Scientists have shown for the first time that carbon nanotubes make an ideal scaffold for the growth of bone tissue. The new technique could change the way doctors treat broken bones, allowing them to simply inject a solution of nanotubes into a fracture to promote healing.
The report appears in the June 14 issue of the American Chemical Society's journal Chemistry of Materials.
The success of a bone graft depends on the ability of the scaffold to assist the natural healing process. Artificial bone scaffolds have been made from a wide variety of materials, such as polymers or peptide fibers, but they have a number of drawbacks, including low strength and the potential for rejection in the body.
"Compared with these scaffolds, the high mechanical strength, excellent flexibility and low density of carbon nanotubes make them ideal for the production of lightweight, high-strength materials such as bone," says Robert Haddon, Ph.D., a chemist at the University of California, Riverside, and lead author of the paper. Single-walled carbon nanotubes are a naturally occurring form of carbon, like graphite or diamond, where the atoms are arranged like a rolled-up tube of chicken wire. They are among the strongest known materials in the world.
Bone tissue is a natural composite of collagen fibers and hydroxyapatite crystals. Haddon and his coworkers have demonstrated for the first time that nanotubes can mimic the role of collagen as the scaffold for growth of hydroxyapatite in bone.
"This research is particularly notable in the sense that it points the way to a possible new direction for carbon nanotube applications, in the medical treatment of broken bones," says Leonard Interrante, Ph.D., editor of Chemistry of Materials and a professor in the department of chemistry and chemical biology at Rensselaer Polytechnic Institute in Troy, N.Y. "This type of research is an example of how chemistry is being used everyday, world-wide, to develop materials that will improve peoples' lives."
The researchers expect that nanotubes will improve the strength and flexibility of artificial bone materials, leading to a new type of bone graft for fractures that may also be important in the treatment of bone-thinning diseases such as osteoporosis.