Stanford scientists are using the backbones of DNA and specialty fluorescent molecules to detect organic compounds in vapor. The technique relies on replacing traditional DNA nucleobases with one of seven fluorescent molecules developed at Stanford. These new nucleobases change color in the presence of certain organic compounds, providing an indication of what this new nose is ‘smelling’.
Florent Samain, a postdoctoral researcher in chemistry and lead author on the Angewandte Chemie paper, used DNA synthesis techniques to generate a library of all 2,401 possible ways that the seven substitute molecules could be combined in a string of four units.
The team then screened all the possible combinations for sensitivity to four different test substances – as vapors – that differed significantly in their structural and electronic properties.
One substance was commonly used as an aquatic herbicide, another as a solvent in research and industrial applications, another as an inhibitor of mold and bacteria in food and the fourth as an ingredient in products ranging from shoe polish to pesticides, as well as in the preparation of explosives.
The researchers found multiple sensors that showed marked fluorescent responses when exposed to the four test substances.
What is also crucial, the researchers found out, is the order of the compounds along the DNA backbone. Like the sequence of natural DNA, which varies among different animals, the different sequences of the artificial DNA sensors gave different color changes.
Full story: DNA puts Stanford chemists on scent of better artificial nose…
Abstract in Angewandte Chemie: Polyfluorophores on a DNA Backbone: Sensors of Small Molecules in the Vapor Phase