Cheng Wenlong, Campolongo Michael J, Cha Judy J, Tan Shawn J, Umbach Christopher C, Muller David A, Luo Dan
Department of Biological & Environmental Engineering, Cornell University, 226 Riley Robb, Ithaca, New York 14853, USA.
Nat Mater. 2009 Jun;8(6):519-25. doi: 10.1038/nmat2440. Epub 2009 May 3.
Free-standing nanoparticle superlattices (suspended highly ordered nanoparticle arrays) are ideal for designing metamaterials and nanodevices free of substrate-induced electromagnetic interference. Here, we report on the first DNA-based route towards monolayered free-standing nanoparticle superlattices. In an unconventional way, DNA was used as a 'dry ligand' in a microhole-confined, drying-mediated self-assembly process. Without the requirement of specific Watson-Crick base-pairing, we obtained discrete, free-standing superlattice sheets in which both structure (inter-particle spacings) and functional properties (plasmonic and mechanical) can be rationally controlled by adjusting DNA length. In particular, the edge-to-edge inter-particle spacing for monolayered superlattice sheets can be tuned up to 20 nm, which is a much wider range than has been achieved with alkyl molecular ligands. Our method opens a simple yet efficient avenue towards the assembly of artificial nanoparticle solids in their ultimate thickness limit--a promising step that may enable the integration of free-standing superlattices into solid-state nanodevices.
独立式纳米颗粒超晶格（悬浮的高度有序纳米颗粒阵列）对于设计不受衬底诱导电磁干扰的超材料和纳米器件而言是理想的。在此，我们报道了第一条基于DNA的通往单层独立式纳米颗粒超晶格的途径。以一种非常规方式，DNA在微孔受限、干燥介导的自组装过程中被用作“干性配体”。无需特定的沃森-克里克碱基配对，我们获得了离散的、独立式超晶格薄片，其中结构（颗粒间间距）和功能特性（等离子体和机械特性）均可通过调节DNA长度进行合理控制。特别地，单层超晶格薄片的颗粒间边缘到边缘间距可调节至20纳米，这一范围比使用烷基分子配体所能达到的范围宽得多。我们的方法为在其极限厚度限制下组装人工纳米颗粒固体开辟了一条简单而高效的途径——这是迈向将独立式超晶格集成到固态纳米器件中的有前景的一步。
