Colorimetric PCR-Based microRNA Detection Method Based on Small Organic Dye and Single Enzyme.

microRNAs (miRNAs) have been a class of promising disease diagnostic biomarkers and therapeutic targets for their important biological functions. However, because of the high homology, interference from precursors (pri-miRNA, pre-miRNA), as well as limitations in the current assay technologies, it poses high demand and challenge for a specific, efficient, and economic miRNA assay method. Here, we propose a new miRNA detection method based on a label-free probe and a small organic dye with sequence dependence, realizing the sequence-specific and colorimetric detection of target miRNA. What is pleasantly surprising, only one enzyme is enough to propel the whole miRNA assay process, greatly simplifying the reaction component and detection process. Together with PCR amplification for the high enough sensitivity and three checks for specificity control, a detection limit of 5 fM was obtained and even one mutation could be discriminated visually. Overall, the new method makes much progress in convenience and economy of PCR-based miRNA assay method so that miRNA assay is going to be more friendly and affordable.