The clinical problem the work targets is a familiar one in dentistry. Periodontal and peri-implant diseases destroy the alveolar bone that anchors teeth and implants, and rebuilding that bone remains one of periodontology’s hardest challenges. Guided bone regeneration, or GBR, addresses it by placing a barrier membrane over a bone defect so that fast-moving soft-tissue cells cannot invade the wound while slower osteoblasts repopulate the site and lay down new bone. Current membranes force a trade-off. Non-resorbable options such as polytetrafluoroethylene and titanium are mechanically excellent but require a second surgery to remove. Resorbable collagen membranes are more biocompatible but degrade quickly and lack strength, especially in the wet, microbe-laden environment of the mouth.

Fungal mycelium offered the researchers a way out of that trade-off. A mycelium is a dense, self-assembling network of hyphae that acts as a natural bio-adhesive, binding substrate particles together as it grows. It is intrinsically porous, a critical property for scaffolds because interconnected pores deliver nutrients and oxygen to cells and carry away waste. It is also naturally hydrophobic, thanks to mannoproteins and hydrophobins in the outermost fungal cell wall, and its chitin-containing matrix has been shown in earlier studies to promote hydroxyapatite deposition and support wound healing. The Ganoderma genus brings an additional bonus: a rich repertoire of bioactive metabolites, from polysaccharides to the immune-modulating protein LZ-8, whose components appear to work synergistically, which is why the team used the intact mycelium rather than extracted molecules.

Manufacturing the material was conceptually simple. The researchers prepared a solution of alginic acid fortified with malt extract, yeast extract and sucrose as fungal nutrients, dried it into a membrane, and immersed it in a calcium chloride bath containing hydroxyapatite nanoparticles at concentrations of 0, 1.1, 4.4 or 8.8 percent. Calcium ions crosslinked the alginate chains around the mineral particles, producing a sterilized culture substrate. A small square of G. sessile mycelium was then inoculated onto each hydrogel and incubated at 25 degrees Celsius in the dark. Photographic monitoring showed that colonization progressed at essentially the same pace on every substrate, with full coverage achieved by day twelve regardless of mineral content, suggesting the hydroxyapatite does not impede fungal growth.

A biomaterial destined for the body must be sterile and biologically inert, so the team froze the colonized membranes, freeze-dried them, and autoclaved them at 120 degrees Celsius for twenty minutes to kill the fungus. The treatment worked: when fragments were re-cultured on nutrient agar for sixty days, no growth appeared. Transmission electron microscopy of cross-sectioned hyphae confirmed the loss of cellular integrity, but with a striking qualification. The thickness of the hyphal cell walls was statistically unchanged by autoclaving, measuring roughly 77 nanometers before and after treatment, meaning the fungal cell wall scaffold survived sterilization intact even though the living contents did not. Macroscopically, the finished membrane shrank by about 21.7 percent in covered area but retained its shape, flexibility and ease of handling.

Structural analysis revealed why the material is so unusual. X-ray diffraction confirmed the presence of the synthetic hydroxyapatite, but it also detected something the researchers had not put there: calcium oxalate dihydrate crystals, which the fungus itself had precipitated from the calcium-rich medium. Ganoderma species are known to produce such crystals as a calcium reservoir, and remarkably, calcium oxalate surfaces serve as common binding sites for bone proteins such as osteopontin, which promotes osteoblast adhesion and migration. That raises the tantalizing possibility that the fungal crystals could act as anchoring points for bone proteins and even as nucleation sites for new hydroxyapatite formation inside the body. Scanning electron microscopy then showed the composite’s most compelling feature: where the mycelium had colonized the substrate, it had built a porous, hierarchical, trabecular network strikingly similar to spongy bone.

The membrane’s two faces behave almost oppositely toward water. The mycelium-rich side, studded with hydrophobic fungal proteins and covered in micrometer-scale roughness, produced a water contact angle of about 143 to 148 degrees, well into strongly hydrophobic territory. The alginate-rich side measured roughly 36 to 38 degrees, clearly hydrophilic. This anisotropy could be a design advantage rather than an accident: hydrophobic surfaces tend to resist bacterial adhesion and lend mechanical stability, while hydrophilic surfaces favor protein adsorption, cell attachment and nutrient exchange. A membrane that presents a bacteria-repelling face to the soft tissue and a cell-friendly face to the bone defect would create a more biomimetic microenvironment than any uniform material.

