This week it was announced that a blood substitute based on
their alternative theories is looking promising in an early
trial. Developing a suitable blood substitute for people has
been a major effort for decades. An artificial blood would
relieve shortages and prevent patients being infected by
contaminated supplies. Ideally, it could be given to anyone
without triggering rejection, so accident victims could be given
transfusions immediately without testing to see what blood group
they are. And a long-lasting form that does not need to be kept
cold would be ideal for use in disasters, wars and remote areas.
But company after company has worked on substitutes only to
abandon their efforts because of safety concerns. Most blood
substitutes are based on various forms of haemoglobin, the
protein that carries oxygen in most animals. The guiding
principles are that artificial blood should be thinner than real
blood, so that it circulates easily, and have a low affinity for
oxygen, so that it releases oxygen easily