Earlier studies used simplistic models that assume human cells are spherical. But many cells - for example, muscular and red blood cells - are not spherical. Sebastián's team therefore developed a more sophisticated model that accounts for cells that are shaped like rods, cylinders and rugby balls. "If we are to understand the biological effects of electromagnetic radiation, it is essential we consider the combined effects of shape and cell interaction", says Sebastián. The researchers investigated the effects of radiation from 900 to 2450 MHz - the range we are exposed to by mobile phones, microwave ovens, and police and air-traffic radar.

Sebastián and co-workers found that the electric fields in ellipsoidal and cylindrical cells were higher than those observed in the simulations of spherical cells. They also noticed that polarizing effects in cells aligned with the electric field reinforce the field in the cell wall. A further refinement that included the effects of water bound within the cell wall showed that, for all cell shapes, the electric field was higher than simpler models predicted.

The current study was performed at a microscopic level, however, and research into the effects of mobile phones are usually based on whole biological structures. "It would be possible to consider a tissue as an aggregate of cells, but I think that a realistic simulation of the electric field would be almost impossible", Sebastián told PhysicsWeb. "But our research could provide better information on radiation exposure effects and possibly establish lower acceptable levels for radiation from mobile phones".