Propelling Nanorobots by Enzyme Action or Ultrasound
Injectable robots—sometimes called microswimmers—raise two sorts of engineering problems: design of the device itself, and its means of propulsion. In that field, engineers at the Max Planck Institute for Intelligent Systems (Stuttgart) have two new systems. The first is a 220 nanometer “swimmer,” made of silicon dioxide with one of its surfaces (inner or outer) coated with the enzyme urease, which breaks down to ammonia and carbon dioxide. It can move at a rate of almost four centimeters an hour, making it the world’s “smallest jet engine.” In the other system, engineers “. . . enclose the micro-bubbles in small cylindrical chambers along a plastic strip. To provide the drive, therefore, the gas bubbles expand and contract cyclically because ultrasound causes them to oscillate. As the pulsating bubbles are in chambers open on one side, they only expand through this opening. In the process, they exert a force on the opposite wall of the chamber which propels the plastic strip.” MORE
Image Credit: Max Planck Institute for Intelligent Systems News