Analytical Sciences

Label-free Electrochemical Detection of the Human Adenovirus 40/41 Fiber Gene

Min-Jung SONG* and Joon-Hyung JIN**

*Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea
**Department of Mechanical Engineering, Korea University, 1, 5-Ga, Anam-dong, Seoungbuk-gu, Seoul 136-713, Korea

A nanoporous silicon-based label-free DNA biosensor was fabricated to monitor rapidly enteric adenovirus types 40 and 41, a leading cause of viral gastroenteritis in children. Nanoporous silicon (NPS) was formed by an anodic etching process in a mixture solution containing hydrofluoric acid and ethanol. The polypyrrole (PPy) film was directly electropolymerized on The NPS substrate. Twenty-five base pairs of probe DNA (pDNA), derived from the fiber gene, was electrochemically doped on the PPy-coated NPS substrate. The conductivity change due to the immobilized pDNA and hybridized target DNA (tDNA) was expressed as an arbitrary factor, γ, which is a normalized numerical term used for the selective quantification of the tDNA. γ was inversely proportional to the concentration of complementary tDNA, but independent of the non-complementary tDNA. The sensitivity slope for detecting tDNA_c was –1.54 μM⁻¹, based on the factor γ in the range of 0.4 to 1.0 μM of tDNA. The surface roughness was characterized using atomic force microscopy.

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