RIVERSIDE, Calif. www.ucr.edu – Osteoporosis
sufferers and victims of broken bones may have the tiniest of friends in carbon
nanotubes, according to researchers at the University of California, Riverside.
The strength, flexibility and light weight of carbon nanotubes – structures 100,000
smaller than a human hair – allow them to act as scaffolds to hold up regenerating
bone, according to Distinguished
Professor of Chemistry Robert C. Haddon , the director of the Center for
Nanoscale Science and Engineering at UC Riverside.
“They're the perfect replacement: Small, strong, and they're carbon based,” said
Haddon, lead author of a paper titled A Bone Mimic Based on the Self-Assembly
of Hydroxyapatite on Chemically Functionalized Single-Walled Carbon Nanotubes, which
was published in June in the American Chemical Society's journal Chemistry
of Materials . Haddon's UCR co-authors included graduate students Bin Zhao
and Hui Hu, and postdoctoral researcher Swandhin K. Mandal.
The findings by Haddon and his colleagues may lead to improved flexibility and
strength of artificial bone, new types of bone grafts and to inroads in the treatment
of osteoporosis. Haddon expects it will attract interest from other researchers
and companies interested in developing new bone-graft materials and techniques.
“This research is particularly notable in the sense that it points the way to
a possible new direction for carbon nanotube application, in the medical treatment
of broken bones,” said Leonard Interrante, editor of Chemistry of Materials,
in an American Chemical Society statement. Interrante is also a professor 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, worldwide,
to develop materials that will improve people's lives.”
Artificial bone scaffolds have been made from a wide variety of materials, such
as polymers or peptide fibers. Their drawbacks include low strength and the potential
for rejection in the body.
“The single walled carbon nanotubes are extremely strong materials,” Haddon said. “And
since bone is a composite mixture of organic and inorganic material, the nanotubes
make an excellent replacement for the organic part.”
Single-walled carbon nanotubes are a 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 crystalline hydroxyapatite,
which is a mineral based on calcium phosphate. Haddon and his team have demonstrated
that carbon nanotubes can mimic the role of collagen as a scaffold for inducing
the growth of hydroxyapatite crystals.
The trick, Haddon said, was finding a way to cluster the growth of hydroxyapatite
crystals on the carbon nanotube scaffold. By chemically treating the nanotubes,
it was possible to attract calcium ions and this promoted the crystallization
process while improving the biocompatibility of the nanotubes by increasing their
Haddon's findings also show that nanotechnology can be used in a variety of ways
to help the body heal itself.
He and Assistant Professor of Neuroscience, Vladimir Parpura, together with other
UCR researchers are investigating the role of carbon nanotubes in the formation
of similar scaffolds to stimulate the growth of neurons.
of the Article
- The Center
for Nanoscale Science and Technology at UCR Additional
C. Haddon The University of California, Riverside
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and graduate enrollment of nearly 17,000, the
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