Complex sentence: There is additional longer range research on true artificial red and white blood cells which could theoretically compose a blood substitute with higher fidelity to human blood.shrey, oxygen transport, one function that distinguishes real blood from other volume expanders, has been very difficult to reproduce.
Split into simpler sentences: There is additional longer range research on true artificial red and white blood cells which could theoretically compose a blood substitute with higher fidelity to human blood. Unfortunately, oxygen transport, one function that distinguishes real blood from other volume expanders, has been very difficult to reproduce.