Fluorescent image demonstrating the detoxification capability of 3D-printed microfish. (W. Zhu and J. Li/UC San Diego Jacobs School of Engineering)

Researchers from the University of California-San Diego have created 3D-printed “microfish” — each 120 microns long and 30 microns thick (thinner than a strand of human hair) — that can swim around in fluids and then perform tasks such as detect and neutralize toxins.

While the concept of microbots performing similar types of tasks has been around ever since Richard Feynman delivered his famous talk “There’s Plenty of Room At the Bottom” in 1959, one factor that makes this new microfish research initiative from Professors Shaochen Chen and Joseph Wang of the NanoEngineering Department at the University of California-San Diego so unique is that these microfish have a new source of locomotion that makes them easier to steer and control.

The microfish are essentially equipped with tiny hydrogen peroxide motors in their tails, which give them a chemical source of propulsion. In addition, they can be steered with the use of magnets, thanks to magnetic nanoparticles inserted in their heads. In short, they are chemically powered and magnetically controlled.

This combination of nanoparticles essentially creates a propulsion system for navigating fluids for the microfish – turning them into what the researchers at the Jacobs School of Engineering at the University of California, San Diego refer to as “tiny robotic swimmers.” In a paper that appeared in the August 12 issue of Advanced Materials, they suggest that the microfish could even be engineered to have different shapes that go far beyond today’s spheres and cylinders typical of other microbots — you might even be able to 3D-print sharks or manta rays. (If you’re afraid of sharks in the ocean, wait until microsharks are swimming around in waters near you, perhaps cleaning up a toxic spill).

The image of the microfish at work truly appears to be otherworldly. That’s because when they come into contact with pore-forming toxins and bind with them, the microfish are engineered to turn a bright fluorescent red. In such a way, you can watch red glowing microfish, clustering in schools to neutralize toxins, such as those from honeybees, spiders or sea anemones. If the microfish turn bright red, it means they’re hard at work.


3D-printed microfish contain functional nanoparticles that enable them to be chemically powered and magnetically steered. (J. Warner/UC San Diego Jacobs School of Engineering)

That might be just the beginning of new roles for these microbots, given recent advances in nanomedicine. If they can be made sufficiently small, the next task for these microfish after detecting and neutralizing toxins might be acting as drug delivery agents within the human body. That’s right — the next fluids these microfish might be navigating might be those within the human body.

“Another exciting possibility we could explore is to encapsulate medicines inside the microfish and use them for directed drug delivery,” said Jinxing Li, co-first author of the microfish paper and a nanoengineering PhD student in Wang’s research group.

With the idea of microbots and drug delivery systems, you’re getting into Ray Kurzweil territory and the whole concept of self-repairing nanobots inside the human body. As Kurzweil describes it, it’s basically humanity’s destiny to have nano repair modules coursing through our bodies, doing everything from making repairs to our immune systems to proactively searching for signs of disease. By 2040, Kurzweil says, we’ll practically be immortal, thanks to all the microscopic nanobots inside of us.

The easiest way to think about this is by thinking of the anatomy of the fish. You’ve got platinum nanoparticles in the tail and iron oxide nanoparticles in the head, but what about the rest of the body? That could open up a whole new set of possibilities. In short, you’re moving away from a purely biological or chemical process to an engineered process that involves “tiny machines,” each built with a specific purpose and carrying a specific payload.

Finally, there exist the potential for new types of radical surgical procedures using microbots similar to the 3D-printed fish. In one scenario, these microbots could help surgeons to become more precise with their techniques. It’s still very speculative, but the researchers at UCSD are hopeful it might happen one day, especially given the array of unique shapes that might be possible as a result of 3D printing.

“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,” Li said.

The next big step, of course, is to get Silicon Valley interested in the potential of these microfish. This seems like it might be possible. After all, you don’t have just one exponential technology at work here – you have two. You have the combination of 3D-printing technology with the latest advances in nanomedicine, two different disciplines with a combined ability to fundamentally change the way we think about health and medicine by thinking really small instead of really big.