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Engineering of material showing precisely tailored optical response in the visible range remains challenging since it is still extremely demanding to shape materials with nanometer precision using conventional top-down lithography. Approaches based on lithography are also inherently difficult to scale up and only in a limited way extendable to three dimensions. DNA origami, in contrast, offers the possibility to excel these limitations. For DNA origami1,2,3 hundreds of rationally designed "staple" oligonucleotides are hybridized to a long single-stranded DNA scaffold strand, which forces it to assume a specific three-dimensional shape. The resulting objects are fully addressable by their DNA sequence. This property can be utilized to decorate DNA origami structures with nanocomponents in a unique, sequence-specific manner. With DNA origami we arranged plasmonic nanoparticles into nanoscale helices. We produced complex bulk material from precisely assembled nanostructures that possess tailored optical activity in the visible range. As a collective optical response emerging from our nanostructures in solution, we detect pronounced circular dichroism originating from the plasmon-plasmon interactions in the nanoparticle helices. The observed effect is isotropic and by design switchable between left- and right-handed orientation4.
[1] N. C. Seeman. J. theor. Biol. 99, 237 (1982). [2] P. W. K. Rothemund. Nature 440, 297, (2006). [3] S. M. Douglas et al. Nature 459, 414 (2009). [4] A. Kuzyk et al. Nature 483, 311 (2012). |
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