(Nanowerk Spotlight) Circuit boards form the foundation of modern electronics, but their production relies on materials that persist in the environment for centuries. These boards must meet precise technical requirements: perfectly smooth surfaces for mounting components, specific electrical properties to carry signals without interference, and the ability to withstand intense heat during assembly. Creating alternatives that decompose naturally while meeting these strict standards has challenged researchers for decades.
Initial attempts at biodegradable electronics failed to match even basic requirements. Plant-based materials warped under heat. Bio-plastics couldn’t achieve the necessary electrical properties. Natural fibers proved too rough and irregular for precise circuit patterns. Each alternative solved one challenge while falling short on others, leading many to conclude that environmental sustainability would require compromising performance.
A research team at Johannes Kepler University in Linz, Austria, has now disproven this assumption by transforming fungal tissue into circuit boards that match conventional materials in performance while decomposing completely after use. Their approach targets the fundamental properties of the material rather than trying to replicate traditional manufacturing processes.
The researchers selected Ganoderma lucidum, a fungus that grows on dead hardwood, harvesting its root structure (mycelium) before it matures. This timing prevents the formation of tough outer layers that would interfere with processing. They then developed a precise chemical treatment sequence using sodium hydroxide and acetic acid that fundamentally alters the cellular structure of the material.
This treatment collapses the fungal networks into a dense, uniform material with a surface roughness of 2.7 micrometers. The process also reduces the material’s electrical conductivity by a factor of 100 compared to untreated fungal tissue, preventing electrical signals from bleeding between circuits – a crucial requirement for reliable electronic function.
Eco-friendly fabrication ofmycelium-based substrates for electronic circuits. Following the harvest of the pure mycelium skin grown on agricultural wastes, chitin-deacetylase with sodium hydroxide and acetic acid extracts valuable chitosan from the mycelium leaving behind a collapsed hyphae structure with enhanced mechanical and electrical properties. By implementing reversible surface functionalization methods, the lifetime of the skin is extended via an optional sub-cycle. At the end-of-life it biodegrades, starting the cycle from anew. All possible by-products of the cultivation process, such as the mycelium-infused medium and its fruiting bodies, are still useful afterward as packaging material and in medicine. Scale bar, 10 μm. (Image: Reprinted from DOI:10.1002/adfm.202412196, CC BY)
The treated material withstands temperatures up to 250 degrees Celsius without degrading, allowing manufacturers to use standard soldering techniques for attaching components. Traditional circuit boards typically require similar temperature resistance for reliable assembly.
To protect the material during use, the researchers applied a coating of shellac – a natural resin secreted by lac bugs. This coating serves three crucial functions: it prevents moisture absorption that would disrupt electrical signals, provides an adhesive layer for copper circuit components, and enables end-of-life recycling. When submerged in ethanol, the shellac dissolves, allowing recovery of valuable metals while the fungal material composts naturally.
The team demonstrated their material’s practical viability by manufacturing a near-field communication (NFC) tag – a complex electronic device requiring precise circuit patterns. The tag remained functional after four months of storage in normal conditions, proving the material maintains its properties over time.
Testing showed that discarded circuit boards made from this material lose over 90% of their mass within ten days in composting conditions, while allowing complete recovery of metal components for reuse. This rapid decomposition contrasts sharply with conventional circuit boards, which can leach harmful compounds into soil and groundwater for decades.
The manufacturing process also offers environmental advantages beyond end-of-life handling. It uses agricultural waste as raw material and requires minimal energy input compared to traditional circuit board production. The chemical treatments produce useful byproducts – the extracted fungal compounds have applications in medicine and food production.
This development demonstrates that electronics can be designed for their entire lifecycle without sacrificing performance. The fungal-based circuit boards match the technical specifications of conventional materials while enabling complete recycling or decomposition of every component. This approach provides a template for redesigning other electronic components with environmental sustainability as a core feature rather than an afterthought.
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