The trick is getting the trehalose into the platelets, a task that Crowe discovered to be surprisingly easy. All he had to do was gently heat the platelets and then let them sit in a bath of trehalose solution for several hours; the platelets slowly took the sugar up into their structure. Once the platelets were loaded with trehalose, Crowe freeze-dried them, turning the platelets into a dried powder.
Battle front
Then, using nothing more than water, Crowe and his colleagues rehydrated them. To their delight, they discovered that more than 90% of the platelets were intact and viable. They did observe some slight abnormalities in the rehydrated platelets, but found that they largely acted like fresh platelets, forming clots just like their non-freeze-dried counterparts. “They’re not fully functional platelets, but they’re close enough,” Crowe says. “You just add water and they’re ready to go.” (For comparison, Crowe and his colleagues also freeze-dried platelets that had not been loaded up with trehalose. Most of these platelets completely disintegrated when the researchers tried to rehydrate them, and the few that didn’t had all fused together into a useless clump.)
Crowe’s freeze-dried platelets can be stored safely at room temperature for two years - a drastic improvement from five days. The freeze-dried platelets are currently under study in clinical trials, which Crowe expects to be complete within the next two years. If the platelets pass this test, they’ll be ready to be used clinically. The US Defense Advanced Research Projects Agency (Darpa), part of the Department of Defense, funded much of Crowe’s research and is particularly eager to get its hands on the platelets, which are usually unavailable to soldiers on the front lines.It would also like to see the work extended to other potentially life-saving substances. Darpa’s hope, Crowe says, “is that everyone going into combat will have in their backpacks a little packet of their own platelets and stem cells and blood cells”.
Crowe recently retired from active research, but there are now a host of scientists and start-up companies that are building upon his work. Some scientists are even taking a genetic engineering approach - rather than loading cells with trehalose from the outside, they’re trying to engineer cells with the genetic machinery to produce the sugar on their own.
Meanwhile, others are using trehalose to preserve DNA in a dry state or create dry vaccines that do not need to be refrigerated. Shelf-stable and easy to transport, such vaccines could be shipped to even the most remote corners of the globe, expanding access to a crucial tool of public health. If trehalose keeps inspiring innovations like these, it could be serious diseases that find themselves all dried up.
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