January 24, 2020, by Brigitte Nerlich

Xenobots-Xenowhats? Living machines and zombie metaphors

The other day a colleague asked me what I was up to. I said, ‘I am starting to think about xenobots’. ‘Xeno-whats?’ he asked?  I muttered something like ‘you know as in ‘xeno-transplantation’, when another colleague butted in and asked ‘like Xenogenesis?’. ‘Xeno-what?’ I asked.

It turns out there is sci-fi trilogy by Octavia E. Butler written in the 1980s with that title. I should have known that! If a younger person had been present, they might have said “ah, like ultrabots”, referring to a 1993 video game or similar where xenobots operate. I myself was thinking back to my time with ‘nanobots’…

Strangely, none of these cultural or scientific references came up, apart from briefly nanobots, when I started to look at how xenobots were talked about in the popular media.

What got me to think about xenobots? A while ago I had ripped a page out of The Guardian and put it aside for future investigation. On it was an article by Ian Sample with the title ‘It’s alive’ – scientists use frog cells to create world’s first living machines” (14 January 2019). For some reason that page disappeared under a pile of other papers. Now, after some twitter-sightings of xenobots, I pulled it out again, and thought, hmmm, I must look into this.

The images that illustrated the article are intriguing, showing a sort of three-dimensional block structure made of ‘bricks’ with some of the bricks or ‘cells’ coloured in different shades of red or green, some with protruding ‘feet’. Alongside these brick-assemblages are pictures of more typical cell-like structures, imitating the shapes of the brick ones, to some extent. Intriguing. What was this all about? 

Xenobots make an appearance 

On 13 January Sam Kriegman, Douglas Blackiston, Michael Levin, and Josh Bongard published an article in the Proceedings of the National Academy of Sciences (PNAS) entitled innocently enough: “A scalable pipeline for designing reconfigurable organisms”. Even the abstract doesn’t give anything away, really, apart from the fact that it talks about living systems and biological machines. But that is quite common nowadays in the age of synthetic biology. So, what about the xenobots, a term not used in the paper, but probably introduced to the world in the interviews given by the scientists?

These are strange and artificial life forms. As quoted in many articles covering the findings reported in the PNAS paper: “These are novel living machines,” explains Joshua Bongard, a computer scientist and robotics expert at the University of Vermont. ‘They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.'”

How did they come about? These living machines emerged from a combination of computation (AI, algorithms, especially evolutionary algorithms) and biological assembly and ‘sculpting’ (see this official video here). As nicely summarised by Simon Chandler for Forbes 

“First, the scientists at Vermont simulated possible configurations of individual biological cells on a supercomputer. They used what’s called an evolutionary algorithm to test thousands of possibilities and find the best candidates, ‘best’ in terms of the known biophysics of biological cells, which in this case were frog cells. /Once found, re-tested and refined, researchers at Tufts then used the simulated models to construct the xenobots. They did this by taking stem cells from the embryos of African frogs and joining them using microscopic forceps and electrodes, building a living robot on the basis of the blueprints they’d received.” (We’ll get to the blueprints later)

Xenobots – the name 

I am not sure who exactly coined the term ‘xenobot’, but I was quite surprised by its etymology. As mentioned in many articles about this paper, xenobots were named after the African clawed frog (Xenopus laevis) from which the scientists took their stem cells. The term Xenopus, in turn, was coined by Johann Georg Wagler in 1827 – and derived from ancient Greek ξένος (xénos, “foreign, strange”) + πούς (poús, “foot”). Whatever the real etymology, these bots are strange (xeno…); as one article said: neither beasts not bots 

Xenobots in scientific and cultural context

Xenobots are the latest in a series of breakthroughs in biology over the last twenty years or so which have fascinated me in terms of how they are talked about, how they are imagined and what hopes and fears they evoke.

These new developments are: cloning, stem cell research, regenerative medicine, tissue engineering, systems biology, synthetic biology, bio-engineering, computational biology, organoids and also nanotechnology. I have written about all of that. Xenobots relate to all of these fields and issues, but they also have things in common with stuff I haven’t written about, namely, robotics, algorithms and AI, evolutionary algorithms, evolutionary robotics, complexity, emergency, self-assembly, self-replication and so on. So, xenobots have their fingers or rather feet in many pies. What does that mean for how they might be perceived by the general public who may well ask like many: ‘Xeno-whats?’ 

I can of course not ask the general public about xenobots for this blog post. So I did the next best thing, as I always do, and looked at how they are talked about in the media. For this post, which is NOT a scientific article, I quickly scanned tweets about xenobots and/or living machines, looked at Google News and also some English Language News items on the news database Nexis (searched up to 22 January).

It soon became clear that most of these items repeated each other and reproduced what the authors of the PNAS article had told them in interviews and the official video. I also got the feeling that there was no general outcry – probably because we, the general public, have so many other things to be outraged about and/or because biological advances that once would have seemed spectacular have now become the norm. As one tweet asked: “So why is the news on the xenobots not a hot topic?”

