New path for DNA damage from nano-particles: study

The stunning discovery adds to a growing body of research highlighting proven and potential health hazards from the rapidly expanding universe of engineered objects measured in billionths of a meter.

Nano-scale products already widely in use range from cosmetics to household cleaning products to sporting goods. But the new findings, reported in the British journal Nature Nanotechnology, could also point to new ways in which nano-therapies might zero in on disease-causing tumors, the researchers said.

They could even shed light on how poorly understood pathogens penetrate into human organs.

In laboratory experiments, scientists led by Charles Case of Southmead Hospital in Bristol, Britain, grew a multi-layer “barrier” of human cells to mimic specialized protective tissues found in the body.

One such barrier, for example, separates blood from the brain.

Underneath this layer three-to-four cells thick, they placed human fibroblast cells, which play a key role in the formation of connective and scar tissue.

And on top they put nano-scale particles of cobalt-chromium, an alloy that has long been used in the making of hip- and knee-replacement joints, and more recently in drug-delivery mechanisms used inside arteries.

Earlier studies had shown that direct exposure to large quantities of the alloy could severely damage DNA is some cells, and the researchers wanted to find out how well the lab-grown barrier would protect the fibroblast cells below.

“We never imagined that it wouldn't,” Case told journalists by phone. “But to our great surprise, not only did we see damage on the other side of the barrier, we saw as much damage as if we had not had a barrier at all,” he said.

At first, the researchers speculated that the tiny particles — barely 30 billionth of a meter in diameter — had slipped through microscopic cracks in the cellular blockade.

But there was no sign of the alloy on the other side, and when the experiment was repeated with far larger particles, the result was essentially the same.

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