US scientists have managed to create living organisms out of skin cells and, in the project’s newest development, they have managed to self-replicate.
The living robots are named ‘xenobots’ after the African clawed frogs (Xenopus laevis), whose skin cells facilitated their creation.
This was a collaboration between a team of scientists led by Joshua Bongard, a professor of computer science at the University of Vermont, and Michael Levin, Vannevar Bush Professor of Biology and director of the Allen Discovery Center at Tufts.
Robots, as we know them, are created from metal or porcelain, meaning that these materials are prone to deterioration over time as well as system malfunctions and hacking. Breaking the mould, Xenobots were created from biocompatible materials through bioengineering. This also means that, unlike their non-organic predecessors, they are biodegradable, (more) self-reliant, and environmentally friendly.
Though the original organisms were first publicly unveiled in 2020, the initial generation was unable to replicate. This recent breakthrough means that scientists no longer have to go through the laborious process of creating these microorganisms by hand. Thousands of xenobots will be able to arise out of self-reproduction, allowing more complex tasks to be carried out.
With an impressive range of feats, the xenobots are able to swim through liquid, team up to collect particles into piles, heal their own injuries, navigate through tubes, and store information from their experiences.
Scientists at the University of Vermont used their Deep Green supercomputer cluster and started with computer simulations, modelling different shapes and cellular arrangements, which aided in deciding the best possible configuration for an artificially-assembled living organism. Paired with the guide of intended specific behaviours, failed designs virtually ‘died’, whilst successful ones ‘lived’. The evolutionary algorithm scanned billions of designs, simulating many generations over and over, and the optimal design was found to be a semi-torus – resembling an open-mouthed Pac-Man.
In an interview with CNN, Bongard explained:
‘The AI didn’t program these machines in the way we usually think about writing code. It shaped and sculpted and came up with this Pac-Man shape. The shape is, in essence, the program. The shape influences how the xenobots behave to amplify this incredibly surprising process’.
This design was then passed on to the team at Tufts University, who dissected frog embryos to harvest embryonic skin cells. These cells naturally clumped up into a ball of epidermis when they were placed in a saline solution, and from this, the scientists were able to utilise microsurgical tools to physically shape the ball into the final design through masterfully squishing and cutting into it.
Following this, cardiac progenitor cells, which eventually develop into heart muscle, were layered throughout the cell in accordance with the design. This, paired with the cilia – or hair-like structures on the surface of the organism – allows the organisms to become mobile. These movements mimicked the ones shown in the simulations, successfully enabling the xenobots to push debris around and join together.
When stem cells were added to the dish, the xenobots were able to collect them, gathering them into clusters in their mouth. After a few days, these clusters turned into fully-formed xenobots, with the ability to reproduce at least five generations.
This method of reproduction is unknown to any other natural living organism, as is more akin to the way non-biological molecules replicate. Though the process may sound complicated, lead scientist Levin explained in terms of computer technology:
‘The analogy that I use is that of hardware and software. What the genetics does is provide the hardware. It tells every cell exactly what components it gets to have. That biological hardware has remarkable versatility—we can assemble groups of cells to solve the problem of forming a functional creature in different ways’.
In this analogy, the software is parallel to how the cells are arranged. Levin continues:
‘[Evolution has programmed this] for millions of years, and as a result, a frog became the default ‘device.’ But those cells can be recombined and reprogrammed to create a new organism—the xenobot, and that doesn’t need millions of years of selection for xenobot functionality to learn how to swim, heal, record information, and replicate in a novel way. We put the cells together and the tissue can literally figure that out in 48 hours—the length of time it takes the bot to form.’
Furthermore, each type of cell has distinct features and can be recombined to create organisms with different capabilities and behaviour. Senior scientist Blackiston says these cells can come from different species, and the hope is that ‘[eventually] we would like to have a library of modules where you go to the freezer, pull out the features you want, hook them together and you have a designer organism’.
Though they do not have any practical uses yet, this technology has the potential to alter many fields.
In environmental health, these xenobots could be used to collect the microplastics polluting our oceans, as well as radioactive waste.
If mammalian cells are used, these xenobots could also be compatible with the human body, delivering medicine, and even regenerating or healing damaged body parts.
The researchers’ website states:
‘If we could make 3D biological form on demand, we could repair birth defects, reprogram tumors into normal tissue, regenerate after traumatic injury or degenerative disease, and defeat aging, [which could produce] a massive impact on regenerative medicine.’
Nanotechnology such as this can be very hostile, as we do not know the full capabilities of regenerating, reproducing lab-developed living creatures.
A recent article stated that the idea of the replicating robot can be traced back to mathematician John Von Neumann, who in 1966 highlighted the ‘self-reproducing automata’. Additionally, Engineer Eric Drexler, who coined ‘nanotechnology’, also warned of miniature, replicating machines consuming their surroundings, creating a ‘grey sludge’ out of themselves. Philosopher Francis Bacon highlighted the dangers of scientific progress, saying that some research is simply too dangerous to pursue, which is pertinent because many feel that this may be the case for xenobots.
Though we do not know where these experiments may lead in the future, tight regulations must nevertheless be kept in place. The use of xenobots and similar technology is banned under the United Nations’ Biological Weapons Conventions as well as the 1925 Geneva Protocol and Chemical Weapons Convention.
Rest assured, scientists guarantee that the experiment is entirely lab-controlled, and may easily be extinguished. These organisms have their own food sources of lipid and protein, and live for a very short period of time. The experiment is also regulated by ethics experts.
Xenobots will without a doubt affect life as we know it in the coming decades – this research has opened up a host of possibilities in the fields of AI and molecular biology. This fusion of technology and nature will inspire many after it, which is why it is important to monitor the project and lay out regulatory foundations before artificial life can ever cause any harm.
About the Author: Shadine Taufik
Shadine Taufik is a contributing Features writer with expertise in digital sociology and culture, philosophy of technology, and computational creativity.
