Electrochemical impedance spectroscopic analysis of nucleic acids through DNA tetrahedron self-walking machine

Abstract

The design of artificial molecular machines has attracted great interest in recent years. Herein, a DNA tetrahedron self-walking machine is constructed for the application of label-free electrochemical detection of nucleic acids. After target DNA initiated conformation change, autonomous walking is achieved around the DNA tetrahedron, which is powered by nicking endonuclease (NEase). Further hybridization with thiolated auxiliary probe facilitates the immobilization of the DNA nanostructure on the gold electrode interface. After a simple electrochemical impedance spectroscopic analysis, the calculated interfacial resistance (Rct) is found to be linearly related to logarithmic concentration of target nucleic acids in the range from 10 fM to 10 pM with a limit of detection at 3.7 fM. Furthermore, the proposed method has been successfully applied in human blood serum samples, demonstrating great potential practical utility.