Sea Coral in Bone Grafting? How the Material is Made Compatible with Natural Bone

When you think of bone grafting, you probably don't think of sea coral. Yet scientists have now discovered a way to refine the materials' properties that may make it more compatible with natural bone. This, in turn, could lead to better treatments in the future.

"When biomaterials do not biodegrade and remain in skeletal tissue, they may continuously cause problems in the host," said Zhidao Xia, one of the researchers, in a news release. "In extreme conditions, it is possible that the different mechanical properties of the artificial bone graft may cause a re-fracture or become a source for bacterium growth in infection."

In order to get around this issue, the researchers decided to study the calcium carbonate found in the exoskeleton of sea coral and convert it into coralline hydroxyapatite (CHA). They then refined the material to produce coralline hydroxyapatite/calcium carbonate (CHACC). This CHACC composition contained 15 percent of CHA in a thin layer around the calcium carbonate and had a strong, porous structure that has made CHA commercially successful, but contained significantly improved biodegrading properties to support natural bone healing.

"Our methods have considerably improved the outcome of bone grafts by using the partial conversion technique, in which the biodegradable composition from natural coral is reserved," said Xia in a news release. "It works in a very similar way to commercially available CHA for conductive bone regeneration, but the better biodegradation properties are compatible with the host tissue's natural bone turnover process."

That's not to say that the material is ready to be used across the globe. There is a ways to go before the material can match the benefits of an autograft and can be used by the several million people worldwide that undergo bone grafting procedures each year. Even so, the development of the CHACC material could provide an important step toward creating a biodegradable material that could help patients in the future.

The findings are published in the journal Biomedical Materials.