Posted by Brigham and Women's Hospital January 17, 2013
The medical tape that physicians use today is quite good at keeping medical devices attached to the skin. Unfortunately, that same sticky tape also can be quite hard to get off – particularly when used on newborns or elderly patients – which often results in severely damaged skin.
But thanks to a little green lizard, an eight-legged arachnid, and researchers at Brigham and Women’s Hospital (BWH), patients may soon benefit from a new type of medical tape that holds strong when you need it to, but also peels off easily.
The Institute for Pediatric Innovation established the need for such an adhesive after surveying neonatal clinicians nationwide. Then they asked Jeffrey Karp, PhD, BWH Division of Biomedical Engineering, Department of Medicine, and Robert Langer, PhD, Massachusetts Institute of Technology, to develop it.
As they often do, Dr. Karp’s team found inspiration in nature.
Geckos are colorful lizards that have the uncanny ability to climb smooth, vertical surfaces without either slipping or getting stuck to the surface. And if you’ve ever stayed at a tropical resort, it’s not unusual to see them scoot across a ceiling. The key to this easy-on, easy-off ability appears to lie in the gecko’s uniquely designed toes, not any sort of sticky fluids. Scientists believe that the patterned rows of spatula-like ridges on their toes create an attractive force between surfaces and their feet. And when they want to remove their feet from a surface, they simply flex their toes inward (away from the surface), which reduces the force by changing the angle between the ridges and the surface, and then easily peel their feet away.
Karp’s team also considered the method by which spiders avoid being caught in their own web. They simply alternate zones of sticky silk and non-sticky silk, and carefully avoid the former.
Thus inspired, instead of patterning an adhesive surface layer that contacts the skin – which others have tried without success – Karp’s team developed a special three-layered tape. The top layer and bottom layers are similar to today’s standard medical tape – a sticky bottom layer and a non-sticky top layer. The middle layer, however, is unique. The team used a laser to etch a special pattern in the middle layer that enables the tape to maintain a strong hold until a peeling force is applied – just like a gecko. The middle layer also is non-adhesive, like the spider’s lair, making the tape even easier to remove.
“Current adhesive tapes that contain backing and adhesive layers are tailored to fracture at the adhesive-skin interface. With adults, the adhesive fails, leaving small remnants of adhesive on the skin. With fragile newborn skin, the fracture is more likely to occur in the skin, causing significant damage,” says Karp. “Our approach transitions the fracture zone away from the skin to the adhesive-backing interface, thereby completely preventing any harm during removal.”
- Karp’s lab: The Laboratory for Advanced Biomaterials and Stem-Cell Based Therapeutics
- More nature-inspired research: Capturing Cancer Like a Jellyfish
- Bryan Laulicht, postdoctoral fellow co-advised by Karp and Langer, and his award-winning research role: Finding an adhesive that protects vulnerable skin