Three dimensional DNA nanotracks: A novel method for ultrasensitive and visible mercury (II) detection

Three Dimensional DNA nanotracks (3D DNA Nanotracks) based on Hg (II)-responsive exponential amplification reaction (EXPAR) integrated with DNA hydrogels for ultrasensitive and visual Hg (II) detection were developed. The 3D DNA Nanotracks could be successfully installed in the presence of Hg (II). Briefly, Hg (II) triggered the EXPAR reaction and produced substantial amounts of single-stranded DNA (ssDNA). The ssDNA as the initiator stimulated the visual DNA hydrogel, which trapped gold nanoparticles (AuNPs) in its networks. Therefore, Hg (II) could be visually determined using the Hg (II)-responsive EXPAR for the signal amplification, identification, and transformation. The hydrogel was used as the visual and quantitative readout, and the limit of detection (LOD) of the biosensor was determined to be as low as 2.8 pM.