Produce like no other
Scientists argue over the reproduction of biological robots
On Monday, a group of scientists from the Universities of Vermont, Tufts and Harvard, which unveiled the world's first biological robots last year, said they are capable of self-replicating. Moreover, in a way unique for animals and plants. However, while the creators of biorobots call their discovery a breakthrough, other scientists consider the study too publicized, and the conclusions far-fetched.
In early 2020, scientists from Tufts University, Harvard and the University of Vermont published a research paper on the creation of the world's first biological robots. Based on the stem cells of the African clawed frog (Xenopus laevis) embryos, scientists began to form tiny bodies called xenobots. These are miniature creatures (less than 1 mm in size), whose shape was determined and inferred by artificial intelligence. As a result, several of the most successful configurations of the bodies of biorobots were selected, which allowed them to move, carry a microscopic load on themselves or push it in front of them.
The value of this discovery, scientists said, lies in the fact that miniature biorobots can be programmed to perform certain useful actions.
For example, it is likely that they will be effective in cleaning the oceans of microscopic plastic particles, or they can be used to clean the walls of blood vessels in humans and to deliver drugs to the internal organs of humans.
Nothing is known about the practical use of xenobots yet - the technology for adjusting their work is still at a very early stage. But two years of observations led to the discovery of scientists: xenobots can reproduce. But they do it not like frogs, whose biorobots are stem cells. Their mode of reproduction is generally not characteristic of animals or plants.
As scientists have found, xenobots are capable of producing offspring by creating copies of themselves. Each xenobot circles in space, picking up and collecting hundreds of individual cells in its mouth. Then the biorobot "spits out" the accumulated mass, which is already a single whole. After a few days, this mass of cells becomes a new full-fledged xenobot.
Such a behavior model was previously found only in individual molecules, but has never been observed in full-fledged cells, and even more so in living organisms.
However, the pioneering scientists had to work hard so that the xenobots could go through at least a few cycles of offspring. The fact is that under normal conditions, these tiny creatures are only able to reproduce smaller copies of themselves. And after a few generations, “children” are born, unable to move or even create new offspring. As a result, after seven to ten days, their charge of biological energy dries up, they decompose, and the family tree breaks off.
In addition, xenobots of a natural form extremely rarely engaged in the creation of offspring at all and only under certain conditions, scientists say. Therefore, they decided to improve this process: with the help of artificial intelligence, the most effective form of xenobot for collecting free cells was found. This turned out to be a C-shape, somewhat reminiscent of Pacman from the famous arcade game.
“If we figure out how to get groups of cells to do what we want them to do, they will ultimately become a tool for regenerative medicine and treat traumatic injury, birth defects, and cancer and aging,” the study authors say.
In addition, in their opinion, the study of the reproduction process of xenobots can bring the scientific community closer to solving the mystery of the origin of life on Earth - it is likely that the first molecules on our planet reproduced in this way.
But not everyone in the scientific community considers the discovery to be a scientific breakthrough. For example, the scientific editor of Ars Technica, John Timmer, who spent many years doing biological research at the University of California at Berkeley and Cornell University, notes that the excitement around the research looks exaggerated, and the very statement about the ability of xenobots to reproduce as a "form of endless reproduction" - just false.
As noted by Mr. Timmer, the discovery of scientists has two problems at once. First, xenobots themselves are capable of producing only one generation of offspring. The brainchild of an ordinary xenobot, smaller than the parent organism. Therefore, it rotates along a much smaller diameter, being unable to collect enough cells to create a new xenobot.
As a result, the entire family tree of xenobots would fit into two generations.
Secondly, even the intervention of scientists in the natural process did not allow to achieve endless reproduction of offspring. They literally cut out "Pacman" from biorobots in order to increase the efficiency of their reproduction. But even this was not enough: the xenobots 'cubs' obtained at the first stage were too small, and therefore, together with their parental organisms, they had to be transferred to a new biological environment rich in individual cells that could serve as building materials for xenobots. But even this helped extend the life cycle of biological robots by just three generations - nothing to do with endless reproduction.
Mr. Timmer notes that such a replication process has never really occurred in living organisms. Simply because in nature, hardly anyone would offer living organisms two Petri dishes, completely filled with individual cells, only so that the organisms could make offspring for themselves.