what is the definition of life for a long time people have thought that we've worked out all the ways that life can exist on this earth there's the plants the fungi the multicellular animals the archaea the bacteria and the protists but this particular creature doesn't fall into any of these categories and its existence has sparked one of the greatest debates in modern science if you were to observe these organisms under a microscope you'd see them propel themselves around moving forward backwards sometimes spinning in a circle if you were to scatter some particles around them they
will round them up and make little piles organizing the debris their motion and behavior even resemble that of other microscopic organisms they are motile can heal damage retain information and even work together but these organisms were not born out of millions of years of evolution they were instead designed by computers and built by human hands xenobots as they are called are synthetic life forms or living robots and consist of two things skin cells and heart cells from the frog xenopus lavis after which they are named they are the first man-made organism and an entirely new
type of living system and one day scientists hope that they will help us monitor radioactivity combat pollution or even cure disease when they were first created xenobots were already testing the boundaries of how we define life but then something truly startling happened they started to spontaneously reproduce making new copies of themselves in a way that science has never observed before how is it possible for scientists to create a new type of life form and why did they in the first place how will these tiny creatures one day be of great use to us and what
can they tell us about the nature of life itself sometimes called soft robotics the field of biorobotics is a relatively new one much like classic robotics it aims to solve human problems by constructing machines but instead of using steel nuts and bolts the key raw material for biorobotics is living tissue it's a discipline that integrates biology with mechanical design bio hybrid robots are generally composed of muscle tissue either cardiac or skeletal and an artificial scaffold and the benefit of using biology in robotics is substantial biological components have unique characteristics that artificial materials can't exactly replicate
their greater flexibility enables them to move more like living organisms than machines they can also quickly and naturally respond to external stimuli some could even heal from damage or injuries artificial structures are also prone to entropy the gradual decline into disorder the crumbling of concrete the rusting of metals the breakdown of plastics but living organisms are in a constant battle against entropy they preserve their internal order by taking energy from their surroundings this quality alone could allow biobots to far surpass the useful lifetimes of even our best artificial technologies one of the earliest examples of
soft robotics is this creation made in 2014 it's composed of a plastic backbone surrounded in heart muscle tissue from a mouse by pulsing current in the liquid media at different frequencies the muscle cells are told to contract and the biohybrid is made to walk albeit in a very jerky way a year later this idea was refined this time using sea slug mussels this biohybrid was designed after a sea turtle so it can move more easily through its aquatic environment other biorobotics focus on articulation aka a robot that has arms or legs that can be used
to manipulate its environment this biohybrid is an articulated limb with muscle tissue attached to an artificial backbone by changing the voltage on the left or right side the muscles compress or contract causing this articulation that can be used to pick things up or move things around this biohybrid was inspired by a jellyfish it uses an artificial scaffold with layered heart tissue on top of that the biohybrid moves in a very similar way to a real jellyfish and more recently scientists have created a light controlled stingray it's a stingray shape made out of an artificial backbone
that is layered with rat heart muscles instead of being directly activated by electricity these muscle cells have been programmed to be activated by light this way you can drive the robot around by shining lights on either the right or left hand side but for all these machines to work outside input is needed for them to know how to behave electricity or light supplied by a human plus the artificial components can break and if used in the environment are not biodegradable and in the body not biocompatible and the biological components are being used just as an
actuator they are just providing the machine with motion as a motor would but cells can do so much more than just contract there's an entire world of innate behavior and rich biochemistry that could be utilized in cellular machines and on top of all of that the form of these biorobots all resemble existing organisms that's not necessarily a bad thing but what useful shapes and forms might exist out there that we can't even imagine we model machines based on creatures we see around us because it would be impossible to predict the behavior of some totally random
configuration that is until now enter the xenobot xenobots were born out of a goal to make an entirely biological robot with no artificial components a robot built from the ground up using only animal cells taking shape not based on any existing life form but in a totally novel configuration and it all starts with a frog embryo after a frog egg is fertilized it forms into a ball of stem cells this clump of cells looks completely uniform but in reality all of these cells have a predetermined purpose a fate of what they're meant to become the
cells on top generally become epidermis or part of the central nervous system the cells in the middle form the muscles and the cells on the bottom form the endoderm which leads to the development of organs these different sections can be disassembled into their different components and then reassembled in a new arrangement this d and reconstruction is done entirely by hand using forceps the desired sections of the embryo are removed then basically mushed back together they are then bathed in a media that causes them to stick together and they re-adhere into a sphere then the spheres
can be sculpted into new shapes using a cauterizer the formation of the bots is done by human hands but the design isn't human at all it comes instead from a complex artificial intelligence a program called voxcad creates a virtual environment complete with real-life simulations of physics like gravity friction liquid physics and surface tension and in this environment are small cubes called voxels that represent the cells of a digital xenobot different cubes represent different real-life cell identities in the beginning the researchers started with just two cell types passive like skin cells and contractile like cardiac cells
and they start with one objective for the digital xenobot to move forward the different cell cubes are then combined in a random way by the ai and then placed into an evolutionary algorithm which can evolve the digital xenobot over time creating iteration after iteration until it displays the desired behavior at first the algorithm makes completely random designs these digital bots don't exhibit any interesting behaviors beyond just sort of wiggling a bit but after many thousands of generations eventually the algorithm will produce a digital xenobot with the desired behavior moving forward the final design of the
