This is exactly the approach that researchers in Prof Josh Bongard<\/a>\u2019s lab at the University of Vermont in the US are taking.<\/p>\n For the last four years, they have been designing and creating \u2018xenobots\u2019: miniature machines made from living frog cells.<\/p>\n Bongard explains the team\u2019s approach: \u201c[If you] make a robot out of metal and plastic \u2026 the pieces themselves have no intelligence.<\/p>\n \u201cWe\u2019re approaching robotics in a completely different way. We\u2019re building from components that are themselves fantastically intelligent machines.\u201d<\/p>\n Nature has been inspiring robotics for decades. It\u2019s led to actuators based on real muscles<\/a> that allow robots to move more easily. Elsewhere, pads that mimic geckos\u2019 feet let robots climb vertical glass<\/a>. Xenobots, by contrast, are made from nature\u2019s own building blocks.<\/p>\n According to Dr Victoria Webster-Wood<\/a>, an expert in biologically inspired robots at Carnegie Mellon University, this type of approach \u201cenables us to directly harness living materials\u2019 natural adaptability.\u201d<\/p>\n What\u2019s fascinating about Bongard\u2019s xenobots is that they can be made from normal cells taken from frog embryos \u2013 no genetic tweaks required.<\/p>\n Although scientists already knew these cells could move on their own, in this case they\u2019re being used as materials to generate predictable, robot-like behaviours, such as herding particles around a Petri dish, cooperating like sheepdogs and even birthing balls of other cells that might be regarded as xenobot babies.<\/p>\n While it\u2019s not clear what it is in the xenobots\u2019 internal workings, or rather those of the frog cells, that make them behave in this way, their capabilities do make them potentially useful for all manner of tasks.<\/p>\n Cleaning-up microplastics, for example, or, as the researchers outlined in their first paper on the xenobots<\/a>, published in 2020, crawling to the site of diseased tissues in humans to help restore them to health.<\/p>\n So if you\u2019re going to make a xenobot, where do you start? Well, the Vermont team starts in a virtual Petri dish, on a computer, where an artificial intelligence<\/a> (AI) program \u2018evolves\u2019 bunches of frog cells, based on their shape, to perform whatever task it is the scientists are interested in.<\/p>\n \u201cIt creates a population of virtual xenobots, deletes the ones that do a poor job and makes randomly modified copies of the survivors,\u201d explains Bongard.<\/p>\n The scientists tell the AI how many rounds of this artificial selection process to complete and in just a few seconds, they have their design.<\/p>\n As an example, that design might be a ball of cells with a hole in the middle, like a pouch, which works well for transporting objects.<\/p>\n It\u2019s the AI-based design process that\u2019s the \u201creal masterpiece\u201d of the team\u2019s approach, according to Dr Falk Tauber<\/a>, a bio-inspired technology expert based at the University of Freiberg in Germany.<\/p>\n Without the virtual Petri dish, he notes, testing hundreds of different cell configurations could take weeks or even months using real cells.<\/p>\n \u201cThis not only represents an immense time advantage, but also provides the opportunity to implement only the most promising approaches that have proven successful in [the computer],\u201d he says.<\/p>\n He suggests the AI approach could be useful in other scenarios too \u2013 like the rapid design of personalised organ transplants that precisely fit a patient\u2019s anatomy.<\/p>\n Read more:<\/strong><\/p>\n Then comes the time-consuming bit, as the virtual designs have to be transferred to the real-life cells. It\u2019s a process that takes the team\u2019s sole xenobot sculptor, biologist Dr Doug Blackiston<\/a>, based at Tufts University, Massachusetts, hours for each millimetre-scale xenobot.<\/p>\n Using microsurgery instruments, Blackiston painstakingly carves the shape designed by the AI into tissue harvested from frog embryos.<\/p>\n \u201cFor me, it\u2019s a lot like drawing or working on art,\u201d he says, adding that he enjoys seeing the shapes come together.<\/p>\n However, he admits that for the xenobots to find real-world applications, they\u2019ll need to speed up the process to create more than the current 30 to 40 xenobots a week. That advance could come from 3D printing, which can use cells and tissues as printing \u2018inks\u2019.<\/p>\n The xenobots then spend a little over a week crawling or swimming around a dish before disintegrating (as they don\u2019t eat, their lifespan is limited).<\/p>\n In their original experiments, the researchers made \u2018walking\u2019 xenobots from combinations of heart and skin cells; the piston-like action of heart cells translated into movement.<\/p>\n Now, though, they use skin cells, taking advantage of beating hair-like structures called cilia, which protrude from the outer surface of the balls of cells, allowing them to \u2018swim\u2019.<\/p>\n After initially seeing their movements, the researchers thought the xenobots might be capable of pushing things around, though they wondered if the xenobots would be strong enough.<\/p>\n \u201cI started with very light dye particles, littered across the bottom of the Petri dish like a fine layer of ash or snow,\u201d says Blackiston. \u201cI happened to get lucky on the first try and it worked.\u201d The xenobots could also push tiny glass beads around.<\/p>\n Read more:<\/strong><\/p>\n After the researchers progressed to making the swimming xenobots, they started giving swarms of them more interesting things to move around, like cells \u2013 the same cells of which the miniature robots themselves are composed.<\/p>\n That was when something intriguing began to happen: the swarm began pushing the cells into little piles. Frog cells are sticky so the piles tended to stay together and then, a few days later, hairs started to appear on their surface \u2013 cilia, just like on the surface of the xenobots.<\/p>\n \u201cAnd then,\u201d says Bongard, \u201cDoug [Blackiston] noticed that a couple of them started to move.\u201d<\/p>\n At this point, it was clear that the xenobots were making more of themselves. It wasn\u2019t a traditional \u2018have sex, make a baby\u2019 type of scenario, but it was a form of replication that had never been seen in nature.<\/p>\n According to Blackiston, he knew the experiment would work if he could get the conditions right. But that didn\u2019t make it any less exciting when he first showed Bongard and the team one of the \u2018children\u2019 moving around on a Zoom call.