Blood clot on a plaster. Coloured scanning electron micrograph (SEM) of a sticking plaster used on a cut. Red blood cells (erythrocytes) can be seen in a fibrin mesh (brown). Fibrin is a protein formed from fibrinogen during the clotting of blood. It forms a fibrin mesh that disrupts the flow of blood thus preventing additional blood loss from the site of the wound. Sticking plasters (blue) are made of absorbent material and help to assist in stopping bleeding and can keep injuries clean, dry and infection free during healing. Magnification: x190 when printed at 10 cm wide