Scientists from King’s College London turned an agricultural waste product into a bone-healing scaffold; keratin from sheep’s wool produced more natural-looking regenerated bone than collagen in animals

A material that begins as sheep’s wool has now shown an ability to help damaged bone rebuild itself inside a living animal. The surprising part is not simply that wool can be turned into a medical material. It is that keratin extracted from the fibre produced new bone with a more organized architecture than tissue formed using a conventional collagen membrane.

The finding points to an unusual possibility: an agricultural byproduct could become a useful ingredient in regenerative medicine. The research was carried out by scientists at King’s College London and published in Biomaterials Advances in 2026. The team developed membranes from keratin extracted from wool and chemically stabilized them so they could remain intact during healing.

The material was then tested first with human bone marrow stromal cells and later in rats carrying critical-size defects in the skull. These defects were large enough that they would not normally repair themselves completely, creating a demanding test for a bone-regeneration material.

Why wool keratin could help damaged bone regrow

Keratin is a structural protein found throughout nature. In sheep’s wool, it forms the tough protein framework that gives each fibre its strength and resilience. That same biological material has properties that make it interesting to researchers working on tissue engineering. Instead of treating wool as something useful only for textiles, scientists can extract its keratin and process the protein into a membrane designed to interact with cells and tissues.

The goal here was not to replace missing bone with a piece of wool. The keratin membrane acts as a temporary environment around the injury, helping control what happens while the body rebuilds the damaged tissue. This approach is known as guided bone regeneration, or GBR. A barrier membrane can prevent rapidly growing soft tissue from occupying a space that needs to remain available for bone-forming cells and new bone to develop.

That distinction matters because successful bone regeneration is not simply about producing more tissue. The new tissue must also develop an appropriate structure. Bone has a highly organized architecture, with collagen fibres and mineral components arranged in ways that give it strength. A regenerative material therefore needs to do more than keep a wound covered. Ideally, it should create conditions that encourage cells to build tissue in a coordinated way.

Scientists tested Keratin on human bone cells

The researchers began outside the animal, using primary human bone marrow stromal cells to examine how the keratin membranes interacted with bone-forming cells. The cells showed high viability on the material and progressed through stages associated with osteogenic differentiation, meaning they developed characteristics linked to bone formation. The researchers also observed increased expression of markers associated with both early and later stages of osteogenesis.

This was an important step because a scaffold can look promising as a material but still fail biologically. Cells have to attach to it, survive and respond appropriately to its surface and surrounding chemical environment. In this case, the keratin membrane behaved more like a biologically active substrate than a completely passive barrier. That finding helped justify moving the material into an animal model.

The team then created critical-size defects in the calvarial bones of rats. The calvarium is the portion of the skull that surrounds and protects the brain. A critical-size defect is deliberately large enough that spontaneous healing is limited, allowing researchers to determine whether a treatment is actually contributing to regeneration rather than simply accelerating a repair process that would have happened anyway.

The Keratin scaffold did something unexpected

The results produced an important nuance that is easy to lose in a simple headline. The keratin membrane did not produce a greater total amount of new bone than the collagen membrane. In fact, the collagen group generated a higher overall bone volume. But the keratin-treated defects showed a different advantage: the new bone and its collagen architecture were more spatially organized.

That difference is scientifically significant. Bone is not merely a pile of newly produced material. Its microscopic organization influences how it develops and performs mechanically. The researchers reported that tissue formed with the keratin scaffolds had a more organized architecture and better-aligned structural features that more closely resembled healthy bone. The membrane also supported bridging across the defect and integrated with surrounding soft tissue during healing.

The researchers believe this behavior may come from the way the keratin membrane interacts with cells during regeneration. The material was stabilized through intrinsic protein interactions and controlled crosslinking, giving it greater structural stability while retaining biological activity. Rather than simply covering the defect, the scaffold appeared capable of providing a surface that supported coordinated bone formation and tissue maturation.

Why Collagen has been the standard for so long

Collagen has played a central role in guided bone regeneration for decades because it is a natural component of connective tissue and can provide a temporary barrier during healing. Collagen membranes are already used in dental and regenerative procedures, where controlling the movement of soft tissue can be essential for successful bone repair. Their biological familiarity has made collagen an attractive material for medical scaffolds.

But collagen also has limitations. It can be relatively weak and may resorb before a difficult defect has had enough time to stabilize. That becomes particularly important when regeneration takes place in larger or mechanically demanding areas. The extraction and processing of collagen can also be complicated, while its biological properties can vary depending on how the material is sourced and prepared.

Keratin offers a different set of characteristics. Wool is already produced at enormous agricultural scale, and much of it can have limited economic value or be treated as waste. Turning that material into a refined biomaterial could therefore create a second use for a renewable resource. The researchers describe keratin as potentially scalable as well as structurally stable and biologically active.

From Sheep’s wool to a medical Scaffold

The transformation from wool fibre to bone-regeneration membrane involves more than simply dissolving wool and placing the protein over an injury. Keratin has to be extracted and processed into a form that can survive in a biological environment. The King’s College London team chemically treated the extracted protein and used controlled crosslinking and protein interactions to create stable membranes. That processing is important because a regenerative scaffold must remain functional long enough to support the early stages of tissue repair.

The resulting membrane was designed around the principles of guided bone regeneration. It needed to provide a protected space for bone formation, remain stable during healing and interact favorably with surrounding biological tissue. The animal results suggested that it could meet several of these requirements. Researchers observed soft-tissue integration, bridging of the bone defect and organized new bone formation.

This is where the discovery becomes more than an unusual example of recycling. A material that begins in an agricultural waste stream could potentially be engineered at the molecular level for a medical purpose. The same protein responsible for the physical properties of wool can be reorganized into a scaffold that influences how cells behave around an injury. That is a very different way of thinking about farm waste.

The study is promising, but it is not yet a human treatment

The results should not be interpreted as evidence that sheep’s wool can currently be implanted into people to regrow missing bone. The research has reached an important preclinical milestone, but the successful animal experiment is still far removed from routine clinical use. Human safety, long-term stability, manufacturing standards, immune responses and performance in different types of bone defects would all need to be established before such a material could become a medical product.

There is also an important question about where the material works best. The current study focused on rat skull defects, not large weight-bearing bones such as the femur or tibia. Skull bone has different biological and mechanical demands from the bones that carry body weight. The researchers therefore have more work to do before it is clear whether keratin membranes can perform effectively in more demanding orthopedic applications.

Still, the study changes the conversation around keratin-based biomaterials. The material did not simply survive inside a living animal. It supported regeneration and produced tissue with a degree of structural organization that compared favorably with conventional collagen scaffolds, even though collagen generated more total bone volume in the experiment. That distinction gives researchers a new question to investigate: whether better organization could ultimately matter as much as the amount of bone produced.

For now, the sheep’s wool discovery is best understood as a promising step in regenerative medicine rather than a finished therapy. The research shows that keratin can be converted from an abundant natural protein into a stable, biologically active membrane capable of supporting bone repair in an animal model. If future studies confirm its safety, durability and effectiveness, an everyday agricultural material could eventually become part of a much more sophisticated medical technology.

Source note: The underlying peer-reviewed study is Sara Gamea and colleagues, “Bone regeneration of rat calvarial defect using biomimetic keratin-based membranes,” published in Biomaterials Advances, volume 184, article 214806, in 2026.