The 'xenobot' is the world's newest robot -- and it's made from living animal cells
TORONTO -- Forget gleaming metal droids -- the robots of the future may have more in common with the average amphibian than with R2D2.
A team of scientists have found a way to not just program a living organism, but to build brand new life-forms from scratch using cells, creating what researchers are calling “xenobots.”
Tiny in size, but vast in potential, these millimetre-sized bots could potentially be programmed to help in medical procedures, ocean cleanup and investigating dangerous compounds, among other things.
"They're neither a traditional robot nor a known species of animal,” said researcher Joshua Bongard in a news release. “It's a new class of artifact: a living, programmable organism."
In the introduction for the research published in “Proceedings of the National Academy of Sciences” (PNAS) on Monday, researchers point out that the traditional building blocks we’ve used for robots and tech -- steel, plastic, chemicals, etc. -- all “degrade over time and can produce harmful ecological and health side-effects.”
After realizing that the best “self-renewing and biocompatible materials” would be “living systems themselves,” researchers decided to create a method “that designs completely biological machines from the ground up.”
The bots are made out of stem cells taken from frog embryos -- specifically, an African clawed frog called “xenopus laevis,” which supplied the inspiration for the name “xenobot.” To design the xenobots, the possible configurations of different cells were first modeled on a supercomputer at the University of Vermont.
The designs then went to Tufts University, where the embryonic cells were collected and separated to develop into more specialized cells. Then, like sculptors (if sculptors used microsurgery forceps and electrodes), biologists manually shaped the cells into clumps that matched the computer designs.
Different structures were sketched out by the computer in accordance with the scientists’ goal for each xenobot.
For example, one xenobot was designed to be able to move purposely in a specific direction. To achieve this, researchers put cardiac cells on the bottom of the xenobot. These cells naturally contract and expand on their own, meaning that they could serve as the xenobots’ engine, or legs, and help move the rest of the organism, which was built out of more static skin cells.
In order to test if the living robots were truly moving the way they were designed to, and not just randomly, researchers performed a test that has stumped many a living creature.
They flipped the robot on its back. And just like a capsized turtle, it could no longer move.
When researchers created further designs for the bots, they found that they could design them to push microscopic objects, and even carry objects through a pouch.
"It's a step toward using computer-designed organisms for intelligent drug delivery," says Bongard.
The possible uses for these tiny robots are numerous, researchers say.
“In biomedical settings, one could envision such biobots (made from the patient’s own cells) removing plaque from artery walls, identifying cancer, or settling down to differentiate or control events in locations of disease,” the research paper suggests.
A robot made out of metal or steel generally has to be repaired by human hands if it sustains damage. One major benefit that researchers found of creating these robots out of living cells was how they reacted to physical damage.
A video taken by the researchers showed that when one of their organisms was cut almost in half by metal tweezers, the two sides of the wound simply stitched itself back together.
These living robots, researchers realized, could repair themselves automatically, “something you can’t do with typical machines,” Bongard said.
Because they are living cells, they are also naturally biodegradable, Bongard pointed out. Once they’ve fulfilled their purpose, “they’re just dead skin cells,” making them even more optimal for usage in medical or environmental research.
Although scientists have been increasingly manipulating genetics and biology, this is the first time that a programmable organism has been created from scratch, researchers say.
This new research takes scientists a step closer to answering just how different cells work together to execute all of the complex processes that occur every day in animals and humans.
"The big question in biology is to understand the algorithms that determine form and function," said co-leader Michael Levin in the press release. He directs the Center for Regenerative and Developmental Biology at Tufts.
"What actually determines the anatomy towards which cells co-operate?” he asked. “You look at the cells we've been building our xenobots with, and, genomically, they're frogs. It's 100 per cent frog DNA -- but these are not frogs. Then you ask, well, what else are these cells capable of building? As we've shown, these frog cells can be coaxed to make interesting living forms that are completely different from what their default anatomy would be.”
Of course, a biological organism created and programmed by humans which is capable of healing itself might sound a little alarming. After all, one of the sponsors of the research is the Defense Advanced Research Projects Agency, which is affiliated with the U.S. military.
Researchers acknowledged in the press release that the implications around such technological and biological advancements can be worrying at times.
“That fear is not unreasonable,” Levin said. However, he believes that in order to move forward with science, we should not hold back from complex questions. “This study is a direct contribution to getting a handle on what people are afraid of, which is unintended consequences.
"I think it's an absolute necessity for society going forward to get a better handle on systems where the outcome is very complex," Levin says. "A first step towards doing that is to explore: how do living systems decide what an overall behavior should be and how do we manipulate the pieces to get the behaviors we want?"