Prescribing Silver Chirality with DNA Origami.

Metal nanostructures of chiral geometry interacting with light via surface plasmon resonances can produce tailorable optical activity with their structural alterations. However, bottom-up fabrication of arbitrary chiral metal nanostructures with precise size and morphology remains a synthetic challenge. Here we develop a DNA origami-enabled aqueous solution metallization strategy to prescribe the chirality of silver nanostructures in three dimensions. We find that diamine silver(I) complexes coordinate with the bases of prescribed single-stranded protruding clustered DNA (pcDNA) on DNA origami via synergetic interactions including coordination, hydrogen bonds, and ion-π interaction, which induce site-specific pcDNA condensation and local enrichment of silver precursors that lowers the activation energy for nucleation. Using tubular DNA origami-based metallization, we obtain helical silver patterns up to a micrometer in length with well-defined chirality and pitches. We further demonstrate tailorable plasmonic optical activity of metallized chiral silver nanostructures. This method opens new pathways to synthesize programmable inorganic materials with arbitrary morphology and chirality.

Automated design of 3D DNA origami with non-rasterized 2D curvature.

Improving the precision and function of encapsulating three-dimensional (3D) DNA nanostructures via curved geometries could have transformative impacts on areas such as molecular transport, drug delivery, and nanofabrication. However, the addition of non-rasterized curvature escalates design complexity without algorithmic regularity, and these challenges have limited the ad hoc development and usage of previously unknown shapes. In this work, we develop and automate the application of a set of previously unknown design principles that now includes a multilayer design for closed and curved DNA nanostructures to resolve past obstacles in shape selection, yield, mechanical rigidity, and accessibility. We design, analyze, and experimentally demonstrate a set of diverse 3D curved nanoarchitectures, showing planar asymmetry and examining partial multilayer designs. Our automated design tool implements a combined algorithmic and numerical approximation strategy for scaffold routing and crossover placement, which may enable wider applications of general DNA nanostructure design for nonregular or oblique shapes.

A covalently linked dimer of [Ag25(DMBT)18].

We report the first example of a covalently bound dimer of monolayer protected atomically precise silver nanocluster [Ag25(DMBT)18]- (DMBT stands for 2,4-dimethylbenzenethiol). Covalently linked dimers could be important to design new cluster assembled materials with composite properties.