The causes of death are unclear, but detailed analyses led by chemistry graduate student and lead author Xinyuan Liu showed the flies were affected physically. In some, the carbon nanoparticles covered them from wings to legs, which may have impeded their movement or weighted them down too much to climb. In others, the nanoparticles clogged their breathing holes, or spiracles, which may have suffocated them. In other adults, the nanoparticles covered the surface of their compound eyes, which may have blinded them.
The nanoparticles "glom onto the flies," Rand noted while watching a video of flies in the test tubes. "They just can't move. It's like a dinosaur falling into a tar pit." (Note to journalists: Video is available on request.)
Rand and Robert Hurt, director of Brown's Institute for Molecular and Nanoscale Innovation and the other corresponding author, said the findings are important, because they show that permutations of the same material carbon can have different effects in the environment.
"It's not the nanoparticle per se (that may be hazardous), but the form the nanoparticle is in," Rand said.
In another experiment led by Daniel Vinson, an undergraduate student in engineering, adult Drosophila coated in multiwalled carbon nanotubes carried the carbon on their bodies from one test tube into another and deposited some of the particles in the clean tube. That test showed how insects could be vectors for transporting nanomaterials, Rand said.
While two generations of fruit fly larvae showed no
|Contact: Richard Lewis|