Ligation-promoted hyperbranched rolling circle amplification enables ultrasensitive detection of microRNA in clinical specimens

MiRNA is reported as an important biomarker candidate and therapeutic target in a variety of diseases and cancers. However, ultrasensitive, straightforward, isothermal, low-cost and credible methods for the detection of miRNA from clinical specimens still remain challenges. Here, we establish an isothermal, highly sensitive and specific method for miRNA analysis based on a novel ligation-promoted hyperbranched rolling circle amplification (L-HRCA). This strategy exhibits 10(3)-fold sensitivity enhancement compared to T4 ligase-assisted targetprimer BRCA. The excellent specificity of L-HRCA allows for discriminating target miRNA from negative miRNAs. This method is applied to analyse the expression level of miR-21 in hepatocellular carcinoma. These results indicated that the L-HRCA strategy will become a promising tool to quantify miRNA in early clinical diagnostics.