Dissolved Oxygen-Dependent Magnetophoresis of Sickle Red Blood Cells and Proof-of-Concept Separation Using a Magnetic...

Red blood cell (RBC) function is significantly altered in sickle cell disease (SCD) due to the polymerization of sickle hemoglobin (HbS) into polymers under deoxygenated conditions leading to the formation of sickle shaped RBCs. Since magnetophoretic mobility is inversely proportional to hemoglobin (Hb) oxygen saturation, we investigated whether magnetophoresis could distinguish RBCs from healthy donors and those from sickle cell patients. Single-cell magnetophoretic mobilities were measured for 4 healthy and 5 SCD samples using cell tracking velocimetry (CTV) under controlled partial pressures of oxygen (pO₂). Preliminary cell separations were also performed using a Miltenyi LS column under air-saturated conditions. The concentrations and magnetophoretic mobilities of the feed, eluted, and captured cell fractions were quantified with a Coulter Counter and CTV. At a pO₂ of 10 mmHg, sickle RBCs showed statistically significant differences in magnetophoretic mobility compared to healthy RBCs, consistent with known differences in oxygen-Hb equilibria. The magnetophoretic mobility reflects the oxygen-Hb equilibrium and can discriminate sickle from healthy RBCs at low pO₂. Separation studies highlight additional complexity in bulk separation under air-saturated conditions, where both magnetism and sickle cell adhesion contribute. These results demonstrate the potential of magnetophoresis to selectively isolate sickle RBCs, which could advance SCD diagnostics, transfusion processing, and research into HbS-containing cells.