Quantitative analysis of H5N1 DNA hybridization on nanowell array electrode

A nanowell array electrode-based electrochemical quantitative system without amplification was developed and applied for the detection of H5N1 target DNA. An 18-mer probe was immobilized on a nanowell array electrode with a diameter of 500 nm, which was coated with streptavidin and a self-assembly monolayer (SAM). The surface properties of probe DNA hybridization with complementary target DNA were characterized using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The AFM image shows that the depth of nanowell was reduced from 200 nm to 15 nm due to the formation of a DNA hybridization complex on the streptavidin/SAM structure. Differences in charge transfer resistance (deltaR(ct)) in EIS upon hybridization of the probe DNA with complementary target DNA were analyzed and used for the quantitation of H5N1 DNA. This approach shows that the quantitative analysis of H5N1 DNA ranging from 1 pM to 1 microM DNA is possible on a nanowell array electrode.