Direct microRNA detection with universal tagged probe and time-resolved fluorescence technology.

microRNAs have emerged as the central player in gene expression regulation and have been considered as potent cancer biomarkers for early disease diagnosis. Direct microRNA detection without amplification and labeling is highly desired. Here we present a rapid, sensitive and selective microRNA detection method based on the base stacking hybridization coupling with time-resolved fluorescence technology. Other than planar microarrays, magnetic beads are used as reaction platforms. In this method, one universal tag is used to report all microRNA targets. Its specificity allows for discrimination between microRNAs differing by a single nucleotide, and between precursor and mature microRNAs. This method also provides a high sensitivity down to 20 fM. Moreover, the full protocol can be completed in about 3 h starting from total RNA. Copyright Â