In the artificial cell forest, these tiny factories replicate organisms

On a computer screen coupled to an ultrafast camera, itself attached to a microscope lens, a crowd of fluorescent and granular spheres more or less coexist. “We can compare the photosynthetic activity of three types of droplets, depending on the intensity of fluorescence.”Explains Jean-Christophe Barrett. It describes the microfluidic system that makes it possible to create these droplets through which organic molecules are produced, as in plants, under the influence of light.

We are at the Paul Pascal Research Center, on the Pessac campus, on the outskirts of Bordeaux. One of the ingredients being injected into the microfluidic circuits is none other than finely blended spinach, which provides the thylakoids, components of chloroplasts and the headquarters of photosynthesis in plant cells. But the rest of the recipe is synthetic and occurs at the end of microscopic channels that converge to produce subtly measured mixtures, resulting in the formation of membrane-less droplets, called coacervates, replicas of specific components of living cells.

Jean-Christophe Barry, a professor at Purdue University, heads a team that specializes in the study of artificial or synthetic cells, a discipline as plentiful and unstructured as life, and aims to emulate. To explain this approach, he willingly quotes Alexander Oparin (1894-1980). Almost a century ago, in 1924, this Russian biochemist formulated a hypothesis about the origin of life: it would have appeared as droplets, “protocells” concentrating primordial chemical elements capable of interacting with each other. Others generate complex interactions. Preempt living cells.

Remember that this is the basic constituent unit of all organisms living on Earth – the human body has about a hundred thousand billion, to which is added a microbiota, ten times its population of microbes! A somewhat flexible envelope surrounds the cell, isolating it from its environment while allowing it to interact with it. It summarizes the genetic heritage translated into proteins, ensuring its functioning and reproduction, with a basic margin of error for evolution through generations. This bag, which is an average of a few tens of micrometers in diameter, is also filled with a host of organelles that ensure their metabolic functions, structure, growth, motility, etc.

You have 83.49% of this article left to read. The following is for subscribers only.