BOSTON, MAResearchers from Brigham and Women's Hospital (BWH) have uncovered how North American porcupine quills easily penetrate tissues and why, once lodged in flesh, they are often difficult to remove.
The researchers, led by Jeffrey Karp, PhD, BWH Division of Biomedical Engineering, Department of Medicine, senior study author, along with Robert Langer, Ph.D from Massachusetts Institute of Technology (MIT), state that the discovery could prompt device makers to design medical needles that easily penetrate surfaces and resist buckling, as well as create next-generation medical adhesives.
The study will be published online on December 10, 2012 in Proceedings of the National Academy of Sciences.
The scientists used natural porcupine quills and replica-molded synthetic polyurethane quills to understand the physical forces at play when the quills penetrate and are removed from a variety of tissues, including muscle and skin.
The North American porcupine has approximately 30,000 defensive quills on its back. The porcupine releases its quills upon contact with predators. Each quill contains a conical black tip studded with a layer of microscopic, backward-facing barbs and a cylindrical base with smooth, scale-like structures.
The researchers revealed that the quill's geometry enables it to penetrate tissue with ease, and once in the tissue it maintains high adhesion.
"The philosopher Aristotle who was clearly misinformed warned that porcupines could shoot their quills over great distances, which is completely untrue," said Karp. "In fact there are many misconceptions about porcupines and their quills. We were most surprised to find that the barbs on quills serve a dual function. Namely, the barbs reduce the penetration force for easy insertion into tissue and maximize the holding force to make the quills incredibly difficult to remove."
According to the researchers, since quills do not shoo
|Contact: Marjorie Montemayor-Quellenberg|
Brigham and Women's Hospital