SIZE-DEPENDENT AND DENSITY-DEPENDENT ELUTION OF NORMAL AND PATHOLOGICAL RED-BLOOD-CELLS BY GRAVITATIONAL FIELD-FLOW FRACTIONATION

Elution of normal and pathological human red blood cells (RBCs) was pe rformed by gravitational field-flow fractionation (GFFF). The reproduc ibility of the retention factor was lower than 10% and elution at high and low flow-rates confirmed the existence of ''lifting forces''. No direct correlation between size and retention was observed for normal RBCs in the absence of density information. Elution of pathological hu man RBCs, known to be modified in shape, density and rigidity, was per formed. The elution parameters confirmed that the retention mechanism of RBCs is at least density dependent but that other factors can be in volved, such as shape or deformity. Moreover, peak profile description parameters (standard deviation and asymmetry) can be qualitatively re lated to some biophysical parameters. Numerous elution characteristics can be linked to cell properties described in the literature and alth ough GFFF appeared to have limited capabilities in terms of size analy sis it appeared to be a versatile tool for studying cell biophysical c haracteristics.