[Recent progress and trend in the development of artificial blood]

Recent Progress and trend in the development of the blood substitutes, both of hemoglobin based substitute and totally synthetic one, are overviewed to apply them as an artificial blood. In response to the requisites as oxygen carriers, characteristics and present status are summarized for hemoglobin vesicles, modified hemoglobin (such as conjugated-, polymerized-, crosslinked-hemoglobin) including recombinant from gene-engineering, and totally synthetic oxygen carriers. Concentrated Hb encapsulated with thin phospholipid membrane (hemoglobin vesicle) transports the sufficient amount of oxygen with excellent solution properties. In vitro and in vivo data, and storability in frozen or dry states are introduced. Oxygen transporting ability in blood stream of the totally synthetic carrier (lipid-heme embedded in the bilayer of a phospholipid vesicle) is demonstrated by exchange transfusion tests in animals. Current status of their development including phase-I clinical results is also introduced as well as unsolved issues and future perspectives of the artificial blood.