Nanoscale Robo-Arm Precisely Controlled by Electric Fields

DNA origami has been used to build many things on the nanoscale, but making a 3D shape is not the same as making a machine. Now, scientists in Germany have shown they can control a nanoscale DNA arm from the outside world. The technique relies on the negatively charged nature of DNA. The 25-nanometer arm is made up helices of somewhat rigid double-stranded DNA and is attached to a tiny DNA platform through a flexible single strand of DNA. The researchers, who published their work in Science, applied an electric charge to the system to move the arm around and could track its position using fluorescent signals picked up by microscopy. Precise, computer-controlled switching of the arm between arbitrary positions on the platform can be achieved within milliseconds.