A team of scientists working at the Naval Research Laboratory and the National Institute of Standards and Technology (NIST) have discovered that some DNA is surprisingly sticky around gold. The unexpected results are described in a Communication in the July 30, 2003 issue of the Journal of the American Chemical Society, with the article featured as an "Editor's Choice" in the July 25, 2003 issue of Science.
Many biotechnology products use gold to hold single strands of DNA on a surface for analysis. One example is so-called "DNA chips" used to detect genetic defects. And in the new field of nanotechnology, gold is often present to anchor DNA molecules between microscopic components. "However," reports Dr. Michael Tarlov, who conducted the NIST portion of the work with Dr. Hiromi Kimura-Suda, "we have discovered that strands of DNA made from adenine-one of the four letters, or bases, that make up the DNA alphabet-stick to gold much better than the others." In fact, in mixtures of different strands, "A" keeps the gold to itself, preventing the other bases from sticking.
An even more surprising result occurred when the scientists dipped gold in a solution of whole DNA made from strands of A bound to its complement, T (thymine). As Dr. Lloyd Whitman, who conducted the NRL portion of the research, explains, "The normally stable combination unexpectedly broke apart, again leaving only A stuck to the surface." "These new results should help scientists to better control the DNA in biotechnology and nanotechnology applications," concludes NRL co-author Dr. Dmitri Petrovykh.