Separation of cells expressed specific antigen on the surface based on dielectrophoresis

Rapid conversion of the line formation with the cells based on dielectrophoresis (DEP) was applied to simple and rapid distinction of cells with specific surface antigens from a cell population. The gap area of the interdigitated band array (IDA) electrode was modified with anti-CD33 antibody. Human promyelocytic leukemia cells (HL-60) which express CD33 surface antigen were accumulated on the surface in the gap area between both bands of the IDA electrode by negative DEP (n-DEP). Switching of the applied voltage of the band electrode brought about the removal of accumulated cells to form another pattern due to the formation of the different pattern of the electric field in the device. The modification with the antibody inhibits the removal of the cells with specific surface antigen due to the irreversible capture with immunoreactions during the first pattern formation. Therefore, we should discriminate the cells with specific antigen from the cell remained on the gap area. The time required for the assay was substantially short, 60 s for forcing and 60 s for the separation of unbounded cells. Furthermore, the present method does not require pretreatment such as target labeling or washing of unbound cells.