Synthetic Graft Expedites the Repair of Bone Defects

An easy-to-produce, inexpensive, synthetic bone material could be a potential replacement for current bone transplantations.

Developed by researchers at the University of Massachusetts (UMass; Worcester, USA), FlexBone is a nanocrystalline hydroxyapatite structurally integrated with a crosslinked Poly[2-hydroxyethyl methacrylate] (pHEMA)hydrogel, which provides dimensional stability and elasticity. It recapitulates the essential role of nanocrystalline hydroxyapatite in defining the osteoconductivity and biochemical microenvironment of bone, due to its affinity for biomolecules. FlexBone has a bone mineral content approaching that of human bone, enabling the elastic material to be cut and shaped prior to surgery or intra-operatively, and then pressed into a bone gap.

The density of the material also allows surgeons to pre-drill channels in it, allowing for bone marrow from adjacent bone to migrate and penetrate, thus attracting progenitor cells that are critical to new bone formation. FlexBone absorbs and retains the proteins associated with the natural healing process from the surrounding tissue once implanted; it can also be loaded with therapeutic agents, such as protein factors and antibiotics that can facilitate faster healing and fight infection through localized and controlled delivery over a sustained period of time. The study describing Flexbone was published ahead of print on October 21, 2010, in Tissue Engineering Part A.

"Because of this combination of factors, our study shows that FlexBone, combined with a protein growth factor in a dose 100 times less than what currently needed, was able to heal a large, long bone defect that would not heal on its own in a short period of time,” said lead author Jie Song, Ph.D., an assistant professor of orthopedics, physical rehabilitation, and cell biology. "This material has enormous potential to solve a major problem that orthopedic surgeons face when reconstructing large bone deficits in the skeleton.”

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