A microchip electrophoresis-assisted triple-cycle cascade chemiluminescence signal amplification strategy for the ultrasensitive detection of microRNA-141 in cells

Based on the microchip electrophoresis chemiluminescence detection (MCE-CL) platform, an ultrasensitive method was developed for the detection of microRNA-141 (miRNA-141) by using T7 exonuclease (T7 Exo)assisted triple-cycle cascade chemiluminescence signal amplification strategy. In this method, the horseradish peroxidase (HRP)-labeled single strand DNA (HRP-DNA) was used as a signal probe for the cascade signal amplification identification of miRNA-141 in cancer cells. Under the optimized experimental conditions, the chemiluminescence intensity and logarithm of the miRNA-141 concentration showed a good linear relationship. The detection limit for miRNA-141 assay reached 9.1 x 10-17 M (S/N = 3). This method displayed excellent specificity for differentiating miRNAs with base mismatch, and was applied to determine miRNA-141 in the lysates of cancer cells. This method shows important applications when using limited amounts of biological samples for clinical diagnostics and biomedical research of miRNAs.