For instance, platinum nanoparticles in the tail react with hydrogen peroxide to power the microfish like a rocket, while iron oxide in the head lets researchers guide them with magnets -- much like other swimming nanobots we saw recently. Once the bots are in a desired location, a treatment can be released. To prove it worked, the team added a nanoparticle compound that removes bee venom and other "pore-forming" toxins from the body. Since the reaction also makes the compound glow, the researchers were also able to monitor its effectiveness by measuring the intensity of the light.

The system also holds potential to target drugs in the body, a popular goal for nearly every nanobot we've covered. The team hopes to eventually build "surgical microrobots that operate safer and with more precision" -- even though so far, such bots have only been implanted in mice. Nevertheless, the micromirror technology the researchers created to build the fish is promising, and could be adapted to build a variety of useful microdevices.