Engineers at Missouri University of Science and Technology, Rolla, have developed a glass-based scaffold that could one day be used as an implant to repair injured bones in the arms, legs, and other weight-bearing areas of the body. This marks the first time researchers have shown a glass implant strong enough to bear weight can also integrate with bone and promote bone growth, they say. Previously, they had developed a glass implant strong enough to handle the weight and pressure of repetitive movement, like walking or lifting. The difference is that this implant consists of porous scaffolding, which can also integrate with bone and promote bone growth. This combination of strength and bone growth opens new possibilities for bone repair, they say.

Glass is bioactive, which means that it reacts when implanted in living tissue and converts to a bone-like material. This differs sharply from other conventional approaches to structural bone repair, which use either a porous metal, which does not reliably heal bone, or a bone allograft from a cadaver. Both of these approaches are costly and carry risks, the engineers say.

The scaffolds are manufactured in at the university in a process known as robocasting, which is a computer-controlled technique to manufacture materials from ceramic slurries, layer by layer to ensure uniform structure for the porous material. The porous scaffolds of the silicate glass, known as 13-93, were found to have the same strength properties as cortical bone, the outer bones of the body that bear the most weight and repetitive stress.

In their study, the researchers found that the bioactive glass scaffolds bonded quickly to bone and promoted a significant amount of new bone growth within six weeks.

In the future, they plan to modify the glass scaffolds to see how well they enhance certain attributes within bone. For example, doping the glass with copper should promote the growth of blood vessels or capillaries within the new bone, they say, while doping the glass with silver will give it antibacterial properties.