Cells form on their own into living “ xenobots ”
The potential of cells to find their way to bodily planes was dramatically illustrated recently with a report that when some sea slugs are heavily infected with parasites, their head separates from the body by self-induced decapitation, then grows back a whole new body within weeks. It’s tempting to see this as an extreme case of regeneration, but this prospect leaves some deep questions unanswered.
“First, where does the information about the anatomy he’s trying to regenerate come from?” Levin asked. “It’s easy to say ‘genome’, but we now know from our xenobots that there is extreme plasticity, and cells are actually willing and able to build very different bodies.”
The second question, he says, is how regeneration knows when to stop. “How do cells know when the final ‘correct’ shape has been produced and can they stop remodeling and growing?” He asked. The answer is key to understanding the nastiness of cancer cells, he thinks.
Levin’s group is currently investigating whether adult human cells (which lack the versatility of embryonic cells) display a similar ability to assemble into “robots” if given the chance. Preliminary results suggest this is the case, according to the researchers.
Organisms, living machines or both?
In their article, Levin and his colleagues discuss the potential of xenobots as “living machines” that could be used as microscopic probes or deployed in swarms to perform collective operations such as cleaning up aquatic environments. Adami, however, remains to be convinced that the Tufts team understands enough to start doing it. “They haven’t shown that you can design these things, that you can program them, that they do anything that isn’t ‘normal’ once you release the mechanical stresses,” he said. .
Levin is not discouraged, however, and believes that the ramifications of xenobots for basic science may ultimately extend far beyond their biomedical or bioengineering applications, to any collective system that presents an emerging design not specifically coded in. its parts.
“I think it’s bigger than even biology,” Levin said. “We need a science of where the goals come from on a larger scale. We’re going to be surrounded by the Internet of Things, by swarm robotics, and even by businesses and businesses. We don’t know where their goals come from, we’re not good at predicting them, and we’re certainly not good at programming them. “
Solé shares this larger vision. “This work is particularly remarkable for all that it reveals about the generating potential of self-organization,” he said. He thinks it might broaden our view of how nature creates its infinite forms: “One thing we know as well is that nature is constantly tinkering with biological matter and that different functions or solutions can be achieved by different combinations of. rooms. Perhaps an animal, even a human, is not an entity set in stone – or rather, in DNA – but is only a possible result of decision-making by cells.
But are xenobots “organisms”? Absolutely, says Levin – provided we adopt a common sense of the word. A set of cells that has clear boundaries and well-defined, collective, goal-directed activity can be considered a “self”. When xenobots meet and bond temporarily, they don’t merge; they maintain and respect their identity. They “have natural boundaries that set them apart from the rest of the world and allow them to have consistent functional behaviors,” Levin said. “It’s at the heart of what it means to be an organization.”
“These are organizations,” Jablonka agreed. It is true that xenobots probably cannot reproduce, but neither can a mule. Additionally, “a xenobot can be made to fragment and form two small ones,” she said, “and maybe some cells will divide and differentiate into motile and non-motile cells.” If so, xenobots might even undergo some sort of evolution. So who knows what might become of them?
Original story reprinted with permission from Quanta Magazine, an editorially independent publication Simons Foundation whose mission is to improve public understanding of science by covering developments and research trends in mathematics and the physical and life sciences.
More WIRED stories