Detection of DNA hybridization using electrochemical impedance spectroscopy and surface enhanced Raman scattering

The formation of double-stranded DNA (dsDNA) at gold electrodes decorated with a monolayer of gold nanoparticles bound through a self-assembled dithiol monolayer is detected via specific intercalation of proflavine. Hybridization as well as sequential built-up of the electrode architecture is monitored using Faradaic electrochemical impedance spectroscopy (EIS) as well as surface enhanced Raman scattering (SERS). The adsorption of secondary gold nanoparticles allow for amplified detection of the dsDNA integrated intercalator in a vertical gap mode configuration. The experimental design thus allows probing presence of the intercalator inside the dsDNA.

► Elucidation of intercalation process into dsDNA by means of SERS and EIS.
► A vertical gap mode of SERS is proposed to obtain SERS amplification in large distance.
► The vertical gap mode is specific for dsDNA intercalated proflavine.
► Detection of DNA hybridization by a label-free approach avoiding modification of the target DNA.