We know that blood is the medium the human system uses to carry oxygen and nutrients to parts of the body that need it. We also know that it’s made of four main parts: white blood cells that aid the immune system, red blood cells that carry oxygen, platelets that help form clots and the blood plasma that these elements are suspended in. We’re still a long way from creating a true lab-grown substitute for our own blood, but there are occasions when artificial blood is a viable – and potentially lifesaving – alternative.
Human blood has a shelf life of up to 42 days and it needs to be kept cool, as it’s prone to infection. Blood transfusions also need to be a compatible blood grouping (eg A, B, AB or O) or there can be dire consequences. Artificial blood cannot replace all the functions of human blood but it can carry oxygen effectively. It has a longer shelf life, doesn’t need to be cooled, can be sterilised and is also blood-type agnostic – so, in other words, any blood type can use it. It’s particularly useful on the battlefield or when there is a shortage of human blood stock.
There are two main types of artificial blood: HBOC and PFC. HBOC (haemoglobin- based oxygen carrier) is made from a living source, either expired human blood, cow blood, genetically modified bacteria that produces haemoglobin or from human placentas.
It resembles blood much more in its colour and consistency than PFC (perfluorocarbons), which is completely synthetic and suspended or emulsified in a substrate, so that it appears milky in colour and is oily to the touch. Both are known as oxygen therapeutics because they can carry oxygen in situations when a person’s red blood cells can’t on their own, such as after losing a lot of blood as a result of a serious trauma.