Quantifying the Mechanics of Engineered Mycelium Films

Many of the current synthetic polymers lack features typically associated with biological systems: programmable material properties, self-regenerating capabilities, and compatibility with sustainable and scalable manufacturing practices. These qualities can be cultivated by leveraging living microbes, which is an emerging area of research known as engineered living materials (ELMs). Of interest in this field has been mycelium-based materials, which have applications in alternative packaging, construction, and medicine. Previous research on the mechanical properties of mycelium films has focused on comparing the mechanics of different fungal species, while there has been less emphasis on understanding the impacts of extracellular polymeric substance (EPS) composition, branching, and hydration. Here, we bridge this gap by investigating the uniaxial stress-strain response of Aspergillus niger fungal films engineered to act as a living template for biomineralization. We observe that the non-mineralized films of A. niger exhibit a larger elastic modulus, yield stress, and lower toughness than the biomineralized films. Our results provide fundamental insights into how biomineralization and hyphae structure impact the mechanical properties of mycelium films.