April 2002

Skeleton Recharge

Bringing artificial bones to life.

By Alexandra Stikeman

It's not quite Mary Shelley's image of a corpse brought to life by electricity, but biomedical engineers have found a way of using electricity to bring artificial bone to life. The method could one day yield bone replacement parts.

Bioengineer Rena Bizios at Rensselaer Polytechnic Institute uses carbon nanotubes-tubular molecules that are good electrical conductors-to deliver electricity to bone-forming rat cells deposited on a piece of polymer. Researchers have long known that electrical stimulation enhances bone growth, but it's hard to deliver the electricity uniformly: new bone tends to clump around the electrodes delivering the charge. Bizios's technique could solve that problem, though, since the nanotubes are embedded throughout the polymer. When the researchers turned on the electricity, the bone cells grew and began to deposit the proteins and calcium that give bone its strength. That the technique worked so well "was a great surprise," says Bizios.

Researchers don't know yet if the approach will ultimately yield uniform bone tissue, but the results are "very exciting and very promising," says Antonios Mikos, a biomedical engineer at Rice University. While doctors can treat small bone injuries by surgically implanting patchlike materials, they can't yet generate the large sections of bone that would be needed to replace a hip ravaged by osteoporosis, for example. Bizios's material, on the other hand, opens up the possibility of quickly growing large sections of artificial bone in the lab using a patient's own cells and nanotube-wired polymer scaffolding. Surgeons could then replace any damaged or diseased parts of a patient's skeleton with the new bone.