first digital xenobot was a little blob with leg-like appendages that it could use to scuttle in a walking-like motion the scientists then make the xenobot in the lab with the same configuration sticking the correct cells together and sculpting it into the right shape and sure enough when placed in their aquatic petri dish the bots started walking and when placed in an orientation facing to the right they generally always walked to the right as hoped the ai quite accurately predicted the way that the bots would move the pink lines show the movement that the ai predicted
and the blue lines show the actual movement of the xenobots with this predictable movement the next step was to put the xenobots to the test to see if they could move through varied environments in mazes ranging from wide open fields to tubes as small as half a nanometer in diameter smaller than the diameter of a human capillary in all cases the zenobots followed the path provided by the environment traditional robots would have a lot of trouble navigating something this small but the xenobots could do so with ease soon different types of locomotion were created in
the bots including bots with small cilia that beat giving forward motion these ones like to spin in circles the scientists also noticed that if they injured the xenobots after about 10 minutes the wounds would close and the bots would heal up researchers are still working to understand the intricacies of this but it appears that self-healing is a built-in feature of these biobots where contraction at the wound site can help close the injuries propelling themselves along and healing the xenobots were already making waves in the scientific community as a revolutionary biohybrid but as all roboticists know
sometimes robots end up doing surprising things without being programmed and without any sense or communication organs the xenobots spontaneously started to work together collecting and organizing piles of debris how is such cooperation possible by mindless little bots a hint comes from a study done in 1999. these are sensorless robots each with a little scoop on its front designed simply to drive around and in their environment are many small discs the robots don't know about any other robots can't sense if they're touching anything can't tell if they're actually touching a disc but as it randomly drives
around by chance it will eventually start pushing a disc the robot can push one disc or maybe two but if it comes across a pile of disks the robot isn't strong enough to keep pushing so it's forced to reposition itself and let go inadvertently adding its disk to the pile over time therefore piles of the disks spontaneously emerge this is precisely what's happening with the xenobots they simply push particles by chance until they cannot which spontaneously leads to organized piles of the debris and even though it's a mindless and uncoordinated act it could be a
powerful tool for us one day scientists think this gathering behavior could allow such bots to collect micro plastics from ocean water or to clear plaques from arteries in the human body and this ability led scientists to think what else could the xenobots aggregate what else could they round up and make little piles out of this is where the zenobot story gets properly freaky first the scientists had the ai redesign the xenobots to optimize for collecting particles the original sphere shape as you might guess isn't so great for the collection task instead the computer suggested a
c-shape similar to pac-man which is highly efficient at collecting loose particles then the researchers added a compelling material to the xenobot's environment frog stem cells the raw material of a xenobot and as the scientists hoped the xenobots dutifully swept them up into small piles just like they did with random debris and then something remarkable happened the piles of cells turned into new xenobots there are many types of reproduction in the world of organisms from sexual to asexual from splitting to budding to birth these processes all share one common trait they all come from the parent
organism one way or another but what the xenobots did has never before been observed in living organisms it's called kinematic self-replication and has only ever been observed in certain molecules it's the act of reproducing by moving and compressing dissociated parts in the environment and although it's never been observed in cellular life forms until now it's possible it even played a role in the origin of multicellular life on earth and this ability in robotics could lead to exponential utility over time currently individual xenobots can live for 10 days in an aqueous environment without needing any outside
food source this is a good start but limits what a zenobot could do in the real world but if xenobot raw material could be continually added to the environment it could mean limitless generations of xenobots which could be a real force for good along with clearing pollution one day they could perhaps be programmed to selectively pick up and move specific cell types that we want to use in regenerative medicine aggregating the materials for a body to regrow damaged tissues researchers are now working to create xenobots that have a working memory a read write ability to
record one bit of information using a fluorescent marker that indicates if they've experienced something in their environment this type of memory could help us detect the presence of things like radioactive contamination chemical pollutants drugs or certain diseases and perhaps most importantly by understanding xenobots we start to understand the plasticity of living cells freed of their evolutionary fate cells could be capable of astounding things they can walk they can swim they can collect debris and reproduce the question is what else might they be able to do as for whether or not these bots are alive is
still a matter of great debate they are made out of living cells and can reproduce but are still very much machines our minds like to try to categorize but in reality we might need to accept that xenobots occupy a space in between both living and machine for now xenobots are simple and lack nervous systems but if future biobots are capable of emotions feelings or pain this quandary may need more serious consideration harnessing the power of biology will be the driving force behind the next century of technological developments whether it's understanding the raw ability of cells
free of their evolutionary fate or by analyzing the products of 3.8 billion years of evolution the natural world has the answers we need in our quest to beat cancer find solutions to antibiotic resistance respond to natural disasters or traverse the toughest climates imaginable our survival in the future relies on tapping in to nature's genius and in a brand new six part series on curiosity stream you can explore this cutting edge of science with the series called evolve this refreshing docu-series dives deep into the emerging world of biomimicry and whether the unique adaptations of the animal
world can truly help us to find futuristic solutions to some of our biggest problems it's one of the best series on curiosity stream it looks at mesmerizing behaviors like this water-gathering butt-in-the-air behavior from a namibian sand beetle and searches for some of earth's most venomous creatures which may hold important answers in medicine curiosity stream is a great streaming platform and now they've partnered with us to offer an incredible deal by signing up to curiosity stream you now also get a subscription to nebula nebula is a streaming platform made by me and several other educational youtube
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