Many diseases – like sickle-cell anemia and malaria – are accompanied by changes in the stiffness of red blood cells. And while microfluidic devices capable of sorting blood cells by size exist, few have made microfluidic devices capable of sorting blood cells by their deformability. But a new set of simulations suggests we could do so relatively easily.

Existing devices sort blood cells by size using an array of tiny posts – kind of like a cellular pachinko machine. Through simulation, researchers found that by changing the shape of these posts – specifically by turning them from circles into sharper triangles –¬† they could sort the red blood cells by their stiffness. Because the sharp corners create large local stresses in the fluid, the blood cells get deformed when passing the corner. That ends up deflecting stiffer cells into a different stream. Build a whole array of posts and you can sort the blood cells by their degree of stiffness – ideally allowing you to isolate the most diseased cells. (Image and research credit: Z. Zhang et al.; via APS Physics)

ETA: Added a clarification: some researchers, like Beech et al., have investigated deformability-based sorting devices.