Y-shaped walker with abundant recognition domians mediated ultrasensitive electrochemical biosensor for miRNA-21 detection

Herein, an ultrasensitive electrochemical biosensor was constructed by a high-efficiency Y-shaped walker with abundant recognition domains (YSWARD) for microRNA-21 (miRNA-21) detection. Once target miRNA-21 induced the assembly of Y-shaped DNA nanostructure (YSDN) through a catalytic hairpin assessbly (CHA), amounts of the YSWARD could be synthesized with the assistance of padlock via rolling circle amplification (RCA). Impressively, the YSWARD exhibited much higher cleavage efficiency (2.81 × 10 9 ) which was at least ten times more than that of conventional Y-shaped walker with three recognition domains (2.36 × 10 8 ). As a proof of concept, the YSWARD was adopted to construct electrochemical biosensing platform that achieved ultrasensitive detection with a detection limit of 10.6 aM for target miRNA-21, which carved out promising potential for exploring novel DNA walker platforms to apply in sensitive detection of biomarkers and early diagnosis of diseases. An electrochemical biosensor was developed based on high cleavage efficiency Y-shaped walker with abundant recognition domains (YSWARD) for the sensitive detection of target miRNA-21. • A novel electrochemical biosensor was constructed based on the proposed high-efficient walker. • A 10-fold enhanced cleavage efficiency was acquired through the proposed strategy. • Target recycle amplification strategy was adopted to achieve sensitive detection of miRNA-21. • This biosensor displayed wide linear range with a detection limit as low as 10.6 aM.