Researchers in Switzerland have developed a biohybrid material by infusing wood with a naturally bioluminescent fungus, resulting in a stable composite that glows in the dark. The project, led by a team at Empa, the Swiss Federal Laboratories for Materials Science and Technology, harnesses a natural phenomenon sometimes called “foxfire” to create a luminous material with the potential for a variety of novel applications.
The innovation is part of a broader scientific effort to increase the sustainable use of natural resources. By imparting new functionalities to hardwood, scientists aim to create a “cascade use” model, extending the material’s life cycle for applications in design or technology before it is ultimately disposed of or used as a fuel source. This approach seeks to keep the carbon dioxide stored within the wood from being released into the atmosphere, which occurs when it is burned.
A Fungus-Based Impregnation Method
The creation of the glowing wood involves a meticulous laboratory process centered on the interaction between wood and a specific fungus. The team, led by fungal researcher Francis Schwarze, selected the ringless honey fungus, Desarmillaria tabescens, for its ability to produce a strong glow. This organism is a pathogen that causes white rot in trees, a process that involves breaking down a key structural polymer in wood.
For the substrate, the researchers chose balsa wood. In controlled lab conditions, samples of balsa wood were incubated with the fungus for a period of three months to achieve maximum luminosity. During this incubation, the wood absorbed a significant amount of moisture, increasing its weight by as much as eight times as it became fully permeated by the fungus.
Selective Decomposition for Stability
A crucial aspect of the process is the fungus’s selective decomposition of wood components. Using techniques including spectroscopy and X-ray diffraction, the researchers observed how Desarmillaria tabescens breaks down lignin, the natural polymer that gives wood its rigidity. However, the analyses confirmed that the fungus leaves the wood’s cellulose structure completely intact. Since cellulose is responsible for the wood’s tensile strength and stability, the resulting biohybrid material retains its core structural properties, including stiffness and compressive strength.
The Science Behind the Glow
The bioluminescence of the wood is not a simple coating but an active biological process. The honey fungus naturally produces a light-emitting compound called luciferin. This substance is stimulated to glow through a two-stage enzymatic reaction. The team succeeded in inducing and controlling this reaction within the laboratory setting.
The glowing process is triggered when the fungus-infused wood comes into contact with air, which initiates the enzyme activity. While the reaction begins upon air exposure, it takes approximately 10 hours for the bioluminescence to build and unfold its full splendor, allowing the material to reach its peak brightness.
Properties of the Luminous Biomaterial
The final product is a composite material with unique optical and mechanical characteristics. Its development represents a successful proof of concept for creating functional, living biomaterials that maintain their essential wood-like structure.
Optical Characteristics
The biohybrid wood emits a gentle, greenish light with a measured wavelength of 560 nanometers. The intensity of the glow is currently modest, described as being comparable to the light from a single candle. Under the current laboratory parameters, the fascinating glowing effect lasts for approximately 10 days before fading as the biological process ceases.
Structural Durability
Despite being thoroughly colonized by a fungus known to cause rot, the wood does not lose its valuable mechanical properties. The preservation of the cellulose scaffold ensures that the material remains strong and stable. This durability is a key achievement, making the luminous wood a viable material for practical use rather than just a scientific curiosity.
Future Applications and Research
The primary motivation for this research is to elevate wood from a simple fuel source to a high-value, functional material. This aligns with sustainability goals by finding innovative uses for resources like Swiss hardwood that are often underutilized. The successful creation of luminous wood opens the door to a range of potential applications where gentle, ambient light is desired.
Potential uses could include unique designer furniture, glowing jewelry, architectural details, or ambient, eco-friendly lighting for interior spaces. The project demonstrates one of many possibilities for creating advanced biomaterials, with other research efforts exploring how to make wood magnetic, waterproof, or even capable of generating electricity. The team is now focused on refining its methods to enhance the properties of the glowing wood. Empa researcher Giorgia Giovannini stated that they are optimizing laboratory parameters to further increase the luminosity and extend the duration of the glow in the future.
