September 28, 2020

First created “living machines” with animal cells | Science

Four young American scientists have created “living machines” for the first time, made with animal cells and capable of carrying out very simple tasks. Researchers, funded by the US Department of Defense, believe that their “reprogrammable organisms” could serve in the still too distant future for medical applications – such as tumor detection, artery plaque removal and smart delivery. of drugs inside the human body — and even for operations of environmental restoration of contaminated sites.

The authors of these living machines are two biologists, Michael Levin Y Douglas Blackiston, and two robotics experts, Josh Bongard Y Sam Kriegman. Researchers have employed as bricks two types of cells the african nail frog: the cells of your heart (contractile) and those of your skin (more passive). For months, scientists have used a supercomputer to simulate thousands of cell aggregates in different ways and try to predict their behavior. The most promising designs were carried out. The main result is a half millimeter biological machine, with a few hundred cells, capable of moving in a direction determined by scientists (click here to see how it works).

“It seems that these biobots they are a third class of animated matter: they are not robots nor are they strictly organisms. I think these biobots they will force biologists and philosophers to rethink our definitions of life and what a machine is. In the future, should computer-designed organisms have the same rights as naturally evolved people and animals? ”Asks Josh Bongard of the University of Vermont.

Michael Levin recognizes that his creatures induce many questions. The biobots they are made up of frog cells, but neither have a frog shape nor act like a frog. The biologist believes that these new organisms will serve to understand great rules of life hitherto invisible. He explains with an example: no ant has the plane of the future anthill, but all cooperate to make one. How should the ants be genetically modified to build an anthill with two entrances instead of one? Scientists have no idea.

“The big question here is: How do cells cooperate to build complex and functional bodies? How do they know what they have to build? What signals do they exchange with each other? ”Reflects Levin, from Tufts University, near Boston. “Once we discover how to incite cells to build specific structures, we will not only have a huge impact on regenerative medicine – building parts of the body or inducing their regeneration – but we can use these same principles to improve robotics, systems of communication and, perhaps, artificial intelligence platforms, ”calculates Levin.

“We show a scalable model to create new functional ways of life,” say the authors

Their biobots, made with hundreds of frog cells, are just a proof of concept. “We show a scalable model to create new functional ways of life,” the authors point out in their research, published Monday. in the specialized magazine PNAS. “If we manage to automate the manufacture of the designs by computer, we could conceive huge swarms of biobots. And these might even be able to unite in ever larger sizes. We could have very large biomachines in the future, ”says Bongard as a hypothesis. His team has already done simulations of up to 270,000 cells. A human body has about 30 billion.

The authors draw a future in which “live systems tailored for a wide range of functions” would be made. In their laboratory they have already designed a biobot with a hole in the center that, according to scientists, could be used as a pocket in which to transport or neutralize toxic substances. Supercomputer simulations also predict that, if several of these biomarkers come together, they would move spontaneously in circles, pushing whatever they found in their path to a central point. “Perhaps, in the future, large swarms of biobots, so that they gathered the microplastics in large clusters that could be collected by ships. In the end, like the biobots they are 100% biodegradable, they would become food for marine life, ”says Bongard.

American scientists Sam Kriegman, Douglas Blackiston, Michael Levin and Josh Bongard.

American scientists Sam Kriegman, Douglas Blackiston, Michael Levin and Josh Bongard.

“Other swarms could find small amounts of heavy metals in contaminated soils. And, if it is possible to make them of a sufficiently small size, the biobots they could float in the air and collect polluting particles, ”continues the robotics expert.

The biologist and physicist Ricard Solé applauds the new work, “stimulating and groundbreaking”, but stresses that some of the applications imagined by the authors “are still light years away.” Solé, from Pompeu Fabra University in Barcelona, ​​is an expert in complex systems, such as the collective intelligence of ants. “Levin’s team has made an important leap in synthetic biology, but those miniorganisms will need sensors to be able to do complex things. Adding those sensors will be the qualitative leap that will have to be taken in the future, ”says Solé.

“It’s hard to know now if this technology could have unwanted consequences or how someone could abuse it,” says researcher Josh Bongard

Chemistry Berta Esteban Fernández de Ávila He has been developing microrrobots for five years at the University of California, San Diego, sometimes combining them with living cells, as sperm. In his opinion, the strategy of Levin’s team has “many possibilities”, especially in applications such as microsurgery within the human body. “Regardless of the toxicity of the cells, we should ensure a way to inactivate them after performing the desired function. To give an example, sometimes we apply microrrobots in the stomach and take advantage of the acidity of the gastric fluid itself to deactivate them, ”warns the researcher.

Levin explains that his biobots They don’t multiply. “Basically, they stay as they are and dissolve in a week,” he says. However, his research does raise the possibility of adding to cells the ability to reproduce. “It would be a risky road. However, it may end up being one of the best routes to address the important ecological challenges posed by climate change, ”says Bongard.

“It’s hard to know now if this technology could have unwanted consequences or how someone could abuse it. But we believe that if this technology matures, we may need regulation. It is already happening with artificial intelligence and robotics, which for a long time were unregulated, ”says Bongard.


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