Electrochemical detection of sequence specific DNA binding protein with gold nanoparticle-catalized Ag enhancement

The interactions between transcription factor and sequence specific DNAplay important roles in drug genome and transcription diagnosis. Gold nanoparticlesshow high sensitivity, stability and compatibility for biological molecules as electrochemical intercalators. NF-κB is a family of transcription factors that regulates a wide variety of biological processes such as inflammation, apoptosis, cell cycle control, cell migration and wide variety of cancers. There is no report of sequence specific DNA binding NF-κB detection by gold nanoparticle catalyzed Ag enhancement at the interface between electrodes and electrolyte solutions. Here unimolecular hairpin oligonucleotides were self-assembled onto Au electrode surface and elongation on solid phase was carried out to double strand oligonucleotides with transcription factor NF-κB binding site. The elongation of unimolecular hairpin oligonucleotides on Au electrodes was verified by incorporation of biotin labeled dUTP during the elongation followed by addition of gold nanoparticle labeled streptavidin and detection of anodic stripping voltammetry (ASV) signals of gold nanoparticle-catalyzed Ag deposition. Then gold nanoparticle-catalyzed Ag deposition was detected by ASV for NF-κB binding and the specificity of NF-κB binding and the detection limit were explored. It was resulted the detection low limit was as low as 0.1 pmol/L, which was five magnitude lower than the applied fluorescence method for DNA-protein interactions detection on the aldehyde-coated glass slides. It was indicated that this new method for sequence specific DNA binding protein detection showed pronounced specificity, sensitivity and could find application to transcription regulation research, open reading frame characterization and functional gene inspection.