Porcupine quills could hold key to improved hypodermic needles for medicine

Saturday, December 29, 2012 by: Jonathan Benson, staff writer
Tags: porcupine quills, hypodermic needles, medicine

(NaturalNews) If you have ever had a dog or other pet get snagged by them, then you already know how difficult it can be to remove porcupine quills from skin and tissue. But a new study published in the journal Proceedings of the National Academy of Sciences says the mechanism by which porcupine quills so easily penetrate the skin and stay there almost like an adhesive could play an important role in the advancement of medicine.

Researchers from Harvard Medical School (HMS) in Boston and the Massachusetts Institute of Technology (MIT) in Cambridge set out to study how the quills of porcupines, and specifically those of the North American porcupine, work so well at protecting porcupines against their predators. Upon investigation, the team, led by Woo Kyung Cho from HMS, learned that special microscopic barbs on the animals' quills appear to be the key to their penetrative effectiveness.

As it turns out, the quills found on the backs of North American porcupines -- these quills can number in the tens of thousands -- bear unique microscopic barbs that are conically arranged around the quills' tips. These barbs, which under a microscope somewhat resemble the seeds surrounding a pine cone, are pointed backwards, which means they can very easily slice through skin and tissue by applying many small, directed points of pressure on a surface area, similar to how a serrated knife cuts through bread.

Once lodged inside, these barbs cling to tissue, which makes pulling them out rather difficult. This is the reason, of course, why the porcupine is able to effectively defend itself against attackers. But what fascinated researchers the most about this discovery was how easily these tiny barbs, which cannot be seen by the naked eye, were able to effectively enter test skin without much force, which could have huge implications for future medical treatments, they say.

"The tests revealed that the barbed quills need only half as much force to penetrate pig skin as quills that have had the barbs removed -- but it takes four times as much force to pull them out," writes Ed Yong from Nature about the discovery. "On entry, the barbs localize forces at small points, like the serrated edges of a knife. But if the quill is pulled backwards, the barbs flare out and snag on tissue fibers."

Borrowing from nature to improve medical technologies

Simulating the natural design of the quills, researchers are already working on improved hypodermic needles that more easily penetrate the skin while causing less pain. The barb concept is also being incorporated into medical staples and other adhesives commonly used in medicine to repair injuries, which could become stronger and much more effective using porcupine technology.

"Towards medical applications, we developed plastic replicas that remarkably mimicked the reduced penetration forces and increased pullout," explained Dr. Jeffrey Karp one of the study's co-authors from Brigham and Women's Hospital in Boston. "This should be useful to develop next generation medical adhesives and potentially design needles with reduced pain."

Sources for this article include:

http://www.dailymail.co.uk

http://www.nature.com

http://www.npr.org