Today, the American Red Cross collects red blood cells via individual donation, and then processes and stores them in liquid form. The cells must be used within a month or else they become waste. Research has shown that spray-dried blood cells theoretically are viable for up to 20 years, but researchers are still looking for optimal ways to dry and store them.
“The big picture is, if we have a large supply of these dried blood cells stored, we can stabilize the red blood cell supply for the country while also reducing storage costs and space requirements,” explained graduating senior Arturo Valdivia, who worked with peers Spencer Witter and Xiao-Yue Han toward the realization of this revolutionary process.
“The big idea behind spray drying is that the kinetics of drying are faster than the kinetics of dying,” said Han. “The cells are dried so fast they don’t have time to die.”
The team wanted to find the specific parameters for operating a spray dryer that would result in preserved live cells. They sought answers to questions like “how hot can red blood cells get before they die?” and “what relative humidity is required to achieve optimal results?” Valdivia said the team’s preliminary results demonstrate that red blood cells can withstand temperatures of 50 degrees Celsius for 10 seconds while maintaining near 80 percent viability. Red blood cells dried to less than 20 percent relative humidity result in five percent water content (by weight).
Their results indicate that spray drying is a potentially viable operation for drying red blood cells for long-term storage and preservation. Witter said the team envisions the eventual development of a self-contained stainless steel system to make spray drying red blood cells a viable and ubiquitous practice.
Future teams of students will carry on the work, and their goals will include sizing the drying chamber as determined by the team’s kinetic drying model, determining droplet size distribution, and evaluating morphology of red blood cells after drying.