Friday Squid Blogging: Squid Beaks for Artificial Limbs?

Scientists are considering it:

The beak, made of hard chitin and other materials, changes density gradually from the hard tip to a softer, more flexible base where it attaches to the muscle around the squid’s mouth, the researchers found.

That means the tough beak can chomp away at fish for dinner, but the hard material doesn’t press or rub directly against the squid’s softer tissues.

Herbert Waite, a professor in the university’s department of molecular, cellular & developmental biology and co-author of the paper, said such graduated materials could have broad applications in biomedical materials.

“Lots of useful information could some out of this for implant materials, for example. Interfaces between soft and hard materials occur everywhere,” he said in a telephone interview.

Frank Zok, professor and associate chair of the department of materials, said he had always been skeptical of whether there is any real advantage to materials that change their properties gradually from one part to another, “but the squid beak turned me into a believer.”

“If we could reproduce the property gradients that we find in squid beak, it would open new possibilities for joining materials,” Zok said in a statement. “For example, if you graded an adhesive to make its properties match one material on one side and the other material on the other side, you could potentially form a much more robust bond.”

The researchers are learning lessons that can be applied to medical materials in the future, said Phillip B. Messersmith of the department of biomedical engineering at Northwestern University.

Messersmith, who was not part of the research team, noted that hard medical implants made of metal or ceramic are often imbedded in soft tissues.

“The lessons here from nature might be useful in transitions between devices and the tissues they are imbedded in,” he said in a telephone interview.

More on squid beaks.

Posted on April 4, 2008 at 4:38 PM4 Comments


alan April 4, 2008 6:07 PM

Great. Another prosthetics researcher has been reading the Necronomicon again. Next they will try grafting tentacles where the hands used to be.

“He’s a deep one…”

markm April 5, 2008 3:26 PM

Graduated material properties could be useful for things as prosaic as tool handles (soft grip, rigid and strong underneath) and wire strain reliefs.

thiefhunter April 5, 2008 7:02 PM

There’s a good example of graduated materials used to simulate a nursing breast at

“A process called overmolding allowed Whipsaw to combine two materials with different properties since a bottle always has two users: baby and parent. ‘The design innovation is in the integration of soft and rigid plastic properties into one uniform part that offers a soft end for baby and a bottle that’s easy to hold and fill for the parent,’”

David Alexander April 7, 2008 5:34 AM

This is nothing new. Swordsmiths have been making swords this way in Europe since something like 1000 AD.

They have very hard but somewhat brittle cutting edges and a softer, more flexible core, to absorb the impact of hitting the target.

It’s a combination of different alloys of steel and tempering the result at different rates by cooling at different rates.

Just google for making a katana/samurai sword, it’s usually well described there.

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