Rotation of cells in an alternating electric field theory and experimental proof

Abstract

Protoplasts of Avena sativa rotate in an alternating electric field provided that at least two cells are located close to each other. An optimum frequency range (20 to 30 kHz) exists where rotation of all cells exposed to the field is observed. Below and above this frequency range, rotation of some cells is only occasionally observed. The angular velocity of rotation depends on the square of the electric field strength. At field strengths above the value leading to electrical breakdown of the cell membrane, rotation is no longer observed due to deterioration of the cells. The absolute value of the angular velocity of rotation at a given field strength depends on the arrangement of the cells in the electric field. A maximum value is obtained if the angle between the field direction and the line connecting the two cells is 45 degrees. With increasing distance between the two cells the rotation speed decreases. Furthermore, if two cells of different radii are positioned close to each other the cell with the smaller radius will rotate with a higher speed than the larger one. Rotation of cells in an alternating electric field is described theoretically by interaction between induced dipoles in adjacent cells. The optimum frequency range for rotation is related to the relaxation of the polarization process in the cell. The quadratic dependence of the angular velocity of rotation on the field strength results from the fact that the torque is the product of the external field and the induced dipole moment which is itself proportional to the external field. The theoretical and experimental results may be relevant for cyclosis (rotational streaming of cytoplasm) in living cells.

Two-dimensional impedance imaging of cell migration and epithelial stratification

“…28 To study migration, the cells on the electrodes were removed using a scalpel. Four cuts were made around the cells, and the rectangular cell layer was then gently removed using a pair of tweezers.…”

Disruption of Cancer Cell Replication by Alternating Electric Fields

“…These include microscopic particle alignment (i.e., the pearl chain effect; Ref. 6) and cell rotation (7,8). With pulsed electric fields of 10 3 V/cm and 100-ms pulse length, reversible pore formation appears in the cell membrane, a phenomenon usually called electroporation (9).…”

Cytostatic response of HepG2 to 0.57 MHz electric currents mediated by changes in cell cycle control proteins

“…Despite these indications of potential oncological applications of CRet, the current knowledge about the cellular response to this and other radiofrequency electrothermal therapies is still very poor. In fact, only a few, minor in vitro effects have been described for fields at frequencies ≥0.1 MHz (11)(12)(13). Consequently, it has been generally assumed that such fields have no relevant biological effects.…”