Once a porcupine’s quill penetrates your skin, it’s very difficult to remove. That’s the inspiration behind research at Massachusetts Institute of Technology and Brigham and Women’s Hospital, Boston, to develop new types of adhesives, needles, and other medical devices.

In a new study, researchers characterized the forces needed for quills to enter and exit the skin. They also created artificial devices with the same mechanical features as quills, raising the possibility of designing less-painful needles, or adhesives that can bind internal tissues more securely.

Porcupines have about 30,000 barbed quills, each several centimeters long, and the four millimeters at the very tip are covered in microscopic barbs. To their surprise, the researchers found that despite the difficulty of removing the quills, they require very little force to penetrate tissue. The team then set out to determine how the quills achieve this unique combination and discovered that the barbs are the key to both.

To explore the possibility of making stronger adhesives, the researchers created a patch with an array of barbed quills on one side. They found that the energy required to remove this patch was 30 times greater than that needed for a control patch, which had quills but no barbs.

The system could also be tweaked so that it penetrates tissue easily but is not as difficult to remove as a porcupine quill, enabling design of less-painful needles for injections. The researchers are now working on making quill-inspired adhesives from biodegradable materials, which could be broken down inside the body after they are no longer needed.

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