In a quiet lab at ETH Zurich, researchers have achieved a milestone that sounds like science fiction: a living building material that captures carbon dioxide from the air — and keeps it there.
This breakthrough, published in Nature Communications, is the result of a collaboration between chemists, engineers, and architects who have spent years working to integrate bacteria, algae and fungi into conventional materials, to create “living materials” with useful properties. Their latest innovation is a 3D printable hydrogel infused with cyanobacteria, ancient microorganisms that perform photosynthesis, absorbing CO₂ and converting it into stable forms of carbon.
What sets this material apart isnt just its ability to grow — its how efficiently it sequesters carbon. According to ETH Professor Mark Tibbitt, who leads the Macromolecular Engineering group, the bacterias metabolism not only supports their own biomass growth but also alters their surrounding chemistry, causing minerals such as lime to precipitate within the gel. These mineral deposits both reinforce the structure and lock away carbon in solid form.
“As a building material, it could help to store CO2 directly in buildings in the future,” said Tibbitt, who helped launch the research into living materials at ETH Zurich.
“Cyanobacteria are among the oldest life forms in the world,” said Yifan Cui, co-lead author of the study. “They are highly efficient at photosynthesis and can utilize even the weakest light to produce biomass from CO₂ and water.”
In laboratory testing, the material removed around 26 milligrams of CO₂ per gram — significantly outperforming many existing biological and recycled concrete materials.
The living matrix, a carefully designed hydrogel, ensures that light, water, nutrients, and gases can move freely. Using 3D printing, researchers optimized the shapes of the structures to enhance surface area and nutrient flow. That geometry, combined with capillary forces, allowed the bacteria to thrive for over a year.
This concept of architecture as carbon sink has already moved beyond the lab. At the Venice Architecture Biennale, visitors to the Canada Pavilion encounter Picoplanktonics, an installation of tree-like columns made with the new material. The three-meter-tall forms are not just symbolic; each one can absorb as much carbon annually as a 20-year-old pine tree.
Scaling up production for the Biennale was a major challenge, said Andrea Shin Ling, the ETH doctoral student behind the installation. But the process also allowed her to test biofabrication at a real-world scale — a crucial step toward integrating these materials into everyday buildings.
“The installation is an experiment — we have adapted the Canada Pavilion so that it provides enough light, humidity and warmth for the cyanobacteria to thrive and then we watch how they behave,” Ling said. The team is monitoring the installation daily through Nov. 23.
A second exhibition in Milan, Dafnes Skin, explores how such living materials might evolve into building façades. Created by architect Dalia Dranseike and MAEID Studio, the installation uses microorganisms to form a green patina over wooden shingles, turning natural weathering into a visible, climate-active feature.
The ETH team sees these projects as the beginning of a new design paradigm, where buildings dont just passively stand — they live, change, and clean the air around them.
“In the future, we want to investigate how the material can be used as a coating for building façades to bind CO2 throughout the entire life cycle of a building,” Tibbitt said.
