From glass to space, the world of 3D printing is moving at light-speed. Nanoengineers at the University of California, San Diego are aiming small, microscopic small. Using a revolutionary 3D printing technology, these scientists created a multipurpose fish-shaped microrobot – called microfish.
One day, these microfish could swim around your bloodstream and deliver drugs right to the areas that need it.
“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,” said the co-first author Wei Zhu, a nanoengineering Ph.D. student at the Jacobs School of Engineering at UC San Diego.
These microfish are chemically powered and magnetically controlled
The typical microrobot can’t perform complicated tasks because of their simple designs. Most are spherical or cylindrical shaped and lack the features to perform more difficult tasks.
The researchers, led by Professors Shaochen Chen and Joseph Wang, created custom-built microfish to do more. The new 3D printing process allows the researchers to incorporate layers of functional nanoparticles into the microfish. One of these is platinum nanoparticles in the tail. When placed in hydrogen peroxide, the platinum nanoparticles produce a chemical reaction that thrusts the fish forward. Boom! There’s your propulsion.
Toss some magnetic iron oxide nanoparticles in the heads and you can now steer it with magnets.
For the proof-of-concept demonstration, the researchers mixed in some polydiacetylene (PDA) nanoparticles, which captures harmful toxins, with the microfish bodies. As PDA binds with the toxins, it becomes fluorescent and glows red. By monitoring the intensity of the red glow, the researchers can monitor how well the microfish are detoxifying.
Fluorescent image of the microfish showing their detoxification capability. Credit: W. Zhu and J. Li, UC San Diego Jacobs School of Engineering
“Another exciting possibility we could explore is to encapsulate medicines inside the microfish and use them for directed drug delivery,” said Jinxing Li, the other co-first author of the study.
The innovative 3D printing technology used in this study isn’t just limited to fish-shaped microrobots. “We can rapidly build microrobots inspired by other biological organisms such as birds,” said Zhu.
The technology that made the microfish possible is based on a rapid, high-resolution 3D printing technology known as microscale continuous optical printing. Developed in Chen’s lab, one of the major advantages of this technology is flexibility. In just seconds, researchers can print hundreds of microfish. And since the technology is digitized, different designs can be swapped out quickly.
“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 safer and with more precision,” said Li.