Exposed

Powerful infrared beams shed light on radiation damage in living cells

ONE of the strongest infrared light sources ever created is giving scientists in California an unprecedented view of the damage inflicted on living cells by radiation and toxic chemicals. Their findings could spark changes in safety regulations for nuclear power workers and those exposed to hazardous chemicals and drugs.

A team at the Lawrence Berkeley National Laboratory near San Francisco is using a powerful light source originally used for making advanced microchips to blast single living cells with a beam that can be focused on an area smaller than the cell. Each type of cell reflects the infrared beam in a unique way, because particular molecules in the cell absorb characteristic amounts of light. Analysing the frequencies in the spectrum of the reflected signal can provide a wealth of information: for example, the scientists can use this "signature" to determine whether DNA strands have been damaged, or if cells have recently died.

Michael Martin, who presented the work at last week's American Physical Society meeting in Minneapolis, Minnesota, recently looked at the effect of ionising radiation on cells. His group's work has shown that previous radiation studies, which were based on less sensitive methods using dyes, may have overestimated the effect of the low doses of radiation to which nuclear plant workers are typically exposed.

These studies may have overlooked an exposure threshold below which no damage occurs, says Martin. If the team's preliminary results are mirrored in larger studies, they could lead to changes in safety regulations. And the researchers have already determined the specific damage that some chemicals cause.

From New Scientist magazine, 01 April 2000.

© Copyright New Scientist, RBI Limited 2000