Titanium foam builds Wolverine bones.

From New Scientist:

Eat your heart out, Wolverine. The X-Men superhero won't be the only one with metal fused into his skeleton if a new titanium foam proves suitable for replacing and strengthening damaged bones.

Bone implants are typically made of solid metal – usually titanium. Though well tolerated by the body, such implants are significantly stiffer than bone.

This means that an implant may end up carrying a far higher load than the bone it is placed next to, according to Peter Quadbeck of the Fraunhofer Institute for Manufacturing Technology and Advanced Materials Research in Dresden, Germany. In a worst-case scenario, the decrease in stress placed on the bone means it will deteriorate, while the implant loosens and needs to be replaced.

Now Quadbeck and colleagues have created a titanium implant with a foam-like structure, inspired by the spongy nature of bone. The titanium foam does a better job than solid metal when it comes to matching the mechanical properties of bone, such as flexibility, and this encourages more effective bone regrowth.

What's more, the foam is porous, so the bone can grow around and within it, truly integrating the implant with the skeleton.

The titanium foam is made by saturating polyurethane foam with a solution of titanium powder and binding agents. The titanium clings to the polyurethane matrix, which is then vaporised away along with the binding agents. This results in a titanium lattice which is finally heat-treated to harden it.