Duke Professor Customizes DNA and Molecules to Form Logic Circuits

Duke's Pratt School of Engineering Assistant Professor in computer and electrical engineering Chris Dwyer has shown in his newest set of experiments that by combining customized DNA and other molecules’ snippets it is possible to generate billions of tiny, similar waffle-looking structures.

He has demonstrated that these nanostructures could self-assemble efficiently and when the mixture is added with different light sensitive molecules, the waffles depict programmable and special properties that can be tapped readily. These molecules, also called chromophores, can be excited by light for creating simple switches or logic gates. These nanostructures can be utilized as the basic blocks for building up a range of applications, from the computational to the biomedical.

Rather than traditional circuits rapidly switching between yes and no or ones and zeroes through electrical current, similar responses can be stimulated through the DNA-enabled switches faster by using light.

The well understood DNA molecule is constructed with complementary nucleotide base pairs which have an affinity with each other. It is possible to synthesize the customized DNA snippets cheaply by placing the pairs in any fashion. Dwyer utilized the analogy of a jigsaw puzzle for explaining the process that occurs during mixing of all waffle ingredients in a container.

He used the waffle puzzle having 16 pieces in the present experiments and located the chromophores on the ridges of the waffle. It is possible to construct more complex circuits by building structures made of these small components or through building larger waffles and the possibilities are numerous.

According to Dwyer, besides their usage for computing applications, these nanostructures are essentially sensors and many biomedical applications can be developed through them. Miniaturized nanostructures capable of being developed will be able to respond to various proteins that act as disease markers in one drop of blood.

According to an engineer from Duke University, in one day a single grad student working on his lab bench will be able to make more number of simple logic circuits than the total monthly output of silicon chips manufactured in the world. He thinks that these new generation logic circuits that will be incorporated in computers can be manufactured economically in nearly limitless quantities. Computer engineers would be able to leverage the special DNA properties, namely, the double-helix carrier having complete information on life, rather than silicon chips that serve as the base for electric circuits.