A new blood-clotting material has been developed by a team from University of Maryland in College Park. This is a hydrogel, a Jell-O–like mixture of water and the fibrous polymer acrylamide, with positively charged nitrogen-containing groups. Experiments with blood plasma reveal that the gel kicks into gear a blood-clotting protein known as factor VII, a key player in the cascade of events that leads to coagulation. In experiments where incisions were made in sheep lung and liver tissue, the hydrogel stopped the lung from bleeding in about two minutes, the liver in four to five minutes. The gel is non absorbable by the body and it looks like it would work well as a topical treatment.
Most other hydrogels are based on biological materials such as chitin, a structural component found in the cell walls of certain fungi, the beaks of squid and the shells of lobsters and crabs. While these materials break down in a friendly manner inside the human body, they are also more easily contaminated by viruses and other microorganisms than synthetic gels are and can trigger an allergic response in some people. These biobased hydrogels cost US$400-500 per application. Estimates suggest that the new gel would cost less than US$10 per application.