Thread made of crab shell and polyester can stitch together broken nerves


Researchers at the University of Washington have woven together chitosan and polyester to create a new material that can help to repair severed nerves. Chitosan, found in the shells of crabs and shrimp, was mixed with an industrial polyester; the hybrid fibre combines the biologically favourable qualities of the natural material with the mechanical strength of the synthetic polymer.

"A nerve guide requires very strict conditions. It needs to be biocompatible, stable in solution, resistant to collapse and also pliable, so that surgeons can suture it to the nerve," said lead author Miqin Zhang, a professor of material science and engineering, "This turns out to be very difficult."

When a peripheral nerve (such as one in a finger) is severed, nerve endings continue to grow. But to repair the nerve surgeons must join the two fragments together. In the past, surgeons used to bridge large gaps with a difficult nerve graft. Current surgical practice is to attach tiny tubes, called nerve guides, that channel the two fragments toward each other.

Left: a closeup of chitosan and polyester fibers woven at the nanometer scale. Centre: a nerve cell growing on the resulting mesh, which has a texture similar to the body's fibrous connective tissue. Right: a cross-section of the synthetic nerve guide. Arrows point to nerve cells that have attached to the inner and outer surfaces of the tube.

Today's commercial nerve guides are made from collagen, a structural protein derived from animal cells. But collagen is expensive, and the protein tends to trigger an immune response. By contrast, chitosan is cheap, biodegradable, and does not trigger an immune reaction. Combining that with polycaprolactone - a strong, water-repellent, biodegradable material already used in sutures, resulted in a material 8 times stronger than collagen.

Zhang envisions the new material finding uses in a broad range of biomedical applications, including heart grafts, tendons, ligament, cartilage, muscle repair and more. This new material doesn't appear to have a name though. Any suggestions?

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You're going to have to duke it out with Jennifer Jacquet at Guilty Planet. She trying to save sea life and here you are broadcasting about yet another impetus to exploit it!

@ Paul Browne
Sorry - should have added links. Research is published in Advanced Materials, more info here.

There's an obvious name for it: Crabstick.

Just as long as they don't start using Louis Kemp's Crab Delights. Not sure white fish will have the same effect.

By JimmyJojo (not verified) on 19 Jun 2009 #permalink

We already harvest tons of lobster, shrimp, crabs, etc. Most of these offerings come peeled. Just buy up the scrap shell and there you go. No further exploitation needed.

How does it not trigger an immune response? I'm allergic to shellfish. There's a joint medication "Chondroitin" which contains chitin, and I can't take that, otherwise I have an allergic reaction. Sorry for any spelling mistakes...



There is no exploitation involved. On the contrary, its about the RECYCLING of shells. Chitosan is proven extremely good in the purification of water as well.