Team builds the 1st living robots

The scientists call them “xenobots.” They are tiny living robots assembled from the cells of frogs. Their creators promise advances from drug delivery to toxic waste clean-up.

Scientists from the University of Vermont (UVM) and Tufts University in Massachusetts said on January 13, 2020, that they’ve now assembled living cells into entirely new life-forms. They call them living robots, or xenobots for the frog species from whose cells the little robots sprang. The scientists describe them as tiny blobs, submillimeter in size (a millimeter is about 1/25th of an inch, so these little blobs are smaller than that). The blobs contain between 500 and 1,000 cells. They can heal themselves after being cut. The blobs have been able to scoot across a petri dish, self-organize, and even transport minute payloads. Maybe, eventually, they’ll be able to carry a medicine to a specific place inside a human body, scrape plaque from arteries, search out radioactive contamination, or gather plastic pollution in Earth’s oceans.

And, yes, the scientists do acknowledge possible ethical issues. More about that below.

Joshua Bongard, a computer scientist and robotics expert at the University of Vermont who co-led the new research, said in a statement:

These are novel living machines. They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism …

You look at the cells we’ve been building our xenobots with, and, genomically, they’re frogs. It’s 100% frog DNA — but these are not frogs. Then you ask, well, what else are these cells capable of building?

The results of the new research were published January 13 in the Proceedings of the National Academy of Sciences.

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A little square blob with four 'feet', seen from below.

A manufactured quadruped (4-footed) organism, 650-750 microns in diameter (a micron is a millionth of a meter). The scientists described this creature (if we can call it a creature) as “a bit smaller than a pinhead.” Image via Douglas Blackiston/ Tufts University/ University of Vermont.

In their published paper, these scientists wrote:

Most technologies are made from steel, concrete, chemicals, and plastics, which degrade over time and can produce harmful ecological and health side effects. It would thus be useful to build technologies using self-renewing and biocompatible materials, of which the ideal candidates are living systems themselves. Thus, we here present a method that designs completely biological machines from the ground up: computers automatically design new machines in simulation, and the best designs are then built by combining together different biological tissues. This suggests others may use this approach to design a variety of living machines to safely deliver drugs inside the human body, help with environmental remediation, or further broaden our understanding of the diverse forms and functions life may adopt.

The new creatures were designed on a supercomputer at UVM, and then assembled and tested by biologists at Tufts University. The scientists’ statement described their process this way:

With months of processing time on the Deep Green supercomputer cluster at UVM’s Vermont Advanced Computing Core, the team – including lead author and doctoral student Sam Kriegman of UVM [@Kriegmerica on Twitter] — used an evolutionary algorithm to create thousands of candidate designs for the new life-forms. Attempting to achieve a task assigned by the scientists – like locomotion in one direction – the computer would, over and over, reassemble a few hundred simulated cells into myriad forms and body shapes. As the programs ran – driven by basic rules about the biophysics of what single frog skin and cardiac cells can do – the more successful simulated organisms were kept and refined, while failed designs were tossed out. After a hundred independent runs of the algorithm, the most promising designs were selected for testing.

Then the team at Tufts, led by Michael Levin and with key work by microsurgeon Douglas Blackiston — transferred the in-silico designs into life. First they gathered stem cells, harvested from embryos of African frogs, the species Xenopus laevis [African clawed frogs; hence the name “xenobots.”]

These were separated into single cells and left to incubate. Then, using tiny forceps and an even tinier electrode, the cells were cut and joined under a microscope into a close approximation of the designs specified by the computer.

Assembled into body forms never seen in nature, the cells began to work together. The skin cells formed a more passive architecture, while the once-random contractions of heart muscle cells were put to work creating ordered forward motion as guided by the computer’s design, and aided by spontaneous self-organizing patterns – allowing the robots to move on their own.

These reconfigurable organisms were shown to be able move in a coherent fashion – and explore their watery environment for days or weeks, powered by embryonic energy stores. Turned over, however, they failed, like beetles flipped on their backs.

Later tests showed that groups of xenobots would move around in circles, pushing pellets into a central location – spontaneously and collectively. Others were built with a hole through the center to reduce drag. In simulated versions of these, the scientists were able to repurpose this hole as a pouch to successfully carry an object.

Wow … yes?

The scientists said they see this work as part of a bigger picture. And they acknowledged that some may fear the implications of rapid technological change and complex biological manipulations. Levin commented:

That fear is not unreasonable. When we start to mess around with complex systems that we don’t understand, we’re going to get unintended consequences.

However, he said:

If humanity is going to survive into the future, we need to better understand how complex properties, somehow, emerge from simple rules.

He said much of science is focused on:

… controlling the low-level rules. We also need to understand the high-level rules.

I think it’s an absolute necessity for society going forward to get a better handle on systems where the outcome is very complex. A first step towards doing that is to explore: how do living systems decide what an overall behavior should be and how do we manipulate the pieces to get the behaviors we want?

In other words, he said:

… this study is a direct contribution to getting a handle on what people are afraid of, which is unintended consequences.

Bongard added:

There’s all of this innate creativity in life. We want to understand that more deeply – and how we can direct and push it toward new forms.

Red and green blocks stacked into a partial cube and red and green cells in a blob.

On the left, the anatomical blueprint for a computer-designed organism, discovered on a UVM supercomputer. On the right, the living organism, built entirely from frog skin (green) and heart muscle (red) cells. The background displays traces carved by a swarm of these new-to-nature organisms as they move through a field of particulate matter. Image via Sam Kriegman/ UVM.

Bottom line: Scientists said in early January 2020 that they’ve created the first living robots, or “xenobots,” assembled from the cells of frogs. Their creators promise advances from drug delivery to toxic waste clean-up.

Source: A scalable pipeline for designing reconfigurable organisms

Via UVM

Deborah Byrd