论。在这种情况下，了解GO和siRNA之间的相互作用是设计新型高效基因沉默工具的基础。在这项工作中，系统地研究了GO和siRNA分子之间的相互作用。我们使用凝胶电泳，UV-Vis光谱，荧光共振能量转移（FRET）和圆二色性（CD）研究了GO的大小，表面上存在的氧化基团和化学功能化如何影响双螺旋siRNA的结构。我们发现，与GO薄片的相互作用明显改变了siRNA的二级结构。此外，我们能够将双链损伤与GO片材上的大小和含氧基团相关联。最后，我们证明了用低分子量聚乙烯亚胺（PEI，800 Da）功能化的GO能够保护siRNA免受结构修饰。我们相信，这项研究工作将增进我们对GO / siRNA复合物行为的理解，从而有助于设计适当的生物/纳米界面和新型有效的基因沉默系统。