Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China.
Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, China.
Talanta. 2017 Nov 1;174:679-683. doi: 10.1016/j.talanta.2017.07.008. Epub 2017 Jul 1.
An interference-free and label-free sensing platform was developed for the highly sensitive detection of microRNA-21 (miRNA-21) in vitro by magnetic silicon microsphere (MNP)-reduced graphene oxide (rGO)-based sandwich probe. In this method, DNA capture probes (P) were connected with MNPs at the 5' end and hybridized with completely complementary target miRNA. Subsequently, rGO was retained and induced the fluorescence quenching in the supernatant. Through the magnetic separation, the supernatant environment was simplified and the interference to analytical signal was eliminated. When DNA capture probe-modified magnetic silicon microspheres (MNP-P) were adsorbed through rGO in the absence of a target and formed a sandwich structure, the formed nanostructure was easily removed from the solution by a magnetic field and the fluorescence intensity was maximally recovered. This proposed strategy, which both overcame the expensive and cumbersome fluorescent labeling, and eliminated interference to analytical signal for guaranteeing high signal-to-background ratio, exhibited high sensitivity with a detection limit as low as 0.098nM and special selectivity toward miRNA-21. The method was potentially applicable for not only detection of miRNA-21 but also various biomarker analyses just by changing capture probes.
本研究开发了一种无干扰、无标记的传感平台，通过基于磁性硅微球（MNP）-还原氧化石墨烯（rGO）的三明治探针，实现了体外高灵敏度检测 microRNA-21（miRNA-21）。在该方法中，DNA 捕获探针（P）通过 5' 端与 MNPs 连接，并与完全互补的靶 miRNA 杂交。随后，rGO 被保留下来并诱导上清液中的荧光猝灭。通过磁分离，简化了上清液环境，消除了对分析信号的干扰。当不存在靶标时，通过 rGO 吸附 DNA 捕获探针修饰的磁性硅微球（MNP-P）并形成三明治结构时，所形成的纳米结构很容易通过磁场从溶液中去除，荧光强度最大程度地恢复。该策略不仅克服了昂贵且繁琐的荧光标记，还消除了对分析信号的干扰，保证了高信噪比，具有 0.098nM 的检测限和对 miRNA-21 的特殊选择性。该方法不仅可用于检测 miRNA-21，还可通过改变捕获探针用于各种生物标志物分析。
