DNA has formed the backbone of self-assembling logic circuits designed by a team at Duke University. To communicate, the circuits employ light-emitting molecules already widely used by biologists in their own experiments.
Chris Dwyer, assistant professor of electrical and computer engineering at Duke’s Pratt School of Engineering, said the technique could be used to build intelligent but tiny biosensors as well as nanoscale encryption keys.
Dwyer said the logic is form of diode-diode logic, one of the earliest approaches to digital computation used in electronics. Although it cannot form all the possible Boolean logic gates, it can be used to build simple computers from AND and OR gates. In the Duke University scheme, the diodes of an electronic circuit are replaced with chromophores - light-absorbing elements - attached to segments of DNA.
DNA-linked chromophores, particularly those that fluoresce, are used widely in biological experiments as they make it easy to identify the locations of genetic elements within a cell. Theodor Förster found in 1948 that chromophores can pass energy to other, different chromophores close by through a coupling process. Biologists often use this in Förster or fluorescence resonance energy transfer (FRET) to show when molecules such as proteins are coupled together in complexes.