Division of Chemistry and Ionizing Radiation Measurement Technology, Shanghai Institute of Measurement and Testing Technology, Shanghai 201203, China.
Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Anal Chem. 2020 Mar 17;92(6):4498-4503. doi: 10.1021/acs.analchem.9b05616. Epub 2020 Mar 3.
MicroRNAs (miRNAs) have been explored as biomarkers for early diagnosis of diseases like cancers. However, it remains challenging to detect low-level miRNAs in the total RNA from real samples in a facile approach. In this work, we report a two-phase miRNA biosensing strategy based on a modular framework nucleic acid (FNA) platform, which combines the high efficiency of homogeneous reaction and the convenience of heterogeneous biosensing. In the first phase, free DNA probes bind target miRNAs in a homogeneous solution, forming a DNA-RNA complex with high base stacking energy. Then, at the second phase, the universal FNA interface on the electrode selectively mediated the transition of the complex from the solution onto the interface for electrochemical signal generating and transduction. By applying this method, we detected as few as 1 aM of miR-141, a cancer marker miRNA, without the need for nucleic acid amplification. The dynamic range spans 10 orders of magnitude. We demonstrate multiplex miRNA detection and discrimination of highly homologous miRNAs with mismatches as few as a single base. We also show that this system can detect miR-141 in only 50 ng of total RNA samples from real cells, which allows discrimination of prostate cancer cells with normal cells. We envision this platform may satisfy the need for facile and high-throughput screening of early cancer markers.
微小 RNA（miRNAs）已被探索作为癌症等疾病早期诊断的生物标志物。然而，以简单的方法在实际样本的总 RNA 中检测低水平的 miRNAs 仍然具有挑战性。在这项工作中，我们报告了一种基于模块化核酸（FNA）平台的两阶段 miRNA 生物传感策略，该策略结合了均相反应的高效率和异相生物传感的便利性。在第一阶段，游离 DNA 探针在均相溶液中与靶 miRNAs 结合，形成具有高碱基堆积能的 DNA-RNA 复合物。然后，在第二阶段，电极上通用的 FNA 界面选择性介导复合物从溶液向界面的转变，用于电化学信号的产生和转导。通过应用这种方法，我们检测到低至 1 aM 的 miR-141（一种癌症标志物 miRNA），而无需核酸扩增。动态范围跨越 10 个数量级。我们证明了可以对高度同源的 miRNA 进行多重 miRNA 检测和区分，其错配仅为单个碱基。我们还表明，该系统可以仅从实际细胞的 50ng 总 RNA 样本中检测到 miR-141，从而可以区分前列腺癌细胞和正常细胞。我们设想该平台可以满足对早期癌症标志物进行简便和高通量筛选的需求。
