Electrochemically driven assembly of framework nucleic acids

Abstract

• The utilization of an electrochemical chip to synthesis DNA nanostructures was firstly developed. • Tetrahedron DNA nanostructures of different sizes (20 bp, 26 bp and 37 bp) and octahedral DNA nanostructure were successfully assembled within 6 min. • The prepared DNA nanostructures exhibit the same structural characteristics and electrochemical performance in comparison to the ones fabricated with thermal annealing method. • The relations between electric potential and pH value were built. Electrochemically controlled synthesis of small molecules, DNA and various nanostructures provided unparalleled advantages to remotely control chemical reactions with high spatial and temporal precision. Although electrochemistry has been reported to actuate the reversible movement of DNA switch or tune the formation of hydrogen bonds in double strand DNA, electrochemically driven formation of DNA nanostructures remains a challenge as the result of their three-dimensional shapes and complex DNA folding pathway. Herein, through integrating a microfabricated chip with three-electrode system, we reported an electrochemical method to control the formation of tetrahedral DNA nanostructures. Using this method, the relation between the potential and solution pH value, and the melting temperature of double strand DNA was built, which facilitates synthesis of the tetrahedron DNA nanostructures in 6 min. Structure characterization of the prepared DNA nanostructures with atomic force microscopy (AFM) proved the physical integrity of the prepared DNA structures. By modifying the prepared DNA structure on the gold electrodes, a DNA nanostructure-based electrochemical biosensor with high sensitivity toward target DNA was fabricated. Based on these advantages, this method holds promise to develop high-throughput electrochemical microdevices capable of in-situ production of DNA nanostructures and the consequent multichannel biosensing.