DNA to Found New Generation of Logic Chips

According to engineers at Duke University, DNA is the material of tomorrow. This is especially true when it comes to producing vast amounts of simple logic circuits. The team here says that a single graduate student could theoretically use a lab bench to produce as much of this logic circuit in a single day than all the factories around the world produce in a month. This theoretical achievement is only possible through the use of DNA, the building block of life, the group says. These nucleic acid strands can successfully replace the silicon chips that generally act as substrates for logic circuits.

Duke Pratt School of Engineering assistant professor of electrical and computer engineering Chris Dwyer says that the secret lies with using chromophores, which are basically molecules that get excited in the presence of light. He adds that the mixture he and his group are proposing as a substrate for future electronics consists of customized snippets of DNA, which are added in a solution with a bunch of other molecules. The result is a collection of billions of tiny, identical, waffle-looking structures, which are perfectly capable of self-assembly. If chromophores are added to the mix, then the nanostructures will begin to respond to light.

The same type of response is what underlines logic gates, or switches. “When light is shined on the chromophores, they absorb it, exciting the electrons. 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. This is the first demonstration of such an active and rapid processing and sensing capacity at the molecular level,” the scientist explains. In essence, he adds, light is used to replace electrical current, and DNA-based switches replace conventional circuits. The goal is the same, but the means differ considerably.

Details of the work are presented in a paper published in the latest online issue of the respected scientific journal Small. “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. [The production process is] like taking pieces of a puzzle, throwing them in a box and as you shake the box, the pieces gradually find their neighbors to form the puzzle. What we did was to take billions of these puzzle pieces, throwing them together, to form billions of copies of the same puzzle,” Dwyer says.