Engineered living materials

In plain language

Engineered living materials (ELMs) are materials made with living cells, or with the structures that cells produce. In some ELMs the cells stay alive in the finished object. In others, cells work only as tiny factories during manufacture and are then removed or made inactive. The label describes a research field rather than one ability, and it does not on its own tell you whether anything in the final product is alive.

A 2024 study in Nature Communications made a thin film from bacteria. The bacteria produced protein fibres called curli, which formed a mesh. The researchers processed the cells and fibres into a sheet with some of the characteristics of paper, and its stiffness and stretch could be changed by altering the fibres and how the film was made. In laboratory tests the film broke down in fish-manure compost within 15 to 75 days. The team also joined cut pieces with about 10 microlitres of water. These are early laboratory results. They do not show that the material can repair itself in use, or that it can replace plastic packaging.

Technical explanation

ELM research combines synthetic biology with materials science. Living cells, the materials they make (such as fibres, polysaccharides or minerals), and biological processes are used to assemble a bulk material with designed properties. Early reviews focused on engineered bacterial systems and living composites that include inorganic components, and framed the ambition as materials with the autonomous, adaptive and self-healing features of living organisms (Nguyen and colleagues, 2018). A later review describes ELMs as materials created bottom-up, and distinguishes them from hybrid living materials, which are made by means such as encapsulation or bioprinting (Hernández-Arriaga and colleagues, 2021). A 2020 taxonomy paper by Srubar proposed categories for the growing ELM literature and described the field as a standalone discipline (Srubar, 2020).

The best-documented example in the sources reviewed is MECHS, a film made from cultured bacterial biomass containing engineered curli protein nanofibres (Manjula-Basavanna and colleagues, 2024). The authors report that about 40% of the total cellular and curli biomass is incorporated into the film, with a yield of 0.5 to 1 grams per litre of culture. Across their formulations they report elongation at break from 1% to 160% and Young's modulus from 6 to 450 MPa. These are ranges across different formulations and test conditions, not the properties of a single film. Genetically encoded covalent crosslinking of the curli fibres roughly doubled the modulus in the paper's comparison. The compost test used 5 by 5 cm samples in fish-manure compost at 20 degrees Celsius and 80% relative humidity. Fresh compost degraded the samples completely in 15 days, and compost that had been dried for 50 days did so in 75 days.

Several caveats matter for technical readers. The water-joining process, called aqua healing, used about 10 microlitres of water at a cut, followed by drying under laboratory conditions. The authors' own water-dissolution test showed that the films did not fully dissolve, even though the paper's abstract describes the material as flushable. ISO 14855-1:2012 is a standard laboratory method for aerobic biodegradability under controlled composting conditions, based on measuring evolved carbon dioxide (ISO, 2012). The sources reviewed do not show that the MECHS compost test followed that standard, so its results cannot be read against it without checking the paper's methods.

What the evidence says

Each statement is typed by the strength of its evidence and linked to the source that supports it.

Limitations and open problems

• The MECHS results come from laboratory-scale production: a 5 by 50 cm film came from 6 litres of culture. The authors do not describe a complete manufacturing process, and scale-up would need consistent batches, contamination control, energy and water accounting and cost comparisons (Manjula-Basavanna and colleagues, 2024).
• The authors state that ultimate tensile strength, tear strength and resistance to water need further improvement (Manjula-Basavanna and colleagues, 2024). A film with a useful stiffness may still tear, soften when wet or fail at folds and seams.
• The compost test covered one kind of fish-manure compost at 20 degrees Celsius and 80% relative humidity, using small samples. It does not show how the material would break down in a home garden, landfill, marine setting or wastewater system, and the paper's flushability claim is not supported by a tested pass.
• Finished films contain bacterial biomass and engineered fibres. Living cells or self-repair are not shown for the finished product, and the water-assisted joining was a laboratory demonstration rather than repair by an unattended product.
• The sources reviewed do not include a full life-cycle assessment. Feedstock, fermentation, purification, drying, transport, product lifetime and disposal would all need to be counted, and the authors themselves note the need for feedstock derived more closely from carbon dioxide fixation.

Possible future uses

Product concepts: Bacterial-fibre test block

Timeline

1. 1 Dec 2012Second edition of ISO 14855-1 published, setting out a laboratory method for the ultimate aerobic biodegradability of plastics under controlled composting conditions. Sources: [5]
2. 12 Feb 2018Review in Advanced Materials sets out prospects and challenges for engineered living materials built with engineered bacterial systems. Sources: [2]
3. 21 Nov 2020Taxonomy of engineered living material research published in Trends in Biotechnology. Sources: [3]
4. 12 Nov 2024MECHS film, made from engineered curli protein fibres in cultured bacterial biomass, published in Nature Communications. Sources: [1]

Futures this could help bring about

How far away?

Materials that grow and repair themselves

Engineering prototypes · 4 of 8 steps done

Glossary

Engineered living material (ELM)

A material designed with living cells, cell-produced structures or biological processes. The term does not by itself say whether cells remain alive in the final object.

Curli

Protein fibres produced by certain bacteria that assemble into a mesh-like structure.

Young's modulus

A measure of stiffness. A higher value means more stress is needed for a given elastic deformation.

Elongation at break

How far a sample stretches before it breaks, expressed relative to its starting length.

Sources

1. peer reviewed paper
   Mechanically Tunable, Compostable, Healable and Scalable Engineered Living Materials
   Avinash Manjula-Basavanna, Anna M. Duraj-Thatte, Neel S. Joshi. Nature Communications, 12 Nov 2024. DOI: 10.1038/s41467-024-53052-4. Accessed 21 Oct 2026.
2. review article
   Engineered Living Materials: Prospects and Challenges for Using Biological Systems to Direct the Assembly of Smart Materials
   Peter Q. Nguyen, Noémie-Manuelle Dorval Courchesne, Anna Duraj-Thatte et al.. Advanced Materials, 12 Feb 2018. DOI: 10.1002/adma.201704847. Accessed 21 Oct 2026.
3. review article
   Engineered Living Materials: Taxonomies and Emerging Trends
   Wil V. Srubar III. Trends in Biotechnology, 21 Nov 2020. DOI: 10.1016/j.tibtech.2020.10.009. Accessed 21 Oct 2026.
4. review article
   When microbial biotechnology meets material engineering
   Ana M. Hernández-Arriaga, Cristina Campano, Virginia Rivero-Buceta et al.. Microbial Biotechnology, 24 Nov 2021. DOI: 10.1111/1751-7915.13975. Accessed 21 Oct 2026.
5. standard
   Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions: Method by analysis of evolved carbon dioxide, Part 1: General method (ISO 14855-1:2012)
   International Organization for Standardization, 1 Dec 2012. Accessed 21 Oct 2026.

Revision history

3 changes since this profile was created.