Gradients of Aliveness and Engineering: A Taxonomy of Fungal Engineered Living Materials.

Filamentous fungi offer unique potential for engineered living materials (ELMs), enabling self-assembling, adaptive, and sustainable biofabrication. However, the field lacks a systematic framework to classify fungal ELMs, as they vary in biological state (dead, dormant, or living), scaffold composition, and degree of engineering intervention. Here, a classification system is introduced to categorize fungal ELMs, enabling researchers to map existing studies and guide future development. The ability to form resilient 3D networks make filamentous fungi ideal for applications ranging from self-healing composites to materials for bioremediation and real-time sensing, as demonstrated in proof-of-concept applications. A roadmap for next-generation fungal ELMs is outlined, including spatial-temporal control of fungal states, multispecies integration for enhanced complexity, and computational modeling for predictive design. Key challenges, such as contamination control, cell viability, and bio-digital integration, are discussed alongside strategies for genetic engineering. Finally, ethical and environmental considerations are emphasized as crucial factors for the responsible scaling of fungal ELMs.