Electrochemical recognition of biomolecule through DNA homogenous hybridization based on host-guest recognition technique

Electrochemical DNA biosensor with high sensitivity of homogenous hybridization was fabricated on the basis of host-guest recognition between β-cyclodextrin (β-CD) and m-toluic acid (mTA). β-CD, as the host molecule, was electropolymerized on the poly(N-acetylaniline)-modified glassy carbon electrode, and mTA, was labeled on the probe DNA as the guest through acid-amine condensation reaction. Two intercalators were used as electrochemical indicators to detect DNA hybridization: methylene blue (MB) and daunorubicin (DNM). The electrochemical signals of MB were linear in the range of complementary DNA from 2.0 × 10^-12 M to 2.0 × 10 ^-10 M with a detection limit of 7.6 × 10^-13 M. The electrochemical response of DNM was linear with the concentrations of complementary from 1 × 10^-12 M to 1 × 10^-9 M with a detection limit of 6.0 × 10^-13 M. This DNA biosensing technique exhibited excellent reproducibility and stability.