Of course, some people talked about Playing God and about Frankenstein. At least one person mentioned H. G. Wells’ The Island of Dr Moreau and another the golem, and, more creatively some people likened the bots to The Blob (that featured in a 1958 film) or Tetris. Some, fearing that the blob bot would self-replicate also conjured up the old spectre of grey goo from nano-times, i.e. the fear of nanobot replicators run amok.

There are those that fear Frankenstein: “Tiny ‘xenobots’ assembled from cells promise advances from drug delivery to toxic waste clean-up – no no no Frankenstein”, “Es un golem de carne, como el monstruo del doctor Frankenstein”, “In true Frankenstein fashion, researchers create living machines from frog embryos”, “These ghastly Frankenstein creations were made from cells scraped from frog embryos. Next will come human xenobots”.

Some highlight that the research into xenobots was partially funded by DARPA: “funded courtesy of the DOD a/k/a the American Taxpayer nothing to see here folks – move along – Frankenstein was just a fable”.  

One tweet quoted a passage from an RT article: “This is an astonishing leap forward in the game of playing God. But who exactly is the Dr Frankenstein to these xenobot monsters? Unnervingly, their specific shapes…were designed not by the clever scientists, but rather by a supercomputer.”

There are also those that don’t fear Frankenstein: “quite a way short of Frankenstein, but on the right path” and more strongly “there’s nothing Frankenstein here” (this was repeated in many commentaries – a quote from Tara Deans, a biological engineer and assistant professor at the University of Utah who did not participate in the new study).

It should be stressed that these ‘monsters’ are fully biodegradable! But in a sense Frankenstein’s ‘monster’ was too…. One of the researchers tried to pre-empt the monstrification of xenobots by calling them ‘walking caviar’… an image that sort of sticks in the mind. (And we’ll get back to that, too)

Building blocks of life, blueprints and programmes 

But what did the xenobots look like? Many of the articles are illustrated with images and videos that show a row of block assemblies and a row of cell assemblies. For example, an article in Gizmodo magazine by George Dvorsky, entitled “Made entirely from cells, these adorable ‘xenobots’ are practically alive”, has an illustration subtitled “Left: A xenobot blueprint produced by the evolutionary algorithm, in which green shows skin cells and red shows heart muscle cells. Right: the “living” xenobot inspired by the computer’s design.” 

Two metaphors pervade the (visual) discourse about xenobots: ‘building block of life’ and ‘blueprint’. Both of these, but blueprint in particular, are nowadays regarded as outdated and misleading, and rightly so. They don’t capture the dynamics and complexity of genomes in particular and biological processes in general.

But what about the use of ‘blueprint’ in this context? Are we dealing with metaphors at all?? When you read this (in The Scientist), you start to have doubts:  

Bongard shared several of the designs of simple, cell-based robots that his algorithm had created with Levin and his team. /Bongard’s designs were only theoretical, but to his surprise, a microsurgery expert and staff scientist in Levin’s lab, Douglas Blackiston, took one of the plans and actually built it using frog embryo cells.  /Up until then, says Bongard, ‘we didn’t realize that they were able to actually take computer-designed blueprints and build a design in reality. That really shifted the focus of the project.’” 

Furthermore, xenobots derive from a computer programme and they are programmable themselvesThey were created just ten years after Craig Venter created his first synthetic cell and said: “It’s the first self-replicating cell on the planet that’s parent is a computer”. I always used this as an example of a metaphor. But was it? It certainly is no longer, I believe. 

Xenobots, public debate and the paucity of public imagination 

This new collaboration between computersbiology and design is only just starting. So, it is good that the scientists coming up with this ‘proof of concept’ engage in what was formerly called ‘upstream engagement’. As one of the scientists, Sam Kriegman, quoted in The Guardian article, said: “What’s important to me is that this is public, so we can have a discussion as a society and policymakers can decide what is the best course of action”.  

In this public discussion we find the usual tropes about Frankenstein’s monster and the usual fears about using xenobots being used as bioweapons, but so far this seems to be the exception rather than the rule. This brings us back to ‘walking caviar’ and another good quote from Sam Kriegman: 

“For the time being, Kriegman says these living machines are little more than ‘walking caviar,’ but that he agrees it’s important to begin having those conversations as soon as possible with research like this.” This is exactly what science society scholars have always called for. 

Science has come a long way from frogs’ legs (Galvani) and frogs’ eggs (Briggs and King’s 1952 early cloning or nuclear transplantation experimentsalso published in PNAS) to xenobots, but has popular imagination done the same? Galvani inspired Mary Shelley who penned Frankenstein in 1818, a book(title) that has inspired popular debate about advances in the biological sciences ever since. Do we need some other ways to think about them in the 21st century? What could they be?  

There will be a blog post about that in the future! 

Stuff to read on all this by Philip Ball: 

Two books, one ‘Unnatural: The heretical idea of making people‘ and one ‘How to grow a human‘ and one article on Frankenstein in particular.

And keep your eyes peeled for a forthcoming article that will tell readers what xenobots are really about!

Image: Xenopus laevis, Wikimedia commons 

Posted in biotechnologyLanguageMetaphorspublic engagement with scienceScienceScience Communicationsynthetic biology