Medical gauze hasn't changed much since World War I: Medics can only stuff it into a gushing wound and pray.

Now chemists have infused cotton gauze with nanoparticles, giving it a vastly improved ability to halt blood loss -- even in tight spots like the neck or groin where it's hard to apply pressure. The new material could help save lives on the battlefield and in civilian situations, where trauma victims often bleed to death before they can be transported to a hospital or other medical facility.

"We are currently testing bandages because hemorrhage is a leading cause of death in military trauma patients," says Richard McCarron, head of trauma and resuscitative medicine at the Naval Medical Research Center in Silver Spring, Md. "The recent tests with Combat Gauze indicate that it decreased blood loss and improved survival."

In this video, researchers test Combat Gauze on an anesthetized pig. The pig's aorta is slit, then the gauze is applied for a brief time, which stops the flow of blood. Warning: Content may be disturbing to some viewers.

For more, visit Wired.com video.

The lifesaving fabric McCarron refers to is made by Z-Medica, a medical products company based in Connecticut. According to Z-Medica CEO Ray Huey, the new product has already saved two lives.

"In 2002, following the September 11 attacks, the military was looking at new technologies to stop bleeding," Huey says.

When the Navy conducted a test of high-tech medical products, Huey says the clear winner was Z-Medica's first product, QuikClot, a grainy powder that can be dumped into gushing wounds to stanch bleeding. Shortly thereafter, the military started sending it to troops in Iraq and Afghanistan.

Unfortunately, the soldiers reported some problems: QuikClot would get hot when it came into contact with blood or water, and in some instances it caused serious burns. While burns are better than bleeding to death, it still wasn't an optimal solution.

The Navy turned to Galen Stucky, one of the top names in inorganic materials research, to work out the kinks. Stucky and several graduate students were able to solve the heating problem, file several patents, and form a business relationship with Z-Medica.

Ironically, the solution to the heating problem lay in replacing QuikClot with a material that has been used in medical tests for more than 50 years. The key ingredient in the new gauze is kaolin clay, which is often used to make pottery and happens to be rich in aluminosilicate nanoparticles -- which trigger blood clotting.

"Kaolin clay has been used since the 1950s as an activating agent for a clotting test that medical doctors routinely perform," says graduate student April Sawvel, who worked on the project. "We tested it against the original granular QuikClot and discovered that it worked just as well, but without the large heat release associated with the original QuikClot formulation."

Although researchers have raised concerns about the safety of nanoparticles, the aluminosilicates found in kaolin clay have been used on the human body, and introduced into it, for eons. Furthermore, by triggering blood clotting, the nanoparticles should effectively trap themselves at the site of the injury -- so they don't wind up wandering deep into the body.

Immediately following the researchers' discovery, Z-Medica quickly moved to combine the clay with gauze, making it much easier to use.

"We immediately started looking at ways to impregnate gauze with this material," Huey says. "We very quickly prototyped some material. When I say very quickly, I mean within less than two weeks."

Less than a year later, QuickClot Combat Gauze is in the hands of Special Forces operators, the Coast Guard and emergency-room doctors.

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