Programming Nanophotonic Materials with DNA

Abstract

DNA is a unique nanoscale material that enables the design and synthesis of nanoscale structures of prescribed shape and functionality via programmable self-assembly. Angstrom-level control over the location and orientation of programmed Watson-Crick basepairs offers the ability to scaffold and spatially organize optically active materials to yield novel optical and photonic properties. Here, we present two distinct strategies for designing and synthesizing DNA-based photonic materials, and emphasize the roles of computational modeling in this process. First, we use computational modeling to design mechanically stiff nanoscale DNA “molds” that have user-specified three-dimensional cavity with a nucleating gold seed, which grows in solution to fill and replicate the cavity. We demonstrate the capability of producing nanoparticles of various shapes and materials that exhibit plasmonic properties that are consistent with electromagnetism simulations. In silico design of stiff molds of nearly arbitrary geometric cavities with resulting optical properties that are prescribed a priori enable a property-by-design framework for producing inorganic particles with prescribed functional properties. Second, we use DNA to program the scaffolding of chromophores into complex three-dimensional assemblies, enabling controlled energy transfer at the nanoscale. This strategy is inspired by nature, where cells use organized assemblies of chromophores to capture photons and funnel the resulting excitons toward the reaction center where they are converted to chemical energy. In particular, the close-packing of chromophores results in the emergence of quantum coherence that can strongly affect exciton transport across the structure. Using Forster energy transfer modeling, as well as a hybrid molecular dynamics and quantum mechanical approach, we demonstrate how emergent excitonic and light-harvesting properties of diverse DNA-dye assemblies can be elucidated.