Quantitative evaluation of surface topographical changes of Au thin films under DNA immobilization

A quantitative evaluation, by atomic force microscopy measurements, of the nano-topography of single and double stranded DNA functionalized Au surfaces is carried out. The two-dimensional fractal dimension was quantified for the Au surface in 0.9±0.1 and 2.1±0.3 from 1x1 μm2 and 5x5 μm2 scans respectively. It was quantified in 2.1±0.1 and in 2.4±0.3 for the Au surface after immobilization of single-stranded DNA film and in 2.0±0.1 and 1.9±0.3 for the Au surface after hybridization, from 1x1 μm2 and 5x5 μm2 scans respectively. These results indicate a topographical conforming effect of the DNA films towards a two-dimensional gaussian surface.