Cellphones may boost forces on biological tissue
|12:30 09 April 04|
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Mobile phone radiation may cause a massive increase in the forces that living cells exert on each other, suggests a new study from Sweden.
The research could be important in answering the question of whether the radiation from mobile phones cause cancer or other health problems. Many researchers fear the answer is yes, yet they have been unable to come up with any plausible way that radiation from a phone could affect, let alone harm, biological tissue.
The conventional view is that the only way radio waves could damage a cell would be if they were energetic enough to break chemical bonds or heat the tissue, like microwaves. Yet the radiation given off by handsets is much too weak to produce either of these effects.
Finding an alternative mechanism is the "holy grail" for those who believe the radiation is harmful, says Camelia Gabriel of Kings College London, who is carrying out research into microwaves as part of the Mobile Telecommunications and Health Research programme (MTHR) funded by the UK government.
Ideas have been put forward, she says. "But there are no proven mechanisms."
Now Bo Sernelius, a physicist at Linkoping University in Sweden, has a new lead. He modelled the dielectric properties of cells. Water molecules have poles of positive and negative electric charge that are known to create attractive forces between cells, known as van der Waals forces.
These are normally extremely weak, typically around a billion-billionth of a newton. Using a highly simplified mathematical model of two red blood cells, Sernelius calculated what effect electromagnetic fields created by different frequencies of radiation would have on the forces.
He found that the water molecules inside the cells attempt to align their positive and negative poles with the alternating field produced by the radiation. They all end up pointing in the same direction, and this strengthens the van der Waals forces.
According to Sernelius's figures, in fields of 850 megahertz - around the frequency used by mobile phones - the attractive forces appear to leap to micronewton strength. That is a huge jump of around 11 orders of magnitude, and completely unexpected, says Sernelius.
Sernelius's investigation is only theoretical, and adverse effects from cellphone radiation are unproven. But if the effect could be confirmed experimentally it could form the basis of an explanation for tissue damage: stronger attractive forces between cells might make them clump together, for example, or cause blood vessels to contract.
The finding is important, says Katie Daniel, deputy editor of the journal Physical Chemistry Chemical Physics, which has just published the study (vol 6, p 1363). "It highlights the idea that electromagnetic radiation might act on cells by affecting the attractive forces between them rather than simply causing heat damage to tissue."
Gabriel agrees that the new mechanism is plausible. But she points out that Sernelius's model is extremely simple, and what applies to two cells may not necessarily apply to more. "It needs to be tested experimentally," she says.
Sernelius suggests checking the dielectric properties of different types of biological tissue during exposure to radiation across the range of frequencies normally used by mobile phones, which is exactly what Gabriel and her colleagues are working on for the MHTR. Their results will be published in December.
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