Wrinkle-Assisted Capillary Bridging for the Directed Assembly of Single-Level DNA Nanowire Arrays

Abstract

Assembly of molecular-scale nanowire arrays with defined spacing in an inexpensive and time-efficient manner enables the development of versatile functional nanodevices that are unattainable with conventional approaches involving top-down patterning techniques. This paper introduces a bottom-up method for rapidly assembling DNA molecules into periodically aligned 2-nm-thin nanowires. The method uses wettability-contrast channels composed of superhydrophilic wrinkles with a periodic high-aspect-ratio structure as the top and a hydrophobic flat surface as the bottom. After injecting the channels with DNA solution, one end of the wrinkled top is detached to facilitate unidirectional receding of an array of submicrometer-scale capillary bridges developed in between. The molecules confined in each capillary bridge are then made to evaporatively assemble into a linear structure on the flat surface, thus yielding an array of molecular-scale nanowires. The inter-nanowire separation can be controlled by tuning the wrinkle dimensions. The wrinkle-assisted capillary-bridging method, termed WaCaB, exploits the surface instability of a film-substrate system for wrinkle fabrication and employs a simple detachment process, thus offering a general and flexible pathway for the facile assembly of spatially organized single-level DNA nanowires, which can create new fabrication opportunities for devices in nanoelectronics, photonics, and biology.