Directional observations of guanine and cytosine pairing structures on HOPG

Abstract

Abstract The molecular self-assembly of deoxyribonucleic acid (DNA) plays an important role in understanding how nucleic acids form and can be exploited to construct nanostructures. In this study, scanning tunneling microscopy (STM) was used to observe nanostructures that form from co-adsorption of the guanine (G) and cytosine (C) complementary DNA bases on a highly oriented pyrolytic graphite surface. The high-resolution STM images show that the well-ordered co-adsorption structures are attributed to the rows formed from Watson–Crick G–C pairs, which are distinct from the structures observed for individual G–C components. The observed co-adsorption structure was modeled by density functional theory calculations, which provide information on the intermolecular interactions underlying its formation.