Nature Commun. 4, 2000 (2013)

DNA is a versatile molecule that can be used to form a variety of intricate self-assembled nanostructures and devices. The molecule has, for example, been used to direct the assembly of dynamic nanoparticle structures such as dimers and superlattices that can be switched between two different states. Itamar Willner and colleagues at the Hebrew University of Jerusalem and Ohio University have now used interlocked rings of DNA to form switchable arrangements of gold nanoparticles that can modulate their spectroscopic properties.

The researchers used three-ring catenated DNA nanostructures, which can be converted into different configurations using fuel and blocker DNA strands. Switchable arrangements of nanoparticles were created by attaching two, three or four gold nanoparticles of different sizes to the catenated structures with DNA tethers. By adjusting the distance between the different gold nanoparticles, the plasmonic coupling interaction between the particles could be controlled. Similarly, by adjusting the distance between a fluorophore and a gold nanoparticle that were both attached to the DNA nanostructures, surface-enhanced fluorescence and fluorescence quenching phenomena could be detected.

Willner and colleagues suggest that their catenated DNA machines could also be used to explore the fundamental properties of assemblies of nanoparticles with various sizes and compositions.