To be alive or to be a machine, that is the question – 03/03/2022 – Basic Sciences

Usually the first step in assembling a machine is design: how we want the machine to look, and where each part should go. If the project is based on an organism, the focus will be on imitating the function of that organism. Inspired by the flight of birds, we invented airplanes. We are interested in the power of horse movement, we make wild chariots. Out of curiosity about the brain’s memory and ability to think, we made computers. Our need to plan stems from the fact that computers, cars, and planes do not assemble themselves.

However, birds, horses, and brains do not need human planning to exist. This observation suggests a new paradigm for building technology: self-assembly and self-innovation. The wings of a bird, for example, are grouped, with the development of the exact shape of the bird’s flight without a human design foreshadowing the arrangement of bones, muscles and feathers. The ability to fly is also an example of self-innovation, since the first single-celled organisms on Earth did not have the physiological structures to do so. Mastering part of the advanced self-assembly technology and self-innovation of the living world required scientific progress.

In 2018, Frances Arnold was awarded the Nobel Prize in Chemistry for her discovery of the so-called directed evolution of enzymes, including the production of unprecedented examples in the biological world. This means manipulating evolutionary principles that allow for self-innovation. Thus, it is possible to induce living organisms (bacteria) to build molecular machines (enzymes) of interest to man; For example, biostimulants that replace their more toxic synthetic equivalents. In 2020, it’s Emmanuelle Charpentier and Jennifer A. Doudna Nobel laureates, also in chemistry, for discovering a method of gene editing using the immune system of bacteria. The molecular scissors found by researchers make it possible to control the self-assembly processes of living cells and, who knows, open the way to new therapies against cancer and treatment of genetic diseases.

The next stage of the paradigm shift attracts not only chemists, but physicists as well. A limitation of the self-assembly technique has been, from the outset, the use of the genetic code and other biochemical mechanisms that evolved over the course of about three billion years. How did this genetic code and the first biochemical processes self-regulate, with only simpler molecules as the primary source? The question is intended to be broader than the search for the origin of life. The idea is to discover a variety of machines that are self-assembled, self-repairing, adaptable and, if possible, self-innovating, among the abundant core components. The goal is to learn the general physical principles that led to the transition from inanimate to living matter. In other words, the challenge is to find technologies inspired by the evolution of life.

As chemists investigate the manifestation of behavior similar to that of living organisms in aggregates of molecules, physicists want to test more diverse systems – photons, electrons, atoms, and macroscopic objects. In 2015, Dilip Kondibody A . led Experiment – Experiment Illustration in this line. He collected tens of milliliters of metal spheres immersed in viscous oil. The team of researchers showed that if an electric current from an external source passes through these domains, they organize themselves in the form of worms, and move like this. Metal worms also moved toward the energy source, reminding us of the intent of an organism in its search for a source of food. In this sense, the experience can be interpreted as a self-created type of metabolism. The system continues to recover independently in response to mechanical injuries. Although they show self-assembly inspired by living things, experiments like this still do not offer spontaneous innovations like those that give rise to new biological species.

On the theoretical front, there are promising hypotheses and models under discussion. Also in 2015, physicist Jeremy England proposed the concept of dispersed adaptation, a thermodynamic principle that describes how matter, when powered by certain energy sources, can become as structured and complex as the particles that make up a bacteria cell or a flying object. It is known that when the supply of external energy to any physical system, be it a machine or a living organism, is interrupted, the tendency for that system to reach the so-called thermodynamic equilibrium, the state of matter that best describes inert air. In a closed room the wind enters through an open window. If an organism is in thermal equilibrium, it is definitely not alive. But when the system is excited by external forces and receives energy capable of removing it from equilibrium, extraordinary phenomena can occur. In particular, atoms can participate in the internal movements that characterize a living system. The challenge remains in refining the current hypotheses and models, and confronting them with practice.

Technologies inspired by the transition from inanimate matter to living matter are a bold idea with the potential to advance basic science. Whether we can achieve it or not, that is the question.

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Daniel Valente is a physicist and professor at the Federal University of Mato Grosso (UFMT).

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