In the early twentieth century, researchers began to examine hemoglobin – the protein responsible for carrying oxygen from the respiratory organs to the rest of the body – in red blood cells. They found that, when isolated from aging cells – whether from human or cow blood, or from genetically engineered sources – free hemoglobin can be rejuvenated, chemically stabilized, and re-infused as a blood “substitute” that can carry oxygen as effectively as red blood cells, but for a much shorter time.
20世纪初，研究者开始考察红细胞中的血红蛋白——负责将氧气从呼吸器官送到身体其他部位的蛋白质。他们发现，从老化细胞中分离出来后——不管来自人血或牛血，还是通过基因工程获得——自由血红蛋白可以重新焕发活力，化学结构稳定，并能作为血液“替代品”用于注射，其携氧效率不输于红细胞，但携氧时间短得多。（无血红蛋白的合成血液替代品，即所谓的氟碳化合物，携氧效率就比较低。）