A close up of sticky tape that could replace sutures is broken down in conditions that mimic the inside the body. The elastomers and iridescent tape (bottom) is covered with nanoscale pillars and biocompatible glue.

Researchers at MIT have developed a stretchy, biodegradable tape that could replace surgical sutures and staples. The sticky tape could also be made into drug-delivery patches for placement directly on organs, including the heart. The tape, which has been tested in mice, slowly breaks down inside the body without causing irritation.

Gecko toes are sticky because they are covered with millions of flexible nanopillars, giving them a large surface area. The MIT tape also relies on nanoscale pillars, and a glue, making it a first to show good adhesive strength and safety in animals. It's being developed by Institute Professor Robert Langer and Jeffrey Karp, a bioengineer in the Harvard-MIT Division of Health Sciences, and researchers at two Boston hospitals.

The advantage of such a tape over traditional sutures and staples is that it would be noninvasive and easy to place. Sutures and staples puncture tissue and can cause damage that leads to necrosis, cell death in tissue. And traditional fasteners, such as staples, must be carefully placed along an incision. “You have to realign the tissue with each stitch,” says Karp. Tape could be placed in one motion, potentially shortening the time that patients are on the surgical table. The medical tape could also help doctors during laparoscopic surgeries, which are performed through a laparoscope. “It's difficult to tie knots in small places,” says Karp. “You could have the tape unfold and apply it through a laparoscopic needle.”

The challenge making the tape is that it must be reusable. Medical tape like Karp's must stick only once, but stick strongly. Getting high adhesive strength on tissues is difficult because it's wet, soft, slippery, and rough.

To make the adhesive, a liquid polymer is poured into silicon molds pocked with 200-to-500-nanometer-wide indentations. The molded, hardened polymer is then spin-coated with a biocompatible dextran glue. Applying the tape lets capillary forces pull tissue into the spaces between the pillars, which also have some weak charge attractions. The dextran glue adheres to tissue proteins.

As a drug patch, the tape would be useful on tissues that stretch and contract, such as the heart. After a heart attack, patients often have regions of damaged tissue that don't get enough oxygen. This can lead to heart failure. Injecting a stem-cell-attracting factor into damaged areas of the heart encourages tissue regeneration, while an alternative treatment of piercing the heart can be dangerous. Karp says that a patch of medical tape might deliver these attraction factors just as effectively and put the patient at lower risk.