DNA electrochemical biosensor for the detection of short DNA sequences related to the hepatitis B virus

Nucleic acid hybridization forms the basis for the diagnosis of genetic and infectious diseases. Electrochemical biosensors, coupling the inherent spe cificity of DNA recognition reactions with the high sensitivity of physical transducers, thus hold great promise for sequence-specific detection. An e lectrochemical biosensor for the voltammetric detection of DNA sequences re lated to the hepatitis B virus (HBV) is described. Synthetic single-strande d oligonucleotides ("probe") have been immobilized onto carbon paste electr odes with the adsorption at a controlled potential. The probes were hybridi zed with different concentrations of complementary ('target') sequences. Th e formed hybrids on the electrode surface were evaluated by differential pu lse voltammetry using cobalt phenanthroline, [Co(phen)(3)(3+)] as the indic ator of hybridization reaction.