Ultrasensitive photoelectrochemical biosensor for MiRNA-21 assay based on target-catalyzed hairpin assembly coupled with distance-controllable multiple signal amplification.

Here, with the target-catalyzed hairpin assembly generated dsDNA (HP1-HP2) to synchronously control the departure of quencher ferrocene and approach of sensitizer methylene blue, a distance-controllable multiple signal amplification based photoelectrochemical biosensor was proposed for MiRNA-21 assay.