Self-Assembly of 3D DNA-Nanoparticle Superlattices on Patterned Surfaces

DNA-programmable assembly is a powerful approach to organize nanoscale objects into well-defined 2D and 3D lattices and translate the advances of nanoscale building blocks into mesoscale architectures. However, to integrate the lattices into devices and other material systems, the methods for their precise placements on planar substrates, as well as assembly at the pre-determined surface locations are required. We developed an approach to direct the growth of 3D DNA-nanoparticle lattices at the desired surface locations over macroscopic areas using microscale lithographic patterns. We investigated the factors affecting the growth of 3D superlattices on these patterned substrates and established a robust pattern-guided assembly method. We applied small angle x-ray scattering (SAXS), optical microscopy, scanning electron microscopy (SEM) to reveal the assembly processes and the structure of the resulting lattices. The established approach provides a new material fabrication platform that combines nanoscale control of 3D lattices, as provided by DNA-programmable assembly, with mesoscale and macroscale control of self-assembled materials, as enabled by patterning. The developed method also allows for a systematic investigation of the nucleation and growth of DNA-guided assemblies at the interfaces. The established approach opens a possibility for integration of 3D nanoparticle lattices into devices for precisely positioning assemblies on substrates.