Simultaneous electrochemical determination of two analytes based on nuclease-assisted target recycling amplification

In the present study, a method for simultaneous determination of two different DNAs is developed based on nuclease-assisted target recycling and nanoparticle amplification. The target recycling process is accomplished by taking advantage of the cleavage property of nicking endonuclease (NEase) for specific nucleotide sequences in duplex. In the presence of target DNA, the linker DNA in our detection system can hybridize with the target and be cleaved to form short fragments. Thus the target DNA is released and recognized by another linker DNA, activating the next round of cleavage reaction. On the other hand, two bio-barcode probes, a PbS nanoparticles (NPs)-DNA probe and a CdS NPs-DNA probe, are used for tracing two target DNAs to further amplify the detection signals. Based on a sensitive differential pulse anodic stripping voltammetry (DPASV) method for the simultaneous detection of Pb(2+) and Cd(2+) obtained by dissolving two probes, two different target DNAs are determined with high sensitivity and single-base mismatch selectivity.