Genetically and chemically tuned haemoglobin-albumin trimers with superior O2 transport efficiency.

Haemoglobin (Hb)–albumin (HSA) trimers were synthesized using five distinct Hb variants in which the structures were genetically and chemically tuned as an artificial O2 carrier and used as a red blood cell (RBC) substitute. The trimers were found to have moderately low O2 affinity (p50 = 23–34 Torr, 37 °C) and high co-operativity, yielding a maximum O2 transport efficiency 1.8-fold higher than that of human RBCs.