DNA Double Helix

Resolution of the double helix of Lambda digest DNA. While the periodicity is clearly visible in the height image (left) it is especially striking in the phase image (right). This may be because the tip was shaped such that it fit into the helix grooves along a particular orientation, thus increasing dissipation.

Imaged on a Cypher in a NiCl₂ buffer using an Olympus BioLever Mini in AC Mode with an amplitude of 8 Å. Image size 150 x 75 nm.