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Published on: July 28, 2008
Forces on biological cells due to applied alternating (AC) electric fields. II. Electro-rotation
T L Mahaworasilpa1, H G Coster, E P George
1UNESCO Centre for Membrane Science and Technology, Department of Biophysics, School of Physics, University of New South Wales, Kensington, Australia.
Biochimica Et Biophysica Acta
|May 22, 1996
Summary
Mammalian cell electro-rotation in electric fields reveals that only cells not on electrodes rotate. This study estimates cell membrane capacitance and cytoplasm conductivity for K562 and SP2 cells.
Area of Science:
- Biophysics
- Cellular Electrophysiology
Background:
- Understanding cellular responses to external electric fields is crucial for various biotechnological applications.
- Electro-rotation is a technique used to study cell membrane properties and dielectric behavior.
Purpose of the Study:
- To investigate the electro-rotation of mammalian cells (K562 and SP2) in alternating electric fields.
- To analyze the theoretical basis of cell rotation arising from interactions between adjacent cells in electric fields.
- To determine cellular parameters like cytoplasm conductivity and membrane capacitance.
Main Methods:
- Experimental measurement of angular velocities of K562 and SP2 cells in electric fields (0.5 kHz to 12 MHz).
- Observation of electro-rotation for two cells in contact using parallel cylindrical electrodes.
- Theoretical analysis of torque generated by induced electric dipoles and secondary electric fields.
Main Results:
- Only the cell not in contact with the electrode exhibited rotation.
- Maximal electro-rotation occurred in two distinct frequency domains.
- Cell spin speed was significantly lower than the excitation frequency.
- Rotation direction depended on the angle between the electric field and the cell-center line.
- Estimated K562 cytoplasm conductivity at 0.2 S/m and SP2 at 0.3 S/m.
- Estimated K562 membrane capacitance at 2.7 ± 0.8 mF/m² and SP2 at 9.8 ± 0.6 mF/m².
Conclusions:
- The study elucidates the mechanism of electro-rotation in contacting cells, driven by induced dipole interactions.
- Experimental data allowed for the estimation of key biophysical parameters of K562 and SP2 cells.
- Findings contribute to the understanding of cell behavior in electric fields and provide valuable cellular property data.
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