Electrochemical impedance spectroscopy and surface plasmon resonance studies of DNA hybridization on gold/SiOxinterfacesThe HTML version of this article has been enhanced with colour images.

The use of Au/SiOxinterfaces for the investigation of DNA hybridization using electrochemical impedance spectroscopy (EIS) and surface plasmon resonance (SPR) simultaneously is demonstrated. Standard glass chemistry was used to link single-stranded DNA (ss-DNA) on aldehyde-terminated Au/SiOxinterfaces. The layer thickness and amount of grafted oligonucleotides (ODNs) were calculated from SPR on the basis of a multilayer system of glass/Ti/Au/SiOx/grafted molecule. Capacitance and resistance values of the modified interface before and after hybridization were calculated from EIS data using an equivalent circuit and allowed the affinity rate constant, KA= 4.07 × 105M−1, to be determined. The EIS results were comparable to those obtained by SPR hybridization kinetics recorded in parallel. [ABSTRACT FROM AUTHOR]