Unlocking the secret strength of marine mussels

(Press-News.org) How do you create strong, yet quick-release connections between living and non-living tissues? This is a question that continues to puzzle bioengineers who aim to create materials that bond together for advanced biomedical applications.

Looking to nature for inspiration, the McGill-led research zeroed in on the marine mussel byssus, a fibrous holdfast, which these bivalve mollusks use to anchor themselves in seashore habitats. The byssus attaches to rocky surfaces using an underwater glue, but the other end (the byssus stem root) is firmly anchored within the mussel’s soft living tissue. This area of contact between the living tissue and the non-living byssus stem root is known as a biointerface, and is the focus of a study by McGill professor of Chemistry Matthew Harrington.

“Up to this point, it was baffling how the byssus stem root biointerface could be strong enough to resist constant crashing waves but also be suddenly released by the mussel upon demand,” said Harrington. “It seemed as if the mussel could somehow control its strength.”

Surprisingly strong, yet releasable Following a cross-disciplinary investigation, the team found that the stem root separates into approximately 40-50 sheets known as lamellae that interlock with the living tissue, creating an incredibly strong interface much like interleaving two phone books together.

“The biggest surprise is how this strength can be lowered through the beating movements of billions of tiny hair-like cilia on the surface of the living tissue. Cilia movement is under the control of the neurotransmitters serotonin and dopamine, enabling the quick release of the whole stem root on demand.” says Harrington who holds the Canada Research Chair in Green Chemistry

Here's how a mussel's "beard" helps it hang tight and let loose

This finding is particularly relevant for biomedical engineers and materials scientists as they look towards the future of bio-implants, wearable sensors, brain-computer interface design, and more.

“The stem root biointerface is unlike anything seen in human-made materials and could offer important inspiration for the next generation of biointerfaces,” said Harrington. “Since further medical advances will depend on novel biointerface design, these findings could have impact on human health in the future.”

About the study A strong quick-release biointerface in mussels mediated by serotonergic cilia-based adhesion by Matthew Harrington et al., was published in Science. 

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