Blood vessel vessels function to transport blood. In general, arteries and arterioles transport oxygenated blood from the lungs to the body and its organs, and veins and venules transport deoxygenated blood from the body to the lungs. Blood vessels also circulate blood throughout the circulatory system Oxygen (bound to hemoglobin in red blood cells) is the most critical nutrient carried by the blood. In all arteries apart from the pulmonary artery, hemoglobin is highly saturated (95–100%) with oxygen. In all veins apart from the pulmonary vein, the saturation of hemoglobin is about 75%. (The values are reversed in the pulmonary circulation.) In
Genetically engineered blood Genetically engineered blood Genetically engineered blood is blood that has been modified for therapeutic or other purposes. Genetically modifying red blood stem cells allows them to produce specific therapeutic proteins on the surface or inside the cell. The stem cells are taken from mammalian bone marrow and are modified in culture. Before they become mature, mammalian red blood cells eject their genetic material. Culturing cells that produce a new protein of interest requires only a few weeks. Using the sortagging protein labeling technique, the researchers used the bacterial enzyme sortase A to establish a strong chemical bond between the surface