Plastic-coated platelet could stanch internal bleedingPlastic-coated platelet could stanch internal bleeding

"Emergency treatments for stopping the flow of blood from cuts and other external injuries save thousands of lives each year," say Erin Lavik, associate professor in biomedical engineering at Case Western Reserve University, who heads the research project. "But we have nothing that emergency responders or military medics can use to stop internal bleeding permanently or at least long enough to get a patient to a hospital. There's a tremendous need in the military, where almost 80% of battlefield traumas are blast injuries. In civilian life, there are many accidents, violence-related injuries and other incidents that result in internal bleeding."

Currently, no effective treatments exist that are portable and can stop internal bleeding at the scene, according to a presentation made by Lavik at an annual meeting of the American Chemical Society. At the hospital, however, patients typically undergo surgery and receive donated platelets or something called factor VIIa, which helps with clotting, but both can cause immune problems. Factor VIIa also can potentially cause blood clots elsewhere in the body, not just at the site of bleeding, increasing stroke risk. Other alternatives have been developed in the laboratory, but they've had similar side effects and are not currently used in hospitals.

Lavik's research focuses on platelets that are synthetic versions of the disc-shaped particles in blood that collect on the jagged edges of cut blood vessels and launch the chain of biochemical events that result in formation of a clot that stops the flow of blood. The synthetic platelets are nanoparticles that are designed to stick to natural platelets and leverage quicker and more efficient clotting at the site of an internal wound.

The nanoparticles are spheres that are made of the same medical plastics material used in dissolvable sutures, and they disappear from the body after doing their work. The particles have an outer coating of polyethylene glycol (PEG), the same thick, sticky substance used as a thickening agent in skin creams, toothpastes and other consumer products. Researchers then attach a peptide, or small piece of protein, that sticks to platelets. The end product is a white powder that has a shelf-life without refrigeration of at least two weeks-almost twice as long as the donated natural platelets now administered to control bleeding. Unlike donated platelets or factor VIIa, the synthetic platelets do not require refrigeration.

In tests on laboratory rats, stand-ins for humans in such experiments, the artificial platelets worked better than factor VIIa in stopping internal bleeding and increased survival, says Lavik. Emergency medical technicians or battlefield medics could carry the powder to treat patients immediately. Power would be mixed with water and then injected.

"We are testing these particles in models of blast trauma, spinal cord injury, and preclinical models of trauma," Lavik told Plastics Today. Testing has not yet been conducted on humans.

The researchers acknowledged the National Institutes of Health Director's New Innovator Award, 1DP2OD007338-01 and Department of Defense CDMRP award, W81XWH-11-1-0014.