Porcupines sport some 30,000 quills, which easily penetrate flesh—and then stay stuck in it. Now, scientists have analyzed the shape of individual quills to discover what makes them so effective—and how we can harness their power for medical devices. The study is in the Proceedings of the National Academy of Sciences. [Woo Kyung Cho et al., Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal] The black tip of each quill features backward-facing barbs. These barbs are tiny: a row of two hundred of them would be short of an inch long. The barbs help a quill penetrate flesh more easily than a hypodermic needle of about the same diameter, and using only half the force required to push a barb-free quill through tissue. Once the quill is in, the barbs then greatly increase what force would be needed to pull it back out again. The researchers think understanding porcupine quill properties can help them make less painful needles, because of the lower force needed for penetration. Also stickier adhesives, because of the greater force needed for removal. And the study reminds us that you really, really don't want to mess with a porcupine. —Sophie Bushwick [The above text is a transcript of this podcast.] Follow Scientific American on Twitter @SciAm and @SciamBlogs. Visit ScientificAmerican.com for the latest in science, health and technology news.
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