Polarizability of G4-DNA observed by electrostatic force microscopy measurements.

G4-DNA, a quadruple helical motif of stacked guanine tetrads, is stiffer and more resistant to surface forces than double-stranded DNA (dsDNA), yet it enables self-assembly. Therefore, it is more likely to enable charge transport upon deposition on hard supports. We report clear evidence of polarizability of long G4-DNA molecules measured by electrostatic force microscopy, while coadsorbed dsDNA molecules on mica are electrically silent. This is another sign that G4-DNA is potentially better than dsDNA as a conducting molecular wire.