Written by: Nathan Handjojo

In a new field of cutting-edge biotechnology, a groundbreaking fusion of biology and robotics has emerged, pushing the boundaries of what we conceive as living organisms and machines. Enter the xenobots – a revolutionary class of programmable, living robots created from organic materials. These microscopic marvels, named after the African clawed frog Xenopus laevis from which their cells are derived, represent a pioneering leap in the field of synthetic biology. With capabilities ranging from self-repair to autonomous movement, xenobots signify a shift in how we engineer and interact with artificial lifeforms.

Unlocking the Potential of Xenobots

Xenobots are not typical robots; they are built from the ground up, starting with stem cells harvested from frog embryos. These cells are then carefully reprogrammed and assembled into specific configurations, allowing researchers to design xenobots tailored for various tasks. Unlike traditional robots made from rigid materials like metal or plastic, xenobots are soft-bodied and composed entirely of living cells, granting them unique advantages in navigating complex environments and interacting with biological systems.

These tiny organisms are capable of remarkable feats. Through computational modeling and experimental validation, scientists have demonstrated that xenobots can exhibit collective behavior, such as flocking and swarming, akin to certain species of living organisms. These self-powered living robots can rapidly swim through their environment, can be modified to record experience, and can work in groups to collect small objects in their vicinity. This new platform provides a faster way to manufacture large numbers of living robots, which can be used to study aspects of self-assembly, swarm behavior, and synthetic bioengineering, as well as provide versatile, soft-body living machines with practical applications in biomedicine. 

Figure 1

Picture of Xenobots Kinematically Replicating 

Source: Proceedings of the National Academy of Sciences

How They are Made

Computers model the dynamics of the biological building blocks (skin and heart muscle) and use them like LEGO bricks to build different organism anatomies. The behavior of each designed anatomy is simulated in a physics-based virtual environment and assigned a performance score (e.g. distance traveled). An evolutionary algorithm starts with a population of randomly assembled designs, then iteratively deletes the worst ones and replaces them with randomly mutated copies of the better ones. It is the survival of the fittest, inside the computer. The fittest designs in virtual reality are then selected to be built out of real biological tissues. Figure 2 Shows some examples of the designs and how they were fabricated in real life.

The behavior of organisms was traced and compared with the virtual design. To determine whether the organisms’ movement was a result of chance or due to the design’s evolved geometry and tissue placement, geometry and tissue distribution were altered by rotating the design 180° about its transverse plane (flipping it over onto its “back”). The shape and tissue placement of the built organism were compared using computer vision.

Figure 2

AI methods automatically design diverse candidate lifeforms in simulation (top row) to perform some desired function, and transferable designs are then created using a cell-based construction toolkit to realize living systems (bottom row) with the predicted behaviors.

Source: https://cdorgs.github.io/

Biomedical Applications

In the realm of biomedicine, xenobots offer a plethora of possibilities, from targeted drug delivery to tissue regeneration. Their ability to self-repair and adapt to physiological cues holds immense promise for revolutionizing medical interventions. Xenobots represent a groundbreaking tool for precision medicine, capable of delivering therapeutic payloads to specific anatomical sites and facilitating tissue regeneration. Their biocompatibility and biodegradability minimize adverse effects, positioning them as ideal candidates for biomedical applications. Furthermore, their ability to self-repair and adapt to changing conditions makes them invaluable for applications in drug delivery, environmental remediation, and even medical procedures within the human body.

Ethical Concerns

As with any emerging technology, developing and deploying xenobots raises important ethical considerations. Issues such as autonomy, safety, and environmental impact must be carefully addressed to ensure that xenobots are used responsibly and ethically. The harvesting of frog embryos and reprogramming them also pose another ethical concern with genetically modifying a living being. Ethical considerations play a crucial role in advancing xenobot technology, requiring careful thought and oversight. Researchers and policymakers must work collaboratively to establish guidelines and regulations that govern the ethical development and use of xenobots, balancing scientific progress with societal values and concerns.
While it seems unlikely that AI would autonomously seek to cause harm through designing organisms, the risk of unintended consequences remains a significant consideration. Thus, human oversight and verification must be incorporated into the creation and deployment of computer-designed organisms (CDOs), including xenobots, to mitigate any potential risks. One pressing dilemma is whether someone could program AI to design weaponized CDOs. Theoretically, this is possible. However, the current difficulty in achieving this suggests that the challenge is comparable to that faced by a skilled biologist with malicious intent. Nevertheless, as AI technology advances and becomes more sophisticated, the need for robust regulation to prevent misuse becomes increasingly apparent. Despite this concern, it is crucial to recognize that the likelihood of harmful outcomes from xenobots is considerably smaller than the risks posed by existing technologies in virology, bacteriology, and genome editing.

Conclusion

Xenobots represent a promising frontier in the convergence of biology and robotics, offering unprecedented opportunities for scientific exploration and technological innovation. As researchers learn more about cellular cooperation and the full potential of xenobots, the possibilities for applications in medicine, environmental science, and beyond are limitless. However, careful consideration of ethical implications and responsible governance is crucial to ensure the safe advancement of this technology.

References

Blackiston, D., Lederer, E., Kriegman, S., Garnier, S., Bongard, J., & Levin, M. (2020). Living Robot Swarms [Review of Living Robot Swarms]. LRSwarms. https://livingrobotswarms.github.io/

Kriegman, S., Blackiston, D., Levin, M., & Bongard, J. (2020). Kinematically Replicating Organisms. KROs. https://krorgs.github.io/

Kriegman, S., Blackiston, D., Levin, M., & Bongard, J. (2021). Kinematic self-replication in reconfigurable organisms. Proceedings of the National Academy of Sciences, 118(49). https://doi.org/10.1073/pnas.2112672118

Kriegman, S., Blackiston, D., Levin, M., & Bongard, J. (2021). Xenobots. Xenobots. https://xenobots.github.io/