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.