A synthetic new gel made of water and the fibrous polymer acrylamide kick into gear the blood-clotting protein known as factor VII, thereby stanching blood flow from deep wounds in just minutes, report researchers from the University of Maryland in College Park.
"You just apply it to the surface of a wound," says Brendan Casey, a biomedical engineer at the university who began investigating polymeric hydrogels in 2007 and presented his latest findings from experiments on sheep at this week's American Chemical Society fall meeting.
Hydrogels are by no means novel, but many are made of biological materials (i.e. chitin, a derivative of glucose found in the beaks of squid and octopus, the shells of lobsters, and the cell walls of certain fungi). The problem is these gels are both expensive--Casey says they cost several hundred dollars a dose because they must be harvested, purified, and stored in specific conditions--and more susceptible to viruses.
But the new, synthetic hydrogel, which Casey says can be made in bulk in a lab for closer to $10 a pop and is robust enough to withstand extreme temperature fluctuations, stopped the bleeding from 2-inch-long and 0.5-inch-deep incisions to sheep lungs in two minutes and to sheep liver in four to five minutes.
"It could be placed in a packet in Afghanistan or the Arctic and there would be no stipulations on shelf life, for the most part," says Casey, who hopes to provide an affordable alternative to bio-hydrogels to help save the vast majority of people who die from blood loss every year in poor countries without easy or affordable access to these coagulants.
Casey says that both the polymer's positive charge and its material stiffness (he says the gel looks like dried Jell-O) cause the clotting, but he warns that more investigation is required before they understand exactly how it works and can bring it to market.