Fungi are stepping out of the forest and into our built environment, offering more than just the compressed mycelium composites used for packaging and insulation. The focus is shifting towards harnessing fungi as living materials, capable of complex functions like self-repair, environmental sensing, and even computation, opening a new chapter in sustainable construction and material science.
Moving Beyond Static Bricks: The Era of Living Fungal MaterialsWhile mycelium composites – where fungal threads (hyphae) bind organic waste like sawdust or agricultural by-products – represent a significant step towards sustainable materials, the true potential lies in keeping the fungal organism alive within the material. These Engineered Living Materials (ELMs) offer dynamic functionalities far beyond the static nature of traditional composites.
Recent breakthroughs showcase materials combining fungal mycelium (like Neurospora crassa) with living bacterial cells. These engineered biomaterials can be produced under low temperatures and demonstrate remarkable self-healing capabilities. When cracks form, exposure to air and moisture can potentially reactivate dormant fungal spores (or associated bacteria), prompting them to grow and fill the damage, often by precipitating minerals like calcium carbonate. Researchers have developed materials incorporating fungal mycelium and bacteria that can remain viable and functional, capable of self-repair, for over a month – a significant improvement over earlier biomaterials lasting only days or weeks.
Engineering Life: Guiding Growth and FunctionCreating these advanced materials involves sophisticated engineering techniques:
- Scaffolding and Formwork: Innovative methods like using knitted textile molds allow for the creation of complex, seamless structures ("mycocrete") with enhanced strength and predictable shapes compared to traditional molding. These techniques also improve oxygen availability crucial for the living organism. Researchers are exploring fungal scaffolds to guide internal geometries, creating structures resembling natural materials like cortical bone.
- Nutrient Control & 3D Printing: Precise deposition of nutrients using techniques like Direct Ink Writing (DIW) can manipulate fungal growth within a 3D-printed structure. By controlling nutrient distribution, researchers can promote or inhibit growth in specific areas, control material density, and create patterned surfaces, paving the way for tailored functional zones within a single material.
- Bio-welding: This technique involves growing discrete living fungal parts and then allowing them to fuse ("bio-weld") into a monolithic whole, enabling the construction of larger, integrated structures.
- Genetic Modification & Species Selection: While still developing, genetically modifying fungi or carefully selecting species (like Trichoderma reesei or certain Basidiomycota) with specific traits (e.g., resilience in alkaline concrete environments, enhanced mineral precipitation, radiation resistance) could unlock advanced functions, such as producing enzymes to break down pollutants or indicating structural stress. Some species form chlamydospores, hardy cells that may be key to long-term survival and self-healing capabilities in dry conditions.
The potential applications for living fungal materials are transformative:
- Self-Healing Structures: Buildings or components could autonomously repair minor cracks, significantly extending their lifespan and reducing maintenance costs and material consumption. This is particularly relevant for infrastructure where repairs are difficult or costly.
- Adaptive Environments: Materials could respond to environmental cues. For instance, engineered fungi might alter porosity for better air filtration in response to pollutants like wildfire smoke, or change thermal properties based on temperature.
- Integrated Sensing: Fungal networks could potentially act as biosensors, detecting structural stress, moisture changes, or the presence of specific chemicals within a building.
- Environmental Remediation: Materials could incorporate fungi or bacteria capable of breaking down pollutants or sequestering carbon dioxide, turning buildings into active participants in environmental cleanup.
- Space Construction: The ability to grow structures in situ from lightweight spores offers intriguing possibilities for building habitats on other planets, using local materials bound together by fungi.
Despite the excitement, significant hurdles remain. Maintaining the long-term viability of living organisms within the demanding environment of construction materials (alkalinity, dryness, temperature fluctuations) is a primary challenge. Scaling up production from lab prototypes to industrial levels consistently and cost-effectively is another major obstacle. The structural strength of current myco-materials, while improving, is not yet sufficient to replace load-bearing materials like concrete in all applications. Regulatory frameworks and public acceptance for using living organisms extensively in buildings also need development.
Future research focuses on enhancing cell survival, improving mechanical properties, optimizing large-scale manufacturing processes, and further exploring the integration of diverse biological functions. The collaboration between engineers, biologists, designers, and architects is crucial to realizing the potential of these "living buildings."
Engineering with living fungi represents a paradigm shift, moving from inert, resource-intensive materials towards dynamic, regenerative systems co-created with nature. It promises not just greener buildings, but structures that are adaptive, responsive, and potentially self-sustaining, harmonizing our built environment with the natural world.