Mesmerizing Video Shows How Tiny 'Living Robot' Xenobot Cells Reproduce

Scientists have managed to create what have been referred to as "living robots"—tiny organisms that are able to make copies of themselves—and a video shows how the process works.

The living robots, called "Xenobots" by the scientists who worked on them, were created using cells from a type of frog, Xenopus laevis.

In nature, these cells would eventually have turned into skin on the outside of tadpoles.

But in the lab, they have been repurposed. Now, they replicate in a way that has never been observed before in living organisms, the scientists say.

"These are frog cells replicating in a way that is very different from how frogs do it," Sam Kriegman, lead author on the Xenobots study and a post-doctoral researcher at Tuft's Allen Center and Harvard University's Wyss Institute for Biologically Inspired Engineering, said in a press release. "No animal or plant known to science replicates in this way."

Footage of the cells in action from the University of Vermont can be seen below.

Although the Xenobots have been called robots in a University of Vermont press release, they aren't robots as we might imagine in science fiction. They are living organisms, sphere-shaped groups of stem cells, that were removed from their usual environment inside a frog and left to fend for themselves in a new place.

One of the problems the team had to tackle was that initially, in their new environment, the cells would replicate once and then usually die out.

So they decided to let a supercomputer—the Deep Green network at the University of Vermont—work out whether the cells would perform better if they were grouped into another shape instead of a sphere.

Over a period of months the supercomputer tested billions of different shapes before settling on "some strange designs," according to Kriegman, "including one that resembled Pac-Man."

Kriegman said the "Pac-Man" design isn't something a human engineer would have come up with because it didn't look as though it would be particularly effective, but in the lab the cells were able to create copies of themselves more than once using this shape, building children and grandchildren.

The Xenobots in this shape gather single cells in their mouths and then release new Xenobots that look and move like themselves.

This process has been observed before in molecules, which move around and combine building blocks into self-copies. The researchers say they have shown that living cells can do this too if freed from their developing organism, and don't need to be genetically manipulated to do so.

Their research, "Kinematic self-replication in reconfigurable organisms," was approved for publication in the journal Proceedings of the National Academy of Sciences (PNAS) in October this year.

Joshua Bongard, a computer scientist and robotics expert at the University of Vermont who co-led the research, said in a press release that the technology could one day be used in a variety of situations like pulling microplastics out of water or building new medicines.

"This is an ideal system in which to study self-replicating systems," he said, on the topic of whether having self-replicating biotechnology is risky. "We have a moral imperative to understand the conditions under which we can control it, direct it, douse it, exaggerate it."

Xenobot cell
An image of one of the Xenobots in action. Doug Blackiston and Sam Kriegman