Accurate and reliable quantification of disease-related biomolecules is essential for clinical diagnosis. In this study, a novel electrochemical approach is developed based on a target triggered DNA nanostructural switch from a hairpin dimer to a double-stranded wheel. During the process, electrochemical species get closer to the electrode interface, and the multiple intramolecular strand displacements are beneficial to low abundant target analysis. In addition, the use of nicking endonuclease mitigates background interference. This strategy enables highly sensitive and selective quantification of the target miRNA. A linear relationship is established between the peak current intensity and the logarithm of miRNA concentration within the range from 0.1 to 20 fM. This method also demonstrates high accuracy in the analysis of clinical samples, holding great potential for DNA nanotechnology in diagnostic applications.
Keywords: DNA wheel; hairpin dimer; nicking endonuclease; square wave voltammetry; strand displacement.