title: Au nanorod helical superstructures with designed chirality.
abstract: 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.
authors.affiliation: 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.
authors.forename: Xiang
authors.initials: X
authors.lastname: Lan
authors.forename: Xuxing
authors.initials: X
authors.lastname: Lu
authors.forename: Chenqi
authors.initials: C
authors.lastname: Shen
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Ke
authors.forename: Weihai
authors.initials: W
authors.lastname: Ni
authors.forename: Qiangbin
authors.initials: Q
authors.lastname: Wang
mesh_terms: D004247:DNA / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D015394:Molecular Structure; D043942:Nanotubes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D006046:Gold; D004247:DNA