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Combined effect <strong>of</strong> pulsed electric and magnetic field on CHO cells dye<br />
uptake<br />
L. Towhidi1, S. M. P. Firoozabadi1, H. Mozdarani2<br />
1Dept. <strong>of</strong> Medical Physics, Tarbiat Modares University, Tehran, Iran; 2Dept. <strong>of</strong> Medical Genetics, Tarbiat<br />
Modares University, Tehran, Iran<br />
The effect <strong>of</strong> pulsed electric field on biological cells such as electroporation has been<br />
a subject <strong>of</strong> many studies in the past. Electroporation as used in electrochemotherapy,<br />
increases the permeability <strong>of</strong> the cell plasma membrane due to pore creation in the<br />
membrane and membrane ruffling which in turn results in enhancing cell dye uptake<br />
(Biophysics.J. 60 (1991) 297-306). We suggest that the synergy <strong>of</strong> conventional<br />
electroporation accompanied by other means <strong>of</strong> energy like applied time-varying magnetic<br />
field (which results in induced electric filed) may increase cell dye uptake due to ruffling<br />
enhancement (Experimental Cell Research, 297 (2004) 348–362). The aim <strong>of</strong> our study<br />
was to investigate the effect <strong>of</strong> time-varying magnetic field on transmembrane molecular<br />
transport – dye uptake by CHO cells exposed to combined pulsed electric and magnetic<br />
field. In order to determine the best set <strong>of</strong> parameters like the shape, size and position <strong>of</strong> the<br />
magnetic coil under which the energy coupling can be maximized, simulation analysis was<br />
performed. Results <strong>of</strong> this simulation indicate that maximum energy coupling between<br />
magnetic coil and sample containing cells is obtained with 8 shaped coils. The coil needs<br />
to be positioned in the horizontal plane so that the sample is positioned directly under the<br />
centre <strong>of</strong> coil where the two windings meet. The smaller the radius <strong>of</strong> the windings, the<br />
greater the energy coupling. This energy coupling is higher at closer distances between<br />
the magnetic coil and the sample containing cells. Employing this simulation results,<br />
we measured in an experimental set up, the variations <strong>of</strong> dye being taken up by CHO<br />
cells using Lucifer Yellow (Biochimica et Biophysica Acta 1668 (2005) 126–137). The<br />
influence <strong>of</strong> magnetic field in our experiments is characterized for both situations in which<br />
it applies (in the range <strong>of</strong> minutes), namely before the electric field application as well as<br />
after itapplication, compared with the presence <strong>of</strong> only electric field.<br />
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