Effects of magnetic fields and field gradients on living cells

The principle of nuclear magnetic resonance imaging (MRI) is based on the simultaneous application of a static magnetic field, temporally switched magnetic field gradients, and radiofrequency (RF) electromagnetic signals. The development of MRI as a diagnostic tool has resulted in the installation of thousands of powerful magnets throughout the world. They have become the sources of the largest static magnetic fields to which humans are exposed. Because of safety concerns, the study of magnetic field effects on humans was initiated when MRI was first introduced in the 1970s. Since that time, numerous studies of the effects of magnetic fields interacting with living organisms have either shown no effect or contradictory results. The main reason behind the conflicting findings is the very small diamagnetic susceptibility of living organisms, and especially in cases where the magnetic field-generated forces are smaller than gravitationally generated forces, the effects are below the threshold of significance. However, the MRI industry trend of using ever-stronger superconducting magnets increases the likelihood that such effects will become noticeable, and, possibly, harmful. In this article, we discuss a physical mechanism behind magnetic field interactions with tissues, cells, and cytoskeleton.