Self-assembled DNA networks and their electrical conductivity

We report direct measurements of the intrinsic electrical characteristics of polynucleotides using a conducting-probe atomic-force microscope under vacuum. $\mathrm{Poly}\mathrm{(dA)\cdot }\mathrm{poly}\mathrm{(dT)}$ self-assemble a cross-interlaced network on mica, but $\mathrm{poly}\mathrm{(dG)\cdot }\mathrm{poly}\mathrm{(dC)}$ self-organize a uniform two-dimensional reticulated structure. Transport studies demonstrate that $\mathrm{poly}\mathrm{(dG)\cdot }\mathrm{poly}\mathrm{(dC)}$ can act as a semiconducting nanowire and show a better conductance than that in $\mathrm{poly}\mathrm{(dA)\cdot }\mathrm{poly}\mathrm{(dT).}$