Ultrasensitive assay of ctDNA based on DNA triangular prism and three-way junction nanostructures

Circulating tumor DNA (ctDNA) refers to a class of acellular nucleic acids carrying genetic features of primary tumor, which can be regarded as a promising noninvasive biomarker for cancer diagnosis. The development of ctDNA assay is an important component of liquid biopsy. In this study, we have fabricated a novel electrochemical strategy for ultrasensitive detection of ctDNA combining the merits of strand displacement amplification and DNA nanostructures. Stable DNA triangular prism is firstly self-assembled and modified on the electrode surface. After target initiated strand displacement polymerization reaction, the generated DNA product helps the formation of three-way junction nanostructure on triangular prism, which localizes electrochemical species. By carefully investigating the electrochemical responses, the limit of detection (LOD) for ctDNA assay as low as 48 amol/L is achieved. This proposed electrochemical biosensor shows great potential for clinical applications. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

A novel electrochemical strategy combining strand displacement amplification and DNA nanostructures was developed for ultrasensitive detection of ctDNA, achieving a limit of detection as low as 48 amol/L. This proposed electrochemical biosensor shows great potential for clinical applications.