Last year we wrote about how researchers at the University of Vermont and Tufts University were able to create what they call xenobots – the world’s first living, self healing robots created from frog stem cells.

Now, the same team has created an upgraded version of these robots that they have dubbed Xenobots 2.0. These upgraded robots have the ability to self-assemble a body from single cells, do not require muscle cells to move, and demonstrate the capability to record memory. In comparison to the previous version developed, Xenobots 2.0 can move faster, navigate different environments, have longer lifespans, and still have the ability to work together in groups and heal themselves if damaged. 

To create Xenobots 2.0, researchers at Tufts University took stem cells from embryos from the African frog Xenopus laevis (which is where the name Xenobots is derived from). The team then allowed the stem cells to self assemble and grow into sphere-like shapes. In a few days, these newly formed stem cell spheroids produced tiny hair-like projections, allowing them to move back and forth or rotate in a specific way.

Meanwhile, scientists at the University of Vermont were running computer simulations that modeled different shapes of the Xenobots to see if they might exhibit different behaviors, both individually and in groups. The team ran hundreds of thousands of random environmental conditions using an evolutionary algorithm and used these simulations to identify the Xenobots most able to work together in swarms to gather large piles of debris in a field of particles. What they found was that Xenobots 2.0 are much faster and better at tasks such as garbage collection. They can also cover large flat surfaces or travel through narrow capillaries.

Going one step further for Xenobots 2.0, the researchers at Tufts University engineered the Xenobots in a way to enable them to record one bit of information. By introducing a fluorescent protein, they were able to get the Xenobots to glow green normally. However, if the Xenobots were exposed to blue light, they would start to glow red instead.

To test this memory function, the team allowed ten Xenobots to swim around a surface on which one spot is illuminated with a beam of blue light. After two hours, they found that three bots glowed red and the rest remained green, effectively recording their travel experience.

In a press release, robotics expert Josh Bongard from the University of Vermont who played an integral role in this study elaborated on what these findings could implicate.

“When we bring in more capabilities to the bots, we can use the computer simulations to design them with more complex behaviors and the ability to carry out more elaborate tasks. We could potentially design them not only to report conditions in their environment but also to modify and repair conditions in their environment.”

Xenobots 2.0 were also able to heal quite rapidly, closing the majority of a deep cut half their thickness within 5 minutes of the injury. All injured bots were able to ultimately heal the wound, restore their shape, and continue their work as before.

In the same press release, Dr. Michael Levin, professor at Tufts University and corresponding author of the study, had this to say.

“The biological materials we are using have many features we would like to someday implement in the bots – cells can act like sensors, motors for movement, communication and computation networks, and recording devices to store information. One thing the Xenobots and future versions of biological bots can do that their metal and plastic counterparts have difficulty doing is constructing their own body plan as the cells grow and mature, and then repairing and restoring themselves if they become damaged. Healing is a natural feature of living organisms, and it is preserved in Xenobot biology.”

The full results of this study were published in Science Robotics.

You can learn more about this research from Dr. Michael Levin by watching his TED Talk linked below: