Nanotubes filled with a benign rocket fuel could be used to carry drugs to specific parts of the body. Past research has shown that nanotubes filled with conventional rocket fuel (such as hydrazine) can power themselves through liquids at high speeds.
The problem here is that rocket fuels are poisonous to humans. The minute rockets have now been engineered to work with a less toxic fuel.
Scientists at the Leibniz Institute for Solid State and Materials Research in Dresden, Germany, made nanotubes by rolling platinum-coated sheets of metal into tubes.
When placed in warm, dilute hydrogen peroxide bubbles of gas are forced out of the end of the tube causing thrust.
The clever bit of this relies on platinum being on the inside of the nanotube, as this catalyses the decomposition of hydrogen peroxide thereby releasing bubbles of oxygen.
The rocket is faster than the quickest bacteria, travelling at 200 times its own length a second. The researchers controlled the rocket’s direction with a magnetic field and the speed is also controllable by changing the temperature of the aqueous hydrogen peroxide.
The research is presented in the Journal of the American Chemical Society, DOI: 10.1021/ja205012j.