Researchers at MIT's Institute for Soldier Nanotechnologies (Cambridge, MA) have developed a nanoscale biological coating that, when coated onto a sponge, can stop bleeding in seconds. If commercialized, this hemostatic coating could contribute to a dramatic increase in survival rates for soldiers wounded in battle.

Led by Paula Hammond, a professor of chemical engineering at MIT, the researchers sought to find a method for quickly minimizing blood loss amid the chaos of the battlefield, thereby improving survival rates; uncontrolled bleeding is cited as the leading cause of trauma death on the battlefield. Although tourniquets and newer approaches, such as fibrin-based dressings and zeolite powders, can be effective in stemming blood flow from battlefield injuries, they also have distinct drawbacks, according to the researchers.

Working to overcome the drawbacks of such existing technologies, the MIT team drew inspiration from methods used in traditional hospital settings and tailored the concepts to suit battlefield needs. To stop bleeding in civilian hospitals, for example, many practitioners employ highly absorbent sponges—many of which are produced by MIT's partner on this project, Ferrosan Medical Devices A/S (Denmark)—that are soaked in a natural liquid clotting agent called thrombin prior to application to the wound. This approach is not practical for the battlefield; however, the researchers realized that it could be suitable for field use if sponges were prepackaged with a blood-clotting agent already coated on them.

“The ability to easily package the blood-clotting agent in this sponge system is very appealing because you can pack them, store them, and then pull them out rapidly,” Hammond says.

To achieve this proposed system, the researchers developed a nanoscale biological coating composed of two alternating layers of thrombin and tannic acid, which is typically found in tea, that are sprayed onto an absorbent material such as the sponges. The resulting film, according to the researchers, features large amounts of functional thrombin that expedite clotting and minimize blood loss. Animal testing demonstrated successful stoppage of bleeding in 60 seconds using the researchers' precoated sponges. In contrast, sponges that were not coated with thrombin took at least 150 seconds to stop bleeding while gauze patches had not stopped bleeding by the end of the 12-minute test, according to the researchers. Although ideal for battlefield use, the coated sponges could improve patient care in civilian settings as well.