Blood is probably not the first thing we think of when considering the most important medical breakthroughs or technologies. You may think that something like a working artificial kidney or heart would have the biggest impact. Of course, these would be world-changing developments by themselves, but we often overlook one essential part of our bodies that we can’t do without – blood.
Almost every major medical intervention requires a supply of extra blood. You don’t need to lose much of this stuff in order to be in trouble, and even routine surgeries may need blood to be a success. So it’s no surprise that artificial blood or “blood substitutes” are a hot area of research. At the moment, there isn’t a total artificial replacement for human blood, but as soon as the problem is cracked, millions of people will survive who would otherwise perish.
The problem is that blood isn’t just a red fluid. It’s an incredibly complex, multi-part fluid that does so much in the body that it’s not strange to think of it as one of the most critical components of the body. There are a lot of anatomical structures that you could live without. Your arms and legs are not strictly necessary, for one thing. You could lose a lung, a kidney, and an eye and still keep on living. Unbelievably, there are people alive today who literally have only half a brain and are none the worse for it.
Sure, it would suck to lose all these things, but if we took just 20% of your total blood volume out, that’s enough for a life-threatening crisis. Your blood is a conduit for energy and immune function. Anyone who has even a basic understanding of how much it actually does will also understand how challenging it is to try to replicate it.
Blood Substitutes over Donations?
At the moment the main way to get blood for those that need it is to use donated blood from other human beings. There are many reasons not to do this. First of all, it represents a minor but real risk to those donating blood. Every time you stick a needle in someone you run the risk of infection or another complication. It also doesn’t help that people who donate blood may be carrying all sorts of blood-borne diseases.
Detection systems are now pretty good, but it’s still possible to transmit something serious, such as HIV, through blood transfusions. This is especially true in developing nations where testing and controls may not be up to the same standards as developed nations enjoy. About 10 to 20 transfusion-related deaths occur for every million units of donated blood in the USA. Not a great many, but still 10 to 20 too many.
Aside from that, there’s just the pure expense of sourcing, extracting, testing, transporting, and storing human blood. Hospitals are always subject to a rolling window of blood supply. If you have a rare blood type you’re in even bigger trouble; blood donation organizations often have to beg people with certain blood types to donate. The ability to mass produce a total replacement for blood would solve these problems almost immediately.
Bit by Bit
The good news is that we don’t always need to replace blood as a whole. Most blood transfusions are actually partial transfusions. They may only contain red blood cells, platelets, or just plasma, for example. While we don’t yet have a way to produce the oxygen-carrying part of blood without donations, other aspects of blood can already be substituted. So let’s look at the work that’s been done in the area of artificial blood products.
For example, 55% of human blood is plasma. This is the carrier fluid for the other component. It contains nutrients, chemicals, and other bits and pieces. The reason you’re in trouble when you’ve lost a fifth of you blood volume is that there just isn’t enough fluid in the system to let the heart pump properly. Since our red blood cells have extra oxygen-carrying capacity, we can actually lose two thirds of them and be OK, as long as we’re not exerting ourselves. So artificial plasma can already save many lives in danger from blood volume loss. These “volume expanders” are carefully mixed chemical solutions that can replace this primary part of blood.
Artificial Red Blood Cells
So what about red blood cells? Even if we can get along temporarily with just a third of them until the body can make more, there are plenty of situations where that’s not a real option. This is where whole blood transfusion has to be relied on in emergencies or during surgeries. There are also plenty of diseases that damage the cells themselves or damage our ability to produce them.
So will we be able to make red blood cells one day? It does look like this will be the case. This is where the idea of “respirocytes” comes in. They don’t exist yet, but the idea is that these tiny machines will have many times the oxygen-carrying capacity of red blood cells. This would mean that a much smaller volume of these could do the work of many more red blood cells. So if someone had a traumatic injury you wouldn’t need to infuse much of the stuff to save them from oxygen deprivation damage.
The field of nanotechnology will still have a long way to go before respirocytes are even a possibility. If we do manage to do it, you may see some amazing augmentations to human abilities. You’d be able to hold your breath for 20 minutes, or sprint for 15 minutes straight without taking a breath!
Using the Real Thing
Of course, we don’t have to make red blood cells from scratch. Why not just use biotechnology to mass produce human red blood cells without a donor? That’s exactly what the solution-leader in blood production is today. Recently scientists have made a breakthrough in the mass-production of red blood cells using stems cells. While it still very expensive, scaling it up will reduce the cost and eventually may remove the supply problem completely.
It’s going to be exciting to see how far the development of artificial blood technology will go. Once this was a substance that people considered magical and holy. The idea of transfusing it from one person to another was abhorrent. Now we may be making this almost-magical stuff ourselves – a miracle indeed.