Construction of Y-shaped multivalent DNA walker system for sensitive detection of circulating tumor DNA.

Abstract

A stimulus-responsive Y-shaped multivalent DNA walker system has been developed for highly sensitive circulating tumor DNA (ctDNA)​ detection by integrating catalytic hairpin assembly (CHA)-mediated Y-shaped DNA self-assembly with an endonuclease-assisted three-dimensional DNA walking strategy. The system was constructed using functional hairpin probes and DNA walker tracks. In the presence of ctDNA, CHA was initiated to generate multivalent Y-shaped DNA nanostructures containing dual endonuclease-responsive branches, which subsequently activated DNA walking and generated amplified signals through enzymatic cleavage. The combination of CHA and DNA walking enabled cascade dual signal amplification and improved detection performance. Thus, the Y-shaped multivalent DNA walker system allow the sensitive and selective sensing toward ctDNA with the detection linear range varied from 500 fM to 1µM and the detection limit as low as 243 fM. Furthermore, the system was applied for the detection of the addition and recovery of ctDNA in diluted human serum samples for 3 days, the mean recoveries​ of the system range​ from 98.59% to 101.61%. The intra-day RSDs ranging from 1.01% to 3.57% and inter-day RSDs ranging from 3.06% to 3.55% indicate that the strategy exhibits good stability and accuracy. The proposed strategy provides a structurally stable and efficient DNA nanomachine platform for ctDNA detection and offers a sensitive molecular tool with potential applications in biosensing and biological research.

Abstract as supplied by the indexing source. © the authors / publisher.