In 1943, Vesta Stoudt was working at the Green River Ordnance Plant, a large munitions factory near Amboy, Illinois. Surrounded by gunpowder and heavy machinery, her thoughts were with her two sons serving in the U.S. Navy at the height of World War II. She worried sick not only about her sons, but also the lives of other American soldiers. One thing was particularly on her mind, though. Among the boxes of ammunition in her factory, Stoudt noticed a flaw that could prove life-threatening.
The boxes of ammunition were sealed with paper tape, then dipped in wax to make it waterproof. The problem was that the paper tape was very thin, which made it very difficult to open them. For soldiers under fire, this was a little more than a nuisance.
As she shook her head, Stoudt had an "aha" moment: Why not seal the boxes with a waterproof cloth tape? After her supervisor ignored her idea, she sent a letter straight to President Roosevelt, who was so impressed with her design and reasoning, he immediately forwarded it to the War Production Board, which began work on a prototype.
The product turned out to be an instant hit. The military called it "100-mile-per-hour tape" because they could use it to fix anything, from fenders on jeeps to boots. To this day, duct tape is the go-to tool of choice whenever we have a leaky pipe or crack that needs to be filled. It's been even used on the International Space Station to seal cracks.
Repairing gut leaks like you would seal pipes with duct tape
MIT engineers, who are well versed in the art of duct taping, thought about applying the same mechanics in a highly wet and sensitive environment like the human gut. They've developed a surgical duct tape that is strong but flexible, as well as biocompatible. It can be easily and quickly applied to an internal wound or virtually any kind of biological tissue to seal tears and cuts.
“We think this surgical tape is a good base technology to be made into an actual, off-the-shelf product,” Hyunwoo Yuk, a research scientist in MIT’s Department of Mechanical Engineering and co-author of the new study, said in a statement. “Surgeons could use it as they use duct tape in the nonsurgical world. It doesn’t need any preparation or prior step. Just take it out, open, and use.”
Like heavy-duty duct tape, the newly devised patch is sticky on one side and smooth on the other. It's based on a 2019 design for a double-sided tape made by the same team led by Xuanhe Zhao, an associate professor of mechanical engineering and of civil and environmental engineering at MIT.
However, the double-sided tape strongly bonded different biological tissues together, which is not something surgeons want -- at all. After gathering feedback, the MIT researchers tweaked the composition and the design of the surgical patch so it's sticky only on one side. It's made from polyacrylic acid, an absorbent material typically found in diapers, which starts out dry but quickly absorbs moisture when in contact with a wet surface. NHS esters were added to the mixture, which binds with proteins in the biological tissue to form stronger bonds. Finally, the adhesive was reinforced with polyvinyl alcohol that stabilized the structure of the tape so it could last for over a month -- enough for a typical gut injury to heal.
“We don’t want the patch to be weaker than tissue because otherwise it would risk bursting,” Yuk says. “We also don’t want it to be stiffer because it would restrict the peristaltic movement in guts that is essential for digestion.”
Once the gut wound heals, the patch eventually degrades without causing inflammation or sticking to surrounding tissues. The tape hasn't been tested in the field, on humans, but experiments with a range of tissues from different model animals have been very promising. This includes applying the surgical patch over colon defects in pigs, which continued to feed normally, with no fever or other adverse health effects.
The idea is to stock operating rooms in hospitals across the world with these sticky patches as a fast and reliable alternative to hand-sewn sutures. The researchers are currently pursuing FDA approval to test the patch in a medical setting and bring their product to the market through a spun-off startup.
“We are studying a fundamental mechanics problem, adhesion, in an extremely challenging environment, inside the body. There are millions of surgeries worldwide a year to repair gastrointestinal defects, and the leakage rate is up to 20 percent in high-risk patients,” Zhao said. “This tape could solve that problem, and potentially save thousands of lives.”
The findings appeared in the journal Science Translational Medicine.