In the world of materials, stiffness and stretchiness are usually incompatible.

But mussels seem to have figured out how to be stiff and stretchy. Their byssal threads - the fibers that attach them to rocks and other surfaces - have a protective coating, or cuticle, that can stretch up to 70 percent without cracking.

Researchers at the University of California, Santa Barbara, have discovered that among other things, what enables the cuticles to stretch are deformable granules that stop tiny cracks from getting bigger. The research, reported by J. Herbert Waite and others in the journal Langmuir, looks at the chemistry of the cuticle. The researchers found that two metals, calcium and iron, were distributed throughout the cuticle.

The researchers also found that the metals were co-located with L-dopa, a key component of the cuticle proteins. The researchers say this suggests that the metals and L-dopa may form complexes that help keep the cuticle together under strain.

The findings may eventually help in the development of biomimetic coatings for medical implants or industrial devices.


HENRY FOUNTAIN