Electrochemical ultrasensitive detection of miRNA-21 via RAFT/ROMP dual polymerization amplification

M and reaches a detection limit as low as 4.72 aM. Signals from single-mismatched RNA, triple-mismatched RNA, and miRNA-320b were all strongly suppressed relative to the target, while the sensor also proved to be stable in one week and remarkably unfazed by complex biological backgrounds.