Researchers say they may soon be able to repair injured and worn-out cartilage with the help of nanotubes. Currently, patients must either go under the knife to mend faulty cartilage (connective tissue that normally pads the ends of bones at joints to keep them from grinding against one another). But scientists say they may one day be able to insert microscopic carbon nanotubes into injured joints—such as knees—encouraging new, stronger cartilage cells to grow in place damaged or thinning ones.

Researchers report in the Journal of Biomedical Materials Research Part A that they successfully grew cartilage around carbon nanotubes in their lab—and are optimistic that one day they will be able to duplicate the feat inside the human body. They may get a step closer in September, when they plan to implant carbon nanotubes in sheep joints to test—for the first time—their technique outside the lab.

Thomas Webster, an associate engineering professor at Brown University, and Brown researcher Dongwoo Khang, along with Grace Park, a research scientist (and one of Webster's former PhD students) at Becton, Dickinson and Company, a Franklin Lakes, N.J.–medical technology firm, say they grew cartilage cells by placing chondrocytes (cartilage-forming cells) and carbon nanotubes together on a polycarbonate urethane surface. As expected, cartilage cells grew around the nanotubes, which are so strong that scientists now use them to reinforce plastic. Researchers say they hastened new cell production by sending electrical surges through the nanotubes, which are also excellent conductors of electricity.

Scientists envision implanting nanotubes through small incisions (in, say, a knee) that a patient's own cartilage cells would colonize. The benefit, Webster says, is that the cartilage would grow more quickly and be stronger than if it was not supported by nanotubes—similar to the way that steel rebar is used to reinforce cement or concrete. He notes that nanotubes would adhere well to existing cartilage. "The patient will have a faster return [than if they used cartilage without nanotubes] to an active lifestyle that they probably have not had in a long time," he says.

Orthopedic surgeons commend Webster's research but say it is too early to tell whether his approach will be successful. Although the idea of creating stronger, better-adhering cartilage sounds good, placing permanent particles such as carbon nanotubes inside the joint may introduce other problems, says Freddie Fu, chairman of the Department of Orthopaedic Surgery at the University of Pittsburgh's School of Medicine and its Medical Center. His major concern: that carbon nanotubes may not be biologically compatible with existing cartilage tissue in the joint.

"Ideally, the architecture of the scaffold should mimic that of the native tissue to be repaired," says Wei Shen, a postdoctoral research associate also in the department.

Scientists for decades have been seeking ways to repair cartilage without resorting to traditional surgery, which typically involves removing damaged cartilage through an incision in the joint while trying to preserve as much of the healthy tissue as possible. One breakthrough was the development in 2002 of gels made of synthetic materials such as polyhydroxyethyl methacrylate, which can be injected into a joint where it solidifies and becomes a cushion with the same shock-absorbing function as cartilage. The problem is, Webster says, the gel pads do not always adhere well to the remaining cartilage in the joint, which means that many patients require follow-up injections. Another concern, Fu says, is that even if the gel sticks it may not last long.

Researchers at the Massachusetts Institute of Technology, Harvard Medical School and the University of Colorado at Boulder are currently trying to develop a gel into which they could place a patient's own cartilage cells that would reproduce once the solution was injected into a target joint. This approach, however, does not use carbon nanotubes, which Webster believes would provide a more durable fix.

Webster has been studying the possibility of growing tissue around nanomaterials since 1998 when he was a graduate student at Rensselaer Polytechnic Institute in Troy, N.Y. "Nanoscale materials are increasing growth in all of these tissue types," he says. "The key is getting the nanomaterials to mimic the roughness of the natural tissue, which creates more surface energy and allows for the absorption of proteins important for the tissue to function."

Webster has come a long way since his original experiments with in vitro bone tissue growth. Over the past decade, he added bladder, cartilage, central nervous system, and vascular tissue growth to his repertoire. The principle is the same in each: Growing cells are more likely to adhere to and thrive on a rough nanotube surface than on smooth bone or fraying cartilage. He is now working with a team of 26 biomedical and tissue engineering researchers at Brown, armed with a $500,000 grant from the National Science and Technology Council's federal National Nanotechnology Initiative, to see how far he can push his ideas.

"The use of nanotechnology in scaffolds to assist with regenerating cartilage is novel," says Constance Chu, director of the University of Pittsburgh Medical Center's Cartilage Restoration Program and an orthopedic surgeon specializing in cartilage regeneration and osteoarthritis, "and would be of high interest if it can eventually improve the functional properties of the regenerated cartilage."

