In other words, getting down to the nanoscale made the metallic nickel particles more harmful and potentially cancer-causing. Kane said the reason might be that for the same amount of metal by mass, nanoscale particles expose much more surface area and that makes them much more chemically reactive than microscale particles.
Another important result from the work is data showing a big difference in how nickel nanoparticles and nickel oxide nanoparticles react with cells, Pietruska said. The nickel oxide particles are so lethal that the cells exposed to them died quickly, leaving no opportunity for cancer to develop. Metallic nickel particles, on the other hand, were less likely to kill the cells. That could allow the hypoxia pathway to lead to the cell becoming cancerous.
"What is concerning is the metallic nickel nanoparticles caused sustained activation but they were less cytotoxic," Pietruska said. "Obviously a dead cell can't be transformed."
Although Kane said the findings should raise clear concerns about handling nickel nanoparticles, for instance to prevent airborne exposure to them in manufacturing, they are not all that's needed to cause cancer. Cancer typically depends on a number of unfortunate changes, Kane said. Also, she said, the study looked at the short-term effects of nickel nanoparticle exposure in cells in a lab, rather than over the long term in a whole organism.
Still, in her lab Kane employs significant safeguards to keep researchers safe.
"We handle all these materials under biosafety level 2 containment conditions," she said. "I don't want anyone exposed. We're handling them as though they were an airborne carcinogen."
|Contact: David Orenstein|