Electrochemical Detection of DNA Hybridization Using Biometallization

• Published in: Analytical chemistry (Washington) Vol. 77; no. 2; pp. 579 - 584
• Main Authors: Hwang, Seongpil, Kim, Eunkyung, Kwak, Juhyoun
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.01.2005
• Subjects: Alkaline Phosphatase - metabolism; Analytical chemistry; Biotinylation; Chemistry; DNA - chemistry; DNA Probes - analysis; Electrochemical methods; Electrochemistry - methods; Enzymes, Immobilized; Exact sciences and technology; Nucleic Acid Hybridization - methods; Silver - chemistry; Surface Plasmon Resonance; Phosphates; Alkaline phosphatase; Gold; Enzyme; Electrochemical method; Anodic stripping voltammetry; Phosphoric monoester hydrolases; Metal ion; Metallizing; Esterases; Biotin; Metal; Oligomer; Reducing agent; Silver; Enzymatic method; DNA; Hydrolases; Oligonucleotide; DNA hybridization
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac048778g

We demonstrate the amplified detection of a target DNA based on the enzymatic deposition of silver. In this method, the target DNA and a biotinylated detection DNA probe hybridize to a capture DNA probe tethered onto a gold electrode. Neutravidin-conjugated alkaline phosphatase binds to the biotin of the detection probe on the electrode surface and converts the nonelectroactive substrate of the enzyme, p-aminophenyl phosphate, into the reducing agent, p-aminophenol. The latter, in turn, reduces metal ions in solutions leading to deposition of the metal onto the electrode surface and DNA backbone. This process, which we term biometallization, leads to a great enhancement in signal due to the accumulation of metallic silver by a catalytically generated enzyme product and, thus, the electrochemical amplification of a biochemically amplified signal. The anodic stripping current of enzymatically deposited silver provides a measure of the extent of hybridization of the target oligomers. This biometallization process is highly sensitive, detecting as little as 100 aM (10 zmol) of DNA. We also successfully applied this method to the sequence-selective discrimination between perfectly matched and mismatched target oligonucleotides including a single-base mismatched target.