Beneath the forest floor lies a vast, interconnected network often described as nature’s underground Internet. It is called the mycelium. Composed of millions of microscopic, thread-like strands called hyphae, this fungal biological network is ubiquitous. When we see mushrooms pop up, they are the above ground fruit of the mycelium network.
Recent research has revealed that trees feed each other, especially their own kind, through these fungal networks. The fungi are connected to the trees’ roots, and they form a symbiotic relationship. The fungi supply the trees with carbon and mineral nutrients, while the trees “pay” for this by giving them up to 30% of the sugar that they photosynthesize from sunlight. The fungi use what they need and transfer the rest to other trees through their network.
This mycelium network connects to all trees in the forest. Mature, healthy trees feed smaller trees, especially saplings that do not get enough sunlight to manufacture their own sugars. The network also feeds trees that are unhealthy. The small saplings that we see in a forest may be very old, some as old as 80 years, biding their time until the older trees die.
But there is even more to this network than its role in the forest. Today, researchers are leveraging mycelium and its fungal bioengineering to address two of medicine’s challenges: the global crisis of drug-resistant pathogens and the critical shortage of human tissues for transplantation.
In their natural soil habitats, fungi live in competition with millions of bacteria, viruses, and competing fungi. Lacking physical mobility or immune systems, fungi survive entirely through biochemical defense. They secrete complex specialized chemical weapons engineered to destroy bacteria, disrupt viruses, and inhibit enemy growth.
Recent research uncovers that fungal species harbor tens of thousands of dormant genetic sequences capable of producing novel antimicrobial molecules. By activating these genes in laboratory settings, biopharmaceutical researchers are discovering new classes of compounds capable of defeating multidrug-resistant bacteria like MRSA (Methicillin-resistant Staphylococcus aureus).
Fungi may also help in the development of antiviral medications. Wood-decay fungi, such as reishi and bracket fungi, produce unique compounds that inhibit viruses, offering potential solutions for novel antiviral therapies.
While the chemical output of fungi is assisting pharmacology, their physical structure is transforming tissue engineering.
To understand how valuable fungi physical structure is, it is important to understand the issue that laboratories face. Lab-grown human tissues, organs, or muscle fibers, biomedical engineers require a porous, three-dimensional matrix like a scaffold that gives human cells a structural framework to cling to, divide, and receive nutrients. Traditional scaffolds are made of synthetic polymers or animal-derived collagen and can be prohibitively expensive, difficult to manufacture at scale, or prone to triggering immune rejection.
But mycelium may be a solution. Fungi are a unique evolutionary organism, sharing a closer genetic relationship to animals than to plants. This means their biochemical pathways are compatible with human biological innovations.
As mycelium grows through organic substrates (like soil, agricultural waste or sawdust), it forms a dense, three-dimensional network of microfibers. Scientists can control the density, porosity, and shape simply by altering the growth environment and mold geometry.
These processed mycelial scaffolds are non-toxic, structurally stable, and naturally porous. They allow nutrients and oxygen to flow freely to growing human cells, solving one of tissue engineering’s biggest hurdles: creating functional pathways for blood and fluid exchange.
Researchers are currently testing scaffolds where the fungal living cells are removed, leaving behind only the inert fibrous shell. They are using them to culture cardiac tissue, skin grafts, and bone structures. This approach offers an eco-friendly, highly scalable, and compatible alternative to synthetic materials.
Mycelium is proving that the solutions to some of humanity’s most complex medical challenges may have been mysteriously beneath our feet all along.