Monday, December 27, 2010
Injecting New Bone
This obviously has a long way to go. One would love to see a material able to first model the damage and then act as a working scaffold for replacement bone cells. At least here they are able to replace missing material with something that may be bone like.
The difficulty I see is that bone is actually dynamic inasmuch as it is constantly responding to stress by growing reinforcing bone structures. So while replacement may help offset damage it does not necessarily replace the natural integrity of bone.
I am sure that this will find application though, simply because we are a long ways from doing all that we need.
Injecting New Bone
An artificial bone-like material could speed up recovery from injury.
BY KAREN WEINTRAUB
A liquid that solidifies into a bone-like material is injected into a model bone defect through a syringe. Credit: Thomas Webster
Today, a broken hip usually means surgery and extensive rehab. But what if all you needed was an injection and a shorter recovery period? That's the vision that inspires Thomas Webster, an associate professor of engineering at
. Brown University
Webster has developed a nanomaterial that quickly solidifies at body temperature into a bone-like substance. This week, Brown announced a deal with medical device maker Audax Medical of
, to further develop
the material and launch trials in animals. Littleton,
The material contains the same nucleic acids as DNA, Webster says. Each molecule has two covalent bonds and links with other molecules to form a tube. Hence it's called a "twin-base linker." (Audax will develop it under the name Arxis.)
"It self-assembles into a nano structure, emulates natural tissue, solidifies quickly at body temperature, and can be made to match the mechanical properties of the tissue you inject it into," Webster says.
That sounds great, says tissue engineer Kevin Shakesheff, of the
University of Nottingham
in the ,
but it will also need to sustain weight like bone can. United Kingdom
He and his colleagues have developed a different material for the same purpose. "If you press down on our material, it's as strong as bone, but if you try and snap it, it's nowhere near as strong," he says.
Webster says he's confident that his material, which has so far only been tested in a laboratory, will be able to bear weight like bone.
"It will have that strength after solidifying in the body—after a couple of minutes," he says.
Ali Khademhosseini, an assistant professor of medicine at Brigham and Women's Hospital and
Harvard Medical School
Webster's material sounds interesting, and there's plenty of room for
innovation in the area of bone-like materials. Boston
Today, metal plates are often inserted to provide strength and support while bones, such as the hip joint, slowly heal. But the metal degrades over time, and particularly in younger patients, it may eventually have to be replaced. Khademhosseini says tissue engineers are looking for materials that will better integrate with the body and last longer. If Webster succeeds in developing such a material to replace metal entirely, that would transform the field, he says.
Audax will begin testing Arxis in the hip and knee, according to company president and CEO Mark Johanson. Johanson hopes to have the first product ready for market in 2013. The company recently raised $1 million and plans to raise more capital soon, Johanson says. If Arxis is injectable on an outpatient basis, the sales volume will be high and the price relatively low, Johanson predicts. An injection is likely to run $1,000 to $1,500.
"The material can be processed and manufactured relatively inexpensively, which positions it well for the higher-volume-procedural market," Johanson says.