Logic chips built from DNA

Posted by Staff writer

A Duke University engineer says he can produce more simple logic circuits in a day than the world's entire monthly output of silicon chips.

Chris Dwyer, assistant professor of electrical and computer engineering at Duke, mixed customized snippets of DNA and other molecules including light-sensitive molecules known as chromophores.

DNA is made up of pairs of complimentary nucleotide bases that have an affinity for each other, and customized snippets of DNA can be synthesized cheaply by putting the pairs in any order.

DNA's natural ability to latch onto corresponding and specific areas of other DNA snippets means the molecules self-assemble to create billions of identical, tiny, waffle-looking structures.

When light excites the chromophores, simple logic gates, or switches, are created, working much faster than conventional switches.

"When light is shined on the chromophores, they absorb it, exciting the electrons," Dwyer said. "The energy released passes to a different type of chromophore nearby that absorbs the energy and then emits light of a different wavelength. That difference means this output light can be easily differentiated from the input light, using a detector."

Dwyer said the experiment was the first demonstration of such an active and rapid processing and sensing capacity at the molecular level.

"Conventional technology has reached its physical limits. The ability to cheaply produce virtually unlimited supplies of these tiny circuits seems to me to be the next logical step," he said.