Destruction of targeted cancer cells using magnetizable beads and pulsed magnetic forces

We investigated the destruction of targeted cancer cells using two types of magnetizable beads and pulsed magnetic forces. TCC-S leukemic cells were combined with magnetizable beads of diameter 4.5/spl plusmn/0.2 /spl mu/m and 2.8/spl plusmn/0.2 /spl mu/m by an antigen-antibody reaction. The cell/bead/antibody complexes were suspended in 1 ml of medium in a 1.5 ml tube, and a magnet was used to aggregate the beads. The aggregated cell/bead/antibody complexes were then stimulated ten times at 2 s intervals using a circular coil, which produced monophasic pulses of 150 /spl mu/s duration and a maximum magnetic-field strength of 2.4 T at its center. The viability of the cells was then assessed using the trypan blue stain. The viabilities of the stimulated groups were significantly lower than those of the control groups, for both the 4.5 and 2.8 /spl mu/m beads. In addition, the viabilities of the stimulated groups containing 4.5 /spl mu/m beads were lower than those containing 2.8 /spl mu/m beads. Furthermore, the viabilities of the stimulated groups with 4.5 /spl mu/m beads decreased as the number of beads increased. We propose that the instantaneous pulsed magnetic forces caused the aggregated beads to forcefully penetrate or rupture the targeted cells. We therefore conclude that the use of large numbers of magnetizable beads with a large diameter can effectively destroy cells targeted by an antigen-antibody reaction.