Magnetophoretic label-free cell separation using paramagnetic solution

In this paper, we present a new magnetophoretic cell separation method based on the magnetic susceptibility differences between cells and medium. Since the dimension of cells is only a few dozen micrometers, it is difficult to discriminate cells only by low magnetic force acting on biological cells. To improve the efficiency of this label-free magnetophoretic separation, the magnetic susceptibility of surrounding solution is adjusted by dissolving paramagnetic salt such as gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), in which cells experiences an enhanced magnetic repulsive force. As the concentration of Gd-DTPA increases, the difference in the magnetic force acting on both polystyrene beads and cells increases, resulting in more efficient separation. Based on these results, we have successfully achieved label-free separation of U937 cells from red blood cells with >; 90% purity and 1 × 10⁵ cells/h throughput.