Nanoscience “Goes Big”

Scientists have created a multitude of nano scale materials, such as metal nanocrystals, carbon nanotubes and semiconducting nanowires. However, despite their appeal, it has remained an astounding challenge to engineer the orientation and placement of these materials into the desired device architectures that are reproducible in high yields and at low costs. Jen Cha, a UC San Diego nanoengineering professor, and her team of researchers, have discovered that one way to bridge this gap is to use biomolecules, such as DNA and proteins.

“Self-assembled structures are often too small and affordable lithographic patterns are too large,” said lead author Albert Hung. “But rationally designed synthetic DNA nanostructures allow us to access length scales between five and 100 nanometers and bridge the two systems.” Hung said the recently discovered method may be useful for fabricating nanoscale electronic or optical circuits and multiplex sensors.

One of the main applications of this research that Cha and her group are interested in is for sensing. “There is no foreseeable route to be able to build a complex array of different nanoscale sensing elements currently,” said Cha. “Our work is one of the first clear examples of how you can merge top down lithography with bottom up self assembly to build such an array. That means that you have a substrate that is patterned by conventional lithography, and then you need to take that pattern and merge it with something that can direct the assembly of even smaller objects, such as those having dimensions between two and 20 nanometers. You need an intermediate template, which is the DNA origami, which has the ability to bind to something else much smaller and direct their assembly into the desired configuration. This means we can potentially build transistors from carbon nanotubes and also possibly use nanostructures to detect certain proteins in solutions. Scientists have been talking about patterning different sets of proteins on a substrate and now we have the ability to do that.” Cha said the next step would be to actually develop a device based on this research method.; Source: University of California - San Diego