Swiss scientists have created a new plastic-like material that’s flexible, biodegradable, and even edible. The secret? It’s still alive.
The material, which was created by a team from Empa in Switzerland, manages to balance biodegradability with toughness and versatility – a feat that is far from easy in materials science.
The researchers processed fibers from the mycelium (the root-like part) of the split-gill mushroom (Schizophyllum commune) into a liquid mixture, without actually killing them off or destroying their natural biological functions.
The resulting gel-like material is called living fiber dispersions, or LFD, and it can be molded into many different forms. It also makes full use of the extra substances produced by mushrooms, where other biomaterials might just use the core fungal cells.
“The fungus uses this extracellular matrix to give itself structure and other functional properties,” says materials scientist Ashutosh Sinha, from Empa. “Why shouldn’t we do the same?”
By developing a specific strain of the split-gill, the researchers were able to encourage the growth of two molecules in particular: polysaccharide schizophyllan and hydrophobin. These molecules are crucial in giving LFD its appealing properties.
One possible use of the material is as a thin film with a very high tensile strength. The researchers suggest it could potentially be used in compost bags that naturally rot away as well as composting their contents, or in super-thin biodegradable batteries.
LFD also works well as an emulsifier, a substance that enables two other materials to mix and bind together when they otherwise wouldn’t. Emulsifiers are important in food and cosmetics production, found in everything from ice cream to shampoo.
Because it’s still alive, the fungus keeps releasing more of its key molecules.
“This is probably the only type of emulsion that becomes more stable over time,” says Sinha.
And because it comes from the edible S. commune mushroom, this LFD is completely non-toxic too – you can even eat it without any problems. When it comes to foods and cosmetics, that’s another big plus for the material.
There’s the potential for plenty of future research here too, because the team thinks that the approach used here could be tweaked to produce materials with other specific properties, like an on-demand materials maker.
Scientists will often look to nature for inspiration, whether they’re developing drug delivery methods or building robots, and we’re seeing an increasing number of studies investigating fungi as a foundation for new materials.
Fungi-based biomaterials could act as alternatives to plastic, and to form clothes that are able to repair themselves. There’s a lot of benefit in materials that combine the natural and the synthetic.
The researchers are hoping to find more and more practical uses for LFD over time, following in a long line of materials inspired by nature – evidence that the natural world around us is the best lab there is.
“Biodegradable materials always react to their environment,” says materials scientist Gustav Nyström, from Empa.
“We want to find applications where this interaction is not a hindrance but maybe even an advantage.”
The research has been published in Advanced Materials.
