Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine and i-Lab, CAS Center for Excellence in Brain Science, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences , Suzhou, 215123 China.
J Am Chem Soc. 2015 Jan 14;137(1):457-62. doi: 10.1021/ja511333q. Epub 2014 Dec 29.
A great challenge for nanotechnology is to controllably organize anisotropic nanomaterials into well-defined three-dimensional superstructures with customized properties. Here we successfully constructed anisotropic Au nanorod (AuNR) helical superstructures (helices) with tailored chirality in a programmable manner. By designing the 'X' pattern of the arrangement of DNA capturing strands (15nt) on both sides of a two-dimensional DNA origami template, AuNRs functionalized with the complementary DNA sequences were positioned on the origami and were assembled into AuNR helices with the origami intercalated between neighboring AuNRs. Left-handed (LH) and right-handed (RH) AuNR helices were conveniently accomplished by solely tuning the mirrored-symmetric 'X' patterns of capturing strands on the origami. The inter-rod distance was precisely defined as 14 nm and inter-rod angle as 45°, thus a full helix contains 9 AuNRs with its length up to about 220 nm. By changing the AuNR/origami molar ratio in the assembly system, the average number of AuNR in the helices was tuned from 2 to 4 and 9. Intense chiroptical activities arose from the longest AuNR helices with a maximum anisotropy factor of ∼0.02, which is highly comparable to the reported macroscopic AuNR assemblies. We expect that our strategy of origami templated assembly of anisotropic chiral superstructures would inspire the bottom-up fabrication of optically active nanostructures and shed light on a variety of applications, such as chiral fluids, chiral signal amplification, and fluorescence combined chiral spectroscopy.
纳米技术面临的一个巨大挑战是可控地将各向异性纳米材料组织成具有定制性质的明确定义的三维超结构。在这里，我们成功地以可编程的方式构建了具有定制手性的各向异性金纳米棒（AuNR）螺旋超结构（螺旋）。通过设计二维 DNA 折纸模板两侧 DNA 捕获链（15nt）排列的“X”图案，用互补 DNA 序列功能化的 AuNR 被定位在折纸上，并与折纸穿插在相邻的 AuNR 之间组装成 AuNR 螺旋。通过仅调整折纸捕获链的镜像对称“X”图案，方便地完成了左手（LH）和右手（RH）AuNR 螺旋。棒间距离被精确定义为 14nm，棒间角度为 45°，因此一个完整的螺旋包含 9 个 AuNR，其长度可达约 220nm。通过改变组装体系中 AuNR/折纸的摩尔比，可以从 2 到 4 和 9 来调整螺旋中 AuNR 的平均数量。最长的 AuNR 螺旋产生了强烈的手性光学活性，其各向异性因子最大约为 0.02，与报道的宏观 AuNR 组装体高度可比。我们期望折纸模板组装各向异性手性超结构的策略将激发对光活性纳米结构的自下而上制造，并为各种应用提供启示，例如手性流体、手性信号放大和荧光结合手性光谱学。
