An electrochemical approach for detection of specific DNA-binding protein by gold nanoparticle-catalyzed silver enhancement.

Interaction between transcription factor and sequence-specific DNA plays an important role in regulation of gene transcription in biological systems. As electrochemical intercalators, gold (Au) nanoparticles show high catalysis activity and compatibility for detection of biological molecules. In this article, we report an electrochemical approach for sequence-specific DNA-binding transcription factor detection by Au nanoparticle-catalyzed silver (Ag) enhancement at interface between electrodes and electrolyte solutions. Here unimolecular hairpin oligonucleotides were self-assembled onto Au electrode surface and their elongation on Au electrode surface was carried out to form double-stranded oligonucleotides with transcription factor NF-kappaB (nuclear factor-kappa B) binding sites. Au nanoparticle-catalyzed Ag deposition was detected by anodic stripping voltammetry (ASV) for NF-kappaB binding. It was found that this method for the detection of sequence-specific DNA-binding protein showed pronounced specificity and that the detection limit was as low as 0.1 pM. The findings indicated that our method can have applications in transcription regulation, operator site recognition, and functional gene inspection.