Researchers at Harvard's Wyss Institute have coaxed single strands of DNA to fit together like Lego bricks and form scores of complex three-dimensional shapes, including a teeny-tiny space shuttle. The technique, described in this week's issue of the journal Science, adds a new dimension to molecular construction and should help open the way for nanoscale medical and electronic devices. “This is a simple, versatile and robust method,” the study's senior author, Peng Yin, said in a news release. The method starts with synthetic strands of DNA that take in just 32 nucleotides, or molecular bits of genetic code. These individual “bricks” are coded in a way that they fit together like Lego pegs and holes to form larger shapes of a specific design. A cube built up from 1,000 such bricks (10 by 10 by 10) measures just 25 nanometers in width. That's thousands of times smaller than the diameter of a single human hair.
The latest research builds upon work that the Wyss researchers detailed in May, which involved piecing together DNA strands to create two-dimensional tiles (including cute smiley faces). This time around, the strands were twisted in such a way that they could be interlocked, Lego-style. As any visitor to Legoland knows, such structures can get incredibly complex in the hands of a skilled builder. Yin and his colleagues are still learning their building techniques. Fortunately, the bricks could be programmed to build themselves, with the aid of 3-D modeling software. Once the designs were set, the researchers synthesized strands with the right combinations of nucleotides — adenosine, thymine, cytosine and guanine — so that when they were mixed together in a solution, at least some of the bricks would form the desired design. To demonstrate the method, 102 different 3-D shapes were created using a 1,000-brick template.