Researchers at Delft University of Technology (TU Delft) have developed a 3D printing approach for shaping living mycelium materials that can self-assemble functional particles during growth. Published in Advanced Functional Materials, the study demonstrates how fungal networks can be printed, grown, and selectively functionalized to create biohybrid living materials with tunable electrical properties.
The work was led by researchers from the Shaping Matter Lab at TU Delft’s Faculty of Aerospace Engineering. The researchers used Ganoderma lucidum, a filamentous fungus, embedding active hyphal fragments into a cross-linkable hydrogel ink for direct ink writing.
Rather than treating fungal growth as a secondary biological effect, the study uses it as part of the fabrication process. As the mycelium grows out from the printed scaffold, it captures particles from the liquid medium, adding functionality to the material after printing.
Fungal growth as a manufacturing mechanism
The researchers examined how mycelium pellets form in liquid culture. In agitated growth media, the fungus develops into pellets whose size and morphology depend on shaking conditions, nutrient availability, and incubation time. Higher agitation produced smaller fragmented pellets, while lower agitation supported larger structures.
Particle incorporation depended strongly on particle size. Nanoparticles measuring around 30 nm adsorbed onto the fungal hyphae, creating an “armoring” effect along the cell walls. Larger particles, measuring around 45 µm, became physically entangled within the growing mycelial network. The researchers also showed that particles could be added sequentially to create multi-material pellets with distinct functional rings.
This suggests that fungal growth can be used to assemble functional materials during cultivation, rather than simply binding pre-mixed ingredients into a printed form.
3D printing living fungal structures
To introduce shape control, the team developed a mycelium-laden bioink containing sodium alginate, κ-carrageenan, agar, and a cellulose-based thickener. The ink was printed using direct ink writing and then cross-linked with calcium chloride to maintain its structure during submerged cultivation.
The printed hydrogel scaffold helped preserve the starting shape while still allowing the mycelium to grow into the surrounding medium. Over time, the mycelium grew outward from the printed structure, rounding corners and edges. The researchers tracked this shape evolution using superellipse fitting, showing how the geometry changed from the as-printed form to a smoother, overgrown structure.
The study also introduced a selective functionalization method using gelatin as a temporary mask. By embedding parts of the living print in gelatin and exposing only selected areas to particle-containing media, the researchers created localized particle deposition. This allowed different regions of the same living structure to be functionalized with greater spatial control.
Carbon particles improve bioelectric signaling
The team then investigated whether conductive carbon particles could enhance bioelectric signals in the living fungal material. Printed mycelium struts were grown with and without carbon black particles and placed on patterned indium tin oxide electrodes for measurement.
Living, carbon-functionalized samples showed stronger electrical activity than non-functionalized samples. The paper reports conductive carbon particle incorporation increased the signal-to-noise ratio by 2.7 times and peak amplitude by around 9 times. The researchers also found that higher carbon loading reduced impedance, suggesting improved electrical connectivity through the living network.
Toward adaptive biohybrid materials
The researchers also explored modular fungal building blocks that could be assembled and replaced. In one demonstration, underperforming mycelium blocks were substituted with fresh units, restoring the bioelectric signal across the structure.
The work remains at an experimental stage. In the free-floating pellet experiments, the researchers note that the multi-material pellets were relatively fragile and susceptible to deformation during handling, indicating that further processing would be needed to turn those pellet-based structures into functional materials. The 3D printed struts used for bioelectric measurements were supported by the printed hydrogel scaffold, making this a separate part of the study.
By combining 3D printing with continued fungal growth, the study shows how mycelium-based materials can be shaped first and functionalized later. The approach could inform future living materials designed for sensing, environmental monitoring, remediation, or adaptive systems.
Mycelium 3D printing moves beyond structural composites
Recent research has explored how fungal growth can be combined with additive manufacturing to produce more sustainable materials. In 2023, researchers developed a fungi-based 3D printing material that used mycelium as an oriented fiber reinforcement for printed unfired clay, pointing to the structural role fungal networks can play in printed composites. More recent work has also examined bio-welding, where living mycelium helps fuse separate printed parts after fabrication.
What sets the TU Delft study apart is using the fungus’s own growth to pull in and organize functional particles. The printed shape serves as a scaffold, but the real material assembly occurs afterward in the liquid medium, where carbon particles improved electrical signaling by an order of magnitude.
Titled, “Shaping of Biohybrid Functional Living Materials,” the study was conducted by Sarah Schyck, Mark Ablonczy, Sourav Patranabish, and Kunal Masania.
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Featured image shows selectively functionalized 3D printed mycelium structures, including a mushroom-shaped print with particle deposition on the cap. Image via Schyck et al.
