An electric potential modulated cascade of catalyzed hairpin assembly and rolling chain amplification for microRNA detection.

MicroRNAs serve as a new type of biomarker for multifarious diseases due to its critical roles in post transcriptional gene regulation. Herein, we firstly integrate the catalyzed hairpin assembly (CHA) and rolling circle amplification (RCA) into an electrochemical biosensor for sensitive and specific detection of miR-21. Meanwhile, an electric potential was employed to modulate the efficiency of CHA occurred on the electrode, which offer a simple but effective method to surmount the accessibility problem of probes. The biosensor achieved an ultrasensitive determination of miR-21 with a low limit of detection of 13.5 fM and a linear range from 15 fM to 250 pM. This research encourages us to challenge the hyphenated multiple amplification strategies and provides a stable and effective method for the detection of diseases-related miRNAs in peripheral biofluids, as well as paves a road for the future clinical diagnostics and treatment of disease.