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AbstractMycelium is crucial in decomposing biomass and cycling nutrients in nature. While various environmental factors can influence mycelium growth, the role of substrate mechanics is not yet clear. In this study, we investigate the effect of substrate stiffness on mycelium growth. We prepared agar substrates of different concentrations to grow the mycelium, but kept other environmental and chemical conditions consistent. We made a time-lapse recording of the growing history with minimum interruption. We repeated our tests for different species. Our results generally support that mycelium grows faster on a stiffer substrate,Ganoderma lucidumgives the highest growth rate andPleurotus eryngiiis most sensitive to substrate stiffness. We combined experimental characterization and computational simulation to investigate the mechanism and discovered that mycelium concentrates on the surface of a rigid substrate, but penetrates the soft one. Our Monte Carlo simulations illustrate that such a penetration allows mycelium to grow in the three-dimensional space, but effectively slows down the surface occupation speed. Our study provides insights into fungal growth and reveals that the mycelium growth rate can be tuned through substrate stiffness, thus reducing the time for producing mycelium-based composites. Impact statementWe used agar substrates and tuned its stiffness to culture mycelium and compared tune its stiffness to culture mycelium and compare its growth in a well-controlled condition. Our results revealed that mycelium grows faster on stiffer substrates, thus fully occupying the petri dish surface more quickly. We repeated our study several times by testing four species,P. eryngii,G. lucidum,Trametes versicolor,and Flammulina velutipes,and the stiffest substrate always gives the highest mean growing rate than others. TheG. lucidumshows the highest spreading rate that is obtained on the stiffest substrate as 39.1 ± 2.0 mm2/h. We found that the mycelium on a soft substrate will grow into the substrate instead of spreading on the stiffer surface. Our Monte Carlo simulations further show that once the fibers grow into a three-dimensional substrate, its growth is slower than growing on a two-dimensional surface, providing a microscopic mechanism of the substrate stiffness effect. This study’s analysis of how substrate stiffness impacts mycelium growth is new, bridging a critical knowledge gap in understanding the relationship between substrate mechanics and fungal ecology. The knowledge from this study has a potential in accelerating sustainable manufacturing of mycelium-based composite by adjusting substrate mechanics. Graphical Abstract
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Dynamic competition of inflation and delamination in the finite deformation of thin membranes
The mechanics of blister delamination and growth plays a major role in a diversity of areas including medicine (skin pathology and mechanics of cell membranes), materials (adhesive and fracture) or soft robotics (actuation and morphing). The behavior of a blister in this context is typically difficult to grasp as it arises from the interplay of two highly nonlinear and time-dependent processes: membrane attachment and decohesion from a substrate. In the present work, we device a simplified approach, based on experimental systems, to predict the deformation path of a blister under various conditions. For this, we consider the problem of a growing blister made of a rubber-like membrane adhered on a rigid substrate, and develop a theoretical and experimental framework to study its stability and growth. We start by constructing a theoretical model of viscoelastic blister growth which we later validate with an experimental setup. We show that blister growth is controlled by the competition between two instabilities: one inherent to the rubber, and a second one pertaining to the adhesion with the substrate. Using these concepts, we show that a “targeted” stable blister shape can be achieved by controlling two parameters: the thickness of the film and the inflation rate.
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- Award ID(s):
- 1761918
- PAR ID:
- 10192029
- Date Published:
- Journal Name:
- Soft Matter
- Volume:
- 15
- Issue:
- 33
- ISSN:
- 1744-683X
- Page Range / eLocation ID:
- 6630 to 6641
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C9SM00988D
