UC Davis

Exploring the structural and electrical properties of DNA origami nanowires is an important endeavor for the advancement of DNA nanotechnology and DNA nanoelectronics. Highly conductive DNA origami nanowires are a desirable target for creating low-cost, self-assembled, nanoelectronic devices and circuits. In this work, the structure-dependent and moisture-dependent electrical conductance of DNA origami nanowires is systematically investigated. Silicon nitride (Si3N4) on silicon semiconductor chips with gold electrodes are used for collecting electrical conductance measurements of DNA origami nanowires, which are found to be more electrically conductive on Si3N4 substrates treated with a monolayer of hexamethyldisilazane (HMDS) (~1013 ohms) than on native Si3N4 substrates without HMDS (~1014 ohms). Atomic force microscopy (AFM) measurements of the height of DNA origami nanowires on mica and Si3N4 substrates reveal that DNA origami nanowires are ~1.6 nm taller on HMDS-treated substrates than on the untreated ones indicating that the DNA origami nanowires undergo increased structural deformation when deposited onto untreated substrates, causing a decrease in electrical conductivity. Another study indicates that the same DNA origami nanowires are more electrically conductive (~1012 ohms) in ambient/humid conditions. Finally, we demonstrate that DNA origami nanowires are more electrically conductive in aqueous conditions than under dry conditions in air. These studies highlight the importance of understanding and controlling the interface conditions and environmental factors that affect the electrical conductance of DNA origami nanowires, while also revealing the potential of DNA origami nanowires to be used as sensors and electronic devices.