This Sponge Could Help Fill Gaps Where Bone Can't Regrow Itself

Your bones are masterful self-healers, but certain injuries and defects can leave a gap too wide for new bone cells to fill in. Texas A&M's Dr. Melissa Grunlan and team have come up with a solution, a biodegradable polymer sponge that supports new bone cell growth, then disappears as it's replaced by solid bone.

There are many conditions that can lead to a hole or gap too big for bone cells to naturally fill in: birth defects, bone infections, and drastic surgeries for tumor removal are just some of them. Currently, our best technique for fixing such problems is a bone graft from a different part of the patient's body. But often such grafts won't take, and they aren't suited for the complex shapes needed to fix bone deformities in the face.

Dr. Grunlan's team's shape-memory polymer foam serves as a scaffold, spanning gaps in healthy bone and providing a structure for new bone cells to take hold and develop. The polymer is biodegradable, slowly dissolving as bone cells take over and disappearing when the healing process is complete.

The polymer already has a long track record of medical use, found in sutures and other biomedical materials. When heated to 140 degrees F, it's completely formable, allowing doctors to recreate the shape needed for both structural and cosmetic reconstruction. Wired explains how Grunlan's foam works:

In lab experiments, she and her colleagues coated [the foam] with another biodegradable polymer, called polydopamine, that is known to stimulate bone growth. They seeded the polymers with human bone cells, and after a few days saw that the cells were not only multiplying, but producing important bone-forming proteins.

Dr. Grunlan says that in humans, the foam could encourage complete bone regrowth in roughly a year. FDA approval is still likely five to 10 years away, but if it happens, it could be a huge boost for reconstructive surgery. [Grunlan Research Lab via Wired]

Image: Grunlan Research Lab