Present Situation of the Development of Cellular-Type Hemoglobin-Based Oxygen Carrier (Hemoglobin-Vesicles)

Many researchers have tested a hemoglobin (Hb) solution as a possible oxygen carrier after discovering that one Hb molecule contains four hemes that bind and release oxygen reversibly, and that blood type antigens are expressed on the surface of red blood cells (RBCs). However, various side effects emerged during the long development of Hbbased oxygen carriers (HBOCs). The physiological significance of the RBC structure is undergoing reconsideration. Fundamentally, excessive native Hb molecules are toxic, but encapsulation can shield this toxic effect. So-called liposomeencapsulated Hb or Hb-vesicles that mimic the cellular structure of RBCs have been developed for clinical applications.