TU Delft 3D Prints Living Mycelium That Assembles Its Own Functional Materials
- Gauri Khanna
- Jun 25
- 3 min read
Researchers at Delft University of Technology have 3D printed living structures from Ganoderma lucidum mycelium that continue to grow and self-assemble functional particles after printing.
The fungus captures nano- and micro-particles from its liquid growth medium, with carbon black particles boosting electrical signal amplitude by roughly nine times compared to non-functionalized samples.
The approach could open a new class of living materials capable of sensing, environmental monitoring, and adaptive behaviour, though the work remains at an experimental stage.
Fungal Growth as a Manufacturing Step
Most approaches to mycelium-based materials treat the organism as a binder or structural filler, something to be dried, compressed, and finished. A study published in Advanced Functional Materials by researchers at TU Delft's Shaping Matter Lab, within the Faculty of Aerospace Engineering, takes a different view: the fungus itself is the fabrication process.
The team, led by Sarah Schyck, Mark Ablonczy, Sourav Patranabish, and Kunal Masania, used Ganoderma lucidum, a filamentous fungus widely studied for its growth properties, as the biological engine of their system. Rather than simply casting mycelium into a mould and letting it cure, they printed living fungal structures and then allowed continued growth to pull functional particles directly into the material.
In liquid culture, Ganoderma lucidum naturally forms pellets, compact masses of intertwined hyphae (the thread-like filaments that make up fungal networks). The size and density of these pellets depends on agitation speed, nutrient availability, and incubation time. The researchers found that particle incorporation was strongly governed by particle size: nanoparticles of around 30 nanometres adsorbed directly onto hyphal cell walls, creating a surface-coating effect, while larger particles of around 45 micrometres became physically entangled within the growing network. By adding particles sequentially, the team could build pellets with distinct functional layers, an early demonstration of spatial material control during biological growth.
Printing, Growing, and Selectively Functionalising
To introduce geometric control, the team formulated a bioink containing sodium alginate, κ-carrageenan, agar, and a cellulose-based thickener, loaded with active hyphal fragments. Structures were printed using direct ink writing, a method that extrudes material through a nozzle to build up a shape layer by layer, and then cross-linked with calcium chloride to stabilise the scaffold during submerged cultivation.
The printed scaffold preserved the initial geometry while the mycelium continued growing outward into the surrounding medium. Over time, sharp printed edges softened as the fungal network expanded beyond the original structure. The researchers tracked this shape evolution quantitatively using superellipse fitting, a mathematical method for describing how rounded or angular a shape is.
Spatial control was further refined using a gelatin masking technique. By temporarily embedding portions of a living print in gelatin and exposing only selected regions to particle-containing media, the team achieved localised particle deposition, meaning different parts of the same structure could be functionalised independently.
Carbon Particles and Bioelectric Signalling
The most striking results came from the electrical characterisation experiments. Printed mycelium struts, grown with and without conductive carbon black particles, were placed on patterned indium tin oxide electrodes and their bioelectric signals measured. Living, carbon-functionalised samples produced a signal-to-noise ratio 2.7 times higher than non-functionalised counterparts, and peak signal amplitude roughly nine times greater. Higher carbon loading also reduced electrical impedance, suggesting the particles were genuinely improving connectivity through the living hyphal network rather than simply sitting inertly within it.
The researchers also demonstrated a modular replacement concept: underperforming mycelium blocks could be substituted with fresh units, partially restoring bioelectric signal across a composite structure, a property with obvious relevance for self-repairing or adaptive systems. This connects to broader work on engineered living materials that can sense and respond to their environment.
Limitations and the Road Ahead
The study is explicitly experimental. The multi-material pellets produced in the free-floating liquid culture experiments were noted by the authors to be fragile and susceptible to deformation during handling; additional processing would be needed before they could serve as functional components. The bioelectric measurements were conducted on printed struts supported by the hydrogel scaffold, a separate configuration from the pellet-based experiments, so the two parts of the study should not be read as a single unified system.
What the work does establish is a proof of concept: that 3D printing and post-print biological growth can be combined to create materials that are shaped first and functionalised afterward. As mycelium-based fabrication continues to mature, the ability to direct where and how functional particles are incorporated, using the fungus's own growth as the assembly mechanism, represents a meaningful step toward genuinely programmable living materials.
