IBM experimenting with DNA to build chips
Will the building block of life become the building block of the semiconductor industry? It’s possible.Scientists at IBM are conducting research into arranging carbon nanotubes–strands of carbon atoms that can conduct electricity–into arrays with DNA molecules. Once the nanotube array is meticulously constructed, the laboratory-generated DNA molecules could be removed, leaving an orderly grid of nanotubes. The nanotube grid, conceivably, could function as a data storage device or perform calculations.
“These are DNA nanostructures that are self-assembled into discrete shapes. Our goal is to use these structures as bread boards on which to assemble carbon nanotubes, silicon nanowires, quantum dots,” said Greg Wallraff, an IBM scientist and a lithography and materials expert working on the project. “What we are really making are tiny DNA circuit boards that will be used to assemble other components.”
The work, which builds on the groundbreaking research on “DNA origami” conducted by California Institute of Technology’s Paul Rothemund, is only in the preliminary stages. Nonetheless, a growing number of researchers believe that designer DNA could become the vehicle for turning the long-touted dream of “self-assembly” into reality.
Chips made on these procedures could also be quite small. Potentially, DNA could address, or recognize, features as small as two nanometers. Cutting-edge chips today have features that average 45 nanometers. (A nanometer is a billionth of a meter.)
“There is nothing else out there that we can do that with,” said Jennifer Cha, an IBM biochemist working on getting the biological and nonbiological molecules to interact.
Right now, products get manufactured in a top-down approach with machinery and equipment manipulating raw materials. In self-assembly, the intrinsic chemical and physical properties of molecules, along with environmental factors, coax the raw materials into complex structures. It works with snowflakes, after all.
Getting the raw materials to behave in a precise, orderly manner, however, remains a challenge, which is where DNA comes in. DNA consists of specific chemical bases (guanine, cytosine) that bind and react in somewhat predictable ways with each other.
“The sequence (of base pairs in DNA) is well known,” said Cha. “Most people are acknowledging that DNA and these biological scaffolds are actually quite useful to at least pattern very small systems.”
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