Assessment of 0.5 T static field exposure effect on yeast and HEK cells using electrorotation

Abstract

This study aims to examine the influence of a 0.5 T static magnetic field (SMF) on yeast and human embryonic kidney (HEK) 293 cell using electrorotation (ROT). Following 48 h exposition to the SMF, no difference was noted between ROT spectra of unexposed and exposed yeast cells, which extend previous reports on the absence of SMF effects on yeast. We also compared the ROT spectrum and the extracted electrical characteristics of HEK cells exposed during 72 h to a 0.5 T uniform static magnetic field with those of unexposed cells. SMF potential effects on HEK proliferation kinetics and cell morphology were also assessed by using the trypan blue exclusion method and scanning electron microscopy, respectively. At last, no significant differences were observed between control and exposed HEK cells concerning electrical properties, growth, and morphology.

Figure 1

Halbach cylinder (Magnetic Solutions) producing a uniform 0.5 T magnetic field. (a) Top and side views of the Halbach cylinder. (b) Distribution of the magnetic flux density (2D FEM simulation performed with Comsol).

Figure 2

ROT spectra obtained for unexposed yeast cell using two different medium conductivities: 9 mS/m (square) and 23 mS/m (circle).

Figure 3

ROT spectra of exposed (square) and unexposed (circle) yeast cells. The medium conductivity was set to 23 mS/m (cumulative data, $n_{cells}$ = 10).

Figure 4

Comparison of cell counts in the exposed (gray) and control (white) samples after 24, 48, and 72 h of incubation. The initial cell number was set to $1.6\times {10}^4$ in all experiments.

Figure 5

ROT spectra of exposed (square) and unexposed HEK cells (circle). The solid line represents the fit to the experimental data compiled from nine experiments.

Figure 6

Analysis of cell membrane morphology (magnification = ×10,000). Comparison of SEM microphotographs after 24, 48, and 72 h of incubation for unexposed (a) and exposed (b) HEK 293 cells.