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.