The effect of applied potential pulses on DNA functionalization (thiolated single stranded DNA) and hybridization processes has been monitored in-situ on gold surfaces using electrochemical quartz crystal microbalance with dissipation (EQCM-D). The applied potentials were chosen with respect to the potential of zero charge (E-pzc) of the gold surfaces: a positive potential to attract the negatively charged DNA molecules and a negative potential to enhance the vertical alignment due to electrostatic repulsion. The obtained results clearly show that both DNA modification and hybridization are strongly enhanced by applying potential pulses. Based on the EQCM-D results, we present a model to explain the influence of the potential pulsing. Aside from the effect of applied potentials on DNA related processes, this work also demonstrates the versatility of the combination of electrochemistry and quartz crystal microbalance with dissipation in facilitating real-time in situ monitoring of such processes. (C) 2014 Elsevier B.V. All rights reserved
