Magnetophoretic separation of red blood cells

IEC 260

Maciej Zborowski1, Graciela R. Ostera2, Lee R. Moore1, Sarah Milliron3, Jeffrey J. Chalmers4, and Alan N. Schechter2. (1) Department of Biomedical Engineering, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, (2) Laboratory of Chemical Biology, National Institutes of Health/NIDDK, Building 10; Room 9N-307, Bethesda, MD 20892-1822, (3) Department of Bioengineering, University of Toledo, Toledo, OH, (4) Department of Chemical Engineering, The Ohio State University, 121 Koffolt Laboratories, 140 West 19th Street, Columbus, OH 443210
The existence of unpaired electrons in the four heme groups of deoxy and methemoglobin gives these species paramagnetic properties as contrasted to the diamagnetic character of oxyhemoglobin. Using Cell Tracking Velocimetry, we were able to measure the migration velocity of deoxygenated and methemoglobin-containing erythrocytes, exposed to a mean magnetic field of 1.40 tesla (T) and a mean gradient of 0.131 T/mm, in a process we call cell magnetophoresis. Our results show a similar magnetophoretic mobility (MM) of 3.86e-6 mm3s/kg for erythrocytes with 100% deoxygenated hemoglobin and 3.66e-6 mm3s/kg for erythrocytes containing 100% methemoglobin. Oxygenated erythrocytes had a MM of -0.2e-6 mm3s/kg to +0.30e-6 mm3s/kg , indicating significant diamagnetic component relative to the suspension medium, in agreement with previous studies on the hemoglobin magnetic susceptibility. Magnetophoresis may open up an approach to separate cells for biochemical analysis based on their intrinsic magnetic properties.