Bone-growing nanomaterial could improve orthopaedic implants

September 17, 2007

PROVIDENCE, R.I. [Brown University] -- For orthopaedic implants to be successful, bone must meld to the metal that these artificial hips, knees and shoulders are made of. A team of Brown University engineers, led by Thomas Webster, has discovered a new material that could significantly increase this success rate.

The team took titanium - the most popular implant material around - and chemically treated it and applied an electrical current to it. This process, called anodization, creates a pitted coating in the surface of the titanium. Webster and his team packed those pits with a cobalt catalyst and then ran the samples through a chemical process that involved heating them to a scorching 700° C. That caused carbon nanotubes to sprout from each pit.

Researchers then placed human osteoblasts, or bone-forming cells, onto the nanotube-covered samples as well as onto samples of plain and anodized titanium. The samples were placed in an incubator. After three weeks, the team found that the bone cells grew twice as fast on the titanium covered in nanotubes. Cells interacting with the nanotubes also made significantly more calcium - the essential ingredient for healthy bones.

Results are published in Nanotechnology.

"What we found is possibly a terrific new material for joint replacement and other implants," said Webster, associate professor of engineering at Brown. "Right now, bone doesn't always properly meld to implants. Osteoblasts don't grow or grow fast enough. Adding carbon nanotubes to anodized titanium appears to encourage that cell growth and function."

Webster's long-term vision for the new material is ambitious. With it, Webster hopes to create a new class of implants - ones that can sense bone growth then send that information to an external device. Doctors could monitor the output and determine whether to inject growth hormones or otherwise intervene to avoid additional surgery. Right now, implant patients must get an X-ray or undergo a bone scan to monitor bone growth.

Webster thinks these "biosensing" implants could even be designed to detect infection and be specially coated to release antibiotics or other drugs into the body.

Webster said the biosensing concept would work because when cells make calcium, an electrical current is created. That current can be conducted through carbon nanotubes and transmitted via radio frequency to a handheld device outside the body - a similar process to the one employed by state-of-the-art cardiac pacemakers.

"This technology would be incredibly exciting," Webster said. "It could significantly improve patient health - and cut down on expensive diagnostic tests and surgery. We still have a long way to go to make an intelligent implant a reality, but our new results are a strong first step."
-end-
Webster's Brown research team included engineering graduate student Sirinrath Sirivisoot, the lead author of the Nanotechnology article, engineering graduate students Chang Yao and Xingcheng Xiao and professor of engineering Brian Sheldon.

The Coulter Foundation funded the research.

Editors: Brown University has a fiber link television studio available for domestic and international live and taped interviews and maintains an ISDN line for radio interviews. For more information, call the Office of Media Relations at (401) 863-2476.

Brown University

Related Carbon Nanotubes Articles from Brightsurf:

How plantains and carbon nanotubes can improve cars
Researchers from the University of Johannesburg have shown that plantain, a starchy type of banana, is a promising renewable source for an emerging type of lighter, rust-free composite materials for the automotive industry.

New production method for carbon nanotubes gets green light
A new method of producing carbon nanotubes -- tiny molecules with incredible physical properties used in touchscreen displays, 5G networks and flexible electronics -- has been given the green light by researchers, meaning work in this crucial field can continue.

Growing carbon nanotubes with the right twist
Researchers synthetize nanotubes with a specific structure expanding previous theories on carbon nanotube growth.

Research shows old newspapers can be used to grow carbon nanotubes
New research has found that old newspaper provide a cheap and green solution for the bulk production of single walled carbon nanotubes.

Clean carbon nanotubes with superb properties
Scientists at Aalto University, Finland, and Nagoya University, Japan, have found a new way to make ultra-clean carbon nanotube transistors with superior semiconducting properties.

Dietary fiber effectively purifies carbon nanotubes
A dietary fiber can help separate out semiconducting carbon nanotubes used for making transistors for flexible electronics.

Why modified carbon nanotubes can help the reproducibility problem
Scientists at Tokyo Institute of Technology (Tokyo Tech) conducted an in-depth study on how carbon nanotubes with oxygen-containing groups can be used to greatly enhance the performance of perovskite solar cells.

Tensile strength of carbon nanotubes depends on their chiral structures
Single-walled carbon nanotubes should theoretically be extremely strong, but it remains unclear why their experimental tensile strengths are lower and vary among nanotubes.

New study reveals carbon nanotubes measurement possible for the first time
Swansea University scientists report an entirely new approach to manipulation of carbon nanotubes that allows physical measurements to be made on carbon nanotubes that have previously only been possible by theoretical computation.

Neural networks will help manufacture carbon nanotubes
A team of scientists from Skoltech's Laboratory of Nanomaterials proposed a neural-network-based method for monitoring the growth of carbon nanotubes, preparing the ground for a new generation of sophisticated electronic devices.

Read More: Carbon Nanotubes News and Carbon Nanotubes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.