Blood is life. Every two seconds, someone in the United States needs a blood transfusion, but donations are low. Only 10% of the 38% of people who could donate blood actually do. If you’ve ever wondered why scientists don’t just create a synthetic blood to substitute the real thing, they’ve been trying. For over half a century. It turns out creating artificial blood is very difficult. Several major medical companies like Baxter and Biopure have simply given up, but many are still searching for the holy grail.
Artificial blood has to do three things: transport and deliver oxygen, but not hurt the patient. The problem is the hemoglobin, which can trigger heart attacks, so none of the results have been considered safe enough for human use in Europe or the United States. In 2013, a study in Romania seemed promising. The team made blood from water, salt, albumin, and an iron protein from marine worms, specifically, hemerythrin. This protein was in charge of the oxygen transport and storage and was able to remain safe when under stress. No other protein had been able to do that and instead turned toxic in the body. The last news out of Romania about this blood substitute is that they were testing it on mice.
Stateside, a team has taken a different approach to problematic hemoglobin. Instead of trying to adjust it, they’ve encased it in a synthetic polymer. When coated this way, the hemoglobin won’t cause heart attacks. It’s also engineered to sense blood pH, so it gets oxygen where it’s high – like in the lungs – and releases it when pH is low. This substitute is known as ErythroMer, and if successful, it could have a huge impact on medicine.
In areas where the blood supply isn’t safe, artificial blood would be a game changer. In Nigeria, blood transfusions cause the second highest number of HIV infections, so clean artificial blood is needed. Since ErythroMer is a powder, it could also be transported much faster than regular blood and stored for years at a time. The military has been especially keen on getting artificial blood since a high number of deaths occur just because a soldier bleeds out before getting to a hospital. A powdered blood substitute mixed with sterile water could save a soldier’s life until they get to a place where another transfusion can be performed since artificial blood cells only last a few days compared to the usual four months.
Even though we’re closer than ever to a good blood substitute, there are obstacles. For one, artificial blood cells are tiny compared to normal red blood cells. At about 1/50th the size, experts are worried that the blood would leak into the body’s tissue, which is what happens when someone has a brain aneurysm. Because of risks like this, trials can take decades. ErythroMer has only been testing in mice and just moved to larger animals; it would be a long time before testing on humans is approved. The FDA is wary of blood substitutes, especially since the only blood substitute they’ve ever approved had to be withdrawn from the market. The first people to experience artificial blood are likely those in combat situations or those with very rare blood types who don’t have other options. Even if ErthryoMer or another substitute that comes along is only used in a single capacity, it would still save a lot of lives.