Target-fueled catalytic hairpin assembly for sensitive and multiplex microRNA detection.

As a typical strand displacement-based DNA circuit, the catalytic hairpin assembly (CHA) has the potential to transduce and amplify signals for analytical applications, but little practice has been fulfilled in Luminex-based multiple microRNAs (miRNAs) detection. Here, we proposed a target-fueled CHA-based platform for sensitive and multiple miRNAs detection, by virtue of the multiplex characteristic of the Luminex xMAP platform. The cyclic use of target miRNA, which forms a substantial amount of H1-H2 duplexes, has amplified the fluorescent response to achieve sensitive sensing. Key experimental conditions including hairpin probe concentrations, reaction temperature, and concentration of SA-PE were optimized. Liver tumor-related miRNA-21, miRNA-122, and miRNA-222 could be simultaneously detected with LOD of 2 pM. Overall, the proposed method first combined CHA with the Luminex xMAP system to construct a sensitive sensing platform suitable for multiple miRNAs detection in real sample analysis, which could potentially be applied in biomedical research and clinical diagnosis. Graphical abstract.