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 thenact as a working scaffold for replacement bone cells.  At least here they are able to replace missingmaterial with something that may be bone like.

The difficulty I see is that bone is actually dynamic inasmuch as it isconstantly responding to stress by growing reinforcing bone structures.  So while replacement may help offset damageit does not necessarily replace the natural integrity of bone.

I am sure that this will find application though, simply because we are along ways from doing all that we need.

Injecting New Bone

An artificial bone-like material could speedup recovery from injury.

Bone fixer: A liquid that solidifies into a bone-like material is injectedinto a model bone defect through a syringe. Credit: Thomas Webster

Today, a broken hip usuallymeans surgery and extensive rehab. But what if all you needed was an injectionand a shorter recovery period? That's the vision that inspires Thomas Webster, anassociate professor of engineering at Brown University.

Webster has developed ananomaterial that quickly solidifies at body temperature into a bone-likesubstance. This week, Brown announced a deal with medical device maker AudaxMedical of Littleton, Massachusetts, to further developthe material and launch trials in animals.

Thematerial contains the same nucleic acids as DNA, Webster says. Each moleculehas two covalent bonds and links with other molecules to form a tube. Henceit's called a "twin-base linker." (Audax will develop it under thename Arxis.)

"Itself-assembles into a nano structure, emulates natural tissue, solidifiesquickly at body temperature, and can be made to match the mechanical propertiesof the tissue you inject it into," Webster says.

Thatsounds great, says tissue engineer Kevin Shakesheff, of theUniversity of Nottinghamin the United Kingdom,but it will also need to sustain weight like bone can.

He andhis 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 tryand snap it, it's nowhere near as strong," he says.

Webstersays he's confident that his material, which has so far only been tested in alaboratory, will be able to bear weight like bone.

"Itwill have that strength after solidifying in the body—after a couple ofminutes," he says.

AliKhademhosseini, an assistant professor of medicine at Brigham andWomen's Hospital and Harvard Medical Schoolin Boston saysWebster's material sounds interesting, and there's plenty of room forinnovation 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, andparticularly in younger patients, it may eventually have to be replaced.Khademhosseini says tissue engineers are looking for materials that will betterintegrate with the body and last longer. If Webster succeeds in developing sucha material to replace metal entirely, that would transform the field, he says.
Audax will begin testingArxis in the hip and knee, according to company president and CEO Mark Johanson. Johanson hopes to have thefirst product ready for market in 2013. The company recently raised $1 millionand plans to raise more capital soon, Johanson says. If Arxis is injectable onan outpatient basis, the sales volume will be high and the price relativelylow, Johanson predicts. An injection is likely to run $1,000 to $1,500.

"Thematerial can be processed and manufactured relatively inexpensively, whichpositions it well for the higher-volume-procedural market," Johanson says.

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