 | |
|
Porcupine a muse for needle design
Porcupine quills penetrate the skin easily,but are extremely difficult to pull out.Boffins plan to use this to develop new types of adhesives,needles and future medical devices Anyone unfortunate enough to encounter a porcupines quillsknowsthatoncetheygo in,theyareextremelydifficult to remove.Researchers at Massachusetts Institute of Technology and Brigham and Womens Hospital now hope to exploit the porcupine quills unique properties to develop new types of adhesives,needles and other medical devices. In a new study,the researchers characterised,for the first time,the forces needed for quills to enter and exit the skin.They also created artificial devices with the same mechanical features as the quills,raising the possibility of designing less-painful needles,or adhesives that can bind internal tissues more securely. There is a great need for such adhesives,for patients who have undergone most types of gastric or intestinal surgery.These surgical incisions are now sealed with sutures or staples,which can leak and cause complications. With further research,biomaterials modeled based on porcupine quills could provide a new class of adhesive materials, says Robert Langer,senior author of the study,which appears in the P r o c e e din g s o f t h e N a tio n - al A c a d e m y o f S cie n c e s. Jeffrey Karp,of Harvard Medical School,is also a senior author of the paper.Lead author is Woo Kyung Cho,a postdoc in the Harvard-MIT Division of Health Sciences and Technology. BORROWING FROM NATURE Aside from stitches and sutures,doctors sometimes use medical-grade superglue to bind tissue together,Karp says.However,thosegluescanbetoxic,or provoke an inflammatory response. To create adhesives that would work in the body without producing adverse reactions,the research team turned to nature for inspiration.We believe that evolution is the best problem-solver, Karp says.In this case,they became interested in the North American porcupine,which has about 30,000 barbed quills.Each quill is several centimeters long;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.Compared to quills with no barbs,the barbed quills require about 50 per cent less force to penetrate muscle tissue.The team then set out to determine how the quills achieve this uniquecombinationofeasypenetration and difficult removal.They found that the tiny barbs at the end of the quill are the key to botheaseofpenetrationandresistance to removal.While the quill is entering tissue,the barbs act to localise the penetration forces,allowing themtotearthroughtissuefibersmuch more easily just as a serrated knife cuts through tomato skin far more cleanly than a straight-edged knife. When it comes to the force required for pullout,the barbs act like anchors that keep the quill from coming out.The force required to pull out barbed quills is four times that required to remove barbless quills. |
No comments:
Post a Comment