Biological Coating That Stops Bleeding Instantly

Biological Coating Stops Bleeding Instantly MIT engineers have developed a spray coating that can stop bleeding very rapidly, opening the way to a breakthrough that could save the lives of soldiers suffering traumatic wounds on the battlefield. This nanoscale biological coating contains thrombin, a clotting agent found in blood, and tannic acid, and can be sprayed in layers onto sponges. When these sponges are applied to wounds with light pressure, bleeding can be stopped much faster compared to using uncoated sponges. MIT engineers have developed a nanoscale biological coating that can stop bleeding almost instantly, potentially significantly increasing survival rates among soldiers wounded in combat. Financed by MIT's Institute for Soldier Nanotechnologies and Ferrosan Medical Devices A/S, a Denmark-based company, researchers led by Paula Hammond created a spray coating containing thrombin, a clotting agent found in blood. Sponges coated with this material can be stored reliably and easily transported by soldiers or medical personnel. David H. Koch Professor of Engineering Hammond noted that the blood clotting agent in this sponge system has an appealing easy-packaging feature, saying "You can package them, store them, and quickly pull them out," indicating that the sponges could play an important role in civilian hospitals as well. Hammond and colleagues described the technology they developed in the online edition of the Advanced Materials journal. The paper's lead author is Anita Shukla (PhD '11), currently a postdoc at Rice University. Uncontrolled bleeding is among the leading causes of traumatic death on the battlefield. Conventional methods used to stop bleeding, such as tourniquets, are not suitable for the neck and many other parts of the body. In recent years, researchers have tried alternative approaches, all with certain drawbacks. Fibrin dressings and adhesives have a short shelf life and can cause adverse immune reactions, while zeolite powders are difficult to apply in windy conditions and can cause severe burns. Another option is bandages made from chitosan, a derivative of the primary structural material of the exoskeletons of crustaceans. These bandages showed some positive results, but can be difficult to shape to fit complex wounds. Many civilian hospitals use highly absorbent gelatin sponges produced by Ferrosan to stop bleeding. However, these sponges must be dipped in liquid thrombin immediately before application to the wound, making them impractical for use on the battlefield. Hammond's team proposed the idea of pre-coating sponges with a blood-clotting agent, so they would be ready for military or civilian use when needed. To accomplish this, researchers developed a nanoscale biological coating consisting of two alternative layers sprayed onto a material like the sponges used in this study. Researchers discovered that layers of thrombin, a natural clotting protein, and tannic acid, a small molecule naturally found in tea, created a film containing large amounts of functional thrombin. Shukla notes that both materials are approved by the U.S. Food and Drug Administration, and this could help in the approval process for a commercialized version of the sponges. David King, a trauma surgeon and surgical trainer at Massachusetts General Hospital who was not involved in the research, says an important advantage of the spray method is that it allows large amounts of thrombin to be deposited into the sponges and even coat the inner fibers. King concluded, "All current hemostatic materials suffer from the limitation of being able to deliver a sufficiently dense package of hemostatic material to the bleeding site. This new material is exciting because of this." The sprayed sponges can be stored for months before use. The sponges can also be shaped to fit any wound. Shukla said, "Now we have an alternative that can be used without applying large amounts of pressure and can adapt to various wounds, because the sponges are quite soft." In animal testing at Ferrosan, coated sponges were applied to wounds with light pressure (with a human finger) for 60 seconds and stopped bleeding within that time. Uncoated sponges required at least 150 seconds to stop bleeding. A simple gauze applied for 12 minutes (the duration of the experiment) did not stop bleeding. The researchers filed a patent application for the technology they developed and similar sponges coated with the antibiotic vancomycin. Hammond's laboratory team is currently working to combine blood clotting and antibiotic activities in a single sponge. Reference: "Hemostatic Multilayer Coatings", Anita Shukla, Jean C. Fang, Sravanthi Puranam, Flemming R. Jensen and Paula T. Hammond, 27 December 2011, Advanced Materials. DOI: 10.1002/adma.201103794. Source