Abstract
Blood substitutes are oxygen-carrying fluids that aim to provide an alternative to the transfusion of blood. Strategies for developing such substitutes have involved the production of materials based on the naturally occurring respiratory pigment, haemoglobin (Hb), or synthetic, chemically inert, fluorinated liquids called perfluorochemicals (PFCs). Commercial products in both categories have been developed and some approved for clinical use, primarily to facilitate oxygen supply to tissues during surgery or therapy. The latest research is focused on using microbial and plant ‘cell factories’ to express recombinant Hb, understanding the properties of polymeric Hbs from invertebrate animals, and the use of feedback from stakeholders to inform the development of new educational materials to assist patients to make informed choices on future transfusion options.