Known as Xenobots are living robots made from the stem cells of the African frog (Xenopus Laevis)—had already wowed researchers with their ability to move, heal themselves, and even spontaneously pile up debris. However, when the small synthetic particles were replaced with loose stem cells, the little living bots performed an amazing feat: they fused the cells together, resulting in the formation of new Xenobots.
These are frog cells replicating in a manner not found in frogs. Nobody knows of any animal or plant that replicates like this,” says Sam Kriegman, co-author of the PNAS paper describing the discovery.
Human skin stem cells cultured in saltwater gave rise to Xenobots. In this way, the clumps developed cilia, allowing them to move independently. This behavior led the researchers to wonder if loose cells would behave similarly.
The answer is yes, and the mounds of cells they generate become new functional xenobots. As the scientists explain in their research, “clusters of cells can similarly identify and combine loose cells into clusters that appear and move as they do”—a process known as kinetic replication. Additionally, they state that “this skill does not have to be acquired through genetic modification or evolution.”
The scientists then utilized AI to forecast which Xenobot designs would be most efficient at gathering. The researchers then evaluated the supercomputer’s design against others by painstakingly cutting the naturally spherical Xenobots into varied forms. The algorithm anticipated that the small Cs would create the most “baby” Xenobots, culminating in numerous “generations” of bots. According to co–lead author and University of Vermont computer scientist Josh Bongard, such kinematic replication is not known from the tree of life.
The ability to replicate adds to the robots’ potential utility. Kriegman tells The Washington Post that while Xenobots aren’t now commercially viable, they may be used to clean up microplastics from the ocean or safely deliver medications to humans.
The researchers hope to create biological robots from mammalian cells, according to the Post. They want to make robots smart enough to operate without human assistance. As Kriegman tells the publication, such work requires extra ethical attention. Dr. Kriegman assures that Xenobots would never go uncontrollable and create a robot apocalpsy. According to him, changing the sodium concentration of the water or adding a bit of copper to their plate is enough to kill the sensitive bots.