The study, carried out by a team from the Department of NanoEngineering at UC San Diego, is aiming to solve the complex problem of how to place trillions of unique and functional nanostructures at precise locations in an efficient (and cheap) way. The breakthrough means that nanostructured materials could be used for fabricating a range of products, including multiplex sensors, photovoltaics, optical circuits and consumer electronics.

Through the key approach of using biomolecules, such as DNA and proteins, the team hope to engineer the orientation and placement of nanoscale materials – such as metal nanocrystals, carbon nanotubes and semi-conducting nanowires – into the desired device architectures that are reproducible in high yields and at low cost.

Published in Nature Nanotechnology (doi: 10.1038/nnano.2009.450), the study examined ways of combining the advantages of bottom-up self-assembly and top-down lithography to pattern sub-10nm components over large areas.

As Albert Hung, lead author of the paper, points out “Lithography allows for superior control over pattern design and registry, but achieving higher and higher resolutions is becoming significantly more difficult and expensive. Self-assembly offers high resolution and chemical specificity, and rationally designed DNA nanostructures proved to be a powerful tool for integrating the two strategies.” The team were able to demonstrate a complete process for true integration of top-down and bottom-up assembly, patterning sub-10nm components with registry beyond the local level.

The work could help in the construction of sensor arrays or electrical or optical devices based on nanometer-scale components, and the research team are especially concerned with the engineering of complex arrangements of nanoparticles for both sensing and plasmonic solar cell applications. They are also focusing on the ability to use such DNA arrays for patterning one-dimensional nanoelectronic materials, such as CNTs and silicon nanowires.

As team leader, Jennifer Cha, states, “We're interested in examining how selective this method is for different shapes of DNA nanostructures and also looking to pattern different components such as single proteins, different metal nanostructures and carbon nanotubes.”

Although mass production using synthetic DNA nanostructures is still some way off, there is hope that the discoveries made in the study will lead to an understanding of how this can be achieved, and the team are now examining ways of developing a device based on their research method.