http://www.technologyreview.com/prin....aspx?id=17597Nanosolution Halts Bleeding
A biodegradable liquid developed at MIT and the University of Hong Kong offers a new way to quickly treat wounds and promote healing.
By Jenn Director Knudsen
A team of researchers at MIT and the University of Hong Kong have developed a biodegradable liquid that can quickly stop bleeding.
Composed of peptides, the liquid self-assembles into a protective nanofiber gel when applied to a wound. Rutledge Ellis-Behnke, research scientist in the department of brain and cognitive sciences at MIT and Kwok-Fai So, chair of the department of anatomy at the University of Hong Kong, discovered the liquid's ability to stop bleeding while experimenting with it as a matrix for regrowing brain cells in hamsters.
The researchers then conducted a series of experiments on various mammals, including rodents and pigs, applying the clear liquid agent to the brain, skin, liver, spinal cord, and femoral artery to test its ability to halt bleeding and seal wounds.
"It worked every single time," said Ellis-Behnke. They found that it stopped the bleeding in less than 15 seconds, and even worked on animals given blood-thinning medications.
The wound must still be stitched up after the procedure; but unlike other agents designed to stop bleeding, it does not have to be removed from the wound site.
The liquid's only byproduct is amino acids: tissue building blocks that can be used to actually repair the site of the injury, according to the researchers. It is also nontoxic, causes no immune response in the patient, and can be used in a wet environment, according to Ellis-Behnke. A paper outlining the findings is available online and will be published in the December issue of Nanomedicine.
Ellis-Behnke believes that first responders, say, on a battlefield or at a traffic accident, will save more lives with the nanosolution. Yet the most significant application may be in surgery, he says, especially on the liver and brain.
In fact, as much as half of the time during any operation is spent "doing some sort of bleeding control," says Ellis-Behnke. Consequently, such a liquid could "fundamentally change the pace of the operation."
Ram Chuttani, director of endoscopy and chief of interventional gastroenterology at Beth Israel Deaconess Medical Center in Boston and assistant professor of medicine at Harvard Medical School, is familiar with their research. "Where I see huge applications is in patients who present with gastrointestinal bleeding," he says. "[Right now,] there's no ideal agent to endoscopically manage gastrointestinal bleeding."
"Technologically, this would be one of the easiest things for us to use," Chuttani adds. "It's an exciting agent, a very exciting agent...that's still quite far away. I'd definitely be an early adopter."
The researchers don't yet understand how the nanosolution works to stop bleeding, beyond that it doesn't clot the blood. "Maybe it's creating a nanoscale patch and knitting the materials back together," says Ellis-Behnke, adding that "this is just speculation." Clinical trials on humans are at least three years away, he says.
The research was funded by the Deshpande Center for Technological Innovation at MIT as well as the Technology Transfer Seed Fund of the University of Hong Kong and the Research Grant Council of Hong Kong.
The U.S. military already uses several agents to stop bleeding, including ones made by Z-Medica and HemCon. Z-Medica of Wallingford, CT, uses zeolite-based agents in its pourable products, called QuikClot, and bioactive glass. HemCon of Tigard, OR, uses an organic substance called chitosan in its bandages.
Both QuikClot and bioactive glass, a silica- and calcium-based material, are porous, and thus work like a sponge to mop up blood and adhere to tissue at and around the wound site.
The chitosan in HemCon's bandages binds to tissue and seals wounds. (Chitosan is found in shrimp shells, but extensive tests have shown that people with shellfish allergies don't suffer allergic reactions to chitosan, according to HemCon's president and CEO, John Morgan.) HemCon plans to sell a consumer version of its product next year.
"Both [Z-Medica and Hem-Con's products] have saved lives in my hands," says Captain Peter Rhee, a military trauma surgeon based at the Los Angeles County Medical Center, who oversaw the first study using pourable agents to halt bleeding on animals.
The liquid solution made by the MIT and University of Hong Kong researchers could offer several advantages, however. One is speed. In studies, the nanoliquid took only seconds to work, while competing products take around two minutes. The nanoliquid can also be used on a wound of any shape, unlike HemCon's square bandages, which don't fit over oddly shaped gashes. And the nanoscale solution doesn't have to be removed from the patient, unlike Z-Medica's bioactive glass, which cannot remain at the wound site indefinitely.
Copyright Technology Review 2006.
