Scientists use mushrooms to make biodegradable computer chips

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Foraging for fungi may not just mean mushrooms are on the menu. New research has shown that mushroom shells may provide a biodegradable alternative to some plastics used in batteries and computer chips, making them easier to recycle.

Researchers at Johannes Kepler University in Austria were working on flexible and stretchable electronics, with a focus on sustainable materials to replace non-degradable ones, when they made their discovery, published in the journal Science Advances Friday.

“There was a fair amount of serendipity involved,” Martin Kaltenbrunner, chief of the university’s Department of Soft Matter Physics and co-author of the paper, told CNN.

At the time, a member of the team had looked into using fungi-derived agents materials for use in other areas. This work led to the latest study, which shows how Ganoderma lucidum mushroom skin could work as a substitute for the substrate used in electrical circuits.

A substrate is the basis of a circuit that insulates and cools the conductive metals sitting on top of it. Usually they are made of non-degradable plastics, which are thrown away after use.

The team, led by Doris Danninger and Roland Pruckner of the university’s Institute for Experimental Physics, found that the mushroom — which typically grows on decaying hardwood trees in Europe and East Asia — forms a compact protective skin made of mycelium, a root-like network, to protect its growing medium (the wood).

The researchers created proximity and humidity sensors to test the mycelium battery.

“They do this to protect themselves from the entry of other fungi or bacteria,” said Kaltenbrunner, explaining that the team was able to reap this insulating protection by using the skin and dries it out.

According to the research paper, the skin is slightly less insulating than plastic, but it still worked safely and successfully in the electrical circuits, with a thickness similar to paper and the ability to withstand temperatures in excess of 200° Celsius (392° Fahrenheit), making it a good substrate.

The hide has many properties that set it apart from other biodegradable materials, Kaltenbrunner said, “but most importantly, it can be easily grown from waste wood and requires no energy or cost-intensive processing.”

“Our mycelium is kind of a sweet spot because it lasts a long time if kept dry, but in just a standard household compost it would break down completely in two weeks or less,” he added.

While the team’s work is currently experimental and a long way from mass production, they believe the biodegradable skins could provide a sustainable alternative material for use in electronics that don’t require long-lasting electrical circuits, such as wearable health monitors and NFC (Near Field Communication) tags for electronic devices.

But they are also considering wider use if they can control the growth of the mycelium so that it is uniform and reproducible.

There are large amounts of waste wood, such as wood chips from industrial saws, Kaltenbrunner told CNN, which is a lot of food for mushrooms.

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