Capillary magnetophoresis of human blood cells and their magnetophoretic trapping in a flow system.

The performance of a capillary magnetophoretic device was improved by enhancing the magnetic field gradient using a pair of small iron tips attached to the Nd-Fe-B magnets. The magnetophoretic intensity, B(dB/dx), was determined as a function of distance along the gap between the tips from the magnetophoretic velocity of a 3 microm polystyrene microparticle in 0.6 M manganese(II) chloride solution. The maximum intensity was increased 4.5 times by the attached iron pieces. The magnetophoresis of a single human blood cell in 0.1 M manganese(II) solution was studied by this method and its magnetic susceptibility was estimated. Magnetophoretic trapping of red blood cells was demonstrated under counter-current flow conditions in the capillary.