The future of construction is alive, green and mineralizing

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Imagine that the concrete in your walls, or some siding materials, or even the tiles on your roof, were alive. Imagine that, through photosynthesis, they capture carbon dioxide from the atmosphere, and that they also precipitate it through other biochemical mechanisms to strengthen their structure, forming minerals like those found in limestone mountains, arranged in a sort of well-formed skeleton with well-defined structural properties.

Now stop imagining, because this idea, thanks to the collaboration between biologists, materials engineers and architects, has reached the prototype stage: the details can be read in Nature Communications , but even more, some of the creations are on display until November in our country.

A research group at ETH Zurich has developed a surprising material: a printable "living" gel containing ancient cyanobacteria, capable not only of autonomous growth but also of dually extracting CO₂ from the atmosphere . These microorganisms exploit sunlight to produce biomass and, at the same time, modify their external chemical environment, favoring the precipitation of mineral carbonates that trap additional quantities of carbon in a stable form. The gel, based on hydrogels specifically engineered to ensure permeability to light, carbon dioxide, water, and nutrients, offers an optimal habitat in which the cells are evenly distributed and remain viable for over a year, while the mineral deposits progressively strengthen the structure, making it increasingly solid.

The unique feature of this "living material" is its ability to store CO₂ not only through the accumulation of biomass, but above all in the form of minerals: thanks to the metabolism of cyanobacteria, in fact, over more than 400 days, each gram of material is able to capture approximately 26 milligrams of CO₂, a performance superior to many current biological solutions and comparable to the chemical mineralization of recycled concrete . This dual form of sequestration makes it particularly interesting for low-energy building applications, where it could serve as a cladding or structural component capable of capturing carbon for the entire useful life of the structure.

To optimize the viability and efficiency of the microorganisms, researchers used 3D printing techniques to shape the artifacts into geometries designed to maximize the surface area exposed to light and promote the capillary distribution of nutrients. Thanks to these measures, the structures maintain prolonged metabolic stability and gradually transform from a soft gel to a more rigid material, generating a novel synergy between biology and polymer engineering . The research, published in Nature Communications, thus paves the way for a new generation of materials that grow and self-repair, integrating novel environmental functions.

The potential of this technology has already attracted interest from the architecture world: at the Venice Biennale, the Picoplanktonics installation was presented in the Canadian Pavilion, where tree-trunk-like modules up to three meters tall, made of living gel, act as "bricks" capable of capturing up to 18 kilograms of CO₂ per year, a yield comparable to that of a 20-year-old pine tree in a temperate zone. The project, coordinated by architect and PhD student Andrea Shin Ling, required complex scaling to adapt the manufacturing process from laboratory micrometers to architectural dimensions, ensuring controlled conditions of light, humidity, and temperature, and daily monitoring of the microbial colonies.

At the same time, the Milan Triennale hosts the exhibition "We the Bacteria: Notes Toward Biotic Architecture," featuring Dafne's Skin, an interactive coating designed by Maeid Studio and researcher Dalia Dranseike, where microorganisms colonize wooden tiles, forming a dark green patina that evolves over time. This "bacterial skin" not only decorates the surface but transforms it, transforming a sign of decay into a functional aesthetic element, capable of binding CO₂ and suggesting new languages ​​for building facades. Both works, on display until November in Venice and Milan respectively, demonstrate how the ETH's Alive ( Advanced Engineering with Living Materials ) initiative is producing its first tangible results.

More generally, these works point the way to the realization of a wonderful idea: building with living materials, workable at will, capable of making a substantial contribution to combating climate change and at the same time providing useful materials for construction and other sectors, exploiting the intersection of biology, materials engineering, and architecture.

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