Bottom-up fabrication of high-strength mycelium-based materials: Tween as a bioregulator of mycelium growth

Mycelium-based materials represent a promising sustainable alternative to petroleum-based plastics. However, their broad-scale application remains hindered by intrinsic mechanical frailty and the ubiquitous strength-toughness trade-off. In this work, we present a bottom-up fabrication strategy that overcomes these limitations by engineering desirable material properties during the biological growth phase. Specifically, by introducing Tween-20 as a bio-regulator during the liquid culture of Ganoderma lucidum, thereby enabling programmable, synergistic multiscale structural reinforcement through endogenous fungal metabolism. At the macroscale, this approach orchestrates the spontaneous self-assembly of a densely entangled three-dimensional hyphal network, significantly enhancing load transfer. At the microscale, Tween-20 modulates cell wall composition and fatty acid biosynthesis, priming the matrix for robust covalent ester cross-linking with a glycerol-based plasticizer. Critically, Tween-20 functions as a metabolic elicitor that directs in situ structural programming and chemical consolidation within a single fabrication cycle. The resulting biomaterial achieves outstanding mechanical performance, with a tensile strength of 24.21 MPa, a Young's modulus of 116.45 MPa, and a toughness of 2909.47 kJ m^-3, substantially surpassing the corresponding values obtained for previously reported pure mycelium-based materials. Moreover, the material demonstrates integrated multifunctionality, including hydrophobicity, thermal stability, antibacterial activity, and biodegradability. This study establishes a scalable, environmentally benign platform for high-performance biocomposites manufacturing and provides a foundational design paradigm for next-generation sustainable consumer goods and packaging solutions.