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.

Transcript

00:00:01 DNA robots just got a remote control. This microscopic robotic arm is self-assembled and made up of folded DNA. It’s a kind of DNA origami, which has been used to build many things on the nanoscale-- miniscule letters, teddy bears, even the Mona Lisa. Now researchers have shown the ability to remotely control a nanoscale DNA device. The robot arm rises up out of  a flat DNA platform on a glass slide.

00:00:31 While the arm is made out of relatively rigid DNA helices bundled together, It’s attached by flexible single-stranded DNA pieces that allow it to rotate. The technique relies on the negatively charged nature of DNA. The researchers applied a charge to the system to move the arm around and tracked its position using fluorescent signals picked up by microscopy. The movement happens within milliseconds. one-millionfold faster than previous examples

00:00:57 in DNA nanotechnology. In some experiments, the arm’s movement was stopped short by DNA strands sticking up perpendicularly from the platform. The arm could only move if the charge was driving it to let go of these complementary strands-- and then only to set positions. This shows that the DNA arm can move like a latch between predefined configurations, under remote control.

00:01:23 If combined with cargo transfer techniques these tiny DNA robot arms could be used to remotely pick up and drop off molecular components-- opening the door to true 3D printing of molecules.