Researchers at the UCSD nanoengineering department recently created fish-shaped micro-robots using original 3-D-printing technology. Professors Shaochen Chen and Joseph Wang of the UCSD nanoengineering department led the study, which was published in the journal Advanced Materials last month.

Nanoengineering Ph.D. student and research team member Wei Zhu explained the applications of this technology and why it was important in a press statement.

“We have developed an entirely new method to engineer nature-inspired microscopic swimmers that have complex geometric structures and are smaller than the width of a human hair. With this method, we can easily integrate different functions inside these tiny robotic swimmers for a broad spectrum of applications,” Zhu said.  

These fish-shaped micro-robots could potentially lead to a new production of micro-robots with a diverse range of abilities including, but not limited to, detoxification, sensing, directed drug delivery and environmental cleanup.

The researchers created the micro-robots through microscale continuous optical printing, a unique technology that allows multiple layers of useful nanoparticles in a design — a previously-unavailable function. The technology used to create these microrobots was the first of its kind and has several advantages over previous versions.

Jinxing Li, a nanoengineering Ph.D student in Wang’s research group, explained that this function facilitated the team’s research and has potential to improve surgical technology.

“This method has made it easier for us to test different designs for these microrobots and to test different nanoparticles to insert new functional elements into these tiny structures. It’s my personal hope to further this research to eventually develop surgical microrobots that operate more safely and with more precision,” Li said.  

The micro-robots were able to swim efficiently because they were chemically powered by hydrogen peroxide and magnetically controlled, which was made possible by using the 3-D-printing technology. Particles, such as platinum nanoparticles, were inserted in the tails and magnetic iron oxide was inserted in the heads, allowing the micro-robots to move forward and be controlled with magnets.

Furthermore, the scientists conducted an experiment by implanting polydiacetyline in the bodies  of the micro-fish. Polydiacetyline is a powerful particle able to capture harmful toxins, such as the pore-forming toxins found in bee venom. In this experiment, the micro-robots glowed red as the polydiacetyline bound to the toxins. The scientists found that the swimming abilities of the fish-shaped micro-robots, combined with polydiacetyline, allowed them to remove toxins from solutions.

Zhu explained that the results of the experiment provided researchers with knowledge about the multiple functions of the micro-fish. 

“The neat thing about this experiment is that it shows how the micro-fish can doubly serve as detoxification systems and as toxin sensors,” Zhu said.

However, the researchers say that micro-fish are only the beginning of a new era of micro-robots that could someday be used to perform greater functions. In fact, they could one day deliver targeted medicinal packages in a human bloodstream. 

They may also one day execute microscopic surgeries and take many forms, according to Zhu.

“With our 3-D printing technology, we are not limited to just fish shapes. We can rapidly build microrobots inspired by other biological organisms such as birds,” Zhu said.