Regenerative Medicine

Sheep's Wool Helps Regrow Bone — Keratin Outperforms Collagen Scaffolds

Keratin pulled from sheep's wool was used to grow new bone in animals, and the resulting tissue was more organized and structurally closer to healthy bone than anything the same team had produced with the collagen scaffolds surgeons rely on today.

• Keratin extracted from sheep's wool served as the scaffold — the structural frame a new tissue grows into — for bone repair experiments in animals.
• New bone grown on the wool-keratin scaffold was more orderly and structurally similar to natural healthy bone than bone grown on conventional collagen scaffolds.
• The material is abundant, biodegradable and derived from a by-product of the wool industry, which makes it far cheaper and easier to source than many proprietary biomaterials currently used in clinics.

When bone is damaged badly enough that it cannot heal on its own — after a severe fracture, a tumor removal, or a non-union wound — surgeons implant a scaffold. The scaffold is a temporary structure that guides the body's own cells to grow new bone into the gap. Most scaffolds on the market are made of collagen, the structural protein already found in bone and connective tissue. Collagen works, but the new bone that forms on it tends to be messy: more porous, less ordered, and weaker than the surrounding healthy tissue.

A team has now tested a different scaffold material: keratin extracted from sheep's wool. Keratin is the structural protein in hair, wool and nails. It is mechanically strong, readily biodegradable in the body, and — as a by-product of the global wool industry — essentially free to produce in large quantities.

The experiments compared new bone grown on wool-keratin scaffolds against bone grown on collagen scaffolds, using the same defects in the same animal models. The keratin scaffolds produced bone that was more orderly, with a finer, more regular structure that closely resembled healthy native bone. Collagen scaffolds, by contrast, produced tissue that was patchier and structurally looser.

Why keratin may do better is not fully settled, but several factors line up. Keratin fibers form denser, more interconnected meshes than most collagen preparations, giving bone-forming cells a more natural geometry to grow along. Keratin is also chemically more stable than collagen during processing, which means less loss of structure before the scaffold ever reaches the patient. And because the material is cheap and abundant, it is possible to design many scaffold variants without worrying about cost per unit.

The result is still a pre-clinical finding — the work was done in animals, not humans — but it is a meaningful shift for a field that has relied on collagen for decades. A cheaper, biodegradable material that produces better bone structure could eventually change what surgeons use in fracture repair, spinal fusion and tumor-resection reconstruction, where scaffold quality directly determines recovery.