Enhanced electrogravimetric detection of DNA hybridization on an electrochemical quartz crystal microbalance

Electrogravimetric amplification with an intercalator Hoechst 33258 on an electrochemical quartz crystal microbalance (EQCM) has been reported for detecting DNA hybridization. The self-assembled monolayer of α-thioctic acid with carboxy group is first self-assembled on a gold film of the resonator on an EQCM. The probe molecules of ssDNA have then been immobilized onto its surface. Processes of immobilization and hybridization have been examined by a quartz crystal microbalance. When the resonator is reacted with Hoechst 33258, masses of Hoechst molecules intercalate in DNA hybrids and enhance the gravimetric signal. Both electrogravimetric and electrochemical signals of the EQCM are linear with the concentration of target DNA in the range of 10^-9 mol L^-1.