At ETH Zurich, a public research university, an interdisciplinary team led by Professor Mark Tibbitt has developed a 3D printable hydrogel infused with cyanobacteria—photosynthetic microorganisms that absorb carbon dioxide from the atmosphere and convert it into both organic biomass and stable, carbonate-based minerals. This innovation aims to reduce the carbon footprint of buildings and infrastructure by passively sequestering CO₂ over time.
“We see our living material as a low-energy and environmentally friendly approach that can bind CO₂ from the atmosphere and complement existing chemical processes for carbon sequestration,” said Mark Tibbitt, Professor of Macromolecular Engineering at ETH Zurich.
How It Works and Why It Matters
As reported in Nature Communications, the material grows and hardens over time while continuously capturing CO₂, relying solely on light and a nutrient-rich artificial seawater solution. What distinguishes it is its dual carbon sequestration strategy, enabling it to absorb more CO₂ than it stores through organic growth alone.
“This is because the material can store carbon not only in biomass, but also in the form of minerals – a special property of these cyanobacteria,” reveals Tibbitt.
The living cells are embedded within a hydrogel—an aqueous network made of cross-linked polymers with a high water content. The team selected the polymer structure to facilitate the transport of light, carbon dioxide, water, and nutrients throughout the material, while ensuring the cyanobacteria remain evenly distributed and contained within it.
To maximize the longevity and efficiency of the cyanobacteria, the researchers optimized the geometry of the structures using 3D printing techniques. This design enhances surface area, improves light penetration, and promotes nutrient circulation within the material.
Laboratory experiments demonstrated that the material steadily captures CO₂ for up to 400 days, primarily storing it as minerals—approximately 26 milligrams of CO₂ per gram of the material. This performance exceeds many biological methods and rivals the chemical mineralization found in recycled concrete, which stores around 7 milligrams of CO₂ per gram.
Future Applications and Outlook
The researchers emphasize that their living material represents an energy-efficient and environmentally sustainable approach to capturing atmospheric CO₂, with potential to complement existing chemical sequestration methods.
“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,” says Tibbitt.
Advancing Sustainable Construction Through 3D Printing
3D printing is increasingly being applied to reduce the environmental impact of traditional construction methods. In line with this trend, UK energy company National Grid has launched a UK-first trial to manufacture, install, and test 3D printed concrete foundations for substations, in collaboration with Finnish concrete 3D printing specialist Hyperion Robotics and the University of Sheffield in the UK. The project aims to assess whether this construction method can reduce carbon emissions, minimize material waste, and lower overall network infrastructure costs.
Similarly, the University of Virginia (UVA) has made strides in enhancing the sustainability of 3D printed concrete. Researchers there developed a cementitious composite by incorporating graphene nanoplatelets (GNPs) into limestone-calcined clay (LC2). Remarkably, adding just 0.05% GNPs by weight enhanced the compressive strength of the concrete by 23% while reducing greenhouse gas emissions by nearly 31% compared to traditional cement mixtures. This graphene-enhanced concrete boosts structural performance and supports environmental objectives by lowering the carbon footprint of construction materials.
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Featured image shows Continuous culture over 400 days. Photo via ETH Zurich.
