Now Starring DNA in (IMAX) 3-D

Motion capture technology has made films like Avatar possible. Now, motion capture may help DNA become the star of its own film by allowing researchers to follow the "complex folding and twisting" of molecules in three dimensions, says New Scientist's Stephen Battersby. A device called a plasmon ruler helps scientists do just that — made up of metal nanoparticles in which electrons vibrate at a natural frequency, the ruler works when different nanoparticles are put near each other and the different sets of vibrations, called plasmons, affect one another and take on a common resonant frequency, Battersby says. "The separation can be measured by shining a light on the pair of particles, as only light at the resonant frequency of the plasmon gets absorbed," he adds. But the problem is that only one dimension can be measured, and the ruler is "imprecise." In a new study in Science, researchers from the University of California, Berkeley, detail their plasmon ruler design, which they say fixes these problems. It is made of five gold bars, a few hundred nanometers long, arranged in the shade of a 3-D letter H. "The arrangement tunes the frequencies of plasmons in the bars, creating two sharp resonances instead of one. By detecting both these resonances, the movement of the central bar relative to the cage can be followed in three dimensions," Battersby says. Eventually, the researchers say, it may be possible to use this technology to make recordings of DNA or proteins inside the bodies of humans or animals in vivo.