A Triple Signal Amplification Strategy for Accurate and Ultrasensitive miRNA-21 Detection

A triple signal amplification strategy was integrated with a built-in double electrode and external energy storage device to fabricate a novel self-powered biosensor for ultrasensitive detection of miRNA-21. Specifically, DNA tetrahedra and haripin2-glucose oxidase are modified on the surface of the biocathode and bioanode by catalytic hairpin assembly (CHA) to achieve dual signal amplification. Moreover, triple signal amplification is realized by including an external capacitor. Consequently, the as-constructed self-powered biosensor demonstrates a low detection limit of 0.06 fM toward the miRNA-21 assay within the range of 0.1 fM to 10 pM. This study presents a practical and sensitive approach to timely cancer detection.