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[Development and challenge of modified hemoglobins as red blood cell substitutes].

The problems of blood shortage and the virus infection risk of blood transfusion have promoted the study of blood substitutes. Modified hemoglobin has become the focus of the challenges research because of its excellent oxygen carrying ability. To overcome the toxicity effect on direct use of purified native hemoglobin, various modification technologies have been developed, including diaspirin cross-linking, glutaraldehyde polymerization, O-raffinose polymerization, polyethylene glycol conjugation, liposome encapsulation and biodegradable polymer encapsulation. Some of the products have been in clinical trials, and one of the products has been approved in a country for clinical use. Research on red blood cell substitutes in China has also developed fast. This paper provides an overview of the history and current status in development of different hemoglobin-based red blood cell substitutes, especially the problems encountered, the challenges faced, and the prospects in future.