Credit: © 2009 AAAS

Nanoparticles of a material can show optical, magnetic and electronic properties that are unattainable in their bulk form. By organizing such nanoparticles into precise and adjustable assemblies, the interactions between the nanoparticles, as well as with other molecular species, could be carefully controlled, potentially leading to new properties and applications. Now, Yan Liu, Hao Yan and colleagues1 at Arizona State University and the Scripps Research Institute have created complex three-dimensional architectures of gold nanoparticles using DNA-based self-assembly.

DNA has recently emerged as one of the most versatile molecular-scale building blocks, because it can be used to form tiles with 'sticky ends' capable of binding other tiles and directing the formation of a design. Through such means, two- and three-dimensional DNA nanostructures have been created, including nanotubes. Liu, Yan and co-workers have extended this work by attaching gold nanoparticles to single-stranded DNA to form tubules in a range of designs from stacked rings to spirals.

Using electron tomography, the researchers were able to identify the three-dimensional conformations of the nanotubes, showing, for example, a left-handed chirality in the spiral tubes. Furthermore, the nanoparticles were found to be active components in the assembly process, influencing the conformation of the nanotube through steric effects.

The researchers suggest that further developments in the design of DNA tiles may allow different sizes and types of nanoparticles to be accurately placed on the inside or outside of the tubes, leading to the development of advanced nanoscale devices.