Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Blvd., Nanshan District, Shenzhen, Guangdong 518055, P. R. China.
Nanoscale. 2018 Apr 19;10(15):7067-7076. doi: 10.1039/c8nr00364e.
The design of a nano-system for the detection of intracellular microRNAs is challenging as it must fulfill complex requirements, i.e., it must have a high sensitivity to determine the dynamic expression level, a good reliability for multiplex and simultaneous detection, and a satisfactory biostability to work in biological environments. Instead of employing a commonly used physisorption or a full-conjugation strategy, here, a GO-DNA nano-system was developed under graft/base-pairing construction. The common anchor sequence was chemically grafted to GO to base-pair with various microRNA probes; and the hybridization with miRNAs drives the dyes on the probes to leave away from GO, resulting in "turned-on" fluorescence. This strategy not only simplifies the synthesis but also efficiently balances the loading yields of different probes. Moreover, the conjugation yield of GO with a base-paired hybrid has been improved by more than two-fold compared to that of the conjugation with a single strand. We demonstrated that base-paired DNA probes could be efficiently delivered into cells along with GO and are properly stabilized by the conjugated anchor sequence. The resultant GO-DNA nano-system exhibited high stability in a complex biological environment and good resistance to nucleases, and was able to accurately discriminate various miRNAs without cross-reaction. With all of these positive features, the GO-DNA nano-system can simultaneously detect three miRNAs and monitor their dynamic expression levels.
设计用于检测细胞内 microRNA 的纳米系统具有挑战性，因为它必须满足复杂的要求，即必须具有高灵敏度以确定动态表达水平、良好的可靠性以进行多重和同时检测，以及令人满意的生物稳定性以在生物环境中工作。与通常使用的物理吸附或完全共轭策略不同，这里采用接枝/碱基配对构建方法开发了 GO-DNA 纳米系统。将常见的锚序列化学接枝到 GO 上，与各种 microRNA 探针碱基配对；与 miRNA 的杂交导致探针上的染料远离 GO，从而产生“开启”荧光。这种策略不仅简化了合成，而且有效地平衡了不同探针的加载产率。此外，与单链相比，与碱基配对杂交的 GO 的共轭产率提高了两倍以上。我们证明，带有碱基配对 DNA 探针的 GO 可以有效地与 DNA 探针一起递送到细胞中，并通过共轭的锚序列得到适当的稳定。所得的 GO-DNA 纳米系统在复杂的生物环境中表现出高稳定性和对核酸酶的良好抗性，并且能够准确区分各种 miRNA 而不会发生交叉反应。具有所有这些积极特征，GO-DNA 纳米系统能够同时检测三种 miRNA 并监测它们的动态表达水平。
