Combined magnetic fields increased net calcium flux in bone cells

Low energy electromagnetic fields (EMF) exhibit a large number of biological effects. A major issue to be determined is "What is the lowest threshold of detection in which cells can respond to an EMF?" In these studies we demonstrate that a low-amplitude combined magnetic field (CMF) which induces a maximum potential gradient of 10(-5) V/m is capable of increasing net calcium flux in human osteoblast-like cells. The increase in net calcium flux was frequency dependent, with a peak in the 15.3-16.3 Hz range with an apparent bandwidth of approximately 1 Hz. A model that characterizes the thermal noise limit indicates that non-spherical cell shape, resonant type dynamics, and signal averaging may all play a role in the transduction of low-amplitude EMF effects in biological systems.