Figure 4.

Sequence of red blood cell (RBC) assembly and deformation during the creation and storage of dried blood spheroids on hydrophobic paper substrate. (A) Within <30 min of drying the spheroids, solvent evaporation results in the bridging between individual RBCs, which marks the onset of their self-assembly process. (B) The peak of the RBC self-assembly process occurs at 60 min drying time for 10 µL blood drop where the RBCs aggregate to form the stable rouleau conformation. (C) Hemolysis of RBC at the spheroid’s surface leads to the deformation of the rouleau conformation, which commences at 80 min of drying time. (D) By 120 min in the spheroid’s drying process, all RBCs at the surface of the spheroid lyse due to excessive hemolysis, which leads to the formation of the passivation layer at exterior of dried blood spheroid. (E) Although no RBCs are detected at exterior of the spheroid at 120 min, intact red cells are still detected at the interior bulk of dried blood spheroid even after 2880 min storage under ambient conditions.