Blood bulky muscular legs. In insects, the blood (more properly called hemolymph) is not involved in the transport of oxygen. (Openings called tracheae allow oxygen from the air to diffuse directly to the tissues.) Insect blood moves nutrients to the tissues and removes waste products in an open system. Other invertebrates use respiratory proteins to increase the oxygen-carrying capacity. Hemoglobin is the most common respiratory protein found in nature. Hemocyanin (blue) contains copper and is found in crustaceans and mollusks. It is thought that tunicates (sea squirts) might use vanabins (proteins containing vanadium) for respiratory pigment (bright-green, blue, or orange). In
Genetically engineered blood protein and a substance of choice, such as a small-molecule therapeutic agent or an antibody. The modifications leave the cells and their surfaces otherwise intact. One application is to engineer red blood cells into drug-delivery vehicles. Mature red cells carry no genetic material, potentially presenting fewer safety risks than other gene and cell therapies. Human red blood cells circulate for as long as four months, meaning they could potentially form the basis of long-term therapies. The cells move throughout body via the bloodstream and are unnoticed by the immune system. Genetically engineered blood Genetically engineered blood is blood that has