Abstract: Authors report on the detection of DNA hybridization using electrochemistry method. The target ss-DNA was immobilized on glassy carbon electrode and hybridized with the gold nanoparticle-oligonucleotide DNA probe. A nanoparticle-promoted Ag precipitation was used to enlarge the nanoparticle tag, forming the Au/Ag core-shell structure, followed by the release of the silver metal atoms anchored on the hybrids by oxidative metal dissolution and the indirect determination of the solubilized Ag ions by anodic stripping voltammetry (ASV) at a carbon fiber microelectrode. Further signal amplification, and lowering of the detection limits to the picomolar domains, was achieved by precipitating silver. The results show that this method has good correlation for detection of DNA in the range of 100～1 000 pmol•L－1and allows detection at levels as low as 10 pmol•L－1 of the target oligonucleotides.

Key words: DNA, Gold nanoparticle-oligonucleotide DNA probe, Hybridization, A nanoparticle-promoted Ag precipitation, Anodic stripping voltammetry (ASV)