关键词: 有效极化率　介电泳　微电极组　数值模拟

Abstract: A novel microchip integrating quadrupole electrodes and spiral electrodes is designed for measuring the dielectric parameters of cells by utilizing dielectrophoresis(DEP). The conventional DEP (CDEP), travelling-wave DEP (TWDEP) and the electrorotation (EROT) of the cells can be implemented based on this integrated chip. A generalized model on the basis of phasor method is established for the time-averaged CDEP force, TWDEP force and EROT torque. The expressions of travelling velocity and rotational velocity of cells are derived. Then the numerical simulation is implemented for the model solution including the CDEP factor, TWDEP factor, EROT factor and the motion of cells. And the numerical results are compatible with the experimental data in the literature. The results show that the cell radial travelling velocity depends on both the in-phase and out-of-phase components of the effective polarizability of the cell at the heights approximately above 20 m from the electrode surface while suspending height of the cell depends on only the in-phase component of above the height of 20 m. Additionally, the optimal region for EROT measurement is approximately a square area, with the centre of each side lying halfway between the adjacent electrode tip and electrode chamber centre because the torque variation within this area is under 5% and the DEP force is minimum, which is beneficial for EROT measurement. Consequently, more comprehensive and precise dielectric information of cells can be obtained through the multi-mode DEP on this micro chip.

Key words: Dielectrophoresis, Effective polarizability, Multimicroelectrode, Numerical simulation