Pan, Doctor, and Philip Spinella, a pediatrician at Washington University Medical School, for example, have created Erythromer, a bagel-shaped artificial red blood cell with a nanometer-sized synthetic packet of purified hemoglobin (taken from expired donated blood) sheathed in a synthetic shell. Unlike regular blood donations, it can be freeze-dried, stored at room temperature for extended periods of time, and injected into any human regardless of blood type. Hypothetically, EMS could keep a bag of Erythromer in ambulances, and reconstitute the powder with water—"like tang," Doctor said—to keep patients alive until they reach a hospital. "It still doesn't come close to all the things blood does," Pan said, comparing Erythromer instead to a sort of internal bandage that stabilizes until proper treatment. "It's a bridge." Erythromer's research lab just moved from mice to rabbit testing, but still has to get through testing on larger animal and non-human primates before human trials for FDA approval. In other words, they still have a long way to go.