Page 176 - IJB-10-5

International

Journal of Bioprinting

RESEARCH ARTICLE
Manipulating fungal growth in engineered living

materials through precise deposition of nutrients

Jia Heng Teoh , Eugene Soh , and Hortense Le Ferrand 1,2,3,4, id
*
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1 School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
2 School of Materials Science and Engineering, Nanyang Technological University, Singapore
3 Singapore Center for 3D Printing, Nanyang Technological University, Singapore
4 Future Cities Laboratory, Singapore ETH Centre, Singapore

Abstract
One main challenge of emerging fungal-based engineered living materials (ELMs) lies
in achieving localized multi-material properties in these structures. Although three-
dimensional (3D) printing can efficiently vary local composition and properties, it
has not yet been demonstrated in fungal-based ELMs. This work thus explores the
concept of using nutrients to manipulate fungal foraging behavior in 3D structures
fabricated using direct ink writing (DIW) for the next generation of fungal-based
ELMs. Using two fungal strains (Pleurotus ostreatus and Ganoderma lucidum), this
study showed that the ink formulation used is suitable for both DIW and mycelium
growth. Varying the nutrient content allows for either the inhibition or promotion of
exploration and bridging of mycelium in different sections, the control of mycelium
density in three dimensions and the fabrication of patterned surfaces. There is
*Corresponding author: potential in fabricating patterned fungal-based ELMs and lab-on-a-chip systems
Hortense Le Ferrand to investigate the effects of other substances and microorganisms on the foraging
(hortense@ntu.edu.sg)
behavior of mycelium.
Citation: Teoh JH, Soh E,
Le Ferrand H. Manipulating
fungal growth in engineered Keywords: 3D printing; Direct ink writing; Engineered living material; Mycelium;
living materials through precise Hydrogel; Foraging behavior
deposition of nutrients.
Int J Bioprint. 2024;10(5):3939.
doi: 10.36922/ijb.3939
Received: June 14, 2024
Revised: July 18, 2024 1. Introduction
Accepted: July 27, 2024
Published Online: July 30, 2024 Engineered living materials (ELMs) are an emerging type of biomaterials that utilizes
living cells to give functionalities to an otherwise inanimate material. Among other
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Copyright: © 2024 Author(s).
This is an Open Access article cells, fungal-based ELMs—which incorporate filamentous fungus that form a three-
distributed under the terms of the dimensional (3D) net of fungal cells called mycelium—have demonstrated interesting
Creative Commons Attribution properties leading to potential applications such as self-healing textiles, living
4–6
License, permitting distribution,
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and reproduction in any medium, structures, or robotics. In designing fungal-based ELMs, it is important to ensure that
provided the original work is the fungus is growing effectively throughout the structure with the desired mycelium
properly cited. density. Mycelium is known to grow a uniform fungal skin on the exterior of the
Publisher’s Note: AccScience structure at the material–air interface, whereas the center of the structure is usually
Publishing remains neutral with devoid of mycelium due to positive aerotropism. Being able to control the growth
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regard to jurisdictional claims in
published maps and institutional of mycelium in materials is instrumental for tailoring the mechanical properties of
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affiliations. the structure, in particular its stiffness. Furthermore, for ELMs to function as living
Volume 10 Issue 5 (2024) 168 doi: 10.36922/ijb.3939