The ultra-sticky feet that allow gecko lizards to climb walls and hang from ceilings have inspired scientists to create waterproof adhesive bandages that may offer a new way to patch up patients during surgery.
Researchers at the Massachusetts Institute of Technology said in a study released today that the bandages feature the same kind of nano-scale hills and valleys and sticky surfaces that allow the spunky lizards to cling wherever they want.
Unlike the geckos, however, the bandages are meant to stay in place, said Jeffrey Karp, one of the project’s lead researchers. Plus, the glue that coats the underlying structure is designed to stick to living tissue.
“It’s kind of helpful if you think of it as an internal Band-Aid,” said Karp, an instructor of medicine at Boston's Brigham and Women’s Hospital and Harvard Medical School.
Although trials have been limited to tissue samples from pigs and experiments in live rats, they’ve been favorable enough that Karp envisions human applications in as little as two to five years. A surgical adhesive tape made from the material could replace sutures and staples, he said. It could help prevent abdominal adhesions or fix internal leaks that occur during bariatric surgery, for instance.
“There are a lot of meshes and membranes, but there’s nothing that’s a tape-based medical adhesive,” said Karp, who is also a faculty member at the Harvard-MIT Division of Health Sciences and Technology.
The study was released in the Proceedings of the National Academy of Sciences.
Tiny toe hairs let geckos stick
It’s been nearly a decade since researchers developed the first dry adhesives based on the structure of gecko feet — the MIT researchers refer to them as “paws” – that rely on millions of tiny toe hairs to attach to surfaces.
In 2000, scientists in Kellar Autumn's laboratory at Lewis and Clark College in Portland, Ore., were the first to discover the secrets of the gecko's superior stickiness.
Other research teams have focused on mimicking the gecko’s ability to stick and un-stick its feet as it scampers across surfaces. A team led by Northwestern University's Phillip Messersmith has combined the structure of gecko footpads with a water-resistant glue produced by mussels to create a strong, reversible adhesive they dubbed “geckel.”
But Karp said his 21-member team is the first to develop a material suitable for medical uses. The bandages have to be biocompatible, biodegradable and elastic enough to be used on internal organs, he noted.
The key turned out to be development of a special “biorubber” created by Karp and Robert Langer, an MIT professor who also lead the study, which was funded by a $1.3 million grant from the National Institutes of Health. The scientists molded the biorubber based on configurations from the gecko feet and then coated it with a thin sugar-based glue.
The MIT researchers believe the bandages also will be able to be coated with drugs, such as anti-inflammatories or antibiotics, or even with homing targets for stem cells that could make them even more useful.
Their work has drawn praise by fellow gecko researchers like Autumn. He noted that the MIT bandages use a structure more primitive than actual gecko toes, but with the interesting addition of the sugar-based glue.
"This is exciting because it shows that we can go beyond nature to engineer designs that never evolved and suggests that gecko adhesives will have broad application in medicine in the future," he said.
A help in the operating room
Surgeons unfamiliar with the research said the gecko-inspired bandages could come in handy in the operating room. Dr. Harvey Sugerman, past president of the American Society of Metabolic and Bariatric Surgery, said it might be more useful than existing techniques for repairing leaks during obesity surgery.
“They’re difficult,” he said. “The stitches don’t hold very well and they often break down and re-leak ... This product would be needed, if it’s available.”
Availability will depend on how soon Karp and his team can pick an application and design and test a bandage to match. And then there’s the matter of what to call the material, which turns out to be a light-reflecting, rainbow-hued tape.
“Geckel” is good, but it’s already taken.
“A name?” said Karp. “That’s up for grabs.”