What Do a Frog, a Scientist and a Stem Cell Have in Common?
Kamil Czuchrowski

What Do a Frog, a Scientist and a Stem Cell Have in Common?

Scientists build the first ever living, programmable organism from frog stem cells

Researchers from the University of Vermont and Tufts University announced last month that they have successfully developed tiny living “machines”. The team repurposed living cells, scraped from African frog Xenopus laevis embryos, and assembled them into entirely new life-forms. These millimeter-wide "xenobots" can move towards a target, perhaps pick up a miniature payload—like a medicine that needs to be carried to a specific place inside a patient—and heal themselves after being cut. This discovery is paramount as the new xenobots are not what you would consider a normal robot or a known species of animal. It’s a completely new class of artifact: a living, programmable organism.

Manufacturing reconfigurable organisms. (PNAS Journal, "A Scalable Pipeline for Reconfiguring Organisms")

Why create a new type of robots?

Typical machines are made from synthetic materials like steel, concrete, chemicals and plastic which take a long time to degrade. They also produce harmful side effects and by products (think microplastics in the oceans). We keep hearing about new and sustainable ways to clean the environment, produce energy or even food. But, they all have their drawbacks. Hydro energy can pollute water, wind energy can reduce or degrade wildlife habitats, plants and fish, and solar energy can take up valuable space. In short, there isn’t one perfect way to balance the good vs. the bad. 

Unique living systems

Living systems are considered robust in structure and function without many adverse effects on the environment. On the flip side, they also tend to be difficult to control and resist adopting to new behaviors. If we were able to quickly and endlessly change those traits we might be on the path to making a real and sustainable difference. We are far from the “I, Robot” scenario, but different methods have been employed to build and design bespoke systems. The newly discovered living robots can heal any cuts, shimmy along, pick up tiny little parcels, and once finished they simply fall into pieces and degrade and decay (forming dead skin cells) just like any other natural organisms.

The new designs were possible due to thousands and  thousands of runs of an ‘evolutionary algorithm’ testing many 3D designs of skin and heart cells inside a simulator. Only a handful of the designs were actually used for building the bots. Thanks to the heart cells and their spontaneous contractions, they act like tiny little engines making it possible for the robots to propel themselves forward or fulfill basic tasks within the simulation. They are also able to survive between 7-10 days without any additional inputs.

In the transfer from silica to vivo, a robust, stable and energy-efficient configuration of passive (epidermis; green) and contractile (cardiac; red) tissues found by the evolutionary algorithm. (PNAS, "A scalable pipeline for designing reconfigurable organisms")

If you’re interested to see how the robots are able to walk check out this article in The Guardian.

Scientists tested the bots capabilities in simple dishes of water (keeping the frog cells alive) and observed different patterns of movement.  Some tiptoed in simple straight lines while others looped in circles or grouped with others to form little schools (just like tadpoles!). Xenobots offer a step up from nanobots as they can be remodeled, changed and discarded without any adverse effect. This discovery doesn’t directly affect Drug Discovery, but it could have an impact on how scientists deliver specific drugs to a specific place in the body. As such, they might be an alternative to flexible nanobots made from synthetic materials. 

Three Laws of Robotics

While some people have already raised ethical and safety concerns, there is still time before any of the Asimov’s Laws need to be implemented. The implications of rapid technological change and complex biological manipulations lead to some interesting discoveries.  Future plans include using mammalian cells to allow xenobots to survive on dry land or be selected for cognitive behaviors. In an article in The Guardian, Michael Levin (co-leader on the study and director of the Centre for Regenerative and Developmental Biology at Tufts) says that “the aim is to understand the software of life. If you think about birth defects, cancer, age-related diseases, all of these things could be solved if we knew how to make biological structures, to have ultimate control over growth and form.”

So when do we start thinking about them in terms of beings, with interests that need to be protected? Some sources, however unconfirmed, have already suggested that all living creatures have interests that should be given moral consideration, which raises the question: are xenobots living creatures or machines?

If these xenobots advance it could be the ethical questions that vex us the most.

Full research article, A scalable pipeline for designing reconfigurable organisms, is available at Proceedings of the National Academy of Sciences of the United States of America, and you can see the bots in action at: https://youtu.be/aQRBCCjaYGE .