Topology Optimization of 3D Printed Hierarchical Porous Mycelium Hydrogels

The regenerative and adaptive properties of biological living materials make them an exciting candidate for sustainable and resilient material design. Mycelial hydrogels—hydrogels loaded with <i>Ganoderma lucidum</i> for 3D-printing applications—have shown to be mechanically robust, with their printability allowing for complex geometric control of the material lattice. As printable hierarchical porous materials, the tunable porosity of these lattices opens a new dimension of customizability for a wide array of structural applications, leveraging differing geometric and topological features across multiple scales. However, with such design freedom in terms of material shape, microstructure, and functionality, topology optimization is the key to effectively utilizing the full potential of this material. In this work we describe a framework for optimizing the topology of 3D printed mycelium hydrogel structures. This system considers engineered and natural parameters, manipulating print design and spacing as well as mycelial growth patterns to optimize the mechanical strength of a given design configuration for strength-to-weight optimization. By identifying morphologic descriptors that link microstructural geometry and topology to macroscale functionality, we unlock a high degree of multiscale control for this class of porous materials, allowing for a complex and flexible design scheme for these novel printed systems.