Nanoengineers at the University of California, San Diego, have developed 3D printing technology called “microscale continuous optical printing” that can print hundreds of microrobots within seconds, each one smaller than the width of a single hair.

The researchers have been working with fish-shaped microrobots that they’ve dubbed “microfish,” which they’ve found can swim around efficiently in liquids, according to a news release they posted in EurekaAlert.

They placed the microfish in hydrogen peroxide and added platinum nanoparticles to their tails; the particles interacted with the liquid, propelling the microfish forward. The researchers then added magnetic iron oxide nanoparticles to the microfish heads, allowing them to steer the microrobots with magnets.

Wei Zhu, a nanoengineering Ph.D. student who co-authored the report, wrote that “the microfish can doubly serve as detoxification systems and as toxin sensors.” When the researchers incorporated toxin-neutralizing nanoparticles into the microfish bodies, they found that their powerful swimming ability allowed them to efficiently clean out toxins from the solution. When the particles interacted with toxins, they emitted a red glow; the greater the presence of toxins, the greater the intensity of the glow.

The researchers are exploring the possibility of using this as a medical tool. They want to incorporate medicine into the microfish so that they can be injected into someone’s system in order to distribute drugs.

Jinxing Li, another nanoengineering Ph.D. student and co-author, says that it is his “personal hope to further this research to eventually develop surgical microrobots that operate safer and with more precision.”