Determination of Integrity, Stability and Density of the DNA Layers Immobilised at Glassy Carbon and Gold Electrodes Using Ferrocyanide

The technique chosen to immobilise DNA onto electrodes can determine the density and stability of the resultant immobilised layer. DNA-modified electrodes were prepared using four common DNA immobilisation methods and characterised using ferrocyanide. The negatively charged DNA strands should repel ferrocyanide anions. The DNA layers created using adsorption at glassy carbon electrodes were unstable, while those created through chemisorption of thiol-modified DNA onto gold electrodes were repeatable and stable, and returned, on average, 94 % repulsion of the probe. The presented results show how the immobilisation protocol, and DNA type, affects the stability, repeatability, and integrity of resultant DNA layers.