Blood supplies
Getting enough blood has always been a challenge for hospitals. Blood donations are critical, but there have been periodic contaminations of blood supplies. In developing countries contaminated blood costs lives and money, and resources that could be better spent elsewhere are devoted to the testing and monitoring of blood and blood supplies. But Dr Lance Twyman and his team at the University of Sheffield may be on the way to discovering an unusual solution – plastic blood.

Working in the polymer and biomaterials research group, they explore how to get polymers, which are large molecules, to replicate molecules found in nature. Twyman explains, ‘blood is a well-known protein and when we spoke to people we realised that this would be very useful.’ And replicating natural molecules is central to the success of artificial blood, because the body’s defences would normally see it as ‘foreign’ and try and flush it out of the bloodstream.

The body’s motorway
‘We looked at the structure of haemoglobin as it has been extremely well studied’, says Tywman, ‘how its shape reflects the function is well understood. We're not trying to make blood itself, we’re trying to make a fluid which will bind oxygen. One of the most important things that blood does is carry oxygen; it is like a motorway in the body carrying lots of things around.’

The research is getting attention because early work has been very positive. ‘We've done part one of our research,’ says Twyman, ‘and we've proved that it will bind oxygen. And it does bind oxygen, but we need to add some other things to it. It's water soluble so it should be mixable with water.’ Which means it could be stored in dehydrated form for later use in the field. And this is one of the many benefits for emergency units who have to carry blood around; the plastic blood should be easily transportable. And it will have a longer life-span than donated blood, which lasts for about 35 days.

Ultimately Twyman doesn’t see it as a complete blood substitute, ‘it wouldn't replace blood, it would be used as a top-up in emergencies to save lives in earthquakes, warzones and traumas where you have to give blood to casualties immediately to save their lives.’