Biosensor for Hepatitis B Virus DNA PCR Product and Electrochemical Study of the Interaction of Di(2,2′‐bipyridine)osmium(III) with DNA

The strategy for electrochemical detection of HBV DNA PCR product (181 bps) was designed by covalently immobilizing single‐stranded HBV DNA on preoxidized glassy carbon electrode surface. The immobilization of single stranded DNA was verified by AC impedance spectra. The following hybridization reaction on surface was evidenced by electrochemical methods using Os(bpy)₂Cl₂]⁺ as an electroactive indicator. The interactions of Os(bpy)₂Cl₂]⁺ with calf thymus single and double stranded DNA immobilized on preoxidized glassy carbon electrodes were studied. Os(bpy)₂Cl₂]⁺ could bind preferentially to the duplex DNA by intercalating to base pairs. The intrinsic binding constant of Os(bpy)₂Cl₂]⁺ with calf thymus DNA was calculated to be 1.21×10⁴ M^?1. Using Os(bpy)₂Cl₂]⁺ as an electrochemical hybridization indicator, the HBV DNA sensor has been used to detect qualitatively target HBV DNA in solution with high sensitivity and selectivity.