DNA Triangular Pyramid Frustum Supported miR-21 Assay with Duplex-Specific Nuclease-Assisted Target Recycling

MicroRNAs (miRNAs) have the potential to be applied as effective biomarkers for early diagnosis of cancers. Electrochemical techniques exhibit advantages such as high sensitivity and ease of miniaturization. However, electrode interface perturbations may hinder electrochemical responses. To address the limitation, three-dimensional DNA triangular pyramid frustum nanostructures are designed on the surface of the electrode to support miRNA (miR-21 as an example) recognition and following target recycling. Due to the combination of DNA nanostructures and enzyme-mediated signal amplification, the sensitivity and selectivity of this electrochemical biosensor are enhanced. It also performs satisfactorily in human samples, which meets clinical detection requirements. Overall, the strategy provides new possibilities for accurate and reproducible miRNA assays and shows great potential applications in early disease diagnosis.