Zhang Wei, Jiang Chuan, Guo Xin, Muhammad Faran Ashraf Baig Mirza, Ni Caihong, Xiao Shou-Jun
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China; Current address : Bruker (Beijing) Scientific Technology Co. Ltd, China.
J Colloid Interface Sci. 2022 Jun 15;616:499-508. doi: 10.1016/j.jcis.2022.02.038. Epub 2022 Feb 12.
Formation of coupled double crossovers (DXs) in a circular 106-mer oligonucleotide (c106nt) could generate stable tiles with the tile core span of 10 half turns. The large-span tiles with complicated curvatures and mechanics could assemble 2D lattices under different environments. Hence, 2D DNA lattice structures based on tile types and sequences, tile packing modes of corrugation and non-corrugation, and assembly media of solution and the substrate-solution interface are yet to be explored.
Two c106nt scaffold strands with different sequences were synthesized. Four types of tiles, two rectilinear and two triangular tiles, were designed and their 2D assemblies were examined by atomic force microscopy (AFM).
The DX-coupled tiles provided fair strength and rigidity to assemble 2D lattices. Due to the complicated curvature and mechanics of tiles, the two-tile assemblies in solution displayed a few ripe lattices of ribbons, tubes, or polycrystalline aggregates as the minor products and tile oligomers as the major products; whereas the one-tile assemblies via substrate mediation exhibited well-organized monolayer lattices covering the whole mica disk. The herringbone packing patterns were first observed in DNA nanostructures. Based on the lattice constants and the surface coverages of lattices, we estimated the lattice yields for the substrate-mediated assemblies.
在环状106聚体寡核苷酸（c106nt）中形成耦合双交换（DXs）可生成具有10个半圈的瓦片核心跨度的稳定瓦片。具有复杂曲率和力学性质的大跨度瓦片能够在不同环境下组装二维晶格。因此，基于瓦片类型和序列、波纹状和非波纹状瓦片堆积模式以及溶液和底物 - 溶液界面等组装介质的二维DNA晶格结构仍有待探索。
合成了两条具有不同序列的c106nt支架链。设计了四种类型的瓦片，包括两种直线形和两种三角形瓦片，并通过原子力显微镜（AFM）检查它们的二维组装情况。
DX耦合瓦片为组装二维晶格提供了相当的强度和刚性。由于瓦片具有复杂的曲率和力学性质，溶液中的双瓦片组装以少数成熟的带状、管状或多晶聚集体晶格作为次要产物，而以瓦片寡聚物作为主要产物；而通过底物介导的单瓦片组装则呈现出覆盖整个云母盘的组织良好的单层晶格。在DNA纳米结构中首次观察到了人字形堆积模式。基于晶格常数和晶格的表面覆盖率，我们估算了底物介导组装的晶格产率。
