Scientists have created living robots: blob-like lifeforms of frog stem cells that can be "programmed" to move. The robots are a far cry from the boxy, metal and plastic robots we're accustomed to. These living robots, named xenobots for the frog species that donates the necessary cells, might transform medicine in a way synthetic robots can't. For example, the xenobots can even heal themselves when injured.
Biologists have been working with robotics for at least the past couple of decades. Biologically-inspired design has led to robots that mimic the agility of cockroaches or gecko-like robots with pressure-sensitive adhesive "feet." The xenobots don't conform to this traditional version of a robot; they're not made from synthetic materials and don't execute lines of code. Instead, the xenobots are designed by supercomputers and are made of cells.
Xenobots are a development from the field of evolutionary robotics, which applies principles of natural selection to the design of robots. Josh Bongard, a computer scientist at the University of Vermont and one of the creators of these robots, specializes in evolutionary robotics. According to The Scientist, he shared some theoretical designs of a cellular robot produced by his algorithm with colleagues at Tufts University. Douglas Blackiston, a microsrugery expert at Tufts, made the theoretical design a reality, building the robot from frog embryo cells.
Building the Biobot
Here's how it worked according to the study, published in the Proceedings of the National Academy of Sciences: The scientists gave the supercomputer a description of the biological building blocks they're working with and what behaviors they want the organism to do. In this case, the building blocks were frog stem cells that would become skin and cardiac cells. The supercomputer then runs through evolutionary algorithms and simulations, coming up with the best design for the robot via a sort of computational natural selection. Simulated designs that don't produce the best results are discarded, while successful designs are further tested.
The final product is a tiny live robot, sculpted from frog skin and cardiac cells. Image from Kriegman et al.
Once the team has the design, they extract cells from frog embryos fated to become skin and heart cells, grow the cells more, and use microsurgery techniques to sculpt the cells according to the algorithm's blueprint. The skin cells provide structure, while the heart cells, since they normally contract to beat the heart, provide movement functionality. The scientists equipped these robots with enough nutrients to survive for a little more than a week. The finished products are blob-shaped robots less than a millimeter in size that can move across a petri dish on their own.
One of the things living robots might be able to do that traditional robots can't is deliver medicine in new ways. Xenobot-like creations could play a role in targeted therapies, delivering medicine to specific cell types. Patients might one day be able to swallow a pill containing a biobot that can deliver drugs to a tumor, or scrape off plaque from arteries. If the technology advances enough to use human cells, cells from individual patients could be used to make the robots, which could eliminate harmful reactions from the immune system that can occur with other drugs.
Another benefit is that xenobots are made from cells. They're not made with metals that could harm a person or the environment as they age. Because of this property Xenobots may be used to clean the environment without further contaminating it. For example, the cells could be programmed to capture and digest toxins or microplastics in the ocean.
The research team also says that the xenobots are a step toward answering more fundamental questions about medicine and anatomy. Stated on their website: "The big question here is: how do cells cooperate to build complex, functional bodies?" The ability to make biological forms could correct serious medical problems, like birth defects or serious injuries.
The heart cells, pictured in red, contract to move the robot. Image from Kriegman et al.
For anyone concerned about live robots evolving to take over the world, that's unlikely. "Obviously there's a lot of public concern about this technology," said Bonguard in the CNN interview. "We're working with our regulatory colleagues to make sure this technology is used well." The organisms do not have any reproductive organs, so they can't create more robots on their own or evolve new capabilities and traits.
While creating a robot of live tissues raises ethical concerns, at this point, the robots have no nervous system and can't feel anything. These issues could be more relevant with future robotic designs. "What's important to me is that this is public, so we can have a discussion as a society and policymakers can descide what is the best course of action," Sam Kriegman, a PhD student at the University of Vermont and lead author on the study told The Guardian.