If you or your dog has ever been on the wrong side of a porcupine, you know that their quills pack quite a punch. The average North American porcupine carries about 30,000 sharp quills on its back, which it uses to defend itself from predators that get too close. Those quills pierce flesh easily and then stay there, thanks to dozens of microscopic barbs at their tips.


Those two quill qualities — ease of insertion and difficulty of removal — could inspire new advances in medical needles and adhesives, according to research published December 10 in the Proceedings of the National Academy of Sciences.


The research was conducted by scientists from Brigham and Women's Hospital, the Harvard Stem Cell Institute and the Massachusetts Institute of Technology who in October also published research on new medical bandages inspired by spider webs and gecko feet. "We believe that evolution is the best problem-solver," co-author Jeffrey Karp, an associate professor of medicine at Harvard Medical School and co-director of the Center for Regenerative Therapeutics at Brigham and Women's Hospital, said in a prepared statement.


The key in both of these important stabbing and staying qualities is the barbs, the researchers found. The microscopic barbs act kind like a serrated knife when the quill goes into flesh, reducing the amount of energy required to break through the surface by up to 70 percent. Microneedles inspired by this natural structure could be allow doctors and surgeons to be more precise when making injections, since the flesh would have less "give" as the needle goes in. (This would also create less pain for the patients receiving the injections.)


The barbs would, in some cases, also be useful in keeping the needle in — for example, if they were part of a medical mesh to repair tears. Karp told Ed Yong at Discover that his team is working on quills with degradable barbs so the needles could be inserted for a set period of time and then more easily removed.


The barbs' great staying power also has benefit in adhesives. The researchers created an experimental adhesive patch using barbed quills and found that it required 30 times more energy to remove than a patch without barbs. A medical adhesive using these properties would be an improvement over the currently used sutures and staples, which can come apart too easily, causing leaks and other complications for patients.


As Karp explained to Medical News Today, the quill-inspired adhesive would be even better than the previous discovery inspired by gecko feet.  Those gecko-inspired bandages "require a reactive glue to adhere to wet tissues," Karp said, "while porcupine-quill-inspired adhesives attach to tissues beautifully without requiring the use of reactive chemistry."


Obviously any applications of this research are still years away, but the team says the potential medical uses are infinite. As Anthony Atala, a biomedical researcher from Wake Forest Baptist Medical Center (who was not affiliated with the study), told Science, "Now that we know how these barbs work, we can modify them to make devices perform even better."

Porcupine quills inspire new medical needles and adhesives
Needles need to go in easily, but medical adhesives need to hold. Porcupine quills do both.