How Scientists Turned Frog Embryos into Living, Self-Replicating Robots

Frog Embryo

Scientists at the University of Vermont, Tufts University, and Harvard University's Wyss Institute of Biologically Inspired Engineering, who built xenobots, the world's first living robots, have discovered that the very same organisms they made in 2020 have the ability to create new versions of themselves by banding together. 

report published by The Wyss Institute reveals that the hand-assembled, computer-designed xenobots can self-replicate by swimming out and gathering single cells to assemble "baby" versions of themselves inside their mouths. After a few days, the new bots start to move and look exactly like their "parents."

Xenobots, scraped from frog embryos and then assembled to create new life forms using a supercomputer at the University of Vermont, were first introduced in 2020. Back then, the scientists found that although the xenobots are each around a millimeter-wide, they can together move toward a target, pick up a payload, and heal after being cut. Their latest discovery shows that the bots can go out, find cells, and replicate themselves repeatedly. 

"This is profound. These cells have the genome of a frog, but, freed from becoming tadpoles, they use their collective intelligence, a plasticity, to do something astounding," said Michael Levin, Ph.D., professor of biology and director of the Allen Discovery Center at Tufts University and co-lead of the new research, in a statement. 

Early in their research, Levin noted that they were already amazed at the xenobots' ability to perform simple tasks, so the fact that they can spontaneously replicate is remarkable. Although composed of frog cells, the xenobots are behaving in ways that are different from how frogs do. According to lead author Sam Kriegman, Ph.D., no plant or animal to date replicates in this manner. 

Throughout their research since building xenobots, the scientists have been allowing the UVM supercomputer to determine how to adjust the xenobot parents' shapes, which was a sphere made up of around 3,000 cells. One of the shapes that the machine came up with is one that resembles Pac-Man from the famous video game. 

They further studied what the Pac-Man-shaped xenobot can do and arrived at this result: that it can make its own children, grandchildren, and later generations of itself. This type of kinematic replication has reportedly never been seen before on a cellular level. 

The discovery bodes well for the field of medicine, which is currently under pressure to discover and develop treatments as fast as new types of illnesses come up. In the age of the ever mutating COVID-19, knowing how technology can contribute to finding solutions is encouraging. 

"If we knew how to tell collections of cells to do what we wanted them to do, ultimately, that's regenerative medicine — that's the solution to traumatic injury, birth defects, cancer, and aging. All of these different problems are here because we don't know how to predict and control what groups of cells are going to build. Xenobots are a new platform for teaching us," added Levin. 

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