White Blood Cells Roll and Stick

Biological Strategy

Mammals

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Move in/on Liquids

Water is not only the most abundant liquid on earth, but it’s vital to life–so it’s no surprise that the majority of life has evolved to thrive on and under its surface. Moving efficiently in and on this dense and dynamic substance presents unique challenges and opportunities for living systems. As a result, they have evolved countless solutions to optimize drag, utilize surface tension, fine tune buoyancy, and take advantage of various types of currents and fluid dynamics. For example, sharks can slide through water by reducing drag due to their streamlined shape and specially shaped features on their skin.

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Attach Temporarily

Living systems must sometimes, temporarily, stay in one place, climb or otherwise move around, or hold things together. This entails attaching temporarily with the ability to release, which minimizes energy and material use. Some living systems repeatedly attach, detach, and reattach for an extended time, such as over their lifetimes. Despite being temporary, these attachments must withstand physical and other forces until they have achieved their purpose. Therefore, living systems have adapted attachment mechanisms optimized for the amount of time or number of times they must be used. An example is the gecko, which climbs walls by attaching its toes for less than a second. Other examples include insects that attach their eggs to a leaf until they hatch, and insects whose wings temporarily attach during flight but separate after landing.

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Mammals

Class Mammalia (“breast”): Bats, cats, whales, horses, humans

Mammals make up less than 1% of all animals on earth, but they include some of the most well-known species. We know first-hand some of the characteristics that make mammals unique, like having hair, being able to sweat, and producing milk through mammary glands. Another critical shared feature is a set of highly-specialized teeth. Unlike sharks or alligators, for example, whose teeth are generally all the same size and shape, mammals have differently shaped teeth in different areas of the jaws to target specific foods or foraging strategies.

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White blood cells of mammals roll along blood vessel walls, and anchor when they find an infection or cell damage via cell-adhesion molecules (CAMs) with variable affinity.

“Dan Hammer of the Univ. of Pennsylvania in Philadelphia is studying how white blood cells roll their way through the bloodstream, yet are able to anchor themselves where they are needed. He hopes that if he can devise materials that mimic the cells’ roll-and-stick ability, he’ll be able to devise a new targeted drug-delivery system. White blood cells have surface proteins called selectins that stick out of the cell surface. Fluid pushes the cell along–bonds form in front and are broken in the back, resulting in the cartwheeling motion.” (Courtesy of the Biomimicry Guild)

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Last Updated August 18, 2016

References

Journal article

Biology reveals new ways to hold on tight

Pennisi, E

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