Observation of Red Blood Cell Membrane Charge Using Magnetic Beads Under Pulsed Magnetic Field

Aggregation of red blood cells (RBC) is one of many factors that impair vascular circulation and is closely related to the zeta potential. Pulsed magnetic field (PMF) is effective in improving RBC aggregation and mobility. Therefore, this study aims to observe indirectly the change of RBC membrane charges using negatively charged magnetic beads (MBs) and to elucidate the effect of PMF on RBC aggregation via zeta potential. Since concentrations of hematocrit (Ht) and plasma are different for each person, in order to objectify the zeta potential, RBC suspension was prepared using phosphate buffered saline (PBS) which is a protein-free buffer and prevents RBC agglomerating. Tert-butyl hydroperoxide (tBHP) was also used to oxidize agents to understand RBC aggregation in an environment of tumor cells or inflammation. Our PMF stimulator has a maximum intensity of 0.27 T at a transition time of
$102 \mu \text{s}$
with pulse intervals of 1 Hz. The number of RBCs attached to MB was higher in the PMF group than in the control group. In addition, in the oxidized blood, the number of RBCs attached to MB decreased compared to that of the control group, but it was increased after PMF treatment. In the PMF-treated group, a larger number of MBs attached to RBCs was also observed. Our results could be interpreted that the instantaneous flux change of PMF increases negative charge density on RBC membrane, thereby increasing zeta potential between RBCs, inducing disaggregation of RBCs, thus eventually contributing to the improvement of blood circulation. PMF suggests the possibility of being used as a noninvasive treatment for preventing blood circulation disorder. Further study needs to verify the effect of PMF on the changes in plasma concentration in patients with cardiovascular diseases such as atherosclerosis, thrombosis, and hypertension.