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Chiral plasmonic DNA nanostructures with switchable circular dichroism
Robert Schreiber, Ngoc Luong, Zhiyuan Fan, Anton Kuzyk, Philipp C. Nickels, Tao Zhang, David M. Smith, Bernard Yurke†,‡, Wan Kuang*,‡, Alexander O. Govorov & Tim Liedl

Department of Materials Science and Engineering, Department of Electrical & Computer Engineering, §Department of Chemistry and Biochemistry

Boise State University, Boise, Idaho 83725, United States.

Circular dichroism spectra of naturally occurring molecules and also of synthetic chiral arrangements of plasmonic particles often exhibit characteristic bisignate shapes. Such spectra consist of peaks next to dips (or vice versa) and result from the superposition of signals originating from many individual chiral objects oriented randomly in solution. Here we show that by first aligning and then toggling the orientation of DNA-origami-scaffolded nanoparticle helices attached to a substrate, we are able to reversibly switch the optical response between two distinct circular dichroism spectra corresponding to either perpendicular or parallel helix orientation with respect to the light beam. The observed directional circular dichroism of our switchable plasmonic material is in good agreement with predictions based on dipole approximation theory. Such dynamic metamaterials introduce functionality into soft matter-based optical devices and may enable novel data storage schemes or signal modulators.

KEYWORDS: Self-Assembly, DNA nanotechnology, DNA origami, plasmonics, electron microscopy

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Recent News

Boise State Featured in Bruker Newsletter

The project at Boise State was led by Dr. Elton Graugnard, who is an assistant professor in the Department of Materials Science and Engineering (MSE). The Boise State “B” DNA origami project was conceived to help students learn how to produce DNA origami nanostructures.

“The students need something to get started with, so we thought this would be a fun way for them to learn,” said Graugnard. “The logo synthesis was really a training exercise in this technique of DNA origami. You use DNA as a programmable sort of breadboard for organizing nanoparticles at a scale that is difficult to achieve with other techniques. If you can make something that looks like a “B” it demonstrates that you can make arbitrary shapes.”

b-scan-in-progress

Full article from Bruker

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Team Led by Will Hughes Wins Grant to Research DNA for Next-gen Memory Devices

Molecular circuits still have a long way to go before they are used in commercial products, but semiconductor companies like Micron Technology currently are looking at ways to make new computer chips using the programmable nature of DNA. A research team at Boise State led by associate MSE professor Will Hughes was recently awarded a $1.5 million grant from the National Science Foundation to develop the knowledge necessary to make manufacturing with DNA a reality.

Hughes’ team also includes Wan Kuang, associate professor in the Department of Electrical and Computer Engineering; Eric Lindquist, director of the Public Policy Center; Peng Yin at Harvard University’s prestigious Wyss Institute; and Scott Sills at Micron Technology. The goal for the team is to address the technical and non-technical barriers to implementing scalable nano-manufacturing, from DNA crystallization to semiconductor fabrication in Idaho.

NSF Grant Details

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Enhanced Dna Sensing via Catalytic Aggregation of Gold Nanoparticles



Herbert M. Huttanus, Elton Graugnard, Bernard Yurke,†,‡ William B. Knowlton,†,‡ Wan Kuang, William L. Hughes, Jeunghoon Lee,*,§

Department of Materials Science and Engineering, Department of Electrical & Computer Engineering,

§Department of Chemistry and Biochemistry

Boise State University, Boise, Idaho 83725, United States.

A catalytic colorimetric detection scheme that incorporates a DNA-based hybridization chain reaction into gold nanoparticles

was designed and tested. While direct aggregation forms an inter-particle linkage from only one target DNA strand, catalytic aggregation forms multiple linkages from a single target DNA strand. Gold nanoparticles were functionalized with thiol-modified DNA strands capable of undergoing hybridization chain reactions. The changes in their absorption spectra were measured at different times and target concentrations and compared against direct aggregation. Catalytic aggregation showed a multifold increase in sensitivity at low target concentrations when compared to direct aggregation. Gel electrophoresis was performed to compare DNA hybridization reactions in catalytic and direct aggregation schemes, and the product formation was confirmed in the catalytic aggregation scheme at low levels of target concentrations. The catalytic aggregation scheme also showed high target specificity. This application of a DNA reaction network to gold nanoparticle-based colorimetric detection enables highly-sensitive, field-deployable, colorimetric readout systems capable of detecting a variety of biomolecules.

KEYWORDS: DNA, Nanoparticle, Catalytic aggregation, Colorimetric detection, Hybridization chain reaction

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Multiscaffold DNA Origami Nanoparticle Waveguides

William P. Klein, Charles N. Schmidt, Blake Rapp, Sadao Takabayashi, William B. Knowlton,†,‡ Jeunghoon Lee,§ Bernard Yurke,†,‡ William L. Hughes, Elton Graugnard, Wan Kuang,*,‡

Department of Materials Science and Engineering, Department of Electrical & Computer Engineering,

§Department of Chemistry and Biochemistry

Boise State University, Boise, Idaho 83725, United States.

DNA origami templated self-assembly has shown its potential in creating rationally designed nanophotonic devices in a parallel and repeatable manner. In this investigation, we employ a multiscaffold DNA origami approach to fabricate linear waveguides of 10 nm diameter gold nanoparticles. This approach provides independent control over nanoparticle separation and spatial arrangement. The waveguides were characterized using atomic force microscopy and far-field polarization spectroscopy. This work provides a path toward large-scale plasmonic circuitry.

KEYWORDS: Self-Assembly, DNA nanotechnology, DNA origami, plasmonics, darkfield microscopy, atomic force microscopy

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Boise State Logo Synthesized from DNA

As part of an effort aimed at controlling matter at the nanoscale, BSU researchers have created a molecule-sized Boise State logo using DNA. The team, led by Elton Graugnard, programmed a long loop of single-stranded DNA to “fold” into the shape of the B logo using 170 short, complementary DNA “staples”. Roughly one trillion identical logos were produced in 4 hours. The synthesis was verified with a Bruker MultiMode 8 atomic force microscope. The results demonstrate the ability to program DNA to form arbitrary shapes with extreme precision. Such DNA structures are being developed in Boise State’s Nanoscale Materials and Device Group as novel materials for building future electronic and optical computer circuits from molecules.

Although molecular circuits still have a long way to go before they are used in commercial products, semiconductor companies like Micron Technology are currently looking at ways to make new computer chips using the programmable nature of DNA. In a related effort, a research team at Boise State led by Will Hughes, Associate Professor in MSE, was recently awarded a $1.5M grant from the National Science Foundation to develop the knowledge necessary to make manufacturing with DNA a reality.

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