A novel electrochemical approach for nuclear factor kappa B detection based on triplex DNA and gold nanoparticles

The transcription factor nuclear factor kappa B (NF-kappa B) is always a standard for inducible transcription factors, while nearly all NF-kappa B studies require the measurement of the level of activated NF-kappa B in cells. Herein we report a novel electrochemical approach for accurate detection of NF-kappa B with the help of triplex DNA and gold nanoparticles (AuNPs). Firstly, double-stranded DNA (dsDNA) molecules are self-assembled on the surface of a gold electrode. Then, AuNPs are functionalized with triplex-forming oligonucleotide (TFO). Since TFO may act with the dsDNA to form triplex DNA, the TFO functionalized on the AuNPs surfaces will bind with the dsDNA immobilized on the electrode surface, bringing large amounts of electrochemical compounds [Ru(NH3)(6)](3+) close to the electrode to generate an intense electrochemical signal. However, in the presence of NF-kappa B, the protein will capture and bind with the dsDNA to replace TFO-AuNPs, resulting in significant decrease of electrochemical signal of [Ru(NH3)(6)](3+). By using this on-off strategy, NF-kappa B has been quantified in the range from 0.4 to 12.0 nM, with a detection limit of 0.13 nM. This approach has also been successfully used to detect NF-kappa B in contaminated samples with high specificity. (C) 2011 Elsevier Ltd. All rights reserved.