Mechanical testing of the lead composition, My-ALG-1.1HA, added further encouragement. Stress-strain curves showed an elastic region, a yield point and a long plastic plateau, confirming a ductile material that absorbs substantial energy before failing. The Young’s modulus came out at 25.28 megapascals, squarely within the reported range for human oral mucosal tissue of roughly 2.2 to 54.7 megapascals, although the maximum tensile stress of 0.32 megapascals remains below oral tissue values. Notably, the ductility exceeded that of previously reported mineralized mycelium materials, and the same hydroxyapatite loading that made the team’s earlier alginate-hydroxyapatite membranes brittle seemed masked by the mycelium framework. Degradation testing in simulated body fluid was equally telling: the composite lost about 49.7 percent of its weight in the first day, but the presence of fungal molecules slowed overall degradation roughly 380 percent relative to the corresponding alginate-hydroxyapatite membrane without mycelium, plausibly because mycelium-derived compounds raise hydrophobicity and shield the hydrogel from dissolution.

A first biological screen was cautiously reassuring. The researchers ground each biomaterial into powder, extracted it into cell culture medium at one milligram per milliliter, and exposed MC3T3-E1 osteoblast-like cells to the dispersions for 48 hours. Optical microscopy showed normal cell size, shape and spreading, and a crystal violet assay found no statistically significant reduction in attached cells for any formulation, including those with hydroxyapatite at 1.1, 4.4 and 8.8 percent. The authors are careful to frame this as a preliminary, indirect assessment rather than proof of osteogenic performance. They also stress the limits of the current dataset: contact angle and tensile measurements were not taken for the higher-mineral compositions, comparisons with oral tissues involve differing test geometries, and wet-state stability and suture retention still need optimization, potentially through higher crosslink density, secondary covalent networks or alginate-chitosan complexes.

Even with those caveats, the study stakes out genuinely new territory. Where most mycelium materials have been explored for packaging, construction or skin wound dressings, this work positions intact Ganoderma mycelium as a structure-directing biological framework inside a mineralized composite engineered for the mouth. Future work must move from indirect assays to direct osteoblast culture on the intact anisotropic surfaces, and on to alkaline phosphatase activity, osteogenic marker expression and mineralization, before the membrane can approach the clinic. But the core demonstration stands: a mushroom can be persuaded to grow, on demand, into a sterile, ductile, bone-like scaffold whose chemistry, topology and degradability are shaped by a living organism. If subsequent studies confirm that the fungal framework and its bioactive cargo can outperform collagen barriers in the demanding environment of a periodontal defect, the humble mycelium may earn a permanent place in the surgeon’s toolkit.

Subject of Research: A mycelium-alginate-nanohydroxyapatite composite biomaterial for guided bone regeneration

Article Title: Characterization of a novel biomaterial obtained by culturing Ganoderma sessile on a substrate composed of hydroxyapatite nanoparticles and alginate with potential for bone tissue regeneration

Article References: D’Elía, N. L., Postemsky, P., Sartuqui, J., Placente, D., Gonzalez-Pardo, V., Ercoli, D., & Messina, P. V. (2026). Characterization of a novel biomaterial obtained by culturing Ganoderma sessile on a substrate composed of hydroxyapatite nanoparticles and alginate with potential for bone tissue regeneration. Frontiers in Biomaterials Science, 5, Article 1895818. https://doi.org/10.3389/fbiom.2026.1895818

Image Credits: AI Generated

DOI: 10.3389/fbiom.2026.1895818

Keywords: Ganoderma sessile, mycelium, hydroxyapatite nanoparticles, alginate, guided bone regeneration, bone tissue engineering, biomaterials, periodontal regeneration, hydrophobicity, cytocompatibility, calcium oxalate, barrier membranes