A sequence-specific DNA sensor for Hepatitis B virus diagnostics based on the host-guest recognition

In this work, we demonstrate the applicability of an electrochemical supramolecular platform to detect Hepatitis B virus (HBV) sequences. A DNA molecular beacon was designed as the probe, and immobilized onto the electrodes through the biotin at the 3′-end, while the 5′-end of the probe was labeled with 4-(4-dimethyl aminophenylazo) benzoic acid (dabcyl). The β-cyclodextrins functionalized Au nanoparticles (Au-CDs) were employed as electrochemical signal provider. The probe DNA immobilized on the electrode kept the stem-loop configuration, which shielded dabcyl from docking with Au-CDs in solution due to the steric effect. While in the presence of the target DNA, the probe conformation was changed and a double-stranded DNA (dsDNA) molecule was formed through the hybridization. Consequently, Au-CDs were linked to dsDNA owing to the host-guest recognition between β-CD and dabcyl. Thus, the hybridization events could be sensitively transduced to electrochemical signals provided by Au nanoparticles. The designed sensor favored discrimination between the healthy and single-nucleotide polymorphisms (SNP)-containing sequences. Under optimized detection conditions, the proposed method showed high sensitivity and specificity with a detection limit of 3.00 × 10 ^-13 M for HBV DNA sequence.