Nanoparticles can damage DNA from a distance by affecting biological signals, scientists have shown

Nanoparticles can damage DNA from a distance by affecting biological signals, scientists have shown.

Their influence is not stopped by a protective wall of cells, a study revealed.

The findings have both good and bad implications, experts believe. They raise questions about the safety of man-made particles, but also point the way to new avenues for medical treatment.

Nanoparticles are tiny fragments of material at scales of a millionth of a millimetre, or a thousand times smaller than the width of a human hair.

They are already used in cosmetics, sunscreens, electronics, manufacturing, environmental processes and medicine. Future applications could include novel drug delivery systems and treatments that target cancer. But there are safety concerns, since small particles can display unexpected properties not seen in the same materials at larger scales.

The University of Bristol scientists carried out a study in which they showed that even without making contact, metal nanoparticles can damage DNA.

Although the experiment did not accurately mirror conditions in the human body, it illustrated an indirect mechanism by which nanoparticles can exert biological effects. The scientists grew a tumour "wall" about three cells thick and placed cobalt-chromium nanoparticles and human cells on either side of the barrier.

They found that the cells behind the biological wall suffered DNA damage just as if they had been directly in contact with the nanoparticles. Although the particles could not pass through the wall, they caused the barrier cells to generate harmful signalling molecules that inflicted the damage. The findings were published online in the journal Nature Nanotechnology.

Lead author Gevdeep Bhabra said: "Even though this work was done in the laboratory, our results suggest the existence of a mechanism by which biological effects can be signalled through a cellular barrier, thus it gives us insights into how barriers in the body such as the skin, the placenta and the blood-brain barrier, might work."

The research suggested that the indirect as well as direct health effects of nanoparticles should be taken into account when evaluating their safety, said the scientists. But they stressed that the experiment did not model conditions seen in the human body.