Researchers at the Massachusetts Institute of Technology (MIT; Cambridge, USA) and Ferrosan Medical Devices (Ferrosan; Soeborg, Denmark) developed a nanoscale biological coating that consists of alternating layers of thrombin--a natural clotting protein--and tannic acid. The combination yields a biological film containing large amounts of functional thrombin that when sprayed onto a material, such as a sponge, can be used as a battlefield dressing. A key advantage of the spray method is that it allows a large amount of thrombin to be packed into the sponges, coating even the interior fibers. Once sprayed, the sponges can be molded to fit the shape of any wound and subsequently be stored for months before use.

In laboratory tests conducted at Ferrosan using a porcine spleen bleeding model, the coated sponges were applied to wounds with light pressure (from a human thumb), for 60 seconds, and stopped the bleeding within that time frame; sponges lacking thrombin required at least 150 seconds to stop the bleeding. For comparison, a simple gauze patch, applied for 12 minutes (the length of the experiment), failed stop bleeding. The researchers have filed a patent application on the technology, as well as on similar sponges coated with the antibiotic vancomycin. They are now working on combining the blood-clotting and antibiotic activities in a single sponge. The study describing the technology and the test results was published on December 27, 2011, in the online edition of Advanced Materials.

“Now we have an alternative that could be used without applying a large amount of pressure and can conform to a variety of wounds, because the sponges are so malleable,” said lead author Anita Shukla, PhD, of MIT. “Both materials are already approved by the US Food and Drug Administration, which could help with the approval process for a commercialized version of the sponges.”

Traditional methods to halt bleeding at the battlefield, such as tourniquets, are not suitable for the neck and many other parts of the body, causing researchers to try alternative approaches, all of which have disadvantages. Fibrin dressings and glues have a short shelf life, can cause an adverse immune response, while zeolite powders are difficult to apply under windy conditions, and can cause severe burns. Another option is bandages made of chitosan, a derivative of the primary structural material of shellfish exoskeletons. Those bandages have had some success but can be difficult to mold to fit complex wounds.

Related Links:
Massachusetts Institute of Technology
Ferrosan Medical Devices