Inter-particle DNA walker amplification coupled with target self-convert for sensitive detection of multiple miRNA by liquid chromatography†

Abnormal expression of microRNAs (miRNAs) is commonly considered as an indicator of various physical conditions. To address the separation and quantification of multiple miRNAs, an inter-particle DNA walker amplification coupled with a target self-convert system is developed for simultaneous and sensitive detection of three miRNAs by high-performance liquid chromatography (HPLC). In this work, one DNA-functionalized particle can walk around the other to produce abundant short probes realizing self-conversion of target miRNAs for detection of different short probes. This assay method shows detection limits of 1.5 fM for miRNA-21, 2.1 fM for miRNA-199a and 1.8 fM for miRNA-499. Furthermore, this method demonstrates the capability to selectively discriminate target miRNAs from interfering RNAs, ensuring high specificity under complex experimental conditions. The approach also exhibits exceptional sensitivity, allowing for the detection of low concentrations of target miRNA in human serum samples. With the successful application of this approach to three specific miRNAs, this technique can be further extended to detect other miRNAs in a convenient and efficient way.