Tiny ‘xenobots’ assembled from cells promise advances from drug delivery to toxic waste clean-up
A book is made of wood. But it is not a tree. The dead cells have been repurposed to serve another need.
Now a team of scientists has repurposed living cells—scraped from frog embryos—and assembled them into entirely new life-forms. These millimeter-wide “xenobots” can move toward a target, perhaps pick up a payload (like a medicine that needs to be carried to a specific place inside a patient)—and heal themselves after being cut.
These are novel living machines. They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.
The new creatures were designed on a supercomputer at UVM (University of Vermont)—and then assembled and tested by biologists at Tufts University.
These living robots can be useful in various ways, like searching out nasty compounds or radioactive contamination, gathering microplastic in the oceans, traveling in arteries to scrape out plaque.
The results of the new research were published in the Journal Proceedings of the National Academy of Sciences.
People have been manipulating organisms for human benefit since at least the dawn of agriculture, genetic editing is becoming widespread, and a few artificial organisms have been manually assembled in the past few years—copying the body forms of known animals.
But this research, for the first time ever, designs completely biological machines from the ground up.
With months of processing time on the Deep Green supercomputer cluster, the team used an evolutionary algorithm to create thousands of candidate designs for the new life-forms. After a hundred independent runs of the algorithm, the most promising designs were selected for testing.
Then the team at Tufts, transferred the in silico designs into life. First they gathered stem cells, harvested from the embryos of African frogs, the species Xenopus laevis. (Hence the name “xenobots.”) These were separated into single cells and left to incubate. Then, using tiny forceps and an even tinier electrode, the cells were cut and joined under a microscope into a close approximation of the designs specified by the computer.
Assembled into body forms never seen in nature, the cells began to work together. The skin cells formed a more passive architecture, while the once-random contractions of heart muscle cells were put to work creating ordered forward motion as guided by the computer’s design, and aided by spontaneous self-organizing patterns—allowing the robots to move on their own.
These reconfigurable organisms were shown to be able move in a coherent fashion—and explore their watery environment for days or weeks, powered by embryonic energy stores.
Later tests showed that groups of xenobots would move around in circles, pushing pellets into a central location—spontaneously and collectively.
Your laptop is a powerful technology. But try cutting it in half. Doesn’t work so well. In the new experiments, the scientists cut the xenobots and watched what happened. They sliced the robot almost in half and it stitches itself back up and keeps going.
News Source: UVM
