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.
Bone fixer: A liquid that solidifies into a bone-like material is injected into a model bone defect through a syringe.
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 Littleton, Massachusetts, to further develop the material and launch trials in animals.
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 United Kingdom, but it will also need to sustain weight like bone can.
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 in Boston says Webster's material sounds interesting, and there's plenty of room for innovation in the area of bone-like materials.
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.
By Karen Weintraub
From Technology Review