Electric-field-induced volume and membrane ionic permeability changes of red blood cells

When an external electric field (EF) is applied to red blood cells (RBCs), the RBCs are observed to undergo a swelling action. The swelling may or may not lead to hemolysis, depending on the EF strength. An objective verification of this swelling is by measuring the RBC mean corpuscular volume (MCV). In this study, the RBC´s were exposed to the appropriate EF strength to induce swelling, but caused minimal hemolysis. The MCV was measured. The change in the erythrocyte membrane ionic permeability as a result of the EF exposure was also determined, as an objective verification of presumed membrane conductance change concomitant with the swelling. The fluxes of cations K ⁺, Na ⁺, and Ca ⁺⁺ and anion Cl ^- were measured. The results showed that red cell MCV was indeed increased after EF application. The EF also altered the membrane ionic conductance to allow ions to flow down their respective concentration gradient across the membrane. Without a counterbalancing ionic pressure gradient, hemoglobin colloidal pressure inevitably drew H ₂O in, thus producing the observed swelling.