An electrorotation technique for measuring the dielectric properties of cells with simultaneous use of negative quadrupolar dielectrophoresis and electrorotation.
This paper presents an effective electrorotation technique for measuring the dielectric properties of cells using a superposed electrical signal, which can simultaneously generate negative quadrupolar dielectrophoretic (nQDEP) force and electrorotational (ROT) torque. The proposed technique involves a three-dimensional (3D) octode, which includes four electrodes arranged in a crisscross pattern on the top and bottom of a microchannel, respectively. A single cell was trapped in the center of the 3D octode by the nQDEP force and simultaneously rotated by the ROT torque. Using the proposed electrorotation technique, ROT spectra of human leukocyte subpopulations (T and B lymphocytes, granulocytes, and monocytes) and metastatic human breast (SkBr3) and lung (A549) cancer cell lines were accurately measured without any disturbance. Torque on the cells generated by the ROT signal was analyzed theoretically based on the single-shell dielectric model for the cells. Furthermore, the dielectric properties of the cells, such as area-specific membrane capacitance and cytoplasm conductivity, were extracted using the measured ROT spectra and the analyzed torque.
Department of Nano Engineering, Center for Nano Manufacturing, Inje University, 607 Obang-dong, Gimhae 621-749, Republic of Korea.
Song-I
SI
Han
Young-Don
YD
Joo
Ki-Ho
KH
Han
D001940:Breast / Q000166:cytology; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry*; D003593:Cytoplasm / Q000737:chemistry*; D025802:Electric Capacitance; D004553:Electric Conductivity; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000737:chemistry; D008168:Lung / Q000166:cytology; D008954:Models, Biological; D012399:Rotation; D019415:Torque