The Effect of Dextrans on Zeta Potential ∗

Abstract

Summary

The effects of dextran solutions (40,000 and 70,000 mol wt) on the electrophoretic mobility of erythrocytes and a negatively charged colloidal particle—minusil—was calculated. Zeta potential was calculated from the standard Helmholtz-Smoluchowski equation. Results showed a decreased zeta potential of erythrocytes in albumin solutions and a plateau effect of both erythrocytes and minusil at a level of approximately —10 mV. Both dextrans uniformly increased zeta potential from —16 mV to an average of —24 mV in saline solutions. However, in physiologic concentrations of albumin, increasing concentrations of 40,000 mol wt dextran increased the negative zeta potential from —10 mV to —24 mV while 70,000 mol wt dextran decreased the zeta potential from —10 mV to —4 mV and then to zero.

The results imply that evaluations of the effects of dextrans on the zeta potential of erythrocytes must take into consideration interaction with albumin. Clinically, from these data 40,000 mol wt dextran would be expected to maintain erythrocyte stability in solution while 70,000 mol wt dextran would be expected to enhance agglomeration.