Spatial and temporal characterization of living mycelium through dispersion analysis

Abstract Mycelium, a natural and sustainable material, possesses unique electrical, mechanical, and biological properties that make it a promising candidate for biosensor applications. These properties include its ability to conduct electrical signals, respond to external stimuli such as humidity and mechanical stress, and grow integrally within structures to form a natural network. Such characteristics suggest its potential for integration into self-sensing systems to monitor vibrations, deformations, and environmental conditions in buildings and infrastructure. To understand the output voltage generated by this biomaterial in response to an applied electrical input, it is essential to characterize their spatial and temporal properties. This study introduces an electrical impedance network model to describe signal transmission through mycelium. In combination with the inhomogeneous wave correlation method-commonly used in elastic wave propagation-we demonstrate, for the first time, the dispersion behavior of living mycelium both theoretically and experimentally. We reveal the frequency-dependent and spatial attenuation of electrical signals in living, dehydrated, and rehydrated mycelium, emphasizing the critical role of humidity in enabling effective signal sensing. At low-to-mid frequencies the response appears macroscopically uniform across directions, whereas at higher frequencies it becomes direction-dependent and less uniform, likely due to heterogeneity and dielectric polarization dispersion. Furthermore, dispersion analysis is used to assess the homogeneity of mycelium, underscoring its feasibility as a living, green sensing material. This research lays the groundwork for innovative applications of mycelium in sustainable structural health monitoring.