<\/p>\n \u201cIt was silent on the call \u2013 the biologists, the computer scientists,\u201d Bongard remembers. \u201cYou know, self-replication is kind of a dream and a hope [for] machines in general and to see it\u2026 it completely blew my mind.\u201d<\/p>\n When the researchers realised their xenobots could self-replicate, they told their AI to evolve versions that could do it better.<\/p>\n The AI set to work, designing a shape that looked pretty familiar: Pac-Man, or as Bongard puts it \u201ca shovel, basically\u201d, which makes sense when you\u2019re making your babies by pushing bits of them into piles \u2013 you can see an image of this below.<\/p>\n The fact that the xenobots are now capable of self-replication opens up a whole suite of potential applications, Bongard says, due to what he calls \u201cexponential utility\u201d.<\/p>\n The concept applies to any technology that does something useful and becomes more useful the further it spreads. Environmental clean-up is a good example, as well as vaccines, or technologies that could put out forest fires. These technologies don\u2019t spread on their own, though, so they could benefit from a self-replicating carrier to help them.<\/p>\n Although this is all just a theory, the researchers did show through computer modelling that if they fed the xenobots enough cells and they continued to replicate, then the xenobots use for a simpler application, such as moving wires around in a circuit, would continue to grow.<\/p>\n If self-replicating xenobots sound like the sort of sci-fi movie scenario we ought to avoid, the thing to remember is that the parent bots can only produce offspring under certain circumstances, which, as Webster-Wood points out, the researchers control.<\/p>\n Without access to additional free-floating cells, they can\u2019t replicate at all. Plus, the team\u2019s xenobots are biodegradable and \u2018die\u2019 in a matter of days.<\/p>\n As Tauber puts it, \u201cThese small cellular robots are safely housed in the laboratories of Bongard\u2019s team and could not \u2018live\u2019 in the outside world.\u201d<\/p>\n In fact, \u2018living\u2019 is not a label Tauber would apply to them at all, precisely because their survival depends on such specific conditions.<\/p>\n Bongard, though, believes that along with other technologies \u2013 like biohybrids that combine organic and technological components \u2013 the xenobots are starting to blur the line between living and non-living, reigniting the debate about what is life.<\/p>\n Meanwhile, the xenobots\u2019 behaviour has sparked other questions. For example, the researchers don\u2019t know whether the xenobots are really cooperating when they push cells and other objects around together.<\/p>\n Are they able to sense each other through the millions of different receptors that exist on the surface of living cells? Or are they just mindlessly moving around like wind-up toys?<\/p>\n Another intriguing question, of course, is whether biological robots could also be made from human cells \u2013 and whether it\u2019s a route the team is planning to take.<\/p>\n It\u2019s certainly on the to-do list, according to Bongard. \u201cYou know, frog and human cells diverged not that long ago, when you think about the total evolutionary history of cells,\u201d he muses, suggesting that, in principle, it should work.<\/p>\n Xenobots from human cells would be more compatible with medical applications, though there would be a long road to get them approved.<\/p>\n In the meantime, the researchers want to discover more about what it is in the frog cells\u2019 underlying biology that makes them behave as they do.<\/p>\n They hope to learn how to better manipulate the living materials to create better machines. That\u2019s something their AI is figuring out, but can\u2019t communicate to them yet. \u201cWe\u2019re asking the AI to make machines, but the repercussion of that is, along the way, the AI is learning more and more about biology,\u201d says Bongard.<\/p>\n A key part of the work, he adds, is getting the AI to explain what it has learned about biology back to \u201cus poor humans\u201d.<\/p>\n Prof Josh Bongard<\/strong> is head of the Morphology, Evolution and Cognition Laboratory at The University of Vermont. In 2007, he was awarded a Microsoft Research New Faculty Fellowship and was named one of MIT Technology Review\u2019s top 35 young innovators under 35.<\/p>\n Dr Falk Tauber<\/strong> is a postdoctoral researcher at the University of Freiburg. He is also the coordinator of the biotech livMatS demonstrator project.<\/p>\n Dr Doug<\/strong> Blackiston is a researcher at Tufts University and the Wyss Institute at Harvard University. His work has been published in journals including PloS One<\/em> and the Journal Of Experimental Biology<\/em>.<\/p>\n Read more:<\/strong><\/p>\n <\/p><\/div> <\/section> <\/body><\/html>\n Scientists are using living materials to make machines that some would regard as alive\u2026 and now they\u2019ve started to replicate <\/p>\n","protected":false},"author":24,"featured_media":26354,"template":"","categories":[1],"acf":{"readingTimeMinutes":"10"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots.jpg",1200,511,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots-300x128.jpg",300,128,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots-768x327.jpg",768,327,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots-1024x436.jpg",800,341,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots.jpg",1200,511,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/42\/2023\/04\/an-ai-created-robots-out-of-living-tissue-then-they-started-to-reproduce-meet-the-xenobots.jpg",1200,511,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"Scientists are using living materials to make machines that some would regard as alive\u2026 and now they\u2019ve started to replicate","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/rss_feed\/26353"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/media\/26354"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/media?parent=26353"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/wp-json\/wp\/v2\/categories?post=26353"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Artificial selection<\/strong><\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>Pushing to progress<\/strong><\/h2>\n
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<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>About our experts<\/strong><\/h3>\n
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