Scientists at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany and Harbin Institute of Technology in Shenzhen, China have come up with a tiny self-powered propulsion system for devices small enough to move through various vessels inside our bodies. The technique does not generate any bubbles to push microscopic objects, but instead works similar to a jet engine that pushes air through itself to generate thrust.
These microengines consist of nanotubes made of silicon dioxide. They are coated with the enzyme urease that reacts with urea, turning it into ammonia and carbon dioxide. As the nanotubes encounter urea, the reaction occurs and forces liquid to move through the tube. Any irregularities within the structure of the nanotube and/or the distribution of urea over the nanotube determines its direction of motion.
These nanotube engines, the smallest jet engines ever made, may eventually be attached to devices that deliver drugs or perform some other diagnostic or therapeutic task.
Study in Journal of the American Chemical Society: Bubble-Free Propulsion of Ultrasmall Tubular Nanojets Powered by Biocatalytic Reactions…