|Jen Cha, a UC San Diego nanoengineering professor, is pushing the envelop in nanoscience by using biology to engineer the assembly of nanoscale materials for applications in medicine, electronics and energy.|
San Diego, CA, January 7, 2010 -- Nanoscience has the potential to play an enormous role in enhancing a range of products, including sensors, photovoltaics and consumer electronics. Scientists in this field 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 – until now. 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. Details of this discovery were recently published in a paper titled “Large Area Spatially Ordered Arrays of Gold Nanoparticles Directed by Lithographically Confined DNA Origami,” in Nature Nanotechology.
“Self-assembled structures are often too small and affordable lithographic patterns are too large,” said Albert Hung, lead author of the Nature Nanotechnology paper and a post doc working in Cha’s lab. “But rationally designed synthetic DNA nanostructures allow us to access length scales between 5 and 100 nanometers and bridge the two systems.
“People have created a huge variety of unique and functional nanostructures, but for some intended applications they are worthless unless you can place individual structures, billions or trillions of them at the same time, at precise locations,” Hung added. “We hope that our research brings us a step closer to solving this very difficult problem.”
Hung said the recently discovered method may be useful for fabricating nanoscale electronic or optical circuits and multiplex sensors. “A number of groups have worked on parts of this research problem before, but to our knowledge, we're the first to attempt to address so many parts together as a whole,” he said.
|Albert Hung, a UCSD nanoengineering post doc, aided in a recent discovery that could lead to enhanced sensors and electronics using nano materials.|
Cha said the next step would be to actually develop a device based on this research method. “I’m very interested in the applications of this research and we’re working our way to get there,” she said.
For the last 6 years, Cha’s research has focused on using biology to engineer the assembly of nanoscale materials for applications in medicine, electronics and energy. One of the limitations of nanoscience is it doesn’t allow mass production of products, but Cha’s work is focused on trying figure out how to do that and do it cheaply. Much of her recent work has focused on using DNA to build 2D structures.
“Using DNA to assemble materials is an area that many people are excited about,” Cha said. “You can fold DNA into anything you want – for example, you can build a large scaffold and within that you could assemble very small objects such as nano particles, nano wires or proteins.
“Engineers need to understand the physical forces needed to build functional arrays from functional materials,” she added. “My job as a nanoengineer is to figure out what you need to do to put all the different parts together, whether it’s a drug delivery vehicle, photovoltaic applications, sensors or transistors. We need to think about ways to take all the nano materials and engineer them it into something people can use and hold.”
The schematic illustrates the three key steps: (i) high-yield origami and nanocrystal binding, (ii) controlled DNA origami adsorption and (iii) drying and salt removal.
"Large-area spatially ordered arrays of gold nanoparticles directed by lithographically confined DNA origami," Nature Nanotechnology. Albert M. Hung, Christine M. Micheel, Luisa D. Bozano, Lucas W. Osterbur, Greg M. Wallraff, and Jennifer N. Cha.
Jacobs School of Engineering