4 Comments

1. 1. Anastasia 08:15 AM 8/9/08

   By Anastasia Matyatina
   
   Science is built up of facts,
   as a house is built of stones;
   but accumulation of facts is no more a science
   than a heap of stones is a house.
   Jules-Henry Poincar�
   
   This article interested me from the very beginning. No, it is not right, from its title. Even the first word, nanotech, made me to remind that lots of American, European, Russian universities, schools and academies count on this branch of knowledge; scientists get grants from the government on their research work in this field.
   
   Nowadays, nanotechnologies have found their place even in every branch of manufacture, for example, in medicine. Moreover, I consider it being the most important side, as behind this word medicine stand lots of patients, who, may be in this moment, wait for the operation or even dream, that such operations and procedures one day will become less expensive. So for such people this article is a drop of hope, hope on the happy end or more successful result of their treatment.
   
   In addition to this, there is one more important issue for nanotech in medicine. Imagine that the patient has money for the operation, but there is one more factor: the age of the patient. Of course, if our hero is a young man, everything will be ok. But if he is an old person, the consequences of this operation may be irreversible. During reading, Ive found the solution in the following words: Currently, patients must either go under the knife to mend faulty cartilage. But scientists say they may one day be able to insert microscopic carbon nanotubes into injured joints  such as knees  encouraging new, stronger cartilage cells to grow in place damaged or thinning ones. It means that such operations will require only several incisions and, in most cases, only local, not general, anesthetic. This is the way out of a situation for people with cardio-vascular diseases and other health problems.
   
   Now, it is time to go into details, as far as I know this problem and, of course, as far as this article allows me.
   
   I was really amazed at the words of Brown Universitys professor, Thomas Webster, who said: &the cartilage would grow more quickly and be stronger than if it was not supported by nanotubes  similar to the way that steel rebar is used to reinforce cement or concrete. It is none other than the patient will have a faster return [than if they used cartilage without nanotubes] to an active lifestyle that they probably have not had in a long time. I think it is great! When the patient is not active, for example he lies all day long and cant stand or his leg is in plaster, all groups of his muscles atrophy and it is extremely difficult to return their to that condition, as it was before. There are many people who cant overcome this trouble, as there are lots of methods, but they dont know which of them is suitable exactly for themselves. Moreover, there are only several specialized highly qualified rehabilitation centers in the world while lots of people need theirs help. As you can see, nanotech offers its own original solution to every problem.
   
   But, of course, there is just one snag. It is in the words of Freddie Fu, chairman of the Department of Orthopedic Surgery at the University of Pittsburghs School of Medicine: Although the idea of creating stronger, better-adhering cartilage sounds good, placing permanent particles such as carbon nanotubes inside the joint may introduce other problems. His major concern,  as it is said in the article,  that carbon nanotubes may not be biologically compatible with existing cartilage tissue in the joint.
   
   No doubt that it is a fly in the ointment. But we deal with peoples health, so we must look at inaccuracies, eliminate all errors and defects.
   
   Nevertheless, I want to remind the words of the great American scientist, philosopher, publisher and statesman of the 18th century, Benjamin Franklin: A little carelessness may cause great trouble. And it is right! It is better to find faults now, than to have irreparable consequences in the future.
   
   So in conclusion, Id like to mention the following.
   Once Francis Bacon said: If we begin with certainties,
   We shall end in doubts,
   But if we begin with doubts,
   And are patient in them,
   We shall end in certainties.
   Id like to wish Thomas Webster to begin only with doubts and every success in his uneasy, important work. Moreover, Id like to thank Larry Greenemeier for this article and excellent selection of information and ask him for one more article on this topic or more details about scientists work in this field.
   

   Reply | Report Abuse | Link to this

2. 2. uberclimber 09:51 PM 1/5/09

   How about hips? Will the same technique work to repair damaged hip cartilage, I wonder (I hope)?

   Reply | Report Abuse | Link to this

3. 3. rockjohny 03:32 PM 8/6/09

   In Europe, they will inject joints with HLA or hyaluronic acid but here in USA, it's only approved for veteranary use but it is one of the few treatments that i've heard gives real relief.
   
   From Wiki: hyaluronan is a major component of the synovial fluid and was found to increase the viscosity of the fluid. Along with lubricin, it is one of the fluid's main lubricating components.
   
   Hyaluronan is an important component of articular cartilage, where it is present as a coat around each cell (chondrocyte).

   Reply | Report Abuse | Link to this

4. 4. MARKO 11:44 AM 4/4/10

   IF YOU USE PROLOTHERAPY YOUR CARTIALGE WILL GROW BACK AND ALSO HEAL TENDONS AND LIGAMENTS. USING CARTIAGLE #2 AND CARTIALGE1&3 WITH HYALUNIC ACID, AND OTHER CARTILAGE GROWING NUTRIENTS WILL HELP.

   Reply | Report Abuse | Link to this