Progress in DNA‐Imaging: Doublestranded Multimers and Bases of DNA Deposited on the Basal Plane of Graphite

Scanned probe techniques, such as scanning tunneling microscopy (STM) and atomic force microscopy (AFM) should facilitate sequencing of the humane genome if they could reliably image DNA‐ strands and identify DNA’s bases. We show that we can reliably deposit and analyze by STM doublestranded multimers of DNA on graphite. To progress beyond imaging, one of the first tasks in sequencing is to identify what STM images of individual bases should look like. We report here STM images of adenine with near‐atomic resolution. Adenine was adsorbed from a liquid solution onto the basal plane of graphite, where it forms monolayer‐patches stable under proper STM imaging conditions. These adsorbed monolayers have definite order with respect to the underlying graphite plane. The STM images are consistent with molecular modeling of the adsorption of adenine onto the basal plane of graphite.