While in circulation, red blood cells (RBC) need to elastically undergo large deformations without lysing, an ability that may be compromised by cell membrane damage. Such can be tested in vitro by subjecting an RBC sample to external mechanical stress, e.g. through bead milling or oscillation of an object in a sample. In addition to controlling frequency and duration of oscillations, this approach can be further tailored by bead selection/design.
This work studies effects of different beads in creating qualitatively as well as quantitatively different shear stresses when oscillated in a sample containing RBC.
Identical, diluted RBC samples were stressed via bead milling using different beads, with hemolysis profiles developed in each case.
Bead dimensions significantly impacted induced stress, both in magnitude as well as type, as reflected by hemolysis under respective conditions. Specifically, cell protection (from lysis) afforded by albumin (when present in the medium) showed a complex dependence on bead length and diameter, with the effect seemingly indicative of multiple combined stresses induced by the bead oscillation. The effect is described as an interplay of stresses generated in bead wake in combination with those generated in the annulus.
Bead oscillation based mechanical fragility (MF) profiling of RBC presents a useful tool for exploring effects of different shear stress types for various potential applications for assessment of blood damage, and particularly of sub-hemolytic red cell damage.