ROBERT SIEGEL, host:
Take a second and imagine one of those yellow smiley faces. Now imagine 50 billion smiley faces floating in a drop of water. That is what scientists made using DNA. It turns out that in addition to holding our genetic code and being a basic building block of life, DNA is also great for making incredibly tiny structures.
NPR's Nell Boyce reports.
NELL BOYCE reporting:
For years chemists have been using DNA to build really simple shapes like cubes that are a thousand times thinner than a human hair. They've done it by laboriously designing small snippets of DNA that will hook themselves up into the desired form. But a new method for building things with DNA is much faster and easier, even a high school student could think up a shape, like a star or a snowflake, and then make a DNA version within a week.
Paul Rothemund came up with the idea at the California Institute of Technology in Pasadena.
Mr. PAUL ROTHEMUND (California Institute of Technology, Pasadena): Even by the time I was making smiley faces, I didn't really believe that the method worked as well as it did.
BOYCE: Rothemund's trick is this: instead of custom designing small snippets of DNA so that they sit together in a certain way, he borrows a single long strand of DNA from a harmless virus.
Mr. ROTHEMUND: And we take that very long, single strand of DNA, it's about 7,000 letters long, and then we add to it about 200 short DNA strands that I call staples.
BOYCE: The staples bring two distant parts of the DNA strand together so that it folds.
Mr. ROTHEMUND: We actually fold the DNA into any shape that we want, right? So in the case of the smiley face that I made, I actually fold the DNA into a disc, but then leave three holes for the two eyes and for the mouth.
BOYCE: Rothemund has developed a new computer program that can analyze a shape, figure out the right folding pattern, and then tell you what DNA staples you need to make that shape.
Mr. ROTHEMUND: It's really easy and fun, actually, to make whatever you want at the nano-scale. You design it in the computer, you order the DNA sequences, they come in the mail, you add a little bit of saltwater, you heat it up and cool it down and then, you know, and hour and a half later, it's ready to look at under the microscope.
BOYCE: In this week's issue of the journal Nature, Rothemund shows off some of his DNA art. One nano-creation is a tiny map of the Americas. But the real goal of this work isn't tiny maps. Rothemund says that in the future, tiny DNA shapes could serve as scaffolds for quickly building nano-structures made of metals or other materials. Those could be useful for things like faster computers. Nell Boyce, NPR News.
SIEGEL: Images of DNA art are at our web site, NPR.org.
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