Twenty first century medicine has often turned to the ocean for new discoveries. Now, the humble crab is in the spotlight. An extract from crab shells may have uses in surgery. Dr. Maryanne Demasi investigates.

TRANSCRIPT

Dr Maryanne Demasi: How delicious does this look? I can’t wait to crack open the shell and sink my teeth into the tasty crab meat.

But have you ever thought about how useful the shell could be? Well, scientists have realised that an extract from this could have uses in medicine.

Associate Professor John Foster: Crustacea such as crabs and insects have, contrary to us, what’s called an exoskeleton, so the the crab shell is not just an enclosing body, it actually acts as a support mechanism so the flesh inside the muscles, the tissue etc, actually binds to the inside of the skeleton itself.

Narration: This binding ability is helped by an extract called “Chitosan” which is now making its way into the operating theatre as a ‘surgical adhesive’.

One day, it may replace the age old technique of stitching tissue together with needle and thread.

Assoc. Professor Foster: Sutures are a five-thousand year old technology which have changed very little. They’re a source of infection, they cause scarring, and they don’t actually seal the wound, they just pull the two pieces of the wound edges close together.

Narration: There are adhesive gels and fibrin glues used in surgery at the moment, but they can be toxic or too weak to hold tissue together.

Assoc. Professor Foster: We wanted something that will be quick, cheap, effective, would avoid the different uses of surgical technical skill, and would not only close the wound but seal it as well.

Well as you can see this is the, chitosan film.

Maryanne: Ah, can I touch it?

Assoc. Professor Foster: Yes, certainly. It’s safe to touch.

Maryanne: Oh, it’s very thin too.

Assoc. Professor Foster: Yes, we can make it any thickness you like.

Maryanne: And it’s very flexible too, isn’t it?

Assoc. Professor Foster: Yes indeed, extremely flexible, so you can actually use it for keyhole surgery, it’s also anti-microbial, so it prevents wound infection.

Narration: In the lab, the film is fixed over two pieces of tissue and welded in place by a laser.

Maryanne: Now we’re about to see the chitosan film put into action.

Narration: Associate Professor Marcus Stoodley is a neurosurgeon and an expert at repairing damaged nerves.

Associate Professor Marcus Stoodley: What we’re exposing here is the sciatic nerve in the rat which is very similar to the sciatic nerve in human, which controls most of the muscles in the lower limb.

Narration: Marcus now begins the pain staking task of stitching the nerve together in the conventional way.

Assoc. Professor Stoodley: That’s 4 stitches, I’ll probably need to put in another 10 stitches.

Narration: Where as that took almost an hour, the chitosan film only takes a few minutes.

Maryanne: That’s just how it sticks the tissue in the crab shell

Assoc. Professor Stoodley: So I’ll just roll it around to complete the collar.

Narration: A laser is now used to weld the film to the surface of the nerve.

Assoc. Professor Stoodley: The chitosan really is very strong and adheres to biological tissue better than anything else that I’ve ever used. We certainly have tried many things to stick material together or tissues together in neurosurgery and nothing is as strong as the chitosan or sticks as well as the chitosan does.

Maryanne: So you’d be ready to stitch it up now?

Narration: We can now sew up the muscle and skin and its all done.

Assoc. Professor Foster: We’re not actually using this chitosan film in humans at the present moment in time, we’re still at the testing stage using animals, and we hope to see it being used um within five years.

Story Contacts

Associate Professor John Foster  

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Associate Professor Marcus Stoodley  

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