Why is it so hard to grow bone in the lab?

THAT'S THE WHY:THE BONES that make up your skeleton are pretty impressive. Rather than being simply inert structures, they consist of living, dynamic tissue, and when bone is damaged a little it can self-heal remarkably well. But if there's a lot of damage or a large fracture you may need a bone graft, which uses bone tissue from elsewhere in your body or from a donor, or else synthetic bone substitutes to plug the gap.

But why not just grow replacement tissue in the lab? It’s not as easy as it sounds, explains Prof Fergal O’Brien, who heads the Tissue Engineering Group at the Royal College of Surgeons in Ireland.

“Due to the complexity of the tissue and the numerous cell types that are found within it, growing bone in the lab is a difficult task,” he says. “In addition, unlike other tissues, the engineered bone tissue needs to be able to bear mechanical load while healing is taking place.”

The tissue you grow in the lab has to have the desired effect once it is placed in the body, and it particularly needs to encourage the growth of a blood supply to support it, he adds.

“So the next generation of tissue engineered constructs are focusing on developing smart biomaterials which don’t need to be cultured with cells in the lab, they have the potential to recruit the body’s own cells and to attract blood vessels to speed up the repair process.”

O’Brien’s group has developed such a material, called HydroxyColl, and spin-out company SurgaColl is now looking to bring it to the clinic.