MAGNETOPHORESIS .2. QUANTIFICATION OF IRON AND HEMOGLOBIN CONTENT AT THE SINGLE ERYTHROCYTE LEVEL

The iron and hemoglobin content of individual erythrocytes was determi ned using a method based on parallel velocity measurements during magn etophoresis and gravitational sedimentation of individual erythrocytes in suspension. In previous publications we have suggested employing c ell magnetophoresis, a biophysical phenomenon characterized by cell mo vement in a fluid under magnetic field influence, for cytometry. The p aramagnetic ferric iron in methemoglobin is used as a magnetic label. The iron content is estimated from the magnetophoresis velocity, and h emoglobin content from the gravitational sedimentation velocity of ery throcytes. Blood samples are also analyzed in a Coulter counter to det ermine their mean corpuscular hemoglobin. The time course of the react ion of methemoglobin reduction is quantified at the single erythrocyte level. The methemoglobin content in individual erythrocytes is determ ined following the oxidation reaction. Erythrocytes from patients with normo-, hypo-, or hyperchromic anemia exhibit magnetophoresis and gra vitational sedimentation velocities that correlate closely with mean c orpuscular hemoglobin. We propose the utilization of magnetophoretic c ytometry for detailed diagnostic studies at the single erythrocyte lev el. Furthermore, the magnetophoresis velocity to gravitational sedimen tation velocity ratio is proposed as a standard value for comparative study of magnetically labeled cells in future investigations, as it wa s found to be constant and independent of hemoglobin content. (C) 1995 Wiley-Liss, Inc.