Human blood can typically only be stored for six weeks. It also needs to be refrigerated, which may be challenging in poor countries or remote locations. A new study, though, could lead to a method of drying blood for long-term room-temperature storage.
A team of scientists at Kentucky’s University of Louisville started by placing red blood cells in a spiral-shaped microfluidic channel, to which they added microscopic bubbles of inert gases, and a fluorescent organic compound known as fluorescein.
The researchers then applied short pulses of ultrasound to the setup. In a process called sonoporation, this caused the bubbles to pop, harmlessly punching small pores in the blood cells’ outer membranes as they did so. Fluorescein molecules were able to enter the cells through those pores, which subsequently closed back up.
Once it was confirmed that the easily-imaged fluorescent molecules had successfully made their way into the blood cells, the scientists repeated the sonoporation process on a fresh batch of cells. This time, however, instead of adding fluorescein, they introduced an inexpensive biocompatible sugar known as trehalose.
It’s naturally produced by “extremophile” organisms living in hostile environments, allowing them to endure long dry periods without experiencing any cell degradation. Among other things, it has also previously been used to create dried versions of live-virus vaccines.
The Louisville team subsequently freeze-dried the trehalose-laden blood cells, stored them at room temperature for 24 hours, and then rehydrated them with de-ionized water. A control group of regular red blood cells, that did not receive any trehalose, were also freeze-dried, stored and rehydrated.
Although the results varied according to factors such as the concentration of gas bubbles used, it was found that overall, a much higher percentage of the treated cells were still viable once the process was complete. The scientists are now looking at ways of increasing that success rate, to the point that the technique can enter clinical use. It is hoped that the freeze-dried blood could ultimately be stored for years at a time.
The research is described in a paper that was recently published in the journal Biomicrofluidics.
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