Effects of static magnetic field on cell biomechanical property and membrane ultrastructure

The bioeffects of magnetic fields on organism have become an attractive area of study in recent decades, but the influence of static magnetic fields (SMFs) on biomechanical property, is rarely reported. This work investigated the effect of SMF (magnetic flux density ranging from 0.26 to 0.33 T, with a gradient of 2.09 T/m) on biomechanical property and ultrastructure of the membrane, and their relationship with F-actin distribution and cell adhesion of human breast adenocarcinoma cells (MCF-7) and human cervical carcinoma cells (HeLa). The two kinds of cells showed different responses to SMF exposure. For MCF-7 cells exposed to SMF for 72 h, the Young's modulus calculated from atomic force microscopy (AFM) indentation curve decreased significantly compared to that in the control group. This reduction was also associated with different actin distribution, revealed by phalloidin fluorescence analysis. Moreover, exposed MCF-7 cells had a smaller adhesion capacity to substrate with a rougher surface as observed by AFM scanning, which was also confirmed by quantitative analysis of the scanning pictures. Nevertheless, no significant changes were observed in the HeLa cell. These findings, from a biomechanical point of view, provide new insights for the mechanism of bioeffects of SMF on cell behaviors.