Hiroko Imasato

Separation of Leukemia Cells from Blood by Employing Dielectrophoresis

Our goal is development of a new automatic blood cell counter that it can detect a small amount of leukemia cells in the blood of patients. We employ the dielectrophoresis (DEP). In this paper, we examine whether or not realization that a living blood cells are separated by employing the dielectrophoresis. Leukocyte and erythrocyte are separated by dielectrophoresis under 60MHz, 10Vpp. Furthermore, normal leukocytes and BALL-1 which is one kind of leukemia cells were separated under 37KHz,14Vpp

Development of microwell array for dielectric characterization of circulating tumor cells

Electrorotation is a noninvasive technique to measure the dielectric properties of biological cells. In this paper, We fabricate an electrorotation microwell array for high-throughput dielectric characterization of circulating tumor cells (CTCs). The device consists of a microwell array and electrorotation chip. The practicality of the device was evaluated using PC-9 cells. The PC-9 cells were captured single cells in the microwells and measured electrorotation spectrum, which reflects its dielectric properties.

Design and evaluation of electrode for dielectrophoretic characterization of blood cells

Dielectrophoresis can be used to determine the dielectric properties of biological cells. In this paper, we present an electrode design for characterization of blood cells by measuring negative dielectrophoretic force. The negative dielectrophoretic force acting on glass beads in distilled water was measured by inclined gravity to evaluate the effectiveness of the designed electrode. The designed electrode generated the negative DEP force ranging from 0.21 pN to 1.89 pN with 20 Vpp, 1 MHz. The distribution of the dielectrophoretic force was consistent with the calculated results.

Design of ceiling electrode for cell separation using positive Dielectrophoresis and inclined gravity

Dielctrophoresis (DEP) is a movement of particles in medium by a force, which is generated in non-uniform electric fields. The Dielectrophoretic force (DEP force) depends on the geometry of an electrode. In this paper, the design and the simulation of the ceiling electrode to separate biological cells by using positive dielectrophoresis and inclined gravity are presented. The positive DEP force which is generated around the designed ceiling electrode is measured by inclined gravity.

Dielectrophoresis: Integrated Approaches for Understanding the Cell

The complex permittivity of a biological cell reflects its substance and structure and thus seems to reflect its function, activity, abnormality, life/death, age, and life expectancy. Although it may be very difficult to measure the complex permittivity of each cell, the movement or behavior of the cell as affected by its complex permittivity can be observed under the microscope. The dielectrophoretic force (DEP force) generated on a particle in a nonuniform electric field causes movement of the particle in accordance with its complex permittivity or polarizing characteristics. Thus, differences in the substance or structure of biological cells lead to differences in their movement or behavior in a nonuniform electric field. The principle of dielectrophoresis (DEP) and the estimation of the DEP force are described in this chapter. The distinctive features of DEP are applied in the separation of biological cells, e.g., leukocytes from erythrocytes, leukemia cells from normal leukocytes. This cell separation ability is affected by the frequency and amplitude of the applied voltage. To estimate the DEP force generated on a single cell, the terminal velocity of the cell in the medium should be measured withouttaking it out of the DEP device. The procedure to measure the terminal velocity is also described.