Mineralized Jaws Resist Abrasion

Biological Strategy

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Manage Mechanical Wear

A living system is subject to mechanical wear when two parts rub against each other or when the living system comes in contact with abrasive components in its environment, such as sand or coral. Some abrasive components are a constant force, such as finger joints moving, while others occur infrequently, such as a sand storm moving across a desert. Living systems protect from mechanical wear using strategies appropriate to the level and frequency of the source, such as having abrasion-resistant surfaces, replaceable parts, or lubricants. For example, human joints like shoulders and knees move against each other all day, every day. To protect from mechanical wear, a lubricant reduces friction between the cartilage and the joint.

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Animals

Kingdom Animalia (“having breath or soul”): Mammals, reptiles, sponges, corals, insects, birds

This kingdom captures a staggering variety of life—from the smallest coral polyp to the largest elephant. Although animal body shapes and life histories vary, there are a few defining characteristics. Animals are heterotrophs, meaning they gain energy from eating other organisms, and have developed from single-celled ancestors to highly diversified and coordinated multicellular forms. Unlike plant and fungi cells that have rigid cell walls, animal cells are bound by more flexible combinations of proteins. Most animals have cells organized into tissues and are able to move within their environment.

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Jaws of blood worms are hard and wear resistant due to stratified composites containing precise configurations of proteins and two forms of copper.

Nature uses chemistry to build strong, resilient, tough materials tailor made for the job at hand. The carnivorous bloodworm, for instance, needs a hard, wear-resistant, flexible jaw to knaw through carapaces and burrow through sediment. It’s recipe includes four substances: s, melanin , copper ions, and atacamite (a mineralized form of copper) arranged in four layers in precise patterns and thicknesses. Copper ions facilitate a tight network between proteins and pigment in the thin outermost layer as well as in the third layer confering hardness and wear resistance. Sandwiched between these two is a layer reinforced with atacamite fibers thought to confer flexibility to the entire jaw. The innermost layer contains ony trace amounts of copper.

Last Updated August 23, 2016

References

Journal article

High abrasion resistance with sparse mineralization: copper biomineral in worm jaws

Bloodworm's way with copper likely provides paradigm for new materials

Journal article

Diverse Strategies of Protein Sclerotization in Marine Invertebrates

Advances in Insect Physiology: Insect Integument and Colour | 23/06/2010 | Daniel J. Rubin, Ali Miserez, J. Herbert Waite

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