Target-Triggered Enzyme-Free Amplification Strategy for Sensitive Detection of MicroRNA in Tumor Cells and Tissues

MicroRNAs (miRNAs) participate in important processes of life course. Because of their characters of small sizes, vulnerable degradabilities, and sequences similarities, the existing detection technologies mostly contain enzymatic amplification reactions for acquisition of high sensitivities and specificities. However, specific reaction conditions and time-dependent enzyme activities are caused by the accession of enzymes. Herein, we designed a target-triggered enzyme-free amplification platform that is realized by circulatory interactions of two hairpin probes and the integrated electrochemiluminescence (ECL) signal giving-out component. Benefiting from outstanding performances of the enzyme-free amplification system and ECL, this strategy is provided with a simplified reaction process, high sensitivity, and operation under isothermal conditions. Through detection of the miRNA standard substance, the sensitivity of this platform reached 10 fmol, and a splendid specificity was achieved. We also analyzed three tumor cell lines (human lung adenocarcinoma, breast adenocarcinoma, and hepatocellular liver carcinoma cell lines) through this platform. The sensitivities of 103 cells, 104 cells, and 104 cells were, respectively, achieved. Furthermore, clinical tumor samples were tested, and 21 of 30 experimental samples gave out positive signals. Thus, this platform possesses potentials to be an innovation in miRNA detection methodology.