Fungi are vital to natural ecosystems by breaking down dead organic material and cycling it back into the environment as nutrients. But new research from the University of Utah finds one species, Marquandomyces marquandii, a ubiquitous soil mold, shows promise as a potential building block for new biomedical materials.
In recent years, scientists have examined fungal mycelium, the network of root-like threads—or hyphae—that penetrate soils, wood and other nutrient-bearing substrate, in search of materials with structural properties that could be useful for human purposes, particularly construction.
In a series of lab demonstrations, U mechanical engineering researchers and biologists show M. marquandii can grow into hydrogels, materials that hold lots of water and mimic the softness and flexibility of human tissues, according to a recent study.
Unlike other fungi that struggle with water retention and durability, M. marquandii produces thick, multilayered hydrogels that can absorb up to 83% water and bounce back after being stretched or stressed, according to Atul Agrawal, the lead author of the study. These properties make it a good candidate for biomedical uses such as tissue regeneration, scaffolds for growing cells or even flexible, wearable devices.
“What you are seeing here is a hydrogel with multilayers,” said Agrawal, holding a glass flask containing a fungal colony growing in a yellowish liquid medium. “It’s visible to the naked eye, and these multiple layers have different porosity. So the top layer has about 40% porosity, and then there are alternating bands of 90% porosity and 70% porosity.”
Looking to nature to innovate materials
Agrawal is a Ph.D. candidate at the John and Marcia Price College of Engineering. His paper is the latest to emerge from the lab of senior author Steven Naleway, an associate professor of mechanical engineering who explores biological substances to develop bioinspired materials with structural and medical applications.
Agrawal and Naleway are seeking patent protection for their discoveries about the Marquandomyces fungus.
“This one in particular was able to grow these big, beefy mycelial layers, which is what we are interested in. Mycelium is made primarily out of chitin, which is similar to what’s in seashells and insect exoskeletons. It’s biocompatible, but also it’s this highly spongy tissue,” said Naleway, whose lab is funded by the National Science Foundation. “In theory, you could use it as a template for biomedical applications or you could try to mineralize it and create a bone scaffolding.”
Fungi comprise its own kingdom of organisms, with an estimated 2.2 to 3.8 million species, and just 4% have been characterized by scientists. For decades, scientists have derived from fungi numerous pharmacological substances, from penicillin to LSD. Naleway is among a cohort of engineers now looking to fungal microstructures for potential use in other arenas.
Why fungal mycelia have interesting mechanical properties
In collaboration with U mycologist Bryn Dentinger, Naleway’s lab has produced a string of papers documenting potentially useful structural properties of various species of fungi. One outlined how fungi that grow short hyphae are more stiff than those that grow longer hyphae. Another catalogued the various ways bracket fungi’s high strength-to-weight ratios make them a viable alternative in various applications, including aerospace and agriculture.
The way fungal hyphae grow is the reason why mycelia could have useful structural properties.