The Man With Golden Blood
I like to cook, which usually involves knives. One afternoon I was chopping onions when I unexpectedly removed the tip of my finger. Naturally, I was alarmed at the amount of blood, and I began to wonder if the bleeding would stop but stop it did. Magic? No, your blood has ways of stopping bleeding. Good job, too; it's important stuff.
Blood looks like a simple liquid, but it is complicated and carries out several jobs. You may know that red blood cells are carried around in a liquid called plasma. You may also know that these cells contain a chemical called haemoglobin, which gives them their red colour. These little packets move around your circulatory system, transferring oxygen to where it is needed and returning to your lungs to pick up more.
Also carried in the plasma are your white blood cells. There are many kinds of these, but they protect you from dangerous invaders. They identify foreign organisms, bacteria, viruses, fungi, or transplanted organs. Once identified, they kill and remove the intruders, memorising information about them in case they come back.
Here you can see a white blood cell engulfing and killing bacteria.
Platelets are cell fragments. They form blood clots if you cut yourself, so you don't bleed to death. I was glad of these when my finger finally stopped bleeding.
Plasma is the liquid part of the blood. The other parts float around in it and are carried around your body. Plasma is mainly water with substances dissolved in it. These substances include salts, glucose, amino acids, fatty acids, glycerol, carbon dioxide, urea and hormones. All of these are important for keeping your body working. Glucose, for example, is used for respiration, and your body uses amino acids to build proteins, which are what most of your body is made from.
As you can see, blood is a highly complicated substance, vital for us to stay alive. If you cut yourself badly, you may need a blood transfusion because if you lose too much of your five litres of blood, your organs stop working. Blood transfusions rely on people donating blood, but enough people need to volunteer to donate blood to keep up with demand. Blood can’t be accepted if a donor is on certain medications or has an illness, so there have been occasions when supplies have run low and leading to cancelled operations. Blood also comes in several types, called blood groups which add further complications to blood transfusions. Doctors must ensure that the donor and recipient have compatible blood types. Blood groups exist because there are proteins called antigens on our red blood cells. If you receive blood with the wrong antigens, your immune system attacks, causing the blood to clot.
Karl Landsteiner discovered blood groups in 1901. Before this discovery, doctors had tried blood transfusions but were puzzled that the patient sometimes survived but often died. Landsteiner found that you had to match the donor's blood type with the patient's. Before Landsteiner discovered blood groups, doctors tried other ways of helping patients who had lost blood. Instead of human blood, they tried beer, milk, urine, solutions of haemoglobin or animal blood as a substitute. The last two worked the best but didn't catch on because of problems making and purifying them.
The wars in the early 20th century made blood transfusions more common though there were still problems with supply. In 1947 blood banks began, and people would donate blood for operations and accidents. It can be challenging to collect enough of each blood type, as some are more common than others. Also, sometimes the blood has been contaminated with pathogens. There have been court cases recently brought by people infected by HIV or hepatitis through blood transfusions.
Very few people in the world can have extremely rare blood types. People with 'golden blood' or Rh-null blood are missing a set of antigens belonging to the Rh system. Rh antigens are why each blood group can be called positive or negative; I'm A+ , for example. There are only about 50 Rh-null people worldwide, and because these people can't receive transfusions from any other blood group, they have difficulties getting treatment if they need surgery. Their blood is worth its weight in gold because people with other rare blood groups can be recipients. With no antigens, the recipient's immune system doesn't reject it, allowing vital operations to go ahead.
Thomas is a person with this "golden blood". For many years he has donated his rare blood to help people with rare blood types. Thomas has also donated blood as insurance for himself, as Rh-null people can't have blood from any other group. He can save others, but only the fifty people with the golden blood can help him. He has travelled from his home in Switzerland to other countries to make donations, often at his own expense. Medics store some of Thomas’ donations for when he may need a blood transfusion himself, but a person with a rare blood group may get this blood if they need a transfusion. He has often travelled to other countries to donate; there's less paperwork if he travels compared to sending a pint of blood.
What if we could solve all these problems by making artificial blood, which would be plentiful, free of pathogens, and work on everyone? Some scientists have been working on this, but blood is complicated, and it's difficult to replicate all its functions. A blood substitute needs to be
safe
work with all blood types.
sterile
able to carry oxygen and release it
last a long time in storage
If a patient loses a lot of blood, doctors transfuse plasma. This keeps the amount of fluid high enough for their organs to work but doesn't carry oxygen, so scientists are looking for other solutions. None are perfect.
Perfluorocarbons (PFCs)
These chemicals will carry oxygen when an emulsion is injected into a patient. They can be used on anyone, but you need a lot of the mixture to carry enough oxygen, and they don't fight disease or clot. The mixture doesn't last long in the body, unlike a blood transfusion which lasts about 30 days.
Haemoglobin oxygen carriers
Haemoglobin is the chemical in our red blood cells which carries oxygen. The oxygen attaches to it easily but also comes off easily when needed. This allows haemoglobin to pick up oxygen in our lungs and transport it to our cells. Scientists have taken haemoglobin out of red blood cells and injected it into patients. It works pretty well to help people after operations. The haemoglobin is taken from human donations and cows. It needs to be purified and sterilised before it is ready to be used in patients.
The haemoglobin from cows is easy to get hold of, so there won't be problems with supply. It also seems safe, can be used on anyone, no matter their blood group, and can have a long shelf life.
The problem with haemoglobin outside red blood cells is that it only lasts a few hours in the body. There is an idea that putting the haemoglobin into little lipid bubbles could make it last longer. The bubbles are like the technology that carries the critical parts of some of our COVID vaccines. These lipid bubbles, liposomes, have also been investigated as a feasible way to make artificial blood, but there are problems and obstacles. Perhaps you could be part of a team that finds the solution to these issues.
