Eventually, the bandages could even be placed in home and car first aid kits. How it works The concept for the new bandage is based upon how the body seals blood vessels through a sequential process called hemostasis. Upon injury, blood cells called platelets adhere to damaged blood vessels and each other, releasing chemicals that stimulate vasoconstriction to reduce the blood flow at the site of injury. This new bandage is a synthetic mesh coated with these two proteins in an inactive freeze-dried state. The dried protein mix is activated to coagulate on contact with water, so once the bandage is applied to a bleeding wound, a scab forms in seconds.
Blood clotting is a physiological process involving a cascade of biochemical events.
The cascade is a series of steps by which an activated protease cleaves a portion of another inactivated protease, thereby activating it so it can cleave and activate another protease, and so on. At the end of this enzymatic cascade is the proteolytic cleavage of prothrombin into thrombin. Because fibrin seals wounds as it is formed from fibrinogen, for a bandage to take advantage of these proteins both fibrinogen and thrombin have to be brought together at the site of the wound to work effectively as an instant bandage. Early attempts to make a fibrin sealant were problematic because thrombin prematurely digested the fibrinogen into fibrin when the two were mixed. The new bandage works around this issue by first freeze-drying the proteins into a fine powder in a process called lyophilization, for thrombin is inactive unless in solution.