Advanced delivery systems for oxygen therapeutics: center around red blood cells

Oxygen therapeutics hold great potential as alternatives to red blood cell/whole blood transfusions. The development of hemoglobin-based oxygen carriers began in the 1930s, but, regrettably, none have received FDA approval. This review starts with an overview of red blood cell physiology and then focuses on hemoglobin-based oxygen therapeutics (including modified and encapsulated hemoglobin) as well as red blood cell mimetics, particularly regarding their size and shape. The review also addresses the different approaches to hemoglobin-based oxygen carriers.