A double signal amplification electrochemical MicroRNA biosensor based on catalytic hairpin assembly and bisferrocene label

MicroRNA is crucial for post-transcription gene regulation and is a new type of biomarker for many diseases. Herein, we synthesized a novel bisferrocene biomarker, which was placed at both ends of hairpin DNA, generating a probe of high-efficiency amplification signal. Our method entailed the integration of the catalytic hairpin assembly (CHA) and bisferrocenes into a double-amplified signal electrochemical miRNA biosensor. The biosensor achieved ultra-sensitive detection of miRNA-21 with a minimum detection limit of 0.1 f. and linear range of 0.2 f. ~ 0.2 nM. This study provides an effective detection way for miRNA, and opens new possibilities for future clinical diagnosis and treatment